Ce =i,
and
Spe — ES pet é dT-T Xv ou dT+F,4+ RT Sy
ee Miners CMe Nee chy TT Te ant Pg al Seal
C es, = So RT i a =i
(5) reduces to:
de ) 5) F
SS ie Tie ST nN oe eC)
dt TT
In the second place we must prove the validity of this formula
for reactions in dilute solution. For this purpose we introduce a new
quantity, «’,, determined by the relation :
He LG ONT rsd os eee (©)
1
So RV logn, is that part of the thermodynamic potential that
is in connection with Gipps’s paradox, and w, the remaining part.
Now as is known, the differential quotient of w, with respect to
the concentrations ') remains finite, whereas that of the second part
1) In contradiction to what is usual in the treatment of velocities of reaction,
we define the concentrations here as molecular percentages of a certain substance in
a definite mixture, and not as this quantity divided by the total volume. But it is
clear that this does not affect the conclusions about the constancy of hk, and ha,
as in every reaction in a dilute solution the change of volume during this reaction
is disregarded.
becomes infinite for exceedingly dilute solutions. For the (of course
also very slight) changes to which the concentrations in an exceedingly
dilute solution can be subjected we may, therefore, consider w,, Ww,
ete. as invariable, independent of the concentrations, when we take
the variations of RT log n, ete. with the concentration. into account.
If we now substitute the value (5) for u,, and bring down the term
RT log n, trom the exponent, we get again:
le
— - =k, Mn, — k, Mi’, (da)
where :
SE, sn li =, af Lee
rol RT :
—r en k, =e eos Oo (0)
may be considered as constants according to the above, as is required
by the law of the mass-action.
We conclude from this equation (4 and 47) that really equation (2)
can properly account for a highly important property of the course
of the reaction. This result was by no means to be considered as
certain beforehand. For we have drawn up this equation by analogy,
and drawn attention to the close agreement with the use of equation (1)
in this and the preceding communication, but not to the existing
differences. It is here the place to set forth these differences. It is
true that in the ease of the “osmotic temperatures” the final state
is no state of equilibrium, but each of the two homogeneous phases
may yet be considered as in equilibrium, if we leave the immediate
neighbourhood of the membrane out of consideration. So we are
undoubtedly justified in speaking of quantities as temperature, entropy,
thermodynamic potential in each of the phases, and there the formula
was applied only to that final state “of equilibrium of mass exchange”.
But not without justification it might be doubted whether the same
thing is allowed for states in which the equilibrium of mass exchange
has not yet set in, and a fortiori this holds for the case under
consideration. For the homogeneous phase in which the reaction
takes place, is not in equilibrium in itself; it is not certain that
Maxwe’s distribution of velocities holds there, and even if with
BOLTZMANN we want to introduce a definition for the entropy of a
state of non-equilibrium, it will, of course, in general have another
value than the 4 from equation (2).
Now it appears from equation (4) that all the same these undoubt-
edly weighty objections need not lead to a rejection of equation (2).
For the very extensive material of facts concerning the reaction
vt ten
velocities proves conclusively that equation (4) applies to a great
number of reactions that proceed with measurable velocities. Parti-
cularly it has been ascertained by numerous measurements that /°,
and f#, are really constants in reactions that proceed normally '),
so they are not quantities that depend on the time. If the influences
which we mentioned, made themselves so strongly felt that equation
(2) had to be rejected, this result would be impossible. For as the
mixture more and more approaches the state of equilibrium during
the reaction, and at last reaches it, the difference between the entropy
which really exists at any moment (Borrzmann’s /H-function) and the
entropy of the state of equilibrium will continually decrease, and at
last become zero; and this remark applies to all the other mean
values occurring in equation (2). But then also the /, and £, would
necessarily become dependent on the time, and not only the Ze, !
and Hele as experiment teaches. So we must conclude that the
systems with measurable velocities of reaction may be considered as
quasi-stationary systems, for which not only an entropy, a thermo-
dynamic potential etc. exist, but for which these quantities (leaving
the influence of the concentration unconsidered, of course) even differ
immeasurably little from the corresponding quantities in the state of
equilibrium. Now an experimentally firm basis has been given as
a support for us in our further examination and development of
equation (2). More particularly it has now been proved, that #’, and
I’, can really only depend on quantities which are constant during
the reaction as we supposed in § 1. However more ensues from
this supposition than has been proved yet. We come back to this
in § 5.
§ 3. Our second step is now to show that equation (2) differs from
the equation (11) of the preceding paper holding for ‘osmotic
temperatures” in this that here /’, does not comprise the pure tempe-
rature functions of the thermodynamic potential with negative sign,
as it did there. For the equation of the equilibrium requires the
equality of the sums of the thermodynamic potentials of the two
systems, and so for rarefied gases :
1) We mean here by ‘abnormal reactions of course reactions for which further
investigation makes it plausible that the inconstaney of k is to be ascribed to
after reactions, by-reactions, catalysis or loo great concentrations.
( 794 )
See | ATERT Sv Ine tRIZ», =
ey
vd rE, | T |
Il ryy
«
. ney
I]
pi Re IS as Se . fyjipeshy ah Tp | ; te
= =P) For] PEM Pig FEM, fey 24 THOS | AT4+RT Deny |
a
| 7) Sy
i RT Sy . ° . . . . ° (
~l]
—
on the other hand equation (2) requires that:
i oe eA SAM id, o ((')
for the equilibrium, where the velocity = 0.
If #, were the same function as in equation (11) of the preceding
paper, this would lead to:
Srye,, + RTZv, + RE ZY lng = Try ey + RIS HERTZ yy Inq, (9)
and this equation is in conflict with the undoubtedly valid
equation (7) as in general the specific heats of the reaction products
and of the reacting substances are not equal and the constants of
entropy do not occur in the latter equation. This observation is not
new. It is namely at bottom identical with the argumentation on p.
45—51 in Mr. pe Lanaen’s Thesis for the doctorate '), that the
omission of the pure functions of the temperature from the formula
for the thermodynamic potential for chemical reactions brings us in
collision with Van “r Hors equation. For the latter is imme-
diately obtained by differentiation from (7), whereas differentiation
from (9) yields the equation of p. 46 of Mr. pr LanGnn’s Thesis for
the doctorate, which is in opposition to it. Mr. pu Laxepy concludes
from this that the kinetic gas theory and thermodynamics are here in
conflict.
But this conclusion cannot be maintained. For it has been over-
looked that for the kinetic derivation of the thermodynamic potential
of a mixture of chemicaliy interacting substances, we shall have to
take BourzMANN’s*) ‘‘kritiseche Réume” into consideration, and that
when the heat of reaction varies with the temperature, terms must
appear which are dependent on the difference of the specific heats*).
What the relation must be between these terms and the temperature
and the specific heats, could only be revealed by a perfectly developed
kinetic theory, which could at the same time give an account of
the value of the specific heat of the different substances. So at present
thermodynamics leads us further in this respect, though it naturally
') Groningen 1907.
2) Gastheorie IL Absehnitt VI.
3) log. (cit. yo. 90:
Roan
( 795 )
must leave the question undecided why and how the specifie heat
varies with the temperature and with the character of the substances.
§ 4. If we now compare equation (7) and (8), it appears that:
Ey = eee ee eee eer ce cy (tA)
and as according to § 2 neither /, nor /’, can be dependent on
the time during the reaction, equation (8) is satistied throughout
the reaction. The same reasoning holds of course with very little
change for dilute solutions too, and then also leads to equation
(10). So it appears that in § 1 we have defined these functions
not closely enough, when we introduced them as functions of
the temperature and of constants characteristic of the reacting
substances, and eventually of the occurring intermediate states. For
the supposition :
PUI ac tbh yee)
Fi = FF. (L,a,, be; 20)
would be in accordance with this definition, in which «@,, 4,, ¢, are
characteristic of the system before the reaction, a,, 6,, ¢, for the
system after the reaction, and mutually independent. Nay, this
supposition would even be the most obvious one. Equation (10),
however, shows that it must be rejected. The constants in /’, cannot
be independent of those in /’,; they must be quantities which in
some way or other are equally in relation with the two systems,
that before and that after the reaction *).
The simplest supposition then would be that all these constants
were = 0, and so that /’ would be a pure general function of the
temperature, like the ‘/, R7’/i7'*) from equation (11) of the preceding
paper, or that possibly this too would be wanting, and /’ = O
might be put. However, on this supposition we come to just such
an absurdity as made us reject equation (4) in the preceding paper.
For from experimental determinations of:
. wy
I
cle a ie Se Re i ee een
Sve, T Sm, 4 Sv fer, a | = at + RTEp,
a Sara Jaye!
Ce
and . Cory
<< be OE PO ee coe VL RTS
:
1) Perhaps pure dissociations e.g. NO, <= 2NO, will only have to be excepted.
=!
OE, — i me *
( 803 )
Such an influence’) would occur, if the specific entropy of the parts
of the reacting mixture should be changed by the catalytic agent,
but not the specific energy. The mutual entropy of the system
catalytic agent + reacting mixture in the ideal gas state would have
another value in this case, than is given by Gipes’s paradox, while as
usually in the ideal gas state no mutual energy would oceur. To explain
this we should have to accept a change of the chemical volumes (Bo.rz-
MANN’S ‘‘kritische Raume’’) of the reacting mixture by the catalytic agent.
A modified intermediate state would, of course, occur here too;
hence the equilibrium will be reached with another velocity,
3. By the addition of a substance which does not take part in the
reaction also the specific energy of the reacting substances is changed
either because only the mutual attraction in the mixture becomes
different — new «a’s appear in the equation of state — or because
stronger causes are active (association of the solvent with one of the
reacting substances’. Of course also the velocity of reaction will change
in both eases. To this category belong all ‘milieu’ influences, of
course, (e. g. changes of electrolytic dissociation with change of
solvent}. Also the displacements of the equilibrium under inflnence
of light or electric discharges may belong to it, e.g. the light-equili-
brium of sulphur in CS,, which sets in with a certain intensity of
illumination, and whieh returns to its former state when the old
state of illumination is restored. Here too it must be assumed that
in consequence of the illumination the energy of the reacting sub-
stances is modified *).
4. The last mentioned cases, however, can also belong, either all
of them or partly, to another category. For it is possible that they
are no real equilibria, but are in the same relation to them as the
case of the “osmotic temperatures” to that of real equilibrium, or
in other words that the modified state must always be accompanied
by a “eurrent of energy’, an absorption of heat or electric energy
and emission of heat. Then the displacement would not be maintained
1) We wil leave it an open question whether the cases cited as such in the
literature should not really be ranged under 3, but think that we should at least
mention this possibility for completeness’ sake because the considerations of van ‘a
Horr l.c. p. 2l which indeed only seem to be intended for heterogeneous catalysis,
do not prove as far as we can see, that a case of homogeneous catalysis of tits
kind is excluded by the second law of thermodynamics.
2) Cf. Sirs. These Proc. XIf p. 356. Of course the false equilibria, which are
reduced to the absolutely stable state by light or an electric spark do not belong
to this category; they belong under 1. |
( 804 )
if we could enclose the system between absolutely reflecting walls
in the new state, and if we could thus maintain the same state of
radiation, but without absorption of new energy. Such a system
would no longer respond to the laws of thermodynamics, even if
we inelnded among them the thermodynamics of radiation, in the
same way as we found that for the “osmotic temperature” the ther-
modynamic law of constaney of the thermodynamic potential is not
fulfilled. Our experimental and theoretical knowledge is not sufficiently
advanced to decide whether the photo- and electrochemical “equilibria”
belong to this or the preceding category *).
Physics. “Some remarks on the mechanical foundation of thermo-
dynamics.” I. By Dr. L. 5. Ornster. (Communicated by Prof.
H. A. Lorentz).
(Communicated in the meeting of December 24, 1910).
In order to deduce the second law of thermodynamics the theory
of ensembles of systems is often used. This theory has been largely
discussed by J. W. Gises in his well-known Elementary Principles
of Statistical Mechanics. In his book two kinds of ensembles, the
canonical and the microcanonical, come to the fore. The latter kind of
ensembles has been used by Dr. Paur Hrrrz who held some views
which give me oceasion for a few remarks ”)
§ 1. In the beginning of his paper Dr. Hertz explains that it is
rational to use for the study of the phenomena shown in a given
system the ensemble of states taken by that system when left to
itself. Such an ensemble is usually termed a time-ensemble. As
the observed phenomena must be considered as the result of many
phases adopted by the system during the time of observation, we
have every reason to presume, that our observation teaches us
something of the mean value in the time-ensemble. By using the
terminology of poly-dimensional geometry we can put the following
1) We will point out that it is sometimes still impossibie to assign a place
in this classification to a phenomenon in the department of catalysis It is e.g.
difficult to explain in what connection with the mentioned cases the fact is
that the thermodynamic potential of perfectly dry solid NH,Cl is so considerably
modified by the addition of the slightest trace of moisture, as appcars from the totally
modified partial vapour pressure of the NH,Cl molecules. Perhaps this case will
appear to be an example of 2.
*) Ann. der Phys. Bd. 30, p. 236, 1910.
———
ioe
( 805 )
considerations in a geometrical form. The state of a given system
of n degrees of freedom is determined by 2 general coordinates
Q:---Q»---Q and the n corresponding momenta p,...p,... pn. If
we take these 27 variables as the coordinates of a point in a space
Ry, (extension in phase) a point of this space will then represent
the state of a system.
All the points taken by the representing point for a system left
to itself, will le in a (2n—1)-dimensional space /s,—1, of which
the equation is as follows:
E (Oho cs Macy Ch ooChao U/C 6 6 Gon op (il)
The form of the function ¢, which represents the enerey, depends
on the kind of the given system. The motion of the representing
point in the space £5 —, is determined by 2n differential equations
of the form
: Of
Li =, © Og
(» taken from 1—7)
: Os
Qu = Op, ’
and by the 2m initial values of the p’s and the q’s. The point passes
through a line in the space /,~,, which I shall indicate as the
trajectory ZL. Like Einsrety') Dr. Hurrz assumes that the trajectory
L perfectly fills the whole space /,.-;. Making use of this hypo-
thesis they then demonstrate that the mean value of a quantity ina
time-ensemble is identical with that in the microcanonical ensemble.
For this reason, it is possible, to reduce the study of the properties
of an arbitrary system to that of a microcanonical ensemble. This
ensemble consists of a layer between the spaces « and « + de filled
homogeneously with systems of a Qo, density. If in the limit de is
taken equal to O and os, to infinite, but in such a way that 2, de
remains finite, we get an ensemble in the space /,—,; which is
filled with a space density Q2,—;; the thus formed ensemble will be
called an energy-space ensemble. We have to specify the terms mean
value in an ensemble and probability of a state. Before I pass on
to that, I shall examine more closely the hypothesis already mentioned
of Eiystin and Hrrrz.
It is impossible for a system to pass rigidly in a finite time (what-
ever length it may have) through all the possible phases; and in
calculating a time-average such a finite time must be imagined.
1) A. Etnstem, Ann. d. Phys. Bd. 11, p. 170, 1903.
( 806.)
Porncaré and Zermero have elucidated that the trajectories of the
systems are in general closed and there are many cases in which
we find closed trajectories which do certainly not pass through all
the points of the space /y,~-). 1 shall give some examples as an
illustration of this. If the kinetic energy which we have adopted
using the dynamical equations in the canonical form, is a homogeneous
quadratic function of the momenta (the coefficients being functions
of the coordinates), the system in which the momenta have been
reversed, will be represented in the same space /y2, -). A certain path
ZL being given, we can attain another possible path L’ by reversing
the momenta at all points «,6,¢ of the path 4; and the path 7’
can be passed through in such away that the interval of time between
the two moments at which the positions 4’ and a’ are reached is
equal to that between the moments at which first @ and 6 were
attained. I shall term those systems reversed systems, their paths
reversed paths. If is now not necessary that the path and the reversed
path are parts of the same trajectory and if they are not, there exist
at least two totally insulated trajectories in the space /2,—1 and each
of them cannot possibly run through all the points of 42,1. In
order to give a simple example, we might consider the following
case; within a sphere two material points are moving with equal
velocity, which are reflected mutually and through the walls as
perfectly elastic bodies. We can choose of all possible motions that
one in which the two points move along the sides of a square. Now
iwo assumptions are possible :
1. The points move in the same direction; in that case the reversed
path will never be reached.
2. The points move in opposite direction; the path and the reversed
path will be the same.
Placing more points into the sphere we can, even if we ascribe
a finite extension to the points, so that the distribution of velocities
may be changed by the mutual impacts, always find an initial state
such that in one case the path and the reversed are the same and
in the other case not, while all the trajectories lie in the same space
Eee ay
One might ask if in case the path of a system does not exactly
reach each point of the space /2,-1, it could not be possible that in
the course of a sufficiently long time it would pass as near each
point as we want to? In simple systems having a certain regularity
this is impossible; what will be the case with complicated systems
') Compare Kevin Baltimore lectures p. 486.
TT.) ©
( 807 )
with a great number of degrees of freedom, it is very difficult to say
in general. It appears to me that it will be very rare in any case
for a system which is in a ‘“molekular ungeordnet” state to pass to
a “molekular geordnet” one.
Meanwhile a circumstance appears which is favourable for the
hypothesis of Hertz and Eixstew. Though many phases may exist
that cannot be attained by a determined path, these phases can
be indiscernible for observation, for we shall find the same observed
data for systems widely differing in internal state. Taking together
all these “equivalent” states and paths, we get an important extension
of the ensemble which can be used to deduce something about the
observed quantities. And though there is, strictly speaking, no direct
connection between the systems taken into account, our results may
teach us something of the systems of observation.
Another favourable circumstance is that a great part of the systems
of a microcanonical ensemble differ very little. The same is true for
the states which a system successively passes through. The system,
equivalent fo the greater majority of the states consecutively passed
through, may be the same as that which is equivalent to the majority
of the systems of a microcanonical ensemble. (The same is true for
a canonical ensemble).
Prudence is however recommended not to generalise this result.
Take for example the case of a large number of perfectly smooth
and rigid spherical molecules enclosed in a spherical vessel, which
walls are supposed perfectly elastic and smooth with respect to the
molecules. The resulting moment of momenta with respect to the
centre is now constant. If an initial state has been given the coor-
dinates of the representing point are limited by the equations
Gs
9
u uv car re ey we ne! | ot)
|
M is a known function of the coordinates and the momenta. The
path of the system will now be confined, to the 2 (7—1)-dimensional
space (2), points of /5,—; lying outside (2) are never reached. For
the majority of the systems possessing a given energy however the
moment J/ will differ only little from O. If one divides the space
Eo, 1 by spaces 1 =0, M=d... in layers, then the majority of
the systems will be situated in the layer (M=0O...M=d), where
J is a very little quantity. The systems of each layer will be equi-
valent for the greater part. Though the path of the representing
point may not pass through all the points, we shall find results of
( 808 )
very fair approximation if we take into account the whole space
Eon—1. )
§ 2. Before applying the theory of the ensembles to the conside-
ration of real systems, I shall point out somewhat more accurately
the idea of mean value and probability. Let us suppose g to be
some quantity relating to a given system, the value will be a function
of the time. The mean value of g in a time-ensemble between the
time ¢, and ¢, shall be given by the formula:
= ] :
A J Wis »s 4 eee (5)
t ta —ty
If we determine the value of a quantity g (for example a pressure,
temperature, or density) it is not the value for a given moment
that comes to expression in our measurements, but a quantity depend-
ing on the values taken by it in the course of the time. It is obvious
to suppose that the mean value as it has been given by (8), is the
quantity found by our observations *).
Making use of this hypothesis we may ask for which of the
time-ensembles imaginable in the space /%,-,; we have to apply
1) The fact that in the case mentioned above the quantity M for the greater part
of the system: of a microcanonical ensemble is 0, shows that we cannot use these
ensembles for those cases in which the moment deviates from O. We can use
for those cases an ensemble formed in the space (2), but it will be more con-
venient to use an extension of the canonical ensembles which has been indicated
by Cipps (p. 38). In this kind of ensembles the number of systems lying in an
element dp, ..dqn of Re, can be represented by
pe = M
Ne © Mo dp, Ber dqns
the quantities ©, My and A are constants. Without going into details for the
moment, I will only remark that in the part of the space in the neighbourhood
of (c=+9, M=M,) the density surpasses that for all the other parts greatly
*) To prove in general that it is this quantity which determines the observed
value of @ will be difficult, for the pressure the proof has bee: given.
In the case of a quantity changing with the time we can still use (3) to define the
value for an interval of time that is sufficiently small to allow us to neglect the change
of the ohserved quantity. The formula (3) however may be used only if v] does
t
not depend on the length of the interval fg—f. It must be possible for the
divergences between ¢ in g| to compensate each other. In the case that ¢] changes
t t
with the time the interval for which ©] can be treated as a constant must be
t
sufficiently long to allow the compensation of the negative and positive values
of o|— 9.
t
( 809 )
the formula (8) and for which interval in the chosen time-ensemble.
Of course this question cannot be answered. We can only remark
that as well for the majority of all intervals in the same time-
ensemble as for the majority of all time-ensembles (3) has the same
value. This value is that of ¢ for a stationary system.
Instead of paying attention to the phases taken successively by a
single system and to unite these to a time-ensemble we can imagine
the path Z filled with some distribution of systems. This kind of
ensembles I shall call line-ensembles. The number of systems on an
element ds of the path is represented by o, ds. The line-ensemble is
stationary if the number of points on the line does not change by
the motion of the representing points. It is easy to indicate the
condition necessary for g, in a stationary line-ensemble.
Let P and P' be two points of the trajectory £ and v and v’' the
velocity of the representing point while g, and 9’, represent the
density in their immediate vicinity. The number of systems lying
on the part PP’ of LZ does not change by the motion of the sys-
tems if
Ow hg id OG. we ah nee nay tomes )
The mean value of ral quantity (f having ral definite value for each
| c J
system, can be defined by
Sy
Jor ds
eige REPO ckc. Henan) chcd ees ioe)
| Q ds
wv
‘}
In this formula s, and s, denote the distance from P and Posto
a fixed points P, measured along the line 4. For the stationary line-
ensemble we find
|| eae di vavigeyschgieraspactes. eis toon meme (0!)
( 810 )
The value of g| is equal to that of P| for the corresponding
.
t
“
ds
interval, as is easily seen if one thinks that represents the time
a
taken by the system to pass through dy. The stationary line-ensemble
can therefore be used to determine the value of observed quantities.
I shall now consider another kind ef ensembles. We divide the
space /2,,—) in elements in the following manner. Let P be a point
of this space and ZL the trajectory through this point. Put in Whe
a space Rs, , perpendicular to / and in the section of #.,—; and
Rs, ) a (2n—L-dimensional element of volume do, containing P.
Through the limits of do the lines “4 ave drawn and in a point
P’ on LF at a distance ds from P a space F's, perpendicular to
Lis constructed. This cuts the paths drawn from do; in the space
(1,1, P's,-1) an element of volume is formed, which is equal to
do (differing only from it in the order of ds).
The volume of the part of the space /,,—1 limited by the elements
do and the lines L amounts to ds do.
We take the element do so small that » may be thought equal for
all points of it and fill the element with a density with repres-
enting points. The number of systems in do ds amounts to
A
do ds — ,
;
or if we put do ds = de
A
dw
y
The mean value in such an ensemble shall be defined by
mG
} f ai)
anes B®
Pie ~ dw
a, v
the integration has to be extended over the whole space /,,_ 1.
(‘)
The definition has been chosen thus because the contribution for a
strip of the breadth do between P? and /” (s, and s,) then amounts to
dole ds
Spe v
% ds
do
fu v
Ss)
ee ie [————e ~~
( 811 )
which for the limit do =O is equal to 7a ‘. I would be possible
t
to take the constant A different for the several strips in which
E,,-, ean be divided; the ensemble attained in this way is also
stationary ?). I shall prove that the ensemble with A constant (the
energy-space ensemble) is the limit of a microcanonical ensemble.
In order to prove this, it is necessary to consider more closely the
velocity v. If we take a point p,....q, it is easy to indicate the
components of v; these are:
. Oke
ae Og»
‘ vp from 1—
Of
ba Np:
eee EN yo (BEM
n ee ie - Ga) 5 6 ed cea Se “CS
This velocity can be connected with a purely geometrical quantity
therefore
relating to the space /,°, in the point p,, q-
The direction-coefficients of the normal on this space in the point
in question («, ,—,) are:
0g
Od,
oo : =
YG He I
I | 0g. 0g \
O&
2 Op,
py =
S| ( ) é ie
I | OF. Op mal
Let 4 denote a distance on the normal, ending on the space
Ho; , €+ de, we shall have
ae de 0€& |
j2— ee Os = fap ess (Ai
\ | 0g. Op, \
. . Je . . . .
If A approaches O we find yi be the differential-coefficient of
Jd.
y
é in the direction of the normal at the space /,—;. Or therefore,
1) I shall prove that do is absolutely constant for a strip.
*) An ensemble of this kind is produceed by cutting through the space Hen—1a
ayer from the ensemble of page 803.
( Bil
dg
SN uae ())
Let us now consider a layer between the spaces I, -; for e and
yo, -, for «+ de as the values of the energy, and let us divide
this layer on the following way in elements. If P is a point in the
space fe, and L the path of the system through the point,
F2,-, perpendicular to “4, we shall take in the section of /2,—1
and /s,—) an element do and draw the trajectories through the
limits of it, let now further P’ be a point on the path and R's,—4
a space perpendicular to 4, in this space an element do’ is formed
by the trajectories. Now at the points of do and do’ we construct
the normals on /,—,, these lines cut /%5,—,, and in this manner
there are formed (27—1)-dimensional space elements of the volumes
Ado and A’do’; the distance of the space ,—; and H’s,—, at the
points P and P” respectively is designate by 4 and 4’. In the time
dt all the systems cross the elements which are situated in the volumes
vdoAdt and v’do’4’dt. But Liouvinies’ theorem teaches us that these
volumes are equal, therefore:
do A = do! {EN Bi.
Taking into account the relation (9) we find:
do de = do' ds
dodo.
We must now suppose that the space between /,~, and 1’s,—1 is
filled everywhere with a homogeneous density o»,; in ‘his way
the microcanonical ensemble of Gipps is constituted. In an element
of the layer doMds lie @,do4ds systems, ds is an element of length
of the path ZL. The last expression can be transfurmed into
do ds
O2n WE
v
If we let now de approach to O and o.,d¢ = A remains a finite
constant, we find in the limit a distribution in the space /y,—, with
the density @2,—1
A
Q2n—1 — — -
Therefore the energy space-ensemble is the limit of the micro-
canonical ensemble.
By the probability of a system I understand the number of systems
in an element of volume that surrounds the point representing the
system under discussion, divided by the total number of systems
in the ensemble.
We shall represent this probability by w, suppose w, and ww, to
£9 ~
( 813 )
be the probabilities of two different states, then we have for the
line-ensemble
wy Vo l 3
We v1
for the energy space-ensemble
Ww, (Be
= = Serr MGs Ree ee @lys
We vy
for the microcanonical and the time-ensemble
i, ib, Ree Oe) Grae ed Bs 9 Us (12).
We can represent the probability of a given system by
C.
‘o°—=. —
.
for the lme-ensemble,
ii — ae
.
for the energy space-ensemble and
iC,
for the microcanonical ensemble *).
1) In order to determine the constants Cy and Cs we can proceed in the following
way. The number of systems in an element dw of the energy space-ensemble and
NC,
in an element @p,...dqa of the microcanonical ensemble amounts to ——— dw
y
and N! C; dp,..@qn, if N and N! represent the total number of systems in the
ensemble. It is easily shown now that we have
wes “dw *dw
a =| v A 0g
iy L 0 N
where the integration has to be extended over the space H2,—1. And further
C; = fap, 5 8 CL —
» "dw
= [doh =a | ==
D
EB
ay
the integral has to be extended over the layer between Hen—1 and E'2;—1,
.
and the integral | again over the space Myn—1.
a
4
In determining the constant C; we have to distinguish between two cases. In
the first place if the path ZL is closed we find
( 814 )
If it is natural to use the line-ensemble for the definition of the
probability of a real system, we see by the preceding discussion
that the energy space-ensembles are also natural for this purpose.
It may be noticed that in all those ensembles the majority of the
systems are equivalent, for observation. If we take the probability
equal for all those equivalent systems, we find a large group which
have a greater probability than all the other systems of the ensemble
§ 3. Let us consider the velocity in some special cases. We have
found for the velocity
n . .
De == Spy st gua):
Suppose that the kinetic energy gets the form
m <= sane 2
Ey == a qu + . . . . . . . . (13)
- |
then we have
2 DOE NG
i iS
vo oe 4+ > dee een
m 1 \Oqr
a
Let us begin with the case that > material points are enclosed
within a given volume. We assume that the points do not exercise
any mutual action, that, however, the walls of the vessel repulse
them with forces which become infinite when a point has penetrated
a very short distance @ into the wall. Within the vessel up to the
walls the forces are neglectable. The points will move into the
walls until their kinetic energy has been exhausted; they then
possess a finite potential energy. During a collision with the walls
de \?
( = is very great in comparison to the potential energy.
Oqy
: “ds
Jueai=c,| = CT
7
OR — ae
the integral taken thus over the path of the system, 7’ is the time which the
representing point requires to get round the trajectory.
In the second place the path can be open, the time T becomes then infinite ;
we have to restrict ourselves to the formula (10). If, however, the path returns
to the initial phase in a time 7” without exactly reaching il, it is possible that
or
always aller the period 7” the same phases ave approximately reached. In this
case w the probability of the phase might be defined by the equaiion :
—_
leek et
(Silos)
We put the expression for v in the form ;
by)
2e
It is easily seen that v is constant (=| ) as long as no
mL -
point is in collision with the walls. During the times that there
are one or more collisions with the walls, » is much larger than
2e
[Y= as the third (positive) term surpasses the second (negative).
We suppose the time of collision to be very short. The path of the
representing point f vc during the collision remains finite (also if 6
e
approaches 0). The path of the representing point is such that if
there are no collisions the p, are constant, while the q, are changing
linearly with the time, while during a collision the representing
point “springs” in a very short time to a new position, where all
the gy, remain the same and also the p, except those which correspond
to the material point, which has suffered the collision. In both cases
the trajectory can never cut itself, if it returns in the same point,
it must be closed.
We can distinguish two extreme cases: Ls‘. the collision lasts very
short in conparison to the average time between two successive
collisions and 2"¢. the reverse is the case.
In the first case the velocity will, during intervals which are
of the same order of magnitude as those between the collisions,
2¢
have the value [xe and it will largely deviate from this value
during very short intervals. If we represent v as a function of the
time by a graph, this will consist of pieces parallel to the axis of ¢
(during the intervals mentioned) interchanged by very steep tops of
whieh the maximum ordinate depends on the maximum value of
Ole Ve . : Ff
ae During an interval of time, very long with respect to the
average time between two successive collisions, the graph will show
very many tops of various heights. In a sufficiently long interval
the tops of each kind are likely to occur in each part of the path.
2
. . . aé
The time during which the velocity [7 - shall be the same
VL
fraction for every path that is sufficiently long, with deviations
which are small in comparison with the quantities themselves. For
53
Proceedings Royal Acad. Amsterdam. Vol. XIIL
( 816 )
example the namber of tops of a certain kind be Vy, for unity
of time then we shall find deviations of the order of magnitude
of yNy, if we compare those numbers for different intervals equal
to the unity of time. If now the duration of the collisions and also
(e.g. by enlarging m) the average time between successive collisions
approaches O, but in such an way that the first is infinitely small
compared with the second, then the (v-/) graph will show an infi-
nity of maxima and minima in a finite region.
In the second extreme case a large number of points differing
widely in phase, will always be in collision with the walls. If the
number of collisions of the given phase is .V pro unity of time then
deviations of the order YN (positive as well as negative) will occur.
The length of the path through which the system passes on the line
Lin a unity of time will be the same for the majority of such-
like intervals. The square root of the mean square of the deviations
is small in comparison with the length of the path itself.
Let us next consider a system in which 7 perfectly rigid and
elastic spheres of diameter o are enclosed in a volume J’. We fix
our attention on a line-ensemble. The points of the line represent
the phases of the system. In some of them the number of particles
for each of the & equal elements J”, into which the volume V’ may
iW
be divided will be exactly —- =v; in others there can exist devia-
tions which I shall indicate by +, for the element V,. The numbers
k
t, answer to the condition S1t,=O. | shall assume the elements
1
”, great in comparison with the mean length of free path (of the
molecules). Then a distribution with certain values of the numbers
t, will last for some time. We can therefore take rather long parts
of the path £ so that on each of them the value of 7, may be
considered to remain constant. Let / be apart in which no deviations
oceur, /’ another with the deviations 7,.
We have to determine
n de 2
>
1 \ 0g,
The sum will show irregular deviations from one moment to
on those parts of ZL.
another, caused by the accidental variations of the number of ¢ol-
lisions.. The mean value however can easily be denoted, it is different
for / and /’. The contribution to the value will depend for each
element on the number of collisions occurring in the unity of time.
ae
( 8i% )
Applying the known elementary theory of mean free path we have
to put this number proportional to (» + 7,)*. If we admit that all
possible configurations still occur in a large number, we can put
for the contribution of the z element to the velocity
(<4 (» + Ten
The coefficient « depends on the nature of the forces in the colli-
ne OE Non ; ;
sions. We therefore find for = (; ) in the system in question :
1 \Oqs,
and for the velocity
Q¢ I:
ca >a) ' 2
B= +eZ(v+t,)
m, 1
For the system with equal but opposite deviations we find:
») i
2¢, ue a
a= + c= (vp —t,)°.
mm ]
k
Taking into account that 2 r,— 0, we find
1
9 I: k
Ep >| ° 1 = 2 =a °
poe ey eee a — vu, te 7,
m 1 ] l
v, being the mean velocity for the homogeneous system.
The mean value of velocity for the deviating system is therefore
always greater than the one for the homogeneous system. The colli-
sions with the walls are neglected, this is permitted, as their number
is much smaller than that of the mutual collisions; moreover their
contribution is for long periods of time the same for the three
systems. The path through which the homogeneous system passes on
k
in a long time 7’is v, 7’, for the deviating systems (»,+ a a) 7, the
; al l
deviations of these values being small compared with the values
themselves. So the path is smallest for the most frequently oceurring
system and equal for deviating but equally probable systems.
53%
( 818 )
Chemistry. — “/nvestiyations on the radium content of rocks.” I.
By Dr. EK. H. Biicryer. (Communicated by Prof. A. F. HoLiemay).
As a second contribution to the knowledge of the radium content
of the earth’s erust,*) I now wish to communicate the results of the
measurements of a few sedimentary rocks. I may refer to my
previous paper for particulars about the method of investigation ;
only the way, in which the substance was brought into solution,
may be briefly exposed. It was much shorter than in the case of
igneous rocks, because the investigation has been limited to rocks
which dissolve for the greater part in dilute hydrocblorie acid. |
took, as usual, twenty-five grammes of the finely powdered rock
and dissolved, gently heating, in 250 c.e. dilute hydrochlori¢ acid. A
usually small residue was left, which, after having been separated
from the solution, was fused with a little sodiumcarbonate. Leaching
with water gave a solution, in which in all cases sulfuric acid could
be detected. The presence of radium being hereby excluded, I rejected
this liquid, and dissolved the very small residue of carbonates in a
few drops of hydrochloric acid. This solution was mixed with the
main solution, which then was measured in exactly the same manner
as described in my previous paper. During the course of the measu-
rements 1 have for the sake of security regauged the electroscope, using
the radiumbromide solution of Professor Rutruirrorp; I obtained
exactly the same value as formerly.
The investigation concerns four samples of marble, six of limestone,
chosen from different geological periods and one of chalk; fresh
specimens of the rocks were supplied to me by Dr. F. Krantz of Bonn.
The results are given in the following table, in which the figures
relate to the quantity of radium per gramme of rock, expressed in
10-2 grammes
Whmny GS See 5 = 9 (Cisne, se oy ok, Seales
oe = =. wl 5S) Piascon Vallevdel Po Saeeetag
a - 2 = = oo Aterbach; Bersstrasses )s.sselan
Ss 2) 6s eae eellmansNassaniges 7 alee es
Limestone, silurian . . Kuchelbad, Prag. . . . 0,7
3 carboniferous. Ratingen, Diisseldorf . . 4,3
e HCA eat Ae oo ai ee os bg os (Ot
lias... . Vaihingen, Wiirttembere 254
= lower chalk . Egestorf, Hannover. . . 0,3
z G0CENEh. » (2 ee eG arIS ery eee cen (OS
Chalk diluvial . . . . Pietersberg, Maastricht. . 4,5
1) These Proceedings XIII, 359 (1910).
(819 )
It is seen, that, if we disregard the sample from the carboniferous
formation, the numbers do not differ much, at least less than was found
for igneous rocks. We do not observe either any relation between
radium content and geological age: the figures in the table are distri-
buted arbitrarily. The same holds for the four specimens of marbles ;
the two first are geologically more recent than the last, but a cor-
responding difference in the quantity of radium present is not to be
found. The general mean of the above numbers is 1,4 and agrees
fairly well with the mean, which can be calculated from different (in
all ten) values, given for limestone by Srrvurr *), Eve *), CoLermer
Farr and Frorance’), Scacunpt and Moors‘) and which amounts to 1,5.
On the contrary a much higher mean of 3,5 would follow from
Joty’s*®) data, whieh relate to twelve rocks of this kind. We cannot
yet settle the question, whether this difference must be ascribed to
chance or is eaused by the small deviations between the methods
of determination. In this connexion, though, I must draw attention
to the fact that Jony, measuring a limestone from Vaihingen obtained
the value 3,0, while in my table the number 2,1 is found; this would
tend to make influence of the method of working more probable.
In conclusion I would like to make a remark on the offen
expressed opinion that sedimentary rocks contain generally less
radium than igneous ones do. As a matter of fact, the mean of all
sedimentary rocks measured is less than that of the igneous, but,
if we divide the last into groups, it becomes evident, that this
difference is only caused by the high radinm content of the granites,
whilst the fact, that an especially great number of samples of this
rock have been measured, tends to make the general mean higher.
If we calculate e.g. the mean of the ten results, obtained by Farr
and Froraxce and by Frutcuer’) for trachyte, we obtaim 1,0, a lower
value than that given above for limestone. Such a result will probably
be also obtained for other igneous rocks; I hope to return to this
subject later on, after having measured further samples of these rocks.
Inorg. Chem. Laboratory University of Amsterdam.
1) Proc. Roy. Soc. A 78, 150 (1906).
2) Phil. Mag. [6] 14, 231 (1907).
3) Phil. Mag. [6] 18, 812 (1909).
*) U. S. Geological Survey, Bulletin 395 (1909).
5) Radioactivity and geology, London 1909, p. 60.
6) Phil. Mag. {6] 20, 36 (1910).
( 820 )
Chemistry. — “On the action of nitrous acid on dinitrodialkyl-
anilines”. By Prof. P. van Rompurett.
According to Hantzscn (B. 48, 1674 [1910}) there is formed by
the action of nitric acid (D. 1.3) on dimethylaniline, 3.4 dinitrodimethy]-
aniline which is regarded by him as a new compound. Apart from
the fact that I obtained this substance many years ago (Ree. VI, 2538
(1887]|) and explained its structure in 1895"), the communication of
HantzscH attracted my attention because in my investigations as to
the action of nitrie acid of widely different concentrations on dime-
thylaniline, I always obtained — dependent on circumstances —
besides tetranitrotetramethylbenzidine *), derivatives of mono- and
dimethylaniline in which the nitro groups occupied in regard to the
amino group, the ortho or para-position, but never the meta-position.
Derivatives with a nitro group in the mefa-position could only be
obtamed by nitrating dimethylaniline in the presence of a large
excess of strong sulphuric acid.
I therefore, have had the action of nitrie acid (D 1.8) on dime-
thylaniline repeated by one of my students, Mr. Jansen. As one
of the reaction produets there is formed indeed a yellow substance
(m.p. 175°—176°) which, however, is nothing else but the well
known 2.4 dinitromonomethylaniline, as was shown from the analytical
results, and also by a comparison with a preparation obtained by
oxidation of 2.4 dinitrodimethylaniline, and with one obtained
from methylamine and bromodinitrobenzene with whieh it did not
cause a depression of the melting point.
On the other hand when it is mixed with the 3.4 dinitrodimethyl-
aniline (m.p. 176°) previously obtained by me, it causes a strong
decrease of the melting point.
As in the reaction described nitrous acid is generated, it is obvious
to assume that by its action on the dimethylamino-group one methyl-
group is split off, a reaction of which, moreover, many instances are
known.
If to the nitric acid (D.1.3) a little urea is first added to remove
any nitrous acid generated, the monomethyl derivative is not
formed, but as main product 2.4 dinitrodimethylaniline (m.p. 87°) is
obtained.
In an experiment where a solution of dimethylaniline in ten times
its volume of nitric acid (D. 1.3) had stood over night, there was
1) Meeting Febr. 23, 1895.
*) Rec. 5, 244 [1886],
re
w
(8941)
obtained, besides the monomethyl derivative, a quantity of 2.4
dinitrophenylmethyInitrosamine.
That, in conjunction with the results of the nitration experi-
ment in the presence of urea, we may explain the reaction in this
way, viz. tha‘ first of all the nitrated dimethyl compound is generated,
and that this is then converted by the nitrous acid (which is formed
by the oxidising action of the nitric acid) into’ the monomethy |
compound (or the nitroso derivative, respectively) is very probable,
but by no means certain. Experiments are still in progress to establish
this. In the meantime, I have studied the action of nitrous acid on
some of the dialkyi derivatives of dinitroanilines.
If we dissolve 2.4 dinitrodimethylaniline in 5 times its weight of
nitric acid (D.1.3) and then add to that solution sodium nitrite until
it acquires a strong odour of nitrous acid, a pale yellow compound
erystallises, which melts at 86°") and is identical with the 2.4 dinitro-
phenylmethylnitrosamine prepared according to Sroprmer*). On
boiling with acetic acid, the nitrogroup is replaced, by hydrogen and
we obtain the 2.4 dinitromonomethylaniline (m.p. 176°). With 2 4-
dinitrodiethylaniline the reaction proceeds in quite an analogous
manner. 2.4 dinitrophenylethylnitrosamine*) (m.p. 52) is formed
which also readily loses NO by boiling with acetic acid, and yields
2.4 dinitroethylaniline (m.p. 114°).
2.4 dinitrodipropylaniline*) is also converted by nitrous acid into
a nitroso compound from which, by means of boiling acetic acid,
the dinitromonopropylaniline (m.p. 97°) may be again obtained.
In the dialkyl derivatives of 3.4-dinitroaniline an alkyl group is also
eliminated by nitrous acid. If, however, we carry out the reaction
in a nitrie acid solution (D. 1.3) it is accompanied by a further
nitration because, as it seems, the nitrous acid accelerates the nitrating
action of the dilute nitric acid.
If, however, we work in a sulphuric acid solution’ vol. of acid,
1 vol. of water) a nitrosomonoalkyl compound is formed even with
these derivatives.
With 3.4-dinitrodiethylaniline, for instance, a beautiful pale yellow
nitroso derivative (m. p. 79°—80°) is formed from which the nitroso
1) [t is sometimes contaminated with the non-nitrosated monomethyl compound.
It will be ascertained whether this is formed primarily, or by the action of the
nitric acid on the nitroso compound. (compare STOERMER loc. cit.
2) B. 31, 2530 [1893].
®) SroreRMER loc. cit. pag. 2531.
4) This compound which | described fully 20 years ago (Rec. 8, 252 [1889]),
described in Hanrzscu’s paper loc. cit. p. 1675 as a new one.
rr
n
eroup is split. off by boiling with phenol or acetic acid. The 3.4-
dimethyl derivative also reacts readily with nitrous acid in sulphuric
acid solution; the compound formed is sill under investigation.
Finally, I have allowed nitrous acid to act on the dark red 3.6-
dinitrodiethylaniline (m. p: 76°) when a beautiful pale yellow nitroso
compound (m.p. 69°) is formed, which on being boiled for a moment
with acetic acid, yields on dilution with water beautiful red needles of
the 3.6-dinitromonoethylaniline (m.p. 120°) previously deseribed by
me, so that in this case also one of the ethyl groups has been eli-
minated. The 8.6-dinitrodimethyl compound behaves in quite an
analogous manner, just like p. nitrodiethylaniline.
These experiments ave being continued with other tertiary nitrated
amines.
Utrecht. University Org. Chem. Lah.
Chemistry. — “Conjirmations of the new theory of the phenomenon
of allotropy.” 1. By Prof. A. Smits and Dr. H. L. pm Lercw.
(Communicated by Prof. van per Waats).
(Communicated in the meeting of December 24, 1910).
As was set forth before’) the above-mentioned theory leads us to
expect that for every substance which presents the phenomenon of
heterogeneous allotropy, so monotropy or enantiotropy, the phenomenon
of homogeneous allotropy will also occur, because the two phenomena
are in the closest connection.
So in virtue of this theory we can expect for the monotropic and
enantiotropic substances that every vapour, liquid, or solid phase in
stable condition consists of an internal equilibrium between different
kinds of molecules. A consequence of this is then that when we
make the temperature vary so rapidly that the internal equilibrium
cannot keep pace with the temperature, the more complex nature
of the substance will appear, which will, among others, manifest
itself in a boiling or melting range of temperature, in which the
final boiling point, resp. final melting point will lie higher or lower
than the unary stable boiling point, resp. melting point, dependent
on the type of the pseudo-system and of the direction of the line
which indicates the internal equilibrium in the vapour, resp. liquid
phase.
') These Proc. March 1910 p. 763.
*
.
a, | ==
( $25 )
As was shown in the preceding communication’) on this subject,
this has reaily already been observed in the melting-point determi-
nation of the rhombic sulphur.
The first substance that was closely examined by us in this
direction was the white phosphoris.
Theory has already drawn attention to the fact that not only the
violet, bunt also the white phosphorus is built up of different kinds
of molecules, so that the possibility existed, that the complexity of
this metastable modification could be demonstrated.
Experiment has corroborated this supposition, and that so convin-
cingly that as yet no substance is known, by means of which
the validity of the theory can be demonstrated in so simple and
clear a way as by means of the white phosphorus.
Before this result was obtained, however, a great difficulty had
to be surmounted, which consisted in the preparation of pure phosphorus.
It appeared, namely, that none of the known methods yielded a
product that melted in a unary way also when the supply of heat
took place very slowly, i.e. a substance was always obtained which
presented a range of melting temperatures.
The melting-heat of white phosphorus being so small (5 eal.), an
exceedingly slight quantity of a second substance can already cause
an appreciable range of melting temperatures, and it was therefore
to be foreseen that the preparation of a product melting at one and
the same temperature might present peculiar difficulties.
As it appeared that the last contaminations must chiefly consist
-in the oxides of phosphorus, which cannot be sufficiently separated
from the phosphorus by the usual methods of purification (treatment
with potassivm dichromate and sulphuric acid, distillation with steam,
ete.) an apparatus was constructed (fig. 1), in which the phosphorus
was distilled in vacuo, and then subjected to a repeated partial
crystallisation, after which it was transferred, thus purified, to a
melting point determination vessel.
The latter is represented in fig. 1 by A. A resistance thermometer
is sealed to it; this vessel is connected with three bulbs B, C, and
D, the Jast of which (capacity 500 cm.) at first filled with water,
was afterwards filled for three quarters with pieces of commercial
so-called pure white phosphorus.
After this phosphorus had been melted under water, and had
then solidified again, the water was poured off, leaving only a thin
layer, and then the tube d was sealed.
YW lve.
( 824 )
Then the tube ¢ was connected with the Gaede-pump through two
U-shaped tubes placed one behind the other.
The first of these tubes was placed in a vessel with solid carbonic
acid and alcohol to condense all the water-vapour, the second being
immerged in a vessel with liquid air to solidify the last traces of
phosphorus so that a high vacuum could be obtained.
Now first of all the apparatus was exhausted, and the flask D
was carefully heated with the flame to distill off the water.
When nothing of the water was to be detected any more we
continued the boiling in vacuo for another half hour to be sure
that also the water dissolved in the phosphorus was entirely removed.
After the connection of the apparatus with the pump had been
broken by sealing it at 6, three fourths of the phosphorus was dis-
tilled over into #4, in which a liquid was obtained, which at first
opalized somewhat, but became perfectly clear and colourless afterwards.
Though this phosphorus appeared to be as pure or purer than the
purest product obtained by other methods, it was not yet pure
enough for our purpose, as experiment showed that this phosphorus
could not be made to melt sharply at one temperature by any means
whatever.
To reach a still higher degree of purity the phosphorus in B was
almost entirely melted, and then made to erystallize again by slow
cooling ; when three quarters of the mass had solidified, the remaining
liquid was conveyed to C by tilting of the apparatus, and solidified
there by strong local cooling of the supercooled liquid (by means of
solid carbonic acid and aicohol).
This manipulation was repeated a great many times, in which the
mass remaining in &£ did not only get continually a higher melting-
point, but also beeame coarser and more perfectly erystalline.
When through this repeated partial crystallisation and removal of
the liquid four fifths of the quantity originally present in 2B was
conveyed into C, we filled the vessel A with the phosphorus which
had remained in BL by melting it in B, and by then making it flow
into A by tilting the apparatus.
By then sealing off at @ we broke the connection of the melting-
point-vessel with the other part of the apparatus, and the experi-
ment could begin.
The perfectly colourless coarsely crystalline phosphorus obtained in
this way now appeared te be so pure, that on immersion of the
melting puint-vessel in a thermostat the temperature of which varied
slowly, a melting-range was found smaller than 0.02°, so that we may
say that we have determined the unary melting-temperature of the
white phosphorus, for which we found 44,0°. Here we must remark
however that only the differences of temperature are exact to one
hundredth of a degree; the absolute values of the temperature may
perhaps need a small correction, as we used as a standard of tem-
perature a thermostat which had the température of 44° according
to a controlled normal thermometer.
When it had thus been proved that the phosphorus obtained by
us has the property of melting resp. solidifying in’a unary way, it
was examined in how far the complexity of the phosphorus betrayed
itself when we worked rapidly.
As the result can be most clearly demonstrated by curves of cooling
resp. of heating, we shall successively discuss figs. 2, 3, 4, and
5, which will give us a highly interesting insight into the inner
nature of the white phosphorus. *
Fig. 2 refers to the following experiment: the meltingpoint vessel
with white phosphorus was kept in a thermostat of 40° for a day,
and then suddenly transferred to a bath of 50°, after which the
temperature was read every 10 seconds by means of the galvano-
meter in a Wuparsrone bridge. Now it follows from the curve in
fig. 2, which indicates the temperature as a function of the time, that
the melting set in at 43,92°, and was completed at 48,96°.
The small range of melting temperatures of 0,04° shows that the
substance behaved in an almost unary way, but not perfectly so,
which is owing to this that the internal equilibrium bad set in at
4° under the unary melting-point.
In another experiment another course was taken. The melting-
point-vessel was kept for some time in a bath of + 46°, and then
taken from the bath to make the cooling take place under exposure
to the air.
As the phosphorus is very easily supercooled, the crystallisation
had to be started by grafting. For this purpose the capillary point
e of the meltingpoint-vessel was for a moment brought in contact
with solid carbonic acid and alcohol, when the temperature of the
1) In Fig. 2 the curve begins to rise nore slowly at 42°, because melting occurs
already im the outer layers of the phosphorus, which are warmer than the layer
in contact with the thermometer. If this was not the case, we should have cot
the dotted line and melting would not have appeared before 43.92.
At c the curve begins to rise more rapidly because the heterogeneous equili-
brium no longer sets in rapidly enough — in consequence of the small quantity
of solid substance present — that the heat applied to the solid substance is con-
sumed entirely in melting it. If this had been the case, the course would have
been also here as the dotted line indicates and the meiting would have beer
completed at 48°.96.
( 826 )
phosphorus had fallen below 44°, in consequence of which immediately
solid phosphorus formed in the capillary, which started the erystal-
lisation of the large mass, during which the temperature rose in
consequence of the heat of solidification. ;
The curve representing the result of this experiment has been
drawn in fig. 3. In this fig. @ denotes the point where the grafting
took place. Then the temperature fell to 4, after which it rose toe,
then it descended at first very slowly, then all of a sudden very
rapidly. The result is that also in this way of working the phosphorus
solidifies in an almost unary way, for the interval of solidification
amounts only to 0,05°, but in consequence of the comparatively large
difference of temperature with the surroundings the unary melting
temperature was no more to be reached.
In a third experiment which yielded a very important result, the
meltingpoint-vessel was first placed in boiling water for some time,
and then suddenly transferred to a bath of 15° to make the cooling
take place so rapidly that the internal equilibrium could certainly
not keep pace with it. When then grafting took place at about 43°.5
after taking out of the bath, the temperature rose above 44°, from
which, therefore, followed that when the cooling takes place very
rapidly the liqud phosphorus is already supercooled above 44°.
Therefure another time the grafiing took place above 44°, when the
temperature rose to 45°.5, and we sueceeded in getting a rise of
temperature to 46° with still earlier grafting, which, however, is by
no means the highest temperature to which the phosphorus can rise
in this way.
The eurve of cooling, obtained in one of these experiments, is
represented in fig. 4, and it is noteworthy how much ‘this curve,
which is the result of a perfectly analogous experiment to that to
which fig. 3 relates, apart from the previous history of the phosphorus,
differs from the curve in this last figure. The grafting took place
above 44° at about 44.°5; at first the temperature descended, then it
rose to 45°,05, after which it fell again, at first pretty rapidiy, then
iess rapidly and at last very rapidly again.
The whole line shows the type of a line of solidification of a
mixture, the melting-range is here about 1°.8, but can be considerably
larger still, which already follows from this that in one experiment
a temperature maximum was observed of 46°.
That the phosphorus which has been ill-treated in this way, and
at first unites to a distinctly visible conglomerate in the solid state
tries to reach internal equilibrium pretty rapidly, follows from fig. 5.
The curve traced in this figure is, namely, a curve of heating, which
(Ro27 4)
shows what has been observed after the solid substance obtained in the
previous experiment has been suddenly placed in a bath of 50°. The
curve of heating now shows that after some minutes a considerable
approach to the state of internal equilibrium has taken place, but
it has not been reached as yet, for the melting-range sti] amounts
to 0°.13, and the end-melting point lies above the unary melting-point
temperature.
Before proceeding to an interpretation of the observed phenomena,
we may point out here that, as Cuapman ') found that red P melts
to a perfectly colourless liquid, it has already been assumed in the
preceding communication, that the line for the internal liquid equi-
librium runs to the side of eP with rise of temperature *). If we do
so again here we are obliged, in contradiction to the 7’ Y-figure
given before. to draw a eutectic point in the pseudo-binary system,
as has been indicated in fig. 6, because only in this case the observed
phenomena can be explained *).
The line £/,/, denotes the internal equilibria in the liquids, and
sv refers to the internal equilibria in the solid white phosphorus,
so that s, and /, indicate the solid and the liquid phases which are
in internal equilibrium, and coexist at the unary melting-point of the
white phosphorus.
Now it follows from the course of the mentioned lines of equili-
brium, that when the liquid /, is cooled very rapidly, the erystalli-
sation can already occur at /,. Then in the absence of internal trans-
formations a melting-range /,/, would be found, whereas in case of
rapid heating of the solid phase » the melting will already begin
at s',, and be completed at /,, namely in case there are no inter-
nal conversions at all. The internal conversions, however, especially
when the two phases S and Z are in contact, proceed with fairly
great rapidity, and this is the reason, that a transeression of the
unary melting-point temperature is always much smaller than the
lines 7,7, and S's/'2 would lead us to expect.
Further the figure shows that the initial solidification resp. the
initial melting will appear the sooner according as a higher resp. a
lower temperature is started from, and thus we see that the new
theory of allotropy, given in our preceding paper, gives a natural
explanation of the observed phenomena‘).
1) Journ. chem. Soe 75, 743 (1899).
*) 2P is a substance we do not know, put of which we may assume with a
high degree of probability. that it is colourless.
5) It follows at the same time from this, thal we have not to deal with the
phenomenon of polymerism for the phosphorus (see preceding communication).
*) Rapid heating, from low temperatures, gives only a small change; so the
line 78, has a rather steep course.
( 828 )
.
We may finally remark here that Jonimois') thinks he has shown
with certainty that there are not fwo but three solid modifications
of the phosphorus, while, red, and pyromorjic phosphorus, which
last we shall call vo/e¢ phosphorus, as is more rational.
As Jonpois remarks it would also follow from his investigation
that the violet P is stable under 460°, above it, however, the red
modification, which melts to a colourless liquid at 610°.
When we accept these resulis it is the question how we can
account for the behaviour of the phosphorus in the light of the new
theory.
We might suppose that if three different solid modifications exist
of a substance, these three forms would have to be ascribed to
the existence of three different kinds of molecules.
This view has, accordingly, been advanced in the first communi-
cation, but if we think of substances with three, four, or more points
of transition, this supposition is somewhat improbable, aud as it
proves on further consideration not to be necessary, we prefer another
simpler and more plausible supposition for the present.
Also for the case that a substance occurs in three crystallized
modifications, the existence of two kinds of molecules can account
for the phenomena, namely, when we assume a second discontinuity
in the series of mixed erystals.
This has been done for the phosphorus in fig. 6; we see that the
liquids 6/ coexist with the mixed crystals ds’, the liquids /e being in
equilibrium with the mixed crystals se.
In this figure s, represents the red phosphorus at the unary melting-
point temperature. Below this temperature, which lies at 610° according
to Jotipors, the red phosphorus remains stable to 460°, at which
the red modification, which is denoted by s,, is converted to the
violet S,, which is therefore stable below 460°.
We may further remark that as red 7? is obtained on a mann-
facturing scale from yellow P by heating to 280°, the line /,/, must
be left and the line s,s',, reached, which however, is also still meta-
stable, and that then, as JoniBots found, by means of the catalytic agent
Jodium, the stable state at that temperature, the violet ? is obtained,
which lies on the line sq.
The second substance which was examined as to its complexity,
was mercury. As only one crystallised state is known of this sub-
stance, and as not one of its properties betrays a complex character,
') Comptes Rendus 149, 287 (1909).
F , 151, 382 (1910).
( 820 )
it was supposed that this substance would always behave ina unary
way. Experiment has fully confirmed this conjecture. Whether mer-
eury was suddenly cooled by water in vacuo from + 800°, and
then by solid carbonic acid and alcohol, or whether it was rapidly
heated from 80, the point of solidification, resp. melting-point always
remained the same, and the substance perfectly behaved as a unary
one, from which we may therefore draw the conclusion that when
the substance is complex the internal transformations must proceed
with extraordinarily great rapidity, or what is more probable that
mercury really consists of one kind of molecules.
The third substance examined by us, for which in view of its
transition points, the same was expected as for the phosphorus,
was tin.
Though the investigation made bears as yet still a preliminary
character, we may yet communicate that tin of particularly great
purity can solidify entirely as a unary substance, but that it
betrays its complex character when the experiment is made very
rapidly, just as phosphorus does. In a following communication we
hope briefly to communicate the result of the final investigation.
Amsterdam, December 23° 1910.
Anorg. Chem. Lab. of ihe University.
Chemistry. “On the determination of threephase pressures in. the
system hydrogen sulphide +- water.” By Dr. F. E. C. Scurrrrr.
(Communicated by Prof. A. F. Hotrteman).
I. In the investigation of the systems in which hydrogen sulphide
is one of the components, the difficulty presents itself that a chemical
action can affect the mercury that shuts off the mixture, when it is
not sufficiently purified from admixtures. This action will chiefly be
due to the presence of slight quantities of air. By excluding the
presence of air (and water), as completely as was possible in the
methods used, I sueceeded before in determining the situation of the
three-phase curves in the system hydrogen sulphide -/ ammoniac.
The methods used in the investigation, had to be adapted to
high pressures, as it was my principal aim to determine the points
of intersection of the critical line and the three-phase curves, the
eritical end-points. In this [ have at the same time found an oppor-
tunity to determine the shape of the spacial figure of the mentioned
system at lower temperature; the observations at these low tempe-
( SBO )
ratures and the low three-phase pressures corresponding with them
though perfectly sufficient qualitatively, could of course lay claim
to but little accuracy, particularly because the pressures were read
on a metal manometer, which indicated up to 250 atmospheres, and
which can give only rough values below about 20 atmospheres, and
because the slow setting in of equilibrium can cause a great relative
error at these low pressures.
I have now tried to find an improved method for the investigation
at pressures below 20 atmospheres, which could yield more accurate
results. I intend to give here a description of this method and to
demonstrate its efficiency not by the aid of the system hydrogen
sulphide +- ammoniac, as this would only involve a_ repetition
of former observations, which would not open new vistas"), but
apply this method to another system with hydrogen sulphide as
component, namely the system hydrogen sulphide ++ water. As will
appear from the following description, mercury is not affected by
moist hydrogen sulphide, at least below 30°, when presence of air
is carefully excluded.
2. Preparation of the mixtures.
For the preparation of a hydrogen sulphide + water mixture the
Fig. 1.
1) These observations will shortly appear in the Zeitschrift fiir physikalische
Chemie. 1t may only be remarked here that action of hydrogen sulphide on
mereury was no longer observed, and that e.g. reduction of the volume under
three-phase pressure to half its size, gave an increase of pressure, which eenerally
amounted to less, but in one ease to slightly more than 0,1 atmosphere; these
deviations are about as great as the errors of observation.
( 831 )
apparatus was used, represented in figure 1. The hydrogen sulphide
was prepared from a solution of natrium sulphide, which was free
from carbonic acid and diluted sulphuric acid; the former solution
was obtained by saturating natron, which had been freed from
its carbonic acid by the addition of barium hydroxide, with hydrogen
sulphide. The gas prepared in this way was dried by phosphoric
anhydride, and led into the exhausted vessel 46 through the cock
A (fig. 1); it was then freed from air by condensation in O by
means of the two vessels ?, and ?,, which were filled with carbon
of cocoa-nut; 9, P?,, and P, had been placed in liquid air for this
purpose. If now there were no discharges at all in the GrissLEr
tube V, the hydrogen sulphide was again conveyed from (0 into
the reservoir £6 by evaporation. Then the gas which had remained
in the tubes of the apparatus between J/ and Z could be sucked
off by means of a water-jet-pump, when the cock C was opened.
The Cailletet tube, which was made of common glass for this
experiment, where the pressures did not exceed 25 atmospheres, and
which could have a comparatively large bore (5 mm.), was sealed
to a glass spring /£, and thus connected with the apparatus.
Now a quantity of mercury freed from air by boiling which
was sufficient to fill the entire test-tube D, was brought into the
reservoir #7 through G. After G had been sealed, /” was provided
with a little distilled water, and the upper end of this tube was
also sealed. Now the water in / was frozen, and the test-tube
was evacuated by means of the water-jet-pump (cock C’) and carbon
(Ff, and P.,). After the cock 4 had been closed, the water could
now be distilled over from /' to the upper end of the test-tube,
which had been cooled with liquid air (vessel S).
A quantity of hydrogen sulphide was admitted from 4 into the
apparatus between J/ and / with open vessel O; by means of the
manometer J/, whose rightside leg had been evacuated, this quantity
-could be roughly estimated. This gas too was solidified in the upper
end of the test-tube when / was opened.
When I had then convinced myself that no aw was present im
the test-tube (discharge in .V), the Cailletet tube was tilted, in con-
sequence of which the mercury flowed from H into the U-shaped
lower end of the test-tube, and was forced up to the top of the test-
tube by the air in consequence of the opening of the cocks C’ and
L. Now the Cailletet tube was separated from the apparatus at K,
and placed in the pressure cylinder which was filled with mereury
purified and freed from air by boiling.
When we work in this way the presence of air is practically
54
Proceedings Royal Acad. Amsterdam, Vol. XIII.
( 832 )
excluded and the mixture is only in contact with a small quantity
of pure mereury; so contact with not entirely air-free meveury and
rubber joints are entirely avoided in this way.
3. Determination of pressure and temperature. A cylindric vessel
conically narrowed at the lower end was fastened to the Cailletet-
tube by means of a cork, and filled with water. The heating took
place electrically; the temperature was regulated by means of an
incandescent lamp resistance, and read on an Anschiitzthermometer,
which had been compared with a normal thermometer. The stirring
took place in the waterbath by means of lead plates, which moved
vertically up and down, in the test tube by means of a KUENEN
stirrer; the electromagnetic coil required for this was vertically moved
round the heating-vessel.
For the determination of the pressure I used two air-manometers,
one of which indicated a minimum pressure of about 38, the other
of about 8 atmospheres. The errors of the method remain in this way
below 0°.1 and 0.1 atmosphere (errors of the manometer and difference
of position between the mercury in the test tube resp. manometer
and in the pressure cylinder); the errors which can be made in the
determination of the three phase curves, may be generally estimated
at about 0.1 atmosphere, as appears from the concordance of the
results. I shall, however, return to this, when discussing the results.
4. Results. In fig. 2 the P-7-projection of the spacial figure is
represented. In the first place we see drawn in it the vapour-pres-
sure curve of hydrogen sulphide, which had been determined before
by many observers. Just as in my previous determinations concern-
ing the system hydrogen sulphide + ammoniae I arrived again at the
result that the values given by Reenavir, are too high; in the range
of temperature investigated by me the deviations vary between 0.8
and more than one atmosphere. The only value which was deter-
mined by Oxszewski in the range examined by me, presents a
deviation of less than 0.1 atmosphere from mine, and has been denoted
by QO in the graphical representation; Rrexavir’s deviating values
I have omitted in the figure for the sake of clearness.
The hydrogen sulphide showed a variation of pressure of less
than O.1 atmosphere on isothermal compression to a fourth of the
total volume, while also the pressure at which the last quantity of
vapour disappeared differed less than 0.1 atmosphere from that at
the greatest possible volume.
Immediately below this line two three phase curves appear in
the /-7-projection, one of which indicates the coexistence of the
hydrogen sulphide hydrate by the side of vapour and a liquid rich
—_—
==
( 833 )
in hydrogen sulphide, and the second the equilibria between two
liquid layers and vapour. ‘The former three-phase curve (S/,() gives
an
15 20 25 30 7
Hig 2.
stable states all over its course; the other (1,4,G) metastable states
below 29.5°, above this stable equilibria. The isothermal differences
of pressure between these two three-phase curves and the above-
mentioned boiling-point curve of hydrogen sulphide, are very slight,
and are near the errors of observation, as regards their order of
magnitude. Still I think I am justified in concluding with certainty
from the great number of observations given in the table that the
pressures are greater on the three-phase curve S/,G° than on
L,L,G, and that the boiling-point line of hydrogen sulphide lies
higher than either.
Also looked upon from a theoretical point of view this order
( 834 )
seems the most probable one; for if the liquid-vapour surface of the
hydrogen sulphide continually descends to the side of the water, the
three-phase pressures will lie below the maximum tension of liquid
hydrogen sulphide at a certain temperature, and (below 29.5°) the
metastable 1,4,G' curve will have to lie lower than the stable SL, G-
curve. We can see this, among others, already from this that for
the coexistence L,4,G, the liquid ,, being metastable, must be
super-saturate with respect to the hydrate, and so richer in water
than the liquid Z, on the three-phase curve SL,G.
LG (pS) L\LyG SL,G ! SL.G
7 (i [2 |
| |
15 16.38R |
15.8 | 45.94 | 19.4| 47.3 [17.4 [16.6 [15.5 | | 6.6C
15.9 |16.0—; 16.04} 19.8 | 47.4 [18.4 147.0-16.3 [5.3—
16.0 16.0 20.6) 47.8— |[18.7 |17.05 |{t7.5 | | 5.8F
16.2 16.1 | 90.8] 417.9— |li9.0 17.9 Ni7.9 |6.3—
47.04) 16.5- | 91.2 |418.0;180 {19.9 47.6—18.4 | 725G
17.6 || 467 | 21.4 |48.45;18.2|20.9 |48.0—19.7 17.6 |
17.8 |16.8—; 16.8— 22.8| 48.85 |lot.2 48.444)19.8 | TAF
18.2 '46.950)93.0| 18.95 [1.8 \1s.44¢to1.0 ig.64
19.0 Vie | 23.65) 19.3— |p2.9 48.94/109.8 | 11.0C
2 | 148.62 R24.6 | 19.74 [193.65 |19.3 |]23.0 9.2F
20.4) 47.9-4- 24.8 |19.85;19.8-1123.8 19.35 |93.3 10.7
2 18.95 | 2A | 20.0— [24.1 |19.54]24.84 19.9 |
22.0 18.65 25.4 | 20.0— |26.0 |20.5 125.0 | MF ; 16C
93.6 | 19.41 5.6 | 20.1— [6.6 j20.7-125.6 |14.0-|
24.9 |20.04; 20.4— 95.8 |20.2;20,3—\107.2 |21.04}o7.4 [17.4
5 | a1.o7Rbo.4 90.6 /27.34)21.05 |28.5 [19.5416 F
5.441 20.3— l6.9 £0.75 |8.2 jat.5t{9.9 j21.34
5.8 | 90.5— 27.5 | 2.04 |8.8 |21.8
26.1 20.64 98.0) 21.3— |lo9.4 |92.4 SLL,
26.2 20.7— 98.2 | 24.4 Tr P
97.5 2.3 108.4) 21.54 —- a
29.6 99,35 99.1 | 941.75 29.8 | 32
30 | 93.73 R)29.2 | 21.9— Gliadnanlenant
30.6 | 22.9 | (30.3 | 92.45 799.5; PWA+4
31.6 93.44 31.0 | 99.9— :
31.6 23.45 31.2} 229-1 R = REGNAULT
38.4 | 94.45 320 | 93.4 O = OLSZEWSKI
39.7 | 93.84 C = CAaILtetet and BorDET
33.2 | 24.046 F = DE Forcranp
( 835 )
The possibility that on the liquid-vapour plane a line of maximum
pressure occurs, cannot be excluded beforehand, of course, more
especially because in this system a compound occurs, and moreover,
one of the components (//,() is certainly abnormal. It seems even
still possible here, that immediately on the hydrogen sulphide side
such a line of maximum pressure occurs; then it must lie, however,
at coneentrations which are smaller than the gas and liquid con-
centrations on both the three-phase curves. This, however, does not
seem probable for the present, and so I have not taken it into
consideration in the /?-7-section (fig. 3).
The two three-phase curves SL,G@ and L,4,G@ intersect in the
quadruple point (29.5°; 22.1 atm.); the two other three-phase curves
which pass through this point, where resp. solid hydrate occurs by
the side of two liquid layers (SZ,/,) and by the side of vapour
and liquid rich in water SL,G, have also been represented in the
graphical representation.
The preceding table gives a survey of the observations of the
discussed lines of equilibrium.
5. By the aid of the above data, a P-v-section has been given
schematically in’ fig. 8, which has
been drawn through the spacial
figure for about 20°. In this we
have assumed, as was mentioned
above, that the liquid-vapour sur-
face descends continually from the
first to the second component; the
point «, the maximum tension of
liquid hydrogen sulphide lies higher
than the stabie three-phase curve
S L, G (b) and the metastable
LL, G(e)*). The other equilibrium
curves and the regions given in
the figure do not call for a further
explanation. I will only draw_ at-
tention to the faet that the hydrate
in this seetion can ne longer occur
stable below the three-phase curve
HS x TiO oe an ta En
SL, G(d); tor with isothermal in-
Fig. 3. crease of volume the transformation
S+sL+ G occurs on this three-phase curve, in other words, the
1) All the metastable lines of equilibrium lave been indicated by dotted lines.
( 836 )
hydrate evaporates and melts. Then it will be clear at the same
time that the earlier observations of pw FororaNnp *) and of Cartierur
and Borper*) refer to this three-phase curve, as they have determined
pressures which were necessary for the formation of hydrate ; then
it becomes also clear that this pressure as br FoRCRAND points out,
is independent of the concentration of the mixture, which is, indeed
required for this three-phase equilibrium by the phase rule.*) L have
indicated their observations by the figures Cand / both in the table
under S “4, G and in the ?-7-projection of fig. 2. My observations
appear to lie between them. The pretty large deviations between the
three lines must, in my opinion be aseribed to this, that the formation
of the hydrate in case of compression, and the melting in case
of expansion takes place slowly; in the first case we tind too
low, in the second too high pressure. | have made my observations
of these three-phase equilibria by slowly heating at constant
pressure, and by determining the temperature at which the trans-
formation S+L+G occurred. This method of working appeared
to yield more accurate results than that in which the transformations
were observed for isothermal change of volume.
Whereas the equilibria on the other three phase curves establish
themselves spontaneously at constayt temperature, and the deviations
rarely exceed O.1 atmosphere, I think I shall have to estimate the
accuracy of the observations on the lines SL,G and SL,L, at 01
to 0.2° *).
In the P-2-section the gasphase ( and the liquid phase ZL, lie
on the three-phase-curves on the hydrogen sulphide side; now it
appeared from some preliminary experiments that the liquid phase
L, lies near the water side, in other words that the region of non-
miscibility extends over almost the full width of the figure.
Finally a few remarks may be made on the composition of the
hydrate. It is not to be derived with certainty from the literature
on the subject. Dr Forcranp, who has made numerous analyses of
hydrate, considered successively H,S.15H,O, H,S.12H,0, and H,S.7H,O
the most probable formula. He justly ascribes the very bad agree-
ment of the analysis results to the fact that the hydrate easily
1) pE ForcrAnb. Gr. 94, 967 (1882); pr ForcRaND and VILLARD Cr, 106,
849 (1888).
2) GAILLETET and BorpeEt. C.r. 95, 58 (1882).
3) pE ForcrRAND. C.r. 94, 967 (1889).
') Also the observation of SZ, Ly took place by the determination of the tem-
peralure at which the transformation S— L,-+ Lg is found with slow heating at
constant pressure.
‘
:
;
'
;
( 837 )
retains water. When we further bear in mind that the hydrate is
only constant below 0.85° under atmospheric pressure, and that,
accordingly, formation of the hydrate at atmospheric pressure without
formation of ice will only be possible between O° and 0.35°, it will
be clear that we must here have recourse to special methods of
analysis. I shall have to postpone a description of a method suitable
for this purpose to a fellowing communication; it may only be
mentioned here that even the formula H,S.6H,O derived later by
DE ForcraNp on theoretical grounds probably still contains too great
a quantity of water.
(February 23, 1911).
‘\
ee
KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN
TE AMSTERDAM.
PROCEEDINGS OF THE MEETING
of Saturday February 25, 1911.
Ce
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige
Afdeeling van Zaterdag 25 Februari 1911, Dl. XIX).
S. L. Scuouren: “Pure cultures from a single cell, isolated under the microscope”. (Commu—
nicated by Prof. F. A. F. C. Went), p. 840. (With one plate).
J.C. Kruyver: “On the integrating of series term-by-term”, p. 850.
L. 5S. Orystem: “Some remarks on the mechanical foundation of thermodynamics”. 11. (Com-
municated by Prof. H. A. Lorentz), p. 858.
Pu. Konnstamm and J. Timmermans: “On vapour-pressures in binary systems with partial
miscibility of the liquids”. (Communicated by Prof. J. D. vay per Waats), p. 865.
W. H. Junius: “Selective absorption and anomalous scattering of light in extensive masses
of gas”, p. 881.
W. G. Huer: “Notes on the trochlear and oculomotor nuclei and the trochlear root in the
lower vertebrates”. (Communicated by Prof. L. Bork), p. 897. (With one plate).
J. H. F. Komrsrueee: “Acetifying air- and ricebacteria the cause of Polyneuritis gallinazum”.
(Communicated by Prof. C. H. H. Spronen), p. 904.
F. L. Bercansivs: “A new accurate formula for the computation of the self-inductance of a
long coil wound with any number of layers”. (Communicated by Prof. W. H. Jurivs), p. 917.
H. J. Wameurcer and BP. Busanovic: “On the permeability of red bloodeorpuscles in physio-
logical conditions, more especially to alkali- and earth-alkalimetals”, p. 927.
C. Winker: “A tumour in the pulvinar thalami optici. A contribution to the knowledge of
the vision of forms”, p. 928. (With one plate).
E. Maruias and H. Kamerrincu Onnes: “The rectilinear diameter for oxygen”, p. 939. (With
3 plates).
A. F. Horreman, J. C. Harrocs and T. van per Linpen: “The nitration of aniline and of
some anilides”, p. 956.
Pu. Kounstamm and J. Timmermans: “Addendum”, p. 957.
Proceedings Royal Acad. Amsterdam. Vol. XIII.
(840 )
Microbiology. “Pure cultures from a single cell, isolated under
the microscope.” By Dr. 5. li. Scnourun. (Communicated by
Prof. F. A. F. C. Went).
(Communicated in the Meeting of December 24, 1910).
In 1899 I demonstrated at the Scientific and Medical Congress at
Haarlem?) a method which I had discovered for isolating a single
cell under the microscope, which method, worked out further and
applied, appeared in 1901 in these Proceedings*) and also formed
the subject of my dissertation*). Since then I have continued my
experiments in this direction. In 1905 T again*) published improve-
menis of the method, with further applications and now, 5 years
later, the method has again been so much improved and simplified
in several respects that I feel a communication should no longer
be deferred.
While referring for particulars to my last publication, which,
apart from the alterations about to be deseribed, may still serve as
description, I wish here to outline the method in brief and then to
mention the improvements.
On a coverslip which has been smeared with a little vaseline and
then passed through a flame, a drop of the material is placed from
which it is desired to isolate a cell. At a distance of about 3 mm.
opposite drops are put, in whieh it is desired to grow the pure
culture. The coverslip is then placed on a moist chamber on the
microscope stage. The left lateral wall of this chamber is provided
with a horizontal slit, which is closed by a viseid fluid and through
which a glass needle projects, bent at its end into a loop. By means
of a simple mechanism the needle can turn round a support so that
its end can touch the lower surface of the coverslip. A mechanical
stage renders it possible to do this in any part of the field.
The space in the moist chamber is kept saturated with water
vapour by a drop on the floor. The vapour condenses on the lower
surface of the coverslip, and since the latter has heen treated with
1) Een methode voor het maken van reinculturen, uitgaande van é€n onder het
microscoop geisoleerde cel”. Handelingen v/h. Te Nederl. Nat. en Gen. Congres,
gehouden te Haarlem 1899.
*) “On pure cultures of Saprolegniaceeén”. These Proceedings March 30, 1901.
5) Reinkulturen uit eén onder het mikroskoop geisoleerde cel. Proefschrift.
Utrecht 1901.
*) Reinkulturen aus einer unter dem Mikroskop isolierten Zelle. Zeilschr. fiir
wiss. Mikr. und fiir mikr. Technik, Bd. XXIL 1905 p. 10.
| pe
(S41 )
vaseline, the condensation takes place in small rounded droplets,
which do not coalesce. Before use the needle is sterilized in a
manner to be hereafter described. A micro-organism to be isolated
is now sought at the edge of the so-called material-drop. The needle
is moved up so that the end touches the edge of the drop near the
cell that is to be isolated.
Then, when the moist chamber is moved sideways the cell with
a tiny droplet will be drawn out of the large drop. This cell is
now taken up in the eyelet of the needle. This eye is then brought
down somewhat so that it no longer touches the coverslip, and
then the moist chamber is moved sideways, under a low power, so
that the eyelet, by an upward movement, comes near to the edge
of one of the sterile drops and deposits the isolated cell, in a small
drop, once more on the coverslip
Under the high power this small drop with the cell is moved
into the sterile drop, in which the culture is to be made, the so-
called culture-drop. —
The glass is then placed on an ordinary moist chamber which is
kept at the required temperature. If the culture drop is so/id, then
the colony grows on its edge, and with the strongest power its
development can be followed from the beginning. If the eulture
drop is jluid the colony generally spreads itself over the whole drop.
So much for an outline of the method.
Of the improvements made since my last publication, [| mention in
the first place, that instead of the isolation apparatus hitherto made
by the firm of D. B. KaGenaar Sr. in Utrecht for £ 5. (without
needles) I have constructed a simplified arrangement, of which the
price with three isolation needles amounts to £2. 1.8. The objection
that the needles were not obtainable commercially is thus removed.
Formerly [ used one pointed needle, and three ending in an eye:
one very small eye of 9m in diameter, a medium one of 30 u, and
a large one of 50 diameter. Experience has shown me, that the
smallest eye, which was the most difficult to manufucture, must be
abandoned. It was intended for the isolation of bacteria; with a
somewhat greater eye this succeeds much better, and the following
3 needles suffice: a pointed one, an eye of about 30 in diameter
for bacteria and small yeast cells or spores and an eye of + 504
in external diameter for larger. cells ’).
With the older apparatus there was a needle at. each side of the
1) The above mentioned measurements are average values; the diameter and
thickness of thread can, without objection, be somewhat larger or smaller.
5 5*
( 842 )
Inicroscope; with one the cell was isolated, and set down close to
the culture-drop, and with the other, i.e. always the pointed needle,
the cell was placed in the culture-drop.
The original intention of this was as follows: if it should happen
that sometimes a second cell is introduced into the eye of the needle
in addition to the one that is to be isolated, this one perhaps might
be released unnoticed and could enter the drop together with the
cell to be isolated. This mistake can however be avoided if the
latter transference to the culture-drop is effected by means of the
second needle, which is known to be sterile.
In the meantime | have learnt from experience that in many cases
the whole operation can very well be carried out with one needle,
in which ease the cells of the material must occur so isolated from
each other that one cell can easily be taken up without another
accompanying it.
On that account the simplified apparatus has only one needle-
holder, to the left of the microscope. No general rule can however
be made, and I intend to return to this later.
In the other arrangement the microscope stands on a plate which
can be moved in 4 directions by means of 2 screws: one always
begins with the microscope so placed that the needle, when it
touches the glass, comes into the middle of the field of vision.
In the simplified apparatus this plate, although convenient in
practice, is left out, on account of expense; therefore the miscroscope
is adjusted by hand and by tapping with the finger-tip (by which
means very slight displacements are obtained).
The needle-holders can be adjusted for microscope stages of
various heights.
In the years since my last publication 1 have gained much other
experience which I may add.
Firstly, with special regard to bacteria: one should isolate from
material which is as young as possible. Recent experiments have
clearly shown that bacteria in a culture very quickly die. The curve
of growth which is obtained with the times as abscissae and the
bacteria as ordinates, rises quickly and then falls quickly. In cholera,
at 37° for example it already reaches a maximum after 12 hours.
In older cultures therefore there is a greater chance of isolating
weak individuals, which then produce no colony. |
Further, at the time of isolating unnecessarily long illuminations
must be avoided. Since however in this method the light must
be fairly strong, particularly in a power of 1000 times, it is
best to work with artificial light, for instance with incandescent
light from which the chemieally active rays of ultra violet have
been eliminated off. For this purpose the well known glass
bulb is used; in this case it is not filled with ammoniacal copper
oxide but with a not too dark solution of potassium dichromate (1
gram suffices for a globe of 3.5 litres). If one wishes somewhat to
sofien the yellow light, which according to some is harmful, to_ the
eyes, this can be done by placing a thin cobalt blue glass on the
iris-diaphragm.
Other important improvements are connected with the use of the
moist chamber on which the coverslip is placed after the actual
isolation has been accomplished.
On consulting the handbooks on the method of making the so-
called drop-cultures in moist chambers, one gets in general the impression
that such cultures must invariably succeed. For years I knew uo
better, and attributed the miscarriage of many of the cultures I made
to faults in my method of work, until I found in Kiisrer’s “Kultur
der Mikroorganismen” on p. 54 the statement that all kinds of factors
may here operate unfavourably. And when with reference to the
‘papers quoted there, I read among others the broadly conceived and
carefully executed experiments of CLark and of DuGear’*), [saw that
they had had the same experience as myself. CLARK comes to the
conclusion that some micro-organisms are sensitive even to slight
differences in the concentration of the culture-drop, or to the vapour
pressure inside the moist chamber. On the floor of the latter he places
no drops of water but some drops of the same fluid in which the
culture is grown. Then the vapour-pressure of the culture-drop and
of the drops on the floor will be the same, and therefore there can
be no reason for the culture-drop taking up or giving off water
vapour, by means of which the concentration is altered. Since the
rise of temperature in the closed space ef the moist chamber is also
detrimental, Crark did not at once wholly close it with the cover-slip
on placing it in the incubator, but left a small slit, which was
afterwards closed. Further Criark used relatively large moist chambers,
for instance, a glass cylinder of 17'/, mm. in external diameter and
10.7 mm. in height. Attention should be paid to these suggestions,
as far as is possible, and also the cleaning of the cover-slip on which
the investigators above-mentioned lay special stress is not to be
1) J. F. Cuark, On the toxic effect of deleterious agents on the germination and
development of certain filamentous Fungi. Bot. Gazette 1899. vol. 28. p. 289.
B. M. Duaear, Physiological studies with reference to the germination of certain
fungus spores. Bot. Gazette. 1901. vol. 31 p. 38.
2) lic. p. 204.
( S44 )
considered as of secondary importance. The cover-slips must be fairly
new, at any rate not so old as to show signs of weathering (micro-
scopically to be recognised as small scratches, — an appearance
also given, however, by some impurities). Chark and Duacar deseribe
in detail their method of cleaning; | myself boil them about 10 min.
in a soap-solution, then they are well rinsed in plenty of ordinary
water, preferably separately, and are stored dry. Other methods of
cleansing, such as in the well-known mixture of potassium dichromate
or in aether, can of course precede, if necessary, this boiling in a
soap-solution,
Only by using good cover-slips can sharply defined drops be
obtained. Further the slips must a short time before isolation be
smeared with vaseline; if this is done some days before, then the
drops are not so good. The diluting of the material is an important
factor. The best and simplest method I found to consist in’ placing
a very large drop of fluid on an ordinary cover-slip which has been
prepared with vaseline.
This can be done much better than with the eye of a
needle, by using a strip of platinum foil += 5 ¢@m. in length,
+ 2'/, mm. in breadth, which is bent longitudinally at right
angles into a small gutter and which is further treated as an ordinary
inoculation needle. About this drop one need not be so particular,
as it is a large one; some material is introduced into it, and
there distributed. If too much has been introduced some may be
removed by the gutter-needle and then liquid is again added. The
material drops are taken out for the purpose of isolation, and it is
preserved, when necessary, in a moist chamber.
In my last publication I stated that the material drops should
always consist of physiological sodium chloride solution, because then
the isolated droplet separates most readily from the large drop. In
my later experiments I found that some other fluid may also be
used for the purpose, although they are slightly less suitable ; such
are meat broth, glucose-peptone for yeast and moulds. ete.
Finally a few hints and improvements may be mentioned.
By capillarity particles of vaseline and bacteria may sometimes
dry on the ends of the isolating needles, especially if they are not
cleaned immediately after use. In this case mere dipping into sulphuric
acid is not enough; it is best first to wash the ends with ether,
then to keep them for a quarter of an hour in concentrated sulphurie
acid heated to 100° on a water bath.
The slit in the isolated chamber, through which the needle projects,
is closed with liquid paraffin, thickened with a little finely divided
=~
. ( 845 )
vaseline; this is preferable to thickened olive oil and diapalm, as
previously indicated.
The coverslips are not fastened to the moist chambers by means
of vaseline, but by a mixture of 20 volumes of vaseline with 1 volume
of paraffin, which can resist a temperature of 37° without melting.
I should gladly have limited myself to the above as regards the
technique of my method, had I not thought it necessary to add
some remarks concerning a paper by Mr. A. W. Nipuwenntts, in
the Proceedings of the meeting of Nov. 26 last, entitled: “Method for
erowing micro-organisms out of a single cell”. I will not refer to
the principal features of the method, as they are quite the same as
those of my own. I only propose to consider the objections, which
NIbUWENHUIS raises against my method, and the modifications which
he has hence thought necessary to introduce into the more delicate
manipulations.
NigvWENAUIs applies four tests to an isolation method and says
there is no -method satisfying these tests. The first of these is that
isolations can be carried out at magnifications of 300 and higher
(N. uses magnifications of 800 and 350). My method of course complies
with this test, for all my isolation experiments with bacteria were
carried out with a */,, oil immersion Lutz, therefore at a magnification
of about 1000.
The second test is that the organism to be isolated should not be
harmed by either chemical or physical stimuli. As regards chemical
stimuli, Nisuwennuis asserts, that when my eye-shaped needles have
been desinfected with sulphuric acid and ammonia, substances remain
behind which irritate the cells, and that I myself give the proof of
this, on p. 113 of my dissertation. In reality however I pointed out
there, that this is only the case if the sterilisation is not conducted
properly, i.e. if the needles are placed more deeply in the sulphuric
acid than in the ammonia, so that the superfluous acid ascends
towards the point of the needle. | added explicitly: ‘When I again
“isolated the bacterium, while avoiding these mistakes, its power of
“liquefaction was found equally strong after the isolation. The absence
“of growth of the colonies then caused no more trouble”. That this
sterilisation should have harmful consequences, | have never been
able to discover, although I have specially investigated the question
by making parallel experiments with sterilized and non-sterilized
isolation needles. Moreover the needle is always washed before use
in a sterile drop on the isolation coverslip, and beforehand the
needle may be held for a moment in a tube with sterile water at
100°, in which any trace of ammonium sulphate, should it have
( 846 )
remained behind, dissolves very rapidly. [ do not however, believe
that this salt ever remains behind, for one always finally dips into
excess Of ammonia, and this evaporates in a few seconds. No mention
is further made of harmful physica’ stimuli; we can therefore leave
them out of account. [will merely observe now that in dragging
the isolated cell across as I did originally (see my dissertation) and
as Ninuwennvts still does, there is a greater danger than in carrying
it across according to my method (see below).
The third test which my method is not supposed to satisfy, is
that of the greatest possible simplicity, so that the modus operandi
is within the reach of every investigator. This seems indeed to be
the gravest objection, for at the beginning of his paper Nrmuwenuuis
disposes of my method as pretty well useless. “It is — so he says
there much too complex for a general application, as it requires
too much from the dexterity and patience of the investigator on
account of the long time too, wanted in the application it would
be troublesome even for a skilful experimentor, frequently to use it”.
As regards this point, | cannot do better than quote my conclusion
in my last paper’): durch einige Uebung bringt man es bald so
weit, dass, wenn das Material ungefiihr die richtige Verdiinning
hat.... man in ungefahr 5 Minuten eine Bakterie aus den Material-
tropfen isoliert und in den Kulturtropfen bringt”. And this applies
to bacteria; fungus spores and yeast cells are treated still more
easily. Experience has moreover taught me that anyone who is quite
new to the method, acquires it as rapidly as the methods for staining
spores or cilia.
The fourth test, that asepsis should be easily maintained, is not
further advanced as an objection to my method. Perhaps Nikuwenntis
is thinking here of my moist chambers which I do not pass through
a flame each time, but which are internally coated with vaseline.
In the hundreds of experiments which have gone through my hands,
I have never observed a single case of infection ; the vaseline retains
the organisms which fall on it, and the latter do not germinate.
With reference to the above demand for simplicity, it might be
pointed out that there is yet another objection to my method: the
difficulty of making the glass needles. Certainly Nimuwrnuuts’ needles
are made more easily. In my last paper I mentioned however, on
p. 18, that, so long as the method of manufacture had not yet been
published, IT would gladly personally help any one, who desired it.
| wrote: “Eventuelle Anfragen werde ich indessen vorlaiufig gern
entgegennehmen”. And this I have always done disinterestedly —
1) p. 26.
S. L. SCHOUTEN. ‘Pure cultures from a single cell, isolated
under the microscope.”
Apparatus for isolating a single cell.
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 847 )
when my own countrymen were concerned — also for instance when
Mr. Niruwensuis began to work with my method. Moreover I have
published the method of making the needles, and have pointed out
that any one can easily make the simple mechanism required *).
Meanwhile I emphasise, that this has nothing to do with the
modus operandi of the method. One can hardly for instance eall the
modus operandi of telephoning complicated, because the manufacture
of the telephone mechanism is difficult.
So much as regards the objections to my method, of which I
appreciate the last one — the difficulty of making the glass needles
and the fact that they could not be obtained commercially; 1 am
therefore all the more glad that this objection has been removed.
I now wish to discuss the alterations introduced by Nieuwennurs
in my method.
Fearing the above mentioned imaginary danger in sterilising the
isolation needles, Nreuwennuis has preferred to make for each isola-
tion a new needle which terminates in a globule instead of an
eye and which must be fastened into the needle-holder by means of
plaster of Paris. It seems unnecessary to show that this is much
more cumbrous than working continually with the same needle,
which, when necessary, is readily sterilized in the way described.
One can work for years with a single needle: it is elastie and does
not break unless it is knocked roughly or dropped.
Niguwennuis has the needle fixed to a support stand, which stands
separately next to the microscope, while in my apparatus the
support and microscope stand on the same plate, so that a displace-
ment of the support with respect to the microscope, for instance
through a knock, is rendered impossible. In the support used by
Nizuwennvts, the needle can be moved in 8 directions, which is
quite superfluous if a mechanical stage is used, as I have done from
the beginning. Meanwhile Nimowrnnuis (p. 533) eventually came to
the same conclusion. He further places the coverslip, in which the
cell is to be isolated, under the microscope in a kind of chamber,
which is quite open on one side in order to admit the isolation
needle. In my apparatus the needle enters through a slit, which is
closed with liquid paraffin. By this means a closed moist chamber is
formed, which has the great advantage, that if a drop is placed on
its floor, even the smallest isolated droplet does not evaporate, so
that observations can be made on isolated cells for a whole day,
1) Zeitschr. fiir wiss. Mikr. Technik Bnd. 24, 1907, p. 258. Burry — in his
_*Tuscheverfahren’”” wrongly assumes that the price of this simple mechanism is
100 Mk, which is the price of the apparatus for isolation.
( 848 )
if necessary. That asepsis is better secured by this arrangement than
by the chamber of Nimuwennvis, which is 8 m.m. high and quite
open on one side, requires no further proof.
My principal objection is, however, to the circumstance, that
Ninuwennuis drags the isolated cell in the droplet over the glass to
the culture drop. This he cannot avoid, as he uses a elub shaped
needle.
In my dissertation I also transferred the cells by dragging, but,
years. One
of the reasons, which certainly may be advanced, is that this
with a few exceptions, I have departed from this in later )
dragging, in the case of very small cells, fatigues the eye. The
principal reason, however, is that the cells remain behind, especially
in the case of long thin rodlike bacteria, spirillae, and spirochaetes.
There are all sorts of cells which it is not possible to drag across,
even in a large transport drop; such a drop has further the
disadvantage that a contaminating bacterium is not readily dis-
covered in it. Nipuwnnnuts states, that with him even spores some-
times adhere to the lower surface of the coverslip. No wonder,
especially if one further considers that the isolated droplet begins to
evaporate in its journey across the chamber, which is open on one
side. If a cell remains behind, he advises placing the knob behind
it and then moving it on; he admits however that thus the danger
of injury arises. It is evident that micro-organisms with long fine
cilia are not improved by dragging along, and that one may safely
call this a harmful physical stimulus. On account of all these reasons
I use an eyelet in which I take up one cell, and place it at once
without dragging it, next to the culture drop. Only in very few
exceptional cases, as for instance when the cell for some reason or
another could not be easily taken up in the eyelet, one can have
recourse {0 this dragging (for which my eye-shaped needle can also
be used), but with my method at least the transport-drop will not
evaporate while on the way. I can as little welcome the modification
of bringing the cell at once into the culture-drop with the same
needle with which it was isolated.
NIEUWENHUIS says on p. 532: “it is clear that the parts to be trans-
ferred must be as far as possible from one another in the drop of
the material, in order to avoid a contamination of the needle; from
this it follows that the material must be very dilute”.
I willingly grant that when the cells occur far from one another
in the drop, one can be fairly sure that on taking the cell out of
the drop the needle will not be contaminated by the neighbouring
cells. When, however, in a mixture only comparatively few cells”
° ( 549 }
of a certain kind oceur, and one just requires that particular kind,
it ought not to be so much diluted, because the chance of getting
cells at the edge is much too small. And then there is certainly the
risk that in isolating one cell, one brings with it other cells which
cause the experiment to fail. Therefore I still find the use of two
needles necessary for difjicult cases (also, for instance, in dealing
with mucilaginous material). With the first needle the cell isolated
is brought near to the culture-drop, with the second, which is then
certainly still sterile, it is put into if.
In my original apparatus the needles are always placed on either
side of the microscope, on two separate stands; in iny simplified
arrangement with one needle stand, the first needle is in such cases
replaced by the second. For this naturally the cover slip used for
isolating must momentarily be placed on an ordinary moist chamber.
One can however, without the microscope, also stretch the culture-
drop with an ordinary platinum inoculation needle somewhat near
to the edge of the isolated droplet; then also the isolated cell will
come into it.
There are still a few short remarks.
Before Nisuwennuis lays the cover-slip, on which the isolation has
taken place, on the moist chamber for the further development of
the culture, he absorbs the drop of the material by means of a
filter paper. With his method this is necessary, for the drops must
for the purpose of being dragged lie close to another and this is
very likely to give rise to contamination of the culture-drop by
hyphae which grow out of the drop of the material.
Whilst it remains doubtful whether after this absorption no cells
are left behind, and germinate in the moist chamber, I here point
out that by my method the distance can be so great that there can
be no question of any such infection. I have never had any trouble
from it. There are advantages in leaving the drop of material in its
original place. The behaviour of the cells occurring in it (whether
the spores develop, whether the bacteria remain mobile) sometimes
enables important conclusions to be drawn.
Nisuwennvis lays no drop on the floor of the moist chamber,
because then the too considerable condensation on the cover slip is
troublesome.
This difficulty is avoided if the slips are cleaned in the way
described above, and if the moist chamber is not — as in his method
— placed on a fixed object in the incubator, so that the slide is
the warmest, but is, for instance, placed in a small box on 2 strips
of wood. Nisuwennuis thinks that the slight evaporation from a large
( 850
culture-drop can have no harmful consequences; after the above
mentioned investigations of Ciark and DuaGar caution is however
advisable.
Taking everything into consideration among the changes which
NikuWeNnvis proposes in my method, there is only one with which
(and then only partly) | am in agreement and which is also in-
corporated in my simplified apparatus (of which I had wished, for
certain reasons, to postpone the publication): the two needle holders
are replaced by one. When however he advises always the use of
not more than one needle in isolating, we differ entirely. If he bad
‘arried out more extensive investigations with difficult material, for
instance, with bacteria, instead of with the much larger fungus
spores, he would not have suggested any alteration.
I should be glad if the fact that the needles can now be obtained
commercially, should lead to a more extensive use of my method.
I am convinced that it has a large sphere of usefulness. Those who
from the detailed description in my last publication conclude that
the method is too difficult, are mistaken: I have thought it preferable
tv go into a minute description in order to make it as easy as
possible for those who use it, however tempting it was to give the
impression of a too great simplicity by a cursory description.
For the rest, those who hesitate to isolate bacteria, can work
with yeast or moulds.
The technique of the method will improve by extensive use, for
I cannot imagine it to be perfect.
With regard to the alterations, proposed by Nimuwenuuts, I felt
obliged to say at once, that in my opinion, they are not improvements.
Finally one hint more: I advise those who can afford it to
procure the apparatus with a moveable stand, on which the micro-
scope is placed; although it seems to be more complicated it is the
more convenient in use.
Mathematics. — “On the integrating of series term-by-term”. Com-
municated by Mr. J. C. Kiuyver.
(Communicated in the meeting of January 28, 1911).
When the function / (x) is developed in a series converging
uniformly for a
D D
fro da = lim > |u,(z) dz = = |u,(2z) dz.
i=b 0 Oe
a a a
Very often this theorem proves sufficient. Thus we find that for
O<«#<1 the equation holds:
Vs
(ww )
a oO. iL \S=!!
F(x) = = > (—1)p (i ) au",
and the development at the right-hand side is in this interval
uniformly convergent.
The series of the integrals
2 (1
r(s) > ——
(s) a Fgh
converges absolutely, if only s > 1 and under this condition there-
fore the equation
[es —!
] == 2)
e ((n =| > ys—! wo. (—1 jn
~~. dx = | —— dy = PF (s) = ——
é ‘ 1 ns
0
will hold.
However the theorem under discussion does not serve to show
that the above eqnation remains correct for 0 < s <1. Here as well
as in other cases this theorem needs amplifying and as such the
following theorem can sometimes serve.
When /’(z) is developed in a series of continuous functions we
shall be able to deduce
b
b
ie (a)\de = | Un (wv) dx,
0
a
out of
EE (2) = Uy (x)
0
as soon as is given:
1st. Su,(x) is convergent for a y.
I first suppose that the inequality holds for «< y. On the ground
of the third datum we find
ILA
Uy (a) Unt (a)
Ln = —— and Gr = acted
un(y) Un+1 (y)
to be positive numbers and the inequality expresses that @,41 < dn.
In the sequence
ans Op+ls Opt2s-++
the numbers are therefore not ascending and as according to the
2
first datum the series Sw,(y) converges, we conclude from the well-
0
known lemma of Aber, that
we wn
Sty (y) en = =2,(2)
P PB
is situated between G'v,, and Ke,, where G and A’ denote succes-
sively the upper limit and the lone one of the sums:
u(y), Up(y) + Utily), -++5 Mp (y) + Up+i(y) -- up +2(y) +.
If we take p large enough |G) and | remain below an arbitrary
small quantity *, so that we have for p large enough:
=
= = un | aS Ea) -
In the supposition under ee here concerning the fourth
i 4)
datum follows out of the convergence of Yw,(y) the uniform con-
0
D
vergence of the series w,(v) for all w, satisfying a¥y)
2)
the uniform convergence of uw (wv) in the range y< «<4, and
0
as this series converges for ea, we should have uniform con-
vergence in the whole interval of integration a w,(7)
0
converges uniformly, so that the equation
t u
wo
fr "(a)da == = | u,(a)dax
e
a
Oe
a
certainly holds, and when we then finally apply the principal property
of the uniformly convergent series we find when ¢ tends to 6
b t b
v n ies)
| F(a)dze = Lim J | u,(2)de == | uz(a)de.
a t=b 10 0
a a a
With this we have given the proof of the enunciated theorem and
it is clear that the proof holds if the third and fourth data only
hold for all numbers 7 surpassing a definite number.
For the evaluation of the integral
: dx
ey +1 l+a
(where s > 0) the theorem can be applied.
We have
Ge J a: ee
~___*___ —( toy - 0 = = (—1)" (to =) a,
1 + 1 a
and the series converges for O0<7<1, The terms do not change
| ge a aE ce
signs for O0< w <1, the quotient
| nti)
——| = 2
| U(x)
increases with w. The series of the integrals
@ (1)
KGS =
9 ns
converges for s >0O. The theorem therefore holds and we find for
all positive values of s
rys—l 2 —— r=!
aa dy D(s) = a —t
ey] laze
In general we shall often be able to use this theorem when eva-
luating an integral of the form
1
fro g (wv) de.
Suppose it possible to replace f(x) by a power series Y @, v" such that
0
io a)
the series = a, 2"g (x) diverges for «=1, but that the series of
0
the integrals
1
= .
SIG fe gq (a) de
Omere:
is still convergent. Then this series will certainly be equal to the
integral, if only g(v) does not change its sign in the domain of
integration, because then all conditions under which the theorem
holds are satisfied.
We shall likewise, if the development
. mane
0
0
if this last development converges.
56*
( 858 )
Physics. “Some remarks en the mechanical foundation of thermo-
dynamics.” *) Il. By Dr. L. 8. Ornstery. (Communicated by
Prof. H. A. Lorentz.
(Communicated in the meeting of Januari 28, 1911).
§ 4. In § 2 I have discussed some ensembles and I have shown
that they can be used to deduce the properties of a real system
because they are connected with the time ensemble and because the
majority of their systems is equivalent. I shall give in this paragraph
another deduction which for this purpose may show the importance
of the energy-space ensemble (and of the microcanonical one).
If in reality we want to obtain a system with a given energy
we take a°system of the same kind and supply energy to it or
abduce energy from it, giving at the same time the appropriate
values to the external coordinates. Let us suppose that it is possible
for us to eonstruet a system that contains exactly the required
energy. If we do not take special care to get a system of a definite
internal state, we shall obtain by or operations one of the systems
possible with the given energy, but it will be impossible to indicate
what kind of system will be produced. We can by no means
practically regulate the internal state arbitrarily, as it is impossible
for us to influence directly a single degree of freedom (e.g. the
phase of the molecules). But we can only give the values we desire
to the energy, density, or concentration in rather large parts, and
even this with a moderate precision. If in a great number of cases
we give the energy ¢ to a system we shall obtain it over and over
again in other states, and the same will be the ease if we bring
the energy of a great number of systems together to the value e.°)
The ensemble obtained in this way may be called a “real” energy
space-ensemble.
Instead of giving the energy ¢ to .V systems we can also select
them in nature. I shall term the ensemble thus obtained a nature
energy-space ensemble. The real and the nature energy-space ensemble
1) See These Proceedings page 817. Putting for the probability of the homo-
geneous system wy we find for that of a system specified by the numbers +,
w= W, €
6 is a function of the volume, the diameter of the molecules and the temperature.
2) The circumstance must be taken into account that the original system will
differ also in phase.
( 859 )
are not identical; the following considerations mutatis mutandis may,
however, be applied to both. I shall therefore in the following pages
only take into account the real energy-space ensemble. Constructing
several times a real energy space ensemble, we shall find that the
number of systems lying in a given element of the space /,—1,
can differ in those cases. How great this number will be, cannot
be said, if one does not know anything about the way in which
the energy is supplied to the systems. If, however, we proceed
without any scheme, the distribution of systems over the space
,,-, will differ very little in the majority of possible cases. The
distribution occurring in the majority of the possible cases must be
stationary. The most simple stationary ensemble is the energy space
ensemble discussed in § 2. ').
I shall now introduce the hypothesis that the real ensemble is
identical with an energy space ensemble.
If we had supposed the energy of the considered systems to have
a value between ¢ and ¢ + ds, we should have found another kind
of real ensembles which we can indicate by the term of real micro-
canonical ensembles. The most frequently occurring and stationary
ensemble is the ensemble with a homogeneous distribution. (Comp.
Gisps Chap. XI and XII). *)
The introduced hypothesis enables us to deduce the properties of
a real system with the help of the corresponding mean value in the
energy space or the microcanonical ensemble. An arbitrary system
can be obtained by choosing a system from a real ensemble; this
real ensemble is an energy-space or microcanonical ensemble; the
1) The ensembles having the constant A different for the strips are also sta-
tionary. Thess must be taken into account if we know something more concerning
the constants of integration.
2) The distribution of systems in a real ensemble can be chansed by the motion
of the representing points, if it is not identical with the energy space-ensemble.
It is impossible that in consequence of this motion an arbitrary real ensemble
changes to an energy space ensemble, if the distribution for the strips of § 3
deviates from that in the energy space ensemble. Suchlike ensembles are,
however, very rare among all the ensembles, built up of a given number of
systems in the space H2,—1. If the distribution over the strips agrees with that
in an energy space ensemble, but is different from this inside the strips themselves,
the ensemble will, by the motion of the systems, take states in which it deviates
very little from an energy space ensemble but periodically it will again differ
more from it. Also this kind of deviating ensembles is very rare. As for a real
microcanonical ensemble, which shows a distribution different from the homo-
geneous, the distribution will differ after a long time as little as we like from the
homogeneous in fixed elements of the space 2,1 which are not too small,
(Comp. Gress Chap. XII.)
860
properties of a real system are therefore those of a system chosen
arbitrarily from one of those ensembles.
If we know that the state of a system is stationary, the properties
of the system will agree with those of the most frequently oceurring
system of the ensemble; after a sufficiently long time every system
will come to this state just for the very reason one would say that
it can be thought to belong to a real ensemble. The idea of probability
of a real system, which strictly speaking has only sense in relation
to systems lying on the same path, can now be extended in the
following manner: the system is produced by a construction which
when repeated many times will lead to a real ensemble, the latter
is identified with an energy-space (or microcanonical) ensemble; the
probability that a real system is in a given state is therefore equal
to the probability of the same state in the energy space or micro-
canonical ensemble *).
§ 5. In the following I shall consider the canonical ensembles.
It is generally affirmed that these ensembles have no physical meaning
and that their introduction is only justified because of the simplifica-
tions, which they allow when used in the caleulations; also Hurrz
adheres to this opinion *). I think, however, that by changing a little
the considerations which enabled us to ascribe a physical meaning
to the microecanonical ensemble, i.e. by relating them to the real
ensembles, we can attribute mm the same sense a physical meaning to
the canonical ensembles. If we know that in natare by the action of
exactly determined canses a system of precisely the energy «, would
be formed, it is obvions to presume that in consequence of the small
1) By the following considerations we can avoid the mentioned hypothesis. Sup-
pose that a real ensemble has been constructed Xt times; in each construction we
take N times a point at haphazard in the space £1 and unite the chosen points
to an ensemble (or we proceed in the same way for the layer between - and
e+ ds). Kach possible real ensemble appears a certain number of times among
the % ensembles constructed. The probability W. of a given ensemble can be
defined, as this number divided by the total number of ensembles &. If aw. represents
MN
the probability of a given state in the eusemble under consideration then Zw, W>
1
can be taken as the definition of the probability of a phase, the sum has to be
extended oyer all the % ensembles. The hypotheses mentioned above means that
we put the probability for the energy-space ensemble equal to 1 and take for w
the probability im their ensemble.
2) This simplification is often not so very important; most questions which can
be solved by means of the canonical ensembles can be treated im a like manner
Without much complication, also by means of the micro-canonical ensembles.
( 861 )
and accidental deviations in the several causes not a system of exactly
the energy «, will be produced, but one of the energy «&; in general
(e, —) will be small in comparison to &,. Positive as well as negative
deviations will occur.
If we now construct a real system by trying to give the energy
&, to .V systems or by choosing N systems of this kind in nature,
we shall suppose that the probability that a system of the energy
&, +e’ will be chosen is as great as that for the one with the
energy «,—«’; a hypothesis which will be plausible as long as ¢’
is small. If the hypothesis is right, it may easily be shown that the
canonical ensemble will play a part in the definition of the proba-
bility of a system.
In analogy of other cases (e.g. the law of errors) it seems admis-
sible to suppose that in a real ensemble the number of systems
whose energy lays between ¢ and «+ de can be represented by
NAb=G€-pikds 4 3. . % 2 at (15)
It is not possible to prove this formula as long as we know nothing
about the way in which the energy is supplied to the systems, or
in which the energy «, of the systems chosen from nature is
determined *).
If we form hypotheses on this subject we can deduce (15), but
much importance should not be ascribed to such a deduction. *)
Proceeding further in the same way as in the case of the micro-
canonical ensembles we find for systems in the real ensemble whieh
are represented in each layer between ¢ and ¢ + de a homogeneous
distribution.
1) If we suppose that the ensemble is constructed by choosing the systems from
nature, the measurement of energy will be subjected to an error, the aualogy with
the law of errors therefore is slill more obvious. Only we have now the difficulty
that we do not know in what distribution the different systems of a certain energy
appear in nature.
2) To give an example take the following case. From a recipient of infinite
energy, the energy is supplied to N systems. Equal portions x are supplied to a
total amount of Nn portions to the systems of an inilial energy 0. The supply of
energy takes place in Ny distributions. In every distribution one system is taken
from the N systems, the energy « supplied to it, and the system replaced among
the others. This is Nn times repeated. It is evident that in a definite case not
each system has obtained the energy ”z
ep, but it is possible to indicate the
number of the systems containing an energy between m'z and (n'—1) z. If the
mentioned process is repeated several times, one distribution will be the most
probable or most (frequently occurring) among all the possible distributions and
this will be that for which (15) expresses the number of systems obtaining an
energy between ¢ and <+dée. If z is infinitely small, we can be sure that the
real ensemble obtained will be the ensemble characterised by (15).
( 862 )
If we represent the volume of the layer between /%,—; (€) and
Io, 1 (@ + de) by ef de, gle) being a determined finetion of € and
we imagine an ensemble in which the density in the mentioned
layer amounts to /(s), this ensemble will be identical with the real
ensemble if
Fie), Ge ete
7 (&,) On 0
From (16) results
log f (e) — log f (€,) + g(&) —g(é,) = — & (e —€,)°
developing for small values of (*—«,) we get
‘d ous) “dq (&) |
(e€—€,) ( de a de hee op
7 >=
d? li ( : a (é
7 4 (€ —€ )° . avy, =) aie Z = | vy —k(s ae Eadie
| ds” —y dé? z=—5)
7
d log f(&) mY dgp(e)
z- de — i dé E—en
a Bh dg (é) ae
: ds* si) dé? cr
A
Therefore
and
In first approximation
ofa = ko Sie ee
If we suppose that this formula is true for all values of ¢ and
d? log 7 (&)
dé?
that therefore can be put 0, we find for the number of
systems having the energy between & and «+ ce
(42) 4 ys (ee) 2
F(E) tt fo) maciees
dz, y
dq (€) 1 dz E—Ey
Putting =— and ‘(&,)e — Ne® w ‘or
uttin: ( de Ns @ am (8) Ne“ we find for
this number.
ae
Sp bel)
Ne dé op ae te ee ee (18)
so the ensemble is eanonical. The relation to be adopted between & and
——————
( 863 )
* (dad ple :
(= ) does not follow as far as I can see from the physical
dé
i)
signification of these quantities *).
pe ONG ee ;
Ginss has proved that the quantity ( a ie has properties corre-
=
sponding with those of temperature. The mentioned quantity, however,
has a definite value for a given value of the energy «,, so the
modulus of the canonical ensemble used has to be put equal to the
On . e
value of fe . The ensemble defined by (15) and the canonical
é
= —=)
ensemble (18) deviate slightly from each other, but these deviations
are of less significance the greater the number of degrees of freedom
is. The deviations are most important for those systems of which
the energy ¢ is such that (¢—s,) is large in comparison to ¢,, but
suchlike systems are very infrequent in both ensembles. We can
without fearing errors in our results suppose the real ensemble to
be a canonical one, and if we further suppose that in the real
ensemble the distribution in every layer is homogeneous, we find for
the probability of a system in the real ensemble
VSG
aS Wd CR o- 6 oa oo 3 6 (19)
The identity of the real and the canonical ensemble is no more
fully proved or to be proved completely than that of the micro-
canonical or energy-space ensemble. It exists in this respect that the
number of systems in the layer ¢...¢€-| de can be represented by
7 (ede, f(e) being a maximum for «= «,, as well for the real as for
the canonical ensembles; in the microcanonical ensembles without. it
7 (&)=9, to a certain degree the latter ensembles have therefore less
physical sense than the canonical, provided that we do not take as
startingpoint the single system and with it the time-ensemble, but take
into account that a given system has a not totally definite energy.
§ 6. Hertz has developed in the paper mentioned considerations
about the theorem that two systems of equal temperature produce
1) Gipps has proved (Chap IX (350)) that we have the relation
(|
ie ).ne Gah
In the real ensemble (15) the mean value (s—<,)? is equal to 2k, therefore in
the real and the canonical ensemble the mean value of the squares of deviations are
equal
( 864 )
after their union a system of the same temperature. He supposes
the connection performed in such a way that the two systems form
together a new system, of which the reciprocal energy is small in
comparison with «, + ¢,. The connection enables the systems to inter-
change energy. The (quantity 7 of Hertz is related to the average
kinetical energy in the ensemble and is interpreted by :
= nV en
Ep = ee — 9 T;
n being the number of degrees of freedom, V the volume of the
extension in phase where the energy of the represented systems is
JV
less than ¢, w is put instead of
Og
Hertz determines in a very elegant manner the conditions
necessary for two microcanonical ensembles of the energies ¢, and &,
and having 1,(e,) equal to t,(e,) to form after their connection an
ensemble of the energy ¢, +, and the temperature t,,(€, + &,)
so that
Tig (Ey + &5)) = Tai(E,) EE):
His considerations teach us only something about the equilibrium of
temperature for stationary systems if we have shown that the average
kinetical energy of a degree of freedom is equal to that in the
most frequently occurring system, while the conditions of Herrz
are complied with. We shall suppose this as proved and if we then
consider that two ensembles of energy ¢, and ¢, and of equal
t-value produce an ensemble of the same r-value, and that the mean
kinetical energy in the original ensembles is also equal and with it
the kinetical energy of the most frequently occurring systems, we
shall find that also the temperature of the stationary systems are
equal before and after the union.
Even if we unite systems in non-stationary state, we can deduce
something. If the temperature of the considered systems would be
equal after they had come to a stationary state, they would belong
to ensembles of equal rt. The system formed by their union belongs
to an ensemble with the same value of rt, the temperature therefore
adopted by the system formed if we unite two non-stationary sysiems
is, if this system has become stationary the same as that which would
have been adopted by the separate systems in their stationary state.
Also for the canonical ensemble we find the same results. Gipps
1) Conf. P. Herrz loc. cit. p. 243.
1) For gases and fluids I have proved this in my dissertation.
( 865 )
has proved that the modulus @ corresponds in all respects with the
temperature. The mean value of kinetical energy in an ensemble is
a
~@ and this average value is equal to the corresponding value for
9
most frequently occurring and ‘stationary system, @ can therefore
be used to define the temperature of a stationary system.
Groningen, Dee. 1910.
Physics. — “On vapour-pressures in binary systems with partial
miscibility of the liquids.” “Vax pur Waats-fonds” researches
N°. 2. By Prof. Pa. Kounstamm and Dr. J. Timmermans.
(Communicated by Prof. J. D. vAN per WaAats).
(Communicated in the meeting of January 28, 19J1).
In these Proceedings Vol. 9—11*) van per Waats derived a series
of conclusions concerning systems of not completely miscible liquids.
In this communication we shall compare three of these conclusions
with the experimental data which are to be found on this subject
in the literature, and with the results of some new determinations,
which follow here.
We shall discuss the three following points:
1. The shape of the p,7-projection of the three-phase curve L, LG.
2. The connection between the shape of the plaitpointline and the
existence of a maximum in the p,z-section of the surface of saturation.
3. The occurrence of points of inflection in the p,a-section of the
surface of saturation specially in the neighbourhood of a eritical
end-point.
§1. Van per Waats has tried to demonstrate that the p, 7-projection
of the three-phase line does not intersect the plaitpoint line in a
critical end-point, but touches it. From this very remarkable results
would follow.
a. In the ease of splitting-up of the plaitpoint line the three-phase
pressure would ascend regularly with rise of temperature. As. however,
te :
— has a very high value for
r
d
one of us?) remarked already before, -
c
i ee ee Se loa Nee dT
this line in the case of splitting up of the plaitpoint line ( never
dp
becomes higher than 0,04 degree per cumosphere and so the three-
1) See also Archives Néerl. (2) XIII p. 249—283 (1908).
*) J. Timmermans. Handelingen yan het 13e Vlaamsche Congres 1909 p. 120.
( 866.)
phase pressure would have to increase very rapidly in the neigh-
bourhood of the critical end-point.
’
4. In the ease of retreat of the plaitpoint line, ; would be
ap
negative in the critical end-point both for the plaitpoint line and for
the three-phase pressure; and as the three-phase pressure would
dp
certainly resume its usual course at lower temperatures (7, positive
(i
the three-phase pressure would necessarily present a maximum.
c. In the case of retreat of the three-phase pressure in the
pP
dT
neighbourhood of the critical end-point could vary between a very
a. dp .
small value (e.g. for butane +- aniline : p= 12.5 atm. per degree)
a
to infinite (e.g. for isobutane + metylalecohol); the plaitpoint tempera-
ture of this system does not appreciably vary between 10 and 70 atm.).
So the latter possibility would wrongly have been considered as
impossible by vaAN DER WaAALs’).
We have hardly any data as yet concerning the value of the three-
phase pressures, which would enable us to test these results. Only
a few observations of SCHREINEMAKERS *) about the system water —+-
phenol can be used for this purpose: they have been rendered in
table I.
(iA iB eee
; , |@; .
t p in mm o | pin mm o mercury
mercury per degree
°
29.8 29
2.26
38.2 48
| 3.33
42.4 62
4.05
0.3 94
5.16
16.5 126
6.66
60.1 150
7.44
64.4 182
10.45
Ae? | 951
| 432
1) These Proc. X p. 193.
*) These Proc. Ill p. 1. Ztschr. phys. Ch. 385 p. 459 (1900)
( 867 )
The critical end-point lies at 68° according to ScuREINEMAKERS; the
two vapour-pressures indicated for higher temperature refer to mixtures
of the critical concentration; they have been derived from VAN DER
beer caper, a
Len’), who has also determined the value of a for the plaitpoint
line. This is 197600 mm. of mercury per degree, and so it is of an
entirely different order of magnitude than the increase of the three-
phase pressure in the neighbourhood of the critical end-point (about
10 mm. of mercury). So these data are in flat contradiction to the
thesis mentioned, unless we should be ready to accept a very steep
ascent of the three-phase pressure in the immediate neighbourhood
of the critical end-point, where no measurements have been made,
but this supposition is difficult to reconcile with the rise of the two-
phase pressures of mixtures in the neighbourhood of the critical con-
centration, as appears from the last values of the table.
To have somewhat more material at our disposal, we have made
some more determinations. Though the conclusion, being of a purely
thermodynamic nature, must not depend on the nature of the system,
yet we have. fixed our choice on mixtures of normal substances.
With the measurements we have approached the critical end-point
as closely as possible. We have chosen one case of splitting up of
the plaitpoint line (cyclohexane -++ aniline) and one of retreat
(hexane and nitrobenzene), for which system the course of the plait-
point line had been accurately determined by one of us before *).
The substances used were very pure; we refer to the cited commu-
nication for further details.
The apparatus used is the same as had already been used by one
of us*) for determinations of vapour-tension by a static way. A
further discussion is not necessary. It was placed in a large thermo-
stat (80 L.); the pressures were read with a kathetometer with an
accuracy of 0.05 mm., after it had appeared by repeated measure-
ment that the equilibrium had set in. The measurements (which were
all made by Mr. TimMErMANs), were first made with rising tempera-
ture, then with falling temperature; the results always agreed to
1 mm., which may be considered sufficient for the end in view. All
the pressures were finally reduced to mm. of mercury at 0°. The
results obtained are found in tables Il and III; in the fourth column
of these tables we have given the vapour pressure of the most
1) Thesis for the doctorate Amsterdam 1598.
2) J. Tiwmermans. These Proc. XIII p. 507.
5) Pu. Konystamm. Thesis for the doctorate. Amsterdam 1901, p. 183, Comp
also vAN Datrsen. Thesis for the doctorate. Amsterdam 1906 p. 10.
868)
volatile component (hexane resp. cyclohexane) at the corresponding
temperature. These values have been obtained by graphical interpola-
tion from SypNey Youna’s results ‘). The fifth column at last gives
the difference between the vapour pressures of the pure substances
and of the three-phase system. This column clearly sets forth the
perfect parallelism of the two vapour pressure curves, which gives
a further support to the accuracy of the given measurements.
Here too the data for temperatures above the critical end-point
refer to the two-phase pressures of mixtures of the critical con-
centration.
TeA Boer
Cyclohexane +- aniline.
Temperature of the critical endpoint 319.09,
d
a for the plaitpoint line 166 atm. per degree.
p in mm. | 4 in tamt>, Soe
T ‘aT | D
of mercury of mercury hexane
23:22 | 90365 89.4 4-1 25
PomeeiUey 5
25.50 100.45 98.5 4295,
| 4 Sie
27.80 110.50 409.3 | 1.20
| 5.00
29.98 121.40 120.3 1.40
7.19
31.03 426.85 125.9 0.95
4.71
31.20 127.65 126.8 0.85
Repeated the next day:
31.195 PATIENTS) | 196.8 | +0.95
4.74 | |
31.100 | 427.20 | 196.3 | 4.00
| 4.46 | |
30.48 | 124.55 | 193.0 | 4.9
| 5.07
28.99 447.00 | | 445.4 | 4.80
| ‘71 |
27.29 108.00 | 406.6 2.30
| | 61] |
25.64 101.45 | 99.2 | 4.95
It appears most clearly from these measurements, first that the
dp
value of = for the three-phase pressure in the critical end-point is
ad,
of a perfectly different order of magnitude from that along the plait-
1) S. Youne and J. Fortry. Chem. Soc. London 77 p. 1126 (1900).
( 869 )
WINE IE, ANE
Hexane +- nitrobenzene.
Temperature of the critical endpoint 209.40,
d Sei
for the plaitpoint line = 53.75 atm. per degree.
I pinanita @e-vecdeah!. PLA I/D SoM ye
las In saa hexane D
ot mercury of mercury
al 7 |
18.65 AAG | 443.2 | -9.9
| Hie. «|
19.44 | 119.4 | } Self) OS}
| | 4.9 |
20.24 123.3 | 4121.4 1.9
hy 7
205625555)" 125.1 123.3 | 1.8
|
15.55 103.8 | 98.1 5.7
| 26
16.52 106.3 | 102.6 Deed
4.3 |
17.65 PED 108.2 3.0
4.0
18.65 115.8 AW32) 1] 2.6
4. | |
19.45 41957 LAVAS: | 2.55
|
18.22 115.0 111.05 3.95
BFA
19.05 119.2 115.2 4 ()
19.95 | 121.8 | | 19.3 2.5
| 5.1 |
20.30 ADA A | Hy IY eh I) | ies
point line, and further that both in the case of retreat and in that
of splitting-up of the plaitpoint line the three-phase pressure regularly
rises with the temperature to the critical end-point.
Preliminary measurements for the system isopentane + nitrobenzene
have shown that neither in this case of retreat the three-phase
pressure reaches a maximum, and then descends again ; in consequence
of an experimental accident we have failed to obtain accurate measu-
rements on this system.
If in this way the discussed thesis about the contact of the three-
phase-pressure line and the plaitpoint line appears to be incompatible
with experience, we also think that we can prove that the theoretical
basis of this thesis is wanting.
dp. Realte ;
The ai for the three-phase pressure namely, is given by the equation
dp _ (@,—#,) (n,—n,) — (@.—#,) (4 —m)
dT.., (@,—-«,) (v,—v,) — (#,— 2): (0,24)
(870 )
We shall think the vapour phase denoted by 1, the two liquid
phases by 2 and 38; now wv, and wv, become equal in the critical
end-point, but also 4, and j,, and v, and v,; so both the numerator
and the denominator become zero. It is in this that this case distinguishes
itself from the three-phase equilibrium solid-liquid-vapour, as VAN DER
Waatus observes, loc. cit.’) because when the concentration of solid
phase and liquid become equal, their volume and their entropy are
, in the following way.
-
: y { a dp
not equal. We arrive at a determination of
t
The critical end-point is a plaitpoint for which the phases 2 and 3
have coincided. Now we can represent the difference of the volume
and the entropy between coexisting phases in the neighbourhood of
a plaitpoint by :
Ov
Ov i
J Se SE ee +... and wo='y, v,—2,
Us Vs (v, 2 (= “a ° Ea oe We
So we may put for the limit:
Ov ) 1 ( ) Ov
1, == (t,— a, - and (7,—7,) = (a#,—«,) | —
Us Us ( Us 3 Oz, , Py (P} 1 ( u U ) a te
: 2 , _ dp
if we substitute these values in the equation of ==
a
oF
ha ee) || ——
dp 4 He is ; 17 @;) Oar, rT W.,
ee ee
eee Ov De (
7 as ,—#,) | 5
dee
On the other hand for the plaitpoint which arises by the coinci-
dence of w, and 2,, the following equation holds:
and if we
ae ur
(2 ) Wi. N2—Ns — (#,—#;) ae
1T ’ ,
CL Jpl. 28 Vos p25 Gee a |
Gs )pl
or if we apply again the same expansion into series as above, but
take the terms with (7,—2,)’? into consideration :
(2)
(5)
(%) _ \oet, Jer
1) Van DER WAALS. These Proc. X. p. 191.
( S71)
and there is no reason whatever why (2) and (1) should be equal.
Looking back it is now easy to understand how the opposed view
could assert itself. After having derived equation (1), vAN Der WAALS
‘ dp :
observes loc. cit. that this value is equal to (F) , Le. the rise of
@ &
the pressure when we make a section through the saturation plane
«=w,. And then he goes on a few lines further: “And the p,7-
projection of the plaitpoint line being the envelope of the p,7-projection
of the sections of the surface of saturation for constant values of.7,
the plaitpoint line and the p,7-projection of the sections touch and
so also the final point of the p,7-projection of the three-phase
pressure, as in that final point the last element of this pressure
coincides with the section mentioned” *). From two correct premises
an incorrect conclusion is drawn here. Equation (1) proves indeed
that the three-phase pressure must touch the p,7 projection for x,
constant, or in other words that the increase in pressure along the
three-phase line at the limit (critical end-point) is equal to the increase
in pressure of the two-phase equilibrium vapour-liquid, and this
result is in perfect harmony with the data of tables I, H, and II.
dp
dT
when we pass the temperature of the critical end-point. It is also
correct that every plaitpoint line in each of its points must touch
a section for z constant through the surface of saturation (surface of
two-phase equilibria), and this thesis is corroborated by equation (2).
But it has been overlooked in the conclusion from these two theses
There is no discontinuity whatever to be seen in the value of
that in the considered case the surface of saturation (surface of two-
phase equilibria) is not a two-sheet surface, as usual, but a four-
sheet one. Two of these sheets pass through the eritical end-point ;
so instead of a mutual contact of three lines, as VAN DER WAALS
assumed, we get a contact of four lines in pazrs; the three-phase
line touches the liquid sheet of the coexistence liquid-vapour, and the
plaitpoint line touches one of the liquid sheets of the coexistence liquid
liquid. The experimental corroboration of this last thesis is already
included in the observations communicated previously by one of us’).
For it appears convincingly from them, what moveover is a priori
io be expected, that the concentration of the plaitpoint changes only
exceedingly little with the temperature, and that certainly in the
beginning the increase of pressure required to keep a mixture of
1) Loe. cit. p. 192,
2) These Proc. XIII p. 507.
Or
~]
Proceedings Royal Acad. Amsterdam. Vol. XIII
the concentration of the eritieal end-point in homogeneous state at
different temperatures, may be substituted for the rise of the plait-
point pressure proper with the temperature. And this is nothing but
the thesis mentioned.
§ 2. A second thesis derived by van per Waats, which can be
tested experimentally, states, that in the case of splitting up of the
plaitpoint line always a minimum critical temperature of the unsplit
mixture must be present, so in general also a point where the con-
centrations of vapour and liquid become equal (maximum vapour-
pressure in the p,v-line; minimum boiling-point in the 7\-lme). In
the ease of retreat such a point is possible, but not necessary.
‘In the two cases mentioned in the preceding §, the measurements
seem to prove the existence of such points, because the three-phase
pressure has been found higher than the value of the vapour-tension
TAY Ba EV.
Hexane + aniline.
Temperature of the critical end-point 68°.9,
Concentration
weight of | Boiling: g@7 dT
> the aniline : = - per %/o
tol00parts point | ¢ dx
of mixture |
| |
0 | 0 68.95
0.170 18.04
0.0388 4A8 69.65
0.4175 19.41
0.0859 9.34 70.55
0.19 90.93
0.1205 12295 elie
O14 14.33
0.1833 19.52 TENG)
0.08 8.32
0.2795 | 29.55 | 72.95
0.0383 3.43
0.3524 | 37.04 73.20 |
0.013 1.29
0.4296 44.88 73.30
0.013 1-27
0.5083 52.77 73.40
0.007 0.72
0.5778 59.67 73.45.)
0.024 9.40
0 6403 | 65.80 73.60 |
0.064 6.28
0. 6880 70.45 73.90
0.36 35.20
0.7505 76.48 76.10
| 0.74 70.83
0.8458 85.57 82.85
7.04 658.6
ee | 100 184.40 | |
( 873 )
lA BLES:
Cyclohexane 4 aniline.
Temperature of the critical end-point 319.0.
Concentration
weight of, Boiling- | g7 eae
the aniline | — per %/p |
* ~~ to100parts. point § @¢ F dx
| of mixture |
0) 0 80.75
0.243 96.95
0.0167 4.85 81.20
0.206 2967
0.0586 | 6.45 82.45
0.185 90.412
0.1083 14.85 tetany lta)
OP i353
0.2048 | 22.99 84.55
0.090 9.51
0.2749 } 99 .55 | 85 15
| 0.406 11.04
0.3519 37.53 86.00 |
0.416 11.84
0.4937 44.86 86.85
0.419 14.98
0.4988 52.41 87.75
| 0.445 | 44.45
@.5576 | 58.95. | 88.60 |
| 0.204 20.08
0.6074 | 63.43 89.60
0.70 67.24
0.6892 71.05 95.10
3.8 987.3
1. 100 184.40
of the most volatile component is according to Youn. But a more
accurate investigation shows that this difference falls entirely within
the limit of errors of the measurements. For first of all the
differences between the values given by YounG and those given here
are always very small (2 a 3 mm.), and they can be caused by
traces of dissolved air, which, as is known, is exceedingly difficult
to remove’). Then the hexane we used, was slightly less pure than
that of Youne (too great density viz. 0.67713 instead of 0.67693 0°/4°),
whereas on the other hand our cyclohexane was purer than that of
Youne (higher melting-point 6°.50 instead of 4°.7), and these impurities
are sufficient to explain the deviations.
For a further confirmation we have investigated the boiling-point
line of these systems*). The experiments were made with BeckMANN’s
apparatus and with a thermometer of Baupry, graduated in fifths of
degrees, and provided with a correction table; all the results have
been reduced to the normal pressure of 760mm. For both mixtures
1) Cf. Pu. Konnsramm Dissertation p. 179.
2) Boiling point line of isopentane +- nitrobenzene see Addendum p. 957.
57*
( 874 )
the mixtures rich in aniline were very viscous, and showed great
super-heating, which sometimes ascended as high as 25° degrees,
and rendered any measurement impossible. The results have been
colleeted in tables TV and V.
Further consideration and comparison of these data shows that we
have to do here with systems interesting for more than one reason.
In general the rule holds that of two substances that with the larger
molecule has also the greater @, and accordingly is the less volatile
one. In accordance with this most of the examined systems belong
to the righthand or to the middle region of the general diagram of
isobars. Now the mixtures of aniline with hexane and cyclohexane
present systems with a very pronounced difference in volatility.
Whereas hexane and cyclohexane have a vapour tension of 125 mm.
a 150 mm at + 38°, that of aniline is less than 0,1 mm. at that
temperature‘). Notwithstanding this aniline has the smallest
6 (0.006123 in the ordinary units *), 0.006247 for cyclohexane and
0.007849 for hexane). That in spite of this the aniline is so much
less volatile is owing to this that here the @ does not rise, as it
usually does, and even rapidly, with increase of }, but even decreases.
The a for aniline is in the same units 0.05283 to 0.05190 for eyclo-
hexane and 0.04928 for normal hexane. So we have either systems
with continually decreasing temperature of the unsplit mixture (lefthand
region) or systems with a minimum 7% (middle region); in which
case we are, will depend on the value of a,,. Now theory teaches
that the existence of a point where v, = 2, (maximum in the pst=
curve, minimum in the 7’,v-curve) is in the closest connection with
the presence of a minimum critical temperature of the unsplit mixture.
These two properties occur namely at the lowest temperatures for
the same value of w; at higher temperature the mixture where
x, =, shifts always further to the lefthand side (smaller 6, so here
to the aniline-side)*). Now as the point 7,—., is not present in
the boiling-point line, so at higher temperature, we must conclude
for the present that really the differences in column 5 of table II
must be aseribed to difference of purity between the substances
investigated by us and by Sypney Youne. If a further investigation
should prove the contrary, so that at lower temperature a maximum
does exist, then we should meet here for the first time as far as
we know with a case that is in opposition to the rule given by
1) Kautpaum. Z. phys. Ch. 26 p. 603 (1898).
2) See Lanpo.tr and Boérnsretn’s tables.
3) Théorie moléculaire § 9. Cf. further van per Waats, These Proce. IV. 549
and Kounstamm Z, phys. Ch. 75, p. 527 (1910).
{ 875 )
vaN per Waats about the displacement of the point, =.v,. Perhaps
the best way to decide this question will be by a direct determination
of the plaitpoint line L—G. We hope to carry it out as soon as
we shall again have a sufficient quantity of cyclohexane at our disposal.
There is another circumstance which draws the attention in these
systems, and which also points in the direction of a non-existence
of a point «,—a,. We refer here to the very great difference in
volatility between aniline and the respective other components, of
which we already spoke. At the temperatures of examination the
vapour tension of hexane and cyclohexane is more than 1900 times
that of aniline. Now it does not seem probable that the vapour tension
of a substance could rise by the addition of a substance so much
less volatile, as would be required for a maximum. In general this
is even considered as so self-evident that when the two components
differ very much in volatility, the validity of van ’r Horr’s law is
dp
generally simply accepted =o 1; so im— = 0. And this is
pax wv
1
nearly always in accordance with experience. That, however, a great
difference in volatility does not always justify the supposition
av, “ye . .
lin — = 0, the systems aniline with hexane and cyclohexane, and in
av
1
a still higher degree nitrobenzene with isopentane and hexane prove,
because in the latter the difference of volatility is still greater. For
what conclusion we may want to draw from tables II and III
concerning the existence of the maximum, this is conclusively proved
by it, that the vapour pressure line descends very little from the
edge if at all. Take e.g. the measurements of the two-phase pressure
for a mixture of the critical concentration just above the temperature
of the critical end-point. These mixtures have a concentration of
about «= 0.5, but their vapour-pressure is not measurable lower
than that of the volatile component in pure state. And compare
with this eg. the mixtures of aniline and nitrobenzene with ether
examined by Raourr'). Though at a concentration of 50 °/, the vapour
pressure has not diminished to half its value, as extrapolation of the
rule of van “t Horr would give for these non-diluted solutions, yet
the ratio found (about 3/5), differs only comparatively little from. it.
It is true that a similar phenomenon as for the systems mentioned
was already known for phenol and water, but the abnormality of
the two components led us to suppose that this was caused by this abnor-
mality. The three systems examined here show that also for mixtures
1) Z. phys. Ch. 2 p. 353 (1888).
( 876 )
of normal components which differ greatly in volatility highly im-
portant deviations from the rule of vay ’?7 Horr’) may occur. For this
a
it is required but also. sufficient, that the value of /=———
V aya,
descends only comparatively little below unity (in these cases e.g.
to about 0.85). This lower value of @,,, however, is always accom-
panied by a region of non-miscibility. In connection with conside-
rations on systems of an entirely different nature one of us will
shorily return to this question,? and {discuss if} more {fully ; we
shall therefore not dwell any longer on this point. We shall only
draw one more conelusion from what has been said. If already
U
an unusually small value of / is required to prevent lim —
vy
from becoming equal to zero for mixtures of a very diverging degree of
volatility, this value will of course have to be taken still smaller, if im =
ve
is put larger than 1, and so if it is assumed that the concentration
of the so much less volatile component is yet greater in the vapour
than in the liquid, as the existence of a maximum would require.
Henee we see a corroboration in what has just been said, of the
indication obtained from the boilingpoint lines that at lower tempe-
rature a point v,—=.r, does not occur in the figure either. For
the same reason it seems less probable that the system sulphuric
acid -- decane will possess a maximum vapour pressure, though
it belongs to the type of the splitting up of the plaitpoint line. *)
From this it would follow that van pur Waats’s rule which states
that the splitting up of the plaitpoint line always involves the oeeur-
rence of a minimum 7% is too narrow, because a point of splitting
up of this line can also occur in systems from the lefthand region of
the diagram of isobars, provided they do not move too far away from
the region where liquid and vapour concentration become equal.
Yet an examination of all the known data shows that by far in
the majority of the cases splitting up of the longitudinal plait will
only oceur for systems with a minimum 7. We have collected all
the experimental data in Table VI- Those concerning the plaitpoint
') Of course we do not mean here deviations for concentrated solutions, for they
occur in every system. But we mean that van “r Horr’s rule need not hold as
limiting law for extreme dilution either for all mixtures which differ greatly in
volatility. Moreover the condition must be fulfilled that the two substances readily
mix in the liquid state, in other words that we are very far from a region of
non-miscibilily.
2) Timmermans and Kounsramm, These Proce. Sept. 1909, N°. 15 of the table.
(2877)
ed Bye vi
is
System | Type
=== ==T= ————— | —
Amylene + aniline X R| No maximum
oP, F '{D. Konowatow. Drudes
+ — 4 nitrobenzene Aa RE » Ann. 10 p. 360 (1902),
Pentane ++ a Do UR ” |/
‘ |
Hexane + : X R ye |
7 + aniline X R sik) en |) This communication.
Cyclohexane -+ aniline >») oe at? |
Ethane + methylalcvhol Ge VIE °F |
» + ethyl 5 Dual " Is P. KUENEN and W. G.
VW Rosson. Phil. Mag. (5)
» + propyl ,, GAL 5 | 48 p. 180 (1899).
5, de tastigl) ne It . |
: et e |{ BUcHNER. Thesis. f. the
Carbonic acid ++ o-nitrophenol X L | rs octorate Amst. (1905).
sant water | CHUKAREW. Z. phys. Ch.
Nicotine + water If | 5 71 p. 100 (1910).
: i ¥ VAN Rosse. Z. phys. Ch.
SHEE LN GTEMS AE as L? | (Minimum) | 62 p. 681 (1908).
Sulphur + toluol R? No maximum
» + xylol
Ether + water
Water + phenol
» + aniline
» + isobutylalcohol
»» + iscamylalcohol
» + butyric acid
» + isobutyric acid
» + isovaleric acid
» -t sec. butylalcohol
» + methylethylketone
» + acetylacetone
» + triethylamine
Propane + methylalcohol
Isopentane +- 3
Hexane -+- 7
Cyclohexane -++-
”
Carbon disulphide-+-methylal cohol
”
+ acetone
Benzene ++ formic acid |
\ J.K.Haywoop. J. of phys.
Ch. 1. p. 232 (1897).
R? 7
J. P. KuENEN and W,C.
L? Maximum Rosson. Z. phys. Ch.
; | 28. p. 349 (1899).
S 24 |. A. H. SCHREINEMAKERS.
S 5 | Z-phys. Ch. 35.p.459(1900)
R »
eer
R D. KonowaLow. Wied.
Ann. 14. p. 3% (1881).
R ”
R ”
R »
J. TIMMERMANS.
R 7
R ( SCHUKAREW. Z. phys. Ch.
” ( 71 p. 100 (1910).
IL; y)
R » i P. KUENEN. Phil. Mag.
S (6) 6 p. 637 (1903).
S 3 |
S os Lecart. Diss. Brussel 1908.
S
G. RyLanp. Amer. Ch. J.
22, p. 384 (1899).
S?| Fi |
W. Nernst. Z. phys. Ch.
” 8. p. 110 (1891).
( 878 )
line have been derived from our preceding communication ; those
concerning the vapour-pressure-lines are spread in the literature ; we
have referred to the original in every case. The cases of splitting
up are marked by an S, those of retreat by an /, lower eritical end-
points by an ZL. The sign NX indicates that the concentration of the
vapour phase falls outside that of the liquid phases. A note of inter-
rogation marks doubtful cases. We have also inserted the only case
known of a minimum vapour pressure being attended by unmixing;
as is known it is almost certain that for these systems there exist
compounds between the components.
§3. The last point we want to discuss is the occurrence of points
of inflection in the p,r-line specially in the neighbourhood of a
critical endpoint. As has been set forth at length by Kunpn*), in
the critical end-point these lines possess a point of inflection with
horizontal tangent. So above the critical end-point (we suppose it to
be an upper mixing-point) there will continue to exist a point of
inflection in the neighbourhood of the critical concentration, but the
tangent is no longer horizontal in this point of inflection. This shape
of the p,a-line is in close connection with a similar shape of the
boiling-point or the melting-point lines in the neighbourhood of a
critical end-point. With regard to the shape of the melting-point
lines we possess important systematic investigations by FLASCHNER
and RANKIN *).
Concerning the boiling-point and the vapour tension lines of this
TABLE VII.
Temp. of the crit. end-point.
System 1 els is Observer
te oe 2 D. KonowaLow. Drudes Ann. 10
Amylene + aniline 1.5 18 4 IP 360 (1902).
x : * : : ) ) §D. Konowatow. J. de Ch. ph.
Isopentane+dichloroacetic acid |
(2)? 4+? Pr?
from which n and x have to be solved. This problem becomes much
simpler, and yet scarcely less general, if we confine our attention
to the surroundings of each of the characteristic frequencies r, separately.
In equation (2) we therefore put apart the term relating to the
selected r,, and designate the other terms of the sum by a variable
index /i:
Oh Q
es | a mT ae TEED Seo ROA aay
yin e—rv? vp,’ +in'p—r?
Because we only consider such values of ry as differ little from
r,, we are allowed to replace »v by r, in the terms of the sum-
0
mation =, and then to neglect 7y,r, relatively to v,° —>»,* (the
damping connected with », being imperceptible near y,). Writing
»
r, =, and therefore (u being small) »*° — y,* = 2r, wu, we may
‘
put, instead of (4):
P =) Oh 0
SS re
Di —D, YP (2u—ty )
or
oO
oS ho aaa) thera. fie) fy iG (0)
where 7, represents the value which, in the small spectral region
we are considering, the index of refraction would show if there
were no electrons having the proper frequency »,.
One might proceed to the separation of the real from the imaginary
part of this simplified equation, and then solve » and %; but as the
result would not yet be very simple, we shall first consider the
special case that the modulus of the complex second term is small
( 884 j
compared with 1°, for all values of ge lying within the region we
are concerned with. Then ww? — 7,*
» may be replaced by 27, (n —,),
and separating the real from the imaginary part, we find:
: OU
” py
Nv (40? +2”)
or :
Ne Pema ec. (((0))
2n,v, (47 +»)
eae Leas O)Mine bs |
=n, —
(5)
which formulae easily show the symmetry of the curves representing
nm and nx as funetions of mu.
As to ”, it is clear indeed that n= 7, for «=O, and that for
some positive value of w (i.e. on the violet side of »,) 2 is smaller
than 2, by a certam amount, while for an equal negative value of
gw (on the ved side) 7 is larger than 7, by the same amount. For
1
u=—'/,r, m reaches a maximum:
1) °
=n, + ——,
4 n,p,v'
and for u1=+?/, ya minimum:
0
LL =p. = = ae
4n,v,v
fe ‘ es Lk 5 Y
The attenuation coefficient nx has its greatest value ——— at
27,v,0
=e Olea
oO
the point w= 0; passes the value —— , Which is half that of the
!
Vt oo?
maximum, at «= + 7/, v', i.e. exactly there where the maximum
( 885 )
and the minimum of 7 ave found; and, with increasing 1, approaches
zero on both sides. Fig. 1 (taken from Voier Le. p. 115) shows the
curves representing the two functions. We may consider Yr as
measuring the width of the dark line appearing in the spectrum,
Indeed, the slope of the intensity curve is much steeper than the
slope of nz, because the strength of the transmitted light (provided
we are not dealing with the radiation through a thick atmosphere,
4x
NA. Z
4
ef. §5) is given by /=J,e 2 being the length of the path
through the gas. The dotted curve represents the reciprocal value of
the intensity of the transmitted light on the supposition that for
Ww— Owe havemi——-/, 55
half its maximum value, we find /='/ , /
» so that at w= + 1/,»', where mx has
,- Almost the whole of
the dark line thus lies between » = —’/,»’ and « = + 7/, v'?).
§ 3. Cases in which the anomaly of the dispersion curve is greater.
Our object being to apply the results of the theory to the inter-
pretation of the solar spectrum, we must allow for the possibility
(@)
~
that perhaps not in all cases the modulus of may be
y(2 u—ir')
taken to be small as compared with m,’ (e.g. when we are concerned
with very strong lines, like the calcium lines Hand 4’); we therefore
return to equation (5). Separating the real from the imaginary part,
we obtain
ee) 1/ )!
Zou /,@2
2 Z 2 se 2 2N
SV SH) — = = Handa 4 — ———<——
‘(4 a? +”) v, (4 w? + v')
The substitution of the second equation into the first one leads to
; »_ — 29u-+"/, 9v'% = oH + */, ov'x
n —n, = - eae or n—-n, = —— eG)
Vo(Ahe sm) a(%-+ 2,),(4°-+- 9")
from which we deduce
ee
ov'x ou
i ans — eeCie = (Cs)
/,(n + n,) v, (4? + v'”) /,(n + n,) v, (du? + y’)
A similar position as, according to (6), the curve n takes with
respect to the straight line 7,, it assumes according to (8) with
respect to the curve n, + d (if d represents the second term, which
is variable with m and z). By that term d the character of the curve
nm is, however, scarcely influenced, because ‘/, »'% is small in com-
1) We shall see later on that in the light which has traversed the solar
atmosphere, the apparent width of the real absorplion lines must be even less,
because part of the attenuation depends on scattering, and this part follows a
law different from the exponential one.
( 886.)
parison with go Even within the region of strong absorption, the
term J is of little consequence. Let us for instance consider the
frequency where 4=='/,r. There the ratio of the second to the
third term is
1 ' 1 ! 1/
U/C at Ne —— Daaehes p
4 2 /2
3.
There ave no experimental data at my disposal from which the
values of % might be deduced for calcium vapour; but for sodinm
vapour the maximum value of mz was found to be LO~°*), whieh,
at the indicated spot of the spectrum, makes nz = 5 X 10~4, and,
consequently, 1/,% = "/n X 2,5 x 10-4. For greater values of =u
the said ratio decreases rapidly. So the seeond term of the second
member of (8) may be neglected.
But in the denominator of the third term we meet with the
variable factor '/, (2 —+-7,), where in (6) the constant factor 2, occurs.
It follows from this circumstance that now the dispersion curve does
not show the perfect symmetry of the one which represents equation
(6). The character of the deviation becomes apparent from equation
(7) if, omitting the term */, ov'x, we write:
- 2ou
i = ny = eave
», (4u* - v)
With respect to the point of intersection
P of the horizontal line n,? (fig. 2) with
the vertical line « =O the curve represent-
ing 72° is symmetrical. Let us now suppose
n,—=1, then the line 7, coincides with the
line n,*. Constructing, in the same figure,
the curve whose ordinates are the square
roots out of the ordinates of the first curve,
we immediately see, that the “anomaly” of
the index of refraction 7 is greater on the
violet than on the red side of the line. It
is questionable whether absorbing vapours
Fig, 2. will present cases in which this difference is
ereat enough to show itself in the observations.
§ 4. On the nature of the damping parameter. — A permanently
acting cause why the vibrations of an electron die out, is the faet
that it radiates waves in all directions, thus ‘scattering’ its kinetic
energy. An electron, moving with the variable velocity v, experiences
a force due to its own field, opposite to its acceleration, and, in
1) W. Vora, |. c. p. 142.
dv . ; ,
first approximation, proportional to —; this accounts for the inertia.
at
. dv ; ;
But the force also contains a term, proportional to ~~, viz: °)
(
2e dv
a
ONCE he
If now the motion is periodical: v = 6 cos pt, we shall have
dy ms
— =— pr, so that we may put
dt?
2 pe? div
=i — , -
3) Cc? dt
where w means the elongation at the time ¢.
This term of the force may therefore be considered to express a
“resistance”, being proportional to the velocity and having the
opposite direction. The numerical value of the coefficient is small;
and that the resulting attenuation of the vibrations really is insigni-
ficant, appears from the known phenomena of interference with
great differences of path, which show that after some LOQOOO vibra-
tions the amplitude of an electron has scarcely diminished. On the
basis of this cause of damping we are not able to account for the
absorption of the incident light, ic. for a transformation of the
radiant energy into heat or other forms of energy. The scattered
light remains radiant energy of the vibration periods occurring in
the original beam of light.
In order to explain absorption, Lorpntz assumes, that the vibrations
of an electron excited by incident waves of light, go on undisturbed
only during a certain interval of time 7, and that then, for instance
in consequence of the collisions of the molecules, their energy 1s
transformed and distributed among other systems. *) ‘This idea may
be expressed mathematically by giving the damping parameter / the
2m
value . It is not necessary, however, to identify 7 with the mean
T
length of time elapsing between two successive collisions of a mole-
cule; indeed, after a much shorter interval 7 the amplitude of a
resonant (or almost resonant) electron might already have increased
to such a value, that also the other components of the molecule to
which it belongs have been thoroughly shaken, and have assumed
1) Lorentz, The theory of electrons, p. 49; Encyklopiidie der math. Wiss. V.2,
188; ABRAHAM, Theorie der Electrizitit Il, S. 72, 123. In the above formula e
is expressed in the C, G. S. unit reposing on CouLomp’s law.
*) Lorentz, The theory of electrons, p. 141.
55
Proceedings Royal Acad. Amsterdam. Vol. XIII.
(888 )
part of ifs energy. In that case we are already witnessing an “ab-
sorption” process; the further transformation of the energy into
heat, ete. ensues by collisions.
According to this conception, absorption of radiant energy only
takes place, when by resonance certain electrons are set vibrating to
such a degree, that energy is imparted by them in an irreversible
way to other parts of the systems to which they belong. As to the
particular conditions of this process, we can only guess at them.
Lorentz has shown?) that the damping influence of collisions may
approximately be expressed by introducing into the equations of
motion a term, proportional to the velocity of the electron. But if
the absorption process already begins within the molecule, before a
new encounter takes place (as Lorentz thinks probable, 1. e. p. 142),
it is quite conceivable that the amplitude, and, therefore, the velocity
of the resonant electron must have inereased beyond a certain limit,
before a continual transfer of energy to other parts of the same
molecule can result®). If the connections really are of that kind, then
waves which on account of imperfect resonance impart only sma//
mean velocities to the electron, will suffer mo absorption at all: the
part of the damping parameter that is due to absorption, will sink
to zero at a certain smal distance on both sides of the centre of the
absorption line. This, of course, is an hypothesis to which, in the
absence of a deeper knowledge of the internal structure of the mole-
enles, we are unable to give a solid foundation, but which may be
put to the test by scrutinizing the deductions following from it.
Suppose a beam of white light to pass through a rarefied gas
having rather sharply defined periods of free vibrations *), then,
according to § 1, the spectral region in which effectual co-vibrating
occurs, is only little wider — for each kind of electrons — than
1) Lorentz, |, c. Note 57.
») This conception agrees very well with a new radiation hypothesis, recently
proposed by Piaxck (Verhandl d. Deutschen physikalischen Gesellschaft 13, p. 138 ,
according to which accwmulating radiant energy by resonance is a continuous
process, whereas emitting radiant energy only takes place by definite “light-
quanta”. — Now, let the forced vibrations of an imperfectly resonant electron
allain an intensity sufficient for it lo emit light-quanta by itself, but not sufficient
to shake the other electrons, belonging to the same molecule (and having frequen-
cies of their own), to such a degree as would be necessary for them also to
emit quanta: then part of the incident radiation is scattered by the electron first
alfected, but there is no absorption, no transformation of the accumulated energy
into energy of some other kind.
8) The proper periods are never defined with perfect sharpness, owing to the
disturbing influence of collisions and to the Doppter-effect.
)
.
t
( 889 )
the region of their proper periods; but, strictly speaking, co-vibrating
takes place in some degree throughout the spectrum, though with
decreasing intensity as one recedes from the line corresponding to
the free vibration. Now, according to our hypothesis, the same cannot
be said with regard to absorption, this process being contined to a
narrow part of the region of resonance.
Let us consider the share which scaétermy has in the act of damping.
Within the region of strongest absorption it keeps in the back-ground ;
2° ¢* —20)
indeed, for sodium light the factor ——- amounts to only 2 >< 10 ~,
. Be
while the value of the entire damping parameter in sodium vapour
was found to be: h=mr'=7 » RES 11.2 10°=7.8 10%)
But on the other hand, we have no ground to doubt, as in the case
of absorption, the proportionality of this damping effect to the velocity,
however small it may be*). Seattering extends all over the spectrum,
wherever the proper frequencies of the electrons may be found.
Indeed, apart from the theory of absorption and dispersion RayLeicH
has proved that a beam of light of intensity ./, and wave-length 2,
after having travelled a distance « through a mass of gas whose
index of refraction is 2, and which contains V seattering molecules
per unit volume, will have sunk to the intensity
32 73 (n—1)?
— — = a.
St xe Bi. N
32a3(n—1)?
rate inde (2)
The quantity s= is called the coefficient of scattering.
34'.N
_—' n—1 :
Let A be the density of the gas, then he Rk may be considered
constant for any given wave-length. As we may put 4 proportional
= Re ' n—l hee 2
to NV, say A =/.N, the expression =f. Rf is also a constant
for any definite kind of light. Introducing it into the coefficient of
scattering, we find
oon Ne he oon me? LNG fhe
ee = = ca bee Beene)
on} on
where & represents the refraction constant of the medium.
The coefficient of scattering is thus inversely proportional to the
') From observations by HaLLo, concerning the magnetic rotation of the plane
of polarisation in sodium vapour, Vorer calculated: v'= 11,2 > 101. Cf. Voter,
Wiensps L493:
*) J£ we admit Pranex’s new radiation hypothesis, this statement will have to
be corrected.
58*
( 890 )
fourth power of the wave-length, direct proportional to the density,
to the average mass contained in the medium per scattering particle
and to the square of the refraction constant. As the latter varies
strongly in the neighbourhood of a proper frequency, also if the
damping parameter is small or even approaches zero (Cf. Vorer, Le.
p. 118), the coefficient of scattering will assume widely different, and
relatively great values in such a region; it only vanishes for waves
travelling in the medium with the same velocity as in the ether, i.e.
in places of the spectrum where Rk =O, or n= 1.
The effect of absorption and scattering may be considered from
two points of view. First we may inquire into the influence of these
two damping causes on the motion of the electrons, and, consequently,
ou the optical properties of the medium (as characterized by 7 and z).
The second point of view is that in which, the incident light being
given, we desire to study the intensity and the composition of the
light that leaves the absorbing medium.
So far we have only considered the first question. We concluded that
for waves, belonging to the nearest vicinity of those corresponding
to the free vibrations of a gas, the damping parameter 4 must be
the sum of two terms:
jp ee. . e
that in the middle part of that narrow region the first term is great
compared with the second one; that very probably, however, the
value of the first term sinks rapidly to zero at a short distance from
each of the proper frequencies, so that in the rest of the spectrum
it is only the effect of the second term which remains.
The parameter /, therefore, is not a constant, even if we confine
our attention to a part of the spectrum so small, that the variation
of the factor »? may be neglected. Nevertheless, our fig. 1 (p. 884)
gives the principal features of the index of refraction as a function
of the frequency, with a fair degree of exactness, because the
character of the dispersion curve is much the same for different
values of /. The relation, for instance, that the maximum and the
minimum of 2 are found where w= = 7/, »', will continue to hold, if
at these points of the spectrum the second (constant) term of /
already prevails. But if at the points where ft passes the values + 1/, 9,
the funetion pv (or /) increases rapidly with decreasing absolute
value of uw, then the distance between the maximum and the minimum
of n must be greater than 1.
§ 5. Radiation through an extensive atmosphere. — We shall now
( 891 )
proceed to a discussion of the second question, that which regards
the composition and properties of the light that has traversed a
very thick layer of gas, the atmosphere of a celestial body, if we
suppose the emission curve of the original source of light to be
continuous. -
Evidently the solution cannot be found by simply putting the
value
into the formulae (8) or (6a), and then, for each wave-length separately,
substituting the resulting value of xx into an equation of the form
4x
—— nr. 2
Ree Be oo a eee
(in which z represents the distance travelled by the beam through
the layer of gas).
For this would lead to an entirely erroneous result, even if
the layer of gas were perfectly homogeneous. It is true that the
part of the attenuation, which is due to absorption, conforms to the
law expressed by (12), proceeding in a geometrical progression when
the path through the gas increases in an arithmetical progression ;
but the same does not apply to the part that is caused by scattering.
If the source of light and the layer of gas are very extensive, we
must take into consideration that each electron emits a certain
quantity of seattered light owing to irradiation from all directions,
and partly joining the directly transmitted beam. The attenuation of
the beam must therefore proceed less quickly than it would do
according to the law expressed by (12), which holds for the loss of
intensity by absorption ’).
ScHusTER *) was the first to discuss in an ample way the combined
influence of scattering. absorption, and emission of light in extensive
masses of gas. Basing his conclusions on Kircanorr’s law, and making
various suppositions as to the ratio between the coefficients of absorption
and seattering, he examined into the circumstances that would make
an atmosphere of a certain depth produce either dark or bright
spectral lines.
1) Rayveies, in deducing the formula (9), has not taken this into consideration ;
his result only applies to the attenuation which the origina! beam suffers by
scattering, and does not include the scattered light itself.
2) Scuuster, Radiation through a foggy atmosphere. Astroph. Journ. 21, p. 1, (1905).
( 892°)
The way of attacking the problem was
as follows. Let an atmosphere of thickness
¢ be irradiated by a_ surface S/S, (fig. 3),
which per unit emits a quantity of energy
S within the limit of wave-lengths 2 and
2+ 2, and uniformly distributed over all
directions. Now Scuuster begins with cal-
culating the change which the total flow of
Fig. 3 radiant energy suffers in a thin layer dv of
that atmosphere. The layer receives from the left a quantity A per
unit surface (whieh in general must be smaller than 5, although it
includes, besides the radiation directly coming from .S,S,, also the
radiation emitted by the part of the atmosphere lying between JSS,
and the layer dv). Of this quantity A the layer absorbs xAdzx *), and
scatters sAdr, the latter part not being lost as radiant energy of the
given wave-length, but proceeding half to the right, half to the left.
From the right side the layer receives a quantity of energy Bb per
unit surface (composed of seattered light and proper radiation due
to the outer part of the atmosphere); it absorbs xbdz and scatters
sBdv, of which */, sBdxv goes to the right and '/, s6dx to the left.
‘he layer also radiates energy in both directions, amounting to
ziile, if FH represents the emission power of the black body within
the chosen limit of wave lengths and at tbe temperature of the layer.
Collecting these effects, one obtains the equations
dA ee éf
pete ae tint 1 aos“)
dB ee 1
7 HBB) + 5 s(B—A) . » as GET
av “
If now the temperature and the composition of the atmosphere
are supposed to be everywhere the same, so that /, x, and s may
be considered as constants, A and £6 can be solved as functions of x.
Let «w be reckoned positive toward the right, and the origin of
coordinates taken in the outer surface of the medium, then we shall
find the emergent radiation R equal to the value which A takes for
v=o, while at the same time we have 4=o0. Another condition
is, that for «= —#, we have A==S.
Performing the calculations, ScHusTER obtains
1) | am using here Scuusrer’s notation, and therefore must draw the reader's
attention to the fact, that the above coefficient % is not quite the same as that
. An
occurring in $2, §3and§ 4, but corresponds to the expression —_ . 7% of formula (12).
2
( 893 )
[1 +e)e a(zts)t | (l—a)e— 2 $5) 4] a 2(8 z E)
R = 2 ——— —r
(14)
x
where @ means Va 5
xs
In order to study the nature of this raiher intricate relation,
Scuuster assigned a number of different values to the ratio =~
s
and to the produet s.¢, and constructed several diagrams in which
_R E ,
the corresponding values of | and — were taken as ordinates and
’
Y
abscissae respectively.
As to these results, and a great many other interesting conclusions,
we refer to the original paper.
ScHUsTER made no special assumptions connecting ~ and s with
frequencies.
It les in our line to bring the selective character of these
coefficients to the front. The simple relation to which (14) may be
reduced for waves suffering no absorption at ail, will prove very
important and useful in this connection. Denoting by R, the value
which R assumes for x = 0, we obtain‘)
2
Serene © ids Bo co oe | ((ilby)
Let us call to mind, before applying this formula, that in deducing
(14) Scucsrer supposed the temperature and the composition of the
mass of gas to be uniform, and the intensity of the radiation not to
depend on the angle between any direction considered and the
normal to the radiating surface. These conditions evidently not being
satisfied in the atmospheres of celestial bodies, (14) and (15) only
give a first approximation; the influence of the said circumstances
will afterwards have to be separately discussed.
In §4 we introduced the hypothesis that the first term of the
damping parameter vanishes at a short distance from the proper
frequencies, which means that the region of real absorption is
confined to the middle-part of each dark line in all cases, where the
conditions are such as to make scattering effects appreciable. On
that score we assume the equation (15) to hold good for the rest
of the spectrum, including — in the case of the solar spectrum —
the outer parts of the Fraunhofer lines.
Equation (15) shows that, with increasing thickness ¢ of the
1) Scuuster, le. p. 6.
( 894 )
scattering layer, the intensity of the emergent radiation diminishes,
but at a slower rate than it would do if seattering acted in the
same way as absorption. Putting for instance, s. {== 98, we obtain
R, — 0.028; and then doubling the layer, we find) Ry = O;00Ri
while, if in the original layer an equal loss of 98 pereent had
been caused by absorption, the layer of double thiekness would only
have transmitted 0.0004 5.
In a vast mass of gas, like the solar atmosphere, even an exceed-
ingly small absorption-coefficient would suffice to produce a very
sensible attenuation of the light. We therefore think if much easier °
to understand the narrowness of most of the Fraunhofer lines, and
their appearance in general, if we assume the absorption coefficient
to vanish at a very short distance from the middle of each line, so
that in the rest of the spectrum the distribution of the light only
depends on scattering *) and other influences (refraction, diffraction, ete.).
Our confidence in the validity of the hypothesis is, however,
chiefly based on the fact, that it enables one to explain concisely
and in mutual coherence a great many astrophysical phenomena, e.g.
ihe systematic displacements of the Fraunhofer lines, and, if also
refraction effects are considered, several irregularities in the behaviour
of the lines, together with many particulars revealed by the spectro-
heliograph.
Let us now substitute the value of the scattering coefficient as
given by (10) into the equation (15); it thus becomes
3H
, S
relent A Tek?
We wish to investigate how R, varies with 2. If however, we
only consider a small part of the spectrum at once, comprising no
o o . =
more than a few Angstrém units, we are free to treat 4‘ and 5 as
constants, and may write
a
ee eee aS ar
Bie ac i 33 Dee es 6 (CG)
1) The question may arise whether there are perhaps indications from which
one might obtain some idea about the magnitude of scattering effects, reasonably
to be expected in a gaseous medium of the dimensions of the solar atmosphere.
Now, according to RAYLEIGH’s theory, the average sunlight loses about 5 °/p of
its intensity by molecular scattering in passing through our terrestrial atmosphere.
Substituting Rj=0,95S in our formula (15), we find s.t=0,1. If we make the
very rough estimate, that the solar atmosphere is 50 times as thick as the
atmosphere of the earth, and has the same average densily, we must write for
the sun: s.t—5, and, consequently, Rp =*/; S. This is not an unreasonable result.
lt proves that even with a much smaller densily the solar atmosphere would be
able to produce sensible scattering effects, especially near absorption lines.
.
a ae
(8955)
The constant % is proportional to the density of the medium, to
the thickness of the layer, and to the average mass per scattering
particle. The greater each of these quantities is, the smaller will be
the intensity of the emergent light (for any value of 4). The only
quantity strongly variable with 2 in the smali spectral region consi-
dered, is the factor R*, in ease there is an absorption line.
nal
The upper part of fig. 4 represents R= - oe function of 2 ').
The origin of co-ordinates corresponds to the wave-length 2, of a
free vibration; the line P, P,, having the approximately constant
ny —I : =e
ordinate — Te would be the dispersion curve if there were no
absorption line at @,.
Supposing ¢ to be sufficiently great, and
ft not too small, we may, in the deno-
minator of (16), neglect @ in comparison
with 4f*; so R, is about inversely pro-
portional to f°. The light is therefore
more weakened by scattering on the red
side than on the violet side of the absorp-
tion lines, if (as supposed in the figure)
we have n, > 1. With very strong lines
this difference will, however, partly be
neutralized, because, according to § 3,
the minimum of the refractive index sinks
further below m», than the maximum rises
above 7
0°
Taking this into consideration, and
preliminarily fixing our attention on the
Fig. 4. effect of scattering only, leaving that of
absorption aside, we may represent the intensity of the emergent
light by a curve of the shape d, d, d, d, d; (fig. 4, lower part).
The top d, (corresponding to = 0) does not coincide with 2,, but
is a little displaced toward the violet. If, therefore, one would imagine
the region between d, and ¢/,, where the loss of light due to seatter-
ing passes through a minimum, to be an “emission line’, one would
have to assign to it a smaller wave-leneth than to the absorption
1) In this figure A increases from the left toward the right; the succession of
the kinds of light is therefore opposite to that in the figures 1 and 2, where the
frequencies » were chosen as abscissae.
( 896 )
line, and, applying Dorrunr’s principle, would conclude that the
radiating vapour moves toward the observer.
Properly speaking, we are not allowed to apply the formulae (15)
and (16) to all waves between d, and d,, for where x is not equal
to zero, equation (14) should be used. Let us suppose that only in
the middle part of that region x has appreciable values; then .we
probably shall obtain a fairly true intensity curve, when subtracting
the ordinates of an absorption curve (supposed to be symmetrical with
respect to OO’) from the ordinates of the displaced, unsymmetrical
euarve d, d, d,. The result is a sharp drop in the intensity curve,
representing a narrow dark line in the spectrum, whose “centre of
gravity’ is somewhat displaced toward greater wave-lengths (with
respect to 4,), and which is partly caused by absorption, partly by
scattering. If one should mistake this line fora mere absorption line,
its displacement toward the red would make one think, that the
absorbing vapour recedes from the observer. *)
The above particulars which, according to our theory, the dis-
tribution of the light in a wide dispersion band must show, bear a
striking resemblance to the phenomena really observed by CHARLES
KE. Sr. Joun?) in the calcium lines /7 and A’ of the solar spectrum.
And if, besides the consequences of anomalous scattering, we also
consider those of anomalous refraction (not noticed in this paper), the
agreement between the results of theory and of observation proves
to extend to almost every detail of the phenomena described by
St. Jonn. So it is possible to explain the rather intricate pecularities
exhibited by the components /7/,, H,, H,, X,, A,, A, of the well-known
broad calcium lines in the spectrum of the various parts of the soiar
disk, without having to admit with Sr. Jonny, that there is a general
radial circulation of the calcium vapour going on in the solar atmos-
phere, with velocities that’ would amount to 1,97 kilometer per
second in the mean for the ascending, and to 1,14 kilometer per
second in the mean for the descending motion. I must refer the
faller discussion of these interesting observations to a subsequent paper.
With most lines of the solar spectrum the total region of the
dispersion anomaly, from d, to d,, is so narrow, that the particulars
concerning the part included between d, and d, escape our obser-
vation. What then remains visible, is only the asymmetry of the
1) In a former communication (Proc. Roy. Acad. Amst. XIII, p. 10; Astroph.
Journ. 31, p 428, 1910) I wrote that the central part of the K-line, the true
absorption line, cannot be displaced by anomalous dispersion. | did not yet realize,
at that time, that even the central line might be an impure absorption line.
9
2) Cuartes K. Sr. Joun, The general circulation of the mean and high-level
calcium vapor in the solar atmosphere. Astrophysical Journ, 82, p.388—82 (1910).
(tear 3)
dispersion bands enveloping the absorption lines. How the systematic
displacements of the Fraunhofer lines toward the red, the obliquity
of the lines in the spectra of sun-spots, and some other phenomena,
may be explained from this point of view, has been shown in former
publications *).
Anatomy. — “Notes on the trechlear and oculomotor nuclei and the
trochlear root in the lower vertebrates’. By Dr. W. G. Hur.
(Communicated by Prof. L. Bork).
(Communicated in the meeting of January 28, 1911).
In the course of the past year [| made several observations regard-
ing the oculomotor and trochlear nuclei and their roots, in Petro-
myzon, Lophius, Gadus, Hippoglossus, Rhombus, Pleuronectes,
Selache maxima and Scyllium Canicula. The results of my researches
ean be best demonstrated by comparing the relations of the said
nuclei in Petromyzon, Selache, and Lophius.
Riv
E ____
H Nu IZ
Nu. Ot
?
——li : i Se BL
LE LE
,——— ae
Ril Ram a
Fig. 1. Petromyzon.
Fig. 1 shows the topographic relation of the oculomotor nucleus
and root, the trochlear nucleus and root and the motor V and VII
root in Petromyzon.
As will be seen from this figure, the oculomotor nucleus in this
animal lies partly on the level of its root-entrance, partly behind.
The principal nucleus (Fig. 7), the only HI nucleus aecording to
some investigators, lies with its dorsal edge not far from the acquae-
duct. Whether the so-called “ventral Ill nucleus” be a IIL nucleus
or not, I will not state positively. Its topography speaks strongly
for this view, as can be seen in Figs. 1 and 6. The cell-type is,
however, somewhat smaller than that of the dorsal nucleus. I have
not been able to obtain sufficient certainty about the course of its
axis-cylinders to enable me to decide this question. *)
*) Proc. Roy. Acad. Amsterdam, XII, p. 266 and 466 (1909); XIII, p. 2 (1910);
Les raies de Fraunhofer et Ja dispersion anomale de Ja lumiére. Le Radium,
t. VII Oct. 1910.
*) This cellgroup is regarded by Antony, Jounsron, and Scuriuine as being a
part of the Ill nucleus, but by ‘TrRersakorr, on the other hand, as a cell group
independent of the oculomotor.
( 898 )
In the trochlear nucleus it is conspicuous that this lies very
dorsally, above the aquaeduct in the velum (Fig. 8), as has been
deseribed by Scnm1ine*) and observed by Tretsakore *) in Ammocoetes.
The further topography of this nucleus shows that it lies nearer
the trigeminus root and closer to the trigeminus nucleus than to the
nucleus of the II nerve. Moreover the trochlear nucleus lies 7 toto
behind its root-end (Fig. 1 and Tretsakorr |. ¢.).
Fig. 2. Selache.
If we compare these relations with Fig. 2, which represents the
topographic relations in Selache, we immediately find a difference
in the position of the oculomotor nucleus, for the nucleus lies consi-
derably farther frontally than in Petromyzon and surpasses the frontal
boundary of its root (see also Scyllium, fig. 9). A ventral HT nucleus
does not appear here, all the cells lie in the upper third part of
the mid-brain basis (fig. 10). Still greater are the topographical
differences shown by the trochlear-nucleus and its root in com-
parison with Petromyzon. The trochlear nucleus no more lies
dorsally from the aquaeduct m the velum, but to the side of the
aquaeduet, practically under it, (fig 2). The nucleus is larger than
in Petromyzon. A part of it still lies behind the root-entrance,
another, much larger part lies in front. *)
The distance from the IV nucleus to the V_ root is greatly
enlarged, and the shifting towards the Ili root is so pronounced
that the II and IV nuclei partly overlap each other or pass into
each other (Figs 2 and 9).
1) Senne: Das Gehirn von Petromyzon fluviatilis. Abhandl. der Senckenber-
cischen Naturforschenden Gesellschaft, vol. 380 p. 441 1907.
2) Trersakorr: Das Centralnervensystem yon Ammocoetvs. II. Das Gehirn. Archiv.
f. Mikrosk. Anatomie vol. 74 p. 7135 1909.
8) The topography of the IVth root and nucleus is not the same in all Selachii.
Here I take Selache as object of demonstration because it seems more fit for com-
parison than Scyllium. Moreover our preparations of Sceyllium did not allow us to
fix the limits with so much certainty as those of Selache. (Added in the English
translation).
( 899 )
I wish here to say that the great distance between IV nucleus
and quintus-root is not to be attributed solely to the frontal shifting
of the former nucleus. The isthmus in the Selachian is much more
extended than in the more compressed brain of Petromyzon') and
likewise more than in the Teleosts. That, however, a considerable
frontal shifting of the trochlear-nucleus has taken place is also appa-
rent from the facts that a great part of the nucleus now lies in
front of its root-entrance, and that the HI and IV nuclei overlap
each other for a part, while in Petromyzon there was a large gap
between them.
Thus we find in these Selachii a strong frontal shifting of the IV
nucleus as compared with Petromyzon.
Fig. 3. Lophius.
Passing on to the relation in Teleosts, I refer to Fig. 38, in which
the topographic relations of Lophius are given. Here in the oculomotor
nucleus a great difference is noticeable as compared with Selache
owing to a part of the III nucleus having undergone a strongly
ventral shifting (Figs. 38, 11, and 12).
This ventral shifting should not surprise us, for if is known that
the abdueens nucleus in these animals also occupies a ventral posi-
tion. It is highly probable that here too, the strong development of
the ventral tecto-bulbar (optic) reflex tract is the cause of this dis-
placement which, for the decussated reflexes also, may perhaps find
support in the facet that the place of the lowest point of the nucleus
agrees with the ventral decussation level of the above-mentioned
reflex-tract, which lies (as we know from pw LANGn’s *) researches)
principally efore, partly on the level of the III root entrance and
1) The compressing of the Petromyzon-brain is also conspicuous in the fore-brain
to which Scorr has already referred. (Journal of Morphologie Vol. 1, p. 258).
2) Kappers. The migrations of the V, VI, and VII nuclei etc. Verhand. der Kon.
Akad. v. Wetensch. Vol. 16, 2de Sectie.
3) De Lancs. The descending tracts of the corpora quadrigemina. Folia Neuro
biologica. Vol. Ill, p. 644.
( 900 )
there sends out a series of fibres to the Ili nucleus (compare also
pincer and WALLENBERG ‘)).
In connection with the more frontal migration of the dorsal nueleus
which was found in all Teleosts, | may recall here the faet that
pe Lance found the decussation of the dorsal tecto-bulbar fibres also
more frontal than the decussation of the ventral set.
Regarding the IIL root I will mention that a great number of
decussating fibres originate from the posterior part of the IIT nucleus
bordering on the trochlear nucleus, which is interesting in connection
with the fact that the IV fibres have also a decussating character.
The trochlear nucleus shows us a further stadium in the process
already indicated in the shark, viz. the frontal shifting of its cells
which here lie entirely in front of their root-entrance. Although this
may partly result from a backward displacement of the root in some
Teleosts, a more frontal shifting of the TV cells is also very probable,
as is seen from the fact that the IV nucleus in Lophins has also a
more frontal position in regard to the Il root and V root and there-
fore, with regard to these points also, the shifting of the IV nucleus
can be aftirmed, equally in all Teleosts. (Figs. 3 and 11).
The position, which the IV nucleus occupies with respect to its
roof-entrance in the bony fishes is strongly suggestive of that in human
beings (cf. MarpurG *) where the nucleus also lies entirely frontad
thereof. It has been found by van Va kunpure *) that this secondarily
produced relation is sometimes shown by a cauda/ remnant of the
IV nucleus, which he designates ‘“‘nucl. 1V posterior” (ef. JAcoBsoun’).
With regard to the trochlear-root the following point may be
mentioned.
Earlier investigators had already observed that the trochlear-root
traverses the brain-stem with 2 roots (Salmo, Haiur*) Gadus, Kap-
pers *)) in some bony-fishes in contrast to other bony-fishes (e. g.
‘) Vorlesungen 7t¢ Auflage. — Beitviige zur Kenntnis des Gehirns der Telecstter
und Selachier. Anat. Anzeiger, Vol. 31, P. 369.
*) Marsure, Mikroskopisch-topographischer Atlas des menschlichen Zentralnerven-
systems.
8) CG. T. van Vatkenrure: These Proc. June 25, 1910.
4) Jacopsonn, Verhandl. Preuss. Akad. 1909.
») Hatter. Vom Bau des Wirbeltier-gehirnes. Morphologisches Jahrbuch Bnd.
26, 1898, p. 508. 1 cannot affirm however Hatumr’s statement that a part of the
IV root originates from the Purkinje-celis of the cerebellum. Nor did I see a
“kontinwierliche Zusammenhang dieses Kernes (LV) mit dem rostralwiirligen Ende
des oberen motorischen Trigeminuskernes” (I. c. p. 505).
‘) Kappers. The structure of the Teleostean and Selachian brain. Journal of
Comparative Neurology. Vol. XVI, 1906, p. 62.
J
-
a?
(901 )
Lophius). The exact course of both these roots was, however, never
clear before.
As I had at my disposal some frontal and horizontal series of
Gadus and other fishes, I was able to trace the whole system with
fairly great exactness and arrived at the following conclusion.
In Lophius piscatorius the decussation of the trochlear root-fibres
takes place in a fairly simple way. After their origin in the trochlear
nucleus, the fibres pass in the form of one compact bundle closely
round the aquaeduct upwards, and cross im toto on one and the
same vertical level, the decussation occupying about 6 sections of
25 ga, but not more; a difference can only be observed between the
fibres mutually in so far as some decussate closer to the aquaeduet,
others cioser to tie surface of the velum, a few even after the exit
(somewhat as in Scheme & fig. 4).
In Hippoglossus this relation is rather
more complicated, owing to some of the
fibres following a pathway separated from
the others. Before proceeding to decussation,
these fibres (about half of the total number) pass
frontally into the valvula cerebelli; then only
do they decussate and after the decussation
they turn laterally, ran again caudally be-
tween the valvula cerebelli and its connec-
tion with the tectum, to appear at the height
of the original velum out of the groove
between mesencephalon and cerebellum
simultaneously with the other root-bundle
which has decussated on the original level
(somewhat as in Scheme c, fig. 4).
The impression is conveyed as if the
Fig. 4. anterior part of the trochlear-root and its
decussation were drawn frontally by the growth of the valvula into
the optic ventricle under fixation of the point of exit.
This dislocation is the most conspicuous in the case of the anterior
roct-half in Gadus, where the valvula protrudes somewhat farther
forward under the tectum (cf. Scheme d fig. 12).
Besides by the peculiar dispersion of decussations, the anterior
part of the IV root of this animal is also distinguished from the
posterior by the fact that if does not run directly round the aquaeduet
medially from the tr. cerebello-mesencephalicus, but runs outside that
tract (Fig. 11) as has also been observed by Kappers (I. ¢. p. 62).
That the frontal shifting of a part of the decussation is caused by
( 902) )
ihe frontal growth of the valvuia is clear. It does not occur in
animals without valvula (e.g. sharks), and in Lophius, where the
KE
= AN) RIL amt
——— <~ RIV post
Yr soo) ploot
SS be Bruton wand uv. d.omslag ploot
| — 1 Buittrwand da valuula 0H
Ue loop dea TM. workel m ce
Valvula Cenc6lhk
Fig. 5. Gadus.
valvula cerebelli is extremely small, there is neither any question
of a frontal shifting of a part of the trochlear fibres. Nevertheless
the conditions in this animal furnish us with the explanation.
The diagrams given here show how the said root dispersion is to
be deduced from the simple position. In type a (shark) the decussation
of the fibres occupies but a small space. As the velum is very thin
there is only one decussation. In 4 the velum is considerably
thickened, principally by the growth of the molecular and Purkinje
layer over it. (Type Lophius).
Although the decussation remains on one vertical level, a distinction
can nevertheless be made between the fibres which decussate close
to the aquaeduct, and those which decussate more or entirely on
the surface of the molecular layer.
In ¢ the molecular and Purkinje-layer has grown still considerably
further under the tectum opticum and exhibits more folds; a conse-
quence of this is the enlargement of the distance between the fibres
with a more peripheral and with a more central decussation, which
attains its maximum in ¢, practically agreeing with the conditions
as shown in Gadus.
(903 )
This diagram, at the same time, demonstrates clearly that the space
in which the frontal root decussates and runs back in a caudal
direction, does not lie zm the cerebellum but between the valvula
and the fold connecting it with the tectum.
Summing up my results, | can state the following :
Oculomotor nucleus.
The HI nucleus in the lower vertebrates occupies a more constant
place in the longitudinal-axis of the brain than IV nucleus. Never-
theless it certainly undergoes a distinct frontal shifting. In a dorso-
ventral direction the oculomotor nucleus of the Teleosts undergoes a
considerable displacement, which agrees with the ventral displacement
of the abducens nucleus in these animals.
Trochlear nucleus and root.
The trochlear nucleus in the lower vertebrates exhibits still greater
differences in its position with regard to the longitudinal-axis of the
brain. In Petromyzon it lies at a great distance behind the III nucleus
even behind its own root-entrance, on the level of the trigeminus
root-entrance, as has also been proved by TrurJsakorr for Ammocoetes.
Moreover it lies more dorsally, above the aquaeduct in the velum.
In the Selachi the nucleus lies at a great distance from the
trigeminus root and close to the IL[l nucleus, passing into the latter.
In Selache it extends partly behind, though for the greater part in
front of the IV root-entrance. Moreover, it has come to lie under
the aquaeduct. In Teleosts the frontal shifting has reached its maximum.
The nucleus lies entirely in front of the TV root-entrance.
In some Teleosts the trochlear root undergoes a peculiar spreading
in bundles, e.g. Gadidae and Pleuronectidae, owing firstly to the
root being split into two parts before decussation by the passing
through of the tr. cerebello-mesencephalicus; secondly, the part whieh
runs round outside that bundle is drawn forward by the frontal
growth of the velum that grows out to valvula cerebelli, in conse-
quence of which it decussates more frontally, and then again runs
caudally between valvula and its connection with the tectum.
This severing of the decussation levels also explains the splitting
of the trochlear root into two roots at the exit, which until
now has not been found in fishes without valvula (sharks) nor in
those bony fishes where the valvula is very small (Lophius).
59
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 904 )
Bacteriology. “Acoli fying air- and ricebacteria the cause of
Polyneuritis gallinarum’. By J. WH. FB. Koursruees, (Commu-
nicated by Prof. C. H. H. Spronck).
(Communicated in the meeting of Januari 28, 1911).
The above title is at the same time a hypothesis which T intend
to prove in the following pages.
It is a fact generally known and acknowledged that the discovery
of Polyneuritis gallinarum by Etikman, classified the so mysterious
Beri-Beri in general with those phenomena that can be elucidated
by experimental investigation. That Polyneuritis gallinarum belongs
to the same group of diseases that includes human Beri-beri was
likewise acknowledged by nearly all investigators; consequently
experiments with poultry were made im order to learn how to fight
the human disease.
By following the way taken by KIJKMAN, many investigators have
brought to light a great number of facts, and yet the causa movens
of the disease continued to be as mysterious as before, whosoever
supposed that he had discovered it, might be sure that asubsequent
investigator would declare it to be harmless.
In 1901 I was experimenting in Prof. EiskMan’s laboratory about
the autosterilization of the small intestine, and, as EtsKMAN was at
the same time engaged in experiments regarding Beri-beri, this induced
me, in order to study the intestine-flora of chickens, to examine,
for economy's sake, the intestines of those chickens thad had died
of Polyneuritis gallinarum. As I examined however likewise some
chickens that had been killed, I soon remarked that the intestine-
flora and the intestine-sapreaction of these two groups of animals showed
very apparent differences. Since that time | became convinced that
the Beri-beriproblem should be studied from the intestines of poultry.
Several investigators indeed have pointed out that presumably Beri-
beri is caused by poisons formed, during digestion, by micro-organisms
in the intestinal canal’). It was however astonishing that nobody
consequently chose the intestines and their flora as point of issue,
and that, if this was oeeasionally done (DusrvrL, Wrient it had
no result whatever.
On account of my return to Java I could not continue my inves-
ligations, but constantly, there and afterwards in Europe, I har-
boured the design of applying this method of investigation. Not
1) EukmMAN, LAon, MAurER, WricHt, Herzog, Jranseitur, VAN GoRKOoM.
(905 )
before Oct. 1910 1 could accomplish this design, when Prof. Sproxck
was kind enough to place at my disposal a room provided with
all that was indispensable for such an investigation, to be used as a
laboratory. I set high value on the fact that I may add to this that
Prof. Spronck is quite willing to declare that the nature and course
of my investigations remained entirely unknown to him.
In order to examine chickens suffering from Polyneuritis gallina-
rum [ had first to make healthy chickens ill, and sueceeded in doing
so, according to the method taught by Ekman i.e. by compulsory
feeding with white entirely prepared rice.) After 18 or 19 days
every chicken thus fed became ill, showing the wellknown symp-
toms of Poiyneuritis gallinarum. *)
During these experiments | observed in the first place that during
November and the first half of December the rice, neutral after
sterilization,®) grew sour within a few hours when it was exposed
to the air. The tirst thing I wanted to know now was: Why does
rice acetify?*) Nobody could give an answer to this question,
not even Prof. Bryranxck of Delft, who kindly listened to my
questions but felt even inclined to doubt the fact; I myself could
however doubt no longer, for I saw that rice kept, after the steriliz-
ation, in well shut vessels remained neutral, whilst I saw it turn
sour when it was exposed to the air in the different rooms of this new
laboratory, where never before experiments concerning fermentation
had been made. The rice turned also sour in the crop and in the
intestines of chickens. From the above it appears that the rice did
not turn sour by a simple chemical process. Consequently the rice
must turn sour either by bacteria of the intestines or by bacteria
of the air, or by both. By a series of experiments the obligate bacteria
of the intestines of chickens were soon excluded, consequently had
the acetification to be explained by the bacteria of the air. Now |
made my investigations in that direction, but it was anything but easy to
1) In order to exclude however any idea of spoiled rice, the rice was sterilized
at 120° before it was used. By so doing I obtained likewise a greater conformity
with the often sterilized articles of food on board sailing-vessels that are so often
accused of being operators of Beri-beri
2, Frequent thin defecation, emaciation, paralysis, cyanose, dyspnoe (M1JKMAN).
3) Uncooked not sterilized rice has always a feebly acid reaction.
4) As sour fermentation was then for me only a sound to which I could not
attach any idea, I applied in the first place to the vinegar-works ‘de Roos” at
Amsterdam, where Mr. O. Wixrortu in the kindest way furnished me with inform-
ation and placed at my disposal the literature about vinegar fabrication; Mr.
H. VLAANDEREN, a well known dealer in groats here, informed me about the diffe-
rent soris of rice, the way of preserving rice etc. etc, To both my sincerest thanks.
oo*
(906)
isolate these micro-organisms that acetify riee among the mixture of
moulds, fungi, and bacteria that fall out of the air on wet sterilized
rice‘). This micro-organism however was found after all. It is a
small, short vod, having great resemblance to the Colibacillus of
ihe intestines. The isolation was rendered still more difficult because
this little rod is very polymorph, and because a special medium and
special breedingtemperature are required to obtain a good result.*)
This bacillus acetifies within 24 hours neutral sterilized rice, which
but for this bacillus always remains neutral.
Just now I have compared it to Colibacillus, on the other hand it
reminds me of the vinegar bacilli by its polymorphy. The more
so, because it possesses the peculiarity, demonstrated by Brterinck
in some vinegar bacteria, of showing on some special media easily
deviating and hereditary qualities. So e.g. it is not difficult to deprive
it of its power of exciting fermentation. According to BrtErtnck
there are’ also vinegar-bacteria that do no longer acetify, and must
have originated in acetifying ones. Only on fit media, and when
cultivated at the required temperature, and constantly having anew
opportunity of acetifving rice, it is kept in good condition. It cannot
be kept in rice, as it soon dies in the acid it has produced itself.
Grow and multiply the bacillus does on the other hand on every
medium that is not too sour, even though it afterwards dies or
modifies itself in many of them. After domestication it accom-
modates itself to altered circumstances as to a feeding that was first
refused or to a temperature at which in the beginning it was killed.
Consequently we have here an exceedingly resisting bacillus, which
could be cultivated in November and December in the whole
laboratory. When however in December the temperature reached
1) At the present moment this is not difficult, simce | found out that moulds
and fungi only multiply on rice, when the rice has obtained an acid reaction
by the bacterium causing rice to turn sour. Consequently the moment when the
rice that is at first neutral, begins to show a feeble acid reaction, must be
carefully observed, then, in most cases, pure cultures of the bacillus acetifying
rice will be obtained by inoculation on specially prepared ferment. This is still
easier in winter when the air of the room that has grown perfectly dry by the
heat of a stove so that scarcely any moulds and fungi are found in it.
2) The first inoculation from sour rice very often had not the desired result on
the common alkalic or acid media at 37°C., very often they do grow, but lose their
power of fermentation. Rice which is in the first place indicated as a medium
cannot be made into a transparent medium, On ferment and malt the best results
are obtained at a lemperature of 17—23° C. On ferment results are obtained to
a temperature as high as 40°, on malt not. 1 owe the prescription for malt to
Prof. Bertserincx, the recipe for ferments was used and accidentally tried in this
laboratory. Only on rice, glucose and malt acid is formed,
a
(907 )
oceasionally and even repeatedly the freezing point, the bacillus
disappeared almost from the air. It became so rare that cooked
white rice could be exposed from 5 to 6 days to the air without
turning sour’). Did it do so in the end, then the same short rods
were always isolated from the rice.
On account of its polymorphy, and soon diminishing efficacy on
artificial media, it was however desirable for me to dispose of a
source from which every day new generations could be isolated.
In December and January the air no longer produced them. As
this bacillus seemed to have a special affinity for rice, the idea
oecurred to me that it might perhaps be found on dry grains of rice.
For this reason dry grains of rice were sown on sterilized neutral
rice and really every grain of rice*) proved to be a source of acid,
in which the above mentioned bacillus was found. It seemed strange
that this bacillus can live in such a perfectly dry grain. Therefore
one might have surmised that it sticks perhaps only accidentally on it,
as an air-bacillus. Further the finding of bacteria on or in all fully
prepared grains of rice reminded too much of those investigators
(van Digren ete.) who attribute all sorts of evil consequences especially
Beri-beri to feeding with lone kept, peeled grains. Both considerations
induced me to examine unpeeled rice (gaba) in the following way.
In order to exclude all air-bacteria every grain of rice (gaba) was
separately passed several times through the gas-flame, then the coarse
yellow skin, and the fine white one under it is charred, and only
the interior part of the grain remains white. The grains are now
ground in a sterilized mortar, and this mixture of carbon and white
amylum is inoculated on neutral sterilized rice. Then it appears that
the acetifying bacillus lives likewise inside the unpeeled grain of rice,
and continues to live, when the rice is treated in the way we have
just deseribed, for the neutral rice grows sour, and the bacillus appears.*)
1) If this investigation had begun as late as December, I should never have
observed the acetification of the rice, and consequently never have obtained the
results | have come to now. Until now | have not yet been able to capture the
bacillus from the open air, and it is by no means impossible that it is more correct
to regard it as a wall-bacillus living inside the houses on the walls and spreading
itself thence into the rooms.
2) Common rice, white not glossy rice of Java, Moulmein, Rangoen and
Bassein harbours this rice-baciilus, the latter more than the other, or a more
vigorous variety than the other sorts.
3) It is an interesting problem, when this bacillus enters into the rice, whether
in the fields, or after it has been taken to the barn. This question must be solved
in India or Italy. Perhaps rice cannot ripen without bacteria. What part do these
bacteria act? These might be questions of as great agricultural interest as the
( 908 )
I followed the cowse of my own investigations by indieating only
one bacillus, this is however less exact. Accidentally the before-
mentioned short rod had first drawn my attention, and as every
bacteriologist is anxious to work with pure cultures, it was every-
where isolated, in doing which | was often hindered by a certain
lengthened rod that made its appearance in the cultures, for which
reason several cultures were disapproved of. It appeared afterwards
that in every portion of acetified rice and in every dry grain of rice
both bacilli are found, which both make rice sour; it seems conse-
quently that they live as in symbiosis, or support each other. Since
that time I often worked with this mixture, indicated by nature,
which appears to have a much greater vital strength *).
If one keeps the rice of the noon-table in India till evening it
may easily have turned sour, which proves that these bacilli aceti-
fying vice occur likewise in the tropical regions; an investigation
ought to be made whether théir appearance is likewise subject to
season or the state of the weather *).
[ should like to communicate here what acid was formed by
this fermentation. Dr. Srvan was kind enough to offer me to isolate
and determine the acid; this investigation however is not yet finished.”)
I have hkewise to thank Dr. Staan for the information that in
order to neutralize the acid produced by bacilli from 20 grams of dry
a a re aw > n 7 .
eras of rice in 7 days 24.6 cub. em. 19 NACH was required.
This investigation into the fermentation of rice was consequently
finished, and relying on the reports of EyKMAN and others that rice
turns sour in the crop of chickens, I passed over to the following
working-hy pothesis. The acetifying agens in the crop and intestines
well-known nitrogen-binding-bacteria for the roots of legumimonsplants (BEIERINCK).
As Bert-beri does not occur in Suriname, | shall try to obtain rice from that colony
for examination.
1) Now the, question occurs to me, if not many of the unsuccessful results |
obtained with media and breeding temperatures are to be attributed to my cultivating
only with the short rod. Or are they after all two growing forms of the same
bacillus? The vinegar-maker Mr. WixrortuH told me that for his products he thinks
pure cultures unfit.
) A rice-acetifying-bacillus was isolated by Maurer (Medan). I am convinced
that his bacterium A, is closely connected to, if not identical with the one [isolated
at Utrecht. Maurmr’s culture perished alas! I shall repeat the experiments
deseribed by Maurer in order to ascertain how far the conformity goes. Rost
seems likewise lo have found a similar bacillus in 1910.
5) It is no Acidum lacticam (contra EykMAN) and no Acidum oxalieum (eontra
Maurer). Nor is it volatile for it does not diminish by sterilization.
= rt—“ CsOSCC
—— a
( 909 )
of chickens are not the common intestine bacteria, but the air-
bacteria, described above, which acetify rice. A series of experiments
followed from which appeared Ist. that the obligate intestine bacteria
do not acetify rice, 2°¢. that in the crop and intestines of chickens
that died from: Polyneuritis gallinarum the air-bacterium that acetifies
rice can be shown; 3'¢. that in acute cases of Polyneuritis the air-
bacterium can almost supersede the intestine-bacteria.
Another working hypothesis followed. As, by feeding with rice
Beri-beri presumptively results both in India and Europe’) from
poisons developing themselves during the digestion out of food, con-
taining amylum (EykMAN); as rice has a special affinity for the
above-described acetifying air-bacilli, so much so, that they are even
found in every dry grain: it may be admitted that these bacilli are
the generators of Polyneuritis gallinarum not in the usual infectuous
sense, but because they are pernicious to the body, when they tum
the rice sour (in the intestines), either by the acid itself or by
accessory products. If this supposition is correct, these bacilli must
be harmless at subcutaneous injection, but they must cause Polyneuritis
gallinarum when they are introduced. into the intestines together with
the food.
'f was soon shown that these bacilli, and even entire cultures
together, injected into the breast-muscles and into the peritoneum do
not cause Polyneuritis gallinarum *). The last and most important
experiment remained.
I communicated already above that my chickens fed with sterilized
rice, show after 18—19 days the well known symptoms of Polyneuritis
gallinarum; *) EykmMan who acted somewhat differently obtained the
same result.*) If now the bacillus acetifying rice is the generator of the
') A European Beri-beri epidemy was the one in the RrcHmonp-asylum at
Dublin. | do not know what food was taken there.
*) Nobody will be astonished at the fact that chickens lose their appetite, if for
days together 10- 12 platina loops of these bacteria are injected into their peri-
toneum, even physiological salt-solution would make the = ill. But they are not
attacked by Polyneuritis, and do not die. Afterwards I injected into the breast-
muscle which they could stand better.
5) The first week they receive grains of rice which are strown into the chicken-
house, soon they refuse this food, so that the 6th or 7tb day one must proceed
to compulsory feeding with sterilized rice-porridge.
1) EykmAn does not sterilize the rice, has the grains only grourd and mixed
with water, consequently the chickens receive the bacteria living in the grains of
rice into their crops, when these are still alive. This is most likely the cause
that EykMAN often obtains stagnation of food in the crops by expansion and
fermentation. | never had this result. Has the ground and moistened rice been kept
a long lime, it might occasion sudden death, as EyKMaNn often observed.
(910 )
disease, ehiekens fed with sterilized rice, and moreover with cultures
of these bacteria, must much sooner be attacked by Polyneuritis
vallinarum than the former, as these receive only such bacilli as
accidentally pass from the air into the crops;") whereas the latter
swallow with the rice entire cultures of these bacteria.
It appeared indeed that chickens, fed with sterilized rice and
cultures of acetifying rice-baeilli bred on ferment, showed already
on the 3° day symptoms of paralysis and cyanosis. The third
day they are sitting in the cage with paralyzed feet and bristling
feathers, blue combs, show soon dyspnoe and die the fifth day. A
dreadful diarrhoea was perceptible previously and the animals are
enormously emaciated in those five days, so that even the breast-
muscles have disappeared. All symptoms correspond entirely to those
whieh chickens, fed with rice only, do not show before 24 or 25%
day, but here they coincide in a short space *).
This experiment proved undubitably that the ai- and rice-bacillus
generating sour fermentation, isolated by me, can cause the symp-
toms of Polyneuritis gallinarum when it is introduced into the in-
testines of chickens.
The bacteria in question, the froth of the fermentation can be
observed post mortem everywhere in the intestinal canal, the bacteria
themselves seem sub finem to merge into the blood, and this faet
explains that formerly so often bacteria were isolated from the
blood of Beri-beri patients and chickens. Perhaps then already the
same bacillus was found, which however was always rejected as the
morbifie agent, because if was supposed that it was to be expected that
the morbifie agent, when brought into the blood, must cause Beri-
beri. It was not yet known that Beri-beri seems to belong to a
peculiar group of diseases that find their origin in micro-organisms,
and yet are no infectious-diseases in the usual sense of the word,
and are best characterized as fermentation-diseases. In these diseases
the morbid organism is only detrimental in the intestines and harm-
less in the blood. *). For the present this remains a theoretically
construed group, among which I classify Aphthae tropieae*), the
1) Or the very bacteria of rice with Eykman’s method. This is of course never
the case with*man, as he never eats raw rice. Yet | once saw a fanatical vege-
tarian do so, and I understand now why he perished from violent diarrhoea.
2) By adding fewer bacteria to the rice the process can be rendered slower.
%, This is the reason why pe Haan and Grisns searched in vain in the serum
of recovered Beri-beri patients, or in the serum and hydropericardial fluid of
patients for “complementsbinding.”” Neither did they find any in chickens.
') According to Dr. Maurer’s and my own investigations.
)
|
;
f
(29itEly)
disease of Bartow and = scorbut.’) May they not remain long a
theoretically construed group. Investigations with regard to scorbut
have already been taken in hand. Now we should be anxious
to know which fermentation-products generate the symptoms of
the disease, this however is the task of the chemist rather than
mine. At all events we have in the first place to wait for what
STAAL’S investigations concerning the acid that is formed, will
teach us.
Another series of experiments related to the facts, discovered by
wy predecessors, that chickens fed either with unpeeled rice or
with rice and raw meat, or with rice and Kadjang hidjoe ete.
do not become ill at all, or do so later.
When cultivating the acetifying bacteria, it appeared that they
develop themselves only in that part of the rice that by cooking
separates a pultaceous matter, which we call ‘starch’, and in India
tadjen*). This starch is analyzed by the bacteria into water, gas,
acid and perhaps unknown products. The more starch is formed
by cooking, the more luxuriously the bacteria grow in such rice,
the less starch, the less food for the bacteria, the less formation of
eas and acid.
Even by repeated cooking of rice the grains remain intact, the
starch has however separated from them, and makes the grains
stick together. and in these intervening spaces of starch one sees
the bacteria grow rankly, and change it into water in which at last
the grains float.
White fully prepared rice produces much starch, cooked gaba
(unpeeled rice) produces hardly any starch, sterilized gaba again
produces some more starch. The longer the unpeeled rice is cooked,
the more starch is obtained, and consequently it is to be understood
that (Grisns, Marsvusnira) padi cannot entirely protect against Beri-
beri. If one adds to fully prepared rice ferrihydroxid, eges*), spirits,
animal charcoal‘), fresh meat, much less starch is formed *). By
1) Nocut and Ho.sr
2)
2) To the rice starch-works of J. Duyvis | owe the communication that a not
unimportant part of the rice cannot be turned to starch, a considerable residue
remains which is sold as food for cattle, it contains 87,74 °/) of organic matter
(Sraat). The percentage of starch of the various kinds of rice is very different.
5) Marsusniva asserts that the addition of eggs to rice prevents Bert-beri.
') These least.
») Addition of these substances never impedes the growth of the bacteria and
the fermentation, though it 's inferior on accoant of the inferior quantity of starch.
(912)
anology I conclude that Kadjang hidjoe ‘) will have a similar preventing
influence on the formation of stareli. *)
Moreover it is by no means indifferent whether these substances
are mixed with the rice before if has been cooked, or after the
cooking has taken place..The starch that has been formed already *)
cannot be precipitated, either the starch that is in process of forma-
tion is precipitated, or its development is prevented.
It is very remarkable that the natives, when left to themselves,
never cook rice but steam it, whilst the steaming is variegated by
washing, the consequence of which must be that the starch dis-
appears, is washed away. Rice for prisoners and soldiers on the
contrary is cooked, and though one tries afterwards by evaporation
to give to the grains of rice the dry appearance that steamed rice
has, yet the starch remains in the food. The first group is
consequently guaranteed against Beri-beri, the other exposed to if.
The danger augments considerably, if one eats by preference cooked
or steamed rice, after it has entirely cooled down. On such rice the
acetifying bacteria of the air have fallen down, not only does it
smell sour, but it obtains that agreeable flavour reminding of fruit, a
consequence of fermentation that is highly praised by gastronomers *).
Food containing amylum in which few substances are found that
form starch guarantees against Beri-beri, and there exists moreover a
sort of starch from amyluin that ferments, but through which only
very little acid is formed. So our bacillus very easily produces
water and gaz from starch of potatoflour, but by this process only
a very small quantity of acid is formed. Consequently it is not strange
that with potato-flour EtsKMAN cannot excite Beri-beri °).
A controversy arose between EikMAN on the one hand and Gruns
with Horst on the other, whether Beri-beri can occur when feeding
with sterilized meat. I have not repeated these experiments but 1
draw the attention to the fact that our bacillus grows vigorously on
1) ROELPSEMA, Grins, Hutsnorr-Pon.
2) The influence of Kadjang hidjoe and rice-bran may however be quite different,
see below.
3) Kor this reason the extract of dedek, or the salts found in dedek added to
rice that has already been cooked, will not prevent Beri-beri (GRIgNS contra EIJKMAN).
') Tamil rice on the contrary which protects against Beri-beri stinks (FRASER,
Srayvon). It is submilted to a treatment by which the starch-substances — are
lixiviated, by this process the fermentation that gives an agreeable flavour is rendered
impossible.
») Sterilized potato-flour ferments somewhat quicker.
6) Nor is it strange that neither this flow nor gaba can absolutely protect
against Beri-beri (GRiJNS).
(913 )
sterilized meat, whilst it is quite superfluous to add anything to it ').
Instead of feeding-experiments | took fermentation-experiments.
Though I acknowledge that these need not cover each other
entirely, yet until now they supplied nothing that is contradictory
to the facts observed by feeding, so that my experiments perhaps
may explain these facts and plead powerfully for the suggestion that
Beri-beri rests entirely on fermentation processes *).
Moreover | think that it is of the greatest importance that these
bacilli are found much more frequently in-doors than out-of-doors,
that, in Europe at least, they are restricted to certain seasons, and
that very dry air makes them disappear.
This fact explains why Beri-beri is more frequent near the sea-shore
(VorDERMAN), with bad ventilation (VorDERMAN), in houses built in the
European way (v. b. Bure); that expeditions in woody, marshy
regions are notorious for the great number of Beri-beri patients
(Djambi). Wherever the local conditions are favourable for the
development, a so-called Beri-beri epidemy may break out, or a so-
called Beri-beri house or ship may be found. If a house is strongly
infected with these bacteria, the tenants can be attacked by Beri-beri
from inhalation, from swallowing dryly, from drinking water, though
they take their food (rice) ontside the building *).
As the cultivation on various media and at various-temperatures
taught me, how easily varieties may come into existence, and
that the fermentation-process is moreover promoted by symbiosis,
I suppose that varieties of this bacillus may exist that are extremely
malicions. They obtain this quality most likely in the following
manner. The bacillus must first accommodate itself to the medium,
1) A thick fleece of bacteria is formed at the surface of the fluid floating on
the sterilized juice without acetifying it.
2) It is by no means my intention to explain all symptoms, observed by mono-
tonous feeding, by the fermentation excited through the bacillus. The want of
nucleopotreides or nucleine (JeBBINK, NocHT, SCHAUMANN) may either predispose
or promote the disease or be in itself the cause of it. This nucleine theory is
not attacked by my investigations. A bridge might be built across, if it could be
proved that nucleoproteides are analyzed by fermentation. In that case fermentation
would not produce active destructive substances, but death would be caused by
depriving the body of the required food) This theory appears to me very
admissible, as up tll now, | could not succeed in making chickens sick by inter-
muscular injection of the pure fermentation fluid.
5) So m the building of the doctor-djawaschoolt at Batavia (1900) 80°/, of the
pupils who to k their meals outside the school became ill. Would perhaps new
walls offer a fit medium and this perhaps be the cause that rice turned so quickly
sour in this new laboratory? Brenriey was likewise of opinion, that the
generator of Beriberi must be a wall-bacillus.
(914 )
and the temperature of our intestines, when if has sueceeded in
this, and leaves our body with the faeces (vAN Gorkom), it will
operate much more strongly when it enters into another man’s body
(Wricnt). In this way, I think, I can likewise explain why the
disease seldom develops itself suddenly, and yet in other cases can
assume such an acute form (Djambi). In such extra-ordinary cases
it mocks all prophylactic measures, though they may be ever so
rational (HutsHorr Pon) *).
So far about the aetiology of Beri-beri. A single word more about
the therapy. The latter can be divided into prophylactic and causal
therapy.
We know already very much about prophylactic therapy. We
know that Tamil-rice and red rice usually protect against beri-beri ;
we know that a nourishment more in accordance with the European
usages suppressed Beri-beri in the navies of the Dutch Indies (VAN
Levent) and of Japan; Jepsusk has likewise shown in his dissertation
the great difference there is between the two methods of nourishment.
Here I shall only emphasize the fact that the native soldier, who is
much more subject to Beri-beri than the Huropean soldier, receives
in his food more substances containing amylum than the latter.
Moreover we know already, and the investigation lying before us
confirms it that for fighting fermentation, the way in which rice is
prepared is of great importance. One should always try to apply a
method by which the starch is washed away. Further one should
examine, if the starchy substances can be removed before the rice
is transported to the barn and peeled. Most likely the preparation
has much greater influence than the age after complete decortication
or the bringing into the barn of fully prepared rice (van Dipren
contra EYKMAN and GRtNs).
Other experiments have taught that the addition of certain
substances to the cooked rice prevent the appearance of the disease.
LaoHw mentions the side-dishes usually taken by the natives, others
praise especially kadjang hidjoe (HuLsHorr Por), EijkMAN rice-bran,
ScuAUMANN ferment. When cooked directly with rice these substances
1) Consequently | do not think strange at all that Wricur could make monkeys
suffer from Beri-bert by feeding them with rice and banana, which had been rubbed
on the floor of sick-rooms where Beri-beri patients were nursed, whilst subcuta-
neous injections remained unsuccessful (Hunrer, Kocn). Transportation of the
disease by ships and men to regions that had hitherto been exempt from Bert-
beri can be explained, if it may be admitted that rice in those regions did not
show ithe same fermentation phenomena, or that a specially virulent variely had
been introduced which had become extremely active on account of its passage
through the human body.
> eel
——
(915 )
/
mieht, as mentioned before, prevent the formation of starch, but if
I rightly understand the investigators, they did not act in that way :
consequently this explanation does not hold good. Moreover they
might hinder the growth of the bacilli or prevent fermentation. I
know by experiment, (hat these substances when alcalised do not
hinder the bacilli, they prevent the growth however undoubtedly
by the acid they contain themselves.
If on the contrary we admit that the symptoms of the disease
depend on the fact that the fermentation in the intestines does not
produce active poisons but deprives the body from feeding-substances
(Nocrr. Scuaumany) without which it cannot continue to exist, it
would be possible, that these were added again to the body by the
beans called kadjang hidjoe ete. This point requires further investigation,
Causal therapy will try to fight the bacilli’) and the fermentation
and its products in the intestinal canal. In this direction however
as yet no experiments have been made with the exception of those
with the above mentioned articles of food. Causal therapy can take
another road by counteracting the influence of substances that have
eventually crept into the blood, or by supplying such substances as
may have been withdrawn from it. | know that Prof. Eyxman is
making experiments in that direction.
In view of the observations of. my predecessors, of my own
investigations and of the fact that, in so far as I have hitherto
been able to apprehend, neither the injection of the bacteria, nor
that of the filtrate of acetified rice (interperitional or inter-muscular)
excites Polyneuritis in chickens, | must admit that the bacilli causing
fermentation deprive, from the intestine canal, the body of substances,
by which the quick emaciation must be explained. (500 gr. in 4 days)
at a slower process the symptoms of paralysis show themselves
first, but at all events the withdrawal of these substances ultimately
renders life impossible, and death is the consequence ’).
If really, as now-a-days is generally admitted, human Beri-beri and
Polyneuritis gallinarum is to be attributed to the same or akin causes,
1) Maurer thinks he can obtain this by acids (acidum Jacticum, muriaticum,
pbosphoricum). As the bacillus soon dies in acidiferous media, the acid produced
by the bacillus itself applied in great abundance might act as a curative.
*) In all therapeutical experiments it is strictly required to make with HULSHOFF
Pott a sharp distinction between the symptoms proper of Beri-beri and the
subsequent consequences, on account of tiie degenerated nerves. Only against the former
we may expect to find an active remedy. Moreover not all that we remark in
chickens is applicable to mammals, as Houst’s experiments with rice feeding of
Cavyas have shown.
*) Yamacnwva is of opinion that the regressive metamorphosis is a consequence
of anaemia.
(916 )
it must be possible, in case of acute Beri-beri, to isolate such like
bacteria from the faeces of the patients. [tis however possible that
they perish in the rectum, as is the case with Polyneuritis of chiekens, in
whose whole intestine canal very often the acetifying bacilli are
exclusively found, and yet it is very difficult to deteet them in the
Coecum. Consequently we shall have to wait for a favourable case,
in which post mortem a fresh stomach and the small intestines can be
examined '), Should even under the most favourable conditions (acute
death in the first) stadium) the bacilli not be found, either human
Beri-beri and Polyneuritis gallinarum is not the same, or there are
different generators of the many diseases that have been classified
with the group Beri-beri. Yet I hope that, even in this case, the
results lying before us may be of use to ascertain the aetiology of
these diseases, which are, at all events, closely allied to Polyneuritis
gallinarum. Though a preliminary communication does not require
that the literature of the subject is reproduced in it, yet I have
taken account of the literature in order to avoid prejudicing prior
rights of others, and to control my own results. Prof. EyYKMAN was
kind enough to place his collection of separata at my disposal, for
which kindness I offer him my sincerest thanks. Much literature is
likewise found in the book of Dérck.
| foresee that, when my results are controlled, the fact that it is
exceedingly difficult to cultivate the bacillus pointed out by me, with
conservation of its virulence, will excite the most important criticism.
Moreover the bacilli (from air or wall) isolated from sour rice act
much stronger than those isolated from rice-grains. Other differences
depend on the seasons. Experiments with bacilli that have already
been moditied will of course give other results. 1 hope however to
succeed in finding a method enabling us always to dispose of vigorous
bacilli. The capriciousness or variability of the bacillus reminds us
of the fact that likewise the evidence of the symptoms of Beri-beri
with rice-feeding is exceedingly capricious, with regard to the earlier
or later date of its appearance, as the protocols given by HyKMAN
and Honst show (differences of three weeks). This resistance is attri-
buted to the animals, which may be true but has not been proved.
| give here these preliminary results, as my personal means do
not allow me to continue the required experiments with different
articles of food, and the different methods of preparing rice in every
detail. Perhaps others disposing of ampler means will be inclined to
repeat these experiments, and to bring them both here and in India
to the end wished for. Utrecht, 27 January 1911.
') According to vAN GorKoM, WRIGHT, DuBRUEL human Beri-beri always begins
with inflammation of the mucous membrane of the stomach and the intestines.
(#947 1)
Physics. «A new accurate formula for the computation of the
self-inductance of along coil wound with any number of layers.”
By F. L. Brre@anstus (Communicated by Prof. W. H. Junts).
For the accurate computation of the self-inductance of multiple
layer coils, different formulae are available in the case the cross
section ot the coil is a square, a circle or a rectangle. All these
formulae only give results of a bigh degree of accuracy, when the
cross section is not too large in comparison with the mean radius,
and besides for the rectangular section restriction is made, that the
length of the coil shall not considerably surpass this mean radius.
For the ease of a Jong coil or solenoid wound with many layers
of wire, to my knowledge no formula has been derived, which,
either in a closed form or in the form of a converging series, represents
the value of the self-inductance with a high degree of accuracy.
Lovis Conen') has derived for this case am approximate formula
of the following form:
{ 2c," SE ee Sere
18 — 4a*n?m
2
Iv 4a,” + 2 Tv
+. 82°n? }lim—D a + (m—2)a,? --... Ie a, + — «) +
8
1
eee an ia, 2 1) ( . 2 a, da ? (1)
- 2 |m(m—1)a,-- (r— MU ibe sree | ap —$— —— 100) —
- Va?t+eP
é ; da |
— 4[m(m—1)a,*+ (m—2)(m—3)a,? + ...]
wherein a, mean radius of coil a,,a,...= radius of the first,
second layer reckoned from the axis of the coil; da = distance
between two consecutive layers; /—= length, 7 = number of windings
per em. m= number of layers.
ConEN says that the results obtained with this formula are accurate
to within one half of one percent for a solenoid, whose length is
twice the diameter, the accuracy increasing as the length increases.
Apart from this moderate accuracy, this formula (which, moreover,
contains errors in the third and fourth terms) is very laborious for
numerical computations, when the number of layers m is large.
1) Lours Gonen, Bulletin of the Bureau of Standards IV, 383.
(918 )
Epwarb B. Rosa’) deseribes in the same part of the above inentioned
anual, a method for the accurate computation of the selfinductance
of a coil of any length wound with any number of lavers, which
he presumes to be absolutely correct and which is used by him to
check the results obtained by other formulae, especially Srmran’s.
This method, though based on a correct principle, will, if applied
in the manner used by Rosa, only then lead to very accurate results,
when the total depth of the windings on the coil is very small
compared with the mean radius.
In the following pages I propose to give the derivation of a new
formula, which, in a simple and for numerical computation very
convenient form, represents the self-inductance of multiple layer coils
with a high degree of accuracy in all cases in which the formulae
for short coils fail.
For the mutual inductance between two coaxial cylinders of equal
length Maxwen.*) has derived the following expression :
M=4x'n* a |l —2 Ac] : . . . . . (
lo
wherein
eA ae a hf = OAR Ae
= a Pa eee | ecu
oy 16.4? pe} GAAND | 98 Op
SON 8 A’ 4A" Bale F
_ je (18s
2048A5\ 7 7 ri ? r
rp=V A +P, A=rvadius of outer cylinder, a= radius of inner
cylinder, /= length, 2 — number of windings per em.
Te last term of « has been added to the derivation by E. B. Rosa *),
Generally the self-inductance of a coil is found by integrating the
expression for the mutual inductance between two elements of the
section twice over the whole area of this section.
In order to obtain this integral we suppose the solenoid to be
formed by a very great number m of layers. Indicating by a, the
radius of the outer layer and by da the distance between two con-
1) Epwarp B. Rosa, Bull. of the Bur. of St. [V 369.
2) Maxwett, Electricity and Magnetism, II, § 678.
2
3) BE. B. Rosa and L. Conen, Bull. of the Bur. of St. IL 305,
( 919 )
Fig. 1
secutive layers, we get for the radii of the consecutive layers:
a, =a, — da
bn) = 26a
dyn == a, — (m— 1) da
The mutual inductance between any two cylinders with radii a,
and a, being M the self-inductance of the solenoid is given by
ped ’
the equation :
P=9 9 == mt
Deg OES as SUA ee mane Nels gaye g(a
Substituting the value of « given by (3) in the equation (2) and
taking provisionally, in order to facilitate the survey of the derivation,
3
only the two first terms of @ with omission of the term ene
i
obtain :
M = 4 a*nta? |Varr— a+ f | oe SS)
In this expression we replace a and A by their above values,
a,, a, — da ete. and expand the terms within the square brackets
according to ascending powers of da. We neglect all terms in which
da occurs to a higher degree than the second, and for the above
mentioned reason we also omit the terms with da resulting from
the expansion of the form under the radical.
Moreover putting Va,+—=r we find for the terms of the
integral (4):
60
Proceedings Royal Acad, Amsterdam. Vol. XIII.
( 920 )
a |
M), = 4nFn*a,* } — a, Al. 5
a ; 2 da
Vo = 42°n?a," i oe ag a, ra 2da da |
25 ; : | : 8 8 8a, {
a, da Ja
Moo 4701 an — —a,-+ da aa ee
2 5 :
a, 4da 4oa
My.3 = 4a*n?a r — aA, ate ee a5 5a,
Sy eal a, da a, 3da da’ |
Mu 3 = 42°n?a,? i aca 1 a, + da+ etry a
2a, da . 2da
Ms.5 = 42°n?a,? \r — —— — a, + 2da - — — a7
7
; ve 970
My) 4= 42°n as —a pe NL: Ae
: ; 8 8 8a,
a, da F a, oda dda”
tie == 40*n* a; ‘ ar as a, + da +- ek Ba, (6)
WM. ‘ 2a, da Tees. a dda Ja. |
— == SS 2da + — — — _—
34 — qe na? ey : ty C 8 8 8a, |
Ha, da Mss a, Sda
May4= 4n'n?a,7 \r — —— — a, + 30a — — —
r 8 8
i a 8da 16da-
M5 = 4a°n'a, — a, I awa ca -
a, da a, ida 96a’
Mo 5 = 4n°n?a; 1 ae ae a,+ da + 3 aa oF
ee 5 \ 2a, da she Sign te a, Oda 4da-
— pe a (HI - udu ==
3.5 rn? ke le z a, a = 8 8 8a,
da, da a, 5da da’
Ma5 == 4n7n*a3 se ae — a, + dda + 3 = 3 +- a
_ 4a,da a, Ada
Ms 5 = 420°n*a, —— — a, + 4da + — — —
r 8 8
ele.
The law of suecession for the numerical coefficients of the terms
within the brackets, in each group with the same factor before the
brackets, is very evident, so that the sum is easily found.
(921 )
After adding and ranging we find:
\ a \
cats ° ° ° 2.4 1
= My, —42%n7 | [a,°--20,°--3a,74 4a," 0a," -+.-.] (r- a,- ) ae
a.da
+ | a,’ +3a,7+ 6a,?+10a,7+...] (w - “) os
( Ju
+ | 3a,?+9a,?+ 18a,?4+30a,*+.. We | +
Ja" |
8a, |
The terms 2 and 3 can be combined into one, namely :
aie eS 4 = = 2 . 3da a, da
[a,* + 3a,* + 6a,° + 10a,? + ..] | da — is -
r
+ | a,’ +-5a,*-+-14a,*+30a,*-+ ...]
The infinite series within the square brackets must be integrated.
We replace a,, a,... etc. by their values, a, — da, a,—2da...
etc. and obtain for instance for the first series:
bo
a, = a,
2 ¢ 2 ° rar
2a,° = 2a,*7 — dada + 2da?
et eS 2 » iy 2) 12
va, —- on, = 12a, da ao l 2da
A 4a,? — 24a, du | 50da" shoe eeia (SS)
ae — O00 e 40a, du a S0da*
MA? = ma,” -— 2m(m—1)a, da + m(m=1)? da?
The numbers in the vertical ranges, figuring as coefficients of
a7, a,da and da? form arithmetical series of respectively — first,
second and third order.
The general expression for the sum of m terms of an arithmetical
series of the 2 order is:
z m(m 1) m(m—1) (m—-2) m(m-—1) (m—2) (m-3)
oa er <2 ge Op 2 We ser siali
m(m—1) ..(m—n)
=e AVE me ee aren esse (CD)
1.2...n+1
wherein ¢, = first term of the series, A,, A,...A, = first terms of
the series of differences, 7 — the order number of the series.
After adding the terms of (8) we thus obtain an expression of
the following form:
Pa,? — Qa,da + Rda?
Wherein P, Q and R are functions of m, which are easily found
60*
by substituting in (9) the values of 4, 4,, 4, ete. obtained from
the consecutive numbers in the vertical ranges of (8).
In order to determine the integral (4) the number of layers m
has to be supposed =o; so it is evident, that in the funetions P,
Q and R, i.e. in the expression (9), we only need to retain the
term with the highest exponent.
This term is:
mi+!
1.2...n+1
ne
We therefore only have to find the order number of each of the series
in the vertical ranges of (8), and the value of the constant difference.
For the term with da* for instance this determination gives:
0
2
2 8 7X, Ne 7) 3
10 6
f20ep 4 ;
a4 6 ee _ 6m eg!
36 20 "1.2:3:4 9 4
Ad
80
2 D1 3
In the same way we find: P= = g— = ;
2
The series in the first term of (7) now becomes, if we omit the
index of «a,
m 2m° m'
S(t a iis ie
a ae Z a
v
Now observing that mda = R,— R; = t, and reducing the fractions
we obtain:
hire 2 2
0 [6m?a? — 8m?at + 3im7t? |
pringing ma? outside the brackets,
mae 6 P t a ae
12 a On
or
?
t
Putting ——eo we finally have:
a
ma , ns
ope aa Saree a|bl co seo tb oy (Il)
Operating in the same way with the two other series in (7) we
find for the coefficients of the terms with da and da’ successively :
( 923 )
heal
— Pa MOE eiaGos\e ve tsws,, etbeeicsi chy)
Hy)
nee Al ney yee nee 5
rt iB Yoel Se INV} | Same ae eco peecee c= ((1!24))
Substituting the values given by (10), (11) and (12) in the equa-
tion (7) and afterwards in (4) we find :
9
2, a
= 82 Bn? 2 2 27 ,
Ly, = — *n*a*m [56—8o + 30°] (: ete ) ie
o
ap. Ho -159 + 60°] (: a *) eee [15—240 + 109°] (13)
5 Siaeaichs Grn ny ts rae: sik, ig
Now expanding and integrating in the above described manner
the other terms of the series «, it appears that each term gives a
contribution to each of the terms figuring in the coéfficients of (18).
In consequence of the particular regularity of these expansions. it
is easy to determine the laws for the succeeding numerical coéffi-
cients of the different series.
In the first term of (13) there appears the series:
al 1 5 35
ee ‘ ( g 64° 1024 1eaed ©
in the second term
Si: (8.44 5-g +7. PL pag fabio Meas
BS 64 1024 | 16384
and in the third term:
i: a (g 48-438. PoE pa ees
: aN'S 64 | 1024 16382"
From the derivation of the fundamental equation (3), that can be
found in the German edition of Maxwe, edited by Werstrnin, it
is evident, that the terms of the series S, are formed by the pro-
ducts of the equal order terms of four different series.
It is therefore very difficult to find back the law of succession in
the above reduced form of these products.
The law of succession is very simple, viz.
(2n—3) (2n —1)
Uy,
TIE aay (2n-+2)
which gives for the general term of the series:
(Qn—3)! ]? 2n—1
Un = | ———— ————-_,
; n! (n—2)! | 24°—4(n-+1)
( 924 )
A® A‘
The terms with _ .. ete. also contribute to each of the
iD eo
coefficients of (13).
These expansions have been executed for all the mentioned terms
|
9 Ail
of (3) except for the terms with — and—~ , which after all would
Lp {Me
be incomplete, these two powers of reappearing in two of the
%
succeeding terms.
After insertion of all these terms and after some simple transforma-
tions, equation (18) can be brought in the following form:
»
‘Le = : anemia" lc, [p, (7) — 0.8488] + C, [¢,(%) + 0.0848] 0 +
»
=i Cres («) t 0.11] 9° je 7 x - S (14)
wherein @— outer radius of coil, insulation included
a7 . 2 t a OWT
Ch = WO ESS alee ON —_ r= Yate
a if
Coa so S605
C, = 15—24u 4+ 100° = number of windings per em.
m = number of layers
/= length of coil
i amt, Ally pple
¢,(«) = 5} — 8 Pa 16 fi — 128 ap.
1 Sy
ve (Gy) ee eT Hee 20 Le —
1 Sn
Pp, (ct) = 30 7 10 Ue a= a4
The constants appearing in formula (14) have the following
meaning :
0.8488 =1—S,
1
0.0848 = — (1 — S,)
1
0.11 = Ss
i =
wherein S,, S,, and S, represent the sums of the above mentioned
series. The first of these constants, which has the greatest influence
on the accuracy of the computed values, is accurate within a few
units of the fifth decimal place.
( 925 )
The accurate determination of these constants is practically equi-
valent with including in the integration a very great number of the
not mentioned terms of (3).
That in formula (14) m represents the jimite number of layers,
Whereas for the integration m is supposed to be djinite, depends
upon the fact, that the self-inductance, for the case the current is
uniformly distributed over the ercss section of the coil, is proportional
to the square of the number of layers.
For moderate values of 9, which quantity in most cases is consi-
derably smaller than 1, the mutual proportions of the coéfficients
C,, C, and C, are very nearly represented by the mutual proportions
of the constants 6, 10 and 15 appearing in these coéfficients. As
the terms with g and g- for long coils are always very small in
comparison with the first term we may put approximately :
6 SSG BOS
2 3 1 3 9 1
o ~
substituting these values in (14), we obtain’:
2 : 5
Ly = — x’n'mia*C, {|¢,(«) — 0.8488] + = [y,(a, + 0.0848] 0 +
+ 5 [yale) + 0.11] 9 |. - (15)
Putting in this formula 9 =O the terms with @ and g? vanish
nde C..— 1.
We then get the formula for the self-induectance of a cylinder or
single layer coil:
Le Ax n* a? (p, (x) — 08488) | se 2 6)
The method of testing the degree of accuracy obtained in the
computation of self-inductaneces by means of the formulae (14) and
(15) is based on the same principle, as used by Rosa in his above
mentioned method.
Rosa‘) begins with the calculation of the self-inductanee of a
cylindrical current sheet, which has the same mean radius and length,
as the solenoid with depth of winding ¢. He takes the total number
l
of windings of this cylinder equal to —, where / isthe common leneth.
; :
Afterwards he considers the solenoid of length /and depth of winding
t as to be formed by one single layer of square conductor, so that
the cross section of this conductor is t><¢ and the total number of
windings is also equal to —
t
1) E. B. Rosa. Bull, of the Bur. of St. IV 369.
D2)
Indicating the self-induetance of the latter by /, and of the former
by L., Rosa caleulates the correction 4, / in order to obtain hey
from /., so that:
Dy = Ly, — A,L.
This correction 4,/ consists of 1 times the difference of the self-
inductance of one winding with square section from that of a winding
on the cylinder, added to the sum of the differences of the mutual
inductances of all the windings. The correction term 4,/ is brought
in the following form :
AL = 4aan(A + B)
wherein 7 in the said number of windings —, @ = the mean radius.
t
A is the part of the correction due to the difference in the self-
inductance, and £ the part due to the differences in the mutual
inductances.
t
Rosa gives two tables, wherein A is given as a function of —
a
and 4 as a function of 7.
The error in Rosa’s method is concealed in this correction term 3,
which, as I shall show in a subsequent communication, is not
only a function of m but also sensibly depends on the value of
so that for this term a table with double entrance would be
a
necessary.
. . . . . t .
I have computed for a few different values of — a table for the
5 a
term 5, by means of which I am able — for these special values of
t
-— to get an idea about the degree of accuracy that can be
(
obtained in calculating self-inductances by the formulae (14) and (15)
Example 1.
/=950 eM. (i De NOG t= 0.4 cM. 4: 10)
calculated :
by formula (14) L, = 70.5976 millihenry
4 . (15) Li, = 105938 %
, by accurate correction method 4, = 70.5992 re
,, by Rosa’s method LE = 70/544 af
by formula (1) of Conun Oro! -
For this example the correction term used by Rosa is: 2 = 0.3440
Whereas the above mentioned table gives: 5 = 0.3247.
S20)
The formula of Coney, as well as Rosa’s method give too small
values for the self-inductance.
An example of the extreme accuracy, obtained with the very
simple formula (16) in computing the self-inductance of a cylindrical
current sheet, as compared with the value calculated by the exact
formula of Lorenz ') with elliptic integrals, may be given here:
Example 2.
/==507 em: ad. em: = i(0)
calculated :
by formula (16) 1, = 4.540489 millihenry.
» Lorenz’s formula Ls, = 4.540486 -s
Physiology. — “On the permeability of red bloodcorpuscles in
physiological conditions, more especially to Alkali and Earth-
alkalimetals’. By Prof. H. J. Hampcrerr and Dr. F. BuBANovic.
Mr. G. Gryxs has published a short article in this paper’), in
which on the ground of some calculations he thinks it desirable to
object to some of the conclusions we drew from our experiments
on the subject mentioned above. (Proceedings of June 25%, 1910).
We feel convineed that his remarks would not have been published,
if he had waited for our more explicit communications on this sub-
ject, in the “Archives Internationales de Physiologie”. As appears
from a note on the first page of our paper we had promised these,
and they indeed appeared shortly after *).
In this treatise a detailed account is given of the experimental
method and moreover by way of example a lengthy report is added
in an appendix, containing full particulars of one of the series of
experiments. In these proceedings it is hardly possible to enter into
details, especially when, as in this case, extensive investigations are
concerned. A detailed description is better in its place in a physio-
logical periodical.
This remark might suffice, but it is perhaps of some use that
those who cannot immediately consult the ‘Archives Internationales”
are made acquainted with the mistake of Dr. Gryns.
1) Bull. of the Bur. of St. V, 41.
2) These Proceedings of October 29, 1910.
3) La perméabilité physiologique des globules rouges, spécialement vis-a-vis des
cations. Archives Internationales de Physiologie. Vol. X. p. 1. Appeared September
24th 1910.
( 928 )
An example taken at random may serve to illustrate this mistake.
We wish to determine the effect of an addition of some water, for instance,
on the interchange of the component parts of blood-corpuscles and serum.
‘For this purpose we took a certain volume of blood. Let us for the reader's
convenience assume that this volume amounted te 100 c.c Let us suppose
these to contain 40 c.c. of red blood-corpuscles, and 60c¢.c. of serum From
these 60 c.c. of serum we take 20 e@e., and dilute them wilh 7!/, ce. of
water, but now we do not add these 27'/g c.c. of fluid to the rest of the blood, but
only 20 e.., so that the volume of the blood becomes 100 c.c. again. Now it
is obvious that it cannot be expected, as Mr. Gryns does, that the blood treated,
will contain the same absolute amount of substances as the original blood, since
serum has been kept back. This Gryns overlooked, and a similar mistake he made
in the calculation of the experiments, in which the serum was made hy perisotonic
by the addition op NaCl.
If Mr. Grynxs, avoiding the mistake made by him, repeats the
calculation, he will no longer arrive at the conclusion that ‘the
mistakes in our analyses are much greater than the differences upon
which our conclusions are based”, nor will these calculations afford
him grounds for opposing our views as to the permeability of
blood-corpuscles.
Physiology. — “A tumour in the pulvinar thalami optici. A con-
tribution to the knowledge of the vision of forms.” By Prof.
C. WINKLER.
(Communicated in the meeting of 28 January 1911).
The ease, which supplied the material for this paper was the
following:
F. t. B, aged 22, who entered the hospital on February 25th 1909, was born
from bealthy parents and did not suffer from any illness before, neither traumata,
nor venereal infection. He partook of alcohol and tobacco in a moderate way.
Since Dec. 19U8 there was a stiffuess of the right leg, followed afterwards by
unsteadiness in the movements of the right hand. The commissure of the lips on
the right side began to drop. By and by the patient became aware of a pecutiar
sensation in the right half of the body, a certain numbness, and he commenced
to stafamer. Ali these symptoms gradually grew worse without any aching of head
or limbs, without dizziness, without disturbances of vision or hearing, as far as
the patient knows. Only his memory was impaired.
During March and April notes have been taken about the case. The patient, a
very intelligent individual, takes an interest in his surroundings and has right
notions as to space and time; the pulse is feeble, 92 per minute, and regular,
( 929 )
Respirations 22 per minute. Nothing anormal in the organs of the thoracal and
ventral region. In the urine neither albumen nor glucose.
Speech is slow, monotonous, stammering and scanned. No disturbances from
aphasia or faults of articulation. The patient is able to read and to understand what
he reads. Writing is bad (2taxy of the right hand). The pressure on the paper is
irregular. The pencil caynot be maintained in the right direction. Still the writing
is not illegible, each letter and each word being taken separately. No vestige of
agraphy. The head, measuring 53 c¢.M. in circumference, nowhere. aches under
pressure.
The sense of smelling is intact. That of hearing is disturbed slightly on both
sides, to the right a whisper is heard at 1 M. distance, to the left at 2M. The sense
of taste is impaired.
The pupils of the eyes, unequal, a lithe more dilated to the right than to
the left, are reacting well on light and in converging. The movements of the
eyes, except for nystagmus, expecially when looking to the right, can be per-
formed completely. The convergeney is not disturbed. The commissure of the lips
to the right is drooping, the orbital fissure on that side is wider than to the left.
On the right half of the face hardly any folds are to be seen. By active movements,
the muscles around the right angle of the mouth are hardly moved at all. The
facial muscles react normally on electric stimuli.
The tongue is put out tremulously, pointing to the right. The patient holds his
head inclined to the right. The right shoulder droops. The right arm is oedema-
tous, without rigidity or hypotony. All active movements can be made, but they
are performed unsteadily. It is impossible to the patient to make both indexes
meet. Unsteadiest of all are the movements of the fingers. Fastening or unfastening
buttons, taking matches from a box ete., — all this is done ina very clumsy way.
The reflex actions in the right arm are exaggerated. When walking, the right
leg is training. To hop on it is impossible. There is neither rigidity nor hypotony.
Paresis and ataxia are more marked in the nether portion of leg and foot than in
their upper region. With his right foot the patient is not able to put ona slipper,
nor to perform the heel-knee test.
To the right the skin-reflexes of abdomen and cremaster are suspended. The
reflexes of the knee and the tendon of Achilles are exaggerated, without cloni,
A stimulus of the foot-sole to the right is answered by flexion of the small toes
and extension of the large one.
Sensibility is disturbed over the whole of the right half of the hody.
The sense of touch is only slightly disturbed. Coarse touches are perceived
everywhere, subtler ones remain sometimes unperceived.
The sense of pain has suffered much more important alteration. To the right
a pin-point is not perceived to be sharp. This hypalgesia passes the diameter of the
body for nearly 1 c.M. The subjective statement of the patient is, that the sensa-
tions of touches and of painful stimuli are entirely different on the right and on
the left. Cold and heat are perceived less clearly on the right than on the left.
What is most disturbed to the right is the deep-seated feeling, and distally
still more than proximally. Passive movements of the fingers and toes are not
perceived at ali. The tactile circles of Weser are much larger on the right than
on the left. The patient localizes badly on the right half of the body.
To the right he is astereognoslic, e. g. a key given in the right hand is called
after long hesitation “a smail hammer”, a matchbox-is called a cork, a ring a
six-penny piece. To the left all these objects are recognized immediately.
( 930 )
The patient himself states that he is able to see well. Yet, if a key is held
up before him, the left eye being closed, whilst the right eye is kept fixed on a
definite point, the object is immediately recognized for what it is, in the left half
of the field of vision, but not in the right half. In the same way, if the right eye
is closed, a key is not recognized in the right half of the field of vision to the lelt,
As there is therefore a presumption of he viopia the patient is examined by the
ophthalmologist (Dr. Scant), who gives the following statement :
Visus 0. D. /e, Visus O. S. ®/g, for both eyes 5/g.
A slight restriction of the field of vision for both eyes, but no hemiopia, not
for moving objects and not for colours. The fundus presents no aberrations.
This difference led to a more thorough examination, and to the making of
different schemes of the fields of vision. The one repreduced here, was taken
on April 20th 1909 by Dr. Scumpr, the exterior circle indicating the field of
vision for movement, the one marked with crossed lines that for blue, and the |
inner circle that for red.
Date 20, 4. 1910.
72
TA
Field of vision for movement, for blue and red on 20. 4. 1910
At the same time however several figures, measuring 2 c.M. in diameter, were
cut out from white cartoon, hearts, circles, diamonds, triangles etc.
Whenever these different figures were introduced from the lefi, into the left
halves of the fields of vision, they were regularly rightly recognized by the patient at
30°—15° from the fixed point.
But if they were presented to vision from the right, in the right halves of the
fields of vision, they never, although the patient saw them approaching, were
rightly recognized by him, before they reached the fixed point, or before they hada
passed the vertical diameter.
The scheme made from this latter experiment, on April 20th 1909, is likewise
reproduced here.
The exterior boundary indicates the field of vision for movements, the intererossed
Jines mark that for blue. Zhe area filled with circles is the field of vision,
within which the shapes of 2 ¢.M. diameter are perceived. It follows
(931 )
Date 20, 4, 1910.
SS
Y
\)
Ss
S SSS S re.
To SS 3
AAS
Ww
WARS
ISS
160
Field of vision for movement, for blue and for shapes of 2 ¢.M. diameter.
The field, within which shapes are recognized, is filled with circles.
from this scheme that only in the left halves of the fields of vision the shapes
are recocnized, not in the right halves.
Gradually the state of the patient grew worse.
Especially the ataxia of the right hand suffered aggravation. With voluntary
movements most violent accessory movements were shown, When in rest, the hand
assumed a peculiar position. The disturbance in the deep-seated feeling aggravated
quickly. The patient was no longer able to localize rightly, his knowledge about the
position of the hand was lost and the astereognosy became complete.
Speech too became more difficult.
Still, neuritis optica was not to be stated, and the visual symptoms remained
stationary, until on May 15th death occurred suddenly.
At the autopsy, in the left half of the brain was found a tumour,
which was yielded in toto to me, thanks to the kindness of Prof. pr
VRIES; On examination it proved to be a glioma. There was made
a series of frontal sections of the brain. These sections, treated partly
with the Weicrrt-Pat method, partly with carmine, gave the following
data as to the extension of the tumour.
Section 1. It strikes the left hemisphere through the proximal region of the
basal ganglia. At the same time it touches the proximal portion of the tumour,
which, being but vaguely defined here, perforates the capsula interna, infiltrating the
lenticular nucleus and the commissura anterior.
Section 2. It strikes the left hemisphere through the middle of the thalamus,
which is enlarged by the tumour, and the right hemisphere through the distal end
of the thalamus. The medial and ventral nuclei of the thalamus are substituted
by the tumour. The regio subthalamica, together wilh the red nucleus and fasciculus
retroflexus has been pushed ventralward. The field of Wernicke and the retrolen-
lieular capsula interna are not touched by the tumor and have been pushed
frontalward and downward.
Section 3. It strikes to the right the distal ending of the pulvinar, The left thala-
mus is enlarged by the tumour in all directions. The tumour has here taken the
place of the pulvinar thalami, destroying at the same time its ventral nuclei
with the radiations of the lemniscus entering these nuclei at their ventral surface,
and the ec. geniculatum internum. ‘
The ec. gen. laterale is found to be remoyed sideward, but otherwise intact.
The cells are arranged in it in the ordinary manner, and the intact radiations of
the triangular field of Wernick (section 2) originate in this intact ganglion (as
may be seen in sections between 2 and 8),
In the retro-lenticular capsula interna however an extensive degeneration of
fibres towards the parietal gyri is found.
The corp. quadr. anticum has been pushed aside, without being destroyed by
the tumour. The tumour pushes aside the radiation from the tractus to this
ganglion, but, as is made evident by sections between 8 and 4 the ec. quadr, anti-
cum is not infiltrated, although a few fibres in its superficial medullar-layer have
degenerated.
Section 4. Ic strikes the left hemisphere a little before the splenium corporis
callosi. The enormous pulvinar, entirely substituted by the tumour, has pushed
aside the splenium and the lateral ventricle without injuring their tissues. The
tumour has grown together with the posterior portion of the Cornu Ammonis, and
is lying therefore, covered by the alveus, within the wall of the ventricle.
Section 5. It strikes the distal end of the tumor. Grown together with the
Cornu Ammonis the tumour compresses the ventricle, without injuring its wall.
Section 6. It strikes the occipital lobe circa 1 ¢.M. distalward from the tumour.
After comparing these different sections, we are justified in assiming
that a tumour, originating in the left pulvinar thalami, growing is
distalward, has compressed the posterior horn of the lateral ventricle,
is destroying frontalward the ventraland medial nuclei of the thalamus,
and is threatening finally the capsula interna, situated more frontally.
The corpus geniculatum laterale and the jibres passing through
the triangular area of Wrwrvsicxn, however are almost completely
intact, as is likewise the corp. quadrigeminum anticum.
In the retro-lenticular region of the capsula interna there are
degenerate fibres, part of which pass thence into the strata sagittalia,
whilst another part goes directly in the corona radiata of the lower
parietal brain, towards the gyrus supra-marginalis (fig. 8, 4, 5).
In the stratum sagittale internum a mass of degenerate fibres is
lying laterally from the ventricle and passing gradually through the
stratum sagittale externum they enter into the medullary cones. of
the gyrus angularis and of the basal occipital convolutions.
Remarkable is the aspeet of the medullary cones (see section 6)
of the circonvolutions around the fissura calearina, They appear as
solid black fascicles.
( 933 )
Nevertheless in both, as well in that of the gyrus cuneus as in
that of the gyrus lingualis, there is a stria of degeneration.
In the medullary cone of the g. cuneus this stria is lying dorsally,
in the direction of the dorsal portion of the cuneus. The part of the
cone situated beneath the cortex in the f. calcarina, is wholly
free from degeneration.
In the medullary cone of the g. lingualis the degenerate stria is
situated ventrally, directed towards its ventral portion and connected
with the degenerate layer of the medullary cones of the occipital
gyri. In the g. lingualis too, there is no degeneration in that part
of the medullary conus, confining the cortex in the f. calearina.
Both lips of this fissura, are in Wericert-PaL preparations surrounded
by black coloured medullary cones.
The tumour found in the left thalamus may aid us to understand
the general view of the symptoms of disease.
The present state of our knowledge enables us to conclude that
the hypalgesy of the right half of the body, the loss of the deep-
seated feeling and the false localisation on that side, the accessory move-
ments and the ataxia of the right hand, and likewise the astereoqnosy
im the vight hand ave dependent on the destruction of the veutral
and medial nuclei of the thalamus.
The growing weakness of the right half of the body, the mono-
fonous, stammering speech present indications of the tumour develop-
ing frontalward, and perforating the capsula interna.
The destruction of the left corpus geniculatum internum may
perhaps be held responsible for the disturbance of hearing on both sides.
Most remarkable however is the disturbance of vision in the patient,
as the fundus does not present any abnormal condition. A superficial
examination le to a presumption of hemiopia, but after a more careful
investigation it beeame evident that, apart from a slight restriction
to the right of both fields of vision, the patient was able to perceive
movement and colour in both halves of the field of vision. On the
contrary, shapes are not perceived at all in the right halves of the
field of vision. They are recognised however in the point of fixation
and in the left halves of the fields of vision until far towards the
periphery.
It ensues that these disturbances are dependent on «a tumour,
originating in the left pulvinar, which has destroyed this ganglion
together with its medial and ventral nuclei, whilst the corpus geni-
culatuin, laterale, Wwryicky’s field and the corpus quadrigeminum
anticum were left intact by it.
¢
The shape of an object is recognized best by a normal persons, near
and in the point of fixation. Small shapes, comprising many details,
the letters and words we read, are even exclusively perceived there
and consequently seen with the fovea centralis. Everybody however
may ascertain for himself that shapes, measuring 2 ¢.m. in diameter,
will be recognized temporalward unto 40° in the periphery, if they
are presented at a distance, equal to the distance of our point of
distinet vision.
When the light is bad, the recognizing of shapes in the periphery
decreases very quickly in normal persons. Such is likewise the case,
when through disease of the N. opticus, there is an important restriction
of the field of vision.
Our patient, presenting no abnormal fundus, no distur-
bance in the perception of light, no blindness for letters or words
(no alexia), no optical aphasy, and no other impediment for locali-
zing with the eyes, than nystagmus when the eyes are fixed
to the right, does not recognize shapes to the right, however large
these shapes may be. This disturbance which incommodes him only
very little, is first brought to his knowledge by the doctor. Then
he ascertains its existence from the beginning of his disease.
In order to understand this disturbance, it will be necessary to
take notice of the studies on alexia, made by Nissi von MAyENDORE® *),
As the point of departure for his researches this investigator
took two facts.
1. Letters and words are recognized only in the neighbourhood
of the fovea centralis.
2. Whenever bilateral occipital foci (tumour, softening) determine
bilateral hemiopia, there remains a central field of vision, by means
of which the patient is able to recognise small forms and colours
and to read. On the basis of anatomical arguments, he then proceeds
to construct these two propositions :
1. the fovea centralis, projected on the cortex by a_ special
bundle of fibres in the dorso-lateral strata sagittalia a, is localized in
a separate cortical area. ;
2. The destruction of these fovea-fibres or of this cortical area
will determine alexia (blindness for letters and writing) either sub-
cortical or cortical,
The first part of this argumentation is not new, but the second
part to a certain extent is.
1) Erwin Niesst von Mayenvorrr, Das Rindencentrum der optischen Wortbiider
Arch. fiir Psychiatrie. Bd. 43 8. 633. 1908 and other communications e. g.
Ueber eine directe Leilung etc, Wien KI, Wochenschrift Noy. 1906.
All independent investigators agree on this point, that the fovea
eentralis must be represented in a special manner on the cortex.
They are torced to acknowledge this by the fact, that the hemianopsy
determined by occipital foci is always incomplete, 1. e. there is. still
a remnant of the field of vision that has not become blind, and to
this remnant belongs the fovea.
Therefore this latter must be represented in a particular way in
the cortex.
But there is a great divergence of opinions about the manner in
which this particular representation is effected.
Some investigators claim for the fovea a separate cortical area
(situated eg. at the bottom of the fissura calearina, HENscHEN, SACHS,
WILBRANDT).
Others believe the fovea centralis to be localized in a diffuse
manner in a very extensive cortical area (to which should belong
not only the environs of the fissura calearina, but also at least the
occipital gyri, von Monanow).
This divergence of opinions may easily be understood. After it has
been proved (Forster, among others’ that the patient with bilateral
hemianopsia still possesses a central remnant of the field of vision,
there remain only two possibilities.
Either in these cases, there remains intact on both sides a cortical
area of the fovea, — or the diffuse dispersing of the fibres con-
ducting the fovea-impulses towards an extensive optical cortical field,
allows the possibility that even after a relative extensive destruction
of cortex and fibres, a certain number of these fibres may have
been left intact, and consequently central vision unimpaired.
As however, until now, there were known no well ascertained cases
of central hemianoptic scotoma, dependent on accurately demonstrated
occipital foci, the partisans of a diffuse localization of the fibres of
the fovea have a decided advantage over those, who defend the
especial cortex-area of the fovea.
The second, new proposition of Ninssi, interferes in a peculiar
way in this dispute.
The field of the fovea of Nirssi. is no longer the fovea-field in the
fiss. calcarina, as it has been conceived by H&nscnurn among others.
The fovea-fascicle of Nresst irradiates into the dorso-lateral mass of
the strata sagittalia, towards the basal occipital gyri and even in the
cuneus, not into the calcarina-field but around it.
This fascicle being interrupted (e.g. by a softering focus in the
eg. angularis or by the destruction of its cortical field), the ensuing
symptom will be, no longer a central hemianoptie scotoma, but,
61
Proceedings Royal Acad. Amsterdam. Vol. XIII
if the interruption takes place to the left, the non-recognizing of
those forms perceived with both fovea, which are connected with
the left fascicle.
As the left hemisphere serves especially to the recognition of
words that are heard and to speech, subcortical or cortical loss of
recognition of the forms used for speech will be the consequence,
or in other terms, subcortical or cortical alexia will originate.
In Niesst’s conception the calearina-region has become a pure
optic zone, the light-perceiving zone of the cortex. Here he agrees
with Campsett, BropMAaNN and others. The surrounding con-
volutions form the fovea-area. They serve in connection with the
optic zone to recognize shapes.
In my opinion this really most ingenious conception of Nrrsst
von Mayenporrr is not affected at all by the dispute, whether or
not there exists a special fovea-fascicle situated within the strata
sagittalia. Bat the case described in the foregoing concerns the greater
question put forward by Niessn, if there exists a loss of vision of
forms, without a sufficient loss of light-perception.
Shapes are recognized not only with the eye, but also with the
hand. More than once there have been stated cases of so called
astereognosis, the impossibility to recognize shapes with the hand,
though the tactile perception has suffered relatively only a slight
disturbance.
Foci within the inferior parietal lobe, (WernickE), in the ventral
thalamus-nucleus or in its radiation towards this parietal lobe, deter-
mine the loss of recognition of forms, without the loss of tactile
pereeption.
In the described case too there was astereognosis of the right
hand, corresponding to the destruction of the ventro-medial thalamus-
nuclei and to the degeneration of their radiation towards the parietal
gyi of the left brain.
It lies near to seek for an analogy between the astereognosis and
the above described disturbance in recognizing optical shapes.
If in the ventral nuclei of the thalamus, impulses from the general
sensibility (the deep-seated parts of the body) and from the tactile
region meet, if there a new entity is composed of those different
impulses, which after further activity of the cortex, enters into con-
sciousness as a_ tactile shape-image, we may assume a similar pro-
ceeding to take place for the optical impulses.
For into the pulvinar radiates a fascicle from the tractus opticus.
Optical impulses are brought into immediate connection with the
( 937 )
kinaesthetic impulses, which are elaborated in the ventral unclei. The
cortical radiation from the posterior regions of the thalamus however
lies more backward, it is directed towards the gyrus angularis,
the basal occipital convolutions and the cuneus. In this radiation
an important degree of degeneration could be demonstrated, but the
degenerated fibres do not penetrate into the borders the convolutions,
surrounding the fissura calearina. They are found in the field of the
fovea, indicated by Ninsst.
Consequently, although still sufficient optical impulses join the
cortex along the corpus geniculatum laterale and the cortical radiation
originating from it, yet the cortex, receiving no communication as
to the result of the elaboration of several other impulses that should
have been prepared in the thalamus, no longer recognizes shapes
in the crossed fields of vision.
This analogy holds good only, in as far as the optical sense
together with the sense of touch and the kinaesthesia renders the
conception of shapes possible.
The eye may also, independently of the sense of touch, recog-
nize shapes, perceive a third dimension ete.
Some time ago, the studies about disturbances in the pereeption
of a third-dimension (Tiefen-Wahrnehmung), which are only sparsely
seattered in literature, have been augmented with one by Dr. van
VarkenpurG. bilateral foci in the gyrus angularis had determined
this disturbance, together with other symptoms, among which alexia.
Although the perception of a third dimension has some relation
with the recognizing of shapes in two dimensions, vet it is distin-
guished from it, as it is likewise from stereoscopic vision.
After the demonstration of vay VaLkenpure I think it needless to
argue this point,
Necessary it is however to recall to mind an interchange of thought,
that occurred about this subject between Dr. Nissi and Dr. van
VALKENBURG ') viz. whether the dorso-lateral region of the strata
sagittalia may contain a special fascicle of fovea-fibre. I have stated
already that in my opinion, this is not the principal question. The
chief point appears to me the question, whether there may be made
a division between a light-perceiving field around the f. calearina and
another field enclosing the former, within which, occasionally with
the aid of the first field, shapes are recognized.
1) CG. T. van Vatxensure. Zur Kenntnis der gestéhrten Tiefen-Wahrnehmung. Deul-
sche Ztschr. fiir Nervenh. Bd. 34. S. 322.
NiessL von Mayenporrr. Einige Bemerkungen zu dem Aufsatze des Herrn Valken-
burg. lbidem Bd. 35. S. 165.
Van VatkensurG. Kurze Erwiderung auf die Bemerkungen e‘c. Ibidem Bd. 35, S. 472.
61%
( 938 )
If | am right in my conception, that the degenerated fibres in this
case (the borders of the calearina are intact) are dependent on the
destruction of the thalamus and not on the pressure of the enormous
tumour on the dorso-lateral portion of the strata sagittalia, there are
at any rate strong grounds in favour of it. For the patient showed
no symptoms of alexia and there is a continous connection between
the tumour in the thalamus and the degenerations having their
origin there.
But if this conception be true, this case would apparently aid to
support the opinion that in Ninssi’s fovea-zone, there entered likewise
fibres from the periphery of the retina. For in the case, as described
above, the shapes were recognized in the fovea.
If the conditions presented in this case, allow the conclusions
that whilst the perception of light was retained, shapes could not be
recognized hemianoptically, then if must be conceded likewise that
Nirssn’s fovea-zone contributes also to the vision of shapes with the
periphery of the retina.
And this being so, it must be conceded further, that the light-
impulses in themselves are insuflicient for the recognizing of shapes,
that it is only in their connection with other impulses, a connection
prepared within the thalamus, that they become able to communicate
to definite portions of the cortex the data, enabling this latter to
recognize shapes.
LEGENDA OF FIGURES:
a.l.=ansa lenticularis. AM=cornu Ammonis. ag= Aquaeductus Sylvil. AVG= gyrus
angularis. br.c.=bracchium conjunctivum cerebelli. c.=sulcus centralis. c.@.=com-
missura anterior. C. A.=gyrus centralis anterior. c.a./.—columna ascendens fornicis.
cale.=fissura calcarina. ¢c.c.=corpus callosum. c. ext.=capsula externa. c. extr.=cap-
sula extrema. c.g.e. of c.g./.=corpus geniculatum externum sive laterale. c. 7.=cap-
sula interna. c/.—claustruim. c.m.=sulcus calloso-marginalis. €.M.=gyrus calloso-
marginalis. C.P.=gyrus centralis posterior. ¢.g.a.=corpus quadrigeminum anticum.
C.R.=corona radiata. C. U.N.=gyrus cuneus. f.=fornix. 7; =sulcus frontalis
primus. Fi=gyrus frontalis superior. f,—=sulcus frontalis secundus. Fil= gyrus
frontalis secundus. Fii=gyrus frontalis inferior. f.0.—fasciculus fronto-occipitalis.
f.r.= fasciculus retroflexus. FUS = gyrus fusiformis. #=sulcus Hippocampi. H= gyrus
Hippocampi. hab. =habenula. /VS.=insula Revi. .p.=sulcus interparietalis. 2=lem-
niscus L1= globus pallidus nuclei lentiformis. Ly, £3; = putamen nuclei lentiformis. L/=
gyrus Lingualis. 7.c.=nucleus caudatus. 7. ant=nucleus anterior thalami. 72./.=
nucleus lentiformis. 7. Zat.=nucleus lateralis thalami. 7m. med.—nucleus medialis
thalami. n.ventr.=nucleus ventralis thalami. 7. ret. nucleus reticularis (Gitter-
schicht) thalami. 7.r.=nucleus ruber. 0; =sulcus occipitalis primus. O; = gyrus
occipitalis primus. 0,=sulcus occipitalis secundus. Om = gyrus occipitalis secundus,
o,=sulcus occipitalis tertius. Omu1= gyrus occipitalis tertius. 0.p.—sulcus occipito-
parietalis. of= sulcus occipito-temporalis. O7= gyrus occipito-temporalis. Pi = gyrus
parietalis superior. PAR =gyrus paracentralis. p.c. sulcus post-centralis. ~p.P.=
pes pedunculi p~.o.=sulcus parieto-occipitalis. ~.r.=sulcus praecentralis, PRC.=
gyrus praecuneus. p.s.—=sulcus parietalis superior. S=fissura Sylvii. S.W. = gyrus
( 939 )
supramarginalis. s.7.=substantia nigra. s.o/f./.=stria olfactoria lateralis. s.s..=
stratum sagittale internum. s.s.e.—= stratum sagittale externum. 4 = sulcus temporalis
superior. 71= gyrus temporalis superior. f = sulcus temporalis secundus. 711 = gyrus
temporalis secundus. #=sulcus temporalis.tertius. 7im1= gyrus temporalis tertius.
tap.=tapetum. ¢r.o.=tractus opticus V =ventriculis lateralis. v. d’As.= fasciculus
Vicq-@ Asyr. W = Wernicke’s field.
Physics. — “The Rectilinear Diameter for Oxygen”. By K. Marutss
and H. Kamertmcn Onnes. Communication No. 117 from the
Physical Laboratory of Leiden.
(Communicated in the meeting of June 25, 1810 and January 28, 1911) !).
§ 1. Introduction. As far back as Dec. 1894 the comparison of
the equation of state for the permanent gases (particularly that for
hydrogen) with the equation for ordinary normal substances was
mentioned in Comm. N°. 14 dealing with the Leiden cryogenic Labora-
tory as being one of the first objects for which efforts were made
to develop the methods now used for obtaining accurate measurements
at very low temperatures. While the law of corresponding states was
assumed fo be approximately correct for the group of substances of
very low critical temperature as well as for the other normal substances,
there were still reasons for suspecting that their reduced equations
of state would show deviations on comparison with those of other
substances greater than are found between various groups of ordinary
normal substances. In fact, the reduced empirical equation of state for
ordinary bodies differs considerably from the original reduced equation
of vAN beR Waats; nor does this difference disappear when the
equation is modified by making a caleulation of the influence on the
kinetic pressure of the finite dimensions of the molecules stricter than
that developed by ascribing a constant value to b>. At that time the
hope could be cherished that substances such as oxygen, nitrogen,
and hydrogen would, on account of the simpler constitution of their
molecules, show a better correspondence with the assumptions upon
which van perk Waats based his calculations, and that their reduced
equations would approximate to the theoretical van per Waats
equation, showing at the same time deviations from the reduced
equations for the other substances.
Operations intended to throw light upon this subject made but slow
progress *). Cryostats had to be constructed that put a range of
1) An excerpt from this paper appeared in the C.R. July and Aug. 1910. The
Académie des Sciences at Paris has shown its greal interest in the study of the
rectilinear diameter of liquids which exist at very low temperatures only, in granting
one of us a subvention from the Bonaparte Fund so as to be able to come to
Leiden. It is an agreeable duty to record our cordial thanks for tus.
2) See introduction to Comm. No. 97@ (March 1907).
( 940 )
sufficiently accurate temperatures at our disposal: the liquefaction
of hydrogen soon appeared upon the programme: the piezometry
and thermometry of low temperatures had to be studied. In the
meantime were discovered the monatomic gases whose molecules
probably answer best the assumptions made by van per WaAAts, and
helium at onee usurped the place originally set apart for hydrogen.
And now helium itself has been ‘liquefied, but the number of
isotherms of different gases that have been determined is small while
the region covered by them is narrow, and although the problem
that is being worked out at Leiden has undergone important exten-
sions, it still retains the same character as before.
Helium is now the substance to which one would @ priori ascribe
an equation of state most resembling the van prrR Waats equation.
In this connection it remains to be shown how, from the surfaces which
represent the reduced equations of state for ordinary normal sub-
stances (passing over first those for oxygen, nitrogen, etc. argon,
then those for neon and hydrogen) that for helium may be derived
by continual deformation ; to this one would like to ascribe a limiting
form.
Comms. No. 71 (June 1901) and 74 contain a reduced equation
of state obtained by combining the different portions given by various
measurements with hydrogen, oxygen, carbon dioxide, ether and
isopentane, each for the region of reduced’ temperature which
corresponds with the ordinary temperature for that particular
substance. In the Leiden researches this mean equation of state is
regarded as an envelope which is in contact with each of the special
surfaces of state in that region to which it bas contributed to form
the mean equation, while the special reduced surfaces for the
various substances separate from each other and from the enveloping
surface in the other regions, the helium surface in this respect
exhibiting the greatest deviations. In fact, the special reduced equation
for hydrogen [VI], H,, Comm. No. 109a § 7 equation (16), March
1909] differs markedly from the mean (VII, 1, Suppl. No. 19, p. 18),
and measurements already made with helium (cf. Comm. No. 108,
Aug. 1908) confirm the fact that its equation of state differs from
that for hydrogen in the same way as this has been found to differ
from oxygen and nitrogen.
The deformation of the surface representing the reduced equation
of state is accompanied by a deformation of all corresponding lines
on it, thus occasioning a change in the reduced values of all magni-
tudes deduced from the equation. This point will be treated in
greater detail in an article by H, Kamertincn Onnns and W. H. Kersom
el ee ee ee
( 941 )
on the equation of state and its graphical treatment in the Eney-
klopadie der Mathematischen Wissenschaften.
One of the most important of these reduced magnitudes seems to
be the rectilinear diameter. In 1899?) it was shown that the law:
of corresponding states was not true as regards the diameter for
substances as a whole. On the supposition that the diameter is also
a straight line for substances of very low critical temperature, the
measurements made by Duwar and by Wrosriewski show that for
these substances the reduced slope differs greatly from that for ordi-
nary normal substances. This result led to the expectation that the
investigation of the diameter would reveal a characteristic feature
of the whole representation of the differences between the equations
of state for substances of low critical temperature and those for
ordinary normal substances, and this the more so as VAN DER WAALS’
recent researches upon molecular conglomerations in the liquid state
have brought the rectilinear diameter to the front as a means of
determining the law governing such conglomerations.
In an investigation of the diameter of substances of low eritical
temperature the first question encountered is the following. It has
been shown that for ordinary normal substances the diameter is
straight to a high degree of approximation: is this also the case for
substances of low critical temperature? Does the deformation of the
reduced surface, while oceasioning a change in the orientation of the
diameter, leave unaltered its rectilinear nature as ought to be the
case if this straightness were’ intimately connected with the innate
characteristics of the liquid state? This is the fundamental problem
that we have attacked, and it is answered in the affirmative by the
measurements on oxygen which we publish in the present paper *).
Oxygen’) was very suitable for this first investigation as it remains
liquid down to a very low reduced temperature (0.30), and with
the cryostat and the thermometric apparatus that had been prepared
for the investigation of the isotherms we have mentioned, we were
able to trace the diameter from the critical point down to — 217°C.
(reduced temp. 0.36).
If one were to leave neon and helium out of the question as
affording too many difficulties for an investigation of this kind, then
liquid densities at still lower temperatures could be obtained with
hydrogen only. As yet, however, a cryostat for hydrogen is wanting
1) HE. Maraias. Liege Mém. Soe. Roy des Se. 2 (1899).
2) The results were already given in the excerpt published in G.R. July-Aug. 1910.
3) Measurements of the density of liquid oxygen were announced Comm, N°, 95
(1906) pg. 28 note |.
( 942 )
for temperatures between its boiling point and its critical point, so
that measurements for the most important portion of the diameter
viz. that part lying between the boiling point and the critical point,
are not yet possible, and only that part of the diameter lying below
the boiling point, which» we may term the produced diameter, is
available for measurement.
A final reason for the use of oxygen is that it can be easily
prepared in a perfectly pure condition, This was done by heating
potassium permanganate contained in tubes forming part of an
apparatus made completely from glass. The oxygen liquefied in
another part of the apparatus that was immersed in liquid air, and
was then distilled from this apparatus into a cylindrical reservoir
(see § 4) that was in its turn cooled in liquid air. The quantity of
liquid condensed in this reservoir was so regulated that when the
ordinary temperature ‘was reached again, the safe pressure allowed
by the construction of this copper cylinder was not exceeded.
§ 2. First Method. Densimeter. We deduced the constants for the
diameter from measurements of the densities of the liquid and of
the vapour at a series of different temperatures. At every density
determination for both liquid and vapour the phase whose density
was being determined was kept in equilibrium with a small quantity
of the coexisting phase.
Fig. 1 Pl. IL represents an apparatus with which the diameter
can be directly determined. Two equal reservoirs A and 6 are
connected by means of a graduated capillary c; the upper reservoir
ends in a narrow capillary coupled to a tap 7. The internal volume
of the apparatus as far as one of the divisions d is twice the volume of the
lower reservoir as far as one of the divisions on the capillary c.
The dilatometer is now filled so that at the lowest temperature
employed, the liquid meniscus stands at the central mark: the tem-
perature of the apparatus is then raised and each time this is done
so much of the vapour is allowed to escape through the tap / that
the liquid meniscus always touches the central line. The quantity
of oxygen contained in the apparatus at the lowest temperature and
the quantities which are successively allowed to escape on proceding
to other temperatures are measured, and corrections are applied for
the narrow capillary e, for the difference between the nominally
equal volumes V4 and J’, of the two portions A and / and also
for the difference between the liquid level and the central mark,
and then the data for the diameter are at once deduced from the
equation V A Otig -t Vp Qvap = V4 (lig Qrap Nis where V4 is known,
: ( 943 )
We have not yet used this apparatus, but as we have already
mentioned we made use of the less direct method of determining
Olig ANd Ora, Separatedly for the same temperature, sometimes adding
determinations of ihe difference @/ig — Qva,.
To determine Qi, and Qra, a glass reservoir of known volume is
filled with the phase to be investigated, while a small quantity of
the coexisting phase is allowed to be present. This reservoir is joined
to a narrow. glass capillary, which allows it to be immersed in a
bath of liquefied gas in one of the cryostats of the cryogenic laboratory.
The glass capillary is continued by a narrow steel capillary tbat
can be closed by a tap. Since the measurement of the quantities of
eas filling the densimeter is, as will be seen in § 3, made in a
volumenometer, if would seem desirable to make use of different
reservoirs if the densities of the liquid and vapour are to be determined
with the same degree of accuracy; but for the purpose of our
measurements this was not necessary. To determine a point on the
diameter it is not necessary to obtain such a high percentage accuracy
in the density of the vapour as in that of the liquid; it is sufficient
if the quantity filling the reservoir used for both determinations is
known with the same absolute accuracy in each case. Hence the
same reservoir may be used for determining Qiiy and Qrap.
As the determination of the vapour density necessitates an accurate
knowledge of the volume of liquid that is left in equilibrium with
the vapour, the reservoir of the densimeter terminates at its lower
extremity im a graduated appendix a. Unfortunately, the capillary
chosen for this appendix was so narrow that in the course of the
measurements if was necessary to take the level of the liquid in the
conical portion of the capillary above the graduation. In these cir-
cumstances it was rather difficult to obtain this correction ').
The shape of the reservoir was so chosen that the method of
constant mass as well as that of constant volume could be employed.
With this end in view the reservoir consisted in part of a graduated
stem d.—d.; thus the apparatus formed a dilatometer provided with
a very narrow capillary dy and a tap /,, as well as an appendix
d,. While the tap /, remains closed, the liquid meniscus that at the
1) This was done in the following way: Copies were constructed from pieces
of the same kind of glass to exactly the same external dimensions. and of such
internal dimensions as to be optically identical. These copies were then subjected
to successive grindings and the internal dimensions were taken after each grinding;
the volumes were then determined by integration. We gratefully acknowledge our
indebtedness to Mr. G. Hotsr for the care which he devoted to this part of the
jnvesligation.
( 944 )
first. temperature stood at the highest mark on the stem which we
may call a, sinks as soon as we proceed to lower temperatures.
The levels of the liquid 9,,%,.. - a, corresponding with the
constantly decreasing temperatures 7’, 7,... 7), are read with a
cathetometer microscope until at last the level of the liquid sinks
beneath the stem ,—-d, (Pl. Il. fig. 2). To turn these measurements
to the best advantage, the dimensions of the appendix d, must be
so calenlated that when the tap is closed for determinations of the
densities of the vapour at the temperatures 7, 7’,, 7... 7), readings
of the level §,,6,6,...6) in the capillary of the appendix can be
made. In that case one can calculate directly the corrections that
must be applied to the rough values Of Gigs Qtig, +++ Olign ANA Qvap,
Ovgps ++ Qravn Which are obtained by neglecting the correction for
the small quantity of the coexisting phase, whereas otherwise these
corrections would have to be determined by successive approximations ').
The condition essential to the successful application of the simple
method viz. that accurate equality may be realised between the
cryostat temperatures at which the liquid and the vapour densities
are determined, was fulfilled in our experiments, and so there was
every reason to make use of this circumstance in our application
of the method of constant mass to temperatures between 7’, and 7%,
As determinations of mass in the case of a permanent gas necessitate
rather difficult measurements, it can be seen that the number of
separate mass determinations necessary when the constant volume
method (that in which the dilatometer from a mark on the appendix
to the uppermost mark on the stem functions as a densimeter) is
exclusively used, ought to be limited to as narrow a temperature
range as possible. For this reason the dilatometrie method (of constant
mass) is combined with the densimetric (or pyknometric) method of
constant volume: the former method as indicated above gives the
data neccesary for a series of intermediate temperatures, while the
latter affords, as it were, the standard points in the range of tempe-
ratures to be traversed between which intermediate points are inserted
to correspond with temperatures occurring between two standard points.
For oxygen, and this is in general the case with the permanent
eases, neither the constant mass method nor the constant volume
method can be rigorously applied over the whole range of
temperatures. To traverse the various regions of temperature
it is sometimes necessary to change from one temperature bath
to another and this can only happen by exposing the apparatus
') KK. Marnias, Remarques sur le théoreme des états correspondants. Ann. de
Toulouse 1891,
a = >
’
Po)
( 945 )
to the ordinary temperature in between. To do this it is necessary
to allow the gas to escape from the dilatometer and then allow
it to return when the second low temperature has been
established. For measurements with oxygen the lowest temperatures
are given by a bath of lhquid oxygen, from — 217°C. to —1838°C.,
temperatures between — 183°C. and -— 164°C. are obtained with
a bath of liquid methane, and temperatures between — 164°C. and
— 120°C. with a bath of liquid ethylene. In this way one must
begin with a new quantity of material at least three times. Hence
some standard points on the temperature scale are given by the
nature of the bath itself.
On the other hand a change of apparatus on proceeding from one
region of temperature to another would be a decided advantage from
the point of view of obtaining greater accuracy. The expansibility
of the liquid and the density of the vapour increase rapidly as the
critical temperature is approached: it is clear that if one did uot
wish to be confined to too small an interval in using the same
dilatometer over this region, one would choose varying diameters for
the stem and for the appendix. For this reason we constructed a
series of dilatometers with different stems and different appendices
calculated for a series of temperature intervals. Dilatometers that
had to be used at temperatures nearer the critical had appendices
and stems of greater diameter than the others. Furthermore, by
constructing our dilatometers of two parts united by a graduated
capillary we tried fo provide ourselves with as many controls as
possible, for by this device we should be able to check direct
measurements made with each of the individual apparatus with one
or more of the measurements that were made with another.
In our first experiments we avoided the complications which we
have just described and which are encountered as soon as one
attempts to obtain for all the data for the diameter the greatest
accuracy possible considering the constancy of the eryostat tempera-
tures and the degree of accuracy with which these can be measured.
For this reason we made all our measurements both of vapour den-
sity and of liquid density with the same dilatometer, whether they
were at very low temperature or in the neighbourhood of the
critical. Hence this dilatometer was so constructed that it could
withstand the critical pressure. The great advantage in using a single
dilatometer for all the determinations Jay in the facet that as soon as
if was in its place in the eryostat, one had only to pour in the
various liqnefied gases necessary for the different baths to be able
to traverse the whole range of temperature, and that without having
( 946 )
fo alter the measuring apparatus in’ any way during the whole
series of determinations. It was also of the highest importance
that the densities necessary for the calculation of the diameter
should) be obtained with the same aceuracy over their whole
course, while, on the one hand, the largest quantity of gas which
we could use for each measurement was limited by the dimensions
of the volumenometer, and on the other hand, the accuracy of the
measurements at the highest temperature was limited by the degree
of constaney of the temperature itself. Moreover, there was no
necessity for obtaining a greater degree of accuracy for individual
points than that which is possible by this method and whieh may
be represented by a unit in the third decimal place. This accuracy
is sufficient to determine if the diaméter for oxygen is to be consi-
(lered as straight, and to deduce its slope with the same accuracy as
that with which it has been determined for other substances. In any
case this first step was desirable in order that data might be obtained
to serve for the calculation of the other apparatus mentioned, and to
be useful in leading to a greater degree of accuracy. For the degree
of accuracy desired it was seen that it was not necessary to determine
vapour densities at the lowest temperatures, for it may be assumed
that these densities can be calculated with sufficient accuracy.
The dilatometer is seen in position in the cryostat Cr in the
diagrammatic plan shown in Plate I, its exact dimensions are given
on Plate Il, tig. 2. The method of joining the glass capillary d, to
the steel capillary d, of about 0.6 mm. diameter is deseribed in
Comm. N°. 69 (April 1901) PI. II, fig. 4. The piece dy, is soldered
to the glass in the manner described in Comm. N°. 27 (June 1896);
its end surface is ground perpendicular to the stem; instead of a
leather ring steeped in wax a fibre ring was used as packing. This
connection as well as all other metal connections and taps are kept
a method introduced in Comm.
N°. 946, June 1905; this is done by means of a tube attached at
under test by immersion in oil
a to the cover of the cryostat in which the dilatometer is placed
(see PIT tic. 2 and? RIE 1);
§ 3. Method Il. Volumenometer. The mass of the gas was
determined volumenometrically. We used the accurate volumeno-
meter described in Comm. N°. 84 (Mareh °03). Since then it has
undergone some modifications for experiments by KaAMERLINGH ONNES
and pe Haas on the compressibility of hydrogen vapour at and
beneath its boiling point, the results of which will soon be published
The reservoir for the preparation of mixtures (Comm. N°. 84, PI. IL,
( 947 )
fie. 2) which may be seen in use in the apparatus used for the
experiments of Comm. N°. 85 (Jan. ‘O4) and N°. 92 (Sept. ‘04) was
needed neither for our present experiments nor for those on the
compressibility of hydrogen vapour. The reservoir /” (/" of N°. 84,
Pl. Il) has a separate mercury holder @, (PI. I) and the capillary
connecting this reservoir with the volumenometer is so constructed
that the gas contained in it may be driven completely out by the
mercury. A second tap 4, was put in the fork of the tube conneet-
ing the volumenometer with the reservoir /”; when gas has been
admitted into the volumenometer from the reservoir /” the mercury
is allowed to rise above the tap 4, of the reservoir /#” and in the
volumenometric determinations the volume of the mercury that has
risen in £,—k%, is allowed for by reading the position of the mercury
from the graduations of the calibrated capillary.
The dead space consists of the portion of the volumenometer that
projects above the level (5 in Pl. I) of the liquid in the bath in
which it is placed, and of the spaces between the volumenometer
and the taps of the apparatus that are connected with it (for instance,
hk, and &, Pl. TY) (and usually too, the dilatometer containing that
portion of the gas that remained after the greater part had been
transferred to the volumenometer), but the great advantage of con-
structing the reservoir /” in the above way lay in the fact that in
the calculation of the masses that are measured, this dead space
oceurs only at low pressures, so that if is not necessary to determine
its temperature so accurately. In fact, nearly all the gas to be
measured can be transferred to the reservoir /” which is evacuated
beforehand and then filled with mereury, and if the volumenometer
is used as if it were a pump there remains to be measured in the
dead space only gas that is at a very low pressure. Then, keeping
i, closed, the volumenometer is evacuated through 4, and 4,,, and
the gas that has been stored in the reservoir /” is transferred to it;
this large quantity is then measured at a. temperature that is known
with great accuracy.
The connections between the manometer tube J/ and the large
reservoir & in which a pressure is sustained equal to, or if one: so
desires, slightly different from: atmospheric had also undérgone some
modification for the research on hydrogen vapour compressibilities.
Amongst other alterations we may mention that the connections
which are to withstand a vacuum are either ground or fused together
so that if is possible to measure volumes over the whole volumeno-
meter at all pressures between O and somewhat more than one at-
mosphere. Moreover, a connection may now be made between the
948
lipper portion of the manometer tube and the tube of the volumeno-
meter, By this means control measurements are possible when the
pressure is the same (and in particular when it is zero) above the
mercury in the two portions of the apparatus, which then form two
communicating vessels for the mercury; in that case, apart from
other corrections, the mercury menisci must stand at the same height.
Another control consists of determining the barometric height which
is read from /rar (Pl. 1) by producing a vacuum above the mercury
in the volumenometer. These controls allow one to judge the accu-
racy of the data that are necessary for the calculation of the cor-
rections. The uses to which the clips /,,/,,4,,/, and the taps 4,, /,,
h:,, hy, /, and /, (during part of the observations the latter two were
replaced by clips), were put during the yolumetric operations and
particularly during the control measurements just mentioned need
no further description. We may also mention that two pieces of
wood were used to compress the rubber tube by being screwed
closer together and thus cause the mercury to rise a little so that
(following Rayneicn’s method) menisci that were easily readable
could be obtained in the desired position: the clips themselves could
also be used for the same purpose. For further details regarding
the volumenometer and its working we may refer to the papers
already mentioned and also to the forthcoming Communication an-
nounced in §°3.
The volumenometer has twice been calibrated below the zero mark,
once for the experiments published in Comms. Nos. 92 and 88, and
again for the experiments by KamernincH Onnes and pr Haas on
the compressibility of hydrogen vapour. The difference between these
two calibrations was less than ‘/,,,,,-. In this we have allowed for
the fact that the temperature of the upper portion of the volumeno-
meter (above the level §) differs from that obtaining in the bath
surrounding £. For the purpose of the compressibility research the
volume of this upper part has undergone some modification, and we
have ourselves calibrated the volumes « and «’ above the zero mark.
We have also used the volumenometer itself to calibrate the dead spaces
ke
the number of times that a tap has been turned on being opened.
By the general application of the method we have given of allowing
only a low pressure in these spaces a knowledge of their volumes
with the accuracy that is attainable by adopting these measures is
necessary Only in exceptional cases.
,—h,, h,—k,—k,, and in this, amongst other things, we allowed for
5
The pressure of the gas whose volume is fixed by bringing the
mercury meniscus in the volumenometer to one of the marks made
a
( 949 )
for this purpose is given by the difference of level between the
mercury in the volumenometer and that in the manometer tube plus
the barometric height when, as was the case in all our experiments,
this manometer tube is in connection with the constant pressure
reservoir /. The height of the barometer was given by Bar. (For
this method see Comm. No. 60, Sept. 1900, and Comm. No. 84).
As a rule the tap 4,,
tained between J/ and /; it was kept closed while readings were
being made. Sometimes, when one wanted better adjustment or
readings, advantage was taken of the tap /,, to make the pressure
was opened while equilibrium was being ob-
in R a few centimeters higher or lower than atmospheric.
§ 4. Experimental method. Auxiliary apparatus. A tap k, connects
the volumenometer with a rigidly constructed 7-piece which through
other taps connects the volumenometer and the dilatometer with each
other and with the apparatus in which the oxygen is stored under
high pressure; these are a cylindrical reservoir P, and an auxiliary
compressor A in the glass tube of which marked A, the oxygen is
contained over mercury. All parts of the apparatus can be evacuated
along &,,, &,, &
kept closed before any measurements are made and before any
; and this is of course always done, and /:,, and ¢,
oxygen is admitted to the tube A, from the reservoir P?,. When, as
is almost always the case at very low temperatures, the pressure
in the reservoir P, is higher than the maximum vapour pressure of
oxygen at the temperature of the dilatometer, the oxygen can be
simply distilled over into the dilatometer from the reservoir /,, and
by regulating the taps, the liquid can be brought to the desired level
in the graduated stem of the dilatometer. The auxiliary compressor
is brought into use in making the adjustments when the pressure
in the reservoir is lower than that of the liquid oxygen in the
dilatometer. The auxiliary compressor, indeed, by closing £,, 4, and
opening &,, k,, &, may be coupled to the dilatometer d in Cr to
form a piezometer such as is used for the determination of isotherms
(see Comms. No. 97a, Pi. 1 and No. 69 Pl. I and II): oxygen is
then admitted to the reservoir along /:,,, /,, /, and is then trans-
ferred to the dilatometer ¢ by forcing mercury into the reservoir by
means of compressed air (compare the Plate quoted from Comm.
No. 97a with that given with the present paper; the letters used are
the same in the two cases and their meaning will be found in
that Communication); the oxygen is then brought to the desired
height in the dilatometer by the admission or removal of oxygen.
At the same time one can bring the mercury in A to the graduated
( 950.)
part of the stem il, by allowing oxygen to return to 7, if necessary.
The auxiliary compressor is evacuated before the admission of mer-
cury ; it may also be used in conjunction with a metal manometer
previously calibrated with the open manometer of Comm. N°, 44 or
with the closed manometer of Comm. N*. 78 ') and with the pres-
sure gauge and seale C (see Pl. 1) for reading off the vapour pressure,
of the liquid oxygen in the dilatometer. This measurement is made
while the meniscus is in the middle of the dilatometer reservoir ¢),
and care is taken to see that equilibrium, as shown by the stationary
condition of the meniscus in A, is obtained at the same pressure,
when there remains but a very small quantity of liquid in the
dilatometer; from this it is seen that the temperature is the same
over the whole dilatometer, and in particular that it is the same
for the appendix and for the middle of the bath where the tempe-
rature is measured.
The copper cylindrical reservoir /?, with the tap &,, is of the type
that is commonly used in the cryogenic laboratory; to it is attached
a small manometer, the pressure on which shows the quantity of gas
that is still left in the reservoir. The oxygen that has been used for
the measurements can be brought back again by distillation on
immersing the reservoir in liquid air. The space between &, and /:,)
is used for taking definite small quantities of gas from P, .
For a detailed description of the arrangement of the cryostat Cr
(Pl. I of this Communication with the same letters as in Comm. N°. 97a)
and for particulars regarding the cycle of liquid gas that is used
when the bath that is being worked with is liquid oxygen boiling
under reduced pressure, we may refer to Plate I of Comm. N°. 97a
(Mareh L907) and to Comm. N°. 94d (June 1905). For the cases in
which the temperatures are given by baths of liquid methane and
liquid ethylene the apparatus is the same in principle. The place
occupied by the piezometer in the researches to which reference has
just been made is now taken by the dilatometer d. Instead of a
single resistance thermometer as was used in Comm. N°. 94d we
now used two platinum resistance thermometers*) each of them with
four leads and of the type constructed wholly of platinum and glass
(see Comm. N°. 99) § 2): the glass cylinder was heated until it was
beginning to become slightly soft and then the very fine platinum
1) We wish to record our thanks to Dr. CG. Dorsman and Mr. G. Hotsr for the
care with which they executed this work.
2) The resistance thermometers were calibrated and the temperature determinations
were made by Mrs. pe Haas—Lorenrz: we gratefully acknowledge the careful
assistance she gave us in this.
a
?
A
;
‘
‘
“
t
.
*
|
’
‘
‘
¢
,
(951 )
Wire was wound on it while it was. still hot, the ends of the platinum
wire were fused into the glass and then each of them was welded
in the blowpipe to two platinum leads.
In the present instance the cryostat vessel was a transparent double-
walled vacuum giass. In order to keep the lowest temperature always
in the bottom of the cryostat by diminishing the evaporation it was
surrounded by a second transparent vacuum glass containing liquid
air; the latter was protected from precipitation of mist on its outer
surface by another glass filled with alcohol whose temperature was
kept above the temperature of the room. (Cf. e.g. Comm. N°. 108).
When the equilibrium that was wanted for a measurement has
been reached and ihe temperature measured while the equilibrium
has been maintained, the tap #4, is closed, the volumenometer and
the dead space evacuated (keeping /, closed) and then the gas is
removed from the dilatometer to the volumenometer.
The temperature of the volumenometer is kept constant by a
stream of water delivered by the thermostat described in Comm. N°. 70.
Thermometers of the requisite accuracy for each measurement were
placed at 64 in the bath and also at 47... where they were bound
to the tubes ete. and were as far as possible wrapped alone with
them in one common layer of wool.
The volumenometer, the manometer tube with seale alongside and
the two limbs of the barometer Lar are so disposed around a three
telescope cathetometer (Comm. N°. 60) that they ean all three be
read in succession by simply turning the cathetometer round its axis.
To facilitate adjustment the barometer and the seale are placed on
small tables (Comm. N°. 95e) which allow of horizontal motion by
serew travels, and which can undergo alteration with respect to the
vertical. Electric lamps serve to illuminate small vertically movable
screens with slits placed behind the menisci, or, in conjunction with
mirrors, to illuminate other points; they are switched on in suecession
from a dial close to the cathetometer from which place the sereens
too can be adjusted to the desired height. For particulars as to the
precautions adopted during the measurements we refer to the Com-
munications already mentioned.
§ 5. Calculation of experimental results, corrections. The dilato-
meter was calibrated with mereury. For this purpose there was
temporarily fused to dq (Pl. I fig. 2) a small glass tap with a capillary
that was immersed in a tray of mercury. The volume of the meniscus
was allowed for from the data given in Comm. N°. 67 (Dee. 1900 and
Jan. 1901); for most menisci it is sufficient to regard them as
62
Proceedings Royal Acad. Amsterdam. Vol. XIII.
(SB)
segments of a sphere. The expansion of the glass was corrected for
from the data of Comm. N°. 95). The positions of the liquid in the
dilatometer stem must be corrected for the liquid in the ring-shaped
meniscus that rises up against the glass; to determine this correction
we first got the height by ‘an estimation with the micrometer eyepiece
or by a measurement made with the micrometer wire of that eye
piece; it is very difficult, however, to fix the base of the meniscus.
In the end we used the results obtained by graphical calculation of
the meniscus from the laws of capillarity *).
Finally, to determine the quantity of gas given off by the liquid
whose corrected volume we have just found from the mass of the
gas in the dilatometer up to the tap /,, we must make allowance
for the mass of gas in the dead spaces of the narrow capillary, of
the small portion dys, and of the steel capillary d, that connects the
glass capillary with the tap 4.
The temperatures of the various parts of the narrow glass capillary
depend upon the lével of the liquid in the bath. Taking this into
account they were taken from isotherm measurements, particularly
from those given in Comm. N°. 97a.
The pressures used in the various experiments were always those
of the saturated vapour; for the greater part of the measurements
they were found in the manner indicated in § 4.. For temperatures
at which the density of the saturated vapour is sufficiently small to
be caleulated, vapour pressures were found by interpolation from
the measurements just mentioned and from the earlier determinations
of Comm, N°. 107a.
Seeing that oxygen isotherms have not yet been determined for
low temperatures the densities in the various parts of the dead space
were obtained by calculation, starting from the mean reduced equation
of state VII, 1 (Suppl. N°. 19, pp. 17 and 18) given by equation III
of Comm. N°. 74 by omitting the terms succeeding © and taking
account of note 1, Comm. N°. 97a p. 24.
In this we put
in S68; Pe = 90.8
By 1 C4 1
im 273,09 2) == pp, —— 5 5 = — 3
12 a A’* 4, . gest Aa,
Ay, = 1—(Ba, + Ca,-...)
in which Ay, B4,.... are the values of Ay, By..... au OmOe
1) Mr. pe Haas, was kind enough to undertake this calculation for which we
wish to record our thanks to him,
;
NO lll
—9 6
Ajg=(1 + eayd) Aa, , «AV = 0.0036618
le AUP Se
vA vA”
(Comm. N°. 71). Since the question is one of calculation of density
at a given pressure the last equation is transformed to
puA=Agt Boe + CP 9 a D? ys drdéne
in which
Ba iv) _Casa—Ba* pp _ 2B 8448404
A4 sAVAaa Aye
(ef. Comm. N°. 92, Il, p. 18 and N°. 109, p. 7).
In exactly the same way densities at ordinary temperatures may
be obtained from the isotherms of Comm. N°. 78. These do not
BS
allow the proper evaluation of C4 in the equation given above;
on the other hand as is shown in Comm. N°. 71 AmaGart’s isotherms
are uncertain as tar as By is concerned. We therefore take the
value of Cy from VII. 1 and subsequently By from the isotherms
of Comm. N°. 78.
From VII.1 we get
DA C4
at On ae: — (2.82164 . 10-3 221255). 10-6
15°26, —0.70050 . 10-2 24221 10-6
20 Ow 53 — 0.66747 . 10-3 2.1238 .10-§
and from the tndividual isotherms (Comm. N°. 7L p. 10):
By C4
at 0° C. ==) 92.955 1Ois2 2.2931 10-8
5 ae = (07828 11053 EAP. AO—8
values which do not differ much from those deduced from VII. 1.
Limiting ourselves to the lowest pressures so that the term in C
is at the most 10°/, of that in 4 we get from the isotherms of
Comm. N°. 78.
By
at Ore Ce — 1.02843 . 10-3
Soy — 0.86388 . 10-3
202 5 — ().87466 . 10-3,
and these values are contained in the formula
10°. By = — 1,02848 + 0,008942 ¢.
A 4, = 1,00103
This formula was also used for the calibration of the steel capillary
( 954 )
i,—a with high pressure oxygen using the auxiliary compressor and
the volumenometer.
The equation that is necessary for the reduction of the volume
of a quantity of gas measured in ¢.c. in the volumenometer at a
certain pressure and temperature to the normal volume N (at O0°C.
and 760 mm.) of that quantity expressed in c.c. may also be obtained
from the equation for ordinary temperature. One can easily see from
the numbers given above that in these circumstances C\) is negligible,
so that
: pV
AA, (1 + aaryt) (eae BY)p) :
for which all the data have been found above. Let us use it to
determine the pressure coeflicient for oxygen between 0°C. and 20°C.
and for a pressure of 1 atm. at 0? C. We get 0.0036746 a number
that agrees well with that given by Jo.Ly’).
For the normal density of oxygen we have taken the mean of
the values*) given by Lepuc, Rayier@n, and Morury: 0,00142876,
0,00142905, and 0,00142900, viz: 0,00142894.
For the corrections that are applied in the calculation of the
volumenometri¢ measurements which give ye V,t, we may refer to
the Communications already quoted N°. 84, 88, 92 and to the
Communication that we mentioned in §3 as soon to appear. The
accuracy of those measurements is greater than that which we were
able to reach with our dilatomeier so that the mass data may be
taken as certain. As an example we give the following results
obtained by each of us measuring the same mass twice:
11 Nov. 1.74448
i as 1.74432
= = 17a
{di 5, al 1450,
195, eo 174429
1.74449
1.74444.
Hence we can be pretty certain of an accuracy of 1 in 4000 in
the mass.
To get an idea of the accuracy with which equilibrium to
which the measured quantity referred was actually realised,
1) Maxower and Noste’s measurements are doubtful. They give = 0.0036655
for p=O instead of 0.0036618, a value that is certainly too high.
2) Danie, Berruetor, Ztschr. f. Electrochem. 1904 p. 621,
( 955 )
after equilibrium had been reached in our experiment on the
density of the vapour and the tap &, had been closed we
altered the temperature of the cryostat slightly until the liquid
phase first disappeared and then reappeared in the appendix.
We found that a temperature change of */,, to '/,, of a degree
was sufficient to cause the liquid phase to disappear completely. The
absolute values of the temperatures are accurate to about ‘/,,th of
a degree except in one case (— 210° C.) in which, owing to
unfavourable circumstances, the accuracy attained was '/,th of a degree.
§ 6. Results. For gi, the density of the liquid oxygen, for @ ya,
the density of the saturated vapour with which it is in equilibrium
at the same temperaiure, and for D.= > (@iig + Qra,) the ordinate
Verap )
2
of the diameter we obtained the following values:
t lig Ovap DD (ous) D> (eal) O=6
= ols Geel SLO 0.0001 0.6373 0.6373 ©)
= 5220 1.1415 (0051 0.5733 0.5730 + 0.00038
SS 5 fay 8 0.9758 0.0385 0.5072 0.5107 — 0.0035
= 112 0.8742 0.0805 0.4773 0.4783 — 0.0010
— 1129°9 0.7781 0.1320 0.4550 0.4550 0.0000
== §173}.33 0.6779 0.2022 0.4400 0.4400 0
== AO! 0.60382 0.2701 0.4366 0.43385 + 0.0031
The ealeulated values of the diameter are taken from the equation.
D2 (eal) = 0.1608 — 0.002265 ¢£
The results are plotted on Plate III.
By putting ¢ equal to the critical temperature — 118.°8C. a value
9, = 0.4299 is found for the critical density. This value compared
with the value of gj, at — 210.°C., is in good agreement with the
law of the third of the density.
From
baz — 0,002265
the absolute value of the slope of the diameter D, = ay+ b, 7,
taking 7), = 273.1 — 118.8 the reduced slope is found to be
Trba
ba ee (ula).
Qk
The deviation at —154°.5 C., the density of the vapour being
1) E. Maratas. Remarques sur le Théoreme des états corresnondants. Ann. de
Toulouse t. V. $891.
( 956 )
obtained from the mean equation of state (see § 5%, is probably due
to an error in the experiment; we have been able to trace a probable
cause that would afford a complete explanation of ifs occurrence,
As for the temperature 120°4C., it is in the neighbourhood of
the critical state and ought not, therefore, to influence our conclusions.
We come, therefore, to the conclusion that the diameter for oxygen
is to a high degree of approximation rectilinear. The liquid densities
differ very little from the values given by Drwar’s experiments and
by those of Bary and Donnan. It should also be noted that the values
we have found for bg, Vy, and 0; are almost identical with the values
bp —— 0002264. — 0.800, or; = 0.4387,
deduced by one of us (KE. M.) from Werosinwski’s measurements at
low temperatures.
It may be noticed in conelusion that the critical virial quotient
was found to be
3 RT}, :
MG, 3.346
PRY kc
a value that is smaller than those for all normal substances of
higher critical temperature (see Kurnwx, Zustandsgleichung p. 60)
which run from 3.4 to 3.9; hence oxygen approximates more than
any of these to the value given by van pir Waats’s equation of
state, 2.67.
Chemistry. — “The nitration of aniline and of some anilides”.
By Prof. A. F. Honteman, J. C. Hartrogs and T. vaN DER
LINDEN.
‘This communication will not be published in these Proceedings).
(March 23, 1911).
amet
‘TTX ‘JOA ‘Weprajsury ‘peoy jedoy sS8urpooo01g
leita * WoGkXO AOJ LoJOMVIP AveMTTTZOeI OL” “SANNO HYNITHANVH “H PU® SVIHLVW O
( 957 )
Prof. Pu. Konnstamm and Dr. J. Timmermans:
ASD Deen Ds UieM:
Since the publication of the original paper (see These Proceedings
p. 865) we have determined the following:
Boiling point line of isopentane + nitrobenzene.
Temperature of the critical end-point 32.°1.
Concentration
weight of dT dT
nitroben- Boiling
& zene to dar de
100 parts point
of mixture
0.0 0.000 97°95 29°33 0-176
6.8 0.041 99)45 1529) 0.401
13.2 0.082 29.80 Gal 0.046
24.15 0.457 30.30 23) . 0.019
32.4 0.217 30.45 | 0.0 0.0
39.0 0.273 30.45 0.0 0.0
58.7 0.454 30.45 7.8 0.08)
68.45 0.556 SH ge) 3" abyss: 0.43
73.85 0.623 33.65 | 470.0 6.8
|
100.0 1.000 210.85
KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN
TE AMSTERDAM,
PROCEEDINGS OF THE MEETING
of Saturday March 25, 1911.
——=— slo Ce Ses
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige
Afdeeling van Zaterdag 25 Maart 1911, Dl. XIX).
GOVAN ERD ANP e TS
J. R. Karz: “Experimental researches on the analogy between swelling (imbibition) and
mixing”. (Communicated by Prof. C. A. PEKELMARING), p. 958. (With one plate); 2nd
Communication, p. 975. (With one plate).
H. J. Hanerrcer, J. pe Haan and F. Bunaxovic: “On the influence of icdotorm, chloroform
and other substances dissoluble in fats, on phagoeytosis”, p. 982.
bE. Hexma: “On the stimulating effect of chloride of calcium and cf intestinal mucous mem-
brane extract on the action of trypsin. (Communicated by Prof. H. J. Hampurcer), p. 1002.
HH. Kamersincn Oxxrs and C. A. Crowmenis:; “Isotherms of monatomic substances and of
their binary mixtures. IX. The behaviour of argon with regard to the law of corresponding
states”, p. 1012. (With one plate).
W UH. Anisz: “On the connection between stimulus and effect in photo-tropie curvatures of
seedlings of Avena Sativa’. (Communicated by Prof. F. A. F. C. Wenr), p. 1022.
J. Scumeutzen: “On the orientation of crystal-sections’. (Communicated by Prof. C. E. A.
WiciMann), p. 1081.
J. Scumurzer: “On the determination of the optic axial-angle from the extinction-angle with
regard to the trace of a discretional plane in a discretional crystal-section”. (Communicated
by Prof. C. E. A. WiciMany), p. 1035.
J. Seumerzer: “On the determination of an unknown plane from its traces in two orientated
erystal-sections’. (Gommunicated by Prof. C. E. A. Wicuann), p. 1045.
J.J. L. D. baron van Horvert: “Remarks on the reticular cells of the oblongata in different
vertebrates”. (Communicated by Prof. L. Bouk), p. 1047. (With one plate).
M. W. Bewerien: “Pigments as products of oxidation by bacterial action”, p. 1066.
A. A. W. Huprecur: “The Eutherian and the Metatherian early blastocyst”, p. 1077. (With
one plate).
J. Worrr: “Quadratic complexes of revolution and congruences of revolution”. (Communicated
by Prof. Jax DE Vries), p. 1084.
W. H. Jeunes and H. B. vay per Praars: “Observations concerning anomalous dispersion
of light in gases”. (First communication), p. 1088. (With one plate).
H. Kamervinen Onnes: “Further experiments with liquid helium”, p. 1698. (With 3 plates).
H. G. Cannecierer: “lonization of gases by light, emitted from Grisster tubes. Research
after the existence of selective effects in the ionization”, (Communicated by Prof. W. H.
Juuivs), p. 1114.
Errata, p. 1119,
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 958 )
Physiology. — “Experimental researches on the analogy between
swelling (imbibition) and mixing.” By J. R. Karz. (Commu-
nicated by Prof. C. A. PrkeELHARING).
(Communicated in the meeting of November 26, 1910).
Among the chapters of General Physiological Chemistry there are
few which invite to a further study so much as that on swelling.
Partly, because so little is known and understood as yet, about this
phenomenon already noticed in ancient times, and also because the
knowledge of the laws of swelling and the explanation of the imbi-
bition process prove to be of fundamental significance for physiology,
pharmacodynamics and preparative physiological chemistry.
lor physiology, because the protoplasm and the cellnucleus (which
together form the material substratum which is the seat of life) are
built up of a system of imbibing bodies and interposed liquids.
Many phenomena of life are associated with the motion of water
from those solid bodies to the surrounding liquids (or reversedly)
and between those bodies mutually. And it has often been tried to
attribute to those water displacements a fundamental significance by
making them the basis of an explanation of those processes of life.
So for instance, in the theory of the muscular contraction of ENGEL-
MANN‘), who, guided by extended morphological researches as to the
changes in the contracting muscle, has tried to demonstrate that the
transformator by which the chemical energy of the metabolism in
the muscle is converted into mechanical power, consists of a system
of imbibing bodies and acts by displacement of water between these
bodies mutually. “During the contraction the anisotropous layer swells
owing to imbibition of water which it derives from the isotropous layers
with which it comes into contact. Each anisotropous layer is, so
far as the muscular fibre extends, provided at both sides with a
layer from which it can draw water, which it can again return
when the contraction ceases.” *)
By means of this hypothesis many facts which are noticed in the
contraction of the muscle are explained qualitatively, and ENGELMANN
demonstrated by his well-known violin string pattern that the theory
can also account, more or less, for the form of the line which
') Summarized in his Croonian Lecture, Proce. Roy. Soc. vol 57, p. 411-433.
*) PEKELHARING (Voordrachten over Weefselleer, p 398) thus summarises
ISNGELMANN’S views.
represents how the length of a contracting muscle depends on the
time. But this is not enough. The success with which Werrrurm
Satomonsoy, HoorweG and others have been able to represent the
curves experimentally obtained by formulae relatively so simple,
points to the fact that the theory, if really satisfactory, will have
to lead to similar formulae. But in order to work out the theory so
far, it is necessary, however to know the quantitative laws of
swelling: to know on what it depends whether in a system of
imbibing bodies the water will, or will not, be displaced, and
according to what formulae the different properties of a swelling
substance depend on the degree of imbibition.
For pharmacodynamics. A drug absorbed in the blood, when it
has been administered in small doses, frequently affects the funetion
of one organ only and this is explained by assuming that a sub-
stance causes ceteris paribus a more drastic change in the life pro-
cesses of an organ when if is present in a greater concentration and
by the fact that different organs absorb very different quantities of
a drug from the same solution (blood for instance). This creates a
connection between clective action and relative streneth of the imbibition
in different kinds of cells‘), which has proved fruitful as a working
hypothesis. Of late years a commencement has been made to work out
this theory also quantitatively. The elegant researches of W. Srrave
on the action of veratrine on the Aplysia heart and the immuno-
chemical theories of Arrupxits may be cited as examples. In all
these calculations it is assumed that the so-called division rule of
Nernst (a sequel of van “r Horr’s laws of dilute solutions) is also
available for the imbibition of dissolved substances in swelling bodies.
However interesting and plausible these applications may appear, if
admits in my opinion of serious doubt whether in all these cases
the laws of dilute solutions have been used within their proper
limits. *) If they have not, the argument would, in some cases, not
rest on a sufficiently firm: basis, notwithstanding its apparent solidity.
This difficult) question can oniy be answered when a thorough
knowledge of quantitative laws and an explanation of the swelling
process is obtaimed.
For preparative physiological chemistry. A\l polysaccharides and
albuminous substances undergo swelling in water and it is greatly
in consequence of this property that the chemistry of these substances
‘) Compare H. J. Hameurcer, De physische scheikunde en hare beteekenis voor
de geneeskundige wetenschappen, 1901, pag. 7, 20.
*) | will refer to this impertant question in detail, later.
63*
( 960 )
is of such a peculiar character. The criticism of the methods for
the purification of these substances, the characteristics of their purity,
the question whether the water contained in imbibing crystals may
be put at least in part on a par with the water of crystal-
lisation of inorganic salts’ (as pretended by Hoppe Sryiur*) and others
in the case of oxyhaemoglobin crystals), the question whether the
molecular weight of the imbibing substances can be determined from
the decrease of their water vapour pressure, and so many other
questions of that kind, are problems which the physiological chemist
has, so to speak, to face daily, but which cannot be treatea fully
before the quantitative laws of swelling, and a due explanation of the
same shall have been discovered.
But relatively litthe being known of this matter at that time, |
have been engaged since the sumimer of 1904 upon an extensive
research in order to get a better insight into these quantitative laws
and their explanation, Very soon, some remarkable regularities and
analogies were brought to light. [ thought it desirable, however, not
to publish these results before they had been confirmed so repeatedly
that they could not be looked upon as being merely accidental.
in October 1906 T had found the analogy now deseribed in this first
publication, and communicated the same to my teachers Profs. H. W.
Bakntis Roozupoom and A. Smirs. In this paper [ will give only
a brief and partial account of the experiments carried out. For
experimental detatls and the literature on the subject the more extended
publication which will appear shortly, should be consulted.
Short description of the phenomena of swelling.
Before describing the researches on imbibition it appears to me
desirable to point out, briefly, which phenomenon I have studied,
from which similar, but yet different, phenomena it must be distin-
euished, and in which substances if is met with. This seems to me
particularly desirable because these facts are sometimes mentioned
in physics and chemistry under another name.
By swelling ov imbibition power*) the biologists understand the
') Gp. Scuirur’s Textbook of Physiology, 1. p. 205 (1893).
*) The majority of investigators understand by imbibition power the same
as swelling power. Remyke (Hansrern’s Botan. Abh. IV, p. 2 and 3) differs
a
from this view; his idea of imbibition power includes porosity as well, | do not
a
(961 )
property of some solid substanees, which under the most powerful
microscope do not show visible pores, to occlude liquids between
their smallest particles. If they are examined again after the absorp-
tion of the liquid it is impossible to distinguish the separate particles
of the liquid and the solid substance even when using the most
powerful lenses.
During this absorption of liquid the smallest particles of the solid
body are separated from each other by the penetrating molecules of
water. Rrmke has called this increase of the distance between the
particles the ducrease of disgregration of the solid substance. Because
those particles get at a greater distance from each other, the volume
and length measurements of the solid body suffer an increase *) ;
henee the name ‘swelling’. At the same time the cohesion between
the particles of the solid substance appears to have much decreased *).
On the other hand we may expect that there will exist a great
affinity between the water and the solid body if this is able to
overcome the so powerful cohesion of the solid substance. This
suspicion is confirmed; during the swelling a considerable amount
of heat is liberated‘) and an important contraction of volume takes
place, in other words, the volume of the swollen body is considerably
smaller than the sum of the volume of the solid substance and that
of the imbibed water.
On drying, the swollen bodies can again part with the liquid
absorbed; if this takes place slowly the homogeneity is retained. The
phenomenon is — at least in the main -— reversible.
Some swelling bodies, such as casein, wood, ete. when placed in
contact with saturated water vapour absorb only a limited quantity
of water and a so-called maximum of imbibition is reached (bodies
of limited imbibition power); others such as gum arabic and peptone
take up an unlimited amount of water causing them to become more
and more fluid so that they, finally, get converted into a liquid
mixtiire of water and imbibing substance (bodies of unlimited imbibition
power).
agree with him. The above definition is borrowed from HuGo pm Vrms, Leerboek
der Plantenphysiologie, 4e Ed, p. 149-150 and from H. A. Lorenz, Leerboek
der Natuurkunde, 2e Ed., Vol. [, p. 419.
1) Sometimes very considerably; peas double in size, {trish moss (Chondrus
crispus) swells to treble its size. (HuGo be Vrins, loc. cit. 4e Ed. p. 150).
*) Remke (loc. cit. p. 31) found that if air-dry Laminaria absorbs 300°/, of
water its ductility increases sixty fold while the breaking strain falls to one-tenth
of its value.
5) If amylum tritici, dried at 90°, is stirred with its own weight of water, the
temperature rises more than 10’ (N&Getr, Theorie der Gahrung, (1879'p. 133-134)
( 962 )
On no aeconnt must imbibition de confounded with the porosity
of some solid: substances such as bricks, gypsum, and others which
by surface adsorption and capillarity can absorb liquids in vésible
preformed pores. NXewir?) in 1858 already pointed out the difference
between these two properties. In the porous absorption of water, the
particles of the solid body are not forcibly separated; there is no
increase of disgration, therefore no increase in size and no loss of
cohesion. Typical imbibition is, therefore, sharply distinguished from
typical porosity.
It is principally among the products derived from living organisms
that the imbibition power is often, in’ fact almost regularly, met with.
Not only nearly all such substances (cellular walls, fibres, flour,
wood, whalebone, leather, horn, ete.) possess swelling power but the
pure physiologico-chemical compounds derived therefrom appear to
possess these properties also.
Yet, the imbibition power is not limited exclusively to substances
of vital origin. It is also observed in synthetically prepared and in
inorganic substances; as instances, [| cite copper ferroryanide, clay,
tricalcium phosphate, and silicic acid.
The solid substances capable of imbibing water *) are amorphous,
crystalline, or organised. The majority is amorphous that is to say,
possesses no visible regular arrangement of particles *).
1) Die Stiirkekérner, Ziivich, Ff. Scuutruwss, 1858, p. 332, 343.
2) Substances are known which absorb liquids other than water; caoutchoue,
for instance, imbibes ether, oil, pyridin, and even liquid carbon dioxide; nilro-
cellulose swells in alcohol-ether mixtures and in nitroglycerol It is possible that
the imbibition jaws in some of these organic liquids are more simple than in the
case of walter because this is partly associated to complex molecules (perhaps
11,0.) and because the association degree of the imbibed water must necessarily
alter. For physiological purposes the behaviour with water is, for the moment, the
most important matter and therefore, | will limit myself to this.
On the imbibition in aqueous solutions of salls, whereon Hormetsrer, Spiro,
Pauntt, Wo Osrwatp, H. Fiscaer among others have made interesting experiments,
I will deal when | have dwelt on the imbibition power in pure water.
‘) In practice it is sometimes difficult to decide whether an imbibing substance
is amorphous or crystalline. For, the external form of a typical erystal, with its
regular limitation by flat planes, may be wanting without the substance ceasing
lo be crystalline. On the other hand an amorphous swelling body may, owing to
tensions on drying, exhibit optical phenomena which remind one strongly of those
by a crystalline substance (compare the experiments of Ampronn, Ber. der Siichs.
(esellsch. d. Wiss. 1891 p. 349. The mere presence of anisolropismn is, therefore,
nol in the least sufficient to prove a substance to be crystalline. So long as crystal-
logvaphy does not threw more light on this obscure question, IT think it best to
look on imbibing substance as amorphous, unless there is suflicient evidence to
call it crystalline or organised,
a...
( 963 )
The existence of selling crystals is in ny opinion one of the
inost. remarkable facets which have become known in the study of
the imbibition phenomena. It is certainly very striking that atypical
erystal with its characteristic optical phenomena and corresponding
cleavage planes can imbibe water without loss of its crystal nature
and its homogeneity. But it creates still more surprise to notice that
all known erystals of polysaccharides or albuminous bodies undergo
swelling in water. It does not seem easy to explain how a erystal
can swell while preserving its crystal nature. But no theory of
imbibition ean be called satisfactory unless it can fully account for
this fact. The swelling crystals appear to me the touchstone of the
imbibition theories.
Next to the amorphous and the crystalline swelling bodies, organic
nature yields quite a series of products such as starch granules, bark
fibres, woody fibres ete. which possess no crystal form, but instead,
an arrangement of particles with corresponding optical phenomena
and cleavage planes '). Some investigators have felt inclined to look
upon these so-called organised bodies *) as: crystals with atypic limi-
tation planes; others as amorphous substances wherein tensions occur.
Neither of these two ideas seems to me quite satisfactory. And, provi-
sionally, I think the best thing is to look upon the organised matters
as a separate group, being more or less a medium between the
amorphous and crystalline substances *).
The analogy between swelling and mining.
The fact that a certain analogy exists between the processes of
swelling and mixing had been already observed by BerrnoLtirr in
1808. In his “Essai de Statique Chimique” he explains both pro-
cesses by the same mechanism '). The physiologists who have worked
in the third quarter of the nineteenth century on the subject of
swelling — I only mention, Cart Lepwic, NiGrni, Reinke — also
show in their publications in various places that they have noticed
the existence of that analogy.
!) Illustrations are given in each test-book of botany.
2) Amongst the organised bodies must also be reckoned the avisotropous layers
of grained muscles.
*) Whether it ts more in particular amongst the organised bodies that the much
looked for continuity between amorphous and erystalline aggregation condition
is perhaps to be found, is a question which | can only propound, but not answer.
Cf. also the facts mentioned by W. Prerrer, Pflan,enphysiologie I, p. 69—70,
*) Compare Vol. 1, p. 34 and 38.
( 964 )
In order to get a elear idea of the analogy one should imagine a
space containing water vapour in which are placed near each other
a globular shaped imbibing substance (for instance a piece of sharply
dried gelatin or gum arabic) and a drop of a liquid which is not
readily volatile but easily mixes with water (for instance sulphuric
acid or glycerin). Both now appear to be hygroscopic, both absorb
water without loss of homogeneity; both /ncrease in size because
the volume of the mixture like that of the swollen substance is,
approximately, additive and beeanse the substance remains homo-
eeneous during the water absorption. By this dilation without loss
of homogeneity ') the particles of the swelling body, like those of
the sulphurie acid, or glycerin get further removed from each other ;
in both the disgregation, as Reinkt calls it, of these particles increases.
If the two phenomena are compare! more closely, it appears in both
cases that the water absorption is a¢companied by a considerable
evolution of heat and a decided contraction of volume. There is only
one point of difference between the two phenomena; the swelling
body possesses the solid aggregation condition and retains the same
during the absorption of the water whereas the miscible substance
is liquid and remains liquid.
This gulf is, however, more or less bridged over by what is
observed in the substances with unlimited imbibition power. If, for
instance, powdered gum arabic is allowed to take up moisture, it
begins to cake when 30°/, of water has been absorbed, with 40 °/,
it forms a plastic mass, with 60°/, it is still solid but soft and
when 110°/, has been absorbed a watery solution of gum arabic is
obtained which becomes less viscous on further dilution. Ovoalbumin,
peptone and dextrin behave in the same manner. Here we see how
typical swelling substances gradually become aqueous mixtures, owing
to water absorption. The two phenomena, therefore, not only resemble
each other, but must be indeed closely related. Or perhaps even
identical >
The older investigators have not dared to assent to the identity,
1) One might perhaps object that the aqueous solution of gum arabie so formed
is not a real but a colloidal solution. In the case of substances such as gum
arabic, dextrin, and peptone, the difference belween real and colloidal solution is
but very slight. That this objection is not of great importance is shown by the
fact that solutions of substances devoid of colloidal properties such as fructose
(which has a low molecular weight and possesses normal values for the lowering
of the freezing point and the elevation of the boiling point) are also gradually
converted on drying (if erystallisation is prevented) into a solid substance having
all the properties of a swelling substance. The sodium salt of glycerol-phosphoric
acid behaves similarly.
cea i ani it i i ee
( 965 )
although they noticed plainly the close relationship. Reinke, who in
1579 discussed *) the analogy and observed it more keenly than any
one before him, evidently still hesitated — as in fact all his con-
temporaries would have done — to assume that méscrbi/ity should
exist in the so/id condition.
But the development of physical chemistry in the last: twenty-five
years has removed this difficulty. In £590 Vay ’?r Horr published his
celebrated theory of the solid solutions, which shows that miscibility
exists in the solid condition just as well as in the liquid state, and
the cases have become almost innumerable where this miscibility
has been actually observed. In consequence, the difficulty of the
older writers has been removed and now, I ask, what can still
prevent us from assuming that swelling means mixing *), in other
words that when a solid substance sivells in water, this depends on
the formation of a sohd solution of water in the imbibing body *).
Of great significance to the problem of imbibition, seems to
me to be TamMann’s idea *
many cases nothing but liquids of very great viscosity. TAMMANN
) that amorphous solid substanees are in
showed that all possible liquids, if they are cooled rapidly enough
to prevent crystallisation, become gradually more and more viscous
and are converted, without any discontinuity, into solid amorphous
bodies; known = instances of this are glass, cane-sugar, elycerin.
This view, also warmly defended by Bakavis Roozesoom and O.
LEHMANN, throws a remarkable light on the fact that the sub-
stances of unlimited imbibition power (which are all amorphous),
when absorbing water, are converted continuously into aqueous
solutions. It leads us to the hypothesis that amorphous swelling bodies
are substances of so great a viscosity that they practically possess the
solid aggregation condition, but have still retained their miscibility
with water.
If this hypothesis is correct the swelling of a piece of gelatin and
the water absorption of such liquids as sulphuric acid and glycerin
1) Loe. cit. p. 123—198.
2
*) The substances of limited imbibition power would then be analogous to
those of limited miscibility, those of unlimited imbibition power to those of un-
limited miscibility. Limited and unlimited miscibility are not different properties ;
in substances with a critical mixing point both pass into each other at a change
of temperature.
*) Similar hypotheses have been propounded repeatedly by physico-chemists.
But they have not worked out this supposition any further, to ascertain whether
it can be used as a working hypothesis in the investigation of the quantitative
laws of the imbibition power.
*) Compare Zeitschr. f. physikal. Chem, 25, p. 469—479.
( 966 )
will not only agree qualitatively but the gaantitative laws of the tive
phenomena will probably he the same.
Keperimental research as to the analogy in the quantitative
lavs Of the tivo phenomena.
Whatever value one likes to attach to the theory of imbibition
advanced, if leads in any case to a thesis which can be controlled
experimentally.) | have, therefore, instituted a comparative research
as to the quantitative laws of imbibition in a number of amorphous
swelling bodies and as to the miscibility in a namber of comparable
miscible substances; as such [| have chosen three liquids, which like
imbibing bodies are practically non-volatile and can like these absorb
large quantities of water, namely sulphuric acid, glycerin and ortho-
phosphoric acid.
In the case of a number of amorphous swelling substances, 1
determined, experimentally, the quantitative relations according to
which the heat of imbibition, the water vapour pressure and the
volume contraction depend on the degree of imbibition; the results
obtamed were represented graphically. In a few cases T could make
use of measurements executed by other investigators.
Afterwards, I did the same with the three miscible liquids. For
the greater part I could make use here of measurements already
carried out by previous investigators for other purposes. But the
Water vapour pressures of glycerin- and phosphoric acid-mixtures
had to be determined by myself and the heat generated on mixing
elyeerin and water was measured in a series of experiments carried
out jointly by myself and Mr. J. J. P. Vateron.
When choosing the swelling substances investigated, | have been
careful to avoid unnecessary complications. For instance, such sub-
stances as amylum in which layers rich in moisture occur alternately
with layers poor in moisture do not seem to me suitable for the
research; for each of these layers has a different imbibition power
and the phenomenon observed is composed of the sum of numerous
elementary phenomena which obey different laws. A fortiori intricate
products such as peas or Laminaria in which all kinds of elements
as cell walls, cell nuclei, starch granules ete. are adjacent to each
other are quite out of the question. | have also avoided using sub-
1) experiments of Biscuit, van BemMeLen among others suggest that in some
swelling substances there may be complications, so that the water absorption is
not only due to swelling, but partly to capillarity (in preformed pores). In such
cases we might expect to find different. quantitative laws.
—
a
—
( 967 )
stanees such as freshly precipitated silicie acid, or metalhe hydroxides
Wherein probably slow chemical changes take place. For instance
the blue cupric hydroxide when in contact with water gradually
changes to the black oxide — slowly at the temperature of the room,
rapidly at the boiling heat; the brown ferric hydroxide turns red,
stannic acid passes into metastannic acid and. silicic acid requires an
increasing amount of potassium hydroxide to redissolve. Fortunately
in the case of albuminous substances and polysaccharides (of which
the biologically important substances mostly consist) such complications
do not seem to occur; spontaneous peptonisation, which might ocenr
to the mind, does not proceed (at the temperature of the room, and
Whilst possessing a neutral reaction) with appreciable velocity. In
those cases where I have extended my researches to metallic hydroxides
ete. I have provisionally, confined myself to substances which by
ageing artificially — prolonged heating under water —- had been
freed as far as possible from this complication. To make quite sure,
the samples of the other substances tested were at least one year old.')
a. Heat of imbibition and heat of mixing.
The quantity of heat | I) was determined (in gram calories) gene-
rated when one gram of dried substance?) takes up / gram of water ;
this quantity T will call the imbibition heat at the imbibition degree 2*).
The substance was put into a glass tube fitted with an india rubber
stopper which was then piaced in a calorimeter filled with water
until there was an equilibrium of heat. By smashing the bottom of the
1) All the substances were investigated in the powdered condition: check ex-
periments had shown that the water adsorplion at the surface of the grains of
the powder was so small that no hindrance to speak of occurred.
2) The name “dry substance” is somewhat vague. | chose as such the substance
dried at 1109 in vacuo over sulphuric acid. In this manner all the different sub-
stances have been oblained as much as possible in a comparable condition.
The substances with the lowest water content with which | have carried out
measurements were those dried over sulphuric acid at the temperature of the
room; the values for the ‘dry’ substance were obtained by extrapolation. In the
case of a few substances which cannot be heated to 110° without decomposition
I have determined the water by drying in yacuo over sulphuric acid at the tempe-
rature of the room; this is then mentioned separately. RobewAnp and lis pupils
Karrew and Vorsenr applied this method of water determination to all substances
they investigated. The results of the two methods usually differ 1/, lo 1°.
3) The imbibition degree ¢ therefore is the number of grams of water 7 absorbed
by one gram of dry substance.
( 968 )
tube or by pouring over the content of it the substance was broueht
into contact with the water and the rise im temperature read off.
The form of the curve indicating how IW depends on ¢ has been
determined with six substances, of which T only communicate those
of cellulose (ash-free filters’ of Scutmicner & Scniin.,) and casem (pur.
Honcuster Farswerke)!). Of the curves published by other investigators,
only those of Roprwanp and Karrein for artijicially prepared starch
granules *) and of Vorsenr tor prepared woody fibres") (as in the
determination of erude fibre) seem to me fit for comparison with
liquids The other substances investigated by Roprwanp and Karpin
were species of amylum which, owing to their stratiform structure,
form more intricate objects; but there also curves were found which
in form agree completely with those of artificial starch granules *).
On the annexed illustration the curves of these four substances,
carefully drawn to scale, are shown. All four make the impression
of a hyperbola; this is particularly striking in the ease of cellulose
and casein °).
In the case of the other two curves and the cellulose I have
questioned whether they may, indeed, be represented by the formula
of the hyperbola
The subjoined tables show that the agreement is satisfactory °).
1) | beg to offer my sincere thanks to the directors of the Hoechster Parbwerke
vorm. Mersrer, Luciws and Briinina for kindly placing at my disposal the casein
required for these experiments.
2) Zeitschr. f. physikal. Chem. 33, p. 551.
3) Untersuchungen tiber die Quellung der Holzfaser, Inaugural-Dissertation, Kiel
(1896) p. 32. VonBenr had also observed that the line determined by him had
the character of a hyperbola.
4) Amylum solubile (Merck) is, for reasons to be stated afterwards, not fit to
be compared wilh liquids; for the vest it presents a line of the same form.
5) In the case of the other four substances which I have investigated, lines were
also obtained which make the impression of hyperbolas.
5) The deviations are not much greater than the presumable experimental errors.
ee
( 969 )
HEAT OF IMBIBITION OF CELLULOSE. HEAT OF IMBIBITION OF ARTIFICIAL
STARCH GRANULES.
— 6 — 130 <2 —=().59 : : . c
ee ee 0,0 Be dry = dried in vacuo over sulphuric acid
= at the temperature of the room.
F | W | W s NES ce B=0448 sx A? ee
wpa x |
eee ira if Ww W ‘ |
| : j lat | determin. calculated. BS |
Oo | eo. 0.— | : et I seu sea
0.014 | 3.5 Soll OTe = i We (uN 0.0 |
0.04 | 6.9 6.7 — 0.2 | 0.0136 | 4.4 30 WSO
| 0.054 | 7.6 7.9 — 0.1} | 0.0936 6.8 6.4 ="
or ie = mihi : P
| 0.074 | 9.0 8.3 = Og | 0.0347 | 8.4 8.9 |+0.5
| 0.261 | 10.5 10.4 | —0.1 | | 0.0494! 40.4 10.4 | 0.0) |
anki. ve 0.0549 | 12.2 12.6 | 40.4 |
0.0970 18.3 1.4 | +04
| 0.4218 | 24.0 4.4 | +0.4
| 0.1716 | 95.3 D510) |= n083
0.2403 29.5 28.9 ==(0%6
| 0.3135 Sy). I Bylely = (08)
0.3811 Beh fe I (07
HEAT OF IMBIBITION OF WOODY FIBRES.
(determination of crude fibre).
A = 23.62 B = 0.0895 = A? =0A9
| |
WwW WwW
determin. calculated
0.0370 6.7 6.9 + 0.2
0.697 | 10.5 10.3 — 0.2 |
0.0924 11.9 12.0 + 04
0.1269 14.0 13:8 | £02
0.1525 15.0 14.9 + 04
0.1742 | Af 15.6 + 0.4
0.1964 | 16.2 16.2 ++ 0.0
OMZAGG | 16.5 16.7 + 0.2
(970 )
On the same illustration are shown the curves'of the heats of
mixing for sulphuric acid, glycerin, and orthophosphorie acid: (here
again the heat of mixing JI” represents the number of gram calories
generated when one gram of dry substance takes up ¢ gram of
water. They exhibit a strong resemblance to the curves of the heat
of imbibition.
The two subjoined tables prove indeed that they may be repre-
sented by a hyperbola.
HEAT OF MIXING OF SULPHURIC ACID HEAT OF MIXING OF GLYCERIN
AND WATER. AND WATER.
(THOMSEN). d = 1640 B=0.81 2Aa?=05).
A= 182.10 B=0.3303 2A*=1.00
|
F W Ww x stl lene W 3
determin. calculated determin. calculated
0.— (0) = (= 0.— 0.— 0.— —
0.1837 65.04 65.07 +0.03 0.1800 3.3 3.0 — 0.3
0.3674 96.02 95.88 | —0.14 0.3508 Set 5.0 — 04
0.5511 113.55 113.86 +0.31 0.609 6.9 7.0 +04
0.9185 133.65 133.93 +928 1.234. 9.8 Se) + 0.4
1.653 452.45 151.78 | —0.67 1.788 11.2 11.3 + 0.0 |
3.490 165.74 166.34 --0.60 3.061 13.0 13.0 + 0.0
ere 6.170 14.2 14.5 | 0.8
9.952 14.9 15.4 4+ 0.24
12.32 Abo 15.4 + 04
25.35 16.4 15.9 — 0.5
Indeed, THomson *) was able in 1883 satisfactorily to express his
researches on sulphuric acid by means of this empirical formula *) ;
and VAN pDER Waats’s theory of mixtures leads to the same law. *)
As will be noticed the analogy between the quantitative laws of
swelling and miscibility is striking indeed.
1) Thermochemische Untersuchungen, Vol. Ill, p. 8.
*) E. Bose, (Physikal. Zeitschr. 6, p. 548-553) also praises the beautiful
results which enabled THomson to represent his measurements of the heat of mixing
by the hyperbolic formula.
5) Continuitait des gasf6rmigen und fliissigen Zustandes, Vol. II, p. 45; as a
matter of fact this deduction is made for non-associating substances only.
( 971.)
hb. Water vapour pressure.
In the case of forty swelling substances, | have determined the
curve according to which the aqueous vapour pressure of the swollen
body depends on the degree of imbibition. That pressure has been
expressed as fraction (4) of the maximum pressure of water vapour
at the same temperature. *) Such a line which is characteristic for
the manner in which the imbibition water is contained in a substance,
1 will call the hygrometric line of the swelling substance. The deter-
minations were carried out according to a method which agrees in
the main with the one employed by van BreMMELEN *).
Of eight of these substances, the lines, again drawn carefully to
scale, ave shown in the illustration. *) They ave casein, cellulose, gelatin
(the best commercial, after being thoroughly washed with water), peplone
(amphopeptone prepared by Dr. G. Grisivr according to Ktuxn), gun
arabic (finest commercial, in powder), serwmalbumin (Albumin aus Blut
puriss. Merek, dialysed, filtered and then evaporated at the tempe-
rature of the room), fricceiun phosphate (calcium phosphoricum
tribasicum siceum Merck) and cartijicially aged silicte acid (acumid
silicum Merck, heated for half a year under water at 80°C.). The
first three and the last two have a limited imbibition power, the
fourth, fifth, and sixth an unlimited one; some of these substances
belong to the albuminous bodies, others to the polysaccharides, others
again to the inorganic compounds. Although substances of a very
different nature have, therefore, been used, all lines appeared to
possess the same form‘). With small degrees of imbibition the curve
} This quotient alters but very little on the ri-e ov fall of the temperature ; it
is, therefore, advantageous to express the vapour pressure in that manner,
2) The difference with VAN BremMeLeN’s method chiefly consisted in the fact that
a same portion of the substance did not pass successively through the different
equilibria but that different portions of a same substance, after the same prelimi-
nary treatment (maximum drying or drenching), came each simultaneously in equi-
librium over another sulphuric acid solution This considerably shortens the time
of the experiments otherwise so tedious.
i
5) A double arrow | on the curve indicates that the equilibrium was approached
from two sides, a single arrow * or ¥ that it was reached from one side only
and from which one. Check experiments with numerous substances have shown
that the form of the lines obtained is the same whether the one or the other
method is followed and that the equilibria reached differ but little quantitatively.
') Apart, of course, from this difference that the curve for = 1 terminates
with substances of limited imbibition power in the imbibition maximum, whereas
with those of unlimited imbibition power, it takes an asymptotic course. But for the
rest the lines of these two groups exhibit no difference.
( 972 )
begins to tur its convex side downwards, gets at a greater 7 a
point of inflection and then turns the concave side downwards,
forming a more or less S-shaped line.
So great an agreement with compounds so different chemically is
somewhat surprising *).
Apparently different from: this are some of the results obtained by
van Bemmenen. When experimenting with silicic acid freshly precipi-
tated from soluble glass by hydrochloric acid and with ferrie hydrox-
ide recently precipitated by alkali from ferric chloride he obtained
lines much more complicated, with three points of inflection. If, however,
Wwe examine the curves which he obtained from o/d silicic acid *)
and ferric hydroxide *) more closely, they appear to possess the
same form as I have found.
In the case of mixtures both experiment and theory lead to the
conclusion that the line which indivates how the aqueous vapour
pressure depends on 7, can have two types which gradually pass
into each other. With some substances, for instance with propionic
and acetic acids, the coneave side is, from the commencement,
turned downwards and the point of inflection has disappeared, Glycerin
appears to lie exactly on the border line, the curve represented
still just shows the point of inflection.
The swelling bodies have, therefore, lines which agree with those
of the miscible substances of the first group and bear, indeed, aclose
resemblance to these.
This analogy goes still further: miscible substances of the first
eroup have a strong heat of mixing and contraction of volume ; in
those of the second group these properties are mostly but feebly
positive or even negative. In all the imbibing substances, as yet
investigated, they are strongly positive.
The theory of the mixtures makes one suspect ') that the initial
2) Curves of the same form were obtained by Trouron with flannel and cotton
wool, by Orme Masson and Richarps with cotton wool, by LowEnsrErN with
cupric ferrocyanide, zine ferrocyanide and silicic acid formed by the action of dilute
acid on silicates at the temperature cf the room. I myself, have examined more
than thirly other swelling substances, among those bemg the majority of tbe
known physiologico-chemical substances and a few other products such as tannins
and soaps; the curves invariably exhibited the S-shaped character
5) Zeitschr. f. Anorgan. Chem. 13, p. 394 (fig. 17).
') Zeitschr. f. Anorgan. Chem. 20, p. 207. The line of the jelly which has been
kept under water for seven years is meant.
') This follows from the approximative formulae for concentrated mixtures
deseribed by Nerysr as the formulae of the “ideal concentrated solutions” and also
from the expression derived by Van Laan from Van per Waat’s theory of
( 973 )
turning downwards of the convex side (and the point of intlection caused
thereby) will be the more pronounced in a miscible substance of the
group when the so-called ‘differential heat of imbibition for 7—= 0”
is larger, that is to say, the quantity of heat generated when a large
quantity of dried substance absorbs one gram of water *). With
sulphurie acid this character of the vapour pressure line is more
strongly pronounced than with phosphoric acid, and with this sub-
stance considerably stronger than with glycerin. As will be noticed
from the curve, the behaviour of the imbibing bodies lies more or
less between that of sulphuric and phosphoric acid. We may, there-
‘fore expect as probable that the said heat quantity is greater
in sulphuric than in phosphoric acid and much larger than in gly-
cerin, and that in swelling bodies its values le between those of
the substances mentioned first. That such is indeed the case is shown
by the subjoined table for the value of this quantity which I have
calculated for the different substances from the caloric experiments.
Gaseimes) oe ss a es 200P cals sulphuricsacidia. = obON call
cellulose . . . . . . . 390 ,, orthophorphoric acid 100 ,,
wrtiicial starch granules . .320' ,, glycerm +» | . . 20) ,,
woody fibres (estimation of
crude. fibre)h .: 5°. .*.. 260 ,,
nuclein (from yeast) . . . 200 ,,
In the aqueous vapour pressure we find therefore also a resem-
blance, to in many details, between the quantitative laws of swel-
ling and mixing.
c. Volume contraction.
In the case of three amorphous imbibing substances I have deter-
mined to volume contraction ¢ (in ce) which takes place when
one gram of dry substance absorbs 7 grams of water. The method was
mixtures, for the vapour pressure of mixtures. Particularly in the case of the
dilatable substances the formulae of Nernst seem to me to become of great significance.
They predict for instance, that if the heat of imbibition is represented by a hyper-
bola, the hygrometric ne must have the S-form, and various particulars of this
line which are actually observed. I will refer to this more fully shortly in an
article on the Thermodynamics of the Swelling Process.
*) The differential heat of mixing is calculated from the ordinary heat of mixing
dW
di
according to the formula # =
64
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 974 )
quite the same as that described by Ropewanp for amnylum tritici’).
Petroleumether (b. p. 80°—100° ©.) was used as pyknometer-liquid
which, as proved by check experiments, is not imbibed by the sub-
stances employed. Of the lines determined only those for casein are
viven; with the other substances I obtained lines of the same shape.
I also had reproduced on the illustration the results of Roprwa1p
with amylum tritici, although these experiments are not of great worth
for the purpose of comparison with liquids, owing to the presence
of layers in the starch granules (in amylum tritici, however, this
alternate construction shows but faintly). In both cases the curve
exhibits the form of an hyperbola.
In the three miscible substances were found volume contraction
lines of the same form *); these curves also make the impression of
being hyperbolas *). In the volume contraction we also find, therefore,
the same analogy in the quantitative laws of the two phenomena.
d. Connection between heat of imbibition and contraction of volume.
If the volume contraction c of a swelling substance is divided by
the heat of imbibition (JV) at the same degree of imbibition, figures
are obtained which, in the different imbibing bodies, are in the
same order of magnitude. As this relation often changes considerably
with the degre> of imbibition, I calculated -— in order to obtain
. c
comparable values — the quotient
for very small 2’s @= 0).
In the three miscible liquids this quotient has also values which
agree very well.
What is now particularly striking is that this order of magnitude
is the same with miscible and with swelling substances. The subjoined
2 c
table gives the value of (Z))
10
Ww
CASEI ate See ere ee ee O01 sulphuric acid . 0.0020
amylumetritic:.) | 28s) 2 0: 0019 orthophosph. acid. 0.0010
woody fibres (crude fibre determ.) 0.0021 glycerin. . . 0.0024
1) Zeitschr. f. physical. Chem. 24, 201 —202.
2) Calculated from experiments of DomKke for sulphuric acid (Lanpott, Bornste,
Meyernorrer’s Tabellen 3e Ed., pg. 328), of Scutrr for phosphorie acid (Lieb.
Ann. 87, pg. 192); of Lenz for glycerin (Lunex’s Techn. Unters. Meth. IIl, pg. 160).
5) THomson had pointed already out in 1883, that the volume contractions of
acetic acid by mixing with water follow a hyperbola.
(975
In swelling, as well as in miscible substances, the quotient,
therefore, always lies tetween 10 and 25> 10-*; however
different the chemical nature of the substance may be! If the two
phenomena are identical in nature, this need not cause astonishment.
But how could this agreement in order of magnitude in such greatly
different substances be explained if the two phenomena were different
in principle ?
Summarizing, we see that the laws of imbibition are relatively
simple (much simpler than one would have expected after van
BeMMELEN’S experiments) if only care is taken to avoid substances
with secondary complications. And it appears that in the four cases
where the quantitative laws of the imbibition power of amorphous
solid substances were compared with the laws of the miscibility
of liquids, a striking analogy exists. The correctness of the fact that
this analogy eaists is independent of the correctness of the theory,
which has led to the research. But once found it is a fact with which
every theory of swelling will have to reckon.
But whereas it forms a strong confirmation of the theory which
proclaims that swelling is in principle the same as mixing, it will
be difficult to propose any other theory which can explain uncon-
strainedly the existence of this analogy.
In a subsequent paper | hope to publish a number of experiments
showing that the theory can also account satisfactorily for the imbi-
bition power of swelling crystals.
Physiology. — ‘“LKxperimental researches on the analogy between
swelling (imbibition) and mising. 2°¢ Communication : Srelling
(imbibing) crystals and mired crystals’. By J. R. Karz.
(Communicated by Prof. P&rkeLHarine).
(Communicated in the Meeting of December 24, 1910).
Experiments with swelling (imbibing) crystals.
The question as to how the water of imbibition exists in swelling
crystals '), has for a long time excited great interest, but a clear insight
is not yet obtained. In order that some more light may be thrown
on this question it appeared supremely necessary to carry out new
') Literature reviews on imbibing crystals are found in:
Q. Leawann, Molekularphysik II, p. 550—553 (1888).
L. Maittarp, Revue Générale des Sciences 9, p. 608—614 (1898).
Ir. N. Scnunz, Die Krystallisation von Eivweisstoffen, Jena, Gusrav FiscHer.
64*
(976)
experiments. For those executed up to the present, are too few in
number to serve as the basis of a fruitful discussion as to the value
of the different theories.
In the first place then we want the determination of the line
according to which the water vapour pressure of a swollen erystal
depends on the degree of imbibition.
In a number of imbibing crystals, therefore, I have determined
the form of this line. The water vapour pressure was expressed as
a fraction (/) of the maximum pressure of water at the same tem-
perature, the degree of imbibition as the number of grams of water
(7) absorbed by one gram of dry substance (hygrometric line).
In the first place I have made experiments with pure carbon
monoxide-haemoglobin from horse’s blood and from dog’s blood, which
I prepared according to the method described by PrkeLnarine *), in
his laboratory and under his guidance. The substance investigated
consisting of small beautiful rhombic erystals was pressed dry between
two plates of unglazed porcelain and then placed in small weighed
glass dishes over sulphuric acid-water mixtures of known vapour
pressure until an equilibrium was attained; care being taken that
the small glass bell-jars in which these experiments were carried
out, Contained sufficient carbon monoxide to prevent dissociation of
the compound. The substance now in equilibrium was, after a
spectroscopic test, found to consist of pure carbon monoxide-
haemoglobin and not a trace of methaemoglobin could be detected *).
In each of these portions of the compound the water content was
determined by drying in an airbath at 115°. The experiment was
made once with carbon monoxide-haemoglobin from dog’s blood
and twice with that from horse’s blood. The results of these last
two experimental series agreed very well mutually, anew indication
that pure haemoglobin has a composition of relatively great constancy.
The hygrometric lines obtained have been reproduced in the
illustration. They exhibit a continuous course, quite different from
that of the salts containing water of crystallisation. In the latter, the
vapour pressure, when the water content increases, remains constant
until the salt has been completely converted into hydrate; if then
ihe substance takes up still more water, another hydrate begins to
1) Voordrachten over Weefselleer, p. 271.
*) Analogous experiments were first made with oxyhaemoglobin but did not lead
to results of full worth, because during the forming of the equilibrium a portion
of this substance was converted into ils isomer methaemoglobin. Prof. PEKELHARING
then adyjsed me to continue the experiments with carbon monoxide-haemoglobin.
(977 )
form, the vapour pressure suddenly increases and then remains
constant until the salt is completely converted into the second hy-
drate. Similar sudden increases occur when a third or fourth
hydrate is formed. But totally different is the course of the vapour
pressure line in the case of carbon monoxide-haemoglobin; no dis-
continuities occur, the line commences with a nearly horizontal part,
turns at first the convex side downwards, acquires a point of inflec-
tion and at a still greater degree of imbibition it turns the coneave
side downwards ').
Afterwards I investigated the crystalline albumin from seeds of
Cucurbita Pepo, a globulin prepared in large quantities by Dr. G.
GrtsLer in 1881 by extraction with warm solutions of common
salt *). I was enabled to make use of a quantity of the substance
prepared by Dr. Grisivr personally; it consisted of beautifully
formed octahedral crystals and in other respects it also conformed
to the description given of it by Grisiur.
The method of the vapour pressure determinations in these and
further substances was the same as that followed in the ease of ihe
amorphous substances. The hygrometric line is shown in the illustra-
tion; it agrees in form with that of the carbon monoxide-haemoglobin.
As a third example I investigated the crystalline Bence Jones’s
albumose, which Miss A. tarurrerRInNK and Miss Worrvrrs pe GRaAaArr
have prepared from pathological human urine’). The substance used
for the research was kindly handed over to me by Miss GrurrErtnk ;
she had freed it, by washing with water and decantation, as much
as possible from ammonium sulphate. The substance consisted of
beautiful prismatic, presumably hexagonal crystals. Here also an
S-shaped line with a continuous course was obtained (see illustration).
Besides these three albuminous bodies, I also investigated a erys-
1) Hoppe Seyter and others (Schifer’s Textbook of Physiology I, p. 205) are
of opinion that a fundamental difference may be made between the water of imbibition
which is given off on drying at the temperature of the room and that retained
until the temperature reaches 115°C. The latter, represented in the hygrometric line
by the almost horizontal part, is called by them the “water of crystallisation”
of the substance. In my opinion there is no sufficient reason for such a funda-
mental distinction between the parts of a same continuous line. Moreover, the same
phenomenon is found in amorphous imbibing substances (even in cases of unlimited
imbibition power, such as serumalbumin and gum arabic) which are presumably
liquids of very greal viscosity and where there can be no question of water of
crystallisation. Even in these cases the substance dried at room temperature still
loses a little water when heated to 110°.
*) Journ. f. prakt. Ch. 23, p. 97—137.
5) Zeitschr. f. physiol. Chem. 34, p. 893—407,
(978 )
talline polysaccharide, amylodextrin, which had been prepared in two
different ways. The first specimen was made according to the method
proposed by NXcrrit') and agreed entirely with the deseription given
by that author of the substance; | am indebted for this substance to
Prof. H. P. Wusmax, who had it prepared for me by one of his
students under his supervision. The other sample was made according
to the directions given by Prof. Artuur Mrysr?) of Marburg and
had been kindly presented to me by that author for these experiments.
It still contained a trace of dextrin, but this was too trifling to be
able to cause any significant changes in the form of the hygrometric
line. As seen in the illustration, in both samples of amylodextrin an
S-shaped line having a continuous course was found®*). -
Summarizing: The form of the hygrometric line was determined
in the case of three erystaliine albuminous substances and one crystal-
line polysaccharide. This line had in all cases a continnous course,
showed nowhere discontinuities as is the case with inorganic salts
containing water of crystallisation, and had in all cases an S-shaped
form; the lines of the various substances strongly resembled each other.
And the remarkable fact appeared that the form of the hygrometric
line is the same in the case of swelling crystals as in that of imbibing
amorphous substances.
Comparison of swelling (imbibing) crystals with mixed erystais.
Let us now ask ourselves whether this behaviour is in harmony
with the hypothesis advanced that swelling should depend on the
formation of a solid solution of water in the imbibing body.
Solid solutions in the crystalline condition are called mixed crystals.
The said theory applied to swelling crystals therefore runs: Crystals
when swelling form mired crystals with water.
For our knowledge of mixed crystals we are chiefly indebted to
the researches of the physico-chemists during the last twenty-five
years. The pioneer work has been carried out chiefly by O. Leamann,
Rererrs, VAN ’t Horr and Bakuuis Roozesoom. And so numerous
1, Lieb, Ann. 173, p. 218—227 (1874); for the description of the crystals
see in particular p. 223. Also compare Brown and Morris Journ Chem. Soc. 55,
p. 449 (1889).
*) Untersuchungen tiber die StairkekGrner, Jena 1895.
5) 1 am still engaged upon a crystalline lipoide, protagon, and a crystalline
globulin, the edestin from hempseeds. The results will be communicated in the
more extensive publication.
a
=<
(979 )
has become the number of examples!) of substances which together
form mixed crystals that one is obliged to include the behaviour of
common substances such as quartz, inorganic salts and metals in
respect to water — where this miscibility in the solid state appears
to occur but rarely — in the cases where this miscibility is so
small that it readily escapes observation.
It is characteristic of a mixed crystal that it can take up, or lose,
a certain quantity of one of the components (such as water) the
crystal remaining homogeneous but also (what is closely connected
with this) that according to a continuous line the vapour pressure
of that component depends on the composition *).
As will be seen, the imbibing crystals behave exactly like mixed
crystals and even fall under the definition “mixed erystal” in my
opinion. Can this theory, however, also explain swelling, or enlarge-
ment by water absorption? Rererrs *) showed in 1889 that in the
case of mixed crystals the volume of the mixture at the first cont: ct
is equal to the sum of the volumes of the components. When
applied to the imbibition phenomenon this rule teaches us that when
a swelling crystal with a volume of 1 mm.* takes up 1 mm.* of
water — as is the case with the crystallised Bence Jones’ albumose
— the volume of the swollen crystal must be two mm.*; and
when the crystal remains homogeneous, all the length measure must
necessarily increase in size.
Finally, the question arises: but are there also known other sub-
stances, for instance some with a less elevated molecular weight,
which form mixed crystals with water? It is chiefly TamMann *) and
his pupil Lowensters who have found a series of examples thereof.
') A collection of a large number of examples is found at G. Bruni, Ueber feste
Lésungen, Aurens’ Sammlung chem. and chem. techn. Vortrage 1901 and F. M.
Jarcer, Zeitschr. f. Krystallographie 42, p. 286—276.
*) Usually this criterion is expressed in properties of the melling point line;
this, however, is closely connected with the vapour pressure line so that this
makes no vital difference.
8) Nernst, Theoretische Chemie, 2"¢ Ed., p. 121.
4) Wiedemann’s Ann. N. F. 63, p. 16—22 and Zeitschr. f. physikal. Chem. 27,
p 323—336. Tammann looks upon these crystals as solid mixtures of an anhydrous
zeolithe greup with a chemical combination of that group with water (a hydrate).
This explanation is not materially different from the one given here, but is only
less general. For every compound is in part dissociated and on the other hand, we
have serious reasons for believing that most of the mixtures of water with another
substance contain hydrate-molecules. The proof ‘that all the water is present as
hydrate-molecules is difficult to furnish and has not been given by Tammany. |
think, myself, it is safer to call them simply mixed crystals with water,
( 980 )
Tammann found the first cases in 1896 in magnesinm-platinous eyanide
and in a whole group of silicates (zeolithes). LOwenstPiN *) found
in 1909 a series of new examples: neutral oxalates, like those
of cerium, thorium, erbium, and lanthanum, strychnine sulphate and
basic zirconium oxalate (Zr (C,O,), . 2 Zr (OH), . aq.). In the course of
my investigations on swelling in 1907 I mnyself found new examples
in the flavone derivatives quercetin, quercitrin and sophorin.*) Quite
a series of examples is therefore, known and by a systematie search
this number is certain to increase rapidly *).
The hygrometric lines of four of these substances: quereitrin,
thorium oxalate, the zeolithe calcium chabasite, and basic zirconium
oxalate have been reproduced in the illustration for a comparison of
their form with those of the swelling crystals. The straight horizontal
initial part is in some of these substances considerably longer, in
others such as quercitrin and basic zirconium oxalate of nearly the
same order of magnitude as in the swelling crystals, but in principle
they have the same form: an S-shaped line which commences with
an almost horizontal part, turns the convex side downwards, then
at a still larger water content —
gels a point of inflection and
turns the concave side downwards ‘).
The behaviour of basic zirconium oxalate, which has been inves-
tigated by Lowenstein °), is particularly interesting. This substance
consists of pyramidal doubly-refracting erystals which are mixed
crystals with water and swell to double their size when placed over
a 5°/, solution of sulphuric acid under a glass bell jar; for instance
a crystal, whieh, when in equilibrium with a 30°/, sulphurie
acid (4 0.75), had a length of 17 scale-divisions, had a length of
o/
32 scale divisions after having been placed over a 5°/, sulphuric
1) Zeitschr. f anorgan. Chemie 63, p. 69—1389.
2) These experiments have not yet been published; this will happen shortly.
3) Such discoveries have, I think, a great significance for the criticism of the
water determinations in preparative, and particularly m organic, chemistry. For, the
habit of rounding off the analytical figures obtained in determinations of water of
crystallisation to whole figures seems no longer permissible. That the crystal
investigated is a hydrate of constant composition cannot be proved by the fact
that the analytical figure found is practically a whole number, but only by the
determination of the form of the hygrometric line, or that of the melting point line.
4) In order to save space in the reproduction, the lines shown in the illustra-
lion for ealeium chabasite and thorium oxalate are drawn only for values of 7 larger
than 0.20.
8) Loc ‘cit. p. 117.
( 981 )
acid ( = 0.96) for three days'). Just as Scuimper*) had found this
for the imbibing albumin crystals, the swelling takes place here
evenly in all directions so that the crystal form is retained.
Summarizing, we notice that there is so great a resemblance
between swelling crystals and mixed crystals that it is difficult to
draw a line of limit. If a crystal takes up another component to
form a mixed erystal, it will, according to Rererrs’ rule, increase
in size; if the quantity absorbed is small, the increase in size may
readily escape the notice of the observer, if large the crystal is seen
to “swell”.
The imbibition of crystals is, therefore, explained in an uncon-
strained manner and without any additional hypothesis by the theory
that the swelling depends on the formation of a solid solution. The
other theories of swelling met here with great difficulties.
Finally, I just wish to call attention to a fact which appears to
me particularly interesting from a physico-chemical point of view,
but the details of which are beyond the scope of this communication
so that I prefer to devote to it a special article. I allude to the
striking resemblance of the quantitative laws of the miscibility in
the liquid and in the crystalline condition, at least in regard to the
hygrometric lines. Compare, for instance the form of this line in
liquid sulphuric acid with that in crystalline basic zirconium oxalate
and in crystalline quercitrin (see illustration); the form is quite the
same. This explains the analogy found in the form of the hygrometric
lines of crystalline and amorphous swelling substances.
The experiments with haemoglobin were carried out in the Phy-
siologo-chemical Laboratory of the University of Utrecht (director
prof. C. A. Puxennarina), those with the other substances in the
Physico-chemical Laboratory of the University of Amsterdam (director
prof. H. W. Baknuis Roozesoom, afterwards prof. A. Smits).
1) Léweystemn observed that the crystals then become much softer and, finally,
even liquefied. The same thing | have found m haemoglobin and edestin crystals
which, at the imbibition maximum are so soft that they amalgamate when pressed
between two porcelain plates, whereas in the dry condition they are hard and
brittle. This fact is interesting in connection with the nature of liquid crystals:
here we notice that crystals which are not liquid lacquire this property conti-
nuously upon taking up a second component.
2) Zeitschr. f. Krystallographie, 1880.
( 982 )
Physiology. “On the Influence of lodoform, Chloroform, and
other substances dissoluble in fats, on phagocytosis.” By Prot.
Hampurerr, J. pb’ Haan, and Dr. I. BuBanovice. ’)
(Communicated in the meeting of January 28, 1911).
For the last 80 years Iodoform has been successfully applied in
the treatment of wounds and chronic inflammations. At first it was
thought that the favourable effect was based upon an antiseptic
action, but the idea was relinquished when it was found that lower
organisms amply develop themselves in a medium containing iodine.
Then other hypotheses were suggested which need not be dwelt
upon here?) They are mainly founded on lodine being split off.
None of these hypotheses, however, have proved to be generally
satisfactory.
For reasons which it is not necessary to state here, we have
raised the question whether the favourable effect of Todoform on
local infectious processes might be due, partly at least, to the stimu-
lating effect of this substance on phagocytosis.
The method of investigation adopted corresponded entirely with
that we followed when studying in our laboratory the effects of
other substances on phagocytosis. *)
I. Errect OF IODOFORM ON PHAGOCYTOSIS.
For this purpose a NaCl-solution of 0.9°/, was shaken with lodo-
form powder. Of the saturated Iodoform-solution thus obtained 3 eM*
were added to 0.2 cM* of a suspension of horse leucocytes in NaCl
sol Ooi.
At the same time a mixture was prepared of 0.3 cM* NaCl sol.
0.9°/, without lodoform and 0.2 eM’ of the same leucocyte suspension.
Both mixtures were left to themselves for 1‘/, hour, exposed for
10 minutes to the influence of 37°, carbon having been previously
added, and then cooled down. Finally microscopic preparations were
made and it was investigated what percentage of the total amount
of white blood corpuseles had taken up carbon. This was also done
with suspensions, which instead of 10 minutes, had been in contact
with earbon at 37° for 20 minutes, 30 minutes, 1 hour, 1’), hour.
Of the many series of experiments made, we subjoin some.
1) More explicit communications will appear elsewhere.
2) A discussion of these is found among others in Sroxvis—Zeenuizen’s Voor-
drachten over Geneesmiddelleer. 3rd Ed., 1906, Vol. 1, p. 399 and foll.
3) Hampurcer and Hexma. Proceedings of June 29th 1907, HamBurger u. DE
Haan. Biochem, Zeitschr. 24. 470, 1910; Cf.also Proceedings of June 9th 1910.
( 983.)
TAT BSE Ey or.
Effect of lodoform on phagocytosis.
| Percentage of leucocytes having
ite Guniae taken up carbon.
which the
leucocytes The leucocytes are
wereallowed Theleucocytesare in a saturated sol.
to take up iSace : of Iodoform in
carbon in Na Cl 0,9 lo NaCl 0.9 |,
(1 to 100.000) ')
: 1732) 25"
10 minutes Wh >< 100 = 40,8 Jy FN < 100 = 56,89,
| |
| 185 a | 205 _, The
20 “ | ag SAN Gi 967° 100 = 61,4 ,,
| 236 | 286 ;
2 in = » | r et
30 ss >< 100 = 53580",, | eS Sa 1
j “12
| 304__ e300 ip
| hour | m0) > (005250 ena >< 100 = 69:95,
| 402 , | 38t
4 . \Z nope aN sly /
11/, +, Se ID (ya eee UN TONY
597 ay
This table shows that after 10 minutes in the pure NaCl-sol. 0.9°/,
40.8°/, of the leucocytes had taken up carbon, but in the NaCl sol,
containing Lodoform 56.8 °/).
After 20 minutes the values are 54°/, and 61.4°/, respectively.
Hence it appears that Lodoforim promotes phagocytosis to a considerable
extent. After 1°/, hour the values are: 67.3°/, and 70.1 °/,.
We may infer from this that after that time the extent of phago-
cytosis has become about equal.
0
The same facts had been observed before when we studied the
effect of Calcium on phagocytosis. As we did then*) we may also
conclude now that the effect of lodoform is based upon an acceleration
of the amoeboid motion, and not upon a greater development of
activity (energy) of the phagocytes, rendering cells which under
normal circumstances would be too weak to take up particles, capable
of doing so by the presence of lodoform. For if this were the case
the phagocytosis would remain considerably lower in the pure NaCl
sol. than in the NaCl sol. containing lodoform. But after 1'/, hour
1) See page 986.
2) This means that of the 424 leucocytes counted, 173 had taken up carbon,
3) Proceedings June 9th 1910.
( 984 )
it has become about equal. Therefore it is only a question of acceleration
As we did formerly, we also investigated in this ease to what
extent phagocytes which had been left to themselves, exposed for
about 18 hours to a somewhat low room-temperature, and which
for the greater part seemed to have lost their phagocytarian power
as a consequence, could be stimulated again into taking up carbon-
particles under the influence of Todoform.
An answer is supplied by the following experiment.
TABLE II.
Effect of Iodoform on paralyzed phagocytes.
Time during Percentage of leucocytes, having
which the taken up carbon
leucocytes aa SS SS
were allowed| ; The leucocytes have
four | The leucocytes are been placed in a
o take up solution of lodoform
carbon par- placed in NaCl 0.99), in NaCl 0,9),
ticles (1: 100.000)
Te mn ee ‘| 202
fs our | 5X 100 = 38%) | 735X100 = 45,9/
It is seen that in a NaCl sol. 0.9"/, the phagocytarian capacity
fell to 3.8°/,, but rose again to 45.9°/, when the pure NaCl solution
was replaced by one containing Iodoform.
In what concentration does Iodoform exercise a still
perceptible influence ?
To answer this question lodoform solutions of different concen-
trations were prepared. For this purpose we started from a saturated
Iodoform solution') diluting if with 5-, 10-, 20- and 50-times the
amount of NaCl-solution.
In these solutions the extent of phagocytosis was determined in
the usual manner. It need only be observed that the white blood
corpuscles were allowed 85 minutes to take up carbon.
The following table HI will be clear without farther explanation.
This table shows that whilst in NaCl of 0,9°/, the phagocytosis
amounted to 44°/,, it had risen to 59°/, in the saturated Todoform
solution (0.001 °/, lodoform or I upon to 100.000). This is already
a confirmation of the results mentioned in the preceding tables.
1) A saturated solution of lodoform in NaCl-sol. 0.9 °/) contains about 0.001 °/,
CHI;. We shall revert to this on p. 986.
(985 )
(AGB EB) Il:
Concentration of lodoform-solution in which the effect
on phagocytosis is still perceptible.
F | Percentage of leucocytes,
ALLIS having taken up carbon.
\ Tag he a
NaCl 0,9 %p!)
ay
( eX 100 a7,
291
\ Far US
1 lodoform to } ea
100,000 NaCl 0,9 °/, 996
aoe >< 100 — 5349 ‘
1 lodoform to ‘ Bane
50,000 NaCl 0,9, 371 © 100 = O14,
1 lodoform to
1,000,000 NaCl0,9%o 205 >< C0 aC
— 100 = 529
298 ae
| Iodoform to
2,000,000 NaCl 0,9 04,
2
ID Dk KUO) seta tay
1 lodoform to — 100 = 46,9
5,0L0,000 NaCl 0,99), \ oa * ee
or <
1 gr. molecule CHI, to } 176
1,900,000 Litres NaCl 0.99/, ang OX 100 = 47,3
But also in an Todoforin-solution 20 times as weak, a considerable
increase is visible, and it may even be perceived in a 50 fold dilution.
In this solution we can no longer distinguish the lodoform by the
smell.
These results were fully confirmed by experiments with leucocytes
which had been left to themselves for about 18 hours. We learn
this from the following table.
1) We give .here parallel experiments which illustrate the exactitude of the
method of investigation. As a matter of course parallel experiments have been
rade in all cases, but it has mostly been thought sufficient to give the average
of the results.
( 986 )
TaAS bla lV.
Concentration of the lodoform-solution in which the effect
on phagocytosis is still perceptible.
The leucocytes had been placed for about 18 hours
in NaCl-sol. of 0.9%).
he | Percentage of leucocytes,
Fluids. which have taken up carbon.
Na Cl 0,99, | ae Dae 100 = 11,3%
4s
1 Iodoform to 100,000 Na Cl 28 “x 100 = 44,2 ,,
0.9"/) (Saturated Iodof.-sol.) 3
o.
1 lodoform to < 100 = 41,3
509.000 Na Cl 0.9"), TOY
RD
1 lodoform to ee IO ee HT
4000,000 Na Cl 0.99/, 88
95,
1 lodoform to 225 < 100 = 46,8 ,,
2000.000 Na Cl 0.99/, 480
1 Iodof. to 500.000 Na C1 0.9" 5 db ;
(saturated Iodof.-sol. 50 times 43a 7S 100 = 34,9 ,,
diluted)
It is seen that in a NaCl-solution of 0,9 °/, the phagocytosis amounts
to 11,8°/,; in the saturated lodoform-solution 44,2 "/,, and in the
50 fold dilution still 31,9 °/,.
So it appears that in es) strony dilution lodoform is still able to
awaken the phagocytes from their slight mobility.
How much lodotorm is found in this fluid ?
No data are extant, as far as we know, as to the solubility of
lodoform in water or in NaCl-solution. Therefore we had to make
some experiments ourselves. This was done by two methods.
In the first place the clear well filtrated lodoform-solution was exposed to the
light for a considerable time, till the Iodoform smell was no longer observable,
and was then treated with concentrated nitric acid. The fluid thus obtained was
shaken with chloroform, which caused the iodine to pass into this fluid, and to
colour it red. By the side of this Nal-solutions of known concentration were treated
with HNO. and afterwards with Chloroform.
Finally it was investigated what concentration of a Nal-solution gave the same
colour intensity to the chloroform as the lodoform-solution under examination.
From these experiments it appeared that in the saturated solution
of Iodoform in NaCl 0.9°/, was found 0.001°/, Iodoform.
The other method which consisted in the Iodoform, split off under
( 987.)
the influence of HNO,, being titrated with the aid of Na,S,O, and
KMnQO,, gave almost identical results: a concentration of 0.00109°/,.
So that we may say that even in a concentration of 1 to 5.000.000
or, in other words, in a solution of 1 gr. molecule CHT, to 1.905.000
litres water, lodoform accelerates phagocytosis to a considerable extent.
The experiments in table IV leave no doubt but that the dilution
may be carried on still further.
How does lodoform efject an acceleration of phagocytosis °
In the first place we proposed to ourselves the question whether
it might be perhaps traces of iodine which, though present only as
ions, had this stimulating effect. Against this view pleaded already
former experiments on the comparative effect of NaCl, NaBr, and
Nal, which has shown that the ion of iodine weakens phagocytosis
to a considerable extent. *)
Another objection to this view was furnished by the experiments
with an iodoform solution which had been exposed to the light for
TAME wee AV.
lodoform solution the composition of which has been
modified by the influence of diffuse daylight
| Percentage of leucocytes having taken up
Time during Carbon
which the
phagocytes de Mele ih
poise allowed The leucocytes are phe asics
otake Oop | . STOUT iodoform
carbon. | in NaCl 0.9% solution.
- 15 Ee 3 :
10 minutes =e 100 = 96,7/, x 100 = 15,49 ,,
430 430
S 121 a 128 :
20 ” <100=27 , | —->x<7100 = 25 >
474 B12
a 189 128 ‘
30 ” —= 100 = 40:6", | —— K100 =34 7
| 465 512
| 287 163
1 hour | —5¢100=6!,7, | —-x100=364,
4GD 447
|
rr | 329 be = | 125
2» == LUD —= 56,95 =a X< 100 = 39,8 »
578 | 314
1) Hampurcer und De Haan. Biochem. Zeitschr. 24, 304, 1910.
( 988 )
a short time. Jodine was not in the solution, but iodine as ions was,
probably as HI. For iodine as such could not be shaken out with
the help of chloroform only, this however could be done when at
the same time HNO, was added.
Well then, this iodoform solution, exposed to the light, was not
only unable to promote phagocytosis but greatly impeded it.
This may appear from the table VY.
We see that in the NaCl-solution containing iodoform the phago-
cytosis always remains below that in the pure NaCl-solution. We
see for instance that after 10 minutes the phagocytosis in a pure
NaCl solution amounts to 26.7 °/,, but in a NaCl-solution containing
iodoform only to 15.4°/,.
After 1'/, hour the values are 56.9°/, and 39.8°/,.
The following experiment for which, besides the (old) iodoform-
solution which had been exposed to the light, also a fresh one had
been taken, confirms the result.
TeASB es Es evr
Comparison between a fresh iodoform-solution and
an old one (one somewhat decomposed by the light).
Time during Percentage op leucocytes having taken up
: carbon.
which the me ee
leucocytes The 1 t
eee once ne leucocytes are
pees The leucocytes are | an aleafandted
o take up | |
P | in Na Cl 0,90 iodoform
carbon. | aoa Oars: solution.
: | 108 ort 126 ae
| — 955.0 = == 34.80
10 minutes | 077° 100' = 26;59/, 360°° 100 == 34,8 9/,
99 219
aA) y Spee = S058 : 4h? 100 = 49:7
: | 268 Rece 4A =a
30 qo 100 — 36,6 0 eas 100: 52;555,
91
319 ><1100'=;26;523,,
(old Iodoformsol.)
230 : ee 278 oe
1 hour | pair 100 = 54,2 ,, 798° 100 = 53,8 ,,
; | 248 ee 214 ae
WES © oss — <1 00535015) 37976 00 —9%3 =
( 989 )
Our views were moreover confirmed by an experiment, tending
tu investigate to what extent the phagocytosis could be revived in
an 18 hour old leucocyte suspension by the iodoform-solution which
had been exposed to the light. In the same experiment the effect of
the fresh iodoform-solution was ascertained and also that of chloride
of calcium.
At the same time the effect was investigated of a NaCl-solution,
containing a slighter amount of the old iodoform, and which had
been obtained by diluting the old saturated iodoform solution with
double the volume of a NaCl-solution. This experiment we resolved
upon with a view to the consideration that if the old iodoform
solution contained a noxious substance it would make itself less felt,
if this solution were diluted. Under these circumstances, the favour-
able effect of that iodoform in the solution, which had not been
decomposed, would more plainly manifest itself.
i AS Bee EF VII.
Effect of fresh and old iodoform-solutions and of CaCl, on
the almost paralyzed leucocytes.
ae Percentage of leucocytes
ELC having taken up carbon.
19
NaCl 0,9 /o 61 x 100 = Ay,
Ww)
Fresh saturated solu- Ee
tion of lodoform in oor. LATE Ts
NaCl 00,99, 976 >-< 100 = 15,6 »
(0.001' , CHL) |
Old saturated solution ; 0
of lodoform in =< L000)
NaCl 0,9 624
| vol. of the old saturated
solution of Iodoform in =
NaCl 0,99) and 2 vol.
NaCl 0,9", SUA
((.00039/,, CH.)
x 100 = 127, ”
i 0.9°/ 83 ww)
Ne ,080), CaCl ly < 100 = 16,4
”
——
We see from this experiment:
1. that the phagocytosis in the old leucoeyte suspension has fallen
to about 4°/,;
2. that the fresh iodoform solution raises the phagocytarian power
again to 15.6"/,, but that
65
Proceedings Royal Acad. Amsterdam. Vol. XIIL.
( 990.)
3. in the old iodoform solution the phagocytosis amounts to nothing,
whereas in a solution, which contains only one third of the old
iodoform solution, it has increased to 12.7°/,.
From these experiments it may be concluded (hat not the ton of
iodine but Lodoform as such, causes the increased phagecytarian
power.
And now the question suggests itself: how can the favourable
effect. of iodoform upon the rapidity of the phagoeytarian process
he explained ¥
We must obviously think here of a decrease im the sur face-tension
which facilitates the amoeboid motions of the protoplasm.
lt is not diftieult to account for this decreased surface-tension if
we consider that 1odoform is soluble in fat substances and that, as
may be concluded from numerous investigations, the outer layer of
cells consists of a fat substance, a so called lipoid membrane.
Further it is obvious that such a lipoid membrane will grow more
flexible after having absorbed iodoform, in other words that the
surface tension will decrease, and that consequently the amoeboid
motion will be facilitated.
If this interpretation was the correct one, then it might be expected
thet also other substances, which are soluble in fat, such as chloro-
form, Benzene, Camphor, would affect phagocytosis in a similar way.
As will appear from the following experiments, this was indeed
the case.
2. Errect or CHLOROFORM ON PHAGOCYTOSIS.
It might be expected that, besides an accelerating effect by weaken-
ing the outward lipoid layer, chloroform would have a paralyzing
effect, opposed to the former, viz. on the protoplasm of the phagocytes.
Therefore various dilutions had to be tried.
Soon it was found that dilutions of 1 to 2000, 1 to 6000 and
also 1 to 10000 impair phagocytosis. The following table VIII con-
tains some experiments with weaker dilutions.
From this table it appears that chloroform 1: 20000 raises the
phagocytarian power from 40.9°/, to 50.4°/,, further that phagocytosis
is considerably increased by chloroform 1: 100000; there it rises
to 60.5 °,/,.
Evidently in the chloroform-solution 1 to 20000 the above men-
tioned paralyzing influence also makes itself felt.
In a dilution of 1:500.000 the favourable effect remains, to about
he same extent as in 1: 100.000, and finally in a solution of 1
we
(991 )
iA BLE VIII.
Concentration of the chloroform-solutions in which the
effect upon phagocytes can be observed.
Percentage of leucocytes
Fluids. having taken up carbon.
174 :
pa X 100 = 40,6 %
Na Cl 0,9 {|
| 938 .
=g9 7% 100 = 2,
chloroform 1 : 20.600
220
iA 100 p40 oe
Q54
519 x< 100 = 60,6 3
—
chloroform 1 : 100,000
382 . :
155 <1100' 60M"
——=-
33° Se 100 = 57
sen 7 as
chloroform 41 = 500,000
219
Ta < 100 = 59,1 ,,
379 fein
268 S<1007— 43,6 "3
Rb
chloroform 1 : 5000,000
298
100 —= 45
661 7° cae
chloroform to 5.000.000 NaCl-solution this favourable effeet is_ still
visible, it is true, but it is very slight.
The following experiment, made only with solutions of chloroform
of L to 500,000, but this time with diferent periods of contact
between carbon and leucoeyte-suspensions confirms what has been
said above.
We see from this table that already after 50 minutes the accele-
ration of phagocytosis, effected by chloroform, has manifested itself
at its maximum value. After an hour it still exists, bat in a slight
degree. The figure 27.5, with the note of interrogation, must be owing to
a mistake in the concentration of the solution. Indeed other prepa-
rations of the same suspension gave after an action of 45 minutes
65%
( 992 )
TAB LEAL
Influence of Chloroform on phagocytosis.
F 3 Percentage of leucocytes having
Dine -dunns taken up carbon.
which the
phagocytes a ms
3 tlowed| The leucocytes are The leucocytes are
co owe e leucocytes < a aneOlihiontGn
to take up vol. chlorof to
i 210,99 Ray thoy :
carbon. in NaCl 0,90/,. 50,000 NaCl 0,9),
: 64 _ | 400 oe.
10 minutes aoe <100=19 %/% ana 100 = 95,90/9),
WO on
166 my 5 180 Paes
20) ” Figen ” XK 100 = 30,3 ”
foo tod
215 a 269 | = ee
20 a reas 100 = 402 ,, 591 < 100 = 51,6 ,
P 330 ee 106 on
KD 4 Ho 76 100 = 45,0 , 3a 76 0 == 2h aie
424 OO.
345 eesae 323 ‘poe saae
{ hour = —— aie 15k
63976 pany 50378 a
likewise much too low a figure. A mistake in counting is therefore
not to be thought of.
We now revert to the question, to what exteut the leucocytes
which have been placed during a night in a solution of NaCl 0.9.°/,
and which consequently have lost partly or entirely their phagocy-
tarian capacity can be revived again by an addition of chloroform.
To this series of experiments has been added one with lodoform
and one with CaCl?, as we wished to investigate to what extent the
stimulating effect of these substances corresponded with that of
chloroform.
The table shows that if phagocytes which have been left exposed
during one night to a low room-temperature, are acted upon for
y Chloroform in a concentration 1: 500.000, whilst the
suspension is afterwards brought into contact for 15 minutes with
carbon at 387°, the Phagocytosis will be raised from 8,7 to 11.1°/,.
If we give more time to the suspension to take up carbon viz. 30
minutes, then the favourable effect of chloroform makes itself more
Injurious,
I'/, hour by
plainly felt, the phagocytosis rising from 20 to 34.2°,.
however, the effect of chloroform proves to be at a contact of the
phagocytes with carbon during 45 minutes; perhaps the cells, which
0 E—E———EEEEeEeEOEOEOeeeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeE ee ee
( 993
TAU Brak, ox.
Effect of Chloroform on phagocytosis.
The leucocytes have been exposed for about 18 hours to a Na Cl-solution of 1," 9,
Time during which the Percentage of the leuco-
phagocytes were allowed Fluids, cytes having taken up
to take up carbon. carbon,
AD eo
NaCl sol. 0,9°/, ay S< 100 = 8,79),
15 minutes
1 vol. Chlorof. to 500,000 60 i
Na Cl sol. 0;9°/) >40 x es! ae 11,1 ”
108
Na Cl sol. 0.9"/, er 0)
208
1! Chlorof. to 500,000 Na Cl 213 anther,
| sol. 0,9"), aC ee
30 5 |
: 144
Na Cl 0,9°/) ++ 0,001°/, Todof. | 10 S00 Saale
AN
: an 117
Na Cl 0,99, + 0,05°/, CaCl, 559 XX 100 = Ab,4 ,,
Na Cl 0,9° aes 100 20.3
\ a PUY) 609 7* —= sl) yy
19 ” H
| Chlorof. to 500,000 NaCl o7 a
| sol of 0,9%, 298 >< 100% 25s,
have been weakened already, are further impaired by the longer
37°
exposure to 37°, in the presence of chloroform. For this supposition
there is a good deal of reason, seeing that longer heating at 37°
begins to have an injurious effect even im a pure NaCl solution.
As we see from the table the stimulating effect of lodoform is about
equal to that of Chloroform.
To a much more considerable extent than these two, however,
Calcium stimulates the phagocytes in these experiments.
3. Errect OF BENZENE ON PHAGOCYTOSIS.
Of Benzene (C,H,) the following concentrations in a NaCl-solution
of 0,9°/, were made:
1 Vol. to 5000, 1 to 10,000, 1 to 500,000 and 1 to 5,000,000.
The fluid acted upon the suspensions during an hour; then they were
bigse)
brought into contact with carbon for 80° minutes at 37
( 994 )
DyAV BASES Al,
Concentration of the Benzene-solution in which the effect on
phagocytosis is still perceptible.
Percentage of the leucocytes
having taken up carbon
Fluids.
266
— AKO)
\ 642 Ne
NaCl 0,5
164
>< 100 = AQ,D »
AOD
Sr 100 = 50,2 Ss
Benzene | : 5000
= 100 5 0
Benzene 1: 100,000
E | 373
758 x 100 — 1,2 ”»
276 We
478 x 100 = ty! »
Benzene 4: 500,000
982
| 166 >< 100) == 16055
5
ar SS OW EN
Benzene 1 : S0Q0000
\
|
This table leaves no doubt but Benzene too revives phagocytosis.
This is visible at a dilution of 1 to 5000, but the effect is found to
be much greater at a dilution of 1 to 500,000.
Very likely the cause of this difference will have to be traced to
the narcotic influence of benzene. At. a dilution of 1 to 5000 Overron
saw tadpoles pass into narcosis.
These experiments were repeated with leucocytes which had been
placed during one night in a NaCl-solution 0,9 °/,.
Still more clearly than in the preceding table we can observe
here the stimulating effect of Benzene. The most favourable proportion
is again 1 to 500.000, but a still greater effect is obtained by CaCl,,
at least in the concentration given.
\ $a eine
a
(995 )
TAB EE, XI
Effect of Benzene on phagocytosis with leucocytes which had
been placed for about 18 hours in a NaCl-solution of 0,9" 9.
bik Percentage of the leucocytes
Fluids. having taken up carbon.
83
| | GD XK 100 = 17,8%,
} A405
NaCl 0,9) Wal aes
| 19
: 100 = 18,3
| 410 x a9)
|
106 he
7 100 = 2957 is
Benzene 1 : 5000
195 Be
G29 100 = 31,3 ”
11 ae
19% SO BE
Benzene ! : 100,000
00
x 100 = 23,2 ”
854
147 Aas
Benzene 1:500,000 «
Da
] 159 2 100 = 355 ,
\ 102
{ 92
= g —— {C0 fa
| FEN 100 = 19,2 ,
Benzene 1:5,000,000 (
46
| 199 xX 100 = 20,7 ,
: 153 t bi
CaCl, 0,05 % 10 >< 100) == "3733",
4. Errecr oF CAMPHOR ON PHAGOCYTOSIS.
We examined a saturated solution ') of Camphor in NaCl 09°),
and diluted this solution 5 and 25 times.
In all these fluids the smell was still distinctly noticeable.
After having been brought into contact for an hour at the normal
temperature with these fluids, the leucocytes were brought into contact
with carbon and left to themselves for 80 minutes at 37°, as usual.
1) As we know the solubility in water is very slight.
(996 )
The following table contains the results of the first series of
experiments,
Tea BiB xi;
Effect of Champhor on phagocytosis.
es Percentage of leucocytes having
SIE taken up carbon.
273
Na Cl 0,9, a >< 100 40,69),
Saturated Camphor-solution 284 nt
in NaCl 0,9°/, Tease 2,5 ,,
Saturated Camphor-solution | 218 ce
diluted 5 times =50 ><1100, = 50a;
Saturated Camphor-solution | 287 ene
diluted 25 times. | § 2 gi3.7 ee ae
It appears from this table that in a saturated Cainphor-solution
the phagocytosis has increased, likewise when it ts dihited with 5
or 25 times its volume of water.
As in the preceding experiments Camphor was also tried as a
means of reviving leucocytes weakened by an 18 hour’s stay in a
NaCl-solution of 0.9 °/,.
iA BLE, XIV.
Effect of Camphor on phagocytosis with leucocytes which had
been placed for about 18 hours in a NaCl-solution 0.9").
Binds Percentage of leucocytes
3 having taken up carbon.
38
NaCl 0,9"/0 Soy 2X 100 = 11,8%0
0
Saturated Camphor-solution | O85 > 00l— ae
Saturated Camphor-solution 4 ay ie
diluted 5 times. 549 76 10 = Ate
Saturated Camphor-solution : ines
diluted 25 times. 29, x 100 = Wy yy
NaCl 0,9°/ + 0,059/, CaCl, TO 100 = 428 ,
(997 )
We see from these experiments that the saturated Camphor-solution,
instead of reviving the phayocytarian power, has entirely destroyed Ut.
The red blood corpuscles when seen under the microscope have lost
their colour and from a number of white ones the contents have
passed out.
This it is true could not be observed in the case of the weaker
Camphor-solutions, but yet there can be no difficulty in assuming
that in these too the phagocytes have suffered, whence no revived
phagocytosis took place.
The reason why in the preceding series of experiments the phago-
cytosis was promoted by Camphor will have to be sought in the
fact that in the first case fresh cells were experimented upon, in the
second case phagocytes weakened by their long stay in NaCl-solution
0,9°/,. Indeed they must have lost ions of Ca and probably also
other ions by interchanging them with Na.
That their life has not been destroyed for ever is seen from the
fact that an addition of CaCl, raises the phagoecytarian power again
to 42,8 °/,.
There were obvious reasons for repeating the experiment also with
weaker Camphor-solutions. Therefore we took a saturated Camphor-
solution in NaCl 0,9°/,, diluted it with 1O0-, 50-, LOO- and 500 times
its volume of NaCl 0,9°/,. For the rest the method of experimenting
was entirely the same as that followed in the preceding series of
experiments.
TAS BALE XV:
Concentration of the Camphor solution in Na Cl 0,5°/, at
which its effect on phagocytosis is still perceptible.
nae Percentage of leucocytes having
LGR taken up carbon.
46 =
Na Cl 0,90 0 = < 100 41,7 Oj,
3a)
| IS8
Camphor 1 : 10 a SSO) SID.
OU
132 ;
Camphor 1 : 50 aan x< 100 0,2 ,,
32s
DAD a
Camphor 4 : 100 —— << 100 55,£ ,,
bet
196.
Camphor 1 : 501) aah >< 100 = 491 ,,
( 998 )
From this series of experiments it may be concluded that a saturated
camphor-solution in a 500-fold dilation still revives phagocytosis.
5. Som ADDITIONAL RiEMARks.
From a survey of the various experiments detailed above it appears
that all substances, hitherto experimented upon which dissolve in fat
or are soluble in fat, promote phagocytosis to a considerable extent.
And we may add that this was also the case with chloral (1 to
20.000 and weaker) and with turpentine (1:50.000), rwhich latter
result, it may be observed by the way, one will be inclined to connect
with the power of turpentine to cause local exsudations, and also
with the therapeutic inhalation of turpentine-vapour at tuberculous
processes in the respiratory organs, and the stimulating effect of the
smell of resin.
The results we obtained with phagocytes show a remarkable
correspondence with what J. Lorn, and afterwards R.S. Linum, have
observed on the artificial parthenogenesis of eggs‘).
Lore discovered namely that substances dissolving fat have the power
to render the parthenogenetic development of eggs possible.
How can this fact be explained? We may imagine with Lors
that the substance dissolving the lipoid, weakens the egg membrane
thus giving rise to the formation of a fertilizing membrane. We
think we may safely go one step further, and assume that it 1s
owing to the weakening of the membrane that the movement of the
protoplasm, underlying the cell-division, manifests itself. This view
is confirmed by the observation of R. 5. Linum *), who saw that
also by a short transitory raising of the temperature in eggs of star-
fishes a typical fertilizmg” membrane may be formed, which formation
is followed by the development of part of the eggs into larvae.
J. Lore could confirm this as regards the jelly-fish.
There is sull more analogy between what has been observed about
phagocytes and about eggs. If we allowed more concentrated solutions
of Chloroform, Benzene, Camphor, ete. to act upon the phagocytes
they caused a decrease in the phagocytosis; in the case of Camphor
the cells were even destroyed. Well, Lore has found that a somewhat
protracted action on eggs of fat-dissolving substances causes destrue-
tion of these cells, so-called cytolysis.
Consequently the favourable effect which the above-mentioned sub-
1) Gf. aco. J Loes. Die kiinstliche Parthenogese. Handbuch der Biochemie des
Tiere. Band | 1910. p.p. 101 en 102.
2) Ro S. Lintiz. Journal of Experim. Zoology 5, 1908. 375. (cited from Loes l.c.).
Menschen und der
( 999 )
stances (which are all soluble in fat) have on the mobility of phago-
cytes and on the development of eggs may be regarded from the same
point of view.
But there is still more made clear by the above researches. It is
namely a well-known fact that various narcotics applied in smaller
doses have a stimulating effect and paralyze in greater quantities.
ENGELMANN observed this already many years ago on vibratile cilia
and also as regards the nervous system we know of Chloroform,
Alcohol, Aether that when first adininistered, that is to say when
they have entered into the nerve-cells in small quantities, they cause
excitement, but produce insensibility when a greater amount of the
substance has penetrated into the cells. As far as we know this
contrast has never been explained, but when viewed in connection
with our experiments the phenomenon becomes clear.
Two factors must be distinguished in the working of the narcotic:
in the first place it must be dissolved in the lipoid membrane,
secondly after having entered into the protoplasm in — sufficient
quantities it will produce its narcotic effect. But already before the
latter has taken place the lipoid membrane has undergone a decrease
in its surface tension and the stimulating effect manifests itself. The
excitement disappears of course when the protoplasm has been
paralysed ').
Hence we see that what was observed about phagocytosis deserves
ves our attention also from a general point of view. We «do not
mean to say, and this must be distinctly understood, that all sub-
stances dissolving fat have the same effect on various cells; far from it.
In the first place the word “lipoid? is a collective notion, and it
may be expected that with different cells the composition of lipoid
will be quite different, and also its solubility in one and the same
fat-dissolving substance. Secondly not all substances penetrating
into cells, dissolve fat or can be mixed with it. Urea may serve as
an instance.
And thirdly, it need hardly be observed that the power of asub-
slance fo penetrate through the lipoid membrane will by no means
determine its further physiological and pharmacological effect. This
will be chiefly dependent on the chemical structure of the cell-con-
tents, which are different in the different kinds of cells.
1) The paralyzing effect of narcotics on protoplasm Maneretp is inclined to
attribute to want of oxygen, caused by the decreased permeability of the cellipoids
to this gas. (Priucer’s Archiy. 131, 1910, p. 464.
( 1000.)
These remarks have been already confirmed by what we observed.
In eges of sea-urchins and star fishes an artificial membrane-forma-
tion could be effeeted according to investigations of J. Lone by the
addition of slight quantities of digitaline. Yet it was impossible to
discover an acceleration’ of phagocytosis with this substance, nor
with Strophantine.
Nevertheless it will be useful to investigate to what extent the
facts observed by us hold good for other cells than those mentioned,
and also for other substances which dissolve fat.
Hence we are continuing our investigation in this direction, and
have already arrived at the preliminary conclusion that the move-
ment of spermatozoa is promoted by diluted solutions of turpentine.
We could not effect this by means of lodoform, perhaps because
this substance, in the concentration necessary to increase the mobility,
had a deleterious effect upon the living protoplasm.
SUMMARY.
The above investigations have mainly led to the following results:
lL. A saturated solution (0.001 °/,) of Lodoform in a NaCl-solution
of 0,9°/, is able to accelerate phagocytosis to a very considerable
evtent. This favourable effeet of lodoform not only manifests
itself in the case of phagocytes which have been obtained from
blood a short time before, but also in the case of those which
have for the greater part seemingly lost their phagocytarian power,
having been placed for a considerable time, e.g. 18 hours, in a
NaCl-solution of 0,9 °/,.
2° The effect of Llodoform is still plainly visible in a fluid containing
1 gramme CHI, to 5.000000 eM’. NaCl-solution 0,9 °/, or 1 gramme
molecule CHI, to 1.900000 L of the NaCl-solution.
Undoubtedly the effeet will be visible in a still stronger dilution.
(Compare Table LV).
3. This effect of an Llodoform-solution cannot be ascribed to ions of
I, for these are found to impede phagocytosis. We must think
here of the property of Lodoform to dissolve in the fatty outer
layer of phagocytes ‘the so-called lipoid membrane) ; hence the
membrane is softened, the surface-tension diminishes and the motion
') Artowe. Article: Chloroforme, in Richet’s Dictionaire de Physiologie.
( 1001.)
of the phagocytes is made easier. A amore rapid haking up of
carbon particles must be the consequence Of this.
[7 this interpretation is the correct one, then other substances,
soluble in fat, must also be able to effect an accelerated phago-
cytosis. This result was indeed arrived at for all substances of
various composition experimented upon, viz. Chloroform, Chloral
senzene, Camphor and Turpentine.
Chloroform was seen to promote phagocytosis even im a concen-
tration of 1 to 5.000000. In a concentration 1 vol. to 500.000
the increase of phagocytosis amounted to 43°/,. In- stronger
solutions this value was smaller and the stronger the solution
the more the accelerating effect diminished. This must be attri-
buted to a second factor coming into play, viz. paralysis of the
protoplasm-motion, which factor manifests itself but little in a
very weak solution.
Benzene e. g. was found fo have the most favourable effect on
fo)
phagocytosis in a dilution of 1 ta 100.000.
A saturated solution of Camphor in NaCl-solution of 0,9 °/, caused
a fairly considerable increase of phagocytosis. But if this saturated
solution was diluted with LOO times its volume of NaCl-solution
then the acceleration was again more considerable viz. 32 °/,.
Turpentine in a dilution of 1 : 100.000— effected an increase
of phagocytosis of 24.7 °/). but in a solution of 1 to 25.000
instead of an increase it caused a decrease and that of more
than 80°)! With Ch/oral the results were exactly the same.
The facts mentioned in 1—8 deserve our attention from two
points of view:
a. They correspond entirely with those observed by J. Lore in
the artificial fertilization cf the eggs of the sea urchin (echinus)
and the star fish. By allowing namely substances dissolving fat
to act upon these eggs he could effect the development of these
into larvae.
In our opinion the explanation of this fact must be sought in
the circumstance that by the weakening of tae lipoid egg-mem-
brane the protoplasm-motion on which the division-process is
based, is facilitated or rendered possible. This agrees with the
observation of R. oS. Lintin that the mere warming of the eggs
( 1002 )
may bring about the division, a fact which was confirmed by
J. Lorn.
The analogy between the effect of substances dissolving fat on
the development of eggs on the one hand, and on the aecelera-
tion of phagocytosis on the other, may be carried on still further,
if we bear in mind that a copious action of these substances
causes paralysis in the phagocytes (ov destruction, as with eam-
phor) and cytolysis in the eges.
4. It is a well-known fact that narcotics stimulate when applied
in small quantities and only paralyse in greater amounts. Viewed
in the light of the facts we have observed about phagoeytes, the
explanation is easy to. find.
At first, namely, the lipoid membrane of the cells is weakened,
consequently the surface-tension grows less, and the rapidity of
motion, the activity becomes greater. As soon as a greater amount
of the nareotic has entered, its paralyzing effect on protoplasm
becomes manifest.
For some general considerations see p. 998 and foll.
Groningen, January 1911.
Physiology. — “On the stimulating effect of Chloride of Caleium
and of intestinal mucous membrane extract on the action of
Trypsin.” By Mr. KE. Hrxkma. (Communicated by Prof. H. J.
HAMBURGER).
(Com nunicated of the meeting of February 25, 1911),
The investigation reported on in the following pages found its
starting-point in an investigation relating to the question whether
chloride of calcium possesses the property of activating trypsinogen.
Several investigators, particularly LarGuier pes BANcELs'), DELEzENNE?*),
Zvxz*) and recently also miss Ayrton’) have attributed to calcium
‘) Laraurer pus Bancets. C. R. Soc. de Biol. 1895, p. 130.
*) Detezenne. C. R. Soc. de Biol. 1905, p. 476, 523, 614; 1906, p. L070;
1907, p. 274.
‘) Zunz. Annal. de la Soc. Roy. des Sc. Méd. et Nat. de Bruxelles. XVI. 1907.
*) Miss B. Ayrron. Collected Papers. Inst. of Physiol. University College London,
Vol. XV. Edited by E. H. Sraruine.
’
ee
—
( L003.)
salis, and also to some other salts, the faculty of rendering inactive
pancreatic-juice, or pancreatic extract, active with respect to albumen,
in other words, capable of activating trypsinogen.
During the last few months [T too have made a number of
experiments with a view to obtaining, if possible by an independ-
ent investigation, a confirmation of the results arrived at by these
authors, whose conelusions are for the rest pretty well identical. I
became aware that an investigation as to the activating effeet of
chloride of calcium on trypsinogen (I have not as yet extended my
investigation to other salts) though apparently simple, was attended
with considerable difficulties. Hence my experiments on the subjeet
have not yet led to any definite result so far as the activating effect
of chlorid of caleium on trypsimogen is concerned. But in the course
of this investigation some other facts have come to light which
seem to me to be worth publishing, the more so as the difficulties
encountered, will be to some extent set forth and explained by them.
In the course of the above-mentioned investigation it was namely
discovered that chloride of calcium tas the property of materially
stimulating the action of trypsin, when already active in itself
and free from irypsinogen. The same fact was observed about intes-
tinal mucous membrane extracts, but in a much slighter degree.
There is no need to point out that activating trypsinogen (i. e.
transforming inactive trypsinogen into active trypsin) and stimulating
the action of trypsin (i. e. stimulating into greater activity the ferment
when free from ftrypsinogen and already active as it is) are two
entirely different notions.
It has already been said that a further investigation relating
to this stimulating action was begun on account of observations
made in some experiments, which were carried out to study the
activating effect of chloride of calcium on trypsinogen. We subjoin
some of the experiments made. (Tables | and Il). Beforehand it
must be mentioned that the panereatic-juice experimented with, was
obtained by pressing out a pig's pancreas, likewise that the extracts
from the intestinal muccus membrane were prepared by extracting
the seraped-off intestinal mucous membrane, and filtvating it after
some time. Further that in all the experiments discussed in this
paper, we used for albumen: coagulated white of hens’ eges, accord-
ing to Mwrr’s well tried method, and finally that wherever in this
composition chloride of calcium is spoken of, the salt without water
is meant.
From the experiment detailed in Table 1 we may draw the fol-
lowing conclusions :
( 1004)
erat AS Ls emt
Digestion of the egg-
, White-columns in
m.m. atter
24 hours 2 > 24 hours
I Pancreatic juice: 3 drops + 2)), NaFl-solution: 5 c.c. 8 Is
9 ‘ ons} » -— extract in 2, NaFl sol.
Sec, 12 22
3 , : 3 , + boiled extract in 2'/9 NaFl
Solwouce: 9 19
i *. a » -+ distilled water: 5 c.c. 8 12
D > avis} » + 0.49/, CaCl, sol.: 24 c.c.
+ water: 2} c.c. 12% 9) 25
6 4 2/3} » +19 Cath, sol.: 24 c.c.
| + water: 23 Cc. | Ie 26
| |
7 | fs ol 1 GaGl solar 2k cic: |
-+- 20/9 NaFI sol.: 2} c.c. Gf 8
In the first place it appears from 1) that the pancreatic-juice con-
tained trypsin, for we observe that in a medium of a 2°/, sol.Nall
a not inconsiderable digestion had taken place. If the pancreatic-juice
had been entirely free from trypsin, in other words if it had con-
tained nothing but trypsinogen, then no digestion of albumen would
have taken place in a medium of a 2°/, NaFl-solution. From a
comparison between 1) and 2) it appears that in 2) the albumen-
digestion is greater than in 1). It foliowed from this that probably
not all trypsinogen had passed into trypsin, because it had to be
assuined that in 2) trypsinogen had still been activated by the ex-
tract from the intestinal mucous membrane.
Since this pancreatic-juice contained already free trypsin, we
evidently could draw no conclusions from it as to trypsinogen being
activated by chlorid of calcium; from this point of view, therefore,
this experiment had to be looked upon as having failed.
On comparing +) with 1) we see that after after 48 hours the
digestion in 4) is considerably less than in 1). This result must be
attributed to the fact that in 1) the bacteria-development was impe-
ded by the Nalkl-solution, whereas in 4) the bacteria were able to
develop themselves freely.
Bacteria (at least some bacteria, | shall, however, not enter into
this subject, as it does not bear on the matter under consideration)
ee ae i la te
6
( 1005 )
have directly opposite effects on trypsin and on trypsinogen, as |
gathered from a great many experiments. Whilst on the one hand
irypsinogen can be activated *) by the action of bacteria, on the
other hand the aetion of ¢rypsin is greatly impeded by bacteria (or
perhaps by the decomposition-products of albumen at the joint
action of trypsin and bacteria. The pancreatic-juice experimented
upon containing comparatively little trypsinogen and much trypsin,
the antitryptie action of the bacteria prevailed in this case upon its
activating influence, which also appears from the fact that in 4)
and 1) the albumen-digestion is still the same after 24 hours, whilst
after 48 hours (when all the trypsinogen in 4) could be expected
io have passed into trypsin) it is considerably less in 4) than in 1).
Obviously this experiment gives support to the opinion that the
influence of micro-organisms, in experiments relating to the activa-
tion of trypsinogen (and | may add by the way: likewise in expe-
riments on antitryptic factors) should by no means be disregarded.
The condition that the action of bacteria must be effectually
obviated in such experiments, e.g. when studying the effect of
ealcium-salts on the activation of trypsinogen, forms one of the diffi-
culties I alluded to just now. The more so, as it stands to reason
that in experiments with Ca-salts no NaFl may be used, which we
can also gather for instance from 7) Table I. As we see the diges-
tion in 7) is very inconsiderable. This must be attributed to the Fl.
of the NaF] having formed in this case insoluble CaFl, with the Ca
of CaCl,. The precipitate CaF], had sunk to the bottom of the test-
bottle, carrying part of the albumen of the pancreatic juice with it.
Hence the Mett-tubes had got enclosed in a thick precipitate of
CaFl, and panereatie albumen, in consequence of which tbe trypsin-
action on the Mett’s albumen-columns could of course not assert
itself so well.
Finally on comparing in Table | the numbers 5) and 6) with 1)
and 2), we might at first sight be inclined to assume that under
the influence of CaCl, trypsinogen had been activated, the digestion
in 5) and 6) being considerably greater than in 1), and as great, nay
even somewhat greater than in 2). On second thoughts [ arrived at
the conclusion that in this case not merely the actiwating effect of
CaCl, had to be considered, that at any rate there must also be
other reasons for the greater digestion in 5) and 6). Indeed it appears
from 2) that in this case the amount of trypsinogen could only be
1) For further ‘particulars on this subject see an article of mine in the Archiv.
fiir Anat. und Physiologie 1904 p. 343.
66
Proceedings Royal Acad. Amsterdam, Yol. XIIL.
( 1006 )
cmall, whilst as regards trypsin, the antitryptic effect of the bacteria
would have manifested itself in 5) and 6) as strongly as in 4), if
not another factor had been present, which promoted in 5) and 6)
the trypsin-action more than it was counteracted by the bacteria.
These considerations suggested the idea to me that chlorid of cal-
cium might perhaps have the property of stimulating the activity of
trypsin.
This would, moreover, explain the results of these, and such like
experiments, for I repeatedly found similar results.
As a type of the experiments, in which the pancreatic juice used,
was free from trypsin, containing nothing but trypsinogen, we may
quote the following (Table I).
TABLE i
| | | Digestion of two
albumen-columns in
Fluids added eae
Amount of Pancreatic- 5 Fi
| juice used | 24 hrs. | 2> 24 hrs.
1) | 2 drops + 2), NaFl-solution: 10 cc. | 0 | 0
+ intestinal mucous membrane | |
2) 2 ‘ extract in 2’), NaFl-solution: | |
10 c.c. 54 | 9
3) | 2 ‘ | +t boiled intestinal mucous mem-
brane extract in 2°), NaFl-
solution: 10 c.c. en) 0
4) 2 ” ; ; |
-+ 1°), chlorid of calcium-solu- |
tion: 5 c.c. + 2°/, NaFl-solu- | |
tion: 5 c.c. Fo 0
5) 2 ” i. .
+ 19) chlorid of calcium-solu- |
tion: 5 c.c. + water: 5 c.c. 2 6
6) 2 *) | + water: 10 c.c. 1.6 | 4
In the first place it appears from 1) and 3) of this experiment
‘Table ID) that in this case the pancreatic-juice used, contained only
irypsinogen and no trypsin. Regarded therefore as an investigation
concerning the activating effect of chlorid of calcium on trypsinogen,
the experiment could not be seriously found fault with. Except that in
this experiment no sterile water and sterile JaCl,-solution had been used,
which evidently should have been done in experiments on the activating
effect of CaCl, on trypsinogen. I intentionally quote an experiment in
which no sterile water and no sterile CaCl, were used, as being more
( 1007 )
to the purpose. An experiment like the one, detailed in Table I may
even more strongly than the preceding one (Table I) create an
impression, when we compare 5) and 6), that trypsin might be activated
by chlorid of calcium. In 6) the activation has undoubtedly been
effected by the bacteria, which have developed themselves in the
non-sterile water (+ pancreatic-juice); in 5) the greater activation
might have been caused by the joint action of bacteria and CaCl, .
And since in 5) the digestion was greater than in 6) there were
plausible reasons for concluding that chlorid of calcium had contributed
io the activation of trypsinogen. Still, as my attention had been
directed to the possibility of a stimulating action of chlorid of calcium
on trypsin, the difference in digestion between 5) and 6), when looked
at from this point of view, might find an explanation in this sense.
Further discussion of this experiment may be esteemed superfluous ;
I thought it advisable to insert it here as an additional proof that
we have to be very careful about conclusions as to a contingent
activating effect of chlorid of calcium on trypsinogen.
Whilst on the ground of the preceding observations it seemed not
unlikely that chlorid of calcium might have a stimulating effect on
irypsin itself, a closer investigation was begun now in order to test
this supposition by means of experiments. For this purpose I made
use of some commercial trypsin-preparations, viz. that of GrtBLER
and that of Merckx. As the activity of the preparations in the labo-
ratory was found to be very slight with regard to coagulated albumen
1 ordered fresh preparations a few times. I informed the firm of
Grisirr as to this slight activity, upon which this firm sent me,
as I was informed, a newly-made preparation.
Yet the activity of this preparation was no greater than that of
the preceding ones. That is to say as regards albumen, as regards
fibrin the action of these preparations left nothing to be desired.
By making the concentrations of the trypsin-solutions (suspensions)
considerably stronger than prescribed by the firm [ could use these
commercial preparations for my purpose. The trypsin-solutions
(suspensions) were prepared by means of soda-solutions. As the use
of Na,CO, seemed liable to some objections, however, owing to the
slight solubility of the CaCO,, resulting from CaCl, being added,
I made use of very weak (as a rule 0.1 °/,) solutions of Na,CO,.
That there was no objection to the use of a 0.1°/, sol. of Na,CO,
is seen from the following experiment, which for the rest served
to investigate the stimulating effect of CaCl, on trypsin-action (Table III).
For this experiment 1 gramme of trypsin-GrtBLer was dissolved
66*
( 1008 )
in 100 cc. Na,Co, of 0.1 °/,. The trypsin dissolved in it with a
slight opalescence, the solution was not filtrated before it was used.
To 5 ce. of this solution were added 5 ce. water and 5 ce. CaCl,-
solution, respectively.
TAB aE ul:
| Digestion of two
albumencolumns
in m.m. after:
224 hrs. | 324 hrs.
1) Trypsin sol. 1/100: 5 c.c. ++ water: 5 cc. 3 4
2) Trypsin sol. 1/100: 5 c.c. + CaCly sol. of 1%: 5 c.c. 9 15
3) Trypsin sol. 1/100: 5 c.c.-+ CaCl sol. of 1%: 2% cc. + 10 ib
water: 21/5 c.c.
From this experiment it appears that in 2) and 3) where CaCl,-
solutions had been added to the trypsin-solutions, the albumen
digestion was considerably greater than in 1), where water had
been added. We observe that the trypsin itself (1) showed very
little activity as regards coagulated albumen, though as I observed
before, 1 gramme of trypsin had been taken upon 100 ¢.c. Na,Co,
of O.1°/, (an addition of an equal volume of water making the
concentration 1/200). And further that this power was considerably
heightened under the influences of a 1 °/, anda 0.5 °/, CaCl,-solution,
respectively.
Still from this result it might not be concluded yet that CaCl,
had promoted the action of trypsin. And that, for this reason: the
trypsin-preparations might still contain some trypsinogen, which might
have been turned into trypsin by CaCl,.
Before continuing our experiments in this direction, we therefore
had to settle first whether the trypsin-preparation used, was indeed
free from trypsinogen. This question could be solved by adding in
a following experiment also intestinal mucous membrane extract to
the trypsin-solution and at the same time the boiled extract. {lt
is generally held, and in my opinion absolutely certain (Cf. 3)
Table Il) that boiling renders inactive the substance in the intestinal
mucous membrane extract which causes trypsinogen-activation ].
In order to solve the question whether the trypsin was free from
trypsinogen or not, it seemed advisable to make a double experiment
( 1009 )
by using in the first place a solution of trypsin in 0.1° , Na, CO,-
sol. (Table 1V A1—G) and secondly a solution of trypsin in a
2°/, Na Fl-solution (Table IV B 1—6).
As was observed already the trypsin-Grisier used for this expe-
riment (Table IV) was the same as that applied in the preceding
one (Table Ill); instead of a trypsin-concentration 1/100, 1/50 was
used. Moreover, as appears from this Table, an intestinal mucous
membrane extract in water as well as in 2°/, NaF l-sol. was taken.
It ought to be mentioned that the proper trypsinogen-activating effect
of the extracts of the intestinal mucous membrane was in all cases
tested by means of pancreatic-juice.
TeAGBe EaEy IV:
Digestion of the two
albumen columns
in m.m., after:
A es
Trypsin-GRiiBLER
1 gramme to 50 cc. Fluids added 24hrs 48hrs 72 hrs
Na,CO3 sol. of 0.1;
1) SCG: water: 2 c.c. 2 4 5
2) SCG; CaClg sol. (199): 2 cc. 8 16 20
3) SuGC; intest. mucous membrane-extract in
2 9 NaFl-sol. 2 c.c. 4 8 12
4) 8) (XS, intest. muc. membr.-extr in water: 2¢.c. 3.60) 7 10
5) 3: CC. Boiled int. mucous membrane-extract
in 29/, NaFl-sol.: 2 c.c. 4 8.50, 18
6) SCG. Boiled int. mucous membrane extract
in water: 2 c.c. 8 8 11
| Trypsin-GRUBLER
B \|1grammeto 50cc.
aa of a 2 9/, NaFl-sol.
1) 3. Ge; | Water: 2 cc. 3 6 8
2) ra} (Ser CaCly-sol. (199): 2 c.c. 0 0 0
3) BICC: intest. mucous membrane-extract in
2 %, NaFl-sol. 2 c.c. 4 8 12
4) SiGe: intest. muc. membr.-extr. in water: 2c.c. 4.40 8.50 12
5) SGC: Boiled int. mucous membrane-extract
in 29/9 NaFl sol.: 2 cc. | 4 9 13
6) SEC: Boiled int. mucous membrane-extract |
in water: 2 c.c. 4 850; 12
( 1010 )
From the preceding experiment (Table IV A and B) we may
conclude what follows. Comparison between A 38—6 and A, and
likewise between B 8—6 and B teaches that also in this experiment
the intestinal mucous membrane extracts have had a_ favourable
effeet on the trypsin-action. From the result that the albumen-
digestion in A8, 4, 5, and 6, and likewise in B 3, 4, 5, and
6 differed little or nothing, that consequently the oiled extracts
of the intestinal mucous membrane were found to have the same
favourable effect as the unboiled ones, we may conelude that in the
trypsin-preparation used, no trypsimogen was present. The fact that
6 was found to be
considerably greater than in A,, whilst this was also the case with
in spite of this the albumen-digestion in A 3
B8—6 and B, respectively, could in my opinion be explained only
by assuming that in the ertracts of the intestinal mucous membrane,
in ether avords, in the intestinal mucous membrane, a substance is
found which can promote the trypsin-action, a substance which
(contrary to the substance activating trypsinogen) could not be rendered
inactive by being boiled.
From the result that the trypsin used, was found to contain no
irypsinogen, it also follows that the favourable effect of chlorid of
calcium, observed in the preceding experiment (Table III) must be
attributed to the heightened action of trypsin, occasioned by chlorid
of calcium. The intensifying action of chlorid of calcium, as regards
trypsin, likewise manifests itself, and that very obviously, in the last
experiment (Table IV A and B). For in A, the albumen digestion
is seen to be much greater than in A,. That in B, no digestion
took place at all, must undoubtedly be attributed to a precipitate
of CaFl, being formed here, which had sunk to the bottom of the
test-bottle, and surrounded the Mett’s tubes, so that the try psin-action
could not manifest itself. Comparison between A 38—6 and A, shows,
moreover, that the stimulating effect of the intestinal mueous membrane
extract is a slighter one than that caused by chlorid of calcium, at
least in the concentration used‘).
Further it may be coneluded from A8 and 5 and B38 and 5
(Table IV) that the substance deriving its origin from the intestinal
mucous membrane, and promating the typsin-action, is in all proba-
bility no calcium-salt. For it may be assumed that a caleium-salt, if
it were present in the extracts used, would have been precipitated
by Nakl as insoluble Cakl,. This last observation likewise holds good,
!) An investigation as to the influence of the concentration of the chlorid of
calcium-solution, and also as to the effect of some other soluble caleium-salts on
trypsin, is in progess, but has not yet been completed.
( 1011 )
of course, for other salts which may be found in extracts of the intestinal
‘mucous membrane, in other words in the intestinal mucous membrane
itself, so far as they form insoluble compounds with Nak.
The results described in connection with the tables inserted, were
confirmed by other experiments made with the same view, which,
as was observed already, were carried out with different trypsin-
preparations of Grisurr and of Merckx. We subjoin one more experi-
ment, made with trypsin-Merck. (Table V).
AY By ES Ve
Digestion of the two
| albumen-columns
in m.m. after
Tryp-in-MERCK | |
| gramme to 50 c.c. lluids added 24 hrs'48 hrs 72 hrs
NagCO3-sol. of 0.1 |, |
SUC: Water: 2 c.c. 4 10 11
Sucre CaClo-sol. of 1%9: 2 c.c. | 8 20 empty
Succ: Int. muc. membr. extr. in 29) NaFI:2c.c. 4.40 16 | empty
SuCiCs Int. muc. membr, extr. in water: 2 c.c. 5.50} 15 |empty
3 Ge: Boiled int. muc. membr. extr. in 29%/o
NaF lis 2 ec: 5.60} 15 | empty
Saree Boiled int. muc. membr. extr. in water:
2c, 6 16 | empty
It is seen that the result of this experiment (Table V) is analogous
to that of the preceding one. Further remarks are not suggested
by Table V, except that comparison with Table 1V, shows that the
trypsin-Merck was somewhat more active than the trypsin-GroBLER,
a fact which could invariably be established in the experiments.
Se UMMA Ne:
1. The experiments described above have shown that chlorid of
calcium can increase to a considerable extent the activity of trypsin
which contains no trypsinogen.
2. This promotive effect of chlorid of calcium on trypsin should
not be confounded with the activating effect of chiorid of calcium
on trypsinogen, which latter property is aseribed to this salt by
several authors.
3. The extracts of the intestinal mucous membrane were also
found to possess the property of being able to increase the action
of trypsin, to a smaller extent, however, than chlorid of calcium,
« 1012 )
4. The substance originating in the intestinal mucous membrane,
which brings about this action, is not destroyed by being boiled, and
is in all probability no caleium.
5. Besides a substance which, as we know, possesses the faculty
of being able to activate trypsinogen, which substance 1s rendered
inactive by being boiled, the intestinal mucous membrane containe,
therefore, also another substance which has the power of stimulating
active trypsin, a substance which is not rendered inactive by being
boiled.
Groningen, January 22"¢ 1911. Physiological Laboratory.
Physics. — “J/sotherms of monatomic substances and of ther binary
mixtures. LX. The behaviour of argon with regard to the law
of corresponding states.” By Prof. H. Kamertincn Onnes and
©. A. Crommenix. Comm. N°. 1200 from the Physical Laboratory
at Leiden.
(Communicated in the meeting of February 25, 1911).
§ 1. The mean reduced surface of state for monatomic substances.
A diffieulty which is by no means small is introduced into theoretical
investigations dealing with the equation of state by the faet that,
for every substance, and, in particular, for substances of simple
molecular construction, the region that has been experimentally
investigated extends over a small range of reduced pressure and of
reduced temperature. If the law of corresponding states were strictly
obeyed, this difficulty could be obviated by reducing and then com-
hining with each other the regions investigated for the various
substances. In this way the mean reduced equation of state has been
synthesized: in the form VII. 1°). It has been obtained from Amagat’s
observations on hydrogen, oxygen, and nitrogen, Youna’s on isopentane
and Amacat’s and Ramsay and Youne’s on ether. In this way the
equation of state has been obtained for an imaginary substance which,
if further amplified by the disturbance function *) for the neighbourhood
of the critical point, is suitable for all calculations in which the
validity of the law of corresponding states is assumed. And _ this
equation is of particular use in tracing deviations from the law of
corresponding states, for it affords a suitable means or easily comparing
1) Suppl. N°. 19 (May 1908).
2) Proce. Febr. 1908. Gomm. N°. 104,
( 1013
individual results, which cannot be satisfactorily represented by a
special equation of state, with results obtained for other substances,
and, particularly, with results obtained for those substances which
have served for the calculation of equation VII. 1. When deviations
of some particular substance from the imaginary substance in the
same reduced state have been calculated, then, the far more concise
deviations from VII. 1. may replace the actual results of the experi-
ments themselves.Such deviations were determined for each of the
substances used in the synthesis of equation VIT. 1. with respect to
whose reduced surfaces of state that of VIi. 1. plays the part of a
quasi-enveloping surface. The critical temperatures of the substances
can greatly influence the differences existing between the separate
surfaces; the peculiarities of the molecules, however, can influence
them, too, in another way.
The object we had in view in our research upon the isotherms
of monatomic substances was to obtain, in the same manner as that
in which equation VII. 1. was obtained, a mean reduced equation
of state in the synthesis of which observations on monatomic substances
should exclusively be used. Unless in the structure of the various
atoms of the monatomic substances further peculiarities are discovered
which influence the equation of state, then, the only influence
exerted upon the form of the reduced surface is that of the critical
temperature. This influence will manifest itself in the deviations
of the special equations from the mean equation undisturbed by
other possible factors. And it is to be expected that the special
surfaces of state for the various monatomic substances should
systematically differ from the enveloping surface and from each
other in such a manner that a gradual transformation would change
the xenon‘) surface into those for krypton, argon, and neon, to
finally assume a limiting shape in the case of helium’). From the
sequel, in which is given a first, but very small, step in the desired
direction, it is evident that the mean reduced equation of state for
monatomic substances which we desire to optain, and which we
shall indicate by VUImon., will exhibit important characteristic differences
from the general mean equation VII. !.
1) We shall, for the present, leave out of consideration substances of higher
critical temperature.
*) It was remarked in 1881 that a separate equation of state would have to be
applied to each group of substances having similar molecules. (H. Kamer.incu ONnNEs.
Verh. Kon. Akad. 1881, Arch. neérl. 30, p. 101). The group of monatomic
substances has been made a subject of special study from this point of view by
H. Happet, see Ann. d. Phys. (4). 13. 340. 1904.
( 1014 )
§ 2. Comparison of argon isotherms") with those of isopentane
(Youne)*), ether (Ramsay and Youne)*) and carbon diowide (AMAGAT) *)
between the reduced temperatures 1.0000 and 1.1323.
In order to obtain a systematic comparison from the point of view
of the law of corresponding states between the results obtained for
argon and those for other substances, we have in the manner
indicated in § 1, calculated the differences between the observed
data for the various substances and the values obtained from VII. 1°),
To begin with, the critical temperature and pressure already published *)
were used in the calculation of the virial coefficients for argon
according to VII. 1, and. from these coellicients, deviations from
VII. 1 were obtained. It appeared to be most suitable to work with
percentage deviations of pr from values of pr given by equation VIT. 1‘).
The virial coefficients are given in table I and the differences in
table IT.
The deviations for isopentane, ether and carbon dioxide from
VII. 1. were calculated a considerable time ago; they form part of
an extensive research upon the differences between the empirical
equations of state for these substances as expressed by their deviations
from the general mean reduced equation, of which only a very
small part has yet been published. From amongst these, deviations
are taken which can be compared with the argon isotherms between
—100° C. and the critical point, that is, those which lie in the same
region of reduced temperature as the argon isotherms. The deviations
for all four substances were then united in one diagram in which the
deviations were plotted as functions of /og 4» in which 4=——
-
and »=—.
Uk
Hence, the critical volume does not appear in the expression
1) Proc. Dec. 1910, Gomm. No. 118 and GC. A. CROMMELIN. Thesis for the
doctorate, Leiden, 1910.
2) S. Youne, Proc. phys. soc. London, 1894/95, p. 602.
3) W. Ramsay and 8. Youne Phil. Trans, 178. 57. 1887.
4) i. H. AmaGat, Ann. de chim. e. d. phys. (6) 29, June and Aug. 1893.
5) For a critical examination of the observations it is also very desirable to
substitute deviations from VII. 1. for the actual observations so as Lo eliminate
experimental error, and to reduce to one common substance the results obtained by
different observers. Our results for argon were treated in this fashion before being
placed upon the diagram.
6) Proc. May 1910, Comm. N° 115.
7) For the method by which these calculations are made, ¢.f. Proc. June 1901,
comm. No. 71.
(1015 )
TeANB i ET.
| Virial coéfficients for argon according to VII. 1.
t | By . 10° Cy - 10° DD NOE TRE nea 1052 Fy - 10°
| Pa 2)Noi vt Es
+ 90.39C.) — 0.61763 + 9.91916 | + 4.39836 | + 7.6045 | — 4.35430
0.00C.| — 0.77633 ) + 2.91908 + 3.09635 | + 8.7321 | — 4 98937
= 57.726.) — 130816 | 45 2. 40uGR | — 0767139 | = 10.5255 | — 5 02409
87.0EC.| — 1.66571 | + 2.73556 | — 2.83014 | + 10.5566 | — 3.93044
— 102.51C.} — 1.89979 | 4+ 3.04873 | — 4.10121 | + 10.4013 | — 3 10842
— 109.88C.| — 2 02794 + 3.25078 — 4.76310 | + 10 3251 — 2.69045
— 413:80C.) — 240156 | ++ 3.37635, | — 5.43599 | + 10.2947 | — 2 47655
— 115.86C.) — 2.44198 + 3.44818 | — 5.35020 | + 10.2837 | — 2.35600
— 116.62C.) — 2.157238) + 3.47581 — 5.41531 | + 10.2806 | — 2.31432
— 119.20C.) — 2.21026 4+ 3.57411 | — 5.67996 | + 10.2759 | — 2.17669
— 120.24C.) — 2.93230 | + 3.61597 | — 5.78950 | + 10.2764 | — 2.12939
_— 121.21C, — 2.95318 | + 3.65616 | — 5.89340 | + 10.2783 | — 2 07246
— 130.38C.| —— 2. 46836 + 4.10021 | — 6.96874 | + 10.3966 | — 1.66293
— 139.62C.| — 2.72584 + 4.69951 | — 8.27734 | + 40.8045 | —- 1.42979
— 149.6CC. — 3.06753 | + 5.59972 — 10.45136 | 4+ 11.8440 | — 1.53961
5 Pk ae .
ay v; only the critical! temperature and pressure are used in
=k
the calculation of ’v, while, when different substances are being
compared with each other a single but undetermined value is ascribed
to 4 for all substances. This method which has already been adopted
on former occasions °
) has the great advantage that it is not necessary
to use the critical magnitude which is most uncertain, viz. the critical
volume, and only well defined magnitudes are employed. To make
2 the same for all substances, although it varies distinetly for the
various substances *) may well appear somewhat strange at first sight.
The systematic deviations of the various equations from VII. 1
revealed in the different values of 4 are not, Lowever, the only
systematic deviations to which expression will here be given. There
1) Proc, June 1901, Comm. N°. 71.
2) Proc. Febr. 1907, Suppl. N'. 14.
( 1016 )
Tea money i,
EA SS TS
Percentage deviations of pu, from pv, (C) of the general mean reduced equation VII. 1.
f é
O—C O—C 1 O—C O—C O—C | O—C
dy in dy in 94, aN in %% dy in 9% dy in Oly | ay in %/)
| | il |
a A ST EE LT aS
+ 209.39 C, | 09.00 C. — 579.72 C. — 87°.05 C. 1029.51 C. | — 109°.88 C.
90.499 | 0.0 | 20.877} 0.0 | 93.509 |40.4 | 25.4152 |+0.3 | 25.574 |40.5 | 26.242 |-+0.6
95.759 | 0.0 | 96.581 |\—0 4 | [28.575 |—0.2]| 34 467 |+-0.1 | 35.077 |+0.4 | 34.807 |4-0.8
32,590 0.0 | 32.302 |—0.41 | 33.793 0 2 | 55.822 |—0.4 | [47.893 70.9)) 65.142 |+0.8
35.759 | 0.0 | 37 782 |—0.2 | 48 116 |—0.3 | 71.444 |—0 2 |[53.752 |--0 9]| 87.176 |-+-0.8
47.319 | 0.0 | 51.840 |—0.5 | 64.948 |—0.4 | 94.625 |—0.7 | 62.240 |+0 4 102 76 |+05
59.950 |—0.1 | 65.325 |—0.7 | 90.695 |—0.9 |119 84 |—1.0 [69 954 | +0.9])125.56 +0.2
84.002 |-40 2 [148.32 |—0.2
95.802 0.0 180.84 |—1.0
145.88 |—O0.4
35.65 |-0.7
158.01 |—1.2
— 1139.80 C. | —115°.86C. | —116°.62C. | —119°.20C. — 1209.24 C. — 1219.21 C.
|
hitaeiad Tal
67.078|44 0 | 69.947/44.4 | 96 480/+0.9 | 26.871/44.0 | 72.627 |44.7 | 27 326)44.4
88.889-14.0 | 91.308/41.2 | 34.939/408 | 34.965/41 2 | 82 816 [42.0 | 35 983) +4.3
406.68 |10.7 | 108.02 |40.9 | 68 630)41.2 | 70 314/44 4 | 99.946 |490| 71.459/41.8
131.51 |40.6 | 90 563/412 | 70 481/41.0 /448.51 |44.8 | 85.580/42.0
455.42 |40.4 | 110.49 |+09 | 83.257|44.4 |136.31 |44 7 | 100 33 |44.8
oo =
129.17 |-0.
152.71
155.40 | 00 | 179 94 |\—0.5 | 133.69 |+0 7) 96.83444 5 /165 79 |+0 9 |[123.85 |441.9]
182.13 |—0.5 |[183.35 |4+4.8]) 159.71 |+0.2 | 98.863)44.0 206 57 |+014 | 148.95 |41.6
184.82 |—0.7 | 235.47 |—1.7 | 161.75 | 0.0 | 124.97 |+.0 6 |280.25 |—0.7 | 170.05 |-+-0.9
2.99 |—1.4 | 319.52 |—2.9 |[186 45 |—0.4]|[143.71 |+-0 9]/338.95 |—0.5 | 234.43 |—0.2
210 02 |—0 9 | 156 36 |—0.4 333.75 |—0.4
[260.61 |—2.0]| [172.25 |4-0.6]
331.29 |—2.8 | 222.69 |—1.8
275.02 |—2.8
— 130°.38 C. | — 1399.62 C. — 149°.60 C.
97.394/ 44.7 | 98.499
31.583)/-4+4 .2 5
34.726|-49..0
55.807|-42.9
65.125|43.2
77.8244 2
101.71 |-43.3 |
99.4183 |3.8 |
34 646 [14.4
( 1017 )
is, therefore, no danger in uniting this one kind of deviation with
the other ones in the common representation which we try to obtain
for them. According to the method we followed it appears to be
possible to unite all deviations from the law of corresponding states
in a single representation as definite as can be desired for the present;
but, of course, we do not mean to say that it might not be found
more suitable in a more extended and more searching study of the
deviations from the law of corresponding states to adopt a different
method of summarising these deviations.
In order to be able to ascribe the same value to 2 in every case,
all the volumes must be expressed in the same unit. This was not
the case with the observations which are now being dealt with, so
that some reductions were found necessary. va , volumes in the argon
isotherms and in the carbon dioxide isotherms are expressed in terms
of the experimental normal volume, while those in the isopentane
and ether isotherms are expressed in terms of the number of cubic
centimetres per gram of the substance. Since we wished to express
2» in terms of the theoretical normal volume for all the substances
we calculated its values according to the following expressions :
arte Pk
for argon and carbon dioxide: 2» = — YN ®
df Alar
sone , PY
for isopentane and ether: Av = — De 2)
TA
Le SR pee ;
In these expressions sty, = is the ratio of the experimental to
UN
the theoretical normal volume, and y is the specific mass *) in grams
per ¢.c. at normal temperature and pressure.
Values of log 4x, were marked off as abscissae, and as ordinates
values of the common logarithms of the reduced temperatures. Lines
parallel to the Jog av axis represent the course of the equation VIL. 1,
while deviations are marked off from these lines, (positive above,
negative below) in such a way that a 1°/, deviation corresponds to
5 mm. on the accompanying diagram. We shall call this method of
exhibiting the deviations in a diagram “arranging according to /og t
the deviations expressed as functions of Jog av.” From this drawing
which, since it contains the deviations for the various substances at
the different reduced temperatures (the observation temperatures of
the isotherms), has been somewhat abridged, the deviations for each
1) Arch. neérl. (2) 6, 874. 1901, Comm. No. 74.
2) In all these considerations we may neglect the difference between the specific
mass and the density (aumber of grams pro m. L,).
( 1018 )
substance for suecessive values of /oy Jy were now read off, and
the values thus obtained were then graphed as functions of Jog ¢,
arranged according to /oy 4. By reading from the graphs thus
deduced, the deviations for the various substances were brought to
the same reduced temperature. For these reduced temperatures were
chosen the temperatures of the argon isotherms, viz.
1.00816, for argon corresponding to —121°.21 C.
1.01460, _,, . $3 120°.24
fF 0.3 . »» ~—119°.20
1.03863, ee Eo (op)
1.04368, _,, 55 . 115°.86
105735; ,, 55 PF 5» —113°.80
1.08337, ,, 5 sf » —109°.88
1A3229) 5, 5 965 55 —102°.51
And finally, the deviations were graphed as funetions of log dx,
and all reduced to the same temperatures. This diagram is repro-
duced on the Plate accompanying this Communication. The deviation
curves for the reduced temperatures 1.01460 and 1.04368 could not
be drawn on it, as in order to do this distinctly the scale would
have to be made too great. The rectangle on the right hand lower
portion of the diagram borders the immediate neighbourhood of the
critical state. It is best, while employing this method of critically
examining the deviations, to leave this region out of account pro-
visionally, as otherwise one would have to allow for the influence
of the disturbance function '). A description of the information afforded
by this plate concerning the deviations of the various substances
seems tO us unnecessary; it speaks for itself, and gives clear ex-
pression to the systematic deviations of argon from the other sub-
stances in this region.
§ 3. Caleulation of certain data which ave of importance in. the
discussion of deviations from the law of corresponding states.
To get an idea of deviations from the law of corresponding states,
certain data are usually calculated, and we are now able to obtain
their values for argon from our former experiments. *)
3) Proc. Febr. 1908. Comm. No, 104.
2) Proc. May 1910, Comm. No. 115; Proc. Dec. 1910, Comm. No. 118a; Proce.
Dec. 1910, Comm, No. 1180.
( 1019 )
a. By substituting values of argon vapour pressures in the well
known Van per WaAAts vapour pressure equation *)
P i Dye
loa ——wi ==
” Pk s ali
and using common logarithms we get the following values for /:
|
t | p in atm. | if
| |
| |
—140°.80C.| 92.485 | 2.415
—134°.72C.) 297964 | 2.421
—129°.83C,) 35.846 | 2.457
—125°.49C.| 42.457 | = 9.577
|
A cursory comparison of these values of f with those for other
substances shows us that the value for argon is closer to the theoretical
value of f at the critical point deduced from van DER WaAALs’s
equation (1.737) than the values belonging to by far the greater
number of other substances; this is what one would expect for
monatomic substances. For carbon dioxide between —638° C. and the
critical point f goes from 2.84 to 2.977*); for isopentane *) between
130°C. and the eritical point 7 assumes a value between 2.75 and
2.95, while it further appears from the list published by Kurnern ‘*)
that, with the exception of monatomic substances and a few others
such as hydrogen, oxygen, and carbon monoxide, values of / are
always still greater.
6. From the critical data already published, and from the weight
in grams of one litre of argon at normal temperature and pressure
which, according to Ramsay and Travers *) is 1.782, we found for
the critical virial quotient
raf A ~
K, = ——— = 3.283.
Prk
This value is also closer to the theoretical value deduced from
VAN DER WaAats’s equation, 2.67, than those of almost all other
1) J. D. van per Waats, Cont. I, p. 158.
2) J. P. Kunnen, Die Zustandsgleichung, p. 101, supplemented by KEEsom’s
measurements, Proc.Jan. 1904, Comm. N?. 88.
3) S. Youne |. ec.
4) J. P. KuEnen, |. c. p. 142.
5) W. Ramsay and M. W. Travers, Proc. R. S. 67. 329. 1900.
( 1020 )
substances, as is evident from the table of values given by KugNEN *)
Hence, D. Berrurtors ?) estimate is probably mueh too low.
c. Let us write the equation of the rectilinear diameter of CarLLurer
and Maruias*) in the form
Vliq = UYvap
2
ri
— a (7 — T)
in which giq, ¢vap and eK are ihe liquid, vapour and critical densities
respectively and « is the slope of the diameter; calling
1)
ay = — a
Qk
Q
K
the reduced slope, we can, with the liquid densities published by
Baty and Doynan‘), and the value of the critical density already
published, deduce from the isotherms
« = — 0.008050
ay = 0.9027.
The inclination of the diameter for argon is, therefore, unusually
great — greater than has ever yet been found for any other substance,
since « for most substances lies between — 0.0005 and —0,0023 °*).
In connection with the foregoing, it is of interest to note that
Youna °) discovered an intimate relationship for substances of higher
critical temperature between the diameter’s inclination and curvature
and the values of the eritical volume deduced from the law of the
diameter. Representing the curved diameter by
D = aa + bat + cat?
pki ( Ie cal )
me Vig Yvap ;
then we obtain the following corresponding relations
= ba <20:93," Kea 3-77 ta 0
SSSR ica seni ty =)
te 098 Kj si? Saou:
On a former oceasion’) the diameter was considered to be straight
in whieh
oy)
') J. P. Kuenren, Die Zustandsgleichung, p. 60.
2) D. BerrHetot, Journ. de phys. (3). 10. 611. 1901.
. GaILLETET and E. Marutas, Journ. d. phys. (2). 5. 549. 1886.
C. C. Baty and F. G. Donwan, Journ. chem. Soc. $1. 911. 1902.
Maratas, Le point critique des corps purs, p. 9 and 10.
. Youne, Phil. Mag. (5). 50. 291. 1900
-roc. Dec. 1910. Comm. N°. 118a.
oN oe
=
—
rg
(1021 )
for argon, and the assumption was then justified; we must, therefore
put cy =O. But we have just found a value for A,, and, since
K,= Kya‘) it follows that
Kage 3-283, and, —— hq = ay = 0.9027:
From this we may conclude either that argon is an exception to
Youne’s rule, or, as is not impossible, that its diameter is somewhat
curved, in which case it would belong to the first group given by
Young. An accurate experimental research upon the diameter for
argon would probably lead to important results bearing not only
upon this point, but also upon the question of the value of the
critical density of argon.
For oxygen Marnias and KamernincH OnNes *) found
Sas rae: it
— ba == (I tealai K 4a —=Fose
It appears, therefore, as if values of Avyqa in Youne’s criterion
become smaller and smaller the lower the critical temperature of
the substance.
d. We can, in the meantime, say nothing definite about the function
investigated by Retncanum *) and by Vocer‘). An investigation of
this point is, however, in progress.
!) The subscript d in A4q is used to indicate the fact that the value of the
critical volume with which this number is calculated has been obtained from the
diameter. Allhough the value here given for the critical virial quotient has been
obtained from) a value of vy calculated from the isotherms, we have, nevertheless,
assumed that we may write K4—= Kua, seeing that probably the two values of
vm: obtained by the two different methods differ but little from each other. (See
Comm. No, 1184).
*) Proc. Febr. 1911. Comm. No. 117.
3) M. Rerncanum, Diss. Gottingen 1899. Ann. d. Phys. (4). 18. 1008. 1905.
Phys. Ztschr. J1. 735. 1910.
') G. Voarn, Diss. Freiburg (Baden) 1910, Ztschr. f. phys. Chem, 73. 429, 1910.
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1022 )
Botany. On the connection betivecn stimulus and effect in photo-
tropic curvatures of scedlings of Avena sativa, By W. TH. Ariss.
(Communicated by Prof. F. A. F.C. Wen).
At about the same time there appeared in 1908 papers by
Buaauw') and by Fréscurn*) on the perception of lightstiniuli.
If a seedling of Avena or Lepidium is unilaterally illuminated,
then with different intensities of light a just perceptible reaction was
found to take place, when the product of the intensity of light and
ihe duration of the stimulus was a constant.
A repetition of these investigations in Professor Went’s laboratory
led to some observations of which | here give a preliminary account,
Madame Potowzow *) showed for aerotropic and geotropic curva-
tures, that under the imicroscope a curvature is seen to occur
immediately after the stimulation. BLaavw ‘) discusses to what
extent this may also be regarded as probable in the case of photo-
tropic curvatures. He is of opinion, that either the reaction where
40°
30°
20°
30 Min 60M 90 Min.
3
Fig. 1.
Course of the pholotropic curvature afler Braauw.
On the abscissa the time in minutes from the beginning
of stimulation, on the ordinate the magnitude of the angle of deviation.
it has become macroscopically visible must just have beeun or
that at this moment a new stage in the curvature process has
been entered upon, and that therefore in any case he is working,
with a definite point of the reaction.
1) A. H. Braauw. Proc. Acad. Sci. Amsterdam, Sept. 1908.
*) P. FréscHet. Sitzungsberichte der K. Akad. der Wiss. Wien, April 1908,
5) W. Potowzow. Untersuchungen iiber Reizerscheinungen bei den Pflanzen. 1909.
) A. H. Buaauw, Die Perzeption des Lichtes. Recueil d. Tray, Bot. Néerl. Vol. 5,
1909.
1023. )
It remains to trace also the course of a phototropic curvature —
with the microscope in the same way as PoLowzow did for geotropic
curvatures.
In view of the manner of curving, to be described later, the distance
between the original position of the tip of the coleoptile and the
new position occupied at any moment during the curvature is chosen
as the measure of the curvature at that moment. Mau.rrer') and
Potowzow also took this distance as a measure of the curvature.
In the eye-piece there was a net-micrometer, so that if was possible
to make under the low power a drawing on squared paper of the
whole apex.
by comparing these drawings, made every 5 or 10 minutes, it
was possible to trace the origin of a slight alteration in shape.
Nutations gave a good deal of trouble, though all specimens in
which these occurred were absolutely rejected. Since the nutation
movements are sharply distinguished from a phototropic curvature
by the change of position of the whole apex with respect to the
base, it was fairly easy to recognise them.
In the following curves the abscissa is the time and the ordinate
the strength of curvature, measured in the afore-mentioned way.
In one case therefore the curvature began after 12 minutes. Are
we then to conclude that the curvature begins just at this moment
and that the reaction time is therefore 12 minutes? I think not;
it seems to me it would appear that we must come to this conclu-
sion after a study of the shape of the apex at the beginning of the
curvature. It is found that while this shape is at first almost exactly
conical with a somewhat blunted top, the curvature becomes visible
as a slight mutual asymmetry of that side of the cone which is
turned towards the light and that which is turned away from it.
This asymmetry becomes gradually more marked until the apex be-
gins to bend forward and the curvature extends further and further
from the apex. There is no indication of the sudden appearance of
curvature. In a few cases the shape of the apex favours the perception
of even a slight asymmetry, but it is very probable that in such cases
a curvature occurred, even before a deviation was traceable.
The determination of a reaction-time is therefore experimentally
impossible, and it is quite conceivable, that the curvature ocewrs
immediately on stimulation.
The passage of a part of the curve which is only visible micro-
1) A. Maitirrer. Etude sur la Reaction géotropique. Bull. Soc. Vaudoise. 1910,
67*
( 1024 )
Imm
8mm
Tm.
6mm
Smm
4mm
3mm
20m 40m 60m. 80m 100m. 120m 140m 160m. 180m 200m 220m. 240m. Time
Fig. 2.
Course of the phototropic curvature.
A. stimulated with 800 M.C.S. B. witli: 112 M.C.S.
C. wilh +20 MGS. D. with 5 M.CS.
scopically into a part which can also be perceived macroscopically,
takes place more or less gradually.
An obvious break oecurs on strong stimulation {see fig. 2 A).
Braavw’s interpretation, that the curvature here enters on a new
phase, seems to me very plausible, when we see that just at this
moment the paris remote from the apex, which in contradistinetion
tothe apex itself show a considerable increase in length, begin to
take part in the curvature.
On comparison of curves obtained in such a way, it beeame ob-
vious that the maximum curvature seen in plants which were ilu-
( 1025 )
minated with different intensities, was not equally great in every
case; with weaker light it was considerably less.
It was found that slighter curvatures exist than those observed by
Braauw and by Froscugt. This was a quite unexpected result, for
authough Braauw had very cautiously spoken of those curvatures
which were only just macroscopically visible, he still believed he
was working with a threshold of stimulation.
This applies still more to Froscunn, who attached great value to
the smallest product still giving a curvature, as a measure of photo-
tropic sensitiveness, for comparison with that of other plants.
Has the deviation of the apex valued by Braauw as. still
showing curvature, any special value, to which alone the rule of
products applies, or would it be found, that to a smaller or greater
energy of stimulus there also corresponds a smaller or greater
curvature? In general, that a definite quantity of energy causes a
definite extent of curvature t
In order to obtain an answer to this question a larger number
of experimental data had to be available.
The tedious observation with the microscope was superseded by a
much simpler apparatus. A photographic lens, magnifying 2 times,
projected the image of the seedlings on a glass plate, upon which a
scale of half-millimetre squares had been photographed. The position
of the apices was read by means of a simple lens.
The advantage of this arrangement is that in addition to a greater
number of plants, the whole coleoptile can always be observed.
The deviation of the apex from its original position before the be-
ginning of the curvature, chosen at the moment when this distance
is greatest, was taken as the measure of the magnitude of the cur-
vature. Since from the beginning gravity opposes the curvature,
there comes a moment when the apex under the. influence of photo-
tropism moves no further from the vertical, because phototropism
is neutralised by gravity. Although this point will probably give no
accurate idea of the sensitiveness, it is here only necessary to have
a fixed point of the curvature-proces.
Out of many observations made, I here bring together the fol-
lowing, which hold good for seedlings of an average length of 22.5 m.m.
at a temperature of about 17.5 degrees Cent.
The light energy was obtained by various comoinations of inten-
sities by stimulation periods of various lengths. (from 2 to 240 sec.)
The intensities were determined by a Weser ') Photometer.
1) Prof. H. SNELLEN, Director of the Dutch Eye Hosyital was kind enough to
place this photometer at my disposal.
( 1026 )
Light energy Magnitude of the maximal Number of observations
in M.C.S. *) curvature in mi.
7.6 0.73 12
12.4 0.96 6
18.1 1.47 10
26.1 Dall 6
44.2 2.8 Ua)
54.0 3.0 7
65.0 3.4 16
Nore 3.9 7
99.0 4.6 13
126.6 4.6 11
144.0 4.3 10
239.0 4.9 10
576.0 3.6 ila}
These figures are found to be on a smooth curve, which therefore
represents the relation of energy and maximal curvature.
Fig. 3.
Magnitude of the maximal curvature.
iomkS 20 30 40 50 60 70 80 90 100 110 120MkS
Energy in MGS.
The curve gives the relation of light energy used as a stimulus
and the magnitude of the maximal curvature for plants of
+ 22.5 mm. length and a temp. of 17.5° Cent.
') M.G.5. Means the product of the intensity of the light (in Meter candles)
and of the lengtn of the exposure.
( 1027 )
Up to 100 M.C.S. there was an increase in the magnitude of
the curvature, at first more rapid and then somewhat lower; from
100 M.C.S. to 400 M.C.S. the same maenitude, after which
there is a decrease. Below 7 M.C.S. the curvature could not be
measured by this method, up to 2 M.C.S. the curvature, as a faint
inclination of the apex, was still clearly visible macroscopically,
These apical inclinations have been noticed before, e.g. by Rurarrs *),
who did not however recognise them as phototropic curvatures,
because they also arose without previous stimulation. Control-experi-
ment which | made, showed however that when coleoptiles, which
showed absolutely no inclination of the apex, were placed in the
dark and care was taken that they were previously stimulated
neither geotropically nor mechanically by touch orgsimilar agency,
they showed no apical inclination, whereby, however (Rurcers I. c.
p. 56) attention was only paid to the curvature at right angles
to the plane of nutation.
Below 2 M.C.S. the curvature was so faint, that macroscopically
it could not be recognised with certainty. The microscope is likewise
inadequate for this. The smallest curvature observed was about */, mm.
at 1.4 M.C.5.
No limit can therefore be fixed below which no curvatures arise,
but that there are curvatures which at present escape our obser-
vation, is highly probable. The suggestion is obvious, and the course
of the curve is an argument in favour, that the curve should be
continued to point O. The significance of this is, that every quantity
.of energy gives rise to a definite degree of curvature.
Each quantity of energy reacts on the plant and is expressed by
a curvature of depiniteTmaaximal strength.
Since the phototropic curvatures with which these observations are
concerned, were all to some extent counteracted by gravity, it was
desirable to bave for comparison experiments, from which the uni-
lateral action of gravity had been eliminated. For this purpose Fit-
ting’s intermittent clinostat was used, which makes it possible to
place a plant during equal intervals alternately in positions which
differ from one another by 150 degrees, so that the action of gravity
in one position balances that in the other. In 2 minute periods no
appreciable curvature arose in unilluminated plants after 6 hours.
Out of every 4+ minutes the plants were for 2 minutes in a position
in which they could be examined and drawn under the microscope.
1) A. A. L. Rureers, De inyloed der temperatuur op den praesentatielijd bi
geotropie. Dissertatie, Utrecht 1910.
( 1028 )
The curve below gives the course of a curvature of this kind,
Deviation of the apex in mm.
In
40min 60 120 160 200 240 280 320 360 400 min.
Fig. 4.
Course of the phototropie curvature whilst the unilateral action
of gravity is eliminated. Stimulated with 560 M. C, 5.
It is clear from this curve that already after 10 minutes, sooner
therefore than when gravity is Opposing, a curvature becomes visible ;
this is of course a strong argument in favour of an earlier beginning
of the curvature-process. After about 6 hours there comes a moment
in which the distance from the vertical no longer increases. In order
to facilitate a survey of the curvature | here reproduce figures made
from drawings on frosted glass by outlining the image projected by
the photographie lens.
If one compares with this a curvature in which gravity opposes,
the great difference is at once striking. In this case too, first the
becoming asymmetric of the apex, after which the curvature affects
more and more basal zones. After about 6 hows the greatest deviation
of the apex is reached. If the strength of the curvature is determined
at this moment by placing ares of different radius along the curved
part, it is found that the coleoptile is not bent in the are ofa circle
but consists of a series of parts with different degrees of curvature.
Thus the zone situated fairly close to the apex is most strongly
curved, perhaps because it is the zone of most active growth. After
these 6 hours the curvature of the uppermost part decreases, so that
a slight diminution of the deviation of the apex is observable; it is
the beginning of the straightening out. In the more basal parts the
curvature still increases continuously. Finally the whole upper part
( 1029 )
‘avity is not eliminated.
(25<):
gravity is eliminated.
se of the curvature whilst the unilateral action of g1
Ae
hour
27
+95 M.C
oe a
a
a
» 4 hour
hour
ame quantity of light
PY
in. 3hour 5
3 hour
f 6 hour 14 hour 2
5 hom
Fig. 5
» of the curvature whilst the unilateral action of 2
14 hour
90 min
i hour
A
DS
A and B stimulated by the s
<=
becomes straight and the Gurvature in the base has become fixed.
Perhaps we possess therefore in this method of observation with
an intermittent clinostat a more accurate means of determining the
sensitiveness of the plant.
If we once more trace how far the above investigations influence
our conception of the process of stimulation, it is clear that the
comparability with physico-chemical processes becomes more and more
marked. The existence of a threshold of stimulation can no longer
be maintained, for not only is each quantity of energy perceived but
it is clear now that a reaction will always take place. The time
which intervenes between the application of the stimulus and the
( 1030 )
beginning of the curvature, “the reaction-time’® was found to be
experimentally undeterminable. Thus the latter can not serve as a
measure of sensitiveness.
It is more and more evident that such concepts as “Erregung”
and “Erregungshdéhe” can be perfectly well dispensed with, because
the phenomena do not give the slightest indication of their use.
Similarly the determination of an index or time of relaxation will
be found impossible, because it is impossible to show experimentally
that no curvature results from the summation of intermittent stimuli.
Since the presentation-time has been conceived as a factor of the
quantity of energy, which is just able to traverse the threshold of
stimulation, it follows from the above investigations, that when the
“Schwelle’ is abandoned tie presentation-time loses mneh of its
value as a special stimulation period. It remains however, as a time
factor of the quantity of energy, which results in a curvature of
definite strength.
Henceforth therefore the physiology of stimulation must be inves-
tigated by considering the energy which is applied as stimulus and
whieh is determine! by the product of the intensity of the operating
force and the length of the stimulation period, whilst the reaction
can be ganged by the degree of the maximal curvature, at least if
the unilateral action of gravity is not eliminated. If the latter be
in minutes.
Curvature-time
10 20 30 40 50 60 70 80 90
Energy in M. C. 8.
Fig. 6.
Relation between Energy and the time untill the curvature
becomes just macroscopically visible.
(1031)
eliminated the degree of curvature at the moment when straightening
out begins, can perhaps serve as measure.
If one wishes to investigate the influence of some external condition
on the sensitiveness, one can determine what quantity of energy
gives a definite degree of curvature each time this condition is varied ;
in which case it is very convenient that the moment at which
such a curvature becomes visible, is constant.
What was formerly understood by reaction-time but what has
now been found to be almost exclusively curvature-time, is constant
for a definite quantity of energy. This curvature-time greatly
increases according as the energy of stimulation is smaller, a fact
clearly shown by the following curve.
In conclusion TI wish heartily to thank Dr. Brasvw and in parti-
cular Professor Wenv for their kind interest and advice.
Utrecht. dot. Laboratory.
Crystallography. — “On the orientation of crystal-sections.” By
J. Scumutzer. (Communicated by Prof. C. E. A. Wicumann).
(Communicated in the meeting of ebruary 25, 1911).
When determining the orientation of a secant-plane from the
angles that the traces of three unparallel planes not lying in one
zone include together, one generally obtains a biquadratic equation
in cos 20, furnishing as maximum 4 compatible roots. As now angle
20 can be supposed at the same time in two quadrants, it follows
that one finds 8 values for 9. With these values correspond 8 values
of o. If however three crystal-planes and a definite crystal-section
are given, the secant-plane is entirely determined; which value of
eo and of © comes in consideration here, can be decided witli certainty,
if one takes into account the circumstance that a erystal-plane is at
the same time the boundary-plane of the mineral substance.
Being admitted a plane (A//) (ef. fig. 1) the pole of which lies in
p, and forming with the plane C (1 c-axis) a secant-line 44, then
a : ; :
the angle DBE=a< ; is filled with mineral-substanee, the obtuse
angle HG/ on the contrary is not. Now one can suppose the projection-
globe divided into 8 octants of which 4 are lying above and 4 beneath
the projection-plane C, and of which the first two (BOD=1,
DOA = I)) contain the acute plane-angle DBE. If one fastens s to
the coordinates « = ~ BM, o= Ms, then s lies in the 1s* elobe-
octant, caleulated from AB; for a plane 7” A£/) s lies in octant UI.
( 1032 )
The plane S cuts P? (Ak/) according to the line /O; the mineral
substance lies to the right of this secant-line, as is indicated by the
hatching. If with a constant value of 6(6=6,), @ increases, then
the angle h= 4 GOF, which for s (9,6) in the first octant > 0
Tv Sorta 5 2 T c
and < —, diminishes, till with 9 = — the value 4=O is reached
9 , 5)
« -
. . T .
Now becomes 4 <0, obtains in the HP octant a value — — ; with
lhe. oie Mt
@=—x is h—=—axz; in thesiV™ ociant ther value Jee 5 x is
surpassed; and at last with @ = 2a / obtains the value —2a+h,,
in which /, is the angle, that corresponds to @ = 0, 6 = 6,.
Fig. 2 represents the change of angle h for a plane V (« = 60°),
( 1033
in whieh v increases with 30° and 7 = 60°. For g, =0 h= 73°54’;
with increasing gy, / diminishes, becomes =O with g, =
cs »)
Lori) 10 bud , = T M TOC Or 2/
= — 73°51’ with vy, =z,=—->F with gv, =199°28’ and reaches
the value of — 2a ++ 73°54’ with 9, = 22.
It is further indieated in the figure, that with equal absolute
values of 9 and 6 fh is identical in the octants | and VIII, Il and
VII, Ill and VI, IV and V. In tthe central circle it is likewise
indicated, that the cotangent in the quadrants | and 8 > 0, in 2
and 4 <0. Now, as may be deducted from the diagrams fig. 4, 5
. . T . . . .
in the former communication, with «<< 5 h varies for different values
of o and o, in the oectants I and VIII exclusively between O and
1 x
=, in If and VII between 0 and — >. In ig. 2 consequently the
octants I and VII resp. I and VII never extend over the quadrants
1 and 3: the octants TV and V however do so over quadrant Land
III and VI over 4+. Consequently if one finds from the ratio
ae cos 6 cot a@ +- sin 6 sin Y
COS Yv
coth >0O, then 4 must be admitted in the first quadrant, if s(g, o)
lies in one of the octants I, IV, V or VIII, and in the 3°¢ quadrant
if s lies in III or VI. If coth <0, then / lies in the 2°¢ quadrant
with s in IV or V, and in the 4 if s lies in the IJ! or VII“
octani.
x X
As regards the planes with «= > and « > |, the figure speaks
- _
for itself. Consequently the results obtained here may be summarised
in the following table :
coth>0 coth<0
|
I IP) Wi) IV} V |} Vij) Vil | VII) 1 It | Wl) IV) V | VI) VIL} Vil
Seer ete) ) tL S | | L | die rAd | MOO Oy Mirae as, Nhe
a
a“ 5 os — | — ee ee i ree PAT PRIN a yl
uw .
a> hess) 3 |S ee | Cal Oe alt ch
( 1034 )
Of a trigonal prism are given the planes 1”, (OT10) and 17, (1010),
further 17, (OOO). Th one admits the latter plane as projection-plane,
x
then becomes a, = a, =—; y= 120°.
»
=
G
Ty;
Yff
If further one measures between the traces of V,:7, and V7, :V,
successively the angles 4, = 76°, 4, = — 53°, then furnishes (1)
cot 76° == sin 6 tg o
and
cot 53° = — sin o tg (vy — 120°)
from which:
cot 76° -- cot 53° cot 76°
ig 60° cot 53° © 53°
hy cot 53 cot 53
ty 9 = 1,07592 of —0,30754.
tq” C=
From this the values are found:
o,=47°5'58"; yy, =—132°54'2"; gy 4+ 162°54'17"; y= — 17°5'43"
7, =13°33'49"; o,—= 18°33'49", ¢,—= —54°9'58"; g, = 5490/53",
Be in fig. 8 AB the trace of I’, (OOO1), then
CD(Z DOB =h, = 76° and EF (7 BOE=h, =—53°)
indicate the direction of the traces of V7, and V’,. The plane S, (¢, 7,’
has its pole with regard to J’, in octant I, coth, > 0, h, consequently
lies in quadrant 1; with regard to J’,, s, lies in oetant IV, coth, <0,
h, in quadrant 2, whilst 4,—=0, and the trace of J”, consequently
shuts off the section at the top. Consequently the section @ corre-
sponds to the secant-plane S,; in the same way one finds, that the
( 1035 )
sections 4, c, and d have relation to the secant-planes S,,S,, and S,.
And in this way a choice between the four poles found has become
possible with certainty.
If the orientation of the crystal discussed here, must be determined
with the help of 2 erystal-planes and one cleavage-plane, then two
solutions remain satisfactory, as is easily seen, whilst with 1 crystal-
plane and two cleavage-planes, or likewise with 3 cleavage planes all
4 solutions may be taken mito consideration.
Cristallography. — “On the determination of the optic acial-angle
from the extinction-angle avith regard te the trace of a dis-
cretional plane ina diseretional crystal-section”. By J. SCAMUTZER
Communicated by Prof. C. E. A. Wichmann).
(Communicated in the meeting of February 28, 1911).
Be in fig. 1 the projection-plane perpendicular to the bisectrix of
the optic-axes, A and /& and be further S(s) the secant-plane, then
the directions of the vibration in the slide are given by the planes
that halve the angle aAs/ and its supplement.
Be angle « the inclination of the bisectrix (() on the secant-
plane S; ~/AKMH—=+ the angle, enclosed by the secant-lines of
the planes AOL and S with the projection-plane, then, as was
Kig. 1.
deducted before, in the plane S the extinction with regard to the
secant-line Of7 can be found from the equation :
( 1036.)
vol 2y cot 2 ~ FH = cot (~ DFH + —~ GH) =
] — sin? Vsin? a ] 1 — sin’? Veo a .
— - ——. -. | - ————-sin@. . (1)
sin 2a. sin? J sin wv sin 2a sin? J
If the pole s of S is fastened to the coordinates y= ~/KL,
s
o = ~ [s, then (1) changes into
: | — sin? V cos? y | 1 — sin? Vsin?o ,
cot 2y = = ———— — — - ar i
: sin 2u sin? | sin O sin 2u sin*
u u
1 — sin? V cos? vy — (1 — sin? V sin? v) sin® 6 )
sin 2y sino sin® J
¢
To every value of cot 2y correspond two values of y, which differ
90° from each other, and which indicate the direction of the vibration
of the quick ray resp. of the slow one. Without more the direction
of each of the ellips-axes cannot be deduced from the formula; to
find it afterall, one acts in the following way.
octants cab, bac’, cab!’ and blac be indieated by
and IV in so far as they are above, and, by
so far as they lie below the projection-plane.
. vu .
varies between 0 and ; sin2y >0; 6 between
a
The sign of cot2y in the formula
\
In fig. 2 the globe-
the figures I, H, Hl
V, Vi, Vile Yili
In the first octant g
O and = sino >”.
a
(2) is consequently entirely
defined by the sign of the numerator of the fraction.
cot 2y = 0, if (sin 2y sino sin? V 0):
(1 — sin? V cos? v) — (1 — sin? V sin® gy) sin?s = 0.
If, with a constant value of o and J’, v increases, then the formula
becomes :
1 — sin? V cos? gy — (1 — sin? V sin? vy) sin? 6 =
s
= 1 —- sin’? o (1 — sin? V) — sin? V(L +
sin? 0) cos*@y . . (3)
( 10387 )
by the diminution of cos gy >O and becomes with g¢@ =
2
1 — sin? o (1 — sin? V)
cot 24 = — Sa ——_ = +,
; (sin 20 = 0) sin F sin® J
From this follows :
2 == 80° or O°
ee OL Oo we casa hts Ake ES Ae (A)
In fig. 2 the a-axis has been chosen as normal to the projection-
plane; it needs no further elucidation, that the plane that halves
Z Ash, here always indicates the direction of the vibration of the
quicker ray. If the pole of the secant-plane lies in the plane $6’,
then 7,, the angle between the longer ellipse-axis and the secant-line
rl
S: E(=«') becomes = , > so that the value y=O0=y, relates to
the short ellipse-axis.
if consequently the projection-plane is placed 1 to the negative
bisectrix, one finds with the help of (2) the angle, that the long
axis of the ray-velocity-ellipse forms with the secant-line of the
projection-plane and the secant-plane, if with a positive value of
cot 2y one takes the angle 2y, in the 3'¢ quadrant. Then 7q is likewise
an angle in the 24 or 4% quadrant, and has consequently, if we
oe
take the value << 57 a negative sign.
If in the Ist octant g diminishes from the point where with a
definite value of 6 and |"
1 — sin’ o (1 — sin? V) — sin® V (1 + sin? 6) cos? 9 = 0
then, in consequence of the increase of cos vy, the formula (2) has
negative values. With v9 =O becomes:
lL — sin? V — sin? o cos” 6 — sin? V
0 > cot 2y = —o = eee eee
7 (sin 20 — 0) sin OG smn” V (sin Ly = 9} sin 6 sin* J
x
If now one assumes for o all values between O and =H then it
a
appears, that cof 2yq_ becomes indefinite for
. u r
¢os 6 = sin V = cos{ — — V ).
2
The pole of the second plane lies here in the optic-axis. For
uw ; ; :
6 >>5 — V, cos* o — sin? V becomes <0, by which cot 2y obtains
a positive value, and 27 must be supposed in the 3" quadrant;
68
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1038 )
u - ‘ 5 Ne
cot 2y = + ®, Ya= = OO oe OL Cie i V cos? ¢ — sin* V becomes
>0, cot27<0 i. e. —o; the angle 2y in accordance with the
figure must, be taken in the 4' quadrant: 24, =0
x ress
For 5 >v>0 and cot2y<0 consequently 2. lies in the 4
Fd a
quadrant, and y,, in so far as one takes the value i > Yu >> 3
likewise in the 4 quadrant. In the 1st octant consequently is always
x ; 5
= GY) The same holds good for the oetants III, VI and
VIL, where the denominator of the formula (2) is likewise > 0.
To the value ya(y,c) in the first oetant correspond identical values
with (# + v), 6 in the II, (w~—y),—« in the VI", and (2a—»),
—o in the VII octant. Where the product sim 2yvsmo< 0
(cf. (2)), consequently, in the Im’, IV", Vand VII™ octant becomes:
ra P a 5
Oe at To ya(y,%) in the Ist octant correspond identical values
with a contrary sign with gy, —o in the V", (w—g), o in the 1["4,
(a + ¢), —o in the VII, and (Qa—y), o in the IV" oetant. In the
same way as has been done above for the octants I, III, VI, and VIII
one can determine the ratio between the sign of cof 2y and the
value of ya. The following {result is obtained: if the 2-axis stands
perpendicular to the projection-planes, then lies
if the octants I, III, V1, VII
with cot 2y > 0, 2ya in the 3' quadrant
cot 2y <0, 2ya in the 42 quadrant
a
in the octants II, 1V, V, VII gee)
with cot 2y > 0, 2ya in the 1** quadrant
cot 2y <0, 27a in the 2°¢ quadrant
In this way the orientation of the velocity-ellipse can be found
with certainty.
To find the angle which, in a diseretionary section, the long ellipse-
axis forms with the trace of a discretionary plane V7, we return to
fig.‘ 1. The plane V7, the pole of which is given by the coordinates
u— ~ILM, v= ~ M, is cut by S according to the line HO,
forming with OH an angle HOE=h. Now we found that
cos 6 cot a + sin 6 sin (U—¥)
vos (Y— 7)
coth =
( 1039 )
miwhieh y— —-— (CK — -
a
« =the angle between V and
~ t ha
cos O Cot (: 4 at
so that
cot h =
cos (¢ —et =)
the projection-plane = r +
sin © sii (¢ —n +
cos 6 tg YP — sin 6 cos (u—n)
sin (v— 1)
The angle between the long ellipse-axis and the trace of J” is
consequently given by
Z FOE= 7/7 HOF — / HOE= ya—h (6)
Fig. 3.
Fig. 5 gives the projection of a triclinic crystal, oligoclase of
aa
"
wU
9
(5)
Bamle '). If one measures y along the great circle ROQ from the
plane J/OM, positively opposite to the hands of a clock, o from
A
ROQ positively to the right, then the optie-axes
their bisectrices are determined by
v
A — 67°58’
B — 83°53’
a — 75°36’
ge 6°35!
!) Rosenpusen, Mikrosk. Physiogr. I. 2,
oO
— 44°58’
+ 47°9/
a 1°6/’
— 82°28)
342,
and
68"
Band
( 1040)
In AABM is AB=2V; AM—134°58'’ =) Beato
4 BMA=15°55’; trom this follows 2 V=93°10/30"; V=46°3515".
The extinetion-angle with regard to the trace of ?(001) in the
secant-plane J/(OLO) is caleulated as follows. If one takes 4 to the
biseetrix, Ox a plane £, corresponding to the projection-plane in
fiz. 1, one finds for the planes (= S) and P(=J’) the following
coordinates of the poles:
= JAW = 22 — 7# BoM =172°58'
e me,
C6 = = So Va = 1°6'
9
x
Wa, Cand) | = a
In order to find « and » one proceeds from the given equations:
M: P= 86°32': MW :1= 59°14’; P21 = 65°10"
From these one calculates:
ry 4 ¥
Z PML = 63°37; ZOMP =, — 63°37' = 26°23;
PP Oe 23 a oo O—al Ol Oke
so that now from AaMP can be found:
ee NOLS 3200 Sard «pa — PSS!) 0 eee cen (ic)
Farther one finds:
/MaP = 86°13'; p= /AaP = 22 —(/MaP + / Bam) =
=: Or 2 (86°13" 3.792") = 86°45.) ae ee
The planes M and F (1 20) cut each other according to the line
OR; with regard to this line the extinction in Jf amounts to an
angle y given by (ef. (2)):
1 — sin? V cos? 7°2' — (1 — sin? V sin? 7°2!') sin? 1°6'
cob Jy = - --
; sin 14°4! sin 1°6!' sun? V
lq cot 2y = 2,28980 (—).
and as the pole of J/(y=172°58', c=1°6') lies in the II=¢ octant
2yq must be taken in the 2°¢ quadrant, so that
2yq = 180° — 1738"
a
jo — 209i 20°51 a
The angle that the trace of P makes with the direction OR is
found from (5) :
cos 1°6' tg 11°53'20" + sin 1°6' cos 86°13!
cot hh = == : —
sin 86°13!
ly cot h = 9.32678 (—)
[xa opal UR eoetrsee Poneratiemides (0 eB Gc (9)
( 1041 )
The angle between the long ellipse-axis and the trace of ? is conse-
quently given by (cf. 6)
Vag = 8 9r c el Sol 16a aN St —— 12°08"
Rosrnpuscu gives (vide above) for the same mineral as calculated
value (—) 12°16”.
The method of calculation followed above. is the base for the
graphical method, according to which, in a discretional crystal-section
the extinction-angle with regard to the trace of a diseretional-plane
can be determined from the size of the axis-angle. One proceeds,
for domg so, from the coordinates w,r of (J) and ¢,6 of (S
If we take the oligoclase discussed above, we find, in the way
as was explained last time, the value 4 in the diagram for
== 4 / MaP =176°13', 6, =1°6’. As
7
ee
Ee
War
Vy)
WEL Li oe =
Vig. 4
appears from the scheme of the /-diagram') a value 4 = — ea corre-
sponds to a secant-plane (yv, = 22, 7, = 0); one finds consequently
likewise in our case for 4 a value, deviating but little from —- 78°.
To determine the optic extinction with regard to the fictive trace of
the plane # (1 ¢Q), one uses a second diagram, which has been cal-
culated with the help of the ratio (2), and gives for a definite axis-
angle the value y as f(@,«). In fig. 4 the y-diagram for = 30°.
is represented; in the hatched octants (II, IV, V, VIL) y has a positive
value, in the others a negative one. For a further explanation of
this diagram we may refer to what was said above about -the
signification of the ratio (2) and to a former communication in which
a similar diagram was discussed *). The y-diagram for Vo = 46°35/
“Ss none These Proc XIII, p 731. fig. 4—5.
2) These Proc. X, p. 375 et seq.
( 1042 )
“ . . , T)ONQ/ a s ons
furnishes for gy, = “AaM = 172°8’ and o,= > — / Ma =1°6
CI
about the value y= - 89°50’. Thereby the value u=y—-h=
= — 120 isitound:
Per contra the axial angle 277 ean be determined, if one knows
the secant-plane S(v,6), the extinction uw with regard to the trace
of a known plane J” (u,7r) and the direction of the extreme ray-
velocities.
In fig. 5 the amphibole-crystal is represented, ef which in the
previous communication’) with the help ef the apparent angles
between the prism-planes and the clinopinakoid the orientation was
determined. The angles «, = 55°50’ and «a, =—62°5’ are here
inclosed either by the planes m,:m, (= a«,) and 6,:m,(=a,), m,
taken as equatorplane, or by m,:m,(=a,) and bs: my (= apne
considered as equatorplane*). For the place of the poles of the
secant-planes |S, and S, found, it does not make any difference,
whether mz, with its pole D, or m, with its pole / is taken as
equatorplane, as this oceasions only an interchange of s, and s,. If
one takes m, as equatorplane, then lies
Seewvith et vO L300)
Ce ise o 025)
So WIth tO ep OK == —' 3555!
Oe Ks = = 13,0550)
1) These Proc. XIII, p. 728.
2) The complications resulting for the orientation from the ecrystal-symmetry will
be treated in a further communication.
~
( 1043 )
The extinction observed under these circumstances amounts with
regard to the trace of m,(m,) to w= — 6°. The plane of the optic-
axes OA lies // (010); be further the angle ¢:¢=10°, then the
axial-angle can be calculated.
For the poles s, and s, one finds by calculation the following
coordinates with regard to the plane-systems OA, /) (= projection-
plane) and OA, C (4 bisectrix c):
LAB —ca= 108°15'38' PAT Voie aa 2!
= Gs, = Or, == A4Ca ee — Tx = Ore = 44°35/28"
AS Oo = M684 3113" Co ACs) 0 '¢—= — S14 612"
pg == Ole 40°44'20" PS Si AGES aoe
For the pole 7’ of the plane m, one finds from u, = ~ ABDT =
— in | 2inooe. w—O) by = calculation pe 2 7 28° 16152",
DP, = —- 8°49'35". The angle between the trace of m, and the fictive
trace of C is according to (5) for the secant-plane SS,
cos 6'. tg Ve — sin 6'¢ C08 (Oe — Me)
CO — ——____ -
sin (Q ¢-—Uc)
cos 40°44'20" tg 8°49'35" — sin 40°44'20" cos 88°31'21"
: sin 88°31'21" rw
from which 4, = 84°14'20"
and for S, by:
— cos 46°53'35" tg 8°49'35" — sin 46°53'35" cos 69°57'6"
sin 69°57'6"
from which h, = — 69°13'20",
so that according to (6):
Np h
one finds for S, (II"¢ oetant) :
y'o =u 4- h, = — 6° + 84°14'21:” = 78°14'20"
and for S, ([V‘ octant)
ee Op OO clts 20 key ella 20
From the diagram fig. 4 it can immediately be seen, that y for a
secant-plane in the IV" octant can never become < 0 and conse-
quently S, does not correspond.
Now is according to (2):
hy 1 — sin’ V cos’ 9 oj (1 = sin? V sin’ y) sin” 6
sin 2y sin G sin? V
sin” V (cot 2y sin 2y sin 6 + cos? vy — sin? v sin? 6) = 1 — sin? 6
Cos? 6
Se SMTA Se ae G0)
TrGOry Ra OS ee , then 27 lies in the vicinity of
O° or +2. In (10) cot 2y furnishes then, with differences of a few
minutes, which cannot be measured with certainty in ordinary cir-
cumstances, already values differing so much from one another, that
the final result is greatly influenced by it. If we take e.g. the feld-
spar of Bamle discussed above. For y, was found the value 89°51’
whilst from the caleulation according to Rostnxpuscn would follow
Hip Oo 43".
The difference between /y cof 2yq and ly cot 2y'q is
228100 —- 2.00478 = 0,27622,
so that here an observation-mistake of 8’ counterbalances 8°35/
with 7 = + 45°. Consequently one calculates from the value, given
by Rosrnsuscw for the extinction, with regard to the trace of P (O01)
in the secant-plane M (O10), w= y', —h= —12°16’ (instead of
— 12°8’), a value for V = 55°50’ (instead of 46°35’). The pole of
the secant-plane J, fastened to the axes-plane AG (comp. fig. 3)
and the plane 1a, lies with » = 172°58’, o=1°6’. So the result
was to be expected.
Crystallography. — “On the determination of an unknown plane
from its traces in two orientated crystal-sections.” By J. ScHMUTZER.
(Communicated by Prof. C. E. A. Wicrmann).
(Communicated in the meeting of lebruary 25, 1911).
If one calls the coordinates of the pole of an nnknown plane P?
(erystal-, cleavage- or twinning-plane) w and py, if two known secant-
planes S, and 5, are given by the poles s, (9,,6,) and s, (Q,, 4,)
and if further the angles, which the trace of P in these planes
(1046)
makes with the secant-line between secant-plane and projection-plane
(S: E) be suec. 4, and h,, then
cos 6, ty 1 Y — sin 0, cos (9, — 0)
cot h, =
sin (0, — 7)
os G, tg »v — sin 6, cos (0, — A)
cot h, =
sin (0, — #)
coth, sin(o, — 4) + sind, cos(e,—ft) _coth,sin(g, —w) + sino, cos(o, —u)
o— ~— + ~-—+_*4__~ (1)
COs O, COs O,
from which :
cos 6, cot h, sin (Q, — wt) + sin 6, cos (Vv, — ft)} =
cos O, ‘cot h, sin (v, — fa) 4- sin 6, cos (v, — K)j
which worked out produces :
COs 0, AS ae COs, — SING, sinY Meng (coth, 08 VU, — SING, 810» 4) Pe
HO Se are SSS SSS SS ee (2)
With an augite-crystal the planes m, (110) and m, (110), being
fixed to the projection-plane / (.L¢; ¢:¢=45° 18’) and to the plane
1 4H, laid through the normal of m, are determined by px, = 0,
v, = 29° 20’ 55" (m,) and py = 1129227 34") »,==29° 20755! (Gnas
m,:m, = 92°48’. In fig. 1 the left section answers to the secant-
plane S, (gv, = 36° 30’, 6, = 47°), the right one to S, {v,= 220°30’,
6, = 79°); the traces of the planes m,, m, and of the twinning-plane
« of the interpolated lamel make in these sections with the secant-
line SS: # the angles 4, = — 70° 34’; h, = —78°4’, h, = 89° 24’
and h', = — 37°10’, h', = 66° 4’ and hi’, = 13°30’. With the help
of the values @,, 6,, ¥,, 6,, NM, and a one finds from (2) for « the
value f= 56°20" and from (1) ry = 45° 8’. The plane P is consequently
1 (100) which is theoretically determined by eo = 56117!
=
and. p10 3 ol a
( 1047 )
Anatomy. — “Remarks on the reticular cells of the oblongata in
different vertebrates.” By J. J. i. D. Baron van Horvenn.
(Communicated by Prof. LL. Bork.)
(Communicated in the meeting of January 28, 1911).
The reticular cells in several mammals have been examined and
described, and about some birds we have minute information from
Casa’), while Mespac *) also gives excellent descriptions and illustrations
of the large reticular celis in one species of bird (Gallus domesticus).
In the reptiles. however, where the reticular cells are singularly
conspicuous and characteristically arranged, these cells have never
been described, nor have we any information of importance regarding
the amphibians ard various species of fishes *).
A comparative study of the reticular cells has never been made,
although these elements exhibit great differences in the vertebrate
stem together with points of resemblance. Even in animals of the
same Class noticeable differences are found.
It cannot be denied that, as lone as so little is known with
certainty about the nature and significance of the reticular cells, if
would be somewhat rash to make comparisons, since the possibility
of dissimilar quantities being compared with each other is not
excluded. In my investigations I have confined my attention princt-
puliv to the largest reticular elements, because these are the most
fit for comparison. Still less is known of the small reticular cells
than of the largest. A sharply defined boundary of the larger reticular
cells from the smaller is, however, not always possible as yet. Besides
the large reticular cells, therefore, | have traced the smaller ones
also as much as possible, althongh the chief aim of my research was
the arrangement of the larger elements. I have examined series of
frontal sections coloured after VAN Grkson or with carmine.
The animals which I examined were:
one cartilaginous fish: Raja;
one ampbibian: Rana:
!) Contribucion al Estudio de los ganglios de la substantia reticular del bulbo.
Trabajos del laboratorio de Investigaciones biologicas. Tomo VIL fasc. 4°. 1909.
2) Bijdrage tot de ontwikkelingsgeschiedenis van de structuur der hersenen bij
het kippenembryo. Inaugural Dissertation. Groningen 1909.
3) Special mention must be made of the large cell elements of the oblongata
in the Cyclostomes, lately described by Trersakorr Whether the large Mullerian
cells of the Cyclostomes are to be classed with the large reticular cells of the
bulb of other animals is not certain, but ihere is much which pleads for a homology
(Cf. Trersaxorr: Das Nervensystem von Ammocoetes. Il. Gehirn. Archiv. fiir mikro-
skopische Anatomie und Entwickelungsgeschichte. Vol. 74, 1909).
( 1048 )
iwo reptiles, Alligator sclerops and Chelone midas ;
one bird, Ciconia alba;
and several mammals, viz. :
two Marsupials: Macropus robustus and Didelphys;
two Rodents: Cavia cobaya and Lepus cuniculus ;
one Ungulate: Equus caballus
and one cetacean: Phoeaena communis.
Raja.
In viewing a series of frontal sections through the oblongata of
Raja, one observes everywhere the large reticular cells arranged fairly
uniformly along the lateral and ventro-lateral border of the fasciculus
longitudinalis posterior. Only in the caudal part of the oblongata,
on the level of the extrance of the X" roots, is a different form to
be found owing to the reticular cells here being greatly massed in
the raphe.
The reticular cells of the bulb of Raja form one continuous series.
They are not, however, distributed equally over the bulb; on some
levels they are to be found more massed, so that one might speak
of reticular nuclei. The reucular cells in Raja can be divided — on
descriptive anatomical grounds —- into 3 groups, viz.: 1s, a candal
group, occurring on the level of the extrance of the X roots, Qad |
a group occurring on the level of the entrance of the VIII roots,
and a 3 group, which comprises the series of reticular cells front-
ally from the VIII’s entrance. For the sake of convenience these may
be termed nucleus reticularis inferior, medius, and superior.
Fig. 1 represents a more caudal level, Fig. 2 a more frontal level
of the X roots. The accumulation of cells between the fase. longit.
post. and the base can be seen, with a marked raphe nucleus (figs.
1 and 2:a.) and wings which stretch out sideways, wreath-like,
underneath and along the border of the fase. long. post. Some of
these cells le fairly dorsally, lateral from the fase. tong. post. (Figs.
1 and 2:4). Other cells lie more ventrally in the formatio reticu-
laris. (Figs. 1 and 2:c). A few smaller reticular cells lie rather
far laterally. (Figs. 1 and 2:/). The reticular nucleus of the Y
region can be detined caudally as well as frontally. In the caudal
direction the number of cells gradually decreases both in the raphe
and in the formatio reticularis, while the cell-type also grows
smaller. Frontally from the entrance of the Y roots the number of
reticular cells likewise decreases, so that between the .Y and VIII
root-entrances a region occurs, where but few reticular cells are
found. On the level of the entrance of the octavus another massing
( 1049 )
of reticular ceils is found (Fig. 8). There 6—8 large cells per section
are to be found in each bulbus-half, arranged round the ventro-
lateral border of the fase. long. post; the most dorsal lie almost in
the middle of the dorso-ventral diameter of the bulb (Fie. 3: b.),
and the others medio-ventrally from there, more towards the lower
border of the fase. longit. post. (Fig. 38:¢.) A few smaller cells have
a more ventro-lateral position. — In the raphe only a few smaller
cells occur.
Frontally from the VIIl-entrance the number of large reticular
) per section are found. (Fig. 4: 6. and
cells again decreases, and 3
Fie. 5 b and ec.)
The position is almost the same as on the VIII level. The ‘small,
ventro-laterally situated cells are also seen again frontally from the
VIIE entrance, the most clearly jlist behind the V root entrance. Fig.
4 shows a section through the motor V nucleus. Fig. 5 a section
frontal from that. With slight variations in the number of the cells
the series of reticular cells continues as far as under the frontal
boundary of the Bracchia cerebelli and, where the Bracchia dis-
appear from the sections, it is seen only sporadically. ')
In the raphe merely a few smaller cells occur frontally from the
VUUs entrance.
Neither on the VIIT level nor frontally from it is there any trace
of a raphe nucleus proper.
Rana.
In the amphibia, where the arrangement of all the cells remains
periependymal, the making of a distinction between reticular cells
and other cellular elements is too difficult to allow of details being
learned about their topography.
Alligator Sclerops.
The large reticular cells in the oblongata of the alligator can be
divided into 2 principal groups. The most caudal group lies on the
level of the entrance of the X roots and contains a reticular nucleus,
capable of being fairly sharply defined. This nucleus commences,
caudally in the oblongata, as a little cluster of small reticular cells
in the raphe and under the fase. long. post., while a small group
of cells is also to be seen on caudal sections ventro-laterally in the
1) More frontally in the midbrain again a larger amount of reticular cells occur.
This is, however, beyond my scope.
( 1050 )
formatio-veticularis, partly polygonal and partly somewhat spindle-
shaped. According as one examines frontal sections, more and larger
reticular cells will be seen, On the level indicated by Fig. 6°) the
nw Xe
a
Fig. 6. Alligator selerops.
reticular nucleus has attained a considerable size. Also the lateral
nucleus /, is well developed on this level.
Fig. 7. Alligator sclerops.
1) In considering the drawing it must be borne in mind that the oblongata of
the Alligator is markedly bent and that the direction cf the section has been
chosen perpendicular to the base on the level of the VIl-root, so that the caudal
sections are not perfectly perpendicular to the longitudinal axis of the oblongata.
In Figs. 6, 7, and 8, the dorsal half represents a more caudal leve! than the
ventral half.
( 1051 )
Slightly more caudally than is shown by Fig. 6, the hypoglossus-
cells (or the anterior-horn cells; a sharper distinction between them
cannot be made by my method) take a more ventral position, and
can only with difficulty be distinguished from the reticular cells
which lie in the lateral border of the fase. longit. post.
Fig. 7 represents a section which passes through the entering
X roots. The same nucleus with large cells as in Fig. 6 is met with
here, though on a more frontal level. The large cells can be seen
lying partly in the raphe, partly in the formatio-reticularis, spread
wreath-like in a ventro-lateral direction, while a small group lies
more or less isolated somewhat more ventrally. (Fig. 7c.) Laterally
in the periphery a nucleus can be seen (Fig. 7 /,), which I cannot
determine with certainty to be the continuation of the lateral nucleus
(/,) of Fig. 6, since nucleus /, decreases frontally, so that on a level
between Fig. 6 and Fig. 7 very few cells lie there which cannot
be distinguished from the remaining scattered cells of the formatio
reticularis.
The large reticular cells on the level of the VIII root entrance
can be taken together in one and the same group with those occur-
ring more frontally. This group is easily distinguishable from the
more caudal reticular nucleus of the vagus region.
Fig. 8. Alligator sclerops.
Fig. 8 represents a section through that part of the oblongata that
may be regarded as the transition or boundary region between vagus
and octavus region. On several of the sections only one single large
reticular cell is to be seen on this level; in Fig. 8, one can be seen
in the border of the fase. long. post. (6). Ventrally in the raphe (a)
( 1052 )
and next to it (¢), between the fase. longit. post. and the base, a
laree number of smaller reticular cells are seen. Situated ventro-
laterally on the periphery ave a group of polygonal cells (Fig. 8, /,),
which lie dorso-medially in one straight line with two other groups.
The most dorsal of the three groups contains motor VIL. root-cells,
the middle one is very likely a more ventral VII. nueleus. It is
highly improbable that the most ventral of the three (/,) is a
VII. nucleus, as has already been pointed out by Kappsrs'). This
last group forms the continuation of group /, of fig. 7. I consider
them as reticular cells.
On a level slightly more frontal than is shown by fig. 8, more
large reticular cells are again seen. Fig. 9 represents a section
passing through the VIII. root-entrance. In the raphe large cells can
nowhere be seen in sections taken more frontally than tig. 8, though
in fig. 9 a few small cells can be seen in the raphe. By this faet
too the reticular nucleus of the vagus region is distinguished from
ne YT
Fig. 9. Alligator sclerops.
the reticular cells of more frontal regions of the oblongata. The
arrangement of the large cells next the lower border of the fase.
longit. post. (6) and more ventrally (c) medially from the large oliva
superior is seen in the figure.
I still wish to eall attention to some very large polygonal cells
occurring in the grey matter of the radix descendens nv. V. and to
1) See also Verhandel. Kon. Acad. y. Wet. 2de Sectie, Part. 16, No. 4. (Map
E. and page 64).
( 1053 )
tlie fact that a few of these lie very peripherally or laterally in tha
erey matter. Immediately above the point of the oliva superior and
lateral from the olive le some smaller cells.
The series of large reticular cells of the octavus region is continued
frontally without interruption. In Fig. 10, which represents a section
de WIT
KE
x
chat . RES
. SAE 5 \
ori ‘Nes Sed,
~ ss l=
a
t= ~
ne. nek Fe
OC sup
Kig. 10. Alligator sclerops.
passing through the caudal part of the motor V. nucleus, the large
reticular cells lie as a circumscribed group iu the middle of the
Fig. 11. Alligator sclerops.
69
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1054)
diameter of the bulbus. Laterally from it a dorso-veutrally stretched
nucleus is seen which is probably a ventral motor V'" nucleus
(IXApPERS) *).
Fig. 11 represents a section through the entering V root. The large
reticular cells have partly kept their position more in the middle of
the formatio reticularis, but partly also lie more ventro-laterally,
stretching out to the upper side of the frontal rest of the olive, which
is seen on this level, as in fig. 10, as a small mass of grey matter
(indicated in the figure by dots) with one single little cell. Medially
from the frontal rest of the olive, a small group of little polygonal
cells occur regarding which [ do not venture to say whether they
belong to the reticular cells or to the grey substance of the lateral
lemniseus (fig. 11.7).
In the raphe there is a nucleus of small cells, which seems to
have no connection with the other cells of the formatio reticularis.
(fig. 11, nr. parvoe. sup r.); [ should like to give this nucleus the
name of nucleus parvo-cellularis superior raphes in contrast to the
cluster of large raphe-cells, which form part of the reticular nucleus
of the vagus region. In Fie. 11, under the angle of the ventriculus
quarius a group of cells can be seen which in position agree with
the nucleus loci coerulei*) beginning more frontally in mammals.
6 gua p \
ne:
>=
Nig. 12. Alligator sclerops.
1) Especially from a comparison to chelone midas this is probable; in chelone
a similar nucleus occurs at this place, which frontally coincides with the motor
V-nucleus. See Verhandl. der Kon. Akad. van Wet. 2de Sectie, Part XVI N°. 4,
pages 39 and 40. Map.I..
2) As in the lower mammals this nucleus is not pigmented here,
(2055. )
More frontally from Fig. 11, we again find a less lateral arrangement
of the large veticular cells’ and the number met with per section
also. diminishes. Fig. 12 represents a section through the praetrige-
minal region of the oblongata of the Alligator. The section here
shown passes through the posterior pole of the tubereulum quadri-
geminum posticum and also intersects the TV nucleus. The arrangement
of the large cells, as oceurs here, in the middle of the diameter
of the bulbus, continues frontally to the end of the series of reticular
cells, i.e. to behind the II] nucleus, where the large reticular cells
are sporadic The raphe nucleus with small cells, which can also
be seen in fig. 12, ceases on nearly the same level as where the
large reticular cells become sporadic. These raphe-cells maintain
a more independent character with regard to the other reticular cells.
Chelone Midas.
Chelone differs in many respects from Alligator. In the caudal
part of the oblongata it shows some resemblance to the latter as
regards the appearance of the reticular cells. Nor is the praetrigeminal
region markedly different from that in Alligator. On the level of
the entering VIIL and V roots, however, an entirely different aspect
is presented. Following the same order as I took in examining the
other animals I can state the following details about the reticular
elements of Chelone: On the level- of entrance of the X roots, one
reticular nucleus is found, which resembles the nucleus found in that
region in the Alligator in so far as the large reticular cells are arranged
in the same way in the raphe and along the lower and side border of
the fase. long. post. In Chelone, however, no reticular cells are spread
so far laterally in the formatio reticularis. Also the groups /, and /, of
Alligator (PI. 6, 7 and 8) are wanting in Chelone. The reticular group
of the vagus region is sharply limited orally, owing to the fact that,
on the level of the extrance of the VIII, large reticular cells occur
only” sporadically and but a few smaller reticular cells are present
there‘). On the level of the motor trigeminus nucleus on the other hand,
there is a cluster of large reticular cells, not only alone the lower
and outer border of the fase. long. post., but also in the raphe,
which [ did not find on this level in other animals. (See fig. 13).
On the level of the caudal half of the motor V nucleus the large
cells are even found principally in the raphe; on the level of the
frontal half of this nuclaus, however, there are as many lateral in
1) The ne. Deiters is well developed. | found no oliva superior.
69*
Fig. 18. Chelone midas.
the bulb as in the raphe. Orally from the motor V nucleus the large
reticular cells lie almost in the middle of the diameter of the bulbus,
while in Chelone as in Alligator, a raphe nucleus of small cells also
occurs in the frontal part of the oblongata (2c. parrocell. sup. raphes)
which nowhere shows any connection with the other reticular cells.
Ciconia alba.
I examined only one bird, viz. Ciconia alba, in the study of which
a series of frontal sections coloured after VAN Gipson was used.
[ found the reticular cells for the most part agreeing with the
descriptions, which CasaL gives of these elements in birds. For the
details, therefore, I refer to his description. [| wish to touch merely
on the following points.
The large reticular cells do not extend in Ciconia so far caudally
‘in the oblongata as they do in the lower animals [ have described.
If the sections in frontal direction be followed, only smaller reticular
cells are first seen along the lower border of the fase. long. post.,
and more laterally in the formatio reticularis. Then a few very
small cells also appear in the raphe. More frontally the reticular
cells become more numerous and include larger cells. The cells in
the raphe remain somewhat inferior in size to the more lateral cells
in the same section; this relative size continues to the level of the
VII} root-entrance, where giant-cells occur also in the raphe. Con-
© A057 »)
sidering that the transition is gradual, however, the boundary where
these giant-cells begin in the raphe cannot be sharply defined,
Ne Sons .
x ne WUT
Maret
Ne meta
c
Fig. 14. Ciconia alba
Fig. 14 represents a section passing through the oblongata of
Ciconia, slightly frontally of the NIP nucleus or through the frontal
pole of that nucleus"). In this section the connection of the laterally
situated giant-calls with the raphe cells which are rather smaller,
can be observed.
Caiat describes on the level of the vagus roots only the giant-cells,
which lie more laterally in the formatio-reticularis, but neither
mentions nor illustrates anything of raphe cells on this level. The
large cells lying lateral from the vagus region are collected by
him into a separate nucleus and distinguished from the remaining
more frontally situated cells by reason of a peculiarity in the course
of the axis cylinders *).
By my method of research | was not able to find any such, or
similar, distinction; according to VAN Gibson preparations the reticu-
1) Whether the dorsal group of cells in the border of the fasc. long. post. ave
sull motor XIL root-cells, | do not venture to decide.
2) The cells of his “nucleo magnocellulur inf.”, 1. e. the reticular cells lying
in the region of the vagus-root, send their axis cylinders for the greater part to the
contra-lateral bulbus-half, after decussating dorsally in the raphe, while all the
other more frontally situated reticular cells send the axis-cylinders chiefly caudally
in the yia homolateral (in, or next, the fase, longit. post.) or caudally and fron-
tally after bifurcation.
( 1058 )
lar cell-massing of the vagus region of the oblongata continues
unnoticed in that of the octavus region.
In fig. 14 there is visible under the Radix spinalis nervi V a
finy group of small cells (/), which form the frontal pole of a
circumseribed group of small and medium-sized cells, the meaning
of which | cannot conceive.
The cell elusters in the caudal part of the oblongata of Ciconia,
which in position agree with the olivae inferiores of mammals, and
in the lateral part of which polygonal cells are found connected
with the vetieular elements, are no longer present in fig. 14.
For the further deseription of the birds I refer to CaJsat’s excel-
lent work. The basal position of a large part of the reticular
elements on the VII and V_ level is’ particularly striking in his
drawings. I found it so in Ciconia also, and will merely mention
still that the ne. parvocellul. sup. raphes also oeceurs in Ciconia.
Mammals.
In the mammals which I examined | found the large reticular
cells in the oblongata arranged in a way which principally is the
same in all of them. I only found gradual differences and some
differences in the relationship of details.
The smaller reticular cells form groups of greater or less size
which generally cannot be sharply defined, though where I sueceeded
in doing so, L received the impression as if the groups of smaller
reticular cells also agree in principle with each other in the mam-
mals. In how. far the differences which occur are connected with
other differences in the formation of the oblongata, 1] have not
been able to decide; to bring out all those details I should have to
vive a complete series of drawings of each animal, which would
lead me too far. | shall therefore content myself with describing two
animals in which the peculiarities of the large reticular cells were
the clearest, viz. the giant kangaroo (Macropus robustus), the caudal
part of which I shall describe, and the horse, of which T shall
illustrate the frontal part on account of the peculiarities being the most
pronounced there. ee 9 i
The large reticular cells are found in Macropus and in the horse
specially massed in two places: one cluster lies in the vagus and
octavus region and attains its greatest development at the caudal
boundary of the VIIL root-entrance, the other lies on the level of the
motor V nucleus.
Fig. 15 shows a section passing through a caudal level of the
( 1059 )
oblongata of Macropus; one of the X roots is visible in the figure.
he Jers KX heVT Ne fie n pest lat
Pee pro
ne Sta.
Wa
mh AIL
Fig. 15. Macropus.
Hoke
Fig. 16 represents a section through the caudal boundary of the
VIII root-entrance in the same animal.
Fig. 16. Macropus.
On the VIII level distinct giant-cells are to be seen in the ‘aphe
as well as more laterally in the formatio reticularis. According as
1060 )
one proceeds more candally, however, the (ype of cell becomes smaller,
in the raphe rather sooner than in the formatio reticularis.
Fairly far caudally there continues to be a clear connection
between the raphe cells and the reticular elements situated) more
laterally,
In fig. 15 this connection is still visible. The largest reticular cells
which occur here are, however, no longer giant-cells.
In fig. 15 a part of the ne. funiculi lateralis can still be seen,
which nucleus is well developed in Macropus, and attains its greatest
size on a level caudally from fig. 15. In how far there is a connection
between the elements of this nucleus and the other reticular cells *)
| cannot make out. This also applies to the series of cells lying
laterally adjacent to the oliva inferior, and there are also doubts
about the small group of cells situated ventrally against the radix
descendens V as also about the small series of cells medio-dorsal from
them, also visible in fig. 15; in this last case because they may
for a part contain ventral motor root-cells. In proportion as these
small groups of cells (also the ne. funic. lat.) may be classed together
with the rest of the reticular cells, a different picture of the spreading
and arrangement of these elements will naturally be obtained.
Peculiar in any case is the way in which the reticular cells,
arranged, more or less, in rows, are spread from the raphe in a
ventro-lateral direction in undulating lines, laterally and ventro-
laterally through the formatio reticularis. They form an arch over
the oliva inf. and where the ne. facialis appears in the sections
(fig. 16) they extend to that nucleus. Where the VIL nucleus ends a
more lateral spreading can be seen.
As long as so little is known about the nature and the significance
of the reticular cells, a rational division into groups is impossible.
That the various writers differ in their division and nomenclature of
the reticular cells seems to me very comprehensible *). In my opinion
it is not desirable for the present to make any divisions into groups
1) Marpure, in his atlas, sometimes calls the ne. funic. lat. also ne. retic
lateralis. (See: Microscopisch-topograph. Atlas der menschlichen Zentral Nerven
systems).
2) The reticular cells lying round the XIL roots were taken together by KOLLIK ER
as we. reticularis diffuses: he mentioned them “besonders in den lateralen Theilen
der formatio reticularis” and medially “bis gegen die Rapbe hin.”
The cells lying medially from the XIL roots are considered by OBuRSTEINER as
ne funiculi anteriores, and by MIssLAwskt and vAN BECHTEREW as 7C. respiraloris ,
The large cells occurring on the level of the VILL entrance and caudally from
that, have been described by Ronier, and are termed by most writers 7c. centralis
inferior ROLLER.
( 1061 )
which cannot be sharply defined from each other. Even the collection
of the giant-cells, of the octavus and of the rather more caudal region
ito a separate nucleus, although these cells are clearly larger than
the largest reticular cells which occur in the vagus-hypoglossus region,
seems to me to be undesirable at the present time. The transition
in the size of the cells is after all a eradual one, and whether here,
as in birds, by reason of a different course of the axis-cylinders, the
cells of the vagus region of the oblongata have to be distinguished
from those of the oectavus region or not must be decided by further
histological research.
By my method of research I could not make distinctions based
on cell-structure differences between the cells; IT must therefore
refrain from passing an opinion. *}
If we collect all the reticular cells of the caudal half of the oblon-
gata —— caleulated to about the frontal boundary of the VILL root-
entrance —— into one nucleus, we might term this secleus retienlaris
inferior, and to indieate that the cells extend to the raphe and partly
collect there, we might distinguish a pars raphes anda pars lateralis ;
and possibly also include the ne. reticularis funiculi lateralis.
On a level slightly frontal from the VIIL 100t-entrance the number
of reticular cells decreases, fo increase again on the level of the
V nueleus. On the level of the motor Vo nucleus and in more frontal
parts of the oblongata [| no longer found any giant cells in the
raphe except sometimes (Macropus) a very few on the level of the
most caudal part of the mot. V nucleus. Cells are indeed found in
the raphe which agree with the ne. pontis and still further frontally,
immediately behind the corpora quadrigemina, a raphe nucleus of
small celis. To these cells, which have probably another origin and
meaning, IT shall return Jater.
The large reticular cells in the oblongata of the trigeminal and
praetrigeminal regions of the mammals, with the exception of phocaena,
showed a peculiarity in their arrangement which was not equally
conspicuous ino all. The cells are divided more or less clearly into
{wo groups, one of which remains lying move dorsally in the bulb
While the other has shifted in a ventro-lateral direction, coming to
1) The large reticular cells which occur in man on the caudal part of the VILL
rool-entrance, are counted by Jacossoun as belonging to two reticular nuclei, which
lie partially through each other: his ne. giganto cellularis formationis reticularis
and lis ne. motorius dissipatus formationis reticularis. This distinction he makes
solely on the ground of cell-structure differences, while he states that the cells of
the nc. niot. dissip. fr. are in general smaller than those of the we. NG. fir;
although they sometimes attain the size of the latter.
( 1062 )
lie against the lateral lemniseus. In the horse [ found this displace-
ment the plainest; there the reticular cells even lie partly between
the fibres of the lateral lemniscus.
In Macropus these two groups are still clearly connected ; in other
animals, e.g. the rabbit, I found a relationship whieh is medium
between the horse and Macropus.
Figs. 17, 18 and 19 represent sections through the oblongata
of the horse. The level of the sections is sufficiently clear in the
drawings.
The large reticular cells are seen to be split into two groups.
The ventro-lateral group maintains its position against, and in, the
he. 2eree|
Bech terce 2
Fig. 17. Equus
border of the lateral lemniscus. Where, on a more frontal level,
the lateral lemniscus lies more dorsally in the section, the reticular
cells also lie more dorsally in that section (cf. Figs. 18 and 19).
In figs. 18 and 19 L have indicated the boundary of the nuclei
pontis by a dotted line. In the vicinity of the raphe a bulging of
the nucle: pontis into the oblongata can be seen on fig. 18, indi-
cated by the dotted line. In the horse, the cells of this group cannot
be sharply defined from the other cells of the ne. pontis. In some
animals, however, e.g. the rabbit and especially Phoecaena, the cells
( 1063 )
of this dorsal group are so distinctly different from the other ne.
pontis, and send out such peculiar off-shoots in lateral and dorsal
» ;
/ fe :
o /
. 4 vf
/
S Yor ae :!
4 : ;
, 48 PRE Ae uy ;
g — Sta UN i A (1) aN
ee Sees
leh, ;
Bechbercar
ip CE Sop
Fig. 18. Equus,
NC leon €
Ve PME. ———-«
f00p. Capr
7
be
Fig. 19. Equus.
directions that this cell-group has probably a special significance and is
worthy of a separate name. The name of ne. reticularis tegmenti
given to it by v. BrecurgrEw is not, in my opinion, a very happy
choice, as it might be confused with the other reticular cells in the
fegmentum on the same level. | would propose to name this group
after him who first deseribed these cells, viz. ne. reticularis Bwcn-
TEREW, in order to avoid a regional division for the present. Whether
( 1064 )
the small group of cells in the raphe in’ fig. 17 belongs to the
ne. retic. Buonrerew, | do not venture to state with certainty. They
are separated caudally from the pars raphes nuclei reticularis infe-
riores, but frontally are connected with the ne. pontis and the ne,
refic, Brournemw. Their dorsal position in the raphe renders a con-
nection with the ne. Bronwrurew more reasonable, while the extension
caudally from the pons makes it not probable that they belong to
the nuclei pontis*).
Frontally from the ne. retic. Brenrurnw there is a nucleus of
small cells (fig, 19) which ought probably to be distinguished from
the other reticular cells, and is very possibly homologous to the ne.
parvoe. sup. raphes of the reptiles, at least to the frontal part of
this nucleus. Vor Brenrrruw described this first in man as ie. ce-
ralis superior; later he renamed it ne. centralis superior medialis
s internus, or simply ne. medialis to cistinguish it from the large cells
occurring laterally in the formatio reticularis, which he calls ne.
centralis sup. lateralis.
Let us now return to the large reticular cells. Frontally from
Fig. 19 we see the large reticular elements soon take up a more
circumscribed position, almost in the middle of the bulbus-half, owing
to the disappearance of the ventro-lateral cells from the sections.
Somewhat farther frontally still we see that the more dorsal large
reticular cells also become fewer.
The whole series of these large elements of the trigeminal and
praetrigeminal region of the oblongata [I would collect under one
name, viz: nucleus reticularis superior, which may consist further
of a ne. superior centralis s. dorsalis (b.) and a ae. superior ventro-
lateralis (b.%).
This ne. sup. dorsalis s. centralis thus coincides with the ne. centralis
sup. lat. (Brcourernw), while similar to my ne. sup ventro-lateralis
would be the ne. tegmenti lat. deseribed by KGLEIKER in man as
occurring between the Lemmniscus lat. and the Braeehia anteriora ’)
Herewith IL conclude the description of the arrangement in Ma-
cropus and Equus which on an average is the same in other mam-
mals. The relations found in cavia, rabbit, cat, and man were in
principle little different from those mentioned above.
Only in Phocaena | found a more primitive arrangement, as I did
') In a deaf born eat. the nuel. ret. Becht seemed to be reduced.
*) | suppose that the nucl. paralemniscalis inferior (cells situated medial
against the Lemn. lat) deseribed by Kounsramm in the rabbit, partially agree with
my ne. sup. ventro-lateralis. (Journal f. Psychelogie u. Neurologie 1910).
( 1065 )
wot find here a splitting of the nucleus reticularis superior into a
dorsal and ventro-lateral group respectively (4 and 6, resp.). The
cells are here spread more equally through the formatio reticularis,
principally more dorsal in the bulb. Whether of the cells tying
between the bundles of the lateral lemniscus some must be considered
as very ventrally situated reticular cells, belonging to the said ne.
reticularis, [ do not venture to decide. | do not consider it probable,
however.
Owing to the extreme diffuseness in the arrangement of the reticular
elements of the various vertebrates and the frequent difficulties in
defining these from non-reticular elements, if is not sasy to state the
result of my labours in a few words. Nevertheless | believe I may
place in the foreground the following facts.
1. As far as | know, in the lateral field of the oblongata, a more
or less pronounced massing of the large reticular cells occurs m all
vertebrates except in cyclostomes and amphibians.
2. In all animals, moreover, large cells occur in the raphe in the
caudal part of the oblongata; in the frontal part of the oblongata
the large cells are wanting in the raphe, with the exception ot
chelone, where they also occur on the level of the trigeminus-nucleus
as an independent group, distinet from the vagus group.
3. In the reptiles, birds and mammals a raphe-nucleus consisting
of small cells is constantly found in the anterior part of the oblongata
about the posterior boundary of the corpora quadrigemina posteriora.,
4. The frontal group of the lateral reticular cells undergoes in
the phylogenesis a strong increase, and a division in such a way
that « portion of these cells retains their dorsal position, while
another portion (the number varies in the different animals) acquires
a more ventro-lateral position on the lateral leminiscus, or directly
medially to it.
5. Phocaena exhibits a deviation from the general mammalian
type by a lesser differentiation of the reticular nuclei in’ the anterior
part of the oblongata.
( 1066.)
Microbiology. — « Pigments as products of oridation by bacterial
action.” By Prot. M. W. Brierinck,
(Communicated in the meeting of February 25, 1910).
The following experiments make it possible easily to find some
notable bacteria more or less cotmmon in our surroundings and partly
not observed hitherto,
1. Formation of Protocatechetic acid from Chinie acid.
As Loéw') had shown that I proc. solutions of calcium chinate
become brown when exposed to the air by the formation of proto-
catechetie acid, EmMmrninc and ApgperiaLprn’) have investigated this
biochemism bacteriologically. They neutralised 10 proc. solutions
of chinie acid with calcium carbonate, added 0.5 proc. peptone,
0.1 proc. kalium phosphate, and 0.1 proc. magnesium phosphate,
inoculated this mixture with a few drops of an infusion of putre-
fying meat, and cultivated for some weeks at 35°C. They obtained
protocatechetic acid together with a slimy bacterial mass in the
liquid, from which it was possible to isolate a likewise slimy
Micrococcus, which proved to be the cause of the production of the
latter acid and was named JZ. chinicus.
The reaction goes after the formula:
C, H,;0, + 0 = GH,0, + 3/BYO
Chinic acid Protocatechetic acid
whereby at most 12 proc. chinic acid is converted; into what the
remaining 88 proc. change is not noted by these experimenters. It
is remarkable that only one atom of oxygen takes part in this
reaction.
As the said authors had not applied in’ their experiments the
so intense colouring of ferrisalis by protocatecheti¢ acid, it seemed
desirable to make use of it for the easier recognition of the inferred
bacteria,
To this end the experiment was effected as follows:
For the rough or preliminary cultivation a liquid was used of
the composition :
1) Berichte der Deutschen Chem. Gesellschaft, Bd. 14, pag. 450, 1902.
2) Ueber einen Chinasiiure in Protocatechusiiure tiberfiihrenden Pilz. Gentralblatt
tir Bakteriol. 2te Abt. Bd. 10, Pag. 337, 1903.
( 1067 )
MAO NWUC eee ee es os ss, cL OO-OU,
Dikaliumphosphate = J e50%. >. 0.05
Ammoniumebloudiies sess 2 0.05
Caleiumchinate (CH,,O0,), Ca + 10H,O 0.1 to 16
Reveelnltovidl 7) 2 isd Seg es ee 0.01
In a wide Eruexmuyer flask, so that a strong aération occurs in
the thin layer, inoculated with soil and cultivated at 20° to 25° or
30° to 385° C., the liquid colours deep black after a few days, in
consequence of the formation of ferriprotocatechate.
To purify the bacterial culture a trace is transferred to a similar
medium and eultivated at 20° or 30°C.
If this culture is sown on a medium of the same composition but
solidified with agar and containing some ferricitrate*), colonies are
obtained, from the cultures kept at 20° to 25° C., of different
varieties of B. fluorescens, and from those kept at 380° to 35°C.
chiefly of a Micrococcus, all lying amid diffusion fields of ferriproto-
catechate of an intense violet or red colour, This J/crococcus belongs
perhaps to the same species as that described by Hamertinc and
ABDERHALDEN, but then certainly to another variety, for it does not
produce slime, neither in’ presence of peptone nor of ammonium-
salt. This form, very common in our environment and which ean
be obtained with various other organic salts in a similar way as
with chinate, I shall name Micrococcus calco-aceticus, as caleium
acetate is very fit for its accumulation. Here it may be observed
that acetates are also very useful for the accumulation of certain
varieties of B. sluorescens non-liquefaciens which still grow at 380°C.
Streaks of these various bacteria on broth agar with one proc.
calcium chinate, and a little ferricitrate, or on the above medium,
give again deep black or red-coloured diffusion fields of ferriproto-
catechate.
Part of the chinate oxidises directly to water and calciumearbonate
which precipitates as crystals dyed deeply violet, by having sueked
up the ferrisalt of the protocatechetic acid during their crystallisation.
Other species, able to convert the chinie acid into water and
calciumearbonate or protocatechetic acid, but not found in the fore-
going experiments, are mentioned in the following table where it is
indicated by + and — whether the substances placed at the head
are either or not formed. These experiments were made with broth
agarplates with 1 proc. calciumehinate at 30°C., or use was made
1) Ferricitrate does not give a precipitate of ferriphosphate in the somewhat
alkaline broth.
( 1068 )
of the above named nutrient liquid containing ammonium chlorid,
alter its solidification with ager.
ES SS
3 Protoca- Calcium-
From chinates result by techetic carbonate as Remarks
acid crystals
Bacillus prodigiosus t
punctatus = =
Aérobacter coli _ —
Fs aérogenes + = Some varieties
- liquefaciens _ _
Pseudomonas aromatica = =
y jiuorescens non .
liquefaciens + + Some varieties
3 fluorescens
liquefaciens + + Some varieties
' pvocvaneus + +
Proteus vulgaris -- _
Microspira tyrosinatica — —
Micrococcus calco-aceticus + -F All varieties
Acetic acid bacteria —
Yeast species _
This table shows that the common species which oxidise chinate
to protoeatechetic acid, namely the flnorescents, also embrace
varieties devoid of this faculty.
The second column is but of relative value, for a number of bacteria
oxidise the chinate and grow from it with great intensity without
crystallisation of the thereby formed calciumearbonate. The chinates,
belong (with the malates) to the most easily assimilable organic salts
for non-sporulating bacteria in general.
It is remarkable that there do not seem to exist spore-forming bacteria
which produce protocatechetic acid, for I did not succeed in obtaining
microbes from pastenrised materials, such as garden soil or canal
mud, whieh, in solutions or on plates of the before given composi-
tion gave rise to an obvious change of colour. But by various
spore-formers calciumehinate was changed into carbonate, though
slowly.
( 1069 )
With exclusion of air solutions of chinate are apt to come into
fermentation, as was already observed by L6w, whereby carbonic
acid, acetic acid and propionic acid are formed. Hydrogen was not
found; the inferred microbes belong to Aéfrobacter aérogenes and
allied forms.
2. Oxidation of Quercite to Pyrogallic acid by
Pseudomonas aromatica.
The knowledge that chinic acid derived from the hexamethylene
ring (hexahydrotetraoxybenzoic acid) can so readily be converted by
many microbes into an aromatic substance, easily demonstrated by
the ferri-reaction, suggested the question if substances exist, related
to chinic acid, that behave similarly.
This consideration induced to subject quercite to an investigation
analogous to the foregoing, the structure of this substance being the
hexamethylene ring, in which 5 atoms of hydrogen have been replaced
by hydroxyl. It was proved that also here, under the influence of life,
an aromatic substance is easily produced, but at the same time that
addition of a ferrisalt to indicate that substance is superfluous ;
further, that but one single species of microbes seems to exist, of
which only some varieties possess the faculty to form that substance,
A more precise investigation showed that here the chemical reaction
proceeds quite correspondingly with the oxidation of chinic acid,
but that the product is, after all probability, pyrogallic acid, evidently
resulting thus:
CAH..O, -- 0 = C,H,0,-— 34,0
Quercite Pyrogallol
Here, too, only one atom of oxygen per molecule of quercite is
used. It should be noticed that in these experiments a large portion
of the quercite vanishes in another way, probably as carbonic acid
and water.
The microbes causing this conversion are very generally distributed
in our surroundings, but although there occur among them a number
of clearly distinct varieties, they all belong to one and the same
species, namely that of the “aroma bacteria”, well known in milk
and milk products and for the first time distinetly described by
Miauna‘) as Pseudomonas aromatica. It is a polarmonociliate short
rodlet, little motile in plate cultures, more so in broth,
1) System der Bakterien, Bd. 2, p. 880, 1900; with fig. Bd. 1, Tab. 1, fig. 8.
This description is based on Bacillus crassus avomaticus Tararorr. — Probable
synonyms: B. aromaticus lactis Grimmer, Centralbl. f. Bacteriol, 2te Abt., Bd. 8,
70
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1070.)
The very dark colour of the pigment in an aerated alkaline medium
makes it easy to detect the quercite bacterium. If for example, on
a broth agar plate with 0.5 proc. quercite, some drops of sewage
water are spread, there is much chance that after one or two days
al 380°C. some colonies appear that are jet-black, or lie amid a black
diffusion field, distributed among the numerous non-pigment producing
colonies, which latter are little troublesome, excepting /. /luorescens
liquefaciens, whose secretion is injurious to the quereite bacteria.
In a previous paper I alluded to a simple experiment whereby
aromatic milk results *).
To this end milk should be kept at a relatively low temperature,
for example at 15° to 20° C., with full admission of air, so that
it is left to spontaneous corruption by the aerobie germs it contains.
The acidification is at first feeble on account of the low tempera-
ture, but it is then that the “aroma bacteria” increase very much
and produce the characteristic ester which has not yet been nearer
examined.
If of such aromatic milk streaks are made on a quereite plate
of the above composition a large number of brown colonies of
quercite bacteria appear after 2>< 24 hours at 30° C. An examination
of their faculty of producing the aroma in milk proves that it does
exist but only in a slight degree. The real ‘aroma bacteria’, which
develop by the side of the “quereite colonies” and correspond with these
in all other respects, do not possess the power of producing pyrogallol
from quercite, hence, though belonging to the same species, they
represent other varieties. The quercite bacterium might thus be named
P. aromatica var. quercito-pyrogallica. That P. arematica is so easily
distinguished as a species, makes it in this case possible to indicate a
character by means of which forms found in nature and seemingly alike,
may be recognised as belonging to different varieties. The oxidation
function here, thus proves to be very variable, being present or
S$. 584, 1902. — B. butyri aromafaciens herra, Bacillus N°, 41 Conn ; Pseudomonas
fragariae Gruser, Centralbl. f. Bact. 2te Abt. Bd. 9, p. 705, 1902. — Ps. fragariae
Gruser, Id. Bd. 14, p. 122, 1905, — and Ps. fragaroidea Haran Huss. id. Bd. 19,
p. 661, 1907. — Perhaps likewise the yellow-coloured Ps. trifolii of Hanaup Huss,
ld, Bd. 19, p. 68 and 149, 1907, and several other different forms less easily
recognisable in the literature are synonyms. — Bacillus esterificans Maassrn, Arbeiten
des Kais. Gesundheitamtes, Bd. 15, 1899, is quite another species, producing spores
and belonging to the hay bacilli, and thus related with Granulobacter pulymyxca
PRAZMOWSKI.
') Fermentation lactique dans le lait. Archives Neérlandaises, Sér. Il. T. 13.
p. 350, 1907.
(1071 )
lacking in closely allied forms which are themselves constant and
differ only in this quality.
Another character by which the natural vavieties of 2. avomatica
ave mutually distinet, consists in their very unequal power of lique-
fying gelatin, this power being intense in some and quite absent in
other varieties, with all intermediate degrees. The same is to be
observed in the quercite bacteria; hence the variability of this property
is in some degree a property of the whole group.
All varieties, apparently without exception, produce in glucose
bouillon about 8 em.? N acid per LOO em.* liquid. For growth,
oxidation and acid formation, peptones are wanted as source of
nitrogen, ammonium salts and nitrates can hardly serve as such and
only in pure cultures, but by no means in free competition with
other microbes.
Although aromatic milk contains a great many quercite bacteria,
its flora chiefly consists of other varieties of P. aromatica, but the
following experiment, based on the principle: slow rising of the
concentration of a good nutrient medium apt to produce a slight
acidification, makes it possible almost exclusively to obtain the quercite
bacteria.
Large glass beakers are filled with 1 L. of distilled water and
therein are floated a few small dialysators of parchment paper,
manufactured by ScnLeicHErR and ScuotLn, of the shape of experiment
tubes, each filled with about 15 cm.* of extract of greenmalt.
This extract is prepared by rubbing two parts of greenmalt with
inree parts of water in a mortar and filtvating after some hours’,
digeration at room temperature. The clear solution contains relatively
little maltose and is of course extremely fit for bacterial growth,
where, likewise as in milk, lactic acid ferments are able to develop,
but only little lactic acid can be formed on account of the low rate
of sugar. Kept in a room where the temperature varied from 15°
to 20°C. the spontaneously corrupted infusions in the beakers produced
at repeated experiments, made in December 1910 and January 1911,
so great an excess of quercite bacteria, that other species could hardly
be found in the black mass, obtained by streak inoculations on broth-
agar quercite plates.
If instead of submitting the malt extract to dialysis, different
quantities of the extract itself were directly added to the water,
then, with for the rest like conditions, much less quereite bacteria
developed.
The aroma formed in the malt extract is of the same nature as
that found in aromatic milk.
70*
( 1072.)
Other bacteria but the above named, producing a pigment from
quereite, have not been found, neither by experiments with non-
sporulating forms at higher temperatures nor among the microbes
that remain alive in pasteurised materials.
Finally it may be remarked that quereite (which is not susceptible of
alcohol fermentation) is attacked, when no air is admitted, by fer-
mentation bacteria of the Aérobacter-group, such as A. aérogenes,
under production of carbonic acid, hydrogen, and of organic acids
which have not yet been more exactly examined.
3. Oxidation of Tyrosine to Melanine by Microspira tyrosinatica.
It is well known that the enzyme tyrosinase is able to oxidise
tyrosine to a jet-black substance, which is formed at the air from
dioxyphenyl acetic acid or homogeantisinie acid. It is aceepted that
this substance originates after the formula °).
Go HeNO, -- 0, — CH, 0) So ayene enue
Tyrosine Homogentisinic acid
In the experiments now to be treated | could not find ammonia
which, according to the formula should come free, probably because
all the nitrogen present in the tyrosine, is used for the growth
of the bacteria.
Hitherto this conversion had only been studied as a consequence
of the action of an enzyme occurring in higher plants and also in
higher Fungi. Nobody, however, had as yet deseribed tyresinase-
producing bacteria, whose existence will be referred to in the next
lines. As they ave rather easily cultivated and are able to produce
great quantities of the black pigment formed from tyrosine, which
is identic with or closely allied to the melanines of the human body,
they are of importance for experimental physiology.
Tyrosine microbes are small vibrios, chiefly occurring in the sea
and during the winter months present in the plankton. Fresh water
is not however quite devoid of them and without much trouble
they may be isolated from sewage water. The forms living in the
sea produce, at least as regards the stronger varieties, besides tyrosinase,
also tyrosine, and as this takes place from peptone they are to be
recognised by the black stains which their colonies produce on
broth-agar plates, which, as we have to deal here with inhabitants
of the sea, should contain 5 proc. Common salt. It is remarkable
1) AppeRuatpen, Physiolog. Chemie. 2te Aufl. p. 367, 1909.
( LOTS
that these tyrosine-vibrios of the sea can be accumulated in seawater
with addition of agar as sole source of carbon, ammonium chlorid
as nitrogen food, and kalium phosphate. In this respect they show
analogy to the gelase vibrios, which secrete the enzyme gelase by
which agar is changed into sugar and which are also easily pro-
duced in this manner.
Accumulation of these microbes in seawater with tyrosine as
source of carbon has not succeeded, as little as with their relatives
from fresh water, by corresponding experiments. Endeavours to
accumulate the latter from sewage water with tyrosine as source of
carbon and nitrogen have produced fluorescents, which thus prove the
stronger in the competition at such an “elective” cultivation.
The fresh-water form is fairly common in the sewage water of
Delft; to obtain it in pure culture the undilute sewage water
must be poured over a plate of the composition :
itpwiatoner | ne Buc sod Peel
TV ROSINC: ) cp hc, Se cymes: boa Oe O.1
Natrium carbonate . . . , 0.1
Dikalium phoshate . . .. 0.05
UWE OM een At A eae eA at 2
The superfluous water is allowed to flow off the plate, which is
cultivated for some days at 30° C.
It is true that here the tyrosine is at the same time source of
carbon and of nitrogen, but the method is now a “separative” one,
as competition is excluded.
On the second or third day peculiar black spots are seen to appear
around some colonies and slowly extend over a distance of some
millimeters‘). The black pigment proves able to diffuse only to a
rather short distance, whilst the enzyme itself remains bound up with
the bacterial bodies as belonging to the endo-enzymes. That here we
have indeed to deal with a true enzyme, is more easily shown in
the species of the sea than in the fresh-water microbes. To this end
some material cultivated on broth agar is killed by the vapour of
chloroform, then transported to a culture plate of the above com-
position, or to a nutrient liquid of the same preparation, but with
omission of the agar. At a temperature of 40°C. the black-colouring
is then rather quickly perceived but, of course, without development
1) As the so generally distributed fluorescent bacteria likewise attack tyrosine
under production of a light red-brown pigment, there are always found spots of
that colour on such culture plates, which can, however, by no means be mistaken
for those of tyrosinase.
( 1074 )
of the germs. As endo-enzymes may be considered as constituents
of the proteplasm, it is net surprising that the reactions with such
preparations, containing only dead material, are feeble, for the enzyme
itself is for the greater part annihilated. Hence, in my opinion,
endo-enzymes are best studied when still within the living cells
themselves and by considering them as an essential part of the
living protoplasm. Taken in this sense tyrosinase may be called a
“respiration enzyme’, and it is remarkable that as a product of
respiration, beside the carbonic acid, ammonia is formed, instead
of water as in the ordinary respiration.
In sewage water only a small number of tyrosine bacteria are
found per cM*. This number may be a little increased by leaving
the sewage water for some time at room temperature, then making
on plates streaks of the microbes accumulated in the layer at
the surface. This microbe layer, very rich in infusoria and flagel-
lates, produces, in particular as it seems in late summer, many
more tyrosine bacteria than the sewage water itself. Nevertheless,
as said above, it has not been possible to find a really good
accumulation method of these tyrosine bacteria, although many trials
have been made.
The black pigment can be prepared in great quantities by cultivating
the pure microbes at 30° C. in large Ernenmnyer flasks of the said
feebly alkaline solution of natriumtyrosinate with the required anorganie
salts. The conversion is relatively slow, so that it is complete only
after some weeks, but then a liquid is obtained which may be used
as ink. Traces of ferrisalts favour somewhat the formation of
melanine.
The tyrosine bacteria belong to the genus JMicrospira created by
Mictta. They are very small polar-monociliate, curved rodlets, some-
what varying in thickness, mostly thinner than the cholera vibrios,
which for the rest they resemble very much. Like these they quickly
liquefy broth gelatin and form on broth agar white, vigorously
erowing soft masses. Sometimes they are vnited in long chains; the
longest individuals show distinct curves and remind of spirilli. If
tyrosine is present in the nutrient medium, many individuals take
partly a black colour, swelling up very much and sometimes
becoming quite spherical, but the cilia do not become visible. They
produce indol, but do not give the nitvosoindol reaction. They grow
well in peptone solutions.
The fresh-water form colours broth agar without tyrosine not
or only very late, but if tyrosine is added the brothagar grows
rapidly black. The black-colouring begins still earlier on the before
(1075 )
mentioned culture medium, containing only tyrosine, although the
erowth on it is much slower than on brothagar.
As nobody had ever before observed tyrosinase formation by bacteria,
there is reason to consider these microbes as new for science; the
species occurring in sewage water may be called Microspira
tyrosinatica’). It is an organism highly sensible to the nature of the
nutrient substances, apt to lose the tyrosinase function by various
not yet explained influences, but notwithstanding continuing for years
in the laboratory as an hereditary constant species.
§ 4. The brown pigment formed by the acetic bacteriun
Acetobacter melanogenum.
When beer is left to corrupt at the air a film forms at the
surface in which Saccharomyces Mycoderma and acetic bacteria
develop, or only the latter, in accordance with the temperature and
other culture conditions. If the corruption takes place at room tem-
perature it will be perceived, when the beer is contained in beaker-
glasses, that after the film has closed over the surface, some of the
beakers slowly assume a dark brown colow and after two or three
weeks get so dark, that the beer seems coloured by caramel.
For the isolation of the here active organisins streaks are to be
made of the film on wort- or beer gelatin. Then these culture
plates being kept tivo or three weeks at room temperature, they show
deep brown spots evidently coloured by the same substance which
originated in the beer itself, spots in whose centre the colony of a
vinegar bacterium is lying. As a matter of course the plates are
further covered with colonies of Saccharomyces Mycoderma and of
ordinary vinegar bacteria.
Culture plates of 100 water, 10 gelatin, 2 peptone, 3 glucose,
are also very good for growth and pigment production. The “brown”
vinegar bacterium obtained in this way, I recently described under
the name of Acetobacter melanogenum*). It is commonly but not
always, a motionless organism, which can only develop on peptone
as source of nitrogen and produces the pigment from this substance,
if at the same time glucose or maltose is present. Other nitrogen
sources but peptone bave not been found. The sugar is during the
1) Micuta’s Microspira nigricans, System d. Bakterién, Bd. Il, p. 1013, does not
liquefy gelatin, but colours it brownish black. Whether tyrosine and tyrosinase
occur in this case has not been examined.
2) Piementbildung bei Essigbakterien. Centralblatt f. Bakteriol. 2te Abt. Bd. 29,
S, 169, 1911.
( 1076 )
growth partly converted into a strong acid, probably gluconic acid.
In presence of alcohol much acetic acid is formed. Consequently
beer acidifies with great intensity.
Solutions of LO proc. glucose and 2 proce. peptone in tapwater
with 10 proc. calcium carbonate at 25° or 380°C. grow black after
a few weeks, the carbonate changing at the same time into calciun-
oluconate.
Although for the formation of the pigment the simultaneous
presence of sugar and peptone is required, there is cause to admit
that the pigment is an aromatic substance, taking rise from peptone
alone, whereas this reaction only occurs during the growth of the
microbe, for which growth also sugar is wanted. In an earlier paper
I gave to such processes the name of auxobolisms.
By the formation of the pigment in the gelatin plates the gelatin
not only becomes deep brown, but at the same time quite insoluble
in boiling water, which is the more remarkable as the newly
isolated stocks of A. melanogenum liquefy the gelatin in the be-
ginning (probably by the intense acid production and not by a
specific enzyme). Older stocks lose this liquefying power, probably as
they become slower in producing acid; their pigment formation,
however, remains the same.
Only very few substances render gelatin insoluble in boiling water
as for example, formalin and chinon, whilst among the microbes,
as far as known, only Actinomyces chromogenes (Streptothrix chro-
mogena) has the same effect on gelatin by chinon production from
peptone. As, moreover, the brown-coloured gelatin reduces silver
in an ammoniacal solution of silver nitrate, and produces metallic
mercury from an alkaline mercury solution, there is reason to admit
that A. melanogenum does really produce chinon, this substance
giving the same reactions. However the most characteristic reactions
of chinon could not be obtained, namely, the blue-colouring of guajac
emulsion and the production of iodium from hydroiodic acid. But
the secretion product of the brown vinegar bacteria gives quite well
the black-colouring with ferrisalts, also characteristic for chinon.
SUMINALY.
The oxidation of chinie acid to protoeatechetic acid is brought
about by number of microbes beionging to very different groups and
is easily demonstrated with ferrisalts. In particular J/rerococens
calco-aceticus and some varieties of B. fluorescens non liquefaciens
possess this faculty in a high degree and hence can be found and
isolated from mixtures of bacteria.
( 1077 )
The oxidation of quercite to pyrogallol is caused only by certain
varieties of Pseudomonas aromatica, so that we have here a very
specialised function. Green-malt extract altowed to grow “aromatic
by spontaneous corruption at low temperature abounds in that species
and always contains numerous quercite bacteria which besides, are fairly
common in sewage and even in canal water as also in “aromatic milk”.
Melanine formation from tyrosine is proper to certain sea-vibrios
and to Microspira tyrosinatica not uncommon in sewage water and
easily found by this reaction. It is a microbe closely allied to the
cholera and the photogenic vibrios. The tyrosinase function is some-
times suddenly lost by unknown influences. but may return in the
same steck. Notwithstanding, the species can be considered as fairly
constant and remains so for years in the laboratory.
Beer, poor in extract, colours dark brown when corrupting at the
air. This is owing to the presence of a vinegar bacterium, ceto-
hacter melanogenum, which produces a pigment reminding of caramel
from peptone. By the secretion products of A. melanogenum gelatin
is as it were tanned and becomes insoluble in boiling water. Perhaps
chinon is inferred in this process.
In natural varieties of the species of microbes, which in all other
respects show no difference, the oxidation function in regard to certain
substances may be either or not present, but if present it may be
very constant in these varieties.
Zoology. “Whe HKutherian and the Metatherian carly blastocyst’.
By Prof. A. A. W. Huprecur.
The careful description of the early development of the Marsupialia
Dy Brot. J. P. Him im vol. 56; pt., of the Q: J: of micrs Sc. has
been anxiously awaited by numerous vertebrate embryologists, who,
being acquainted with Hinn’s important contributions (together with
Witsoy) to the ontogeny of Monotremes, expected that a firm basis
would henceforth be established on which the mutual relationships
of the more primitive and the more specialised Mammalia might be
built up. In this respeet however ihe valuable publication, above
referred to, is a deception. Far from being exhaustive it presents
the limited number of observations available in the light of an inter-
pretation in which the distinction of what is normal from what is
abnormal, is largely dependent on numerical relations and in which
the representatives of the so-called abnormal blastocysts ave not fully
introduced to the reader, nov sufficiently described at length, to enable
the interested student to form an opinion for himself.
( 1078 )
And yet this would have been doubly desirable because of the
fact that Prof. Hint, who, in his earlier paper on the placentation
of Perameles, has so markedly drawn together the Kutheria and the
Metatheria, finds in the development of Dasyurus grounds for again
separating the two subclasses more definitely.
Immediately after having become acquainted with Hinn’s first
mentioned paper | felt it my duty to attempt to convince myself
personally that the differences, just alluded to, do exist and 1 found
in’ Prof. Hin1’s laboratory the most hospitable reception and at his
hands the most liberal treatment, which permitted me to see and
weigh everything for myself, and even to draw and to model such
preparations as might seem to favour interpretations different from
his own. I cannot too highly value this disinterestedness, thanks to
which the problems involved will all the sooner be brought into a
light full enough for fellow-workers to draw their own conclusions.
And so I will here attempt to give a brief survey of the principal
differences which Hint has detected between the results obtained by
him for Dasyurus and my own generalisations. which were chiefly
based on personal acquaintance with the Eutherian ontogeny.
There is no doubt that the cleavage phenomena in Dasyurus, up
to the 16 cell-stage, are decidedly peculiar and that the arrangement
of the 16 cells in two rows of 8 cells each, fully deserves the
attention which Hint has directed to it. The first three cleavages
seem to occur constantly in a meridional sense. Only the fourth
cleavage takes place in a plane perpendicular to the three preceding
ones; the result being an aequatorial band of two cellular belts, one
composed of 8 smaller cells (representing what Hi. calls the formative
half of the blastocyst), one other of 8 somewhat bigger cells (the
non formative half).
Hint, is no doubt justified in emphasizing the points of difference
between this stage and the Eutherian morula. They are the following :
a. The Dasyurus blastulastage is normally open above and below,
until (very soon after) both the upper and lower solution of conti-
nuity will have ceased to exist, thanks to continued proliferation (in
the direction of the opposite poles) of the cells constituting the two
belts just mentioned.
b. The unilaminar blastocyst does wof contain an embryonic knob,
which has been described by all authors writing on the Eutherian
blastoteeyst, as a group of cells applied at one spot against the
exterior trophoblast, and which is composed of the cells that will
Jurnish the embryonic (formative) ectoderin as well as the whole of
the embryonic entoderm.
( 1079 )
In Dasyurus, as Hint repeatedly says, what is by him called the
formative hemisphere (itself a derivative of the belt of 8 smaller
cells) of the hollow blastocyst, fulfils the part that was just indicated
for the Eutheria by italics, whereas the lower or non formative
hemisphere of the blastocyst constitutes the trophoblast of the
Metatheria, comparable to that of the Sauropsida and Prototheria
and a fortiord also of the Eutheria ‘).
My own interpretation of the Metatherian morula, given on p. 7
of my article in vol. 53 of the Q. Journ. and not based on any
personal observations, has taken its starting-point from SELENKA’s
figures of early Opossum blastocysts, about which Hint expresses
grave doubts and which he refuses to look upon as normal. So
here the two specialists who have explained to us the early develop-
mental phases of Marsupials are diametrically opposed, one (SELENKA)
describing and figuring the presence — inside of the unilaminar
blastocyst —- of a mothercell (Urentodermzelle) of the entoderm,
whereas the other (Hinn) is convinced that normally there is no
cellular enclosure inside this unilaminar blastocyst wall of Dasyurus
and thus no mothercell of any embryonic knob comparable to the
‘inner cell mass” of Eutheria im the Marsupials.
For myself [have based my comparative considerations on SELENKA’S
data, but have interpreted them differently, looking upon Srnunna’s
“Urentodermzelle” as the mothercell not of the entoderm only, but
of the whole inner cell mass (embryonic knob).
The fact that Prof. Hint does figure one case (I. ¢. Pl. 3 Fig. 37)
in which a Dasyurus blastocyst contained one big cell in its cavity
and that therefore this case — emphatically stated to be abnormal
by Hit, — does present a certain amount of comparability with
Secenka’s figures above alluded to, made me all the more anxious
1!) There is a misunderstanding on p. 107 of Hitn’s latest paper as to my nod
considering the extra-embryonal ectoderm of Sauropsida as trophoblast. This
misunderstanding may have arisen in consequence of Hirt having cited the
condensed text of my Boston address, while my original paper (Q. J. vol. 53
p. 20, 24, 25) would have left no doubts in his mind and would at the same lime
have convinced him that the wonderful phenomenon in Dasyurus so excellently
figured in his fig. 42—46, 48—50, has been welcomed by me as a beautiful
confirmation of my contention that in Sauropsida and Ornithodelphia we ought to
identify the so-called extra-embryonal ectoderm with the entire trophoblast of
Eutheria. Here again the Rauber-cells of the rabbit, of Sorex among others have led
Hint astray, as they have formerly done Boxnev, and the intercalation of embryonal
ectoderm into the trophoblastic outer layer has not been sutfliciently kept in view,
although | have particularly calied attention to its details in Tupaja, Tarsius, Sus,
Cervus and so many others,
( 1080 )
fo become personally acquainted with his carly blastoeysts of Dasy urus
among whieh, as he distinctly mentions, in addition to the one
figured in fig. 87 he has come across yet more “abnormals.” Three
of these “abnormals” are here figured and are seen to contain
proliferating cells. Their aspect in many respects resembling that of
Sunenka’s Pl. 17 fig. 11 and Pl. 18 fig. 2, on which my own inter-
pretation, differing slightly from that of Swnenxa was based.
From the figures here given, magnified about 150° times and
obtained from consecutive sections of one blastocyst each, anybody
may make plastic reconstructions in space. It can then not be denied
that some of these blastocysts do contain an inner cell mass which
in the case of tig. 1 to 5 was of the utmost regularity and composed
of 16 cells. In most cases this mass is adherent at one spot to the
trophoblast, as we notice it in Kutheria. It moreover strikes us that
in fie. 1—4 the 16 cells seem to be timbedded in a sort of matrix,
distinctly the same as is present in the preparation from which Hi
has taken his fig. 87 and which he has there termed cy/, whereas
in that case (of which I also give illustrations in fig. Ta—d) the one
cell enclosed inside the blastocyst and designated by Hint by the
letters abn (standing for abnormal) is yet single in contradistinction
to the 16 cell stage just now described and figured. This one cell
is not imbedded in, but in close contact with the mass cyl. I do
not wish for the present to give a further deseription or interpretation
of this matrix, which Hii designates as coagu/um and which is also
found in those blastocysts which he regards as normal and in which
there is vo cellproliferation inside the blastocyst-wall.
I cannot convince myself that the histological aspect of the enclosed
cells would justify anyone to stigmatize them as ‘‘abnormal”.
However, from the evidence at present available I am not going
to conclude that, contrary to Hinn’s conviction, the blastocyst here
figured are normal and that those which he regards as normal — and
which though lacking any internal cell mass are more numerous —
should be looked upon as abnormal. 1 am only pretending that a
decision on this head is for the present moment premature, and that
we must necessarily postpone its definite solution until the examination
of a much larger batch of blastocysts of either Dasyurus or Didelphys
has furnished us with a key to this riddle *).
1) T may here remark that an attempt may be made to explain away the diffi-
cullies against a direct comparison between the “normal” and the *abnormal”
blastocysts in assuming that in many cases of Dasyurus the embryonal knob cells
arrange themselves in a flat layer without ever being overgrown by the unilaminar
trophoblast wall (such as is also the case in all the reptiles and birds as far as
( 1081 )
The other specimens here figured are developmental phases in
Which the same separation between an outer trophoblast and an
inner cCell-mass is also visible. Three of them are instructive as
representing yet different stages from fig. 1—5.
In fig. 6a—g sections are figured in which an inner ceilmass is
apparently present. Close inspection shows that the cells whieh in
fig. 6b—e appear to constitute an embryonic knob, at the same time
form part of the outer surface of the biastocyst. Whether these very
sections furnish arguments on which to conciliate HiLn’s interpretations
with my own, must remain undecided for the present. Fig. 8 makes
us acquainted with a blastocyst in which some two or three cells
appear to be enclosed within an expanded trophoblast, but here again
we may not look upon the specimen as decisive.
Fig. 9a—d_ represent a stage just a little earlier than that of
fig. 1—5. The enclosed cells are imbedded in a similar matrix and
also number about sixteen.
The size of the enclosed cells is intermediate to that of fig. 7 and
1—}. The distinction between trophoblast and inner cellmass is
equally evident.
I finally mention, but do not figure, a somewhat later and considerably
larger blastocyst, in which the cells that seem to represent the
embryonic knob are histologically less perfect than those in fig. 1—4
and might raise doubts whether this particular specimen is or is not
a link in a normal developmental series.
The facts which I have called attention to and which place us in
the position of having to suspend our judgment with respect to
fundamental support of Hin1’s theoretical speculations, prevent us
a fortiort from weighing the respective merits of Hin1’s theoretical
conclusions as compared to my own, and from entering into a debate
such as he has opened in the article cited. It should not be lost
sight of that just because the questions there raised are fundamental
the discussions ought to be preeminently thorough and unprejudiced.
The opposition with which my speculations on the first origin of
the allantois have been met in different quarters is largely caused
by that necessary sequel they lead to, viz. that no plausible phylo-
genetic explanation of the ventral stalk of the Primates and of the
free allantois of other mammals and of the Sauropsids is possible
as long as we hold on to the line of descent which is so emphati-
we know them), whereas in other cases these same cells undergo a certain amount
of development within this wall and only later become intercalated amone the
trophoblast cells in the way they do so variedly in numerous Kutheria.
( 1082 )
cally insisted upon by Hin and others: the derivation of viviparous
mammals from oviparous ancestors, whieh were provided with an
egeshell and iad a free allantois.
The Prototheria (Ornithodelphia), to the embryology of whieh Hint
has so largely contributed, are thus entirely out of the direct line
of descent of all the other mammals. Tt is only natural that Hina,
should be a bit prejudiced on this particular point. He admits in his
above-cited paper (p. LOO last paragraph) that the unilaminar blas-
foderm of the Prototheria is unmistakeably the trophoblast, but denies
that the cells situated internally to that in the region of the white
yolk bed are the mother-cells of the embryonic knob. | feel inclined
to believe that the footnote on p. 1079 and the misunderstanding there
explained away, will make him reconsider this denial and agree
with me that also here we ought to suspend our judgment till more
material is available.
I must finally point out that if my contentions on these last few
pages concerning the phylogeny of the allantois may to some appear
to be too provisional or unreserved I have just in hands and partly
already in the press a description of the very early stages of Galeopi-
theeus. In this mammal — the full description of which I hope will
be published before the autumn — we find a representative of an
order which is undeniably primitive, in the possession of develop-
mental features that force us to conclude that in the very early
stages it possesses a connective stalk (Haft- or Bauchstiel) between
embryonal shield and trophoblast, Whereas later on this stalk disap-
pears in consequence of the development of the coelom and is
gradually replaced in about the same situation by a free allantois,
the origin of which may be traced to processes in the very matrix
of the original connective stalk. This would be a direct argument
from ontogeny favourable to my speculations and not explainable in
any other way. I cannot however here do more than hint at it.
This paper might perhaps yet have harboured some amount of
refutation of certain objections to my theoretical views that were
advanced by Mac Bripr in a paper on Amiphioxus in No. 215 of
the Q. J. (vol. 54). 1 refrain from doing so because in that case
there are no positive facts upon which to base a rejoinder, as in
the case of Prof. Hini’s attack. Moreover, since it is patent that
Mac Brine (1. ¢. p. 382) has failed to understand my own views
about the phylogeny of the allantois to such an extent that he can
present it as follows: “along the stalk of connection between embryo
( 1083 )
“and vesicle the bladder subsequently grew and so the allantois
“was formed” any fruitful discussion on my phylogenetical specula-
tions is excluded from the starting point. And | prefer to abide by
Mac Bripr’s final jugdment, that: “Prof. Husrecur has read the book
“of Vertebrate development upside down” until an accumulation of
facts on either side will have brought the balance into a position
that will allow us to determine what is wp and what is down.
Heke Rl AUN AST ONE OLE MG URE S24)
“ig. 1—5. Dasyurus N°. 7.
la—lc. Three sections through blastocyst and shell. In @ and b only
trophoblastcells; in ¢ the inner cell mass (embryonal knob?) enclosed in
matrix (coagulum ?).
Fie. 2and3. The two sections through the inner cell-mass immediately following
that of fig. Le.
Fig. 4a—/. Eleven consecutive sections through the above, numbered so as to
enable us to reconstruct the mulberry shape.
Fig. 5. The actual reconstruction of the 16 cells composing the inner cellmass.
Fig. 64—6g. Dasyurus N®. 11.
Six sections, of which )—f are actually conseculive, showing accumu-
lation of massive cells in one blind corner of the blastocyst. it is closed at
the other end in 26 consecutive sections situated before Ga; it is thus
unilaminar. In 6) the eggshell is indicated.
Fig. 7a—d. Dasyurus N°. 12.
Sections through the same blastocyst and inner cell that have served
for Prof Hitu’s fig. 387. The nucleus (2?) of what Hitt calls the coagulum
has a very different character from that of the cell. 7a has its place in the
series between 7) and 7c.
Fig. 8. Dasyurus N°. 9.
A section showing shell, trophoblast and two apparently independent
cells inside the blastocyst.
Fig. 9a—d. Daysurus N°. 8.
Four sections through a blastocyst that has many pomts in common with
that of fig. 1
diate between that of fig. 7a and fig. 1¢; the number is also about 16;
the matrix (coagulum) is less regular. The number of trophoblast cells is
62, they are less numerous than in fig. le where we count 192.
Fig. 10 and 11. Copies of two figures taken from SetenKka’s development of the
Opossum (Wiesbaden Kreidel 1887) showing (fig. 19) Sevenka’s *Uren-
todermzelle” and (in fig. 11) the contrast between tropoblast and inner cell
mass, the latter on the point cf coming to the surface.
5. The size of the cells of the inner cell-mass 1s interme-
1) The number by which the Dasyurus are referred to in this paper refer to
preparations which in Httt’s collection are labelled as follows :
Dasyurus 7: 28. 16. VII. Ol. ** 39
E S2J/By 1162 Vit Ol 39
% 9: 46. Picro, abn. 29. 6. 04
= 10: 45. Herm. abn. 29. 6. G4
. 11: 45; Herm: * 29. 6,-04
, 12: 2B. 16. VIL. OL, 397.
( 1084 )
Mathematics. “Quadratic complexes of revolution and congruences
vf revolution”. By Dr. J. Wore at Middelburg. (Communicated
by Prof. Jan pe Vrins).
§ 1. The following treatise joins the investigation of Prof. Jax pe Vriis
Proceedings Royal Acad. of Amsterdam Vol. EX 1906/7, p. 216—221).
If we choose the Common centre ( of the two quadratic surfaces
of revolution O,? and O°, forming together the singular surface of
a quadratic complex of revolution 2, as origin of a rectangular system
of coordinates, then the roots of 42° — 2 kz+ A=O0 must differ
only in. signs, the bisingular points b, and b, where O,? and O,*
touch each other corresponding to those roots. Then we have /*=0,
so that the equation of 2 becomes
A (p,? + ps’) + Bp,’ + 2 Crp, Dp, + E(p,* + p,) =.» )
This equation can be written in each of the forms
E (». + p, ae 4. E @ | Vas) +.
-+ Bo, + 2(C + VAE)p,p, + Dp, =, . - (2)
A\?* A?
E (er, Vow = B(p,— Ps va f
+ Bp, + 2(C —YVAE)p,p, + Dp,i=0 . . (2%)
As the first members of (2) and (2*) can be reduced to four
squares, thus also to 2 products, out of each of the equations (2) and (2*)
two systems of congruences (1,1) can be deduced, out of which 2
is built up; we call them I and I”, resp. ©* and I’*. Each has
a regulus in common with each I”; likewise each T* with each
I’*. The directrices of all those congruences form 0,? and (,?,
§ 2. We apply to the vOy-plane a screwing around Oz of which
the angular velocity counted positively from Ox to Oy is in a ratio
to the translation velocity as 1:%. We choose the right lines p, and p,
along which coincide the velocities ef two arbitrary points ?, ‘and P,
lving in wOy as directrices of a congruence (1,1) in order to find
the equation of the complex which originates when I revolves
about Oz.
Let OP, be equal toa,, OP, =a,, 7 #0OP,=9, 7 cOP, =? + a.
The coordinates of p, are in order of succession of the indices:
a, sin 2, — a, cos , — k, ka, sin 9, = ka, cos D, a,” ;
those of p, are deduced from these by substituting a, for a, and
( 1085 )
d+ta. tor ?. A ray of the complex to be found is represented by
the equations
i
(p,+ kp,) sin D — ( Pst kp) cos D = . Ps—G Ps
1
and
, hk
(pet+kp,) sin (OF) — (pebhp,) eos 04) =" re = ae
Elimination of ® furnishes as equation of the complex :
(p,t kp.) sin? a + (p, +hp,)? su? a =
@ = k ke k = be
= Pe—& Ps |) — 2 Py—, Ps Pg Ms Pq )COS @+ Panam s Ps | (8)
a, \ a, a, a,
Equation (3) represents the complex 2 when the following five
relations nave been satisfied :
suv Ot =e oi po Io eo a0 (G)
A
k = se Be eo ae (OS
E
a,” — 2a, a, cosa + a,? SS AB ee ee (0)
hk?
——(a,*— 2a,a,csa+a,*)=—aDdD ..... . (@)
Cp aCins j .
\ a, ly ) * $ d
&y—- 2+ 7 cos a = 4A (Caste (ALE) Sect (3)
| Ty ay |
Hquation (5) furnishes two values for / differing only in sign;
the absolute value is ¥ —OB,? = —OB,?. From (6) and (7) ensues:
AB ;
at, a, — DE ; (9)
out of (8) in connection with (4), (5), and (6):
a,a, (C—kE)
(1 a ) ES Bee oc (OD
OS at LB (19)
For eaeh 2 we find one value of cosa. As however all conditions
remain satisfied when @ changes signs, we may add to P, instead
of P, also the image P,’ of P, with respect to OP,. Out of (4)
follows for every & one 4; finally we find a, and a, out of (6)
and (7); they are the radii of the circles according to which «Oy
is cut by O,? and Q,*. By division of (4) and (7) is evident, that
the distance from O to P, P, (or P,P,’) must be the same for both
values of /. This was to be foreseen; P,P, must touch, being a complex
ray, the complex conic of «Oy, being a circle with O as centre.
Its radius is:
~I
Proceedings Royal Acad. Amsterdam.-Vol. XIII.
( 1086 )
=A’
— fae eMrfrcss. oo, las SA(lhl
7 leas D (11)
§ 3. To fix our thoughts we suppose that A and # have the
same signs.
Bor 1/8 to each ray p, of the regulus R, wound to’
the right lying on O,* two rays p, and p’, are conjugated of the regulus
R, wound to the-right lying on O,’, so that 7 P,OP, = 7 P,OP, =a.
The complex 2 is originated by revolution about Oz of the con-
eruence I” with the directrices p, and p, as well as of I with
directrices p, and p’,.
For k= — ze to each ray p,* of the regulus 2,* wound to
the left lying on O,* are conjugated two rays p,* and p’,* of the
regulus /,* wound to the left lying on 9,*, so that the points of
intersection of p,* and p,* with Oy as well as those of p,* and
p'.* are seen from O under an angle «*. The complex 2 originates
by revolution of the congruence P* with directrices p,* and p,* as
well as of I’ with directrices p,* and p',*.
Let the right line P,P, be cut by O,? still in Q,, by O,? in Q,.
Through Q, pass the rays g, and q,* of A, and R,*, through Q,
pass the rays g, and qg,* of R, and #&,*. We then find that 2 is
built up in four ways out of systems of o' congruences (1,1), which
are originated in the following manner:
1. by revolution of I” with cine tes p, and p,, 2. by revolution
of I’ with directrices g, and qs 3. by revolution of * with g,*
and p,*, 4. by revolution of I* a p,* and q,*
If C=O, then from (10) follows that «&* =a and as p,* and p,*
are then the images of p, and p, with respect to «Oy, then $2 is
proof against reflection to wOy, thus symmetric.
§ 4. Let A, be a point of p,. The complex cone of A, consists
of the planes (A,,p,) and (A,,7’,), the singular ray s starting from
A, rests upon p, and p’,. If A, deseribes the right line p,, then s
describes the regulus e,, of which the system (p,, p,, p’,) is the
conjugate dne. As P,» Py and p', belong to reguli wound to the right
on O,? and QO,? and these surfaces touch each other in 6, and B,,
we find that p,, p, and p', are cut by two isotropic lines 5,/ and
LJ, at right angles to Oz so that / and / are the circlepoints of
vOy. If thus we bring through one ray s of @, the linear complex
C, having Oz as axis, then g, lies entirely inside C,, having s, B,1
( 1087 )
and 6,/ in common with it. When revolving about Oz we find that
o, remains in C, and so the section of C, with 2 forms a congruence
of revolution (2,2). If A, deseribes a right line p,*, then s describes
a regulus e@,*, which generates by revolution the same congruence
as Q,.
The singular rays starting from the points A, of O,* form a suchlike
congruence. The singular rays of 2 form therefore two congruences
of revolution (2, 2).
§ 5. A congruence of revolution C' (2, 2) is generated when @ is
cut by an arbitrary linear complex having Oz as axis:
jy a a= Vo 5 ol 6 to oo, (ile)
If we replace in (1) p, by —mp,, we' get:
A (pce pe) Bs} E (pe +p.) 0, . 2 8)
where B’ = B— 20m + DDS
We easily find for the focal surface:
AE («* + 9%)? + Bi (w? + y?)(A 4+ Ez?) + m? (A + Ee)? =0 (14)
So it consists of two quadratic surfaces of revolution /’,* and /,?.
which touch each other in the same points B, and Bb, as O,? and
O,*. Intersection of p,— imp, =O with the invariable complex (138)
furnishes a congruence with the same focal surfaces #’,? and F,°.
The common tangents of /’,° and /,’ form therefore two quadratic
congruences of revolution, which are each other’s images with respect
to rOy.
§ 6. Let a ray s of the congruence cut the planes 8, and @,, which
d 5 1 2
é : 5 aA
are in 6, and #, perpendicular to Oz, in P, (enue =e)
j : rf
( —A . : : q
and P, (to + alk If we express the coordinates of s in
’, Jy, v, and y, and if we then substitute them into (12) and (18),
1
— A EC
BEEN es ee HR 2m = 3. GY d= 6 ay -o (UB)
A? }
(HONS? Uh —= =» os 8 oc ao o (WG)
we arrive at:
and
The rays s of the congruence therefore determine a correspondence
(1,1) between the points of the planes 8, and #,. If P, describes
aray of the pencil (4,,(8,) then P, describes a ray of the pencil
(ake
( 1088 )
(2,,38,) and s describes a regulus S. To B, corresponds the point
at infinity of B,P,, to B, that of B,P,, so that in > are lying the
rays through £B,//B,P, and through 6,//5,P,. From this ensues
that touches 8, and p, in 4, and in 4, so that Oz is. an axis
of symmetry of + and O the centre.
So a congruence of revolution (2,2) is generated by the revolution
of a regulus about one of its axes of symmetry.
If only real congruences are taken into consideration, the two kinds
can be distinguished :
1. The regulus revolves around an axis of symmetry not cutting
it; then the focal surfaces are one-sheeted hyperboloids of revolution.
2. The regulus revolves around an axis of symmetry cutting it ;
then one of the focal surfaces is an ellipsoid of revolution, the other
a two-sheeted hyperboloid of revolution.
In the former case the contact of /? and F,° and the regulus
= takes place in imaginary points, in the latter case in real points.
In both cases the sections of «Oy with F? and F,? consist of
circles having as radii the axes of symmetry of S lying in «Oy.
One of them is imaginary in the second case.
Physics. — “Observations concerning anomalous dispersion of light
in gases.” (First communication). By Prof. W. H. Junius and
B. J. VAN DER PLAaTs.
Although it be now generally admitted, that anomalous dispersion
of light must influence .certain astrophysical phenomena in some
degree, yet the majority of astrophysicists opine, that such influence
cannot bear a general or radical character, but may in some special
cases only, near a few lines of the spectra of celestial bodies, per-
haps become apparent.
In order to make out whether that opinion is tenable, one has
to answer two questions. First: Is anomalous dispersion an excep-
tional or a general phenomenon, appearing in the vicinity of every
absorption line — provided that the conditions of the observation
are properly chosen? And secondly: Does the present state of physical
and astrophysical knowledge make it very probable or not, that in
the atmospheres of celestial bodies conditions prevail, from which
the appearance of quite conspicuous effects of anomalous dispersion
necessarily follows ?
In this paper we are not going to consider the second question ;
( 1089 )
it has been treated of on several occasions already '), and will also
in the future continue to form a subject of close investigation.
As to the first question, we notice that the dispersion theory has
settled it to a certain extent. According to that theory there is a
necessary correlation between selective absorption and the rapid
variation of the index of refraction for waves differing little in length
from the absorbed waves. The whole of experimental evidence sup-
porting the dispersion theory in general, may thus be considered
to plead in favour of the thesis, that really every absorption line
involves anomalous dispersion of neighbouring waves. The hypothesis
that many solar phenomena are perhaps produced by anomalous
dispersion, could therefore not be deemed unfounded or premature
even in 1900, when introduced by one of us*), although at that
time the peculiar course of the index of refraction near narrow
absorption lines, had really been observed with very few metallic
vapours only. Direct observations have considerably accumulated since
then. From researches by Lummer, Princsneim, Woop, Epert, ScHON,
Puccranti, Gerts~pr, Lapexpure, and others, we know that hundreds
of lines determine variations in the velocity with which neighbouring
kinds of light are propagated, exactly in the manner as required by
the dispersion theory.
The degree in which the phenomenon showed itself was very
different for different lines, and entirely dependent, of course, on
the conditions of the experiment. With innumerable lines it has
not yet been observed at all. But in view of the well-established
dispersion theory the supposition that certain absorption lines or
absorption bands give no anomalous dispersion *), is a more hazardous
one, than the supposition that the phenomenon will manifest itself as
soon as we shall have realized the proper conditions.
We propose to investigate those conditions for a number of gases
and vapours, and to inquire whether selective absorption really is
always accompanied by anomalous dispersion, as the theory demands,
or whether there are exceptions, which would make a correction of
the theory unavoidable.
The observations to be described briefly in this paper bear upon
iodine vapour, bromine vapour, and nitrogen peroxide. We used the
1) Proc. Roy. Acad. Amsterdam, XII, 266 and 466 (1909), XIII, 2 and 881
(1910/11). Les raies de Fraunhofer et ia dispersion anomale de Ja lumieére. Le
Radium VII, Oct. 1910.
2) Proc, Roy. Acad. Amsterdam, II, 575, (1900).
3) Cf. e.g. Hate and Apams, Astroph. Journ. 80, 230, 1909,
( 1090. )
method first applied to similar researches by Puccini’), then by
GuisLer*). As our present equipment bears a temporary character,
and we expect to dispose of better appliances at a later date, the
following short description of the apparatus used may suffice.
The light coming from an are lamp of 25 A. passes through a
Jamin interferential refractor, by which it is split up into two beams,
29 millimeters apart. On the path of one of the beams there was
a glass tube, 12 centimeters in length, into which a controlable quan-
lily of bromine vapour or of nitrogen peroxide could be introduced,
while the other beam traversed two pieces of plate glass, identical
with the ones shutting the tube. With both gases observations were
made at the temperature of the room, Lodine vapour, on the con-
trary, was examined at 55° C. For that purpose two equal glass
tubes, 40 ¢.m. long, were placed one in each beam, a Huranus electric
furnace enveloping them both, so that their middle parts, for a length
of 23 e.m., could be evenly heated to the same temperature. One
of the tubes contained some iodine. They both communicated with
the open air by narrow side-tubes.
By means of lenses the horizontal interference-fringes were focussed
on the slit of the spectrograph. As a low dispersion apparatus we
used a HiLGEr constant deviation spectrograph, with one dense flint
prism; a few observations were made with high dispersion apparatus,
consisting of a Row.anp plane grating (working surface 8 >< 5 ¢.m.,
5680 lines to the e¢.m.), two silverel glass mirrors of 150 and
250 e.m. focal distance respectively, and camera. |
The annexed plate shows threefold enlargements of some of the
spectrograms. Much detail is lost in the reproduction. When there
was no selectively absorbing substance present in one of the beams,
the interference fringes were perfectly smooth and almost horizontal,
apart from their fanlike spreading with increasing wavelength. As
soon as the absorbing gas is introduced, the velocity of certain waves
has inereased on the one path, of other waves diminished; so the
fringes suffer local displacements, quickly increasing as we approach
an absorption line, and thus show very intricate ineurvations. In
our arrangement a downward incurvation of the fringes means
increasing velocity of the corresponding waves in the vapour, and
therefore, decreasing index of refraction of the latter; an upiward
incurvation of course indicates the reverse.
') Puceranti, Mem. Spettr. Ital. 33, 133, 1904; Nuovo Cimento, Ser. V, Vol.
IX, 303 (1905).
*) H. Getster, Zur anomalen Dispersion des Lichtes in Metalldiimpfen, Diss.,
Leipzig, Barth, 1909.
( 1091 )
The first and second spectrum give the anomalous dispersion and
the absorption in zodine vapour. Proceeding in the direction of in-
creasing wave-lengths towards the sharp edge of any absorption band,
we see the fringes curve steeply down, which proves that the index
of refraction is quickly diminishing; within the absorption band the
index appears to increase, rather quickly at first, then slowly’), until
in approaching the next band it again falls off steeper and steeper.
This process repeats itself at every fluting, without exception.
The resolving power of the Hineer spectrograph was not sufficient
to permit of distinguishing the separate lines composing the flutings
of the iodine spectrum; but by analogy with quite conspicuous pheno-
mena observed in the case of nitrogen peroxide (as will soon appear),
it can hardly be doubted that also in the iodine spectrum each line
of a fluting causes the index of refraction to sink on its violet side,
to rise on its red side, and that the apparently continuous increase
of the index within each fluting results from the joint action of the
anomalies, due to the separate lines of that fluting. his inter-
pretation — which is in keeping with the dispersion theory —— is
strongly supported by the results of our observations on nitrogen
peroxide.
With bromine vapour we did not succeed in photographing equally
sharp and distinet anomalies of the dispersion as those obtained with
iodine. This may perhaps be due to the fact that, if one compares
such quantities of both vapours as will transmit nearly equal fractions
of the incident light, the intensity varies less within the bromine
flutings than within the iodine flutings. With equal average absorption
there are stronger contrasts in the spectrum of iodine, than in that
of bromine vapour. Nevertheless, on examining the third and fourth
spectrum, we may safely conclude that the anomalous dispersion in
bromine vapour bears entirely the same character as that in iodine
vapour.
The next three spectra relate to nitrogen peroxide; the
absorption spectrum (photographed while one of the interfering beams
was screened off) is placed between two spectra showing the anom-
alous dispersion; number 5 was obtained with gas of lower,
number 7 with gas of higher density. Exposure and development
were so timed, that on the one \photograph the region between 4 4400
and 2 5200, on the other that between 25200 and 26200 comes
out to advantage. Among the hundreds of lines visible in the NO,-
spectrum we could not find a single exception to the rule, that every
J
1) Cf. H. Getster, l.c., p. 24.
( 1092 )
absorption line produces a local shift’ of the interference fringes.
The amount of the shift depends, of course, on the quantity of gas
traversed. In speetrum 5 e.g. the dispersion anomalies are scarcely
pereeptible in the red; they increase in the main with decreasing
wave-length (as also the absorbing power of NO, increases in the
main toward the violet); in spectrum 7, the qnantity of gas being
greater, we observe very conspicuous anomalies already in the red,
and when proceeding toward smaller wave-lengths, see them so much
increase, that beyond 25000 anything like borizontal fringes has
disappeared.
At a few places, where more or less isolated lines occur, it is
clearly visible that the adjacent light shoots out into the next fringes
like sharp spikes, upward on the red side, downward on the violet
side of the line. Now, if we suppose the same phenomenon to
repeat itself near each of the many narrow lines which, crowded
together, constitute a band or fluting in the spectrum, we must
expect to find the dark fringes less dark, the bright fringes less
bright in any region corresponding to a band or fhiting. This par-
ticnlarity is indeed very conspicuous on the original photographs.
Where broad dark bands occur in the absorption spectrum, the
system of fringes shows somewhat vague, contrastless; whereas light
and dark distinctly alternate in the system, wherever the average
absorption is small.
Besides, we observe that in every region crowded with absorption
lines, the mean index of refraction rises with increasing wave-length,
and that in regions with few lines it sinks.
The strips 8 and 9 on the plate show parts of the NO,-spectrum
with high dispersion. Number 9 is an original-size reproduction’),
covering the part of the spectrum which, on 7, is enclosed between
a and d; of this a part again (lying between 6 and ¢) is givenona
three-fold scale in strip 8.
As in this case, for want of intensity, the time of exposure had
to be about one hour and a half, and because the arrangement had
no claim to perfect stability, the details are not so sharp on the photo-
graph as they showed visualiy. But on direct observation many
bands were now resolved into fine lines, and there could be no
doubt that each line clearly influenced the refractive index for
adjacent waves. Even the reproduction offers the required evidence.
Indeed, every absorption line of nitrogen peroxide visible on it has
1) The fringes are there curved in the opposite direction (as compared with the
other spectra on the plate), owing to a slight alteration in the arrangement of
the apparatus,
W. H. JULIUS and B. J. VAN DER PLAATS. ‘Observations concerning anomalous dispersion
of light in gases’.
540 550 560 570 580 590 600 610
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1093.)
a serpentine shape, owing to the fact that each bright interference
fringe, at its intersection with a dark line, seems to push it toward
the right at the lower edge, toward the left at the upper edge of
the fringe. This proves that the darkness of those lines is not execlu-
sively caused by absorption, but partly by anomalous dispersion.
The serpentine shape of the lines is not an optical illusion, for the
sodium line D, (D,, which lies at 2'/, m.m. distance to the right,
is invisible on the reproduction), originating in the are, is sharp and
perfectly straight. So we may take it for etablished by experiment,
that thousands of lines occurring in the spectra of iodine vapour,
bromine vapour, and nitrogen peroxide, produce anomalous dispersion
of the waves lying close to them.
The result of this investigation supports the thesis, that selective
absorption is always accompanied by anomalous dispersion.
Physics. — “Further experinents with lquid helium.’ By Prof.
H. KamernincH Onnes. Communication N°. 115 from the
Physical Laboratory at Leiden.
(Communicated in the meetings of Dec. 24, 1910 and February 25, 1911).
A. Tsotherms of monatomic gases etc. VU. Thermal
properties of helium.
§ 1. The helium-bath. Tn most of the experiments that one would
like to make at helium temperatures, it is necessary to transfer the
liquid helium from the apparatus in which it has been prepared to
another — the helium cryostat —— more suitable for holding the
apparatus arranged for these special experiments. In Comm. N°, 112
(June 1909) it was mentioned that this was goine to be tried; and
in the Jubilee book presented to J. M. van BemMenen it was further
stated that the transference had, in fact, been once successfully
accomplished. Although the success which attended this operation
allowed immersion in the protected helium bath of the apparatus,
with which it was shown that even at a vapour pressure as low as
0.15 mm. helium is. still a liquid, it was nevertheless evident that
this desirable result had been obtained only by accident. A method
that promises to be more efficient is now being developed, and I
hope to be able to make a communication in the near future
concerning if.
In the meantime, a few problems could already be studied with the
help of a liquefying apparatus resembling the original liquefying
apparatus (Comm. N°. 108, Proc. of May/June 1908) sufficiently well
( 1094 )
to ensure that when an experimental apparatus is introduced into its
its interior this experimental apparatus would also be surrounded
with liquid helium. To be certain that this was the ease, it was
necessary that the principle of the original liquefying apparatus should
not be altered in any way, and, hence, the difficulty that the liquid
helium would be contained in a spave that is practically closed above
by the regenerator spiral could not be avoided. But this space destined
to contain the liquid helium could still be made as large as was
found permissible from the experience gained with the liquefying
apparatus. An apparatus was, therefore, constructed to hold a ther-
mometer reservoir of greater dimensions than the one whieh had
been used up till 1909, a resistance thermometer such as was used
in the investigation of the electrical resistance at hydrogen tempe-
ratures, a dilatometer of -dimensions greater than those given in
Comm N°. 112, and also a control dilatometer.
The apparatus is shown in Fig. 1 Pl.1*). The letters are the same
as in Pl. III of Comm. N°. 108, and are accented where one of the
parts has been modified. Moreover, Pl. Il of that Communication
holds for the helium eycle as far as its use at ordinary pressure is
concerned. To allow the helium to evaporate under lower pressure
the tube that leads the gas off from the liquefier is coupled to the
wide exhaust of a BurckHarpr vacuum pump capable of transplacing
360 m.* per hour. To follow this operation the part D, and those
attached to it in Pl. I Comm. N°. 108 must be replaced by the
modifications shown in PI. IL fig. 1; connection with the pump is
made through /?,, a and this is closed by the tap 22; while 23 in
a bypass aliows a fine adjustment of the quantity of the gas that
is being removed; 24 and 25 allow the gasometer and the liquefier
to be independently evacuated (see Pl. Il Comm. N°. 108).
Besides the changes in the apparatus necessary to enable it to
contain the measuring apparatus, it remains to be remarked that a
second helium thermometer .Va,, Na,, Na,, now serves to indicate
the quantity of liquid hydrogen present in /’ instead of the two
thermocouples that were formerly used in conjunction with the small
helinm thermometer (now .V’,, .V,, .V,). The position of the liquid
surface in /’ can be ascertained much more easily from the motion
of the mercury in the capillaries NV, and .Va, than was possible with
the more round-about thermocouple measurements ; the liquid hydrogen
can therefore be used more sparingly, and the tedious preparatory
work of adjustment necessary for these experiments can be shortened.
') The alcohol glass with its attachments (cf. Pl. Il, Comm. N°, 108) Evis only
partially shown in the drawing.
( 1095 )
v
In the lower part —- the cryostat space — of the glass “/”, (Fig.
1 and Fig. 2) is the reservoir 7h’ of the helium thermometer, with
which the temperature of the bath is determined, the resistance &,
the dilatometer A, and the control apparatus of the dilatometer d.
And finally, a thick copper rod Cw is also placed in it so that,
since the liquid in the bath cannot be stirred, conduction along the
rod may keep the temperature of the bath more equable at all points.
The narrow space between the regenerator spiral A and the wall
of the vacuum glass /”, is filled with flannel, and now three capil-
laries pass through it instead of the single thermometer capillary
(that of Zh, Pl. IL Comm. N°. 108). One of these, 7h',, leads to
the thermometer (replacing 7,, 7h,, Th,, Th,, of Pl. 111, Comm.
N*. 108), the second to the dilatometer (this was already used in
Comm. N°. 112), and the third to the control apparatus of the dila-
tometer (connecting Jd with JI). Furthermore, instead of the two
insulated wires of the thermocouple (Comm. N°. 108) four insulated
wires Wa,, Wa,, W6,, Wb,, now pass through this space; these
are the pairs of wires that lead the current to and from the resi-
stance 2.
All these capillaries and insulated wires must pass through the
space that is filled with liquid air, which must still remain airtight
(this space is described under ( of Comm. N°. 108 § 2, and 6 Pl. II
of that Comm. shows how liquid air is iitroduced). This is accom-
plished by soldering the capillaries to the new-silver wall of the
liquid air vessel, while the insulated leads are enclosed in new-silver
tubes that pass through the wall and are soldered to it.
The operation of filling the lower portion /,, (Pl. I fig. 1) with
liquid helium is conducted in exactly the same way as is described
in § 4 Comm. N. 108. Practice in the various operations and the
improvement made by introducing the second helium thermometer
rendered it possible to save a fair amount of liquid hydrogen so
that, as a part of the necessary hydrogen had been liquefied the
previous day, it was possible to begin at half past seven in the
morning and have the cryostat part of the apparatus full of
liquid helium by a quarter to two in the afternoon. The circulation
pressure was kept at 25 atmospheres (cf. § 2, Comm. N°. 112).
The pressure under which the helium vaporizes is derived from
the pressure obtaining in the wide space beneath the german silver
chamber /°; from this space a tube passes through /’ and comes
outside the apparatus at p,; if is there coupled to the apparatus for
regulating and measuring the pressure. The difference of pressure
between this space and the surface of the liquid helium necessary
( 1096 )
to drive the vapour up between the coils of the regenerator spiral
was found, from measurements made with air, (o be less than '/,,
mm., and may, therefore, be left out of account. Only at very low
pressures will a correction be necessary for it in obtaining very
accurate results.
Nig. 2, Pl. Il shows the apparatus that serves to regulate the
quantity of gas pumped off through the exit valves; by such regu-
lation the temperature of the cryostat part of the apparatus is kept
as constant as possible, and from its constancy one can judge how
far the vapour pressure remains invariable; if also shows how this
pressure is measured. For pressures greater than 5 cm. the gauge /,
is used, for pressures between 5 em. and 1 em. /,, and for pressures
lower than’ dem. J;. By opening W;,,, JG;,,, 6); coreeina enna
Kis; Lon OV Ig, as the case may be, is brought to a definite pressure,
which is measured by /, or by the Mac Lop gauge /,; A;,, or Kj,
is then closed, and the taps regulating the rate at which the gas is
pumped off are operated so that the oil in the graduated sloping
tubes of the indicators remains at the same mark.
Any definite pressure and, therefore, any definite temperature at
the surface of the liquid in the cryostat can be quite satisfactorily
obtamed. The temperature of the bath, however, is less assured,
since stirring is not possible, and the conduetivity of Cu offers
but slight compensation for this defect. The lower parts of the
bath are at a higher temperature, and the corresponding vapour
pressure may be increased by 0.009 to 0.011 mm. of mereury
per mm. disiance from the surface of the liquid heliam; at the
lowest temperatures this is equivalent to a temperature difference
of 0.06 degree, and with this uncertainty we must be content as
long as we have not at our disposal a cryostat in whieh stirring is
possible; it is not, however, greater than uncertainties arising from
other causes that are already present.
§ 2. The Thermometer. Temperatures were measured by means
of a constant volume helium thermometer of zero pressure = 14.5
em. (Cf. Comm. N°. 112).
At the lowest measured temperature, the pressure of the gas in
the thermometer was 1.2 mm., and the vapour pressure of the
helium was only 2 mm. The cireumstances of measurement were,
therefore, pretty much the same with respeet to helium as if a con-
stant volume ether vapour thermometer were used for determining
ordinary atmospheric temperatures. In the present case there is,
moreover, the particularly small value of the pressure itself to be
( 1097 )
taken into account. Hence, in the very nature of the determinations
themselves there is cause for many uncertainties. In the meantime
however, it seems best to make a beginning by assuming that the
ordinary gas laws may still be applied at these densities, and to
postpone the application of corrections for the deviations that should
follow according to the law of corresponding states and for possible
condensation of vapour on the walis, etc., until experiments have
been completed which will afford an estimate of these corrections.
In this way one can at least attempt to obtain data cencerning cer-
tain thermal properties of helium. I mentioned in Comm. N°. 112
that at that time I had not been successful in overcoming the diffi-
culties that are always encountered when making measurements with
a thermometer, built on the principle of the one that has hitherto
been used, in the immediate neighbourhood of apparatus that are
used for the preparation of liquid helium. These difficulties have
not yet been wholly removed. The necessity for simplicity and ease
of manipulation of the apparatus, and the fact that the thermometric
measurements should be independent of all vibration and all disturbances
are difficult to reconcile. But still, it would appear that the tempe-
ratures obtained may be relied upon to within 1/10th of a degree.
The part of the helium thermometer that serves for the adjust-
ment of the constant volume, and for the reading of the pressure
is shown on the right hand side of Plate I. Its arrangement is simi-
lar to that of the hydrogen thermometer shown on Plate I of Comm.
N*. 95¢ (Oct. 1906) when this is being used for measuring hydro-
gen temperatures ; part of the lettering is chosen so as to correspond
with that of the latter plate. On account of the smallness of the
pressures to be measured at the helium temperatures the space above
the mercury in the adjustable double manometer tube / and fy is
evacuated, and, to make quite certain, they are connected to an
evacuated tube “ filled with charcoal and immersed in liquid air.
The manometer tube on which the pressures are read off, has, as
well as the adjusting tube, a small steel point, so that the difference
of level between the two mercury menisci may be obtained with
greater accuracy. The base éa which carries the point fo is slitted,
as can be seen in the figure. Before making any adjustments the
tap As, is closed, and it is opened to allow communication between
the mereury in the reading tube and that in the adjusting tube of
the manometer only after the mercury meniscus in the adjusting
tube has heen brought to the level of the point f, in the reading
tube by opening Ay, and moving the double manometer tube up and
down until this is accomplished. Then to proceed to an adjustment
( 1098 )
the adjusting tube can be shut off with Ay,. By a slight turn of the
screw s. and of the screw with which the fine adjustment of the
height of the manometer tube is obtained, both of which are within
the observer’s reach, the mercury surfaces are brought. as near as
possible to the two points; the height of the mid point between each
point and its mirror image is then ascertained with the cathetometer
provided with one of the reading microscopes of Comm. N°. 85
(April 1905) and of Comm. N°. 95/ (Sept. 1906) when the catheto-
meter was used as a vertical comparator.
In this way, taking account of the indication of the sensitive levels,
heights may be measured accurately to within 0.002 mm. To elimi-
nate the uncertainty in the correction for the refraction of light
through the glass at the place where the point is under observation
and that in the correction for the temperature of the equilibrating
mercury columns (as the capillary depression is only 0.01 mm. the
uncertainty in it may be neglected) the tap Ay, is introduced, and
the spherical vessel d, forms part of the dead space *). If Ay, is closed,
and the mereury that stood in the narrow stem d, while the
thermometer was being adjusted with As, closed, is allowed to sink,
there remains in the dead space only a very small and definitely
known fraction of the total pressure, and the adjusting tube of the
manometer must be lowered so as to bring the mereury levels once
more to the two points. The displacement is read on a finely divided
scale attached to the adjusting tube of the manometer, and at once
gives in mm. of mercury the thermometer pressure for the temperature
of the adjusting space, to which the only correction to be applied
is that for the pressure remaining over.
We need not siop to describe the different devices (cf. Comm.
N°. 60, Sept. 1900) by means of which the varions points to be
seen are so arranged that they can be brought in succession in sharp
focus into the field of the cathetometer; the significance of the air-
traps in the mercury filled connecting tubes is sufficiently obvious
from the figure, as is also that of the mercury filled rubber tube
Sw surrounding the rubber connecting tube S and its junetions with
the other tubes. On account of the comparatively large value of
viscosity, equilibrium is, in general, reached but very slowly between
spaces occupied by gas at such low pressures as those obtaining in
our thermometer reservoir and in the dead space. In the present
') A coupling is inserted in the capillary d; by means of which many opera-
lions and controls are much more easily accomplished; it allows the whole ma-
nometer part of the arrangement to be loosened, and either that or the remaining
appavatus may be connected independently with an air-pump, etc.
( 1099 )
instance, however, the favourable circumstance arises that only a very
small quantity of gas has to flow over, seeing that the dead space
is extremely small. Against the widening of the capillary it may be
urged that then the quantity of gas contained in it would lead to
inaccuracy owing to the uncertainty existing regarding the distribution
of temperature along it. After full consideration of the change of
viscosity and density with temperature, and also of constructional
difficulties, the low temperature portion of the capillary was made
of 37 cm. steel capillary of 0.5 mm. bore, and the part that is at
practicaliy room temperature was made of 50 em. copper capillary
of 1.0 mm. bore. The resulting uncertainty is, then, at the most,
Las
possible to adjust to O.O1 mm. within a period of 2 minutes.
while the viscosity is not yet excessive, seeing that it is
§ 3. Densimetric Apparatus. The part of the dilatometer that was
immersed in the helium bath consisted of a reservoir A, with a
stem A,, a narrow glass capillary A, continued by a steel capillary.
The mass of helium here present was determined volumetrically in
the bulb V, with a graduated stem both above and below, whose
temperature was determined by that of the surrounding water bath;
the pressure was read on a scale by using the branch Vo, of the
mercury reservoir J’,. The dimensions of 4, and V, are so chosen
that the position of the mercury for the desired pressure can be
read on the lower part of V,’s graduated stem before the dilatometer
has been filled, and on the upper part after the filling has taken
place. Moreover, the cross-section cf the graduated stem has been
chosen of such a size that when the dilatometer has been cooled
again with A’y, and Ay. closed, after filling it at the boiling point
to above the mark, the meniscus still remains in the stem even at
the greatest densities employed.
Although the capillary is very narrow at the part where its
temperature is uncertain, the correction for the gas condensed from
it when the dilatometer is cooled (keeping Ay, and Ag, closed),
which operates so as to cause a rise of the liquid meniscus in the
stem, is of great importance when the question arises as to whether
a maximum 7, onwards,
then the isotherms from the critical temperature to 7’, ave determined
from the equation of van per Waats, and from this equation, too,
are determined the maximum vapour pressure, and liquid and vapour
densities. Isotherms for lower temperatures are then determined from
these by taking the ordinates for each volume from the isotherm
for 7, and diminishing it in ratio of 7'to 7. The densities of coe-
( 1106)
visting liquid and vapour phases would thus remain unaltered, while
their common pressure would be simply proportional to 7. Although
with helium the maximum vapour pressure diminishes less rapidly
With the temperature than is the case with ordinary normal substan-
ces, the diminution is still very much greater in reality than would
he the case under the conditions above assumed.
A substanee that fulfilled these conditions would, moreover, exhibit
some other very unusual properties. The energy change at constant
temperature would be zero, the latent heat of vaporization would
alone be necessary for external work, and so the internal latent
heat of vaporization would be zero.
To realise the importance of the modilications which the ther-
modynamical properties of a substance undergo when the molecular
attraction decreases with the temperature, let us assume that it
decreases more rapidly than in simple ratio; in that case one is
brought to the deduction of still stranger properties. We may here
mention the case in which @—=c7" for temperatures below 7, < 77.
With such a substance at a temperature beneath 7’, lowering of the
temperature would diminish the difference between the liquid and
vapour densities, and this difference would disappear at a temperature
om : : a dp dp
7”, determined from the conditions = Oand — =0 by the equa-
av an
tion 7; T,.= 7°. Hence, an inferior critical point occurs from
4
which to the absolute zero the substance onee more behaves as a
perfect gas. For this case the change of energy with volume is
negative, and so too is, therefore, the internal latent heat.
We have still to examine if in other domains there ave assumptions
which are consistent with a decrease in the molecular attraction
as the absolute zero is approached.
The nearest comes in this respect KeLvry’s and J. J. THomson’s idea
of the structure of atoms. Assume, for example, that an atom consists
of a sphere of uniformly distributed positive electricity inside which
is an electron; then two such atoms wonld, at the absolute zero
where the electron comes to rest, exert no electrical attraction upon
each other. As soon, however, as the electrons begin to oscillate
about their positions of equilibrium, and begin to deseribe orbits
about their centres, attraction begins to be felt. An investigation
similar to those made by van pur Waats Jr. based upon the prin-
ciples of statistical mechanics would be necessary before one could
say how the molecular attraction of a system of such atoms would
depend upon the effeets of collisions and of temperature radiation
(they are, in fact, vibrators such as those assumed by P1LANcK and
Gators)
Kiysteiy). A priori, it seems to be not impossible that a inereases
over a definite temperature region as the temperature rises.
In the meantime all these theories do no more than emphasise
the fact that the behaviour of helium forces us to question the sig-
nificance of the absolute zero with respect to molecular attraction.
Hence it is of first consequence to obtain data concerning the ther-
mal properties here mentioned in connection with helium that
would lead to the solution of these problems, and also to investigate
related properties such as capillarity, viscosity, specific heat, refrac-
tive index and dielectric constant, for which data are still lacking.
For this purpose the solution of the problem of transferring liquid
helium to a vessel in which the regenerator spiral no longer inter-
feres with ihe introduction of measuring apparatus is absolutely
essential.
b. On the change in the resistance of pure metals at very
low temperatures, ete.
Ill. The resistance of platinum at helium temperatures.
§ 1. The resistance of a wire of very pure platinum at helium
temperatures. As soon as the possibility had been attained, it lay at
hand to extend to helium temperatures the investigation of the change
of electrical resistance of pure metals which, in Comm. N°. 99e (Sept.
1907), had been brought down to the lowest hydrogen temperatures.
For this purpose the resistance /’%%, which had been calibrated at
hydrogen temperatures as well as at others with the resistance
Pt; of Comm. N°. 99) (Sept. 1907) was available. It was constructed
on the model of Pt; (Comm. No. 99% § 2), and is indicated by 2
on Plate I of part A of the present paper, tig. 1. The thin platinum
wire is wound round a glass cylinder and is kept tight on it by
being wound while hot, and the thicker platinum ends JV, and WW)
are fused to the glass. To these ends the double platinum leads
Wa,, Wa, and W,,, Wy, are attached; they are not, however,
welded in the blowpipe, but are simply tin-soldered. The resistance
was measured on the Wearstone bridge according to the method
described in Comm. No. 99 and previous Communications. The ratios
of w,, the resistance at the temperature of the observation, to w
that at 0° C., are here given (p. 1108).
From this it appears that by descending to helium temperatures
0°
the resistance is still further diminished, but when these temperatures
are reached the resistance attains a constant value quite independent
of the individual temperature to which it has been brought. The
( 1108 )
Resistance of platinum wire Ptp
Tr Wi
Wo
273-09 K I
21,9 0.0171
14.2 0.0135
gps) 0.0119
Di 0.0179
ey 0.0119
results are plotted in fig. 8 Pl. TI, whieh shows well the asvmptotical
approach of the resistance fo a constant value at 4°.3 K.
§ 2. The probable resistance of pure platinun and of pure gold
at helium temperatures. In order to establish the exact significance
of the result just obtained we must take account of the fact that
the wire (tp was not made from quite pure metal, and we must
allow for the probable influence of this difference from pure platinum.
With this end in view, we shall first confine our attention to the
observations that have been made previously upon gold (Comm. N°. 99°),
Remembering the close resemblance between the differences of the
resistances of platinum and of gold wires from a linear function of the
temperature, we may, in view of the result that has been obtained with
platinum, extrapolate the Awy resistance curve to give a constant value
at helium temperatures. This has been done in fig. 3 of Plate III. The
parts of the curves obtained from observations are drawn with thicker
lines. We now note that, according to §1 of Comm. N*. 99¢ by
KaMertINGH Onnes and Chay (Sept. 1907) the influence of admixtures
can be represented with rough approximation even down to hydrogen
temperatures by an additive resistance that is independent of the
temperature. In this way the line correspondingly marked in the
figure was obtained for Aw;7; which was constructed of gold of a
smaller degree of purity (0.015"/, admixture against 0.005°/, for Avy).
According, now, to § 1 of Comm. N°. 99¢ the effect of admixture
should be pretty weil proportional to the quantity present, and this
would lead to negative values for pure gold. In the first place,
however, we do not know if the impurity was the same in the
two cases, nor do we know the influence of possible tensions in the
( 1109 )
metal; but moreover, such great uncertainty exists in our rough
approximations as to confine Our most probabie result in the mean-
time to this: That within the limits of experimental error (the degree
of purity attainable) the resistance of pure gold is already zero at
helium temperatures.
Let us return to platinum. The wire Pf, seems to be less pure
than Pt; (see table V of Comm. N°. 990), and, moreover, the fixing
of the wire on the glass may give rise to undesirable effects.
By putting the additive resistance once more constant, to a first
approximation, extrapolation gives for /%; the corresponding line
shown in the graph. But still, the resistance of Pt; may not without
further comment be regarded as the resistance of pure platinum.
A wire of greater diameter used by Honporn gave a greater relative
decrease of the resistance from 0° to —191°C. If we extrapolate
these values to lower temperatures the resistance remaining at helium
temperatures, and independent of any further change of temperature,
would be nearer zero. One may ask if it is not possible to put the
difference between the two wires obiained from Hrranus inversely
proportional to the thickness and in that way deduce a value for
pure platinum unaffected by the individual treatment of each; but
this method would lead us too far into the region of pure conjecture.
But still, the conclusion seems to be fully established that the resis-
tance of pure platinum is, within the limits of experimental error
— the attainabie degree of purity — already zero at helium temperatures.
§3. The change with temperature of the resistance of pure metals
at low temperatures. | was formerly of the opinion that the resistance
of pure metals reaches a minimum as the temperature is diminished,
and then, as the temperature sinks still further, again begins to
increase and becomes infinitely great at the absolute zero; but now
it seems to me to be more probable that, even before the absolute
zero is actually reached, the resistance if not zero, has become so
extremely small that it practically vanishes, and that this remains
the case for further lowering of the temperature.
In view of this result, then, we must also abandon the theory
that has served for years as a guide in our Leiden researches upon
the resistance of metals at low temperatures, according to which it
was imagined that the resistance would attain a minimum as the
temperature was lowered and would become infinitely great at 7’—= 0,
in consequence of the assumption that the electrons which are the
actual conductors in metals would, as was expressed by me in 1904,
begin to precipitate on the atoms as a vapour on being cooled to
( 1110 )
hydrogen temperatures, or as Kornicsbercer — in a manner leading
to a similar dependence upon temperature explains the pheno-
menon that was then supposed to exist, by the recombination of the
electrons that had been freed by dissociation. I already questioned
ihe validity of this assumption with respect to its application to
perfectly pure metals at hydrogen temperatures, when the latest
experimental results (Comm. by Kamertincu Onnes and Cray) obtained
with extremely pure gold showed that the point of proportionality
would always have to be sought at still lower temperatures. It is
now quite clear that in the case of metals like gold and platinum
at any rate that theory must be dropped. If seems that the
free electrons in the main remain free, and it seems to be the
movable parts of the vibrators that are now bound, their motion
at ordinary temperature forming the obstacles to conduction ; these
disappear when the temperature is lowered sufficiently as the vibrators
become then practically immovable *). There is, in the meantime, no
oceasion to ealenlate, unless for still much lower temperatures which
cannot just yet be realised, a “latent heat of vaporization” or a
“dissociation constant” for the electrons for the case of pure metals
of the type treated.
The marked decrease in the resistance until it becomes practically
zero at a temperature just above 4° k. and its remaining at this
value as the temperature is lowered further as has been shown over
a range of about two and a half degrees, so that, as far as resistance
of these metals is concerned, the boiling point of helinm is practically
the absolute zero, points in another direction. It seems to me to be
connected with the change with temperature of the heat energy of
molecular motion of solid substances that has been deduced by ErstTErn
in his theory of the specific heats, on the assumption that it is the
energy of vibrators determined by radiation equilibrium.
In particular an obvious assumption to make is that the mean
free path of the electrons which provide conduction is determined
by the elongation of the above mentioned vibrators. To further
illustrate this point let us keep as closely as possible to the theory
of electrical resistance of Riscks?), Druprn and Lorrmntz, who has
developed it into a pure theory of electrons. We take the formula
1 & NLg
aie etl
1) That the vibrators become practically immovable represents what we have
formerly called the ‘freezing’ of the electrons.
*) Riecxe, Physik. ZS. 1909, p. 512
111)
where y is the electrical conductivity of a cube of unit volume,
N the density of the free electrons, /, their mean free path, 9 their
molecular speed, and ¢ the speed of light, « the elementary charge
and «7’ the kinetic energy of a free electron while 7’ is’ the
Wee? G
absolute temperature. Putting p=, , —, this becomes
Oy fies aV 1
DNL
TAP
, Bp VT s ;
and according to Rigeke if g¢ = . Where a is the distance
a (1 + fs)?
between the atoms supposed to be cubically arranged, s the ordinary and
T the absolute temperature of the melting point, 3in Riecke’s notation the
: | sf i
coefficient of linear expansion, 1 — ——. Instead of this hypothesis of
iy
Rurckr’s we shall put
L=—
. VE
in which
= Br
Bio
=
Pao
where 8 = 4.864.10—-!!, now represents, according to PLanck, the
energy of a vibrator whose frequency is r. The product Br we will
call as usually is done a.
We then get for the ratio of the conduetivity 7, at any tempe-
that at 0’ C. the value:
1s V Tuc. E£ore
% WE?
This formula gives, in fact, good expression to the decrease with
rature 7’, to y
0
temperature of the resistance of pure metals of the kind here consi-
dered (monatomic 7). It shows in the first place the decrease to zero
at a temperature above the absolute zero. For py =a = 54 the
resistance at helium temperatures becomes about O.O000L times
that at O°C.
a E
If we may further assume that 7s already small at O0°C., then the
resistance my at 7’ in terms of the resistance 2, at O°C. becomes
T 0
wD Se |
0 De |—= —
4
pit i 2 Fag
In fact, at O°C. the temperature coefficients of the resistances of
pure metals are, as a rule, greater than 0.00367, and, for platinum,
gold, silver and lead they lie in the neighbourhood of 0.00389
and 0.0040.
And lastly, the formula also expresses well the fact that the
diminution of resistance diminishes in quantity at hydrogen tempe-
ratures, and that in greater degree for substances of high melting
point than for those of low melting point.
An accurate numerical equation, however, such as to determine
even the bend in the curve that represents thé resistance as a fune-
tion of the temperature can be obtained only on the assumption
that smaller values of » and, therefore, of a come in the front at lower
temperatures. Definite values, indeed, cannot be ascribed to ». Erystnin’),
for instance, deduces from its elasticity «== 200 for silver (for he
gives 2= 73.104 em. for the wave-leugth in vacuum corresponding
to v), while Nurnst*) from the specific heat, deduces the value
a — 162 corresponding to 2 = 90.10~4, a number, however, which
is not of itself sufficient to represent the whole behaviour of silver.
For lead, Nernst gives @ = 58, while Einstein gets a = 104 from the
elasticity. Moreover according to the elasticity @ should inerease
somewhat at lower temperatures, while from the specific heat, it
would appear that the change should take place in the same sense
as that in which the resistance changes This, too, shows that the
theory is still far from perfect.
As there exists so much uncertainty, and as it is more a question
of showing that the introduction of vibrators leads to a qualitative
explanation of the sense in which the observed change of resistance
deviates from proportionality to temperature, I have taken for a
one half of each of the values obtained by Erysteim from the elasti-
city. In this way we obtain for a:
for Pt 111, Ag 100, Au 92, Pb 54.
It appears, therefore, that there is indeed a qualitative correspon-
dence *). Before we can attach any greater importance to it, howe-
1) A. Enstemx Ann. d. Phys. (4) 34 (1911) p. 170. Since the address delivered
in the December meeting was only ready for printing in the number of the Dutch
Proceedings for February 1911, I have been able to add then the following calcu-
lations from the elasticity to what I communicated in December.
2) Gf. also Mapverune, Gott. Nachr. 1909, p. 100, who was the first to calculate
the period of molecular vibrations.
3) The numbers are all taken from the Leiden observations (/KameRLIxcH ONNES
and Cray |. c.) and they refer to the purest of the wires, while the probable
negative correction for the influence of admixture and for the results of treatment
during manufacture necessary for its expression in terms of the pure metal have
Wy
Lae
i T platinum silver pela lead
218.1) | 6 | Auipomimcminon seule
379 86 1.365 1.405 | 1-401 ) 1-411) | 1-397 1.384 |
Pipl {hale il il Ie ihe ile i il 1G
169.29 0.617 0.579 | 0.581 | 0.583 0.581 0.586 0.593 0.601 | 0.594
77.93 | 0.285 | 0.213 | 0.199 | 0.220 | 0.197 | 0.225 | 0.219 | 0.250 | 0.253
20.18 0.074 | 0.012 0.014 | 0.015 0.009 0.018 0.008 0.035 | 0.030
13.88 0.054 0.003 0.010 | 0.004 0.007 0.005 | 0.003 | 0.015 | 0.012 |
4.30 0.016 9.000 | [0.009]) 0.000 0.000 [0.002] 0.000
ver, it would have to be shown that the ratio of heat conductivity
to electrical conductivity at hydrogen temperatures *) satisfies the
conditions imposed by Ruecks’s modified theory °*).
At all events in developing new theoretical considerations it seems
desirable to take into account the result obtained *).
I eratefully record my indebtedness to Dr. C. Dorsman for his
intelligent assistance during the whole of this investigation, and to
Mr. G. Hotst, who conducted the measurements with the Wuear-
stone-bridge with much care.
been omitted. The influence of admixture is such as to give vise Lo impediments
distributed, at distances delermined by the quantily of admixture present, throaghout
the metal, which exert an influence upon the mean free path of the free electrons,
that is propcrtional to ! 7’ and therefore an influence on the resistance that is
independent of the temperature just as mixed crystals do in alloys.
Estimating for mercury @ 30 on account of its lower melting-point, we get
the following multiples of the value extrapolated to 0° C. from observations on
the solid state (loc. cit).
ihe OO MKe. 20°,8 K. 13°,88 K.
caleulated 0,263 0,050 0,027
observed 0,264 0,056 0,033
1) Experiments to elucidate this point have been in preparation for some time.
2) An assumption that may obviously be made is that the energy of the vibra-
tors determines the increase of volume from the absolute zero, with which the
explanation of the relation between expansion and change of resistance on one
hand, and between expansion coefficient and specilic heat on the other hand, deserves
to find a place in the theory.
*) The further question calls for attention that is suggested by it regarding the
peculiarities of the motion of electrons through conductors when, by taking all
precautions, the mean free paths are as large as must, in the meantime, be assumed that
they can be made (and begin to be comparable with the thickness of very thin layers).
C Hit}
Physics. “Tonization of gases by light, emitted from GwissLER
tubes. Research after the eaistence of selective effects in the
ionization.” By HH. G. Caxneairir. (Communicated by Prof,
We Lions):
Since Haniwacus’') discovery that an insulated, negatively charged
zincplate loses its charge, when ultra-violet light falls upon it, this
property of the ultraviolet light has been a subject of research to
many observers. Several solids and liquids prove photoelectric, ,i.e.
when exposed to the light they send out negatively charged particles,
Whereas they acquire a positive charge themselves, if they were
uncharged at first.
On gases too the ultra-violet light has an influence. When the
light shines through them, they acquire conductivity ; the light ionizes
the gasmolecules.
If we put the question, how we are to figure the action of the
ether-vibrations on the molecules of substances, which led to the
loosening of negatively charged particles from them, we are inclined
to take it for an effect of resonance. If the molecules of the sub-
stance, solid, liquid or gas, on which the light is stining are struck
by vibrations, the period of which corresponds to those which the
electrons in. the molecules can emit themselves under certain circum-
stances, then the electrons will by resonance get so strong a motion,
that they are loosened from the molecule and will behave like free
particles.
From this point of view we may expect that, if a given substance
in the luminous state emits electrically acting vays, this same sub-
stance, when struck by these particular rays, will be more photo-
electric, than when it is under the influence of rays from any other
source of light; also we may take for granted that, examining the
effect of the radiation, emitted from the above mentioned source
of light, on different subsiances, including the substance emitting the
active rays, the effect on this latter substance, when compared
to that on the other substances under examination, will be found
the strongest.
If we use as sources of light discharge tubes filled with different
gases, and examine the ionization excited by the light in the same
gases, then it will be possible for us to arrange them in a definite
order, according to the measured effect, which order will depend
1) Wied. Ann. 33, 301, 1888.
el ree e
(1115 )
on the source of light we have used. It may be expected, that
when the ionisationroom contains the same gas which fills the
discharge tube, this gas will be more influenced by the ionizing
rays than any other.
In the following pages a short account will be given of a research
after the existence of similar selective effects in the ionization of
gases under the influence of light emitted by Geissler tubes. For
particulars we refer to a dissertation which is to appear within a
few weeks.
Three methods may be followed in order to find out whether
ions are formed in a ges by radiation. Firstly we can show the
existence of ions in damp gas by condensing the aqueous vapour on
them. Secondly we can make the gas pass along a charged conductor
or through a condensator after it has been struck by the ionizing
rays; if the gas has got conductivity the conductor or the condensator
will be discharged. And in the third place, if the gas under
examination is at rest between the plates of a condensator or in
the neighbourhood of a charged conductor, then there will be a
current in the condensator, or the conductor will lose its charge,
when the radiation has caused ionization.
In using the former two methods the risk of erroneous results
by photoelectric action on minute drops of water or floating dust
particles is greater than in using the third; therefore the latter
method was chosen for the research described here. Moreover it
makes it possible for us to measure the ionization at different pressures
in the gas under examination.
The apparatus used for the experiments was made of glass and
consisted of three separate partitions, viz. the discharge tube, the
absorpuionroom and the ionizationroom. Composed in this way it
gave an opportunity for examining the absorption of different gases
for the ionizing rays and so made it possible for us to study an
eventual connection between ionization and absorption, besides to find
out the possible existence of selective effects in the absorption also.
The ionizationroom, or condensatorroom, forms a separate part of
the apparatus. It is closed on one end by a ground-in basin-shaped
piece of glass, the bottom of which is a fluorite plate of 15 m.M.
diameter and 3 m.M. thickness. On the other side a glass plate is
cemented against the ground edge. In this plate are two holes, shut
by amber plugs cemented into them, which are at the same
(daati6; +)
time the bearers of the conden-
sutorplates. The wall of the con-
densatorroom, ground at the out-
side, forms the cone of a ground-
in joint, the neck of which is
the end of a evlindrieal tube
forming the principal part of the
apparatus. On this neck is made
a stop-cock ; in the wall of the
condensatorroom there isa little
hole, whieh can he placed oppo-
site the stop-cock. In this way
we can exhaust the room be-
tween the condensatorplates and
fili it with the different @ases
under research.
In the other, straight end of
ihe above mentioned cylindrical
iube the discharge tube is cement-
ed in. The open space between
the discharge tube and the ioni-
zatiouroom forms the absorption-
room. By means of a stop-cock
this room too can be exhausted
and filled with other gases.
The discharge tube was made
in the way deseribed by Lyman’),
with internal capillary and ring-
shaped aluminium electrodes. It was closed by a fluorite window,
20 m.M. diameter, 3 m.M. thick, and provided with a glass mantle
fitting in the cylindrical tube of the apparatus. A pair of electrodes
in the absorptionroom were not fit for use because of photoelectric
effects presenting themselves.
The arrangement of the apparatus insures perfect air-tightness
of both ionization and absorptionroom. The distance between the
fluorite windows of the discharge tube and the ionizationroom was
regulated in such a way that no rays from the discharge tube could
strike the plates of the condensator, in order to prevent mistakes by
photoelectric effects on the electrodes in the ionizationroom.
As during the examination no changes may take place in the
1) Astrophys. J. 19, 181, 1906.
Galati)
discharge tube, the fact that many gases in the discharge tube
combine with the metal of the electrodes under the influence of the
discharges, or, if they are compounds, break up into their components,
is the reason that only a limited number of gases are fit for a
research as is here described.
Therefore hydrogen and oxygen are chosen for our research; we
have also tried to get comparable results with carbon monoxide,
notwithstanding the peculiarity of this gas to vanish in the discharge
tube by the beforesaid reason.
In order to diminish as much as possible the troubles caused by
this process, the discharge tube was provided with a reservoir measuring
ten times the tube itself. A copper box could be put around the
reservoir; by heating this box with a heating spiral the gas in the
reservoir could be heated, and so the pressure in the gas could be
increased, if it had decreased by the selfexhansting process.
We studied the ionization by radiation with the three sources of
light in the same three gases and besides in air and oxygen. The
absorption was examined as well, and also the way in which effect
and absorption change, if the pressure in the gas is lowered.
The measurements were made with a Cremer—EpmELMANN string-
electrometer.
One of the plates of the condensator was kept on a constant
potential varying from 20 tot 320 Volts, the other was connected
with the electrometer. The system condensatorplate + electrometer
was put to earth; the earth connection could be broken quickly by
a special device. If under the influence of the radiation the gas
gets conductivity, the insulated plate begins to charge itself. The
rapidity with which this happened gave the rate of the conductivity
in the gas. The time the system needed to charge itself to a certain
potential was measured with a stopwatch.
The capacity of the system condensatorplate + elecirometer was
18 ¢.M. A rapidity of charge of 1 Volt per sec. corresponded with
a current of 20> 10—!? Amp. in the condensater. The exactitude
50 /
reached in the measuring was 5°/,
The expectation that the research would show selective effects
in the ionization of gases has not come true. The effect caused by
the hydrogen radiation as well as by the nitrogen and carbon monoxide-
radiation proved dependent on the pressure of the gas; whereas the
mutual proportion of the effect on the different gases was found to
vary with the pressure in the gas. The value of this mutual proportion
Lg al? 3
iv
Proceedings Royal Acad. Amsterdam. Vol. XIII.
_ 2 ET LTT
Pr oport.
of the Ho Ho | CO
measured] CO
effect
caused by
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300 , 1.66
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200
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RADIATION OF HYDROGEN, PRESSURE IN THE TUBE 1.2 mm.
iF
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RADIATION
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H | | Absolute value
2 of the effect
Oz | | on hydrogen
3.1>< 10-12 Amp,
4.3><10-10 ,
5.6 <10—12) 5
6:9 <0
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13.6><10—12 |
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OF CARBON MONOXIDE.
= 0.156><10—12 Amp.
i 0.295<10—12 =
Res 0.291><40-=255
= 0.348X<10-l2 ,
aie 0.420 10-122,
0.540<10-12 ,,
OF NITROGEN.
300s --
100,
50 Abo
20 1.47
ORs 1.44
yey 1.41
LOs, O.98
low | 0.66
)
1.82
|
1.49
0.89
0.87
|
0.74
0.681
0.695
0.710
1.02
51
1.60
1.14
1.06
0.90
iPoo
0.47
0.55
0.61
0.67
1.13
1.15
0.625
0.800
0.875
0.941
1.11
0.754
1) “Low” means here that the pressure in the condensatorroom
= 0.054<10—-"Amp.
= 0.066 10-12,
_ 0.069X<10-22 ,,
= 0.07210-)2 ,,
— 0.09010-12_,,
_ OF120 10S
was less than 0.1 mm.
(alas)
under different circumstances is given in the additional table. This
table shows that, when the pressure is high, the ionization is always
strongest in hydrogen, and after that in carbon monoxide, nitrogen,
air, oxygen. If the pressure in the gas under examination is lowered,
the proportion changes. Concerning this change may be said that the
curve representing its character shows in all gases an ascent, slow
under high pressures and sharper under lower ones. Under very low
pressures a slight decrease of pressure shows a considerable increase
of the effect.
The table mentions the results of the observations made with two
hydrogen tubes filled at different pressures; further with a carbon
monoxide, and a nitrogen tube. The first, second, and third columns
refer to the proportion between the effect measured resp. on hydrogen,
carbon monoxide and nitrogen, and the effect observed in the two
other gases the radiation of which has been examined. The fourth
column gives the proportion between the effect on hydrogen and that
on air and oxygen. In column N°’. 5 are given the absolute values
of the currents measured in hydrogen. The character and the rapi-
dity of the increase of the effect with decrease of the pressure in
the gas may be judged therefrom. The numbers are interpolated ;
they do not refer to observations made at just the given pressure.
The conditions in the absorptionroom were always alike ; the pressure
in it was always so low that the active rays were not absorbed.
BR) Ry As TAY
In the Proceedings of the Meeting of March 25, 1911:
p. 942 line 17 from the top read: Method. First Part. The Densi-
meter.
OA Gy eh , bottom ,, : Method. Second Part. The
V olumenometer.
55 OE ois ype “ » : for “In“this we’, read: ‘““We’’.
, 949 , 12 ,, ,, top : for.Hxperimental method, read:
° Course of the experiments.
(April 20, 1911).
Phil, it } Be WA Mi ay Hie ‘; if? tt
Om, BA Re a ae ae Deh ey
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‘
KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN
TE AMSTERDAM.
PROCEEDINGS OF THE MEETING
of Friday April 28, 1911.
—ADOGe—
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundive
Afdeeling van Vridag 25 April 1911, Dl. XIX).
(S) @yaNy SE Aap ANS Aas
L. Rurrex: “On orbitoides in the neighbourhood of the Balik-Papan Bay, East-coast of
Borneo”. (Communicated by Prof. C. E. A. Wicumany), p. 1122. (With one map).
G. C. J. Vosmarr: “Observations on the genus Spirastrella”, p. 1139.
7. G. Dusser pe Barenne: “The action of strychnine on the central nervous system. ‘The
segmental, strictly localized strychnine-intoxication of the dorsal spinal mechanisms: a
contribution to the dermatomery of the hind leg in dogs”. (Communicated by Prof.
C. WiykKLER), p. 1146.
BP. A. I. Scurememakers: “Equilibria in the system: Water—Sodium sulphate—Sodium
chloride—Copper sulphate—Cupric chloride”, p. 1163.
P. vay Rompurcu: “Hypaphorine and the relation of this substance with tryptophane’’, p. 1177.
D. pe Vries Remixcu: “A new method of determining the arterial bloodpressure in man; at
the same time an attempt at estimating the influence of the arterial wall on it”. (Communi-
cated by Prof. K. F. Wenckepacn), p. 118i. (With one plate).
N. L. SéuxGen: “Vipase produced by microbes”. (Communicated by Prof.M. W. Brwerincn),
p- 1200. (With one plate).
J.D. van ber Waars: “On the value of the critical quantities”, p. 1211.
C. Braak: “Ou tdal jorees as determined by means of Wirciert’s vstatic scismograph”.
(Communicated by Dr. J. P. van DER Srox), p. 1231.
M. W. Bewerrinck: “An experiment with Sarcina venirienli”, p. 1237.
W. Karreys: “On the centra of the integral curves which satisfy differential equations of the
first order and the first degree”, p. 1241.
J. D. van pkr Waars: “Some remarks on the value of the volumes of the coexisting phases
of a simp!e substance.” I, p. 1253.
W. H. Jurius: “The lines H and K in the spectrum of the various parts of the solar disk”,
p. 1263.
Il. Kameruixcn Onnes: “Further experiments with liquid helium. C. On the change of
electric resistance of pure metals at very low temperatures ete. IV. The resistance of
pure mercury at helium temperatures”, p. 1274.
Errata, p. 1276.
74
Proceedings Royal Acad. Amsterdam. Vol. XIII.
‘Ciepes
Geology. “On Orbitoides in the neighbourhood of the Balik:
Papan Bay, East-coast of Borneo.” By L. Rurren. (Commu-
nicated by Prof. A. Wichmann).
(Communicated in the meeting of February 25, 1911).
During a four months’ exploration near the Balik-Papan Bay
executed by order of the ‘Nederlandsche Maatschappij tot het
verrichten van Mijnbouwkundige Werken’, the general geological
results of which are described elsewhere, I collected rocks containing
Foraminifera in several places.
With the consent of the Director of the Department of Agriculture,
Mr. Lovink I could make a thorough study of part of these fossils
in the laboratory for geological observations at Buitenzorg, where
the superintendent Dr. J. Mour, with the greatest affability, set a
room apart for me and was constaitly ready to lend me a helping
hand during the investigation.
I regret I had to dispose neither of sufficient time, nor of suffi-
cient literature to be able to determine all Foraminifera ; the greater
part of the work was devoted to the Orbitoides which ocenrred in
different species and a great number of specimens among my material.
Together with the description of the Orbitoides, likewise the other
Foraminifera will be mentioned, in so far as they could be determined.
For orientation a sketch-map on a seale of 1.250.000 is added
to this communication, on which the places where the fossils have
been found, are indicated, the principal ones by crosses, the others
by circlets. Whereas Foraminifera occur chiefly in pure limestone
or in hard mar], in which they can only be seen distinctly in thin
sections, I succeeded in finding looser marl, from which the Fora-
minifera could be washed ont in great quantities. The first place
lies on the Sungei (river) Palamuan, about 2 km. west of the
kampong of that name, the second on the Sungei Blakin, the last
on the upper-course of the Sungei Mentawir. These three places are
indicated on the map by a cross. Of these three places the one on
the Sungei Pamaluan is the oldest, that on the Sungei Mentawir the
youngest. The greater part of the Foraminifera collected at these
spots is in the collection of the Mineralogical-Geological Institute of
the University of Utrecht; during my investigation I only disposed
of small specimens which I had left behind here, so that it is not
impossible that the chief material contains still some other forms
than those 1 am about to describe.
The greater part of the forms 1 am going to describe, come from
the three places mentioned; I found only one species in a limestone at
( 1123 )
the declivity of the mountain-range where is the source of the
Sungei Sepaku, which is as old as the strata on the Sungei Pama-
luan; Orbitoides were likewise found in marl in Pulu Balan, on
the Sungei Binuwang, and in the delta of the Sungei Pamaluan, but
these were not distinct enough to allow a specific determination.
As all Orbitoides found belong to the subgenus Lepidoecyclina and
to the still younger, new subgenus Lepidosemicyclina, all strata are of
a posteocene age *).
A very great number of sorts of Lepidocyclina of the Indian
Archipelago has already been described; I shall try to group these
species in such a way as to give an easy survey of them, I am
however quite aware of the fact that most likely I shall not fully
succeed in this respect, on account of insufficient knowledge of the
literature and inaccessibility of a great number of publications which,
though not directly relating to the Indian forms, are nevertheless of
great importance for the knowledge of Orbitoides.
Among the Lepidocyclina known in India some are easily distin-
guished because they are not round but star-shaped and even poly-
gonal; one form is characterized by the appearance of several strata
of median chambers, whilst both, the very large and the very small
ones, can be easily separated from the others. The greatest difficulties
offer the species with normal forms and average sizes.
If in this communication numbers are given about the dimen-
sions of Orbitoides d always means the horizontal diameter, / the
height (thickness).
1. Species of polygonal or radial form. To these belong O. radiata
Martin®) QO. Martini Scutumpercer*), both of Java and perhaps
O. murrayana Jones and Cuapman ‘), of Christmas Island. O. radiata
has an undulated circumference, the diameter is 8 m.m., O. Martini is
purely star-shaped, the maximum-diameter is 6 m.m., O. murrayana,
of which only a horizontal section is known, is quadrangular ; d is
9,375 mm. Douvi1é has however rightly pointed out *) that the
latter form is perhaps not star-shaped or polygonal at all, but round
and bent strongly saddle-shaped, so that the horizontal section must
obtain a polygonal or star-shaped figure.
Marti, Sammi. d. Geol. Reichsmuseums of Leiden, 6. p.132—245, 1902.
Martin, Die Tertiiirschichten auf Java. 1880.
C. ScutumBercer, Samml d. Geol. Reichsmuseums in Leiden, 6, p. 128—134. 1901.
T. Rupert Jones and I. Gaapmam, On the Foraminifera of the Orbitoidal
Limestone and Reef Rocks of Christmas Island, in: C. Anprews, A Monograph
Christmas Island, 1900, p. 226—264.
5) H. Douvitté, Bull. Soc. Géol. de Wrance (4) 5, p. 435—465. 1905.
74%
Ke
2) K.
3)
)
( 1124 9
2. Species with more than 1 stratum of median chambers. As a
form of this nature has only been described O. multipartita Martin’).
The median chambers oecur only in more than 1 stratum at the
periphery, where the lateral chambers are reduced; dis about 7 mm.
Only the form found in Java has been described. It is however my
opinion that two forms of Christmas Island described by Jonns and
Cuapman (Le.), ie. O. insulae natalis var. inaequali and O. ephippoides
should likewise be classed among O. multipartita. In the former one
distinctly sees in the representation several strata of median chambers
at the periphery, whilst the embryonal ventricle is large, as with
Q. multipartita. For the rest Douvitné has pointed out already that
there was no reason for the introduction of anew species: O. ephip-
poides (l.c.).
3. Small species. The oldest description known of these is O. Suma-
trensis Brapy?), which is nearly globe-shaped, d 3, h 1'/,—*/, mm.
The median plane forms at the periphery a thin keel; only small
macrospherie forms are known *) with certainty ; of the microspheric
forms it is only occasionally mentioned that they can reach 15 m.m.
diameier *). Nias ?), Sarawak *), 5. Borneo *) and Christmas Island ‘).
K. Marrin*) has described a very small form of Timor but not
given it a name, which seems in the main to be similar to O. Suma-
trensis Brapy, in the middle the scale becomes gradually thicker,
and the embryonal chamber and the succeeding one are very large,
the Timor-form is only somewhat smaller and less globular: d1—2,
h 1\—'/, mm. Timor (Gunune InHavuw), S. Borneo’) New Guinea’).
Another, very small form of Timor‘), however, differs decidedly
from O. Sumatrensis by its flattening. For convenience’ sake we shall
indicate it as O. Timor 1.
Somewhat larger is a form deseribed by Brapy *) as O. dispansa ;
afterwards VerBEEK and FENnNeMA ’) proved this determination to be
1) K. Marvin, Die Fossilien von Java, Erstes Heft. 1891.
2) H. Brapy, Jaarb. v. h. Mijnwezen in Ned. Indié, 7, p. 157— 169, 1878.
8) R. Butnen Newron and R. Hontanp, The Ann. and Magazine of Natural
History (7). 3, p. 245—264, 1899.
') H. Douvitts, l.c.
5) T. Rurert Jones and I’. Cuapman, l.c.
6) K. Martin, Samml. des Geol. Reichsmuseums in Leiden, 1, p. 1—64, 1881.
7) K. Martiy, Samml. des Geol. Reichsmuseums in Leiden, 1, p. 131—193, 1883.
8) K. Martin, Samml. des Geol. Reichsmuseums in Leiden, 1, p. 65—83.
%) R. Verpeex et R. Fennema, Description géol. de Java et Madura, p. 1176 —1182,
1896.
(1125 )
incorrect, and determined it as their O. 1A. d6,42mm. The disk
is in the centrum gradually thickened, and on both sides covered
with warts (on Brapy’s representation I count about 40 of these).
Afierwards as a new sort of Christmas Island QO. neodixpansa las
been described by Jones and Crapmam'), the diagnosis of which
O. dispansa Brapy and O. 1A Verperrk and Frennema (5, h 1*/, mm.)
This O. neodispansa consequently seems to occur in Christmas Island‘),
Nias '), Padangsche Bovenlanden') and Java.
At all events 0. 2C’ and O.2D Verserk and Frnnema ') differ
from this O. neodispansa, the former of which is megalospheric, the
latter microspheric, according to the representation the scale is
quite smooth and provided with a central tubercle, ¢ 5—6 h 2 mm.
Java.
At last the megalospheric form of O Tournoueri Lem. et Douvitié
(¢4-—5 mm.) which has only a few warts in the centrum, belongs
to these small forms. ’).
4. Large Forms. A great many large Orbitoides from the Indian
Archipelago have been described, which, as they are not yet com-
pletely known, can be determined either with great difficulty or not
at all. To these belong O. gigantea Martin *), O. Cartert Martin *),
O. 3 E and O. 3 F Vurperk and Frennema'), all of Java. Of the
latter two, the former is again micro- the other megalospheric. Most
likely a few more are hidden among these two sorts, as for their
horizontal diameter is given 4'/,—70 mm., which is certainly a too
ereat variability. A common property is the spatulate form of the
median chambers, on horizontal section and their large dimensions
(max. 0.250 mm. radial with 0.2000 mm. tangential), which is much
more than with the evidently allied O. Mantelli.
Another gigantic incompletely known Orbitoid which consequently
did not receive a name, is found in Great-Kei (d 70 mm.)'). Two
large, incompletely known forms are found in Timor’), one of these
has median chambers as O. Mantelli Mort *).
A pretty large Orbitoid of Christmas Island QO. imsulae-natalis
was first, very incompletely, and only on account of the vertical
1) Vide previous page.
2) K. Marin. Die Tertiairschichien auf Java 1880.
3) K. Marrin, Samml. des Geol. Reichsmuseums, Leiden, 1, p. 8—64, 1881.
( 1126 )
section, described by R. Jonus and Cnapman '). Afterwards Scnium-
BERGER *) has applied this name to a well-known form of Java, the
thin section of which corresponded very well to the form of Christmas
Island d@ 12—19 mm. 4 5 mm. Skeleton columns very fine with
little warts at the surface. This form is likewise known in Borneo’)
and Sumatra *).
A rather large form of O. formosa first described by SCHLUMBERGER")
as OU. formosa is likewise well known. From the sections (he found
the Orbitoide in hard lime-rock), he concluded that he had to do
with a radius-shaped Lepidocyclina, but Dovvi.Lé*) showed that the
Orbitoide had a very pronounced saddle-shape, and consequently
gave a radius-shaped horizontal section —- megalospheric, median
chambers on horizontal section half-circle-shaped, lateral chambers
separated by very thin horizontal parietes @ max. 18, 4 2 mm. At
the surface no warts are found. Borneo *), *), and Celebes *).
The microspherie form of O. Tournoweri Lem. and Dovv. is like-
wise large and according to Douvit1é *) likewise smooth.
5. Orbitoides of average size. Not many forms of average size
remain. Brapy°) described from the Padangsche Bovenlanden an
Orbitoid as O. papyracea, afterwards Verseek and Fennema*) proved
the incorrectness of this determination and called the form which
they knew likewise from Nias 0. 1 5. Newton and Ho..anp‘)
found. this Lepidocyclina back in Sarawak and christened it O. Ver-
BEBKI. They found there both the microspheric form, and the macro-
spheric one, the former is the larger d 5—12 mm. h 1'/,—2 mm.
By the smooth surface and the gradual thickening towards the centrum
this form is sufficiently characterized; it can only be mistaken for
QO. formosa. Incidentally O. Verbeek is likewise mentioned from
Christmas Island *).
1) T. Rupert Jones and F. Cuapmaw, l.c. p. 242-—243.
2) CG. ScutumBercer, Samml. des Geol. Reichsmuseums in Leiden, 6, p. 128—
134, 1901.
3) H. Douvitts, |.c.
') CG. ScuLumpercer, Samml. des Geol. Reichsmuseums in Leiden, 6, p. 250—
253, 1902.
5) H. Brapy, l.c.
6) R. VERBEEK et R. fenNEMA, l.c.
7) BuLLEN Newton and Houuanp, l.ec
8) Jones and CHapMay, lc.
( 1197 j
At last, though very incompletely, a new species from Christmas
Island is described by Jones and Cuapman as QO. Andrewsiana.
There is only a median tubercle d 9.75 mm.
At last from a great number of places the subgenus Lepidocyclina
is mentioned, the forms however could not definitely be determined,
these places are Java'), N. W. Guinea’), Koor’), Batjan*), Obi *)
and the Philippines ‘).
Of all authors only H. Dovvii.¥ has tried to make use of the
Indian Lepidocyclinas as leading fossils, in doing which he supports
himself on experience gathered elsewhere. He gives the following
table :
Burdigalien L. Toarnoueri, lL. sumatrensis.
Aquitanien sup. L. insulae-natalis.
Aquitanien inf. L. fermosa.
Stampien L. formosa, with Nummulites subbrongniarti.
In the following description of our material we shall combine
the sorts that belong stratigraphically together, beginning with the
oldest, so that we shall be able to see, whether our results agree
with those obtained by DovuviL.E.
O. (Lepidocyclina) aff. formosa SCHLUMBERGER.
In a lime-marl, about 2 km. West of the Kainpong Pamaluan
occurred, besides small Orbitoides, other Foraminifera and corals,
many splendidly conserved large Orbitoides, which could be washed out
in toto from the marl, so that it was easy to prepare orientated
sections.
The seale is flat, circular (d. 23 mm.) and provided with a median
tubercle (d 4 4 3.5 mm.). Most seales are flat, some however show
a saddle-shaped bend. At the surface one easily discovers the lateral
ventricles bordered by polygons, whilst at the edges one can here
and there see the median chambers dimly shining through. Scarcely
any vestiges of skeleton-columns are to be seen at the surface.
Horizontal section. Two horizontal sections have cut the median
chambers in various sectors. These are more or less spatulate. The
embryonal chamber is not touched; it must however be very small,
1) K. Martin, Samml. d. Geol. Reichsmuseums in Leiden, 6, p. 135—245, 1902.
2) K. Martin, Samml. d. Geol. Reichsmuseums in Leiden, 1, p. 65—S83.
3) K. Martin, Samml. d. Geol. Reichsmuseums in Leiden, 7, p. 225—230, 1904,
4) K. Martin, Centralbl. f. Mineralogie etc. 1901, p. 326—327.
(125) )
as the other chambers reach to the immediate vicinity of the centrum.
Most of the central chambers that are next to the embryonal one
are flattened in a radial direetion, the radial diameter is 40—60, the
tangential one 60—80 uw. Only farther towards the periphery the
median chambers become pretty regularly six-angular, whilst the
most peripherie ones are spatulate. In general the size of the chambers
increases towards the periphery, but occasionally rings of smaller
chambers oceur between larger ones. Whilst by far the greater part
of the median chambers are ranged in circles, their arrangement
in the centrum is a littke more irregular, and at the periphery
sometimes not continued eurves are linked between the continued
coneentrie circles. The number of concentric circles of median
chambers amounts to more than 100. The radial diameter of the
peripheric chambers is 150—250 u, their tangential diameter 140—
150 nw. Especially at the periphery the parietes of the median chambers
show a typical structure (fig. 1). The
parietes namely consist of a dark
untransparent central lamella to which
granular, grey calcite sticks. In this
section the central lamella is not
continued round the chambers, but
consists of a tangential, peripherial
curve, two tangential, central parts
of a curve (each the half of a tangen-
tial peripherial curve of chambers
placed wore towards the centrum)
and of two radial lamellae, ending
towards the centre in a tangential
Fig. 1. curve. Perhaps there is above this
little curve a porus of a tangential shape uniting the chambers of
the same curve. In many ventricles the central lamella is on all
sides covered by symmetrically thick secondary parietes, in others
these secondary parietes are thinnest on the tangential parietes.
Vertical section. From this section appears likewise that the
embryonal chamber must be very small, though it is not visible
itself. The height of the median chambers namely decreases from
the periphery to very close to the centre from 120 to 60 «. The
peripherical parietes of the median chambers are always convex to
the outside, the structure of the parietes is only very unsatisfactorily
visible. The lateral chambers have very thick parietes, and are
strongly flattened in a vertical direction; their height is 80—50 uw
the thickness of the parietes 30—40 wu. Because the parietes are
( 1129 )
regularly laterally interlocked, more or less vertical thickenings of
the parietes are formed slightly diverging from the centre, which
are imperfectly developed skeleton-columns. On either side of the
median plane are in the centrum about 20, at the periphery only
5 strata of median ventricles.
In a dense, grey limestone, which is found half way to the top of
the range of mountains containing the spring of the Sepaku, I found
many Orbitoides, showing in the main great resemblance to those
just described. The shape of the median chambers, the structure of
their parietes, their dimensions and likewise the shape and situation
of the lateral chambers are completely alike. The largest diameter
is 23 mm. Only the shape of the embryonal chamber, which like
the second chamber is very large, shows a great difference. Both
these chambers communicate with each other by a very wide opening.
The two described Orbitoides consequently form a distinct pair:
the fossils of the Pamaluan are the microspheric, those of the Sepaku
the megalospheric forms.
There are only very slight differences between tke described form
and Q. formosa. The inferior and rare, saddle-shaped bend of our
Orbitoides is of little importance, it is well-known that in this respect
many sorts are very variable. SCHLUMBERGER (I. c¢.) however reports
about O. formosa, when describing the lateral chambers, that these
are: “tres surbaissées et séparées par de tres minces parois’, whilst
in our form the horizontal parietes between the lateral ventricles are
very thick. S. communicates too little about the shape of the median
chambers to enable us to discover eventual differences with our form.
In the lime-rock of the Sepaku-spring-mountains occurs another
little Lepidocyclina that cannot be more exactly determined, besides
the Orbitoid described; further Globigerina, and most likely Textu-
laria. The limestone is grey and rather transparent on the section ;
it contains here and there microscopic grains of pyrite, which often
fill the ventricles of Orbitoides.
In the marl of the Sungei Pamaluan a few more smaller Lepido-
cyclina were found (5 specimens) whose diameter was only 5 mm.,
in one case even less. The median chambers are rhombic on the
horizontal section, most likely the embryonal chamber is small. The
skeleton-columns at the surface have the appearance of small warts,
the situation and number of which vary strongly even in this insig-
nificant material. In two specimens there was only one central wart,
two others showed many warts scattered all over the disk, whilst in
the last specimen only a few warts lie round the centre. In general
these characteristics agree very well with what is known of O. neo-
( 1130 )
dispansa Jones and Cuarman (O. dispansa Brapy and O. 1 A VerBrek
and Frnnema); the material is however too insignificant to admit of
a reliable determination. It is however of importance that we find
in a level characterized by a frequent occurrence of a primitive
Lepidocyclina, likewise a few representatives of types younger ac-
cording to Dovvitii (lc. p. 449). Perhaps it is likewise remarkable
that these younger forms show here evidently great variety in one
important characteristic, (the wart-shaped appearance of the skeleton-
columns at the surface).
From a lime-marl at the Sungei Blakan by washing a great
number of Foraminifera were obtained, the greater part of which
belonged to Orbitoides. From this rough material the different sorts
could now be selected, and it appeared that in this way strongly
separated series of forms could be obtained, it was but seldom doubtful
among which group a detinite specimen ought to be ranged.
With great application and perseverance my wife performed the
fatiguing work, taking up so much time of washing and selecting
the sorts.
The sorts collected here are the following :
O. (Lepidocyclina) acuta n. sp.
(Leh , L
Of this sort about 50 specimens were found the horizontal diameter
of which varied from 3—7 mm. One sees at the surface the irre-
gularly bordered lateral chambers, whilst at the edge sometimes the
median chambers are likewise visible, as here the lateral ventricles
may be missing. The centre of the disk is taken up by a single
skeleton-column which is sometimes diffuse and variable in size, and
ean likewise consist of an agglomeration of small columns. There
are no other skeleton-columns placed nearer towards the periphery.
The central part of the disk is strongly drawn out in a vertical
direction, so that the Foraminifere is pointed at both extremities,
which gives to this Orbitoid a very peculiar shape (acuta). The
fact that these skeleton-columns are restricted to the lengthened ver-
tical axis is obviously very appropriate. This lengthening in a vertical
direction is however subject to many variations; it can be so im-
portant, that the vertical diameter becomes longer than the horizontal
one (I measured in one case d 3 h 3'/, mm.). The peripheral edge
is with this form always flat never bent saddle-shaped.
Horizontal section. Neither could I observe the embryonal chamber
here; it must however be very small, as the median chambers
reach to the immediate vicinity of the centre. The more central
(1181 )
median chambers are flattened in a radial direction (vad. diam. 17,
tang. diam. 30 w). In these chambers already the parietes are thick
(10 @); only an indistinct central lamella can be observed in the
parietes.
Towards the periphery the chambers become first hexagonal
afterwards spatulate; in these peripheral chambers the cavity of the
ventricle however always remains oval. It is very typical that with
this form, the chambers are placed so irregularly, so that very often
not continued curves are linked between the concentric circles. The
dimensions of the peripheral chambers vary considerably ; radial
65—90 uw tang. diam. 55 uw. The number of concentric rings of
chambers is more than 50 and less than 100. At some places of the
preparations the more delicate structure of the parietes could be
studied. Here likewise a central lamella can be distinguished which
is however often indistinct. The secondary parietes are here sepa-
rated much sharper from the later chamber-filling than with O. for-
mosa, which however may partly be a consequence of the conservation.
Here namely every chamber is filled with single crystal of calcite, whilst
by O. formosa the ventricles were usually filled with an aggregate
of exceedingly fine crystals of calcite. At some places the wide pori
can be seen that lead from one median ventricle obliquely outward
to two median chambers of the ring lying more peripherally.
Numerous pori run from the median chambers vertically or some-
what obliquely upward and downward to the adjacent lateral chambers.
In the main the shape of the central
chambers is the same as with O. formosa;
the radial parts however are continued
here as far as the periphery (fig. 2).
Vertical section. In the vertical section
one sees very distinctly the increase of
the vertical diameter; the strong, central
skeleton-column is especially on one side
: clearly represented. The system of the
. # median chambers consists of only one
Fig. 2. stratum, ihe chambers are low (45m) and
their horizontal parietes are very thick (25 w. The pori between
the median and the lateral chambers are represented here lengthwise ;
it appears likewise that the lateral chambers communicate with each
other by means of many wide, vertical pori, which are partly infil-
tered with a brown mineral containing Fe. The number of strata
of lateral chambers on both sides of the median plane amounts to
about 20.
( 1132 )
O. (Lepidocyclina) flevuosa n sp.
A second form of Sungei Blakin is somewhat less numerous
than the former, I could dispose of about 20 specimens agreeing
very well with each other. The Foraminifera consist of a lens-
shaped body surrounded peripherally by an edge which is strongly
plaited in a vertical direction (flexuosa). The horizontal diameter is
4—7T mm. the vertical one about 5 m.m. At the surface one sees
distinctly, especially in the centre, the wart-shaped extremities of
many not thick skeleton-columns between the lateral chambers
enclosed in irregular polygons.
Horizontal section. On account of the strong bend of the median
plane in a horizontal section of course only irregular areas of median
chambers can be hit. Again the embryonal chamberlet must be very
small; it is however not hit in a single section. The first peripheral
chambers lie irregularly round the centre; those lying farther outside
seem to be placed in regular concentric rings. Near the centre the
median chambers are again flattened in a radial direction; d 40u rad.
and 554 tang. More towards the peripbery the median chambers
become first hexagonal, afterwards rhombus-shaped or spatulate, it
seems that the rhombus-shaped chambers have the majority. The
dimensions of these peripheral chambers are: d 20—120w rad.,
60—100u tang. The number of concentric chamber-rings amounts
to 50—100.
Likewise in this form a primary lamella can be distinguished at
the parietes of the median chambers, the secondary thickenings of
the parietes change here gradually into the later chamber-filling. The
shape of the median lamellas is typical, each ventricle is bounded
by a peripheral arched piece, that
passes into two radial parts whilst
at ihe central side two arched pieces
are found (fig. 3). Pori between the
median chambers could not be dis-
covered with certainty.
The lateral chambers are in this
section likewise enclosed in irregular
polygons, their parietes are very
thick; they correspond by means of
rare, very wide, horizontal pori, whilst
at favourable places one sees exactly
into the openings of numerous ver-
tical pori.
( 1133 )
Vertical section. Whilst in the centre there is but one stratum of
median chambers, they gradually increase towards the periphery,
so that there 2 or 3 strata of median chambers are found. From
the centre several skeleton-columns extend towards the periphery,
others are linked in at half-height. The height of the median cham-
bers in the centre amounts to 25u. The lateral chambers are here
likewise strongly flattened, and communicate with each other by
numerous vertical pori. The number of strata of lateral chambers
at the centre is about 20 or more, at the periphery it is sometimes 0.
The Lepidocyclina described has the greatest resemblance to
O. multipartita Marr., but differs again from it by a smaller size,
greater thickness, inferior extension of the median plane towards the
periphery and by the small embryo-chambers. Neither can O. flexuosa
be regarded as the microspheric form of QO. multipartita, as the
microspheric forms are always larger than the megalospheric ones.
From QO. insulae-natalis the described sort distinguishes itself by its
smallness and general shape, from O. neodispansa by its thickness
and the much less great warts.
QO. (Lepidocyclina) polygona n. sp.
A form that is no longer round but more or less regularly polygonal
(polygona) contrasts very strongly with the two former. It is a little
thin Lepidocyclina (d 1*/,—3 mm., / 0.9 mm.) of a trigonal to hexagonal
shape. At the surface one sees distinctly the irregularly confined
chambers, whilst at the angles comparatively very strong columns
in the shape of warts, are found at the surface. Among my material
there was only 1 specimen with 3 warts, 40 with 5 warts and
13 with 6. As a general rule may be admitted, that the number of
warts and consequently likewise the polygonamy increases with the
size, yet there are many exceptions to this rule.
Median horizontal section. In impure median sections one sees the
irregularly confined, lateral chambers and the skeleton columns,
consisting of an aggregate of crystals of calcite. Here and there pori
running vertically or obliquely upward can be seen between the
lateral chambers.
The embryonal chamberlet is very large, the second chamber is still
larger and partly encloses the former; the exterior parietes of these
two chambers are thick, the separating parietes between these two
chambers are very thin. The maximal diameter of the second chamber
amounts to 800—400 4. Though in. general the median chambers
in this genus are still spatulate, their shapes vary however considerably,
( 1134 )
\
whilst they are moreover placed very irregularly ; it is difficult to
find back here the concentrical rings. The parietes of the median
chambers are always thick; there was no vestige of a primary
central lamella. Very numerous pori run vertically or obliquely, even
horizontally, from the median chambers to the lateral ones.
Vertical section. Vhere is but one stratum of median chambers,
the height of the ventricles is 354, the thickness of the horizontal
parietes 104. It is very distinetly to be seen how the skeleton-
columns begin only at some distance from the median plane, and
become gradually thicker towards the periphery. On either side of
the median chambers are only 11 strata of lateral chambers.
O. (Lepidocyclina) sumatrensis Brady.
This form is by far the most numerous at the Sungei Blakin. It
can very easily be distinguished from all other forms of the same
place; with O. sumatrensis, which has been minutely described
especially by Newron and Hortanp (Le.) it shows only slight
differences, which are not sufficient to make a new species of it.
The disk has never or scarcely ever warts at the surface, it is
very. thick (¢2—4,h2—2,7mm.) and sometimes even cylindric.
In the middle, one can follow a thin wedge often ending in flaps.
Horizontal section. This form is megalospheric; the embryonal
chamber is partly surrounded by the second chamber, just as with
© polygona and the little Orbitoides of Timor described by Martin (L.c.).
The outer-parietes of these two chambers is 33 uw thick; the separating
parietes between the two chambers only 10. The maximal diameter
of the embryonal chamber, is 190 7, that of the second chamber
310 u. The median chambers are more rhombus-shaped than spatulate,
situated in rather regular concentric rings, often lengthened in a
tangential direction. Their diameter is tang. 90, rad. 60—70u. The
median lamella is indistinct. The number of concentric rings is 30—50.
The shape of the lateral chambers is not so irregular as witb the
greater part of Orbitoides; they are also placed in rather regularly
concentric rings, which is likewise mentioned by Newton and
HoLianp (l.c.) about O. sumatrensis.
Vertical section. There is only one stratum of median chambers
and on either side of these 15 strata of lateral chambers. Though
at the surface no warts can be observed, it appears that there exists
doubtlessly in the interior a firm interjacent skeleton. The height of
the lateral chambers is 70, the thickness of the horizontal parietes
is 30 u.
( 1435 )
Subgenus novum Lepidosemetyclina.
Besides the Orbitoides described I found in the marl of the Sungei
Blakin still numerous Forminifera, which offer in several respects
great aftinity with Lepidocyclina. With those too a system of median
chambers exists, which in general have on the horizontal section a
spatulate shape, and develop themselves round a few large embryonal
chambers; with those too on either side of these median chambers
there are lateral ventricles, of an irregular shape, and between these
a supporting skeleton is found, ending at the surface in numerous
warts. In one respect however these forms show great differences
with Lepidocyclina: the median chambers namely do not lie in
concentric rings, but only in half- or quarter-cireles, in which the
embryonal chambers are lying at the periphery, in the central point
of the circle-sector. Consequently a new subgenus was introduced
for these forms: Lepidosemicyeclina.
Lepidosemicyclina thecideaeformis n. sp.
At the Sungei Blakin occurs only one species of this subgenus having
usually the shape of a cirele-sector of somewhat less than 180°,
and being a little thickened in the central point of the cirele, so
that the little shells make us think of Brachiopod Thecidea. One
side of the shell is often more convex than the other, the latter can
even be concave, so that the horizontal median plane is no longera
pure symmetrical plane. At the surface there is no vestige of lateral
or median chambers; the whole disk is covered with little densely
accumulated warts. There is some variety in the general shape,
because now the tangential, now the radial diameter is the larger,
(2—4 mM.) Sometimes the shell is slightly bent, in most cases however
quite flat.
Horizontal section. In a good section one sees distinctly the large
embryonal chamber, which lies a little beside the central point of
the cirele. It is large and round, and its parietes are thick (d. 160
thickness of the parietes 20 mw). With this embryonal chamber is
connected a still larger chamber, which lies at the extremity of the
shell, i.e. in the central point of the circles and partly surrounds
the embryonal chamber. Its peripheric parietis is still thicker than
that of the embryonal chamber (80 uw); the borderparietis is only
15 uw thick. Two more large chambers, lying more to the centre,
are connected with this second parietis; these three ventricles sur-
round the embryonal chamber in an indistinet spiral. The following
( 1136 )
chambers are already rhombus-shaped. A primary lamella can never
be distinguished at the parietes. Radial diameter of the peripheric
chambers 100 w tangential 90 «@. At thicker spots in the preparations
one sees very distinctly the wide vertical pori going to the lateral
chambers.
Vertical section. There is only one stratum of median chambers.
-In- vertical section this stratum is rather shghtly strung at the
extremities of the chambers. On either side of it are 5—6 strata of
lateral chambers, which are very flat and placed on each other some-
what in the way of scales. The thickness of the fossil is 0.8 mm.
Besides the Foraminifera mentioned I found in the marl of the
Sungei Blakin: Operculina spec., Amphistegina spec. ? Cycloclypeus
spec., and other Foraminifera, which I could not determine.
The third place where numerous Orbitoides could be gathered,
hes on the upper-course of the Sungei Mentawir in strata that are
certainly younger than those on the Sungei Blakin and that most
likely, towards the top gradually pass into the pliocene strata, very
rich in coal, which occur everywhere in the lower part of the Balik
Papan Bay.
O (Lepidocyclina) sumatrensis Brady, var. minor nov. var.
Most numerous is here again a very small Orbitoid agreeing in
nearly every respect with O. sumatrensis of the Sungei Blakin. The
principal difference consists in the fact that the sort on the Se. Men-
tawir is considerably smaller (¢ 1'/,—2, h 1, 2—8'/, m.m.) This
cannot be accidental, because we should have gathered from this
place only the smallest varieties: the material gathered in both places
being much too large. For the further description we ean refer
almost entirely to O. sumatrensis. Only no or hardly any skeleton-
columns occur with the form of the Sungei Mentawir, which would
indeed be astonishing with so small a form which by its globosity
possesses already a natural maximal solidity.
O. (Lepidocyclina) neodispansa Jones and Chapham, var.
m mor, nov. var.
I can dispose of about 20 specimens of this form tallying very
well with one another. In general these have again great resem-
blance to O. neodispansa. The disk is gradually thiekened towards
the middle and a number of comparatively large warts (max. 20
( 1137 )
indicate the superficial end of the skeleton-columns. They are
however smaller than O. neodispansa: d1*/,—3, 4 = 1—1'/, mm. °
Horizontal section. The embryonal chamber is large and has thick
parietes (/ max. 270, thickness of the parietes 20 w). The chambers
round it are half-cireular, and further towards the periphery pretty
well rounded hexagonal, but always irregular. It is very typical
that the median chambers at the periphery are not placed in con-
centric circles, but in the circumference of concentric hexagons, the
sides of which are somewhat concave to the outside. Horizontal pori
between the median chambers are not visible, but very many verti-
eal pori can be observed. The lateral chambers are irregularly
limited and have a wide lumen. They are united together by many
almost horizontal pori. The diameter of the median chambers ,is
45 —50 je; the thickness of the parietes 15 w.
Too little is known of the interior structure of O. neodispansa to
enable us to decide whether the described form agrees in every
respect with this sort; the resemblance in outward characteristics
however is so great that I have not hesitated to describe these Le-
pidocyclines of the Sungei Mentawir as a variety of O. neodispansa.
O. (Lepidocyclina) glabran sp.
Ultimately about 15 specimens of a somewhat larger Lepidoey-
clina were collected at this place, characterized by the indistinctness
or even the absence of superficial warts. by its form it has the
greatest resemblance to O. neodispansa (d@ 2-5, 4 1-2 mm.), but the
absence of warts forbids us to class it with this form.
Horizontal section. Likewise by its micros-
copic structure this sort isobviously separated
from those hitherto deseribed. Most likely
the embryonal chamber is large, the first
peripheric median chambers are irregularly
roundish ; towards the outside however the
chambers become soon spatulate and show
a peculiar typical central lamella which has
the same shape as that of O. flexuosa, but
is much thicker (fig. 4). Perhaps there are
in this primary lamella very fine channels.
Rad. diam. of the median chambers 45, tang. 35 u.
Fig. 4.
Lepidosemicyclina polymorpha n. sp.
In the younger strata of the Sungei Mentawir we meet with a form
75
Proceedings Royal Acad. Amsterdam. Vol. XIII.
(1188 )
of Lepidosemicyliua, corresponding in structure entirely to. the older
form of the Sungei Blakin, so that we can refer to the latter. Exter-
nally the young form differs greatly from the primitive form, espe-
cially by its great variability. Some forms are found that ean hardly
been distinguished from L. thecideaecformis, other specimens are
strongly plaited, scalloped at the peripherical edge, are considerably
protracted in a radial direction and have even a quite irregular shape.
There are some features that point very vaguely to the fact that
thecideaeformis was able to creep, whilst lL. polymorpha had become
fastened. Whilst namely the other Orbitoids ave constructed radially,
which with great probability points to a floating way of living
(plankton) L. thecideaeformis has not only become bilaterally sym-
metric in a vertical direction, but has also obtained an upper- anda
lower-edge (difference in convexity) and has consequently adopted the
symmetry we are accustomed to find in creeping animals. Hereto
comes however that the younger form shows so great a variability
and such irregular forms as we are only accustomed to see of animals
that are fastened (Ostrea).
Besides the Orbitoids described we find in the marl of the Men-
fawir still Amphistegina.
In a few words we shall still discuss rocks of other finding-
places containing only generically determinable fossils.
As old as the clay-marl on the Sungei Pamaluan. is a limestone,
found on rather a large scale in the delta of the mentioned river.
Herein the vertical section of a little Orbitoid, a Globigerina and
perhaps also Amphistegina was found. The limestone is very compact,
becomes scarcely transparent under the microscope and contains
occasionally grains of pyrite.
Younger than the Pamaluan-marl, but perhaps older than the Blakin-
marl is a marly sandstone, found on the Sungei Binuwane.
Under the microscope the marl appears to consist of polygonal
grains of quartz united together by a cement rich in Fe- and Ca.
It contains Amphistegina, a single Alveolina 5 mm. long, a few
Orbitoides and a large spiral-shapedly constructed Formanifere (not
Spiroclypus) entirely unknown to me.
A marl that is found on the 5. E. coast of Pulu Balang and of
Which a specimen contains a large enclosure of resin is entirely filled
with Foraminifera, among which: Miliola, a very small Alveolina,
Globigerina, Amphistegina, a small Orbitoid and others can be
recognized. The marl contains many polygonal grains of quartz,
whilst the fossils often enclose grains of pyrite.
Consequently the Orbitoides deseribed above may be classed into
L. RUTTEN. ‘On orbitoides in the neighbourhood of the Balik-Papan Bass
bE
(East-coast of Borneo)
Shetch-map ot the
BALIK PAPAN BAAI
Seale 1,250,000
a Sepahke
urea
Proceedings Ryoal Acad. Amsterdam. Vol XIII.
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( 1139 )
three different divisions of the Tertiary on the Balik Papan Bay :
Mentawir strata L. sumatrensis var. minor, L. neodispansa
var. minor, L. glabra, Lepidosemicyclina
polymorpha.
Pulu Balang-strata L. acuta, L. flexuosa, L. sumatrensis,
(Sungei Blakin) Lepidosemicyclina thecideaeformis.
Pamaluan-strata L. aff. formosa, L.? neodispansa.
The stratigraphical succession thus obtained does not entirely agree
with the one given by H. Dovuvinié. It is true that with us in the
oldest strata occur simple forms of the type L. formosa, but beside
these immediately forms of the type O. neodispansa are found, which
according to DovuvitLé must be much younger. On the Sungei
Blakin occur then beside each other forms with strongly and feebly
pronounced skeleton-columns (QO. flexuosa) forms of the type of L.
sumatrensis, and forms with one single, large, central wart, which
according to Dovvitt¥ should occur in separate horizons. The same
holds for the youngest strata, the Mentawir-strata.
It is however remarkable, that in the oldest level the simplest
forms occur, that in the middle level the number of species is greatest,
and that in the youngest level, which cannot be much older than the
dying-out-period of the genus, two minor forms occur, whilst of a
third species very peculiar variations are found.
Zoology. — “OVbservations on the Genus Spirastrella’. By Prof. G.
C. J. VosMarr.
(Communicated in the meeting of March 25, 1911).
Oscar Scumipr established (1868) the genus Spcrastrella tor a “new
species” of Siliceous Sponge, the chief character of which was said
to be that it possessed an “eigenthiimliche Art von strahligen Kiesel-
kérperchen, deren Strahlen spiralig gestellt sind.” We now know
that that sort of spicules is by no means of rare occurrence, and
that it does not represent a special form of polyaxons, but of mo-
naxons; such spicules are now called spinispirae. In addition to these
spicula the skeleton of Spirastrella is composed of tylostyles or also
of styles. Since Scumupr described his Spirastrella cunctatrix, various
authors have mentioned numerous “species”; all in all about 44.
But of these, ten are to be cancelled at once, either because they do
not belong to our genus at all, or because they are quite inadequa-
tely described, so that they are not recognisable.
75*
( 1140 )
In the rich collection of the Siboga Expedition 1 found about a
hundred specimens of Siliceous Sponges, which I believe belong
to the genus Spirastrella. 1 examined them as carefully as cireum-
stances allowed; moreover I studied about forty specimens from
other localities, chiefly types of previous authors and for the greater
part deposited in the British Museum. The result of this research is
that I am convinced that we have to do with an uncommonly variable
species; 82 of the 384 “species”, deseribed by previous authors,
and all the specimens of the Siboga collection belong to one single
species, which, according to the rules of priority, has to be called
Spirastrella purpurea (Link.) Rdl.
If we look at the specimens macroscopically, we at once see differences
so great, that any one would expect to have to distinguish a number
of “species”. Sometimes they appear as thin enerustations on old pieces
of coral, coralline algae etc., sometimes as thicker cakes with warty
elevations. Another time they are club-shaped, or cylindrical with finger-
shaped terminations, or cones, or pyramids. Others again have an
irregularly spherical shape and form massive lumps. The colour is
pale or bright yellowish, brown, grey; sometimes bright carmine red.
Among the encrustiag forms some are no more than 1 or 2 mm. thick;
on the other hand we find massive specimens of 12 by 18 em. ; nay
BowrRBANK mentions one, which reached a height of almost 2.5 me-
ters. The surface is even, or provided with warty or digitiform eleva-
tions; smooth or hispid.
However, if we more carefully examine the specimens and then
try to classify them into groups, we soon come to difficulties
and we find e.g. specimens which might be placed in one group
as well as in another. Thus we find that some crusts are on the
whole very thin, but nevertheless show here and there thicker regions;
in faet we see the thin crusts gradually pass into thick cakes, or into
specimens with warts, tubercles or finger-like processes. In some cases
these processes have all about the same size; in other cases there
is one main process with a number of smaller ones around it,
gradually leading in this way to pyramidal cones with or without
a few secondary processes at the base. Again in other cases the
cylindrical processes are so long and numerous that they form the
most characteristic feature of the sponge. Moreover, we may observe
another phenomenon, viz. that neighbouring processes coalesce ; in fact
we see e.g. clubshaped specimens pass into spherical, massive forms.
From this state of things results the impossibility of making ‘‘spe-
cies” on account of the external appearance ; the extremes are united
by all possible connecting links.
( 1141 )
How is it now with the internal structure ? The answer to this
question is that we find here similarly great differences, but likewise
all gradually passing into each other. This is true as well with re-
gard to the canal system, as to the structure of the parenchyma and
the skeleton, even with respect to the elements of the latter, viz.
the spicules. I do not wish to discuss now these points in extenso ;
I will give a couple of examples, as I did regarding the external
habitus.
It is characteristic for Spirastrella that the skeleton consists of
longitudinal bundles of spicules, chiefly tylostyles, branching towards
the periphery; between these bundles, but more especially forming
a superficial crust, we find the well known spinispirae. It is a remarkable
fact, that this represents the complete skeleton; under certain
circumstances, however, the spinispirae may become very scanty and
may even disappear altogether. In the latter case the character from
which the genus has received its name, is absent'). In the papers
of almost every spongiologist we find that species are distinguished
e. g. on account of the size of the spicules. In our case the size of
the tylostyli shows considerable differences. The maximal length
I found in my specimens to oscillate between 280 and 800 «., whereas
the maximal diameter varies between 5 and 30 u. Nevertheless, the
extremes are united by all possible intermediate stages; no limits
can be drawn for specific distinction. There are, however, certain
sizes which prevail. The maximal length is in about 33 °/, cases
550 @ and more, but less than 600 a; in about 75°/, cases 500 4
and more, but less than 650 «. Cases of less than 350 mu or more
than 700 mw are rare. And so I found in 20°/, cases the maximal
diameter of the tylostyli 16 mw and more, but less than 22 u. I seldom
found it less than 6 w or more than 24 wu.
Sull more striking are the differences of the spirispirae. We have
already seen that these characteristic spicules sometimes oceur in great
abundance, at another time are exceedingly scanty. Thus I found in
some specimens that one microscopical preparation of spicules, isolated
by means of hydrochloric or nitric acid, contained a couple of spini-
Spirae, whereas another slide of the very same specimen contained
not a single one. Denny found in his Siberites inconstans var. globosa
and var. maeandrina no spinispirae. | was able to examine Denpy’s
types in the British Museum and did find them. Such facts are by
1) This phenomenon is by no means seldom in the animal kingdom. It may
perhaps be compared with the absence of a chorda in certain Chordata. The more
so as I have reason to believe that the said spicules are present in larval or
young stages, but afterwards disappear.
( 1142 )
no means standing alone; they are examples of very numerous cases.
This implies, however, that, if in certain specimens, externally cor-
responding, in one we find spinispirae, in another not, we have not
the slightest right to establish new species or genera on account of
the presence or absence of spinispirae. It is beyond doubt that
Denpy’s sponge is not a Suberites but a Spirastrella.
Now we find spinispirae of every description '). In many speci-
mens of Spirastrella purpurea we find in addition to minute (but
full grown) spinispirae of say 8—10 « length, large robust ones of
about 12 u in diameter by a length of 75 uw. In other specimens
such giants are missed altogether. At the beginning of my investi-
gations I believed I should be able to find specitic characters on this
account. But I was forced to give up this view; for those large
spinispirae sometimes measured a good deal less than stated above,
or they possessed the Jength but noi the diameter. In this respect
again we find gradnal transitions. These facts and the fact, that robust
spinispirae are sometimes abundant, sometimes scarce or absent,
teach us that we cannot yet establish species on account of the
presence or absence of large spinispirae in addition to the minute
ones. We have as little success if we try to distinguish species by
certain microscopical details. LenpenreLp described a “new species”
because of the fact that the spines of the spinispirae did not terminate
in a sharp point, but showed a curious very minute denticulation.
I found, however, on carefully studying the spicules with oil-immersion,
that the ‘“Efflorescenz-artiges Ausselen” appears in numerous specimens
of the most various external appearance.
Summa summarum: we have to face the dilemma either of con-
sidering all the examined specimens as one species, or to establishing
almost as many species as we examine specimens. | for my part do
not hesitate which way to go. At present, at all events we still know
very little about the comparative anatomy of Sponges and hardly
anything about their comparative embryology. And yet these lowest
Metazoa deserve to be studied carefully. Although they throw but
little light on phylogenetic questions, and perhaps will never do so
because they are an aberrant branch of Metazoa, in other respects |
an convinced the Parazoa are certainly of general importance. For
instance on accopnt of their tissues. But the field of Spongiology is
unexplored except by a few specialists. Not quite without reason, for
there are many traps.
1) Since it is impossible, for the moment, to make out whether we have to do
with one or with more sorts of spicules, J consider them for convenience’ sake as
one kind.
( 1143 )
If we can accept but one species of Spirastrel/a, the question
arises whether perhaps certain groups of specimens point to a closer
relationship to each other? Is it possible to distinguish groups according
to the depth or to certain properties of the bottom on which they
are found? The first question can be answered in a positive sense,
the others not yet. Indeed I believe that about seven such groups may
be distinguished, although by no means sharply, as they are all
intimately connected. But if we unite a certain number of specimens
which seem to be nearly related to each other, into groups and try
to bring them into connection with their conditions of life, we soon
find that hardly any conclusion can be drawn. For there are speci-
mens from the same locality which do not belong to the same
group; consequently we cannot speak of so-called local varieties.
The general structure of Spirastrella purpurea is, in spite of
great differences, still fundamentally the same for various specimens.
I will give a sketch of one form, viz. of a specimen corresponding
to Drnpy’s Suherites inconstans var. digitata. A longitudinal section
through one of the long finger-shaped processes shows us a central,
more or less cylindrical cavity, generally opening at the top of the
process. Such wide central canals are often met with in Porifera.
The terminal opening is usually called “osculum” and the canal is
considered to be of an excurrent nature. Indeed it is observed
in many living Sponges that a current of water flows out from
the “osculum”, the water entering through numerous little apertures
on the sponge surface. Microscopical examination of such Sponges
has shown that the latter apertures communicate with “flagellated
chambers”. These chambers on the other side communicate again
with a system of cavities, which open into the central canal, mentioned
above. Now we know that the shape of the flagellated chambers and
the position of the choanocytes determine the direction of the water-
current. Consequently we can conclude from the shape of the
chamber, which of the communicating cavities is exeurrent, and
which is incurrent. The whole canalsystem can thus be reconstructed
by studying series of sections. This has been done for several Sponges,
but not as yet for the majority. Since it was found in certain cases,
that the large central canal belonged to the exeurrent system, the
conclusion was drawn per analogiam for other cases, that the said
canal is excurrent.
However, in Spirastrella purpurea certain features seemed an
obstacle to considering the central canal as a ‘cloaca’. True, in
several specimens the canal opened with a comparatively wide
mouth, but in others the aperture is rather small. Moreover the canal
( 1144 )
is in most cases narrower at the top than lower down, and in many
cases it is clearly seen, that the wide central canal towards the
top of the process branches into a number of much narrower
ones. Finally I found that the wall of the canal is not smooth, but
shows several transverse. rugae. Such a canal, according to the
theory of Prkrinartine and myself, would be very littke adapted to
act as a cloaca. In view of all this I thought it necessary to recon-
struct the canal system by means of series of sections. The result
has been, that I found the positively excurrent canals not to com-
municate with the central cavity, but exactly the contrary: the
incurrent canals communicate with if. Consequently, the central
canal is not a cloaca but an incurrent reservoir. Numerous minute
apertures (stomata) lead into a system of canals, which open in the
central cavity, which also may communicate directly with the sur-
rounding medium by means of a comparatively wide opening at
the top of a process. From this reservoir canals start and enter,
ramifying, the parenchyma; they ultimately communicate with the
flagellated chambers or mastichorions as I have called them. As the
canal system is eurypulous, the mastichorions open with a wide
apopyle in the excurrent lacunae or canals, which finally likewise
open at the sponge surface with small apertures, procts.
There is still another interesting feature in the canal system of
Spirastrella purpurea. Jt is generally accepted that the principium
movens for the watercurrent is to be songht for exclusively in the
flagella of the choanocytes. In our sponge a second factor appears :
in the wall of the larger canals, more especially of the central
canal, numerous undoubtful musele cells occur; they are situated in
concentrical and in radial bundles. In the rugae we find the former
in maximal dilatation. If on the other hand the concentrie muscle
cells contract the ragae are stretched out to a kind of membraneous
diaphragms with the result that the lumen of the canal becomes
considerably narrower. In some specimens this is in fact the case.
Suppose that the terminal aperture has first closed, water must
forcibly be pressed into the canals whieh lead to the inner parts
and in this way the current-producing power of the flagella helped.
In this connection it is worth while to remark that the total quantity
of mastichorions is Comparatively small.
The parenchyma is almost entirely composed of a remarkable
tissue to which | more than once have drawn attention and which
can best be compared with lymphoid connective tissue. It consists
of flat cells with delicate membraneous processes, forming together
a sort of syncytium. At least I could not distinguish cell limits. In
( 41145 )
this way a reticulum is formed, the meshes of which are very
different in size. In addition to these cells, fibres occur beyond doubt;
perhaps also a kind of elastic fibres. For the rest we find cells of
various description: amoebocytes, thesocytes, fusiform cells ete. The
canals are lined with flat cells, which have exactly the character of
the first mentioned cells; they may be considered as endothelium.
The skeleton is mainly formed by bundles of tylostyles. In
encrusting specimens these bundles stand vertically on the substratum;
they ramify generally towards the periphery and at any rate terminate
in brushes. The spicules of the latter are usually smaller than the
tylostyles of the main bundles. In massive specimens or those with
finger-shaped processes long longitudinal bundles run through the
parenchyma, here and there ramifying, occasionally anastomosing.
These main bundles give off smaller branches towards the periphery;
these as well as the main bundles terminate in more or less pro-
jecting brushes. Hence the sponge surface is now rather hispid, then
smooth. On the whole we can say that the number of superficial
tylostyles is in reverse ratio to the number of spinispirae. If the
latter are abundant they form a ‘dermal’ crust. If in addition to
minute spinispirae robust ones occur, this crust is composed of one
or two distal layers of the former and 2—5 proximal layers of
the latter.
In many specimens with well developed longitudinal bundles,
strings of darkly stained cells are seen at once in every preparation.
These cells are more or less fusiform, possess a large nucleus and
a large “nucleolus”. They are found in close connection with the
bundles of tylostyles. Most probably these cells are fibroblasts;
they are the cells which form the connective tissue fibres, which
strengthen the bundles of tylostyles by binding together the spicules.
This tissue [ have called periapt'); herein occur, in addition to
fibres, fusiform cells etc. These fibroblasts which thus give rise to the
fibres, are not always situated in such conspicuous strings; but they
may be found everywhere, where fibres are to be formed or are
normally present.
The occurrence of spinispirae, the arrangement of the canal system,
the whole anatomical structure of Sprrastrella, all suggests a close
relationship to the so-called Boring Sponges, belonging to the genus
Clona. The two genera are, however, distinguished from each other by
the fact that Clona perforates calcareous matter (shells, corals,
coralline algae ete.), whereas Spirastrella does not bore. Several speci-
1) Proceed. Kon. Akad. Wetensch. 1905, p. 23.
( 1146")
mens of the Siboga collection are encrusting and sections of decalcified
specimens simulate a boring sponge; in reality Spirastrella does not
itself perforate, but easily fills up holes and slits of a calcareous
substratum, destroyed by other organisms. As such I found e.g.
Thoosa and certain Fungi *).
Physiology. “The action of strychnine on the Central Nervous
System. The segmental, strictly localized strychnine-intoaication
of the dorsal spinal mechanisms: a contribution to the derma-
tomery of the hind leg in dogs.” By Dr. J. G. Dussur pre
BareNNE. (Communicated by Prof. C. Wixkunr).
(Communicated in the meeting of February 25, 1911).
In a former communication®) [| endeavoured to prove that the
theory, as if strychnine-tetani may have their origin in an intoxication
by this alkaloid of the dorsal, co-ordinatory spinal mechanisms, is to
all probability an erroneous one.
The application of the poison exclusively on the dorsal surface of
the medulla, never gives rise to tefani as its consequence, but aiways
to another complex of symptoms, which was described by me as the
Syndrome of strychnine-intoxication of the dorsal spinal mechanisms :
1. Subjective disturbances of sensibility, most probably presenting
a paraesthetical character.
(Finding their expression in the frog by “Abwischbewegungen”, in
the dog by licking and biting the skin).
2. Hyper-reflectory actions.
3. Spontaneous muscle-shocks, viz. arising without any exterior
cause being observable, but still for the greater part proceeding ina
reflectory manner.
Already with the first experiments it became evident that, whilst
this complex of symptoms in itself is constant and characteristic, the
skin-field in which these disturbances of sensibility (both subjective
and objective ones) occur, is variable as to place and extension,
1) Extensive descriptions accompanied by illustrations, will appear im the Results
of the “Siboga-Expedilie’, which is in the press.
2) Dusser DE BARENNE, Die Strychnin-wirkung auf das Zentralnervensystem. Il.
Folia neurobiologica. Band V, Heft 1, 1911. Provisory communication iz Zertralblatt
f. Physiologie. Band XXIV. N®. 18, 1910.
( 41147 )
according to the different parts of the spinal cord on which the
strychnine is applied.
If this poison is put on the caudal spinal segments, the symptoms
are shown in the posterior portion of the body.
If I poisoned the dorsal mechanisms of the right half of the
intumescentia lumbalis, the syndrome manifested itself exclusively
in the right hind-leg.
In another case again the poison was applied on the dorsal surface
of some of the caudal segments of the thoracal part of the medulla,
after which the symptoms, described above, were manifested in a
zone encircling the body like a band and passing over the most
caudal ribs.
From these facts it becomes evident that the syndrome may be
localized. It is even possible, if one after another the dorsal surfaces
of single spinal segments are poisoned, to obtain a series of skin-fields,
within which the syndrome is manifested, differing among them
as to form, situation, and extension.
In this manner in a series of experiments, from 7h. XIII to S.1
included, I have poisoned successively the dorsal mechanisms of
every single spinal segment and by so doing I obtained a number
of skin-tields in which the syndrome (— paraesthesia concluded by the
biting and licking of the skin-field, hyper-reflexion, concluded by
violent reactions if the skinfield was touched) was manifested ;
those skinfields were placed in regular succession on the hindleg of the
dog, their shape, situation, and extension being characteristic for each
single zone. I will call these skinfields strychnine segmental zones.
As an instance of the way in which I proceeded in this series of
experiments, as regards the method of the strychnine application, as
well as the examination of the sensibility and the defining of these
strychnine segmental zones, the protocol may follow here of one of
my experiments on the caudal thoracal spinal cord; the more so
because from the adjoined figures (fig. I—IV), demonstrating the results
obtained in two cases of defining the boundary of the strychnine
seemental zone of 7h. X, it becomes clearly obvious how much for
one and the same segment the zones resemble one another as to
shape, situation, and extension.
I have chosen this experiment also, because the strychnine zones for
the trunk segments are very simple as to shape, contrary to those
situated on the extremity, and therefore showing with greater evidence
their mutual resemblance.
(1148 )
Protocol I.
June 6%, 710. Str. Doge XVIII. “Dackel”.
The caudal portion of the thoracal spinal cord is uncovered and
the dura-mater cleft over 7/4. 1X, X and XI, the liquor cerebrospinalis
that has flown out, is sucked up by a bit of wadding. Then
strychnin is applied in the following manner :
A small piece of wadding, long + 8 mm., wound around the
branches of a thin pair of nippers, is immersed in a 1°/, solution of
sulfate of strychnine dyed with methylene-blue, and then pressed out.
With this piece of wadding the dorsal surface of the segment of
Th. X, at the entrance-point of the right posterior nerve-root, is
repeatedly bathed with the utmost carefulness.
After each contact with the stryclnine wadding the superfluous
poison that has eventually been appled, is sucked up by another,
clean and moist piece of wadding.
A few seconds after the repeated contact of the poison with the
spinal cord at this spot, the dog that meanwhile has nearly awakened
from the narcosis, begins to lick the skin of the right half of the
trunk over a region, extending like a band of moderate breadth from
the mid-dorsal to the mid-ventral line, passing over the most caudal ribs.
~The dog itself, with its moist tongue, marks pretty clearly the
boundary of this zone. The objective part of the syndrome is likewise
extant and may be easily aroused from out the same skin-zone. The
hyper-retlectory symptoms are: 1. wrinkling of the skin, 2. curving
of the vertebral column, the concavity turned to the right, 3. with
intervals scratching movements of the right hind-leg, resembling
closely those of the well-known SHERRINGTON’s ‘“seratch-reflex’’.
In order to obtain an objective definition of the extension of the
strychnine-segmental-zone, | touch very gently the skin of the animal
in the neighbourhood of the region within which the syndrome is
manifested, either with one of my finger-tips, or with the point
of a curved, shut pair of nippers.
Continually vepeating this gentle, mechanical irritation, [gradually
approach that region, and as soon as I have passed its boundary,
the hyper-reflectory symptoms described above are aroused or become
much more intense, whilst in most cases‘) the animal shows at the
') I say “in most cases”, because the intensily of the subjective part of the
syndrome presents great variations in different cases, partly dependent on “tempe-
rament and character” of the animal, whilst for another part they may perhaps
be ascribed to its more or less complele awakening from the narcosis.
( 1149 )
same time by howling and biting that the subjective symptoms are
likewise aroused or their intensity increased.
By means of a skin-pencil the boundary obtained in this manner
is marked on the skin and so the zone defined. After this the animal
is killed, and either the posterior part of the body is photographed,
or the zone is exactly designed on a model in plaster of the extremity.
Firstly however on the skin resp. the plastermodel, the different
fixed points and lines are indicated, viz. the last rib, the crista ilei,
the trochanter major, tuber ischil, epicondylus femoris lateralis and
medialis, patella, tuberositas tibiae and malleolus medialis and lateralis.
After this the autopsy is made, and in so doing it is accurately
verified on which segment the poison was applied whilst an eventual
anomaly of the vertebral column is also mentioned in the protocol.
Fig. Ul. Th. X. Fig. IV. Th. X.
My material, as far as regards these researches, consists in 29
experiments, distributed over the different segments in the following way :
On the segment of
Th. X strychnine was applied 3 « (Str. dog XVIII, XIX, XX)
Th. XII x - r 1 x (Str. dog XLIV)
G1 - f a, 1 x (Str. dog XLV)
/ ej All * 3X (Str. dog XII, XXV Z., XLVI)
sil ¥ - se 3X (Str. dog XXI, XXIX, XLVII)
LEN: - Be me 4x (Str. dog XIV, XXV R., XLVIII,
XLIX)
Mie NG = 3 . 3 xX (Str. dog XV, XXXI, L)
ENA + so s 3 x (Str. dog XVI, LI, LI])
NG ap 3 6 x (Str. dog XVII, XXII, XXII,
XX VI, LIIE, LIV)
‘Spal ms gi ie 2x (Str. dog XXIV, LV).
( 1150.)
Some months ago, the researches of Winkiur and vAN Riunperk
were published,') a series of experiments in which, by means of
the SHERRINGTON isolation method they demonstrated on a large material,
comprising 40. objects, the dermatomery of the hindleg in dogs.
When that work was published, the series of my experiments was
nearly completed and I could state an indeed striking accordance
between the results obtained by those investigators as to shape,
situation and extension of the dermatomata they found, and my
strychnine segmental zones defined by means of this strychnine method,
an accordance and a resemblance that in some cases grew nearly
to identity, as will be shown here after.
I intend in the following pages to give the results obtained hy me
in that respect, comparing everywhere my strychnine segmental zones
with the proportions found by Winker and van Runperk for their
dermatomata. f
The theoretical speculations and consequences resulting from the
facts that will be told, shall not find any place in this communication.
Th. XU. The strychnine zone of this segment, like those of the
trunk segments, presents still a very simple shape, its various properties
therefore are clearly enough demonstrated by the Fig. V and VI
without adding anything.
Fig. V. Th. XII. Fig. VI. Th. XIll.
1) WinkbER and vaAN RiJNBERK. “Experimental researches on the segmental
innervation of the skin in dogs’. VI and VIL communication. These Proceedings
of Juny and September 1910.
—
( 7152 )
L. 1. What strikes us first of all, is the fact that this strychnine-
segmental zone obviously lies more caudalward on the body than the
preceding one. To ascertain this, we have only to compare the caudal
boundaries of these two zones in their relation to the crista iliaca,
as shown resp. in Fig. V and in Fig. VII. Practically this zone is
not yet lying on the skin of the extremity, though we may perceive
the neighbourhood of this latter by the small linguiform projection
presented by this zone in the skinfold of the groin. See Fig. VIL.
Winker and van Rixperk found analogous proportions for their
dermatoma of /. 1.
Rio Ville an! Kigs VAlls ae
L.11 is the first segment, the strychnine-zone of which lies on
the skin of the extremity. Compared with the zone of 4.1 it is
situated more candalward, which is shown among others by the fact
that the erista ilei now lies partly within this skin-field.
This strychnine-segmental zone extends very far on the lateral
surface of the extremity, whilst it covers likewise a great part of
its medial surface.
The most distal point of this zone on the extremity is situated at
about 2'/, em. from the upper margin of the patella, as is shown
in Fig. IX and X. In all my cases the situation of this distal boundary
was the same, I also always found the fixed points of the knee-
joint lying outside the zone.
The statements of Winkuer and van RuisNpurk concerning the
dermatoma of /u, are perfectly identical with what I found about
this zone. At the mid-ventral line the strychnine-segmental-zone is
( 4152 )
rather small and covers the skin of the root of the penis, without
passing on the serotum.
In female animals the caudal boundary of the zone is situated
+ 2'/, ¢.m. ecranially from the foot of the Mons veneris.
ake ©. Gay Dn 0 Fig. X. Z. Il.
ZL. wt. Contrasting with the nearly for all cases constant situation
of the boundaries of the strychnine-segmental zone of L. nm, as e.g.
relative to the trochanter and to the fixed points of the knee-joint,
we remark in the zone of “4. mi that, though the form remains
nearly the same, the situation of the boundaries in different cases
is rather variable.
In Str. dog XLVI e.g. I found that the caudal boundary runs
Fig XI. LZ. il. rig. XII. L. LI.
( 1153
about 2 ¢.m. cranially from the throchanter along this latter, whilst
in Str. dog XXIX this boundary lies somewhat caudally from
this point on the lateral surface of the extremity. WINKLER and VAN
Runperk likewise stated analogous variations for their dermatomata.
At the mid-ventral line this skin-field extends over the root of the
penis and part of the scrotum.
L. IV. The strychnine zone of this segment presents a strong
likeness to that of the preceeding segment, only it is situated more
caudalward and therefore farther distally on the extremity.
At the mid-dorsal line the cranial boundary is always found caudally
from the crista ilei. On the lateral crural surface the caudal boundary
in most eases runs nearly across the trochanter in the direction of
the knee-joint and passes the crista tibiae + 4 e.m. distalward from
the tuberositas tibiae.
At the mid-ventral line the scrotal skin is covered by this zone.
Fig. XIII. L. IV. Fig. XIV. L. IV.
L.V. It is characteristic for this strychnine-segmental zone that it
has lost all connection as well with the mid-dorsal as with the mid-
ventral line of the body. Winkier and van Runperk likewise found
this to be the case for their dermatoma of 4, V, and for this reason
gave it the name of first “top-dermatoma”’. The zone extends partly
over the lateral, for another and greater part over the medial crural
surface. Its most proximal point is lying on the lateral crural surface
nearly in the middle of the line connecting throchanter and epicondylus
femoris lateralis. From this point the cranial boundary goes distal-
ward, passes on the inner surface of the extremity and thence bends
to the medial crural surface.
76
Proceedings Royal Acad. Amsterdam. Vol. XIIL.
( 1154 )
The candal boundary of this strychnine-segmental zone passes on
the medial surface of the nether-leg between the proximal and the
medial third of the crista tibiae.
On this portion of the extremity this skin-area lies entirely
on the medial side, so that it presents itself here as a narrow tongue,
which for different cases differs in its extending more or less far
distalward. Sometimes it reaches not farther than the malleolus
medialis, in other cases it even joins the sole of the medial toe.
The malleolus medialis either lies in the middle of this narrow
tongue or just on its cranial boundary.
Analogous proportions were found by Witnkupr and van RiuNBurk
for their dermatomata of 1. V.
* * “
Fig. XV. L. V. Fig XVL. LZ. V.
L. Vi. Farther still than the strychnine-segmental-zone of L. V
that of the VI lumbar spinal segment is lying on the medial surface
of the extremity. Only a very small portion of it is still situated on
the lateral surface of the extremity. Whilst the zone of Z. V covers
at the utmost the skin of the medial toe, the strychnine-zone of L. VI
covers the whole of the medial half of the foot, as well on the
palmar as on the dorsal surface. Like Winker and van RUNBERK,
whose data for the dermatoma of ZL. VI are in accordance with
those found by me for the corresponding strychnine-segmental zone,
stated for the dermatoma, we may therefore say that the strychnine-
zone of L. VI appears wound spirally around the netherlee and the
foot. In none of my cases I found this zone connected with the
midventral or the mid-dorsal line, as little as the authors quoted
above, found such a connection for their dermatoma of ZZ. VI.
( 1155 )
L. Vil. The strychnine-zone of this segment likewise lies distally
on the extremity, although it extends already much farther proximal-
Fig. XVIL L. Vi. Fig. XVIII. L. VL
ward on the lateral surface. This zone presents a typical long-
stretched shape, and its situation and extension too are in all cases
characteristic.
As regards its situation, this skin-zone is characterized by the fact,
that it covers the lateral surface of the foot and the netherleg, and
extends over a large portion of the postero-lateral surface.
The extension of this strychnine-segmental-zone is a rather variable
one. Whilst sometimes these zones extend distalward only to the
malleolus lateralis, there may be found others, and such is generally
Fig. XIX. 2D. VII. fig, XX. D F ig, XXI. L. VII.
76*
( 1156 )
tlhe case, covering also. still a portion of the foot, either only the
skin of the lateral toe or the whole of the lateral half of the foot.
Winker and van RuNeserk found identical proportions for their
dermatomata of LZ. VII. As the average size of this strychnine-
segmental-zone I think we may assume that where, both on the
dorsum and on the sole of the foot, the skin of the two lateral
foes is covered by its area.
Fig. XXI reproduces the divers variations in extension of the Z.VII
zone on the foot as found in my experiments.
S. I. According to the statements of Winknrr and vAN RiJNBErk,
the dermatoma of SI is the first caudal marginal dermatoma, i.e.
the first of the caudal dermatomata of the extremity that has recovered
the connection with the mid-dorsal and mid-ventral lines.
The corresponding strychnine-segmental-zone behaves exactly in the
same way.
In as much as this zone extends over the proximal portion of the
extremity, there is accordingly a fundamental difference between it
and the preceding strychnine-segmental-zone. At the distal end of the
extremity however the two zones are nearly identical as to shape and
extension, though it may be taken for granted that generally the
zone of SI is situated somewhat more on the posterior surface than
that of Z. VIL and does not extend as far distalward as this latter.
For, in as much as I was able to state so from my material, the
narrow tongue, protruding from this zone on the nether-leg never
extends farther than unto the tuber caleanei.
WINKLER and vAN RuNBERK, who have isolated in 5 cases the
Fig, XXL SI.
( 1157 )
dermatoma of S.1, stated in one of these‘) (dog 11) that here the
skin-field extended to the lateral toe. In the four remaining cases
the distal boundary of the dermatoma was lying also between fossa
poplitea and tuber calcanei.
The strictly localized application of strychnine on the dorsal surface
of the first sacral segment presents certain difficulties, not only
because this portion of the spinal cord is rather wanting in length,
but also, and this latter factor especially gives rise to obstacles,
because the dorsal surface of this segment is almost entirely covered
by the cauda equina, which is strongly developed in this region of
the spinal cord.
Still much worse those difficulties become in the more caudal
segments of the sacral spinal cord, in these latter therefore there can
be no question of precise localisation, and for this reason I have
closed my series of experiments with the definition of the strychnine-
segmental-zone of SI.
We have now come to a summary of our results.
The first strychnine-segmental-zone lying on the extremity is that
of LI, for this zone is the first covering the greater part of the
skin on the anterior crural surface.
The zones of the segments / III and LIV resemble one another
very closely, and though it cannot be denied that their conformity
presents many individual variations, yet in a general way we may
conclude that the caudal boundaries of these two strychnine-segmental-
zones are nearly identical, and that this common boundary runs along
a line, departing from the mid-dorsal line in the middle of the sacrum,
and goes over tle trochanter in the direction of the epicondylus
femoris medialis.
The zone of the segment of ZL V is the first zone of the posterior
extremity no longer connected with the mid-ventral and the mid-dorsal
lines. WINKLER and vAN RiJNBERK, when stating the same fact for
their dermatoma of LIV, call it therefore the first top-dermatoma,
understanding by this name the dermatomata lying on the apex of the
extremity, this latter considered as a cone with an obtuse top.
The strychnine-segmental-zones of VI and ZL VII have likewise
lost all connection with the mid-dorsal and mid-ventral lines, whilst
that of SI is again in coherence with both. These statements are in
perfect accordance with those given by WINKLER and van RuNBERK
for the corresponding dermatomata, as indeed we have remarked
before. When assuming therefore the terminology of those authors,
1) WinKLER and van RisnBerK, Vith Communication. ].c¢. p. (304) 33.
( 41158 )
we may say that on the hind-lee there ought to be distinguished 3
cranial marginalstrychnine-segmental-zones, viz. those of L1I, 1 U1,
and LIV, 3 apieal strychnine-segmental-zones, viz. those of LV,
LVI, and “4 VU, and at least 1 caudal marginal strychnine-segmental
zone, viz. that of SI.
According to Winkipr and van Rixperk, the dermatomata of SII
and STIL are. still caudal marginal dermatomata of the posterior
extremity, these two being then the last. As we told before, it is
impossible to obtain a strictly localized strychnine-application on these
segments, for which reason I have not determined their corresponding
strychnine-segmental-zones.
When examining Fig. XXII, we may see that the cranial boundary
of the strychnine-segmental-zone of SI leaves the mid-dorsal line at
the centre of the sacrum and passes over the troehanter, directed
towards the epicondylus medialis, changing then its direction some-
what distally from the trochanter and bending to the posterior surface
of the extremity.
For the common caudal boundary of the zones of LUI and LIV
we could state an identical course, at least unto a point somewhat
distally from the trochanter. In this case therefore the strychnine-
segmental-zones of segments not immediately succeeding one another
in the series are bounded by one another.
Winker. and van RusxBerk found wholly identical relations for
their dermatomata, and design therefore this demarcation-line between
skin-fields that originally are not bounded by one another as the
“dorsal axis-line’ (SHERRINGTON) or the ‘dorsal differential boundary”
(Bok) of the extremity.
On the ventral side and the medial surface of the posterior extremity
we find the following relations :
The caudal boundaries of the strychnine-segmental-zones of / I,
LI, and ZIV run along the same line for a large part of their
course; it may even be said nearly that the ventral portions of these
zones entirely cover one another reciprocally.
Although the lack of fixed points on the abdomen and the medial
crural surface (the nipples may on no account be regarded as such)
is a cause why the course of the zonal boundaries cannot be defined
as sharply as on the extremity, yet we make a very near approach
io expressing the genuine relations, when saying that the common
caudal boundary of the ZI, /111and LTV strychnine-zones is formed
by a line departing from the symphysis in the direction of a point,
situated on the medial surface of the extremity nearly in the middle
between epicondylus femoris medialis and fossa poplitea. The caudal
( 1159 )
boundaries of the / IIL and LIV zones even pass over this point
and consequently run together over the whole of the medial crural
surface, whilst the caudal boundary of / II, leaving this line some-
where in its course, diverges thence with the common caudal boundary
of the ZIM and LIV zones.
The cranial boundary of the stryehnine-zone of SI, as is clearly
shown by Fig. XXIII, likewise leaves the mid-ventral line just before
the symphysis, after a short course it bends more candalward in
the direction of the epicondylus femoris medialis, and continues
farther, over the point mentioned above that lies in the middle between
this epicondylus and the fossa poplitea, in the direction of the malleolus
medialis. Evidently here on the medial crural surface too, there isa
demareationline between skinfields that are not originally bounded
by one another.
WiInKLER and vAN Runeerk, in their VIItt communication have
stated an identical course for the demarcation-line between the
dermatomata of 4.U, “4.1, Z.1V and SJ, and by them this line
is denominated the “ventral axis-line’” (SHuRRINGTON) or the “ventral
differential boundary” (BoLk) of the extremity.
As may be seen from the foregoing, there is a striking accordance
between the results of the researches on the dermatomata of those
authors, and the facts stated in this communication.
This accordance however goes still farther, for it is shown not
only in what may be called “normal” cases‘), but also in such
Fig. XXIV. Fig. XKV.
[Fig. VIII. 1. [Fig. VILL. 2.
TAY. Dog 19. Prefixion of the extremity ZIV. Dog 19. Prefixion of the extremity
(after Winkter and van Rusxperk)]. (after Winker and van Fiusnperk)).
1) In as much as the term “normal” may be applied to any relations concerning
the peripheral skin-innervation. According to the data of WINKLER and vAN RIJNBERK,
SHERRINGTON’s “prefixed” and “postfixed type’ must be considered as extrema
( 1160 )
cases where anomalies in the construction of the skeleton of the
vertebral column produce alterations in the dermatomery and in
shape, situation, and extension of the stryclhnine-segmental-zones.
Winker and van Risnperk in the course of their experiments have
met with one case (dog 19), where the dermatoma of 4. IV presented
a shape diverging from the “normal”, because in contrast with their
other cases of isolation of this skin-area, it sent a narrow linguiform
branch on the medial surface of the nether-leg!). (Fig. XXIV and XXV).
It was therewith characterized as it were as a transition form
between a LIV and LV dermatoma. At the autopsy the dog was
found to possess only 6 lumbar vertebrae, so this presented a case
of so-called “prefixion of the extremity” (SHERRINGTON).
In one of my cases (str. dog XIV) where I had applied strychnine
on the 4" lumbar segment, I found a zone shaped nearly identically
to that observed by Winker and van RunBerk in the case of
isolation of the £.1V dermatoma, described above. See Fig. XXVI
and XXVII. This dog was likewise found to possess only 6 lumbar
vertebrae.
/\«
Fig. XXVI. Fig. XXVII.
L.1V. Prefixion of the extremity. L. IV. Pretfixion of the extremity.
Sesides in this respect, this experiment is still interesting in
another way.
On page (439) 9 of their VII" communication the authors repeatedly
as regards the metamere skin-innervation, so that practically there exist numerous
intermediate forms. Among my results I find likewise several data, supporting this
conception. But speculations on this pomt, however interesting and important for
the question of the dermatomery, would lead me too far here.
1) WinkLER and vAn RinBerK, VIth communication l.c. page (321) 15. Fig. VIII.
( 1161 )
quoted by us, enter in elaborate details about the manner in which
the axis-lines’) of the extremity behave.
In Fig. XXVIIL I give a scheme of the demareation-line between
the strychnine-segmental-zones of II, Il], 1V, and SJ, as its course
was found to be according to my data, a line, as already stated
before, perfectly identical with the dorsal axis-line of the extremity,
described by Winkier and vAN RiJNBERK.
This line ends at the point, lying proximo lateral on the thigh, which
is common to the 1. V, “4. VI and “4. VIL zones, whence these zones
diverge like the sectors of a fan, largely overlapping one another.
And now the ventral axis-line.
Fig. XXVIII. Fig. XXIX.
——~ ® = demarcation-line between ----—=demarcation-line between strych-
strychnine-segmental zones of L. II, Ill, nine-segmental zones of ZL. II, Ill, [V,
IV, and SI. V, and SI.
payee NOUNGALY, Of ZONeLO Wn Vin | esreetes =caudal boundary of the zone of
+++—= , Se iete eet glues NE L.At after the demarcation-line.
ney =e oe a, woBANUE +++ = caudal boundary of the zones of
TZ. (Land IV after the demarcation-line.
Basing their conclusion on their “normal” material, but ‘likewise
on the abnormal cases and especially on their case “dog 19”,
1) As is well known, SHERRINGTON indicates as the characteristic of his axis
lines a functional specific quality, viz. the unimportant measure of the “overlapping”
of the dermatomata bounding one another in that region, whilst Bok for his
“differential boundary”, which is identical with this axis line, gives a morphological
characteristic, indicating as such the demarcation-line between dermatomata origin-
ally not lying next to one another, but pushed into each other’s neighbourhood
by the development of the extremity during its ontogenesis.
( 1162 )
Winkier and Runxperk, retaining withal the criteria of the definitions
of Bonk and Snerrineron, specified as ventral axis-line the line
going from the symphysis over the medial surface of the extremity
towards the malleolus medialis, passing in its course over the point
situated in the middle between epicondylus femoris and fossa poplitea.
Now this line is identical with the demarcation-line between the
strychnine-segmental zones of LI, III, and LIV on one hand and
of ST on the other, as described in the foregoing.
And this case of my Str. dog XIV gives still further confirmation
of that accordance, because it bears testimony (see fig. XX VII) that
is’. in cases of prefixion of the extremity the stryehnine-segmentalzones
too, like the dermatomata, are removed (apparently) caudalward on
the extremity, 2°. that this removal obviously takes place along the
demarecation-line that was proved to be the homologon of the ventral
axisline for the dermatomata. (See fig. X XIX).
Still in another respect 1 may point to analoga, even to identity.
In one of their first communications on the dermatomata the authors
quoted above have demonstrated that each filum radiculare of a
posterior spinalroot contributes to the innervation of the whole der-
matoma, founding this statement on the fact, that if from a pair of
successive posterior roots either only the cranial or only the caudal
fila radicularia were cut through, they never found a zone where
sensibility was destroyed, but on the contrary an area, corresponding
in extension with the number of posterior roots that were cut through
partially, presenting a uniform hyperalgesy.
In the course of my strychnine experiments I met with a similar
fact. It is not only the poisoning of the dorsal surface of an entire
segment that gives rise to the appearance of the strychnine-zone
characteristic for this portion of the spinal cord, but also if the
alkaloid is applied on part of it, e.g. on that part where the 2 cranial
fila radicularia enter, the strychnine-segmental-zone is seen to appear
in toto. And that this zone appears to its whole extent, is proved
moreover among others by the fact that it does not increase in size
if afterwards the strychnine is applied too on the remaining portion
of the dorsal surface of the segment.
Where the accordance existing in shape, situation, and extension
between the dermatomata defined by the isolation-method and the
strychnine-segmental zones found by this strychnine-method, is so
striking, it proves the truth of a presumption that obviously was
ours from the beginning, viz. that these strychnine-segmental-zones
present skinfields, identical as to the said attributes, shape, situation
and extension, with dermatomata.
( 1163 )
The facts here stated may lead to various theoretical speculations,
important for the physiology of the central=nervous system, and in
a further communication I hope to beZable to develop the theoretical
views following from our data, views touching on different questions
concerning the morphological foundations of the physiology of the
spinal cord, the functions of this organ and of the central nervous
system generally.
The conclusions, which I would propose as a summary of the
results of these researches, in as much as they concern the special
question about shape, situation and extension of the strychnine-segmental
zones, are the following:
I. After segmental application of strychnine on the dorsal surface
of the spinal cord the strychnine-syndrome, demonstrated by me,
appears tn sharply circumscribed skinjields, which are identical, as
regards their shape, situation, and extension, with the dermatomata
defined by means of the isolation method.
I. Jn this strychnine-method, ¢. e. the segmental, strictly localized
application of strychnine on the dorsal surface of the spinal cord,
we have got a new method, fundamentally different from all other
hitherto known methods, for the definition of the dermatomery of
the body.
Chemistry. — “Equilibria in the system: Water — Sodium sulphate
— Sodium chloride Copper sulphate
By Dr. F. A. H. ScHREINEMAKERS.
Cupric chloride’.
(Communicated in the meeting of March 28, 1911).
1. InrRODUCTION.
In a previous communication’) I discussed the equilibria which
occur at 30° in the system: Water — Ammonium - sulphate
— Ammonium chloride — Copper sulphate-Cupric chloride. I have
now replaced the ammonium salts in this system by the corresponding
sodium salts. This causes the equilibria to become more complicated,
and also their form to be more dependent on the temperature. For
this reason I have also investigated this system at different tempe-
ratures viz. at 35°, 25° and 15°.
At first sight one might think that the system is built up of five
1) These Proceedings XI p, 615.
( 1164 )
components; this, however, is not the case because between four of
these substances occurs the reaction :
Na,SO, + CuCl, @ CuSO, + Na,Cl,,
so we are only dealing with a quaternary system in whieh double
decomposition occurs.
In order to represent the equilibria in this system we take a
quadrangle; its apexes indicate the four substances CuSO,, CuCl,, Na,SO,,
and Na,Cl,, and in such a manner that the sulphate of the one
metal is connected by a diagonal with the chloride of the other
metal. In the intersecting point of the diagonals we take, perpendicularly
on the quadrangle, the axis on which the water content of the phases
is shown.
2. Tue isoturrm at 35°.
The equilibria occurring at 35° are represented schematically in
fig. 1. The sides of the quadrangle have been left out; only a portion
of the diagonals with their intersecting point W is drawn. Also,
the representation in space of the equilibria is not drawn but their
projection on the quadrangle is shown.
We will first consider the four ternary equilibria.
a. The system: water — Na,SO, — NaC.
At 35°, Na,SO, and NaCl only occur as solid phases. The isotherm
therefore consists only of two branches namely of the saturation line
of Na,SO, and of that of the NaCl. The first is represented by ak,
the second by Ak. Point a therefore, represents the solubility of the
Na,SO,, 2 that of the NaCl in water. The intersecting point & is
the solution which is saturated with the two salts simultaneously.
b. The system: water — NaCl — CuCl,.
At 35° occur as solid phases: NaCl and CuCl, . 2H,O. The isotherm
therefore, consists of two branches: /g is the saturation line of the
NaCl, fg that of the CuCl, .2H,O0. Point /, therefore, represents the
solubility of the NaCl, / that of the CuCl, .2H,O in water: g is the
solution which is in equilibrium with both salts at the same time.
c. The system: water — CuSO, — CuCi,.
In this system also, only two solid phases occur at 35° namely :
CuSO, .5H,O and CuCl, .2H,O. The saturation lines of these salts
are indicated by de and fe. Solution e is saturated with :
CuSO, . 5H,0 + CuCl, . 2H,O
( 1165 )
d. The system: water — Na,SO, — CuSO,.
In this system three solid phases occur namely : CuSO,.5H,0O,
Na,SO, and a double salt Na,Cu(SO,), . 2H,0.
The saturation line of the Na,SO, is represented by aé, that of
the CuSO,.5H,O by ed and that of the double salt by dc. Solution
6 is, therefore, saturated with Na,SO, and double salt, solution c
with CuSO,.5H,O and double salt.
e. The quaternary system.
Y sy
In this system occur at 35° as solid phases: NaCl, Na,SO,,
CuSO, .5H,O, CuCl, .2H,O and the double salt Na,Cu(SO,), . 2H,O.
As the quaternary solutions saturated with a solid substance are
represented by a surface in space (the saturation surface) we have five
saturation surfaces. Their projections are found in fig. 1.
fgmne is the saturation surface of CuCl, .2H,O
(iL en os a eNacl
ablk yee A 2 » Na,SO,
UGE en 8 er ot » CusO, .5H,0
Clim Cee ¥ - » Na,Cu(SO,), .2H,O
In order to obtain a better view, there is indicated in the figure
on each saturation surface the solid substance with which the solu-
tions are saturated. By way of abbreviation we have represented
( 1166.)
CuSO, .5H,O by Cu,, CuCl,.2H,O by Cu,, Na,SO, by Z, and
the double salt Na,Cu(SO,), .2H,O by D.
The intersecting lines of the saturation surfaces are the saturation
lines; these represent the solutions which are saturated with two
solid substances simultaneously. The following ones are found:
en the saturation line of CuSO, .5H,O + CaCl, . 2H,0
mmr ,; 2A » 9, CuCl, .2H,O0 + Na,Cu(SO,), . 2H,0
mY 5 oA »» », CuCl, . 2H,O0 + NaCl
TV a, os » 9», NaCl + Na,Cu(SO,), . 2H,0
Bil os, : » » NaCl -+ Na,SO,
Bile; " » » Na,SO, + Na,Cu(SO,), . 2H,O
Cn ;; - » », CuSO, .5H,O + Na,Cu(SO,), . 2H,0
In addition we have three saturation points, namely, points which
represent a solution saturated with three solid substances. They are
the following:
n saturated with CuSO, .5H,O + CuCl, . 2H,O + Na,Cu(SO,), .2H,O
m 55 » NaCl + CuCl, .2H,O + Na,Cu(SO,), . 2H,O
1 34 » Na,SO, + NaCl + Na,Cu(SO,), . 2H,O
As may be readily noticed from fig. 1 in presence of solution
there can exist
CuSO, .5H,O by the side of CuCl, .2H,O or Na,Cu(SO,), . 2H,O
but not to NaCl of Na,SO,.
CuCl, . 2H,O by the side cf CuSO, .5H,0, NaCl or Na,Cu(SO,),.201,0
but not to Na,SO,
NaCl by the side of CuCl, .2H,0, Na,SO, or Na,Cu(SO,), . 2H,O
but not to CuSO, . 5H,0
Na,SO, by the side of NaCl or Na,Cu(SO,), . 2H,O
but not to CuSO,.5H,O of CuCl, .2H,0
Na,Cu(SO,), .2H,O can exist by the side of each of the other salts.
In table I are indicated the compositions of different solutions in
Mol. °/,; the double salt Na,Cu(SO,), 2H,O is represented by D.
TAB IE we
Compositions in Mol. % ) at 35°.
Point. H,O CuSO, CuCl, Na,;SO, Na,Cl, Solid phase.
f. 90.311 0 9.689 0 0 CuCl;.2H,O
é. 90.108 0,592 9,300 0 0 CuSO ,.5H,0+CuCl,.2H,0
g. 88.387 0 ; 8.708 0 9.905 ; NaCl+-CuCl;.2H,0
fi 90,314 0 9.689 0 0 CuCl,.2H,O0
( 1167 )
é. 99.108 0,592 9,300 0 0 CuSO,.5H,O +CuCl,.2H,0
B® 89.795 0.669 9.034 0 0.502 Set Ae
n. 89482 0.773 8796 0 0.949 — CuSO,.5H,0+CuCh.2H,0+D
n. 89482 0.773 8798 0 0.9% CuSO,5H.O4CuCI,2H,O+D
EE 9909 0437 870 0 1.759 CuCl2H,O+D
in €8.132 0.299 8.486 0 3.083 CuCl,.2H,O+NaCl+D
gz 88387 0 8708 -0 2905 NaCl4}CuCl,2H,O
m. 88132 0.299 8486 0 3.083 NaCl+CuCl,.2H,0+D
e 90108 0592 9300 0 0 CuSO,5H,0+CuCi,9H,0
d. 97.079 29% 0 0 0 CuSO,.5H,0
A cs\500 Sea eaa non ninmnl on) | GusosHtoeD
d. 97.079 2921 0 0 0 CuSO,.5H,0
c. 95590 2895 0 1515 0 CuSO,.5H,O+-D
= 95.019 1.566 1.300 14550 = EEX
- 95.310 9.336 0,922 0 1.432 a aL
= 99961 41.913 4590 0 1.236 a ae
n. 90482 0.773 &776 0 0.919 CuCl,2H,O+CuS0,.5H,0+D
c 95.590 2.895 0 4.515 0 CuSO,.5H,O+D
b. 94.00% 0.235 0 5.761 0 Na,SO,+-D
a. 4106 0 0 5.804 0 Na,SO,
b. 94.004 = 0.285—Ss«OO 5.761 0 Na.SO,+D
6. 94.004 0.935 0 5.761 0 Na.SO,+D
- 94435 0.200 0 4.080 285 4 7 elle x
> 94600 0498 © 2610 2.50% Page
= yee tere a 1575 3.738 ae
L 98814 0482 0 0.629 3.965 NaCl-+Na.SO,+D
a. 94,106 0 0 5,894 0 Na,SO,
k. 94130 0 0 1.041 4.829 Na,SO, + NaCl
hk 94430 0 0 4.041 4929 Na,SO,+ NaCl
Ai 94.721 0 0 0 5.279 NaCl
bk 941900 0 1.041 4.829 Na,SO,+NaC!
L 93.814 + =0482—S«OO 0.639 5,065 Na,SO,+-NaCI+-D
( 1168 )
A. 94,721 0 0 0 5.279 NaCl ;
g. 88.387 0 8.708 ) 2.905 NaCl+ CuCl;.2H,O0
l. 93.814 0,482 0 0.639 5,065 Na,SO,-++NaCl+D
92419 0 1.218 0.758 4.605 NaCl+D
e 93.023 0.550 1.606 0 4,821 sto
= 92.089 0.445 3.177 0 4239 » Ee»
2 91.195 0.389 4.506 0 Rea }M(0) » Fn
89.023 0.311 7.599 0 3.107 » ty
m. 88.132 0.299 R486 0 2,083 CuCl;.2H,O+NaCl+ D
When studying the given compositions of the solutions we must
remember that these may be expressed in different ways.
Let us take a solution which contains:
a Mol CuSO,, 4 Mol CuCl,, ce Mol Na,SO,
and, therefore, 100—a—b—c Mol H,O.
In consequence of the relation ;
Na,SO, + CuCl, 2 CuSO, + Na,Cl,
we may also express the composition as:
a+ aw Mol Cuso,, b —« Mol CuCl,, c —a Mol Na,SO,,
v Mol Na,Cl, and 100—a—b—c Mol H,O.
We notice that, in this manner, the composition of a phase may
be expressed in an infinite number of ways.
If b on NassO;, -— Nazs0; 510 EO
quia. * » » Na,SO,.10H,O + Na,Cu(SO,), 2H,0
GB oe a » » CuSO, .5H,0-—— Na,Cu(SO,),. 280
Instead of three saturation points as at 35°, four are found here
namely :
n saturated with CuCl, .2H,O + CuSO,.5H,O + Na,Cu(SO,), .2H,0
m * », CuCl, .2H,0 + NaCl + Na,Cu (SO,), .2 H,O
l a4 » NaCl-+ Na,SO, + NaCu (SO,), . 2H,O
q 3 » Na,SO, + Na,SO, .10H,O + Na,Cu (SO,), . 2 H,O
As may be readily deduced from fig. 2, at 25°, in presence of
solution there can exist:
CuSO,.5H,O by the side of CuCl, .2H,0 or Na,Cu (SO,), .2H O
but not to NaCl, Na,SO, or Na,SO, .10H,0.
CuCl, .2H,O by the side of CuSO, .5H,O, NaCl or Na,Cu (SO,),.2 H,O
but not to Na,SO, or Na,SO,.10 H,0.
C1171)
NaCl by the side of CuCl, .2H,0, Na,SO, or Na,Cu (SO,), . 2 H,O
but not to CuSO,.5 H,O or Na,SO,.10 H,O
Na,SO, by the side of NaCl, Na,SO,.10H,O or Na,Cu(SO,),.2 4,0
but not to CuSO,.5H,0 or CuCl, . 2 H,O0
Na,SO,.10H,O by the side of Na,SO, or Na,Cu (SO,), . 2 H,O
but not to NaCl, CuCl, .2H,O or Na,Cu (SO,), . 2 H,O
Na,Cu (SO,), .2 H,0 by the side of all other solid substances.
In table I
Point.
Sf
line
(4
vi)
m.
line dy.
HO
90.695
90.534
90.695
89.014
89.014
88.922
90.534
90,210
89.760
89.760
89.733
88.922
89.014
4,075
88.922
89.840
90,700
90.851
91.371
92,222
92.924
93,362
are given the compositions of the solutions in mol. °/,.
Compositions in mol. °/, at 25°.
RABLEE I
CuSO, CuCl, Nas;SO, Na,Cl, Solid phase.
0 9.305 0 0 CuCl,.2H;,0
0.424 9.042 0 0 CuCl,.2H,0 +CuSO,.5H,0
0 9.305 0 0 CuCl,.2H,0
0 8.193 0 9.793 CuCl,.2H,O-+NaCl
0 8.193 0 2.793 CuCl ;.2H,0+ NaCl
0.284 7.994 0 2.800 CuCl,.2H,0+-NaCI+D
0,424 9,042 0 0 CuCl,.2H,0+CuSO,.5H,0
0.502 8.692 0 0.596 Fs Fs
0.587 8.428 0 1.295 CuCl,.2H,0+CuS0O,.5H,0+-D
0.587 8.428 0 1.295 CuCl;.2H,O+CuSO,.5H;,0+-D
0.392 8&8 271 0 1.604 CuCl,.2H,O+D
0.284 7.994 0 2.800 CuCl,.2H,O+NaCl+-D
0 8.193 0 2.793 CuCl;.2H,O0+NaCl
0 0 0 5.25 NaCl
0.984 7.994 0 2.800 CuCl,.2H,O+NaCl+-D
0.299 6,651 0 3.210 NaCIl+D
0.353 5.510 0 3.437 am dee
0.352 5.314 0 3,483 5 ABs
0.386 4.391 0 3,852 5 ae
0.493 3.234 0 4A tLe
0.491. 2.126 0 4459 4 ay,
0 1.839 0.57 4.226 » #y
1
1
1
( 1972) )
93.779 0 1167 0.024 4.433 » +»
93,939 0 0582 0.96% 4.515 » ty
93,857 0 OAT4 1,082 487 » +»
93,862 0 0.377 1.239 4.522 » ty
l. 93,840 0 0.371 1.269 4520 NaCl +D-+Na,SO,
A. 94.75 0 0 0 5.25 NaCl
Rk. 94.122 0 0 1.163 4.715 NaCl-+-Na,SO,
94.122 0 0 1.163 4.715 NaCl - Na,SO,
p. 94,60 0 0 2.57 2.83 Na,SO,.10H,O-+Na,SO,
p. 94.60 0 0 2.57 2.83 Na,SO,.10H,0 +Na,SO,
a. 06,57 0 0 343 0 Na,SO,.10H,0
k. 94 AD 0 0 1163 4.715 NaCI+-Na,SO,
if 93.840 0 0.371 1.969 4.520 NaCl -Na,SO,+D
D: 94.60 0 0 O57 2.83 Na,SO,.10H,;0 +Na,SO,
gq. 94444 0184 0 2546 2.826 Na,SO,.10H,O+Na,SO,+D
l. 93.840 0.371 0 0.898 4.891 NaCl+-Na,S0O4+-D
p 93,984 0.355 (8) O.955 4,742 Na,SO,-+-D
Ss
» 94198 0.951 0 1.483 4.968 » ty
=I
= 94.468 0.200 0 QA01 3,934 3 Ee
q. 94.444 0184 0 2.546 2826 Na,SO,.10H,0+Na,SO,+D
a. 96,57 0 0 3,43 0 Na,SO,.10H,O
b. 93.525 0,934 0 3.541 0 Na,SO,.10H,0+D
b. 95.525. 0.934 0 3.541 0 Na,SO,.1/H,0+D
95.569 0,680 0 3.234 0.517 F +,
>
95.515 0.580 0 2.069 0.836 3 ae
=I
= 954i 0.894 0 9.793 1,502 F oo
g. . 94444 OA84 0 2546 2,826 Na,SO,4+-Na,SO,.10H,0+D
b. 95.525 0.934 0 3.541 0 Na,SO,.10H,0 +D
(a 95,641 2519 0 1.840 ) CuSO,.5H,0+D
C. 95.641 9519 0 1.840 0 CuSO,;.5H;,0 + D
d. 97.546 2.454 0 0 0
CuSO,.5H,O
(1173 )
95.641 9519 0 1.80 0 CuSO,.5H,O0+D
95,805 41,024 1446 1.726 0 . +,
_ 94.659 1,406 9.313 0 1,622 aL
5 93.596 41,063 3,804 0 1,537 f aie
= 94.744 0,909 -F.847 0 1.500 ‘ ae
91.087 0.682 7.088 0 1,198 ‘ He
n. 89.760 0.587 8 428 0 1,225 CuCl,.2H;,O0 +CuS0O,.5H,0-+ D
d. 97.546 2,454 0 0 0 CuSO,.5H,0
e 90.5384 0,424 9.042 0 0 CuCl,.2H,0+CuS0 ,.5H,0
96.405 0.687 0 2,509 0.399 D
Q
of 95.574 0.664 0 2.960 0,802 5
1S)
os
= 94,689 0 1.831 0.852 2618 i
=}
n
93.078 0.603 3.589 0 2.730
5. The isotherms between 25° and 15°.
On decrease of temperature the isotherm at first retains a form as
in fig. 2; the points 4 and c however approach each other, also the
points p and #, and the points g and /.
At 17,9° the points p and / coincide causing the saturation line
pk of the anhydrous Na,SO, to disappear. The quadrangle (of course
with curved sides) is then reduced to a triangle with the apexes , /
and the point at which p and / coincide. On further decrease of
temperature this triangle gets smaller and disappears at 17.4° in a
point. The solution represented by this point is saturated with four
solid substances; if we also include the vapour there are six phases
in equilibrium, so that we have a sextuple point.
As four components are present in six phases, this system is non-
variant.
These phases are:
Na,SO, + Na,SO, . 1OH,O + NaCl + Na,Cu(SO,), . 2H,O
+ solution + vapour
Below 17°.4 the saturation surface of the Na,SO, therefore, dis-
appears and the saturation surface of the Na,SO,.10H,O borders on
that of the NaCl.
On further decrease of temperature the points 6 and ¢ rapidly
move towards each other; at 16°.7 they coincide. Below this tem-
perature the double salt Na,Cu(SO,), .2H,O therefore disappears fron’
the ternary system: water—Na,SO,—CuSO,. The double salt then
(divs)
still exists only in quaternary solutions; the isotherm then assumes
a form as in fig. 3.
6. The isotherm at 15°.
The equilibria occurring at 15° are represented in fig. 3; this is
at once distinguished from that at 25° (fig. 2) by the disappearance
of the saturation surface Z, and because the saturation surfaces of”
CuSO,.5H,O and Na,SO,.10H,O are partly joined along the line
tu. The equilibria in the ternary systems water—NaCl—CuCl, and
water—CuSO,—CuCl, still belong, at 15°, to the same type as at
25° and 35°; these need not, therefore, be discussed any further.
The equilibria in the two other ternary systems are however, at
15°, different from what they are at 25° and 35°; we will, therefore,
briefly discuss these first.
a. The system water — Na,SO,— NaCl.
At 15°, only Na,SO, .10 H,O and NaCl occur as solid substances; the
point 7 is, therefore, the solution saturated with Na,SO, . 10 H,O+-NaCl.
The saturation line of the NaCl is represented by /r, that of the
Na,SO, .10H,O by ar.
b. The system water — CuSO, — Na,SO,.
Owing to the disappearance of the double salt Na,Cu (SO,), . 2 H,O
the isotherm consists only of the saturation line at of the Na,SO, . 10 H,O
and of the saturation line dt of the CuSO,.5H,O. Solution ¢ is
saturated with both salts.
c. The quaternary system.
The following saturation surfaces are found:
Jenmg the saturation surface of CuCl, .2 H,O
hgmsr,, a PS =e Nal
atusr —_,, se “3 5 oNa SOF tO nO
dtune ,, a _ » CusO72 a HO
wsmn “s a » Na,Gu (SO,) . 2 H,0
Further, we find the saturation lines :
en the saturation line of CuCl, .2 H,O + CuSO, .5 H,O
LO ys » », CuCl... 2\0,0 =] Na,Ga(s0)). 2 2820
MG iss = » » CuCl, .2 H,0 + NaCl
( 1175 )
TS 35 » » NaCl Na,Cu (SO, .2 H,O
She 35 i » », NaCl -+ Na,sO, -10H,0
SU) Pe < >» 3» Na,sO, .10H,0 + Na,Cu (SO,), . 2 H,O
UT ae + nto CusO,. 9 H:O.-- Na. Cu(S0,)..- 2 H@
WOT War 5 CuSO) oO HeO RNa: SO... 10 HO:
We also find four saturation points:
n saturated with CuSO, .5H,0 + CuCl, . 2H,0 + Na,Cu (SO,), . 2H,O
m ap », CuCl, . 2H,0 + NaCl + Na,Cu (SO,), . 2H,0
iS > » NaCl + Na,SO, .10H,O + Na,Cu (SO,), . 2H,O
u 3 » CuSO,.5H,0 + Na,SO,.10H,O + Na,Cu(SO,), 2H,O.
Ma, $0,
Fig 3.
As will be readily seen from fig. 3, at 15°, in presence of solution
there can exist:
CuCl, .2H,O by the side of CuSO,.5H,O, NaCl or
Na,Cu (SO,), .2H,O but not to Na,SO,.10H,O;
CuSO,.5H,O by the side of CuCl,.2H,O, Na,SO,.10H,O or
Na,Cu(SO,),.2H,O but not to NaCl;
NaCl by the side of CuCl, .2H,0, Na,SO,.10H,0 or
Na, (SO,),. 2 H,O but not to CuSO,.5H,0O;
Na,SO,.10H,O by the side of CuSO,.5 H,O, NaCl or
Na, Cu (SO,), . 2 H,O but not to CuCl, .2 H,0;
Na,Cu (SO,), .2 H,O by the side of all other solid substances.
In table III are given the compositions of the solutions.
( 1eb7'o)
TABLE IIk
Compositions in Mol. 9, at 15°.
Point. H,0O CuSO, CuCl, Na,SO, Na,Cl, Solid phase.
fr 91,066 0 8.934 0 0 CuCly.2H,0
e, 91,0290 0931 8749 0 0 CuCl).2H,0+-CuSO,.5H,0
ip 91,066 0 8.934 0 0 CuCl).2H,O
g. 89,519 0 7,888 0 2.593 CuCl).2H,0-+-NaCl
e. 91,020 0.2381 8,749 0 0 CuCl,.2H,0 +CuSO,.5H,0
n, 90,023 0455 7,959 0 1.563 CuCl,.2H,0+-CuSO,.5H,0+D
&. 89,519 0 7.888 0 2.593 CuCl,.2H,0-+-NaCl
m, 89.509 0,959 7.661 0 9.571 CuCl).2H,0-+-NaCl+-D
n. 90,023 0.455 ~—-7.959 0 1.563 CuCl,.2H,O+CuSO,.5H,0+D
m. 89.509 0.959 7.661 0 9571 CuCl,,2H,O+-NaCI+-D
g 89.519 0 7.888 0 2.593 CuCl,.2H,0+NaCl
h. 94.78 0 0 0 5.22 NaCl
m. 89.509 0.259 ~— 7.661 0 2.571 CuCl.2H,0+NaCl+D
yj 92420 0.439 3.157 0 3.984 NaCl+D
. 93.448 0.557 4164 0 4,831 Ses
= 93.880 0.738 (0.312 0 5.070 ~ ak.
s. 93,947 0.494 0 0.595 4.964 Na,SO,.10H,O+NaCI+D
h. 94,78 0 0 0 5,22 NaCl
ifs 94,26 0 0 0.95 4.79 Na,SO,.10H;0-+-NaCl
s. 93947 0.494 0 0.595 4.964 Na,SO,.10H,0-+-NaCl+-D
is 94.26 0 0 0.95 4.79 Na,SO_.10H,0+NaCl
r. 94.26 0 0 0.95 4.79 NasSO,.10H,O--NaCI
a. 98.36 0 0 1.64 0 Na,SO,.10H,O
s) 93947 0404. «0 ) 0505) 4.960) NasSO, 10H,0-LNaGLED
94.676 0,711 0 0.365 4.248 = Na,SO,.10H,0+D
S 95.229 0.480 0.251 3,572 : an
= 95.763 4982 0 0.400 9.555 : ae
95,924 41,839 0 0.987 1,250 E oe
u. 95,901 0
9.038
1.09%
0,967 CuSO,.5H,0-++Na,SO,.10H,0 +D
(PLAAe
a 98.36 0 0 1.64 0 Na,SO,.10H,O
t 95,83 2.4 0 1.93 0 Na)SO,.10H,O-+CuSO,.5H,O
t 95.83 2.24. 0 1.93 0 NaoSO,.10H2,0+CuSO,.5H20
ES 95861 2099 0 1502 0.538 ‘ a ;
u. 95.99) 2,038 0 1.09% 0.967 NagSO,.10H,0 4+-CuSO,.5H20 + D
t. 95.83 2.24 0 1,93 0 Na,SO,.19H O-+-CuSO,.5H,O
d. 97.89 11 0 0 0 CuSO,.5H,0
u. 95.901 2,038 i) 1,994 0.967 NaoSO,.10H20 +CuSO ,.5H,0+D
95.572 9.032 0.277 0 2.119 CuSO,.5H,0+D
94.701 1158 2137 0 2,004 2 ds
= 94,433 1,060 2.533 0 1,974 i; +,
= 93466 0.773 4192 0 1,869 4 aoe
4 92.056 0.598 628 0 1.718 ; +,
OQ1.418 0.523° 6.652 0 1.707 oh.
n. 90.023 0.455 7.959 0 1.563 CuCl,.2H,0+4+CuS0,.5H,0-4-D
; eee 91.29 Dae ; 0 ton 0 NN GusOlcH.o i, a
é. 91.020 0,231 8.749 0 0 CuClo.2H,0 + CuSO, 5H2,0
Siniace D. 93.265 0.62) 3.395 0 2.681 - eens . a
In most cases the appertaining residues at 15°, 25°,
and 35° have
been analysed as well as the solutions, and the solid phases with
which the solutions were saturated have been deduced therefrom
by means of the usual method.
(To be continued).
Chemistry. — “Hypaphorine and the relation of this substance with
tryptophane”. By Prof. P. vax Rompurau.
(Communicated in the meeting of March, 25, 1911).
In the seeds of Erythrina Hypaphorus Boerl. (Hypaphorus subum-
brans Hassk.) which, under the name of ‘“dadap minjak” is generally
cultivated, in Eastern Java, as a shading tree in coffee gardens,
Gresnorr') has found a poisonous alkaloid.
In the end of 1891 Dr. Gresnorr
hand, jointly, the study of
had invited
alkaloid in
me to take in
order to determine
afterwards Dr. GresHorr was obliged, in the
this
iis structure. Shortly
course of 1892, to return to Europe. In the beginning of 1892 I
1) Mededeelingen uit ’s Lands Plantentuin 7, 29 (1890).
(Cai3")
was engaged for some time on the investigation of the “dadap sub-
stance’, but suspended the work after his departure from Java,
In 1898 appeared a communication‘) on hypaphorine, the name
meanwhile given to the substance obtained from the “dadap seeds”,
from the hand of Dr. (Gresnorr, in which, however, the results
obtained by myself, were not included.
In that communication are given the method of preparation of
hypaphorine and also its properties.
As regards its properties it may be mentioned here that hypa-
phorine erystallises in hydrated transparent crystals, which effloresce
ina desiceator. At 255° it melis without decomposition. On being heated
strongly in the air it burns with evolution of vapours having an odour
resembling indol. It has a right-handed rotation |@| p= + 91°—98°.
Although hypaphorine possesses a neutral reaction, it yields with
acids crystallised compounds of which the sparingly soluble nitrate
is particularly characteristic. No formula could be deduced from the
recorded analyses of the hypaphorine and its nitrate. In the “Index
Phytochemicus” by Rirsema and Sack, published in 1905, the formula
C,,H,,N, 0, is, however, given for hypaphorine, but without any
mention being made of the source.
After the decease of Dr. Grusnorr, I applied to the Committee of
the Colonial Museum at Haarlem with the request to forward me
the preparations of hypaphorine from the laboratory of the Museum
in order to enable me to continue the investigation, started previously
at Buitenzorg. | have to tender my sincere thanks to that Committee
for the great willingness with which, a few months ago, my request
was complied with.
The elementary analysis of the anhydrous hypaphorine gave me,
at Buitenzorg, the following results :
C 68.4; 68.4. Hi 708)9 7-63: N 10.9; 11.—.
Calculated for C,, H,, N,O:2 (© 68245 JH ssa Nesey:
The hydrochloride gave: 13.1 °/, ; 13.1°/, HCl.
Calculated for C,, H,,N,O,.HCl: 12.95 °/, HCI.
On heating with strong aqueous potassium hydroxide, hypaphorine
is decomposed. A gas having an amine-like odour is evolved and the
aqueous distillate contains oily drops, which solidify after a while.
The gas evolved was collected in dilute hydrochloric acid and. the
solid matter was separated by filtration from the aqueous distillate.
The aqueous solution was united with the hydrochlorie acid in which
the said amine had been absorbed and evaporated. From the brown
1) Mededeelingen uit ‘s Lands Plantertuin 25, 54 (1898),
( 1179 )
coloured salt the amine was then again liberated, combined with
hydrochloric acid and converted into the platinum chloride compound,
which was analysed.
Found 36.8°/, Pt., the calculated percentage for {(CH), N.HC1), PtCl,
being 36.94. The amine found is, therefore, trimethylamine.
The substance distilled over with the water, had a strong faecal
odour and melted at 52°. It contains nitrogen.
Analysis: Found: C 82.2 H6.24 N 11.72.
Calculated for C,H,N : C 82.-, H 6.04, N 11.96.
With s. trinitrobenzene it Fata an additive compound m. p. 187°
crystallising in golder yellow needles; it proved to be identical with
a product formed from indol and s. trinitrobenzene ‘*).
During the action of potassium hydroxide indol as well as trimethy F
amine has, therefore, been formed.
The behaviour of hypaphorine towards nitric acid pointed to its being
a urea derivative, but this view could now no longer be entertained.
Experiments, intended to elucidate the structure, carried out in my
laboratory by Mr. Hortappri and consisting in the oxidation of
hypaphorine with potassium permanganate and sulphuric acid, or
with hydrogen peroxide in either neutral or alkaline solution led to
no result except that the formation of trimethylamine could be
demonstrated. Heating with hydrochloric acid, which caused charring,
did not yield the desired result either. Oxidation experiments with
ferric chloride are still in progress.
From the decomposition with potassium hydroxide in which indol
and trimethylamine were obtained and which had rendered it
probable that hypaphorine is a betaine, one feels inclined to look
upon it as being derived from an amino acid belonging to the indol
series and having the formula (,,H,,N.O,.
Among the acids which satisfy that condition we tind mentioned
in Ricuters Lexikon (Suppl. IJ) tryptophane to which belongs,
according to Eniincer’s*) synthesis, the structural formula:
CH
NC 6 _ CH Cre COOH
| | | NH,
ENA 1018
CH NH
Through the great kindness of our fellow member Prof. PEKELHARING,
to whom | feel very grateful for this, | had come into possession
15% 14, 66 (1895).
) B. 40, 3029 [1907].
( 1180 )
of 0.20 gram of tryptophane. This, according to the classic method
of Pwrer Grirss '), was mixed in methyl! alcohol solution with sodium
hydroxide and an excess of methyl iodide. After a few hours,
the alcohol and the excess of methyl iodide were removed by distil-
lation in a waterbath. If now the residue is taken up with a little
water and mixed with dilute nitrie acid a nitrate crystallises in delicate
needles when the sides of the beaker are rubbed with a glass rod.
1 obtained about 0.12 eram of the nitrate.
The nitrate exhibits in its reactions the greatest resemblance with
the nitrate of hypaphorine. Like the latter it has no sharp melting
point; at about 220° the two preparations contained in capillary
tubes were converted amid effervescence into a black mass. This
decomposition point depends on the manner of heating.
On boiling with aqueous potassium hydroxide the synthetic nitrate
also yields vapours having an odour of amine and indol *).
From the experiments described we may draw the conclusion that
it is highly probable, that hypaphorine is identical with @-trimethyl-
8 indolpropio-betaine :
i Nee VEG = C2 = 0
ee le |
KR of CH N-—O
SNA. (CH),
derived from tryptophane.
In order to get perfect certainty and°also to be able to perform
the required analyses, I intended to carry out the synthesis of this
betaine on a larger scale, when last week | received from Dr. Barer
in London a letter communicating that by methylating tryptophane
according to ENGELANp*) and treating the product formed in this
reaction with dilute aqueous potassium hydroxide, he had obtained
a betaine, the nitrate of which has the same properties as that of
hypaphorine. A determination of the rotatory power could be made.
Found |@]p = + 94° whereas Grusnorr states + 91—92°.
In consequence, | limit myself to the short, preliminary communi-
cation of my results and intend to return to the synthesis, jointly
with Dr. Barenrr.
Utrecht. Org. Chem. Lab. University.
1!) B. 8, 1406 [1875].
2) Tryptophane when boiled with strong aqueous potassium hydroxide certainly
yields a distillate which gives with HNO; the indol reaction, but with hypaphorine
the splitting takes place much more easily, which fact is not readily accounted for
by the formula
3) B. 42, 2962 [1909]; 48, 2662 [1910}.
( 1181 )
Physiology. — “A new method of determining the arterial blood-
pressure in man; at the same time an attempt at estimating
the influence of the arterial wall on it’. By Dr. D. pe Vrirs
LEILINGH. (Communicated by Prof. Wrxcoxepacn).
(Communicated in the meeting of March 25, 1911).
I. A SHORT SURVEY OF THE USUAL METHODs.
The arterial blood-pressure in man was in the beginning determined
according to the older methods of von Bascu, von Frny, Porain, and
others. By these methods, as the newer methods of investigation
teach us, only an approximate estimation was obtained.
A great improvement in the solution of the problem was obtained
by the invention of Riva-Rocct and Hitt and Barnarp i.e. by the
method of the circular compression of the arm by a hollow rubber
armlet in which the pressure could be increased and diminished.
Originally only a narrow armlet was used, but von R&CKLINGHAUSEN
showed that the influence of the surrounding tissues of the arm was
considerably less, if an armlet of at least 13 ¢.m. broad was used.
Since that time this broad armlet ts almost universally used. LronarD
Hint even makes the determinations of the blood-pressure with an
armiet of 20 em. broad.
Now the blood-pressure is usually measured according to two
different principles, according to which it is customary to distinguish
the oscillatory and the palpatory method.
A. Oscillatory method.
A hollow armlet is applied to the upper-arm of the person that
is to be examined, whilst the pressure of air in the interior of the
armlet is constantly increased. Then there occur in the armlet
pulsations, the intensity of which can be determined in some way
or other: either by registering them graphically on a revolving drum
or by reading them from a mercury- or water-column or any other
index connected with the armlet.
The peculiarity of these pulsations is that they increase in the
same measure as the pressure in the armlet increases, till they have
reached a certain maximum, and that afterwards, when the pressure
in the armlet augments, they decrease and disappear at last almost
entirely.
Originally it was admitted, that the diastolic or minimal blood-
pressure (mp) in the armlet was reached when it showed the
greatest pulsations. It was supposed that just then the artery during
( 1182 )
the diastole was completely closed by the pressure of the armlet,
but that it could expand itself still fully during the systole of the
heart, so that, at that moment, the differences in width of the artery
during the two phases of the heart were greatest.
And the current view was that the systolic or maximal blood-
pressure (Bp) in the armlet was reached when the latter showed
no longer any or hardly any pulsations. It was admitted that then
the artery, likewise during the systole of the heart, was tightly
compressed by the armlet, so that it could no longer transfer pulsations
to the armlet,
Both these theories are objectionable.
In the first place the investigators very soon held different views
about the pulsations of the air in the armlet that indicated that the
mBp was reached. Originally they were inclined to suppose that
at the moment, when the maximal pulsations were observed, there
was mBp in the armlet. Afterwards they thought that the mbp
in the armlet was reached, when the pulsations in it at increasing
pressure began to become greater. The pressure of the armlet was
thought to be at that moment just a little greater than the diastolic
pressure in the artery. Consequently this artery would be a little
compressed during the diastole of the heart. From this moment
therefore the fluctuations of volume in the artery would begin to
increase, and they would transmit themselves to the air in the armlet
so that there the fluctuations of volume would likewise increase at
that moment (v. RECKLINGHAUSEN, ERLANGER, WyBAUW).
We shall revert to this afterwards, but we must now already
call attention to the fact, that on this point the views are still
divergent, and that we are still in uncertainty at which pulsations
the mBp in the armlet is in reality reached.
Moreover the intensity of the pulsations usually increases and
decreases so imperceptibly, that it is extremely difficult exactly to
draw the line between large and largest pulsations, and consequently
too great a margin remains for the subjectivity of the investigator.
The divergency of views with regard to the 6p. is still greater.
Soon it appeared that the pulsations in the armlet never ceased
entirely, not even if the pressure in it was made very strong. Most
likely this may be attributed to the fact that the artery palpitates
proximally against the armlet. One tried now to neglect these
smallest pulsations, and placed the moment of the J//p there, where
the pulsations began to decrease. But very often also this moment
cannot be exactly determined.
These considerations suggested to WysBauw, on the track of Oliver,
( 1183 )
the idea of constructing a double armlet, the proximal band of which
was to receive those so-called “Rand-Pulsationen” whilst a separate
distal-band, was connected in a peculiar way with a writing-apparatus
(Ertancer) and noted the fluctuations of volume of the artery.
Wrsauw however placed the two bands close to each other. And
now it appeared to us that even with a pressure in the two bands
greater than the J/4p the “Rand-Pulsationen” were still transmitted
by the upper band to the lower one (compare the curves).
With the present pretty well general use of the broad armlet
only Sanit still uses the narrow one) another difficulty presents itself.
Let us first consider the M/p.
If in the broad armlet a pressure is made, that is a little less
than the Mp, then the armlet will already be able to close the
artery, for just because the armlet is so broad, part of the pressure
of the artery will be spent under the armlet. Consequently the pres-
sure in the artery at the lower edge of the armlet will become less
than that at the upper edge, whilst the latter is equal to the M/Bp.
he pulsations transmitted to the armlet will thus become smaller,
before the M/6p is reached in it. With Sanit we are of opinion
that this is an objection io the broad armlet. It will be the question
if the advantage with regard to the surrounding tissues, that the
broad armlet undubitably affords (v. RickLINHHAUSEN), Compensates
this disadvantage. At all events it would be desirable, that it was
generally agreed always to use an armlet of a definite breadth in
order to obtain figures that can be compared.
It will at all events have become evident that for the determination
of both the J/5p and the mp, according to this method, much is
left to the subjectivity of the investigator. It appeared to us during
the observations, made with Wysavw’s apparatus, that, on account
of the imperceptible increase or decrease of the pulsations, it is
extremely difficult exactly to read the two moments.
B. Palpatory Method.
If one causes the pressure gradually to increase, two moments
can be observed at the palpation of the distal pulse. In the first place
a moment at which that pulse becomes less intense and secondly a
moment at which it disappears. At the first moment the msp, at
the second the Wp would be reached in the armlet.
For if the pressure of the armlet > the diastolic pressure in the
artery, the artery will be closed for 2 moment during the diastole
of the heart. Then a certain force will be required to press the artery
( 1484 j
open: part of the systolic pulse-wave is consequently checked, distal
the pulse becomes less intense.
If further the pressure of the armlet > the systolic pressure in
the artery, then even during the systole of the heart the artery
remains closed, and consequently the whole pulse-wave is checked:
distal no pulse can be felt any longer.
The objections made above against the broad armlet prevail here
likewise. As however the surrounding tissues of different persons
are likely to be more variable than the part of the pulse-wave that
is spent under the armlet, it is perhaps better to continue using the
broad armlet. Yet, exactly under a broad armilet, the possibility exists
that before the M4/p is reached in it, the pulse-wave, as a wave,
is annihilated, and the blood continues to ooze (PAacnon), which,
however, cannot be observed at the distal pulse by palpation.
(Société de biologie, June 1909).
However, objections exist, both against the determinations with the
broad armlet and against those with the narrow one, which do not
result. from the method of compression but from the palpation of
the distal pulse. If it is already often difficult exactly to observe
the moment of the disappearance (or the return) of the pulse, the
observation of the exact moment of the decrease of the pulse offers
very great difficulties. Consequently this method as well leaves too
ereat a margin for the subjectivity of the investigator.
Therefore Santi tried to register the two moments. For this pur-
pose he placed a sphygmograph on the distal pulse. Consequently
sphygmographically the decrease and the disappearance of the pul-
sations was recorded. When applying this method Sani experienced
some difficulties, which were chiefly caused by the veinous congestion
occurring in the distal arm at the circular compression; he tried to
avoid this difficulty by firmly fastening the sphygmugraph. Yet every
one who is accustomed to the use of the sphygmograph, and Sani
himself in the first place, knows how much caution is required
when making conclusions from the intensity of the pulsation recorded
sphygmographically. A slight displacement of the sphygmograph, a
slight increase of the pressure on the spring by swelling of the arm
(veinous congestion) and so many trifles more can entirely change
the form and the intensity of the sphygmographic pulse.
Therefore this — though an objective — method does not seem to
us to be an improvement with regard to the purely palpatory method.
About the so-called sensatorial method, by which the patient himself
indicates when he feels that the pulsations in his artery begin and
cease (beginning and end of the great oscillations) we need not say
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much It is only to be applied to intelligent patients, and introduces
the subjectivity of the patient instead of that of the investigator,
which is at least as bad, and causes by exertion of the attention an
increase of the blood-pressure.
The auscultatory method (Kororkow) by which, distal from the
armilet, an artery-tone is heard to become louder or softer in accord-
ance with the different pressures prevailing in the armlet, so that
in this way indications must be obtained for the determination of
the MBp and the mp is of course connected with the same draw-
back of subjectivity.
The same objections hold for Exrer’s method, who feels the maximal
oscillations and the disappearance of the pulse at the artery imme-
(ately below the lower edge of the armlet.
None of these methods could therefore satisfy von RECKLINGHAUSEN,
and he tried to find another.
He fills the armlet with water and graphically registers the fluct-
uations in it by a Hirrane tonograpb. On theoretic grounds he
admits that if the pressure in the armlet = the pressure in the
artery, the arterial wall moves freely, and the amplitude of the
pulse-wave is correctly recorded by the tonograph. And at the same
time he admits that, as at that moment the pressure in the armlet
= the pressure in the artery, the height of the pulse-wave is conse-
quently correctly recorded. Then he divides the pulse-curve into
different parts and admits that where a definite part is recorded as
greatest, its height is also correctly recorded. From a ‘“Treppencurve”
obtained in this way, he construes then an absolute sphygmogram.
Sanit has given a sharp criticism of this long-winded method,
which can be read in the D. Arch. f. Klin. Med. Bd. LXXX 1904,
p. 493, and which we are not going to repeat in extenso. He proves
that the friction during the passage of the pulse-wave under the
— broad — armlet and other factors are as many sources of errors.
In his last publication von RecKLINGHAUSUN maintains his method,
especially because it gives the same figures for the pressure of the
blood as the other methods (Beihefte zur Med. Klinik, Hft. 8, 1910).
He forgets, however, that just those other methods are not sufficiently
reliable on account of their subjectivity.
However it may be, great discrepancy still prevails with regard
to the problem of determining the pressure of the blood in man.
All methods give us a somewhat unsatisfactory feeling. Moreover
von ReckLineHausEN’s method is complicated, his apparatus is expen-
sive and his reading of the curves not in every respect without
objection.
78
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1186 )
It seems that with all methods, even with von RuecklinGnavusen’s
arbitrariness of the investigator is by no means excluded,
It was on purpose that hitherto we did not mention another diffi-
culty ie. the factor of the arterial wail.
Usually this factor is entirely left out of account, because it is
supposed to be = 0. This opinion is chiefly founded on investigations
made on postmortem arterial walls. Yet in drawing conclusions from
these investigations one should be very careful. It seems that a short
(ime after death the contraction of the arterial wall and at the same
time its rigidity considerably increase. Investigations made at that
period have no value for our object.
On the contrary it seems that the arterial wall is very soft and
compressible immediately after death, but who will decide if these
are not already symptoms of mortification ?
And even — who shall decide, if sot also in the arterial wall of
the living animal, whose artery was laid bare, the contraction and
consequently the compressibility has not changed on account of the
operation ?
And if the arterial wall may not be neglected, the determinations
of the pressure of the blood, as they have hitherto been performed,
become still less reliable. Is then at the determination of the blood
pressure according to the method of the greatest oscillations, this
arterial wall included in the determined blood-pressure, or not? Or
is perhaps the factor of the arterial wall the cause of the different
views that are current about the question: which of the great oscil-
lations are registered at the very moment when the mp prevails
in the armlet ?
With the determinations of the blood-pressure, at all events of the
maximal one, according to the palpatory method, the arterial wall is
almost certainly included.
Could perhaps the comparison of the two methods give us some
information about the arterial wall? In our opinion the subjectivity
of the methods is too great.
After all that has been said, we cannot be surprised that there is
such a great disagreement among investigators concerning the valuation
of the influence of the arterial wall. So Lronarp Hitt found the
carotid of a child collapsed by a pressure of 2 mJ/Hq; HprrincHam
and Womack found in their determinations of the compressibility of
different arteries, 4—18 mMHq, in two cases even 30—34 mM Hq.
Let us for a moment suppose that the factor of the arterial wall
is greater than O, then we can easily understand, why the beginning
of the great oscillations, and the greatest oscillations do not oecur
(sia)
at the same pressure of the armlet. Von R&ckLiInGHAUSEN explains
this by admitting purely theoretically, that the artery is not com-
pressed long enough to be perfectly closed, if the pressure in the
armlet is just a little more than the diastolic pressure; and that the
following systolic pulse-wave comes already before the artery is
perfectly closed. Consequently only at a higher pressure in the armlet
the oscillations will obtain the maximal amplitude.
It may however be asserted that if in the armlet a pressure prevails
somewhat higher than diastolic pressure, the artery is only slightly
pressed down on account of the resistance offered by the arterial
wall, and that not until the pressure in the armlet has increased
with the amount required to overcome that resistance, the artery is
entirely pressed down during the diastole of the heart, and of course
the oscillations have not reached the maximal amplitude before that
moment.
From this consideration it might follow that the difference of the
iwo pressures corresponding to the greatest oscillations and_ the
beginning of the great oscillations represents the resistance of the
arterial wall.
It may easily be granted that this is likewise a purely theoretical
reasoning: yet it explains the gradual increase of the amplitude of
the oscillations at an increase of the pressure in the armlet in a
more plausible way than the reasoning of vON RECKLINGHAUSEN.
Judging from the objection brought forward above there was great
need of discovering a method which, besides enabling to make a reliable
determination of J/Bp and m&p, permitted a valuation of the influence
that the resistance of the arterial wall had on these determinations.
Moreover it seemed desirable to make the method as objective as
possible, free from all subjectivity both of the investigator and of
the patient. And as graphical methods as a rule satisfy this condition
of objectivity best, it was evident that, at least for projecting and
elaborating the method, graphical registration should be used.
After many researches we have at last come to the conclusion
that we might publish the following method, expecting that by careful
investigation, also by others, it will prove to answer the requirements
mentioned above.
Il. DescrietioN OF THE METHOD.
After all this method is very simple. /é consists in neither observing
palpatory, nor recording sphygmographically, nor overhearing stethos-
eee
13*
( 1188 )
copally, what oceurs distal from the compressing crmlet, but in
registering it plethysmographically.
We take a sufficiently large comprising the whoie forearm and
the hand of the patient — firmly closed, not leaky plethysmograph.
A simple tin plethysmograph after the model of Mosso is perfectly
satisfactory for our purpose. The band of this plethysmograph must
be made of thick not over-elastic rubber, and wide enough to surround ,
a normal upper-arm with a slight tension. Care should be taken
that the band is long enough to cover the upper-arm to the extent
of e.g. 10 em. In the front part of the plethysmograph the tube is
soldered that the rubber tube conducting to the Marty-tambour fits ;
the membrane-displacements of this little tambour are registered in
the usual way on a revolving drum. The whole plethysmographical
apparatus is filled with air.
If the plethysmograph is applied in this way, the fluctuations of
volume of the arm, which are caused by pulsation and by respiration
are recorded on the revolving drum covered by smoked paper. We
must directly call the attention to the fact that all motions must of
course be avoided by the patient, as these are also immediately
followed by fluctuations of volume of the enclosed arm.
Psychical iufluences-do not at all or hardly disturb our investigations,
as will appear afterwards.
Now the armiet that is to compress the arm circularly is applied
round the rubber band) of the plethysmograph. This armlet is placed
in such a way that it surrounds only that part of the plethysmograph-
band that closely encircles the upper-arm, so that the lower edge
of the armlet lies at some distance above the part of the plethys-
mograph-band which bends from the arm to the border of the plethys-
mograph. In order to be sure of this it is advisable to encircle the
arm between the border of the plethysmograph and the armlet
slightly with a rubber tube (part of a stomach-sound e.g.) that is
fastened in that situation. This has likewise the advantage that the
part of the plethysmograph-band that has been left uncovered between
the tin plethysmograph and the compression-armlet is tightly strained
and by turning aside cannot make the curve miscarry. Fixation
of the plethysmograph can often prove useful.
For a compression-armlet we used the armlet with two chambers
of Wysavw, connected with a mercury-manometer. The proximal
chamber of that armlet must receive the so-called “Rand-Pulsationen”
1)-In order to avoid misunderstandings, we shall always call the rubber band
of the plethysmograph: band, the hollow compression-armlet always: armlet.
_ —
( 1189 )
whilst only the distal chamber is connected with the registering-
apparatus (according to ERLANGER’s principle) and registers the pulsations
of the encircled artery. With our method we have consequently, at
the same time, registered the curve that depends on the principle
o: the greatest oscillations. Occasionally we have used the narrow
compression-armlet of Riva-Roccr and then we have not registered
the oscillations.
We wrote consequently above each other: I the curve according
to the oscillatory method, 2 the curve of the plethysmograph. Only
the pressure prevailing every time in the armlet was read on the
manometer and always immediately registered in the curve.
In order to obtain fine curves, it is advisable to make the patient
hold his’ breath for a few seconds every time when, at a definite
pressure, both curves are registered. Otherwise the respiration can
always be more or less distinctly observed in the plethysmographic
eurve, which, though not rendering the reading impossible, causes
at all events some difficulty. It is interesting, that even during a
pressure in the compression-armlet far above the J/6p when certainly
all the veins and arteries are tightly compressed, the respiration remains
always distinctly visible in the curve. Even then every inspiration
lowers the curve a little, every exspiration raises it, and this is the
case just as well when compression-armlet and plethysmograph-
band are both appled round the upper-arm, as when the former is
applied round the upper-arm and the latter round the forearm, and
consequently the influence of the one on the other is entirely excluded.
This influence of respiration is even to be observed, if the patient’s
whole arm is tightly held by an assistant. We hope we shall be
able to give an explanation of this phenomenon in a subsequent
investigation.
At present the communication suffices that in case we wish to obtain
fine curves, the patient has to hold his breath each time. However,
the moments, that interest us, can for the vest likewise be read with
great accuracy with ordinary calm respiration. ,
How strongly the plethysmograph-band and the compression armlet
encircle the arm is of little consequence, if only one takes care to
remain below the mp. This is of cowrse easy to do, and is moreover
quite usual. We did not observe a single exception in this respect,
not even with very thick arms. And if in the beginning we remain
below that pressure, the gradually more and more inflated compression-
armlet will exceed the pressure of the plethysmograph-band ; conse-
quently this is no longer of any account. There is, however, no
objection to taking a wide band, which does not even press a thick
( 1190 )
arm, as the compression-armlet will bring about the stopping up of
the plethysmographic apparatus towards the upper-arm.
After this introduction we may proceed to the experiment :
For this purpose we quickly increase the pressure in the com-.
pression-armlet, till it certainly surpasses the J/5p. This must be
done quickly in order to prevent the veins of the arm from filling
abundantly. At a slow augmentation of the pressure in the armlet
this would oceur, as the veins are certainly sooner obliterated than
the arteries. Therefore we must proceed rather quickly. Then the
arteries shut themselves soon after the veins. 5ome veinous congestion
certainly oceurs but this is no impediment. If the pressure in the
armlet has reached a height that doubtlessly exceeds the J/Bp in
the artery, then we let simply the surplus pressure, occasioned by
the veinous dilation of the arm, escape through a valve in the tube
of the plethysmographic apparatus, aad consequently the curve begins,
whilst in the plethysmograph atmospheric pressure prevails. Then the
valve is carefully closed.
The further course of the experiment can best be demonstrated
by following the curves. All curves have a typical form and are
very easily registered. After some practice failures need not occur.
Let us take as an instance the curve obtained from J. P. V. (a normal
individual, 26 years 17. I. 1911 Fig. I).
We began with a pressure in the armlet of Wysauw of 160 mm.
He. and made the drum revolve a few seconds. Neither in the
plethysmographic curve, nor in the curve of the armlet itself any
pulsation is seen. Consequently a pressure was reached that certainly
surpassed the J/5p. After having stopped the drum, we lowered the
pressure to 150 mm. Hg. If we made the drum then revolve again
for a few seconds we did not see any pulsations either,
In this way we constantly lowered the pressure a few mm. Hg.
and registered the curves.
At 145 mm. Hg a feeble pulsation is observed in the curve of
Wysacw’s armlet, in the plethysmographic curve we do not yet
discover anything. We see the same at 140 mm. Hg. Now one must
remark that the plethysmographic curves at 160, 150, 145 and
140 mm. Hg are registered nearly all at the same level on the drum.
A great change however takes place at 135 mm. Hg. Suddenly
the plethysmographic curve goes upward. This means consequently
that blood penetrates into the arm. For ascension of the curve means
that the membrane of the Marey-tambour is lifted up. This means
increase of the pressure of the air in the plethysmographic apparatus,
and this must be the consequence of swelling of the arm. And the
a
(1191 )
only cause why the arms swells can be that under the Wysauw
armlet blood penetrates into the arm. As a proof for the accuracy
of this reasoning must be admitted the plethysmographic curve
registered at this pressure, in which a slight pulsation — for the
first time — can be observed.
Here we have doubtless before us: the moment of the MBp. That
is to say that in that J/5p of course the factor of the arterial wall
is included. For the latter will be of use to open the artery.
At this moment the oscillatory curve shows nothing particular
that could not be observed at a former pressure.
Now we wait quietly till the lever of the Marry-tambour does not
rise any longer. This takes some time. If at last the lever rises no
more, we see as a rule that it continues in the position it has
reached. We shall afterwards revert to exceptions. In case of doubt
we register a second, third ete. curve at the same pressure. If then
really the lever remains at the same height, we know of course
that the arm does not increase any more in volume, and consequently
the slight pulse-wave that passes under the compression-armlet is no
longer able to increase the volume of the arm.
Then we lower the pressure with e.g. 5 mm. Hg. (in our case
to 180 mm.).
The curve again moves upward and the pulsation becomes more
distinct. Both occurrences are proofs that the artery opens more
widely. No change is to be seen as yet in the oscillatory curve.
Again we wait calmly fill the end of the upward move, register
eventually another curve (comp. the example).
Now we lower the pressure to 127 mm. He and after a few
moments we see the plethysmographic curve go down rather rapidly.
What has happened ?
During the pressures of 135 and 150 mm. He blood continued to
flow into the arm because the arteries were open and the veins still
closed. This blood flowed through the arteries, through the capillaries
towards the veins, and would have left the arm again, if in the
veins it had not been arrested by the compression-armlet and kept
back there. Consequently the volume of blood in the arm increased,
and the plethysmographic curve rose, and continued to rise of course
till the pressures distal and proximal of Wysauw’s armlet are equally
balanced.
Now we may consider the arteries 4- capillaries ++ veins as a system
of communicating vessels, and certainly so, if we work slowly. As
long as the pressure in the veins is lower than that in the arteries,
blood will flow from the arteries into the veins, and consequently
( 1192 )
the volume of the arm will increase as long as the veins are still
tightly compressed. This will continue till the pressure in the veins
has become equal to that in the arteries. Consequently, if only we
work slowly enough, the arterial blood-pressure will at last prevail
in the veins, i.e. the pressure of the blood-column itself, whilst the
influence of the arterial wall is of course excluded.
Not before this pressure in the veins, which must consequently
be inferior to arterial pressure -++ arterial wall, and is supported
both by the parietes of the veins and the surrounding tissues, sur-
passes the pressure in the compression-armlet, the blood under that
armlet will be able to flow again from the veins to the heart. But
at that moment the volume of the arm will decrease again, for the
fall in the veins distal and proximal to the armlet is at that moment
enormous.
Now the volume of the arm diminishes in our case at a pressure
of 127 mm.Hg. The downward move of the vegistered curve proves
it likewise.
As we may neglect the parietes of the veins as factor, this pres-
sure is consequently the real pressure of the blood without the factor
of the arterial wall.
A fortiori we may regard the arteries + capillaries + veins as
a system of communicating vessels, if we take into account LEonarD
Hiti’s words: ‘that there are wider channels connecting the arteries
and veins through which the pressure is transmitted to the veins.
The existence of such wide channels is recognised by histologists.”
(Further advances in physiology, 1909, p. 148).
In the beginning we simply waited till the lever of the Marry-
tambour did not move upward any longer. Then we diminished the
pressure. In this way we obtained as factor for the arterial wall
with normal persons about 15 mm.He. (40 observations).
Then Lronarp Hitt and Marti Frack’s article in the Journal of
Physiology vol. XXX VIII came to our hand. In order to determine
the exactitude of the palpatory method they proceed from the same
idea as we, viz. that in the end the same pressure prevails in the
veins as in the arteries, if the latter are open, and the former tightly
compressed. Their experiment is best cited in their own words:
“We place one armlet round the brachial artery, and another
narrower one round the forearm of the same arm — each connected
with a manometer. We find the obliteration pressure with the first
armlet. Suppose it is 150 mm. Hg. We lower the pressure in this
armlet to say 145 mm. Hg. so that arterial blood ean get through
into the limb, but cannot get out of the veins of the limb until
(1193 )
the pressure in the veins rises above 145 mm. He. Allowing time
for the veins to fill, we then measure the pressure in one of the
superficial veins and find that it does finally reach this pressure
We raise the pressure in the second armlet, observe the pressure
at the moment when the vein fills from below. One of us watches
the vein and signals the moment of filling, the other reads the
manometer. We repeat the observation several times. If we find
the pressure in the vein reaches 145 mm. Hg, we know that the
obliteration pressure was correct within 5 mm. Hg. To carry out
this method a vein must be chosen which does not fill from above
or at any rate quickly. With such high pressures in the veins the
valves leak, and this makes quick working necessary. In cases of
high pressure it is necessary to give a rest between each test as
the maintenance of the first armlet at a pressure close to the obli-
teration pressure is rather painful.
From the above observations we conclude that the obliteration
method of measuring the arterial pressure is correct within 5 mm.
Hg, even in cases where the arterial wall is markedly changed from
pathological causes.
One sees what startling similarity there is between this metiod
and ours, with regard to the point of issue. And at the same time
one sees that Lronarp Hint, and Martin Fiack’s experiment has
proved that — when working in this manner — one may consider
arteries + capillaries +- veins as a system of communicating vessels.
Though Hini’s determination of the “obliteration pressure” is made
after the palpatory method and consequently has the incorrectnesses
of subjectivity, described in our first chapter; and though, as one
can read in the description, the determination of the pressure in the
veins is connected with some difficulties, yet there was in this pu-
blication an incitation for us to make a new series of experiments,
in which we proceeded still slower. Though we shall afterwards
revert to the general conclusions, yet we can now already state that
in the beginning the factor of the arterial wall was most likely
valued too high by us, but at the same time that the arterial wall
may not entirely be neglected.
To return to our case we may thus give as figures there:
MBp + A between 140 and 1385 = 137 mm. Hg.
MBp between 130 and 127 = 128 mm. Hg.
Consequently : Av == | 9mm. Hg:
That the fall of the plethysmographic curve is in reality caused
by the veinous blood being pressed from below the compression-armlet
to the heart appears from a peculiar behaviour of the oscillatory
( 1194 )
curve, as it can often be seen and controlled at the manometer. If
we look at curve Il (D. M., normal individual, 31 years, 6 L1911)
we see the oscillatory curve rise at LOT mm. Hg. This is oecasioned
by the veins beginning to press the blood under the compression-
armlet, so that the pressure in it increases, for the volume of the
arm at the place of compression augments. We see consequently the
mercury in the manometer rise a few mm. And if now we lower
the pressure in the armlet, the passage under it is foreed by the
veinous blood, and the oscillatory curve goes down again (in our
case at 106 mm. He).
It is clear that, if Pacnon is right, namely that under the broad
compression-armlet the pulse-wave can be annihilated at a certain
pressure, and yet the blood continue to ooze under the armlet, (comp.
p. 1184) that in that case the palpatory method for dertermining the
MBp + Aw fails; our method however does not, as the oozing of
the blood will likewise swell the arm and consequently make the
plethysmographic curve rise.
After these elucidations it appears to us that our method enables
us to determine the Wp + Aw exactly and to estimate the factor
of the Av.
One remark must still be made. We found like Hiti and Frack
that at high bloodpressure — but only then — the slow operation
could become painful for the patient. And as it is admitted that pain
can raise the bloodpressure it might be possible that our determination
of the Ar consequently became incorrect (too small). This objection
also holds for Hiri and Frack’s experiments. In such cases it is
therefore necessary to raise the pressure again quickly to just a little
above the J/Sp + Aw that has been determined before, and to see
if the pulsation has disappeared. If not, then it is necessary to deter-
mine the pressure at which the plethysmographie pulse disappears
again. This method however gives less beautiful results. It seems
that occasionally at very high Ap, the Bp rises a few mm. during
the slow phase of the experiment. At lower 4p the pain is not felt.
After having noted a few times more ihe curve at lower pressure
(120, 115, 110mm.) in order to state that now really, when lowering
the pressure,a gradual fall takes place, we open, in order to deter-
mine the mp, the valve of the plethysmographic apparatus for a
short moment, and let the surplus pressure escape from it. We repeat
this at every further diminution of pressure in order to have in this
way the following curves registered at the same level. This is neces-
sary for the following reason.
ar
( 1195 )
We had hoped tbat at the moment of the mp something similar
would occur in the arteries and veins to what is observed at the
moment of the J/6p. Sometimes we suppose that from the rise and
fall of the curve we can read something about the mbp and the
Aw, but it appeared that this was not regularly the case. We made
several experiments, but continued to be unsuccessful. Therefore we
have been obliged to desist from determining the mp and the
mBp + Aw in this way. We only succeeded — by another method —
to determine the mBp + Aw from the plethysmographic curve. From
what we know already about the Aw, we can, however, easily
calculate the mbp alone.
In order to determine the mbp + Aw we act as follows:
After having closed the valve again we recorded once more the
curve at 110 mm. Hg. Then every time the pressure was lowered
5 mm. Hg, the valve of the plethysmograph was opened, shut again
and the curve recorded.
After fixation of the whole curve, the amplitude of the pulsation
was measured at every observed pressure. Now it appeared that this
amplitude gradually increased till, beginning from a definite pressure,
it became constaut, and only decreased again a little at very low
pressure (because the armlet at that pressure fitted less tightly round
the arm).
We need not say that, as we were now trying to gather information
from the amplitude of the pulse-wave, it should be registered every
where at the same level.
In our opinion consequently the pressure at which, operating in
this way, we saw the pulsation show for the first time the maximal
amplitude, is the mbp —+- Aw.
To understand this we had best reverse our reasoning — as if
from O we constantly raised the pressure.
Thereby we must keep in view that the pulse-curve of the plethys-
mograph is a volume-curve.
If now the pressure in the compression-armlet is lower than the
( 1196 )
mBp, then at each heart-systole the whole volume of blood will still
pass under it, and the plethysmograph-curve shows us the changes
of volume that result from it.
This will also take place when the m Bp (+- Av) has just been reached.
When, however, the pressure becomes a little higher than that
mBp—+ Aw, then the artery remains shut during part of the pulsation.
Instead of the entire volume fed only b'cd' passes under the
armlet during each heart-systole. A part is constantly arrested by the
pressure, the volume of blood passing under the armlet beeomes
smaller and from that moment the volume-curve of the plethysmo-
graph consequently becomes smaller. This moment lies thus a little
above the mBp + Ai, and the moment before was thembp + Av.
Sometimes it can at the same time distinctly be seen that, if the
pressure reaches just a little above the mBp + Aw, not only the
pulse-wave of the plethysmograph becomes smaller, but that also a
diastolic pause can be observed in it. For during the time d’—d"
no blood is thrown into the arm. Very often, at all events the latter
part of the pulse-wave has become much more horizontal. This
occurrence consequently, when it presents itself, furnishes a good
control for the diminution of the pulsation.
In our curve | the diastolic pause is not visible but the diminution
of the pulse at 80 mm. Hg can be distinctly observed. In curve III
on the contrary the diastolic pause at 85 and especially at 90 mm. Hg
can be very well distinguished
In our example curve | is consequently :
mBp + Aw == oem ie
Aw (comp. above) was 9 mm. Hg
Thus mbp = 66 mm. Hg.
The phenomena regarding the amplitude of the plethysmographic
pulse oceur, whether the manometer is connected with the armlet
or whether it is pinched off, and consequently do not depend upon
the mercury-fluctuations. With the simultaneous registration of the
two curves it is, however, peculiar, that the last great pulse-waves
of the plethysmograph ‘and the greatest oscillations usually show
themselves at the same pressure, which agrees entirely with our views
concerning the signification of the greatest oscillations (comp. Chapter I).
If we closely examine the oscillatory curve, we see how difficult
it is to find out with certainty the beginning of the oscillations that
are to indicate the J/Bp. And we see at the same time, how if is
almost impossible to determine beginning avd end of the great oscil-
lations. And according to our experience this is often the case. We
( 1197 )
have already said that the oscillation-curves do not teach us anything
about the Av.
Before continuing we must call the attention to the fact that one
should take care not to be deceived by the expansion of the air in
the plethysmograph by warmth. Whoever is conversant with the
method sees immediately, what is the consequence of the air in the
plethysmograph becoming gradually warm, and what must be attri-
buted to the pulse-wave entering into the arm. Moreover one can
easily introduce into the plethysmograph air that has been previously
warmed, or wait till the air in it has obtained a constant degree of
warmth. The latter method takes time, but this is rather an advan-
tage than a disadvantage. Every first determination of the 4p what-
ever instrument may be used, gives, on account of psychical influ-
ences, too high figures. and only the subsequent determinations, when
the patient is no longer afraid of the instrument give constant figures.
Consequently there is no objection to making a first determination
whilst the air is becoming warm, by which the patient overcomes
his fear of the instrument and the operator gets orientated.
It is with p-apparatuses as with thermometers. The so-called
thermometers “a Ja minute” must just as well lie 10 minutes in the
axilla as the ordinary ones, because the axilla has not assumed the
warmth of the body before that time. So neither quick determinations
of the Ap can be made, because the patient must first overcome
his fear of the instrument. If once the patient is familiar with the
instrument then, the next day or a following time, the first deter-
mination is more reliable.
Ill. ResuL_ts OBTAINED.
Up till now we made on various persons 172 determinations in.
all, 40 of these were taken at nephritis, 4 at insufficientia aortae, 3
at arterio-sclerosis, 1 at the disease of Stokws—ADAm, and the rest
at tub. pulm, anaemia, arthritis, nervosism and normal individuals.
It is impossible and unnecessary to give all these figures here. We
shall only select a few at random.
So of our example the figures were :
1. J. P.V. 27 years (norm.) MBp + Aw. 155 140 ..137,- 137
MBp 145 129 128 105
Aw. 10 11 9 12
mBp-+ Aw. 75 75. %5- 73
The third row of figures belongs then to curve I.
( 1198 )
From the patient, from whom curve IL was obtained, afew more
complete eurves were taken.
2. PD. M. 31 years (norm). MBp-+ Aw. 4115 112
MBp 106 106
Aw. 9 6
mBp-+ Aw. 80 80
From the patient of curve IIL (5 row):
3. H.v. L. 27 years. (norm.) MBp + Aw. 115 5
MBp 108 117 110 108 is
AWix ae roe 0
mBp + Aw. 75
From the female patient of curve IV (3"4 row) :
4. Mrs. Sch. 70 years (art.scler.). MBp + Aw. 154 147 145
MBp — 138 140
Aw. =— 9 5
mBp+ Aw. 100 95 90
And finally from the patient of curve V (8" row):
5. J. v. N. 24 years (neph. chr.) MBp + Aw. 147 148 152
MBp 137 139 PS hsy
Aw. 10 SG) il
mBp + Aw. 110 110 100
We found the following averages (with Wysauw’s armlet):
A. Normal 15—20 years 21—40 years 41—60 years over 60 years
MBp+ Aw. 114 194% 132 145
MBp 104 112 125 139
Aw. 10 9 i 6
mBp + Aw. 70 75 76 86
Pulse amplitude 44 46 56 59
B. Nephritis chron.
MBp + Aw. 162
MBp 149
Aw. 15
mbBp + Aw. 104
Pulse amplitude 58
©. Insufyicientia Aortae (Riva-Roccr’s armlet .
MBp + Aw. 157
MBp 140
Aw. 17
mbp + Aw. 70
Pulse amplitude 87
(1a 99")
D. Disease of Stokes- Adam (Wrpavw’s armiet).
MBp + Aw. 197
mbp + Aw. 80
Pulse amplitude ty Ig
A few determinations of fie arterial wall were too great because
the determination was made too quickly. Not taking into account
however these determinations we were struck by the fact, that the
factor found for the arterial wall with the same person, is rather
constant, even with different 1/5). This proves of course strongly
in favour of the method.
Only once in the 172 determinations the determination of the
MBp + Aw is doubiful, most likely on account of the influence of
the expansion of the air in the plethysmograph by warmth. All
other determinations could be read with perfect accuracy.
The determination of the Ap without the Aw requires greater
care and to state this we may not be satisfied with a few deter-
minations.
With normal persons as a rule the J//4p increases with their ages
and so does the mAp, which was not unknown.
The Aw factor does not vary in the same degree. On an average
it is 6—10 mm. Hg. Consequently the mistake is not great, if we
consider for normal people the Ap + Aw determined according
to the obliteration-method as the maximal blood-pressure. And with
our method the latter can be quickly and easily determined, whilst
the determination of the Aw requires time, and is somewhat painful
with high blood-pressure. But it is only so with high blood-pressure.
One of our patients with a maximal blood-pressure of 135 mm. Hg.
did not feel any pain, another with a maximal blood-pressure of
170 mm. Hg. did feel pain.
In general the figures found by us do not deviate from those
which are usually admitted as normal.
It is remarkable that the influence of the Aw that was found with
arteriosclerosis was very slight. Perhaps we may not conclude too
much from our single case. Yet a slight influence of the Aw with
strongly pronounced arteriosclerosis would perhaps not be fully in-
explicable. In such an arterial wall we find besides calcified parts
which undoubtedly offer a greater resistance to the compression than
a normal wall, certainly also degenerated parts of the nature of a
fibrous tissue, the elasticity and resistance of which have diminished.
This view seems to be confirmed by the decrease — though only
in a slight degree — of the Aw with the age.
( 1200 )
The influence of the ctv is offen stronger than normal, for the
observations we made, with chronic nephritis. Nor need this fact
remain unexplained, for we may admit that a contracted artery
hard pulse of the nephritici will offer a greater resistance to the
compression than a normal artery.
It is remarkable that after these observations we found a report
of an article of Janeway (Lancet March 1911) in which this investigator
also comes to the conclusion that with arteriosclerosis the arterial
wall has little influence on the determination of the blood-pressure,
a contracted arterial wall on the contrary has great influence!
To be short, we are convinced that our method procures reliable
information about Ip and mp, and gives an impression of the
factor of the Av.
In order to determine averages of the 4p with normal men of
different ages and with various diseases still more determinations
must be made.
The same is necessary if we wish to compare the results obtained
with the narrow and the broad compression-armlet. Though it seems
io us that higher figures are obtained with the narrow armlet, we
have not yet made a suflicient number of comparative determinations
to express a decided opinion on this head.
Microbiology. — “Lipase produced hy Microbes.” By N. 1. SOHNGEN.
(Communieated by Prof. M. W. Beterinck.)
(Communicated in the meeting of March 25, 1911).
In a previous paper’) a number of fat-splitting bacteria were
described which occur very generally in nature; at the same time
the way was indicated by which these species may be distinguished
from others and how they are brought into pure culture from the
soil, sewage water, milk, or rancid butter.
Among the yeasts and moulds, too, we meet many species that
form lipase. Thus most yeasts contain endo-lipase ; at abundant
nutrition they are able to store up fat in the cell, and can use
it again when less favorable culture conditions occur.
Only a small number of yeast species secrete diffusing lipase ; to
these belong some species often found in milk, among which a
Torula. Fat-splitting yeasts may be obtained from garden soil by
inoculation into a medium of the composition : 100 tap-water, 1 fat,
1) These Proceedings X1ll, p. 667.
(e204)
0,05 KCI, 0,05 NH,Cl, and 2 to 4 drops of phosphorie acid, with
aérobie cultivation at 20°—25° C. The isolation of the fat-splitting
yeasts is then effected by sowing the enlture in which they are
accumulated on yeast-glucose-gelatin with calcium carbonate, solidified
in a culture box on a thin layer of fat. The colonies of the fat-
splitting yeasts are signalised on this medium by their hydrolising
the fat.
Diffusing lipase is much more commonly secreted by moulds than
by yeasts. Fat-splitting moulds can be best isolated from rancid fats.
From the air, also, fat-splitting yeasts and moulds are obtained by
exposing the said medium for some time to the air and subsequently
isolating those organisms which have splitted fat under the colony.
Fat-splitting bacteria, yeasts, and moulds, all secrete a lipase pos-
sessing the same properties as shown by many experiments.
Consequently, although the following researches are for the greater
part carried out with lipase formed by bacteria, the thereby obtained
results hold true as well for the lipase of yeasts and moulds.
Formation of lipase by microbes in culture media
of different composition.
When fat-splitting microbes are cultivated in media of different
composition, it is found that in media wherein they grow, also lipase
is formed.
Thus, B. lipolyticum, Oidium lactis, Torula, Penicillium glaucum,
secrete lipase when cultivated in tap-water to which is added 0,05 °/,
bikaliumphosphate, one of the following carbon sources: glycerine,
glucose, calciumlactate, or natriummalate, ‘and one of the nitrogen
sources: peptone, asparagine, ammoniumcehlorid, or kaliumnitrate.
The nature of the carbon and nitrogen sources is thus of no
consequence for the formation of lipase by micro-organisms which
assimilate them, that is to say, if a carbon or nitrogen source, what,
ever be its composition, is assimilated by a fat-splitting organism,
it will serve for the production of lipase by that organism.
The composition of the medium, however, exerts its influence on
the quantity of secreted lipase.
By a certain number of microbes the greatest quantity of lipase
is secreted when the culture conditions are the most favourable. This
fact can be demonstrated in a simple way by a method with tubes
coated with fat.
Various substances, however, exert a retarding influence on the
secretion of lipase by microbes, namely such compounds as sugars
and alcohols, from which they form acids.
79
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1202 )
Influence of acid and alkali on lipase.
The great influence of acids on the decomposition of fat by lipase
produced by microbes, is most evident when the microbes which
form acid from glucose, such as Penicillium glaucum, Oidium lactis,
GL. lipolyticum a, B. Stutzeri, or B. fluorescens liquefaciens, are
cultivated on brothagar with 5°/, glucose, solidified on a_ thin
layer of fat in a culture box, or in a fatted tube of broth with
5°/, glucose. These microbes do not split fat in the medium by
diffusing lipase; the fat remains quite unaltered. It is true that it
is slightly attacked through direct contact, for example by the mycelium
of moulds, when this has grown through the agar and subsequently
touches the fat, or by bacteria in the tubes when in a layer near
the surface they locally also touch it. The decomposition of the fat
does not, however, take place deeper in the tube and it is always
excluded when there is some distance between the fat and the
organism.
In the accompanying figures A and 6B may be observed the
influence of acid formation and of the presence of acid in a medium
on the action of microbic lipase.
A represents a culture box with broth-gelatin solidified on a
layer of fat.
/ is similar to A but contains broth-gelatin to which 5°/, giucose
has been added.
Qn both media streaks are made only of fat-splitting bacteria, in
the way as indicated in Fig. 1.
In A all the bacteria make fields of splitted fat, as is distinctly
to be seen; this is not the case in B where B. Stutzeri and B.
~~ 8 Stutzerr
s ~~
= &
= > 3
oS} NY Afp|es
= iin S
3 (ip 7
= wu 5
7 pact? 3
B. lipolyticum x
Fig, 1.
( 1208 )
lipolyticum a, which form acid from glucose, do not split. We likewise
observe that the presence of acid also prevents decomposition of the
fat by the lipase produced by the bacteria which do not form acid
from glucose; this is distinctly to be seen by the narrowing of the
fields at the points where the inoculation streaks cross.
It would, however, be erroneous to draw the conclusion that in
cultures where the fat is not decomposed by the formation of acids,
lipase is neither secreted. That this enzyme is indeed present is
proved by neutralising such a culture after addition of an antisep-
ticum; already after some hours a distinct decomposition of the fat
is to be observed; it is not, however, so vigorous as in cultures
where no acid formation has taken place, although the microbes in
cultures with glucose thrive often better than in those without it.
But if calciumearbonate is added to culture media containing glucose,
the acids formed by bacteria are neutralised, the fat is then
decomposed nearly as vigorously as in cultures containing no glucose
and carbonate. These facts may be stated very simply as well with
the help of fatted tubes as by means of plate cultures.
At a certain degree of acidity fat is no more decomposed by the
lipase, which was shown by a series of tubes filled with an increasing
quantity of acid, in this case lactic acid, with a quantity of
a culture of fat splitting microbes. It is found that the decom-
position of the fat decreases as the rate of acid rises, and that it
ceases entirely when the culture liquid is about '/,, N. acid.
This acid-limit for the action of the lipase is the same for the
enzymes of B. Stutzeri, B. lipolyticum a, B. lipolyticum B, and
of Vidium lactis.
The lipase is rendered inactive as well by mineral as by organic
acids, the former act more vigorously on the ferment than the latter,
so that a lipase preparation, inactivated by mineral acids, after
neutralisation is considerably less active than the same preparation
treated with an equal quantity of an organic acid and subsequently
neutralised. It is some time before the splitting power of the
lipase is restored; this depends on the nature and the volume of the
acid used. Whilst, for example, in a culture containing lipase, after
acidification with lactic acid to */,, N. and subsequent neutralisation,
the decomposition of the fat became already visible after one hour’s
cultivation at 37° in a tube of neutralised culture, this lasted 6 hours
when phosphoric acid of the same concentration had been used, the
same culture conditions being observed.
19*
( 1204 )
Determination of the influence of acid and alkali on
fat-splitting by microbic lipase.
The intluence of acid and alkali on fat-splitting by this lipase was
ascertained as follows.
Ten experiment tubes were filled with 15 c.c. of a neutral
thymol-containing culture of lipolytic bacteria, 10 ¢.c. of a 10°/, fat
emulsion in agar, and into the tubes from 1 to 10 were introduced
respectively from 2 to 24 drops of a concentrated lactic acid solution
in water, so that each contained respectively from 1 to 12 ce.
1/05) Ni acid:
A second series of tubes treated in the same way, contained
instead of lactic acid pene oe so that from 1 to 10 they
contained respectively 1.8 to c.c. */,, N ammonium-carbonate.
After 8 hours at 37° C. ae were quickly cooled to 7° C. and
titrated. For the neutralisation of a 10°/, fat emulsion in agar 0.45
1/
/io
The results of these experiments are united in the following tables.
Cc N acid is required.
Injluence on fat-splitting by microbie lipase.
1 2 3
a
cc. '/y9 N Lactic acid | 0 4 | 5 | 6 | 8 [10 12
|
|
after 8 hours at 37° Cc. 0.8 8 | 1-5), 2.3 | ot) Zirh |W bayeKavel |) Ziasy | tS)otoy al 3155
Quantity of lactic acid | 1 95' 0.95 0.75] 0.55) 0.45] 0.15) 0.05) — | — | —
formed in c.c. !/j9 N. | |
Fat-splitting by Ammoniumearbonate.
c.c. yo N Amm. carb. | 0 ae 18 | 3.6 | 7.2 10.8 14.4 |18
| |
c.c. 1/}9 N acid used eiiier sll } BEN GT
Ss nours at 37° C ne * Waviay) alarA | a bere 4) o 2.10
fatty acid formed. | 0 | 0.40] 0.30] 0.75) 0.95] 1.30] 4.65
Injluence of Ammoniumcarbonate on microbie lipase.
c.c. Vig N acid formed. | 1.25) 1.55] 2.05 2.95} 3.15] 3.75) 3.90
Fatty acid secreted |
| |
|
|
by 0. 10 0.30] 0.75] 0.95] 1. 4 4.65
action of Amm. carb. |
|
Fatty acid formed by h
the action of lipase in | 1.25) 1.45
c.c. 14o N |
|
AD) Qos RADI Qe OS
These experiments prove that in a medium with a lactic acid
concentration of about ‘/,, N no more fat-splitting by the lipase
takes place. The action of the lipase on fat is much favoured by
( 1205 )
the presence of alkali, in this case ammoniumearbonate, and it is
most effective when the medium titrates about */,, N alkali.
It is obvious from the above tables that the action of the lipase
depends on the concentration of the hydrogen and of the hydroxylions,
the former exerting a retarding, the latter an accelerating influence.
From these observations it follows that rancidity of dairy products
can only then be caused by lipase when the acid degree of these
products is below ‘/,, N. This will be the case when the lactic
acid in butter or cheese, which at first exceeds by far the said
concentration, has Jowered to ‘/,, N, through the action of alkali-
producing bacteria and moulds; they neutralise and oxidise the
present acid, whilst besides, by the formation of calciumcarbonate
by the oxidation of calciumlactate, acid is also neutralised.
Injluence of various compounds on the fat-splitting by
microbic lipase.
It was found of importance to consider in how far other com-
pounds than acids and bases act on fat-splitting by lipase. For
these experiments it is desirable to work with a lipase prepar-
ation, which, besides the enzyme, contains no or only extremely
small quantities of compounds that might act on the splitting-process.
Such a preparation is satisfactorily obtained by dialysis of the
medium whereon the lipase-microbe has grown or by precipitation
of the enzyme from it.
Dialysis of the microbie culture proceeds very slowly, so that it
must be continued some weeks, when parchment paper dialysators
are used, before the dialisable compounds are sufficiently diluted to
make the experiments succeed.
The results obtained with such a lipase preparation are to my
opinion not quite trustworthy as during the long time of the
dialysis number of processes may go on in the complex culture
liquid. By means of greased tubes, however, it could be stated that
the fat-splitting power of the culture decreases during the dialysis,
the dialysate containing no lipase or only very small quantities.
When the dialysate is again added to the dialised culture, the fat-
splitting power of the mixture is greater than that of the culture to
which as great a volume of water has been added as in the
previous case c.c. dialysate; it was also found that slight quantities
of calcium and magnesium salts act favourably on the decomposition.
It is possible in a very short time to procure a microbic-lipase
preparation, quite answering the said requirements and which
( 1206 )
enables, moreover, auxanographically to observe the influence of
various compounds on fat-splitting, namely by dialysis of a solid
medium.
This is effected in the following way :
The surface of a broth-agar plate in a glass box is rubbed with
a culture of fat-splitting microbes and allowed to stand about 8 days
at + 25° C. In that time the bacteria have grown and produced
lipase which is diffused in the agar. Now the bacteria are washed
off the agar with water containing thymol, whereupon the agar is
removed from the box and put into a vessel of distilled water. If
now during the first 24 hours the water is a few times refreshed,
the agar contains only very small quantities of dialisable compounds
after 36 hours whilst of the slowly diffusing lipase a_ sufficient
amount for the experiments remains behind.
When this agar is put on a fat-layer in a culture box the fat is
only very feebl* decomposed over the whole surface; on the other
hand, compounds brought on the agar and favouring the decompo-
sition of the fat produce a white field.
In this way it was stated that the following compounds favour
very much the decomposition of fat by lipase: calciumsulphate,
ealciumehlorid, magnesiumehlorid, natriumbicarbonate, ammonium-
chlorid, ammoniumsulphate, trimethylamine, natriumglycocholate,
particularly calcium- and magnesiumsalts, natrium glycocholate and
trimethylamine; whilst kalium, natriuin, ferric and manganese salts
exert less influence. In general it may be observed that small quan-
tities of electrolytes favour the fat-splitting by lipase. In the same
way it was stated that methyl-, aethyl- and amylalcohol retard the
process, sugars and glycerine being of no influence.
Analogous results were obtained by experiments with lipase precipi-
tated from a microbie culture by means of alcohol.
From these facts follows that lipase produced by microbes presents
a great similarity to liver- and pancreatic lipase.
The investigations of Porrevix, Kanitz, Henet, LorvenHart and
Maenus have shown that calcium ions and natrium glycocholate are
very favourable to the process of fat-splitting. The fat-splitting power
of liver extract diminishes by dialysis whilst substitution of the
dialysate to the dialised extract again gives an active lipase. As
co-enzyme natrium glycocholate may be substituted instead of the
dialysate, with the same result.
By means of pancreatic lipase Porrrvin succeeded to prepare fat
synthetically in a biochemical way; we shall see that also with the
help of microbic lipase fat is formed from a fatty acid and glycerine.
>
( 1207 )
Acid-lipases.
From the researches treated in the beginning of this paper about
the influence of acids on the action of lipase it might already be
concluded, that lipase forms a labile compound with acids, which is
easily decomposed by alkalis. The results of the following experiments
will show this still more clearly, besides they will expose some
properties of these compounds,
The diffusion of acid-lipase and its decomposition by neutralisation
we can demonstrate as follows.
The bottom of a glass box is coated with a thin layer of fat and
on it are consecutively poured three layers; broth-gelatin with
4°/, glucose, broth-gelatin with 4°/, glucose and calcium carbonate,
and again broth-gelatin with 4°/, glucose only.
If now we bring on this medium fat-splitting bacteria which form
acid from glucose, acid-lipase, which does not decompose fat, as we
have demonstrated, diffuses through the upper layer of broth-gelatin
glucose; the acid is subsequently neutralised in the carbonate layer
and the lipase diffusing through the second broth-gelatin-glucose layer
reaches and splits the fat.
A compound of lipase and higher fatty acids is, in opposition to
the above named acid-lipase, insoluble, it does not diffuse through the
culture medium.
This can be shown as follows.
On broth-gelatin, solidified on a layer of fat, a thin layer of finely
divided fatty acid is placed, in the same way as a layer of calcium-
carbonate in the former experiment. :
If we cultivate on this culture plate fat-splitting micro-organisms
the said lipase diffuses in the gelatin and is fixed in the fatty-acid
layer. The layer of fat at the bottom of the box remains unaltered.
I have sometimes left such cultures for more than a month at
+ 22° without any decomposition being visible, whilst through a
gelatin layer of the same thickness as the above, +3 mm., a very
obvious decomposition of the fat by the diffusing lipase was observed
already after 4 days’ cultivation.
Thus, although lipase does not diffuse through the layer of fatty
acid, it does do so in the form of acid-lipase. Moreover it is possible
to convert the lipase from the insoluble fatty-acid compound into a
diffusing acid-lipase by means of mineral or organic acids, such as
lactic acid and butyric acid.
These two properties of the lipase can be demonstrated by a
combination of both the foregoing media. Starting from the bottom
( 1208 )
the suecession is then: a fat Jayer, gelatin, gelatin and calcium-
carbonate gelatin, gelatin and fatty acid, gelatin, the gelatin consisting
of broth-gelatin and 5°/, glucose.
On this medium, about 0.5 em. thick, a fat-splitting microbe is
cultivated, which forms acid from glucose, for example 4. ipolyticum a,
and one which does not do so, such as LB. lipolyticum p. After two
weeks’ cultivation fat-splitting is to be observed under L. /ipolyticum a,
whilst under LB. Lipolyticum 8 no splitting is seen. Hence, the acid-
lipase under B. lipolyticum a diffuses through the fatty-acid layer, is
neutralised by the carbonate layer and the further diffusing lipase
decomposes the fat. The lipase of B. (ipolyticum 3 combines with
the fatty acid and diffuses no further.
But if now one of these acids is transported to the place where
B. lipolyticnm 8 has grown, it diffuses through the gelatin, forms
with the lipase which is combined with fatty acid an acid-lipase,
which diffuses and is decomposed in the carbonate layer, the further
diffusing lipase decomposing the fat. It needs no explanation that
lipase is likewise freed when the fatty acid is neutralised by addition
of alkalis so that then also fields of decomposed fat arise.
Hence, microbie lipase behaves in all these experiments as a feeble
alkali forming compounds with acids and again is freed from these
by alkalis.
Influence of oxygen and light on the decomposition of fat by
lipase produced by microbes.
Presence of oxygen and light favour the decomposition of fat by
the action of lipase.
The favourable influence of oxygen on the decomposition of fat
is very simply shown by means of fatted tubes filled with a lipase-
containing gelatin. If some tubes are quite filled with the gelatin
and some others thinly coated with it as is done at the preparation
of roll-eultures, it is found that in the full tubes, where thus no
oxygen can enter, the decomposition of fat proceeds much more
slowly than in the other tubes; still there is more lipase in the
former than in the latter although in the full tubes a more vigorous
decomposition of the fat was to be expected.
It is evident that together with the fat-splitting, oxidation of the
fatty acids takes place.
The special products resulting at the culture method of EyKman
are fatty acids, soaps, oxidation products of fatty acids, and compounds
of these acids with lipase.
( 1209 )
Katalase, produced by the bacteria, plays no part therein, neither
could this be shown for oxidases, these enzymes exerting no action
on the fat-layer in the gelatin.
The favourable influence of light on the decomposition of fat in
presence of lipase may be demonstrated by exposing some fatted
tubes containing lipase gelatin to the light and compare them with
similar tubes kept dark, whilst for control, tubes without lipase were
exposed to the light and others kept out of it.
In the tubes containing gelatine with lipase and exposed to the
light the fat is more strongly affected than in those prevented from it;
the tubes acted upon by light and oxygen are most vigorously attacked.
In the tubes containing gelatin without lipase a slight decomposition
of the fat is observed but it is inferior to that of the tubes with
gelatin and lipase.
Synthesis of fat from glycerine and fatty acid by microbic lipase.
This lipase, as we have seen, splits fat in glycerine and fatty acid
in presence of much water; it is able from glycerine and fatty acid
again to build up fat, if very little water is present.
Some material of 4. lipolyticum @ was used as a lipase preparation.
These bacteria had been cultivated on broth-agar and after 10
days at 30°C. been taken off the agar with a spatule.
In this way about four and a half ¢.e. material had been procured.
This lipase preparation was introduced into a stoppered bottle
with + 50 cc. oleic acid and + 60 e.c. glycerine (S. W. 1.25),
and after addition of a few glass beads for better mixing, the bottle was
filled with glycerine, for which about 25 ¢.c. sufficed.
After the contents of the bottle had been rendered as homogeneous
as possible by vivid shaking, 5 ¢.c. were withdrawn from it and
supplied by 5 ec. glycerine. These 5 c.c. oleic acid + glycerine
titrated 77.2 c.c. '/,, N. caustic soda.
The bottle was now heated to 40° and remained 48 hours
at this temperature, being during that time repeatedly and vividly
shaken.
5 ¢.c. of the contents of the bottle then titrated 56.2 ¢.c. 1/,,
N caustic soda so that about '/, of the oleic acid had disappeared.
The liquid was subsequently poured into two L. of boiling water
and shaken with it, whereupon the oily layer was separated from
it. The oily liquid was washed with hot water and shaken with a
*/,°/o natriumearbonate solution by which the still present oleic
acid dissolved into natriumoleate.
( 1210 )
The remaining liquid was mixed with calciumearbonate, heated
to + 200° C., then sucked off.
After this treatment 11.5 ¢.c. liquid was obtained of an oily
consistency and yellow colour. It reacted neutrally as to litmus and
was soluble in ether, benzene and carbon disulphide.
By heating with alcoholic kali saponification took place. A gram
of this compound uses 163 mG. of KOHL.
The S.W. amounted to 0.938.
Evidently in this synthesis the monoglyceride of oleic acid is
chiefly formed, as follows from the S.W. and the saponification
number; at the same time slight quantities of di- and tri-glycerides
are present
SUIMIMAPY.
1. The composition of the medium is of no consequence for the
secretion of lipas: by microbes; so that every source of carbon or
nitrogen, assimilated by a fat-splitting organism, will serve equally
well for the production of lipase by this organism.
2. The secretion of acids by microbes in a culture medium
diminishes the secretion of lipase.
3. Acids form compounds with lipase from which lipase is again
freed by bases. The acid-lipases diffuse like lipase through gelatin
and agar culture media; acid-lipases of higher fatty acids do not
diffuse ; acid-lipases do not decompose fat.
4. Hydrogenions retard, hydroxylions accelerate the action of
lipase. If the acid degree of a medium exceeds */,, N no more fat-
splitting by lipase takes place. Lipase behaves to acids as a feeble
basis. .
5. Calcium- and magnesium-ions favour the action of lipase;
likewise trimethylamine and natriumglycocholate; monovalent alcohols
counteract the process, sugars and glycerine exerting no influence.
6. Presence of oxygen and light favour the decomposition of fat
by the action of lipase.
By means of microbic lipase fat may be synthetically obtained.
From oleic acid and glycerine chiefly the monoglyceride results but
besides, probably a little di- and triglyceride.
eel
8. Microbie lipase shows great similarity to liver- and pancreat:e¢
lipase.
(1214) 5
Physics. — “On the value of the critical quantities’. By Prof. Dr.
J. D. van per WaAats.
(Communicated in the meeting of March 25, 1911).
Originally by the term critical quantities we understood the volume,
the pressure, and the temperature of the critical point. For the value
a as 5S a
57 be and i
been derived. But in the determination of these values it has been
supposed that the quantity 6, which had proved to be variable
with the volume, would have changed only so little in the
critical point that it might be put equal to the value which it
has in infinitely large volume, and which will be denoted by the
symbol 6,. But this equation 6,=%6, implied at the same time
db aig)
the neglect of @) and of ( a In course of time the value
k k
of these three quantities vo, = 36,, pz = - has
oO7 hk
ad by
dv dv
of other quantities, as they appeared to be in the eritieal point, have
come to the foreground.
In my communication on Quasi association (These Proc. XIII p. 107)
I | ti | PRY lle JR, ihe 1 Tdp f a f— l
lave mentione = ——— = 115 0, || —— | = .
De NE Rats Ph DA ii) ae enn
and ( jaz. which together with the above three quantities
k 8
v—
a 1 a a sr
ae and i —— ears
by® (f—1)r* by (fl)
of 8 quantities, which, however. are not independent of each other.
If the quantities @ and 6, are determined by the choice of the
substance, the knowledge of 8 quantities, viz. 7, s, and fis sufficient
to caleulate them all.
From the property of the critical point follows that it is that point
: ; ; : ' . a dp ip
of the tsothermic line for which the quantities {—] and {( —
dvu/T dv? }7
v,—rb, and pe= forms a number
are equal to 0. So two equations must suffice for the determination.
By means of these two equations the quantities v, and RT, are
determined, and further the value of p, by means of the equation
for p itself. Also the other critical quantities mentioned are then
derived by simple mathematical operations. If we put for p:
Fede a
the two equations for the determination of v, and RT, are;
(i995
= db
RT| 1—-
dp dv 2a
dv (v -- b)? vy?
and from the differentiation of 1 and after elimination of R77’:
v d*b
v 1 db» . 2 du? 33 7
a a) Dae ee
—
dv
If / was known as function of v, Il might serve for the determination
of v,, and by means of this I might yield the value of R7).. If
; : b > by 5
for all substances a same function ; = ij existed, the same value
i v
)
b, :
would always be found for —’ from II. In other words the quantity
Uk
r in verb, would have the same value for all substances. But
a
then 27; would be an equally great fraction of — for all substances,
"9
s aia v 1
and p, an equally great fraction of —,. In the same way {| |, | = —
7 dg RI s
would have the. same value for all substances — and particularly
ihe investigations of SypNeY Youne show us that great differences exist
in the value of s for the different substances. So we are compelled to
; fo b b
abandon the assumption that in —=/ =) the course of a would
9 C 9
be the same for all substances. It is clear that this brings the
question what may be the cause of the circumstance that 4 becomes
smaller with decreasing volume, to the front again, but for the
moment I shall pass over this question in silence. That the value of
Vk. . F :
7 =— is smaller than 38, and ean be different for the different
9
substances, I shall, however, assume as certain. And in the same
way that + descends the more below 3 as } descends more rapidly
with v. If we assume a real diminution of the molecule as cause of
this variability of 6 with v, we might put this as follows: the quantity
r is the smaller in the critical state as the molecule is the more
compressible.
But whatever may be the cause of the variability of 6, the law
k , so. Cle v ab :
of this change is unknown, and the quantities and SPs which
av a du
occur in the equations I and IJ, are unknown. This excludes the
C1180)
possibility to make these equations serve for a determination of
Uk 7 5
— and of RT). Reversely, however, they can serve to determine
by
db v d*b 3 a4 ai :
7 and Rae for the critical point, if 7» and R77 are known in
v Pe Oe
another way. In consequence of the disappearance of two equations
: : ‘ A ele Uke
which might serve for the determination of — and R7})., we must
)
9
seek two new quantities which might serve us for this purpose, to
which the circumstance is added, that now the equality of ber
also disappears. Hence the knowledge of the 3 quantities 7, 7, and s
is necessary for the determination of the critical data.
I shall assume the equation of p in the simplest form, viz.:
only with the addition that 4 depends on v. But I shall assume
dependence on 7’ neither of a nor of 6. In my investigation, entitled :
“Quasi association” it has been demonstrated that such a dependence
on 7’ cannot serve to account for the differences with the experiment,
but that only the hypothesis of association can effect this. This
removes the necessity of the assumption that a and 6 should be
temperature functions. But of course this does not refute the possi-
bility for such a dependence. Here | will investigate, however, in
how far the results, obtained on the most simple suppositions, accord
with the experiment, and not introduce again an unknown dependence,
e.g. of 6 with 7, which would, of course, render the derivation of
a definite numerical value, impossible. In my ‘Quasi association”
I have demonstrated that it is probably not of influence for the
critical quantities in the shape to which I then reduced them,
v /
except for the quantity fas in a slight degree. The influence
U—— 0: s J
of quasi association on the value of the critical quantities being so
slight, I shall neglect the quasi association for the sake of simplicity
in the derivation of the relations which exist between the critical
quantities, either accurate or by approximation. I shall only calculate
at the end the extent of the deviations which are the consequence
of this association.
Differentiating the equation for p with respect to 7’, keeping v
; dp R aif Gyo RT a
constant, we find {—])= or 7 | — ) =>—=p+ —; and as
v v
RD) oo
( 1214 )
; ' dp eee
In this last equation (5) represents the increase of tension of the
ler
Lf
saturate vapour, as it is at the critical temperature. We may also
wrile :
Dh: 22) 1 a
pal) x, a pvr
or
a
Le ie
Vie = —-— |).
P dp ye
And putting v7, = 7b,
a il
| te I
a he Peep he ee
p aT ss (Z)
For a number of substances the tension of the saturate vapour
has been experimentally determined up to 7, — and especially the
values of p for some thirty substances have been given by Sypney
Youne in “The Scientific Proceedings of the Royal Dublin Society”
(June 1910). These tensions have been determined for temperatures
between 7). and about 4 7).
By approximation they are indicated by the empirical formula:
5 a ee
— Nep log — = f ———
as eae)
or
l—mn
— Nep log x = f—— .
m
But the quantity 7 is somewhat variable with m; starting from
T;. or m=1 there seems to be at first some diminution of 7 with
descending value of m, which, however, has already been replaced
by a rise for m< 4, while for m= 4 the value of m has again
risen above /f;,. For still smaller value of m the observation is
prevented by the appearance of the solid state. From some pheno-
mena I have concluded as probable that e.g. at fj, = 7 the limiting
value of f would rise to about 9 at the absolute zero.
From this empirical formula we derive:
dx ip 1—m dfn
adm m* m dm
( 1215 )
or
mda The dfn
= SS nv
adm mm dm
m dx ;
— ——= 0 ie
aPOhD ihe 13
If we wish to determine the value of 7; perfectly accurately, we
are confronted, even with SypNny Youne@’s determinations, by diffieul-
ties. SypNEY YounG represents the form of p by the formula of Bior,
viz. Log p=a-+ ba? + cB; on the whole he succeeds in deter-
and so
mining the many constants occurring in the formula so that the
agreement with the experimental data is very satisfactory. But though
we confine ourselves to the socalled normal substances — so excluding
acetic acid and the aleohols — yet appreciable differences occur,
especially in the neighbourhood of 7’. Differences great enough to
‘mdx
be of importance for the value of le ) which is to be calculated.
kr
adm
A very elaborate investigation would be required to determine the most
probable value of /;. And perhaps the most reliable method for the
calculation of this quantity is the direct one; viz. by reading as
well dz as dm and a and m at temperatures near 7), from the
table of the observations. As an example | calculate for ethyl-acetate
from: ‘
p Ts
2OTLO™ 2 es eed
ZNOOO oe eee Oe
*cByA WU cana wee oo E'S)
28800)... 2 2 38250
DSSUN ss) eee eeAOO aL
Tdp mdse
From the two first observations follows for —— or the value
pal adm
M9ou>< ol'9 _ 430 522,5
ees TY 7,6. From the 3'@ and 4 observation ——-————_—7,86,
27137 <2 28585
while the difference of the temperatures is too slight for the caleu-
lation from the two last observations. The rise of p, which per
degree is equal to 595 at T=246, and to 430 at 7=249,5, would
namely suddenly be equal to 770 at 250,05. Thus much we shall
no doubt be able to conclude that /;, will not differ much from 7,6
or 7,8 for ethyl-acetate. I have thought I ought to call attention to
this uncertainty of the absolutely accurate value of /f:, as we shall
( 1216 )
presently subject a probable relation between the values of some
critical quantities to an investigation.
Let us now proceed to derive a value for R7;. We do this by
the aid of the value of what is often called “critical coefficient’,
which is also to be derived from the determinations of SypNry Youne
and given by himself; viz. the quantity s from the relation:
UT}.
PLL -
The uncertainty which exists in this quantity s is for the greater
part the consequence of the uncertainty in the value of v,. In most
cases vy. was not directly determined, but caleulated from the course
of the value of liquid- and vapour volume at temperatures near 7%.
This can be done with the aid of the law of the rectilinear diameter,
; : 5 dp ‘dp = = 4
or by applying the criterion | —. =(FF . For RT), we ‘ind now
; - aig AT ) hy
s.
the value:
RT, = ee ee
(RT;)? 3
=a. 2 het eee ey
Pk f-1
In my Quasi-association (These Proc. June 1910) I pronounced
the expectation that at least approximately tbe factor of a, viz.
2
s
= would always have the same value for all normal substances,
Ye
whatever might be the law of variability for the quantity 5. I have
since been strengthened in this opinion by the investigation of the
value of eT for all normal substances, for which the quantities s
and 7 have been determined experimentally.
s? : DJ
If 6 does not vary with v, the value of ae; is equal to = and
2
is always found equal to this value.
»
so we have to examine if
In order to investigate the correctness or incorrectness of this
relation as impartially as possible, I have taken the values for s
and / which are given by Kvrney (Die Zustandsgleichung ete.), and
then caleulated s from:
(4217 )
and compared this value with the given one. The values of / occur
on p. 142 and those for s on p. 60. KugnEN’s numerical values,
however, have been chosen so as to belong to the equation:
, l—m
—s log, , x=f'
m
st 64
and so to yield the values of / meant in the formula a = oe
KuENEN’s values must be divided by 0,4845.
FF f s calculated — s given
H, 2.10 4.835 3.01 2.94 (?))
Argon 2.18 5.02 3.08 2.67
O, 2.50 3.757 3.36 3:49 (?)
Ethylene 2.75 6.33 3.99 3.42
co, 2 86 6.58 3.636 3.59
Ethane 2.60 6 3.445 3.55
CCl, 2.81 6.47 3.606 3.67
Benzene 2.89 6.65 3.67 3.75
Fluor-benzene 2.99 6.885 3.739 3.78
Ether 3.01 6.93 3.75 3.81
Esters 2.97—3.25 6.84—7.48 3.715—3.92 3.86—3.94
First of all in this table the great difference in calculated and
given value of s for Argon is very striking — and this led me to
inquire into the cause for this great difference. Now before the
appearance of the Proceedings of the Royal Society of Febr. 1911
I happened to look through the proof, and in this way I got
acquainted with the observations of KAMpRLINGH ONNEs and CRoMMELIN,
who give values for /’ and s for Argon. There the value 3,283 is
given for s, so still greater than in Kurngn’s list. But on the other
hand /' is much greater than is given above. If we take the value
of f' at t= — 125,49, viz. 2.577, then f= 5.934, and we calculate
s=3.41; -- again appreciably greater than 3,283. This led me to
calculate the value of /; itself from the data occurring in the cited
communication. Specially because a sudden increase takes place in
the given value of /’ near the critical temperature, which is not the
case for other substances to the same extent. Between ¢ = — 140.80
and ¢= — 125.49 Kameriincn OnNes and CromMetin give four values
for f' for ascending temperatures, viz. 2.415, 2.421, 2.457, and
KOO
finally 2.577. The last value I have re-calculated and I come
1) The (?) mark is KUENEN’s.
80
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1218 )
to the conclusion that it is too large. In two ways I have tried to
determine 7’ and so also /. First of all by taking Ap, AT and p
and 7’ between the two highest temperatures, and substituting into
a al
TA ‘yy .
the formula /= P We find Ap=-6.611, A7=4.34, p=39,1515
pal
and 7’= 145.34 and from this = 5.66 — and in the second place
. pP . T,.—T ; ,
by calculating /' from — log,, —=/ 7 Then we find /'=2.425
S , Pk
and f/—=5.6. So the sudden inerease in the value of /' does not
exist. With f= 5.6 we calculate s = 3.29 —- which lies exceedingly
near the value 3.283 found.
1
So in this case we have an almost perfect harmony between the
s? 64
Fal Sis
stance with very low critical temperature. For one with a high
value of s, viz. ethyl-acetate, for which s = 3.949 is put by SypNey
Young, we get as good an agreement if we put f between 7.6 and
7.8, as was found above (p. 1215). With f= 7.7 we find s = 3.977,
while SypNrey YounG gives s = 3.949.
Only for helium a very great divergence would be found. In the
)
formula which supposes and the observation for a sub-
paper already mentioned in the discussion of Argon ay is put for
helium. To this corresponds f= 4 or f' = 1.7372 — while f/' = 1.2
is given as highest value. But then f= 4 is the lowest value for /,
which is possible according to the equation of state — unless we
should aecept the perfectly inconceivable supposition that } increases
with v.
Fa
the alcohols and acetic acid according to the observations of SYDNEY
YounG, we are in the first place struck with the difficulty to derive
the value of /; with any certainty from the observations. For
methyl-alcohol there is at the higher temperatures generally a great
difference between the observations and the formula of Brot used
by SypNey Younc -— differences which irregularly change their signs
at temperatures which differ only 1 or 7/, degree. As probable value
of 7, I have chosen 8.35. If the said relation between s and /
If we examine the validity of the relation
existed, s=4.17 would correspond to this, while SypNry YounG gives
s= 4.559. For methylaleohol the same difficulty in the determination
of f, holds, for this substance I think I have to assume the value 8.5.
According to the above relation s = 4.215 would correspond to this,
( 1219 )
while Sypxyny YounG gives the value 4.26 for s. For propylaleohol
I have chosen /;, equal to 7.78, which differs greatly from KUENEN’s
value 3.93. The value thought probable by me agrees almost entirely
with 3.39 instead with 3,98. According to the above relation s = 4
corresponds to it, while SypNey YounG gives s = 3,998. So tested by the
above relation propyl-aleohol would already be a normal substance.
But for acetic acid, for which at low temperatures the saturate
vapour already consists almost entirely of double molecules, the
relation does not hold at all.
If it is taken into consideration that the values of /, printed
unmodified in the above table are mean values, which may only
accidentally be the values of 7; —I feel justified in assuming that
Sa 64 : :
for normal substances — fay ey be considered as valid at least
| al
to a high degree of approximation. Accordingly I harbour the expec-
tation that further investigation will make the exception for helium
disappear. If, however, this small value of / is found confirmed on
further investigation, helium would have to be called a very abnor-
mal substance.
So the quantity @ is determined from 7), and p; by the relations
already given in my Thesis for the doctorate, at least to a high
degree of approximation.
In my Quasi-association I had arrived at this relation through the
assumption that in the critical point two quantities would have the
same values as follows from the assumption 6 = constant, viz.
sr = 8 and (f—1) 7? = 27. Then s’r? = 64 and after elimination of
3? 64 :
yr we get the equation 5 =e But the equation obtained after
o”7
7
elimination of 7 can be valid without sand ( /—-1) 7? being constant.
Thus eg. with sr=7,5 and (/-—1)r? = 23,34 the same relation
between s and / can be refound. So the question is now whether
both relations (se—=8 and (f—1)7r? = 27) may be considered as
valid to a high degree of approximation. As vy, could indeed be
determined experimentally, but not 7 =i I had arrived at the sup-
position sr=8 and (f—1)7r?=27, by assuming a value for r which
could not be far from the correct one.
| have tried to determine what would follow for different proper-
ties of the quantities in the critical point if the two relations men-
s0*
( 1220 )
; f ~ . by.
tioned should be perfectly accurate, viz. 1. For the quantity i’ 2
HH
: db : : v d’b
the quantity | —} , and 3 the quantity {| — — }.
~ \dvJz : 2 dv? J;
be . mas d
1. The quantity " is found by determining (peat : equal to
= lity i : aT );,
th deed! v r
= , or At ae ae —, from which follows:
p (v—b);, s (v-—)d)e i by
bg
b s
—~=r| |] — — ji.
bg ( =
With 7s 8, we should find:
b 8
yo SF
[ shall, however, not at once suppose rs = 8, nor (f—1) r? = 27,
but assume rs —=c,, and (f—1)r? =c,, and c, and c, to be variable
with 7. Differentiating the relation :
b rs Cy
— =f = Srp — =. 2. ss se & FV)
bg i Uj
with respect to 7 we get, because by does not depend on r:
db Se c, df de:
bgdr i (sf dr Sf or
or
dey pad 1 dey
du, fidr f @
From (jolts ete eee f
ay ( f—1) 7? =c. te 7S— + = 5 consi iG
rom ( f—1)r? =e, fo CLrey oh mae in consequence o
which we get:
dbp 1 2s(f—1) , ¢, (f—1) de, 1 de
1
du. fe ap if? c,dr if oh ;
one oF
And by means of the relation uae | = Constant, or
es Caer
4 de, _ de,
Cy 7 Cy
finally :
Ab 2s (f—1 de, f—2
Seg ot U yy cf J (Vv)
dv}. Nias Gp ips
The equation (IV) gives us the fraction which in the critical point
is the quantity 5 of bg. It appears, as was to be expected, to be
( 1221 )
dependent on the value of » for this point. If rs should always be
equal to 8, and (f—1)7? = 27, this fraction would be determined
by 7 and depend on it in the following way :
b 8
— = » — ——_
ba 27
pleas,
-
‘ s : b
For r= 3, the greatest value which 7 can assume, we find = 1,
Ta]
as was to be expected. But though this quantity decreases with the
decrease of 7, as was to be expected, this decrease is slight; thus
itl 2. tk Nt f pee
with 7 = he value of —=—.
bg 31
Equation (V), derived from (IV), reveals the direction of the
tangent to the locus (iV), and for the case that s7 would always be
b
d| —
: ; : bq
equal to 8, it yields for —~~* the value:
ar
2s (f—1)
ia
8 : : ae ss
which for s= e and f= 4 is equal to 0, for s= 3,77 and =‘
3.76 St, Bon
to ——, and for s=4 and f= — to —.
49 : 4 961
1
2. The quantity (G). This quantity is found from the condition
Gv / kr
dy
dp : ut
that {| — } must be equal to O in the critical point.
fi:
d
From (G)=° we find:
dv) T
or
Lae a f-1 u—b 8 ap MS
And substituting the value TG (| ete
ve RT). s 0 Jr f
which values already occur in my paper on quasi association, we find :
( 1222)
db 28 (f—1)
‘ (=) ie ( )
Comparing this value with (V7) we see that if ¢, should be inde-
pendent of 7, and so c, = sr always strictly equal to 8, the value of
db db. ., 4
would be perfectly the same as ——. But these two quantities
du) ky dv}.
do not mean the same thing. The meaning of what I have repre-
dv ] hey
The quantity 4, which is only equal to 6, for infinitely large volume,
decreases on decrease of the volume, whatever may be its cause
and the law according to which it decreases. Starting from very
large volume, the decrease is so small at first that it can practically
db : ; sake
sented by ( ) is clear. We have a substance with definite a and b,.
db
be neglected, and ,, may be put almost equal to 0. I have repre-
av
Sa ae : re : db
sented the value which has in the critical point, by {—]} .
dv dv) fy
The way in which, even for substances with the same value of
b,, the quantity 4 depends on v appears to be different, and this
circumstance calls up the question again, what is, after all, the
ae ae : db
cause of this variability of 6. At the eritical point a? ap and as we
9 av
db :
shall more fully discuss later on —, are very different. And the
av™
different way in which 4 depends on »v, is the cause, that the quan-
tities s, f and r differ in the eritical point.
b
d a
NG : :
But the significance of —~““, which quantity I have represented
b:
3 = yo s 5 5
in (V) by —, is another. The equation (1V), from which it has
dv}.
: ._ Ci 8
been derived, viz. — =r——=r{|1-—-—) enables us to calculate
; bg J ui
i)
A in the critical point, when 7, s and f should be known for a
Jy
substance, and may therefore be considered as a locus holding for
all substances, whatever may be the law of dependence of 6 with v.
So it does not belong to a single substance. If the dependence of
6 with v is given, only a single point of this locus refers to this
Hse We = Wel,
substance, viz. that point in which eS for that definite sub-
9
( 1223 )
stance intersects the locus. And if we knew this locus perfectly, and
b : :
also the value of — for that definite substance, we could determine
iy
bh. ;
the critical point by determining where — intersecis the given locus.
. Ig
b :
For greater values of 7 the eurve — for the definite substance lies
9
below the locus, and for smaller value of 7 above it. And it
db dbp,
follows already from this that {—]} must be smaller than — , or
kr
dv dv};
1 db Ss 1 dby.
Nav)» dey.
le
Then it follows by comparison of (V) with (VI) that = must
ai
be positive. This means that sv is equal to 8 only for += 3, or for
constant value of 6; but in all other cases, so if 6 decreases with
v, it is smaller than 8, and the more so as the variability of
is stronger.
a
Now the value of the factor of — for RZ; does not only depend
9g
° ° rs C, ‘ . 7 7
on sr. This factor is ~—-— or —. Representing this factor by F,
(f -1)7r° (Pe
dF de, de, (Be ‘ de, de,
ne Ce SSS —-——. And — being constant, 2 =—.,
Fdr — e,dr c,dr eG . cdr c,dr
dF de, : : ; :
Hence —_ = — —_.. To find this result, we might also have written
Fdr cdr
ie rc f a (rs)? 1 64 1
egactor of —: —— _— or ——.
a eG Iem © ok
which 6 is variable with v rs < 8, then RT, >
So if for all substances for
8 a
27 by
might also have been arrived at in a simpler way.
Let us imagine for this purpose two substances with given a and
and this result
6, — the former with constant 6, the latter with 4 decreasing with
diminishing v. If for given value of 7 we plot an isotherm fer both
substances — we see at once that the isotherm for the second
substance will always lie below that of the first substance. As for
every value of v the quantity v—d is greater for the second substance
than for the first, is smaller for the first substance than forthe
v— 0
a
second, and — being the same for the two substances, Pio py tor
v* :
( 1224 )
ereat volumes 4 for the second substance is only very slightly smailer
than ),, and for great volumes the two isotherms may almost be
considered as coinciding. But still, the fact remains that there is a
difference, and that this difference increases with decrease of volume,
and that this difference is the greater as the variability of 5 is more
pronounced.
; : ., ap : pi ee
At a value of v, for which =e —() in the isotherm which lies above
dp ea een
the other, : is positive in the lower isotherm. So the limits for the
av
unstable region are further apart in this case than for the upper
isotherm. But the displacement of these limits is more considerable
on the side of the small volumes. At the critical temperature of the
Ob aap
first substance, so at RZ, = — —, f will still be positive for » = 3hc
| J
27 bg’ dv
for the second substance, and so the temperatures will still have to
8 a : ad
rise, and become greater than —W—, before the critical temperature
a g
of the second substance is reached.
But though we know that sr is smaller than 8 in all cases in
which 6 becomes smaller at the same time with v, and the more
so as ) varies more rapidly with v, still we have no rule as yet to
determine the value of this quantity. Of course, this would be the
case, if the law of the variability of 6 was known.
bg ; ;
For instance, if a 1—a— could be put, which might be done
9 v
for not too small volumes, if the reason of the variability of 6 is
not a real diminution of the molecule, but must be ascribed to an
apparent diminution, as I already did in 1873. Then (IV) reduces to:
a TS
SSS 9 SS
a
and (VI) to:
a 2s(f—1)
ee rs
and with elimination of ¢, the approximate equations to:
1 2s(f—1
fe ey
u lf J
or
Bee ey 2 Z i i Leave
; ris
or
( 1225)
1 2 3f-—2
pees. ee ates Rom era ee ey CLAIR L))
sr 8 i
Horo = and f=4, we find of course again sr = 8, but to
© | 00
this a value of a=0O belongs. With s = 3,64 and f—6,6 we find
for CO, the value sr=7,1, which value is smaller than I had
expected. For ether, for which we may put s=3,77 and f= 7,
we find sr little different from 7,1. Small errors in v and f, however,
have a great influence on the value of this quantity. For 7 a value
is found little higher than 1,88. That in my “Quasi association” I
put sr little different from 8 also for substances like ether is, therefore
owing to a too high value for 7. If the value of @ is calculated from
i a —— = or from 1 = = os V—")
r ip r fe
little from */,. This result would be in perfect accordance with what
the theory had predicted concerning the value of @ in the approximate
formula used for spherical molecules. But we find another value of
@ for another value of s and /.
The relation between @ and / is given by the formula:
2s (f -1)
, a is found to differ
a—_=1— -
r 2
and by the aid of (VII)
This value of = is equal to 0 for f= 4 and s= = but for
greater value of f and corresponding value of s it is always positive,
as, indeed, might have been expected. It was, namely, to different
variability of 4 with v that we attributed the different value of /
and s. But the different value of @ is still inexplicable. Is the devia-
tion from the spherical shape the cause? And is, for the cases in
3 : .
which oP: another cause, a real diminution of the molecule added
to the cause assumed up to now for the decrease of 4? But the
assumption :
( 1226 )
bee by
—-=1l1—a-—
by v
. ; ; ‘ d*h
becomes altogether improbable by the consideration of the value of- i
av
2
v d*b ‘ nfl, eae :
3. The quantity € =) . This quantity is found from the con-
a av / kr
dv*
Equation (II):
d* ; :
dition that (52) is =O in the critical point.
r
v d’b
v db 2d 38
] -- - =
v—b =| db 2
| nes
dv
» a®b i db
yields for the value of ; =) if we put i =t and (: ~=)=
eae)
i i
» ab il —4
(ey I= aD Crab at hae UX)
2 dv? or
For #=4 we find this value again equal to 0. For f=7 and
18
s = 3.78 the value is equal to 0.54 x 76 or nearly 0,2.
The equation (IX) can be derived from (VI) without it being
necessary to have recourse to (II). Nor need (VI) be derived from (1).
b rs db
From the relation — =7—— we could have found {| — } from v by
bg J dv ier ;
keeping c, constant as should be done for a constant substance.
Then we get:
db 2s(f—1)
dom. tf?
and by differentiation of this equation, keeping c, constant:
ab —1 1 2
7 WS v= - 28 | — = — df
dv* ij 2 J 2 ij 3 Y
dvs att 4 4 i 2 ;
—(a)e al ee
dy d d
Writing for zs and df for 2 (f=, we find:
fs Vv &
or
( 1297 )
vd? rdf 4 rdf 8
be ak = = = 4
-(= My — | +5 = alata
df
v =) : s(f—1) (f—A4)
= ey dv? Pe ery ie ’
f- Ta r
vo db\ ent (: =)
ia Q dv? 2f dv ly
db
As { 1 — =) differs little from 1, we have in ——— an _ approxi-
Av) fey. 2f
v dy
mate value for — {~—-— ]}.
and
2 db? );,
v d*b\ . ; ! ;
The value of —|5—, } 1s exceedingly great, in comparison with
a WW / kr ig
db : é b
—], and this latter is again great in comparison with 1——. And
dv] iy bg
. 5 9 b by :
that this could not be accounted for, if we put b =1—a-—, is
9 v
: : a v db db ‘
particularly obvious if we compare — ate ——}. Putte
; 2 dv? dv kr
b bg - di bg?
— = 1—a-—, we find then |— ] = a@| —}, and in the same way
b, D dy, v
v ab ba\” : 5 .
(- =o )=e(2). The ratio of the two mentioned values would
2 v v
then be 1.
We might account for the high ratio between the two quantities
by an equation of the following form:
db bg \n+1 v d’b n(n-+-l)a (bq\"+1
Then —=nea| —~) and { — |= Gaia Z , so that the
dv v 2 dv? 2 v
. Then for the determination of n we have the
: n+1
ratio would be - 5
equation :
fil) (Fe=8)
nl if
2 a Ta (Gan)
2
cil
( 1228 )
8
For »=4 and s= 5 numerator and denominator are equal to 0,
but this case supposes b= 4,. For s = 3.78 and f=7 we should
find :
; 6 8
1.08 XS Xe
(ey
n + 1 = ——_—__—_—__ — 9,34
5
1— 1.08 x —
u
or
n= 4.34
For the determination of 7 we have the equations:
b 1 8
Spe
bar J
or
a
jee
ws s
ee
r J
or
db
i 1 s a = 8s dv
ro fo ormtl ih n
or
2s(f—1
. 120)
s
— !
r i n
For s= 3.78 and f=7 and n=4.34, we find:
1
— = 0,46 + 0,01713 = 0 47713
Ue
or
r= 2,0957,
And this value of 7 is, indeed, smaller than the estimation in my
“Quasi association”, but only very little.
On the supposition that sv should always be equal to 8, we should
find r= 2,116 — so that the difference would hardly amount to 1 °/,.
Hence we find s7< 8, as was demonstrated above, but only little
smaller, viz. 7,9217. And for (f—1)7r? we do not find exactly 27,
but a slightly smaller value, viz. 26,352. But the question what is,
after all, the cause of the variability of 6, is not answered yet, and
b b,\n
q . . . . .
== 1—a{—] is to be considered only as an empirical formula,
g @
holding by approximation in the neighbourhood of v,.
Now, nowever, it remains to investigate in how far the existence
of Quasi association has influence on the obtained results.
In general :
dp ie dp 4 =) da
Ci Na) de )ap\aT );
Perch (= \ebe: Wns irnoteritical’ domme al
ne eing equal to — in the critical point, also:
it), eq a cal point, also
n—1
ar |1—
, dp a in “| 4 dp r de
dT v- b dz) yp aly:
ZNG
i : ( ae ) | |
Ti ue =) = 1 we of wee i
dT v° ade) oT ars;
Now we have chosen the quantity n so, that:
or
or in such a way that:
zw
at i. ——
( | dp T dz (
ae eal 0 - Tih abs cp at)
aN : ;
Now the value of (=) is necessarily negative, and so the value
:
€
dp . F E ;
of {——]} will also be negative for the chosen value of n.
da ),-T
Though the y-surface has minimum value of 7% for a definite
value of wv, a section at given value of v will not begin with increase
of p, as is usually the case; but will always show decreasing value
da ° “Tt . . .
of p. The value of (z =) we must determine by differentiation of
v
dw
(a) = 0 and so from the equation:
oT
da
dw ay dw
+) dv + a! dx + be Ciie—0)
dazdv]T dx? ) 7 de dt) 5:
or
( 1230 )
1 “dw ly
= (ea oh ese) ipa et Veet
da) yT dz? J »?P da) 7
a: dp ab 4 dw Aes de dT
da)» da? Jur dz) 7 I
And (3se==—— ia ——
or
d* b)
The value of (=) I gave (These Proc. June 1910) in the form:
v]’
dy py eee a |
dx? ) oT nu (1—.) Lv RI
But there has an error slipped in there, which is indeed without
influence for small value of w, but which I must yet rectify. As this
would here divert us from the question we are dealing with, I shall
discuss the way in which the rectification is obtained, later on, and
now only give the corrected value. We should find:
d*w ae 1 a |
dz? Jp } » GN 2vRT |
nn (1—a){ 1 x
n
aie dx\ , : : :
Substituting the value of (7 =) in equation («) we find with a
v
high degree of approximation (for small value of 2):
eS
—— (7) N28 A en 0 ee
T
If we write the value of p in the following form:
( 1231 )
n—l
er(1— )
a n
ar v = v—b + v"
ee : a dp Baie :
Bearing in mind that p-- == Ms we find for small value of z:
v d
d Jed dp
(Pe Tee
dl v—b az )»T
according to (3)
pe _ RL ek 1
a a a e )
n — 1
a
or dividing by p:
: v x
= s —-§ =
J v—b (= )
n{| — —
a
v i
So the value of is found to be somewhat greater than = but
(Sh) s
so little that our foregoing calculations can remain unchanged.
Geophysics. — “On tidal forces as determined by means of
Wiecnert’s astatic seismograph’. By Dr. C. BraaK. (Com-
municated by Dr. VAN DER Stok.)
(Communicated in the meeting of March 25, 1911).
In a previous communication the E—W component of the semi-
diurnal lunar tidal motion of the ground at Batavia, as deduced
from registrations of Wincnert’s astatic seismograph during the
period of July to December 1909, was stated to be :
0” :0114 cos Qi—251~ 53%);
whereas the theoretical value is:
0’’.0155 cos (2t 270°)
The registrations obtained during the following half-year have
now been worked out upon the same plan and, in addition to this
tide, the other principal tides have been calculated for the whole
period of one year, except the semi-diurnal solar tide, which is
strongly disturbed by the diurnal heat wave.
These tides, enumerated according to their importance, are :
1) These Proceedings XII. 1910, p. 17—21.
( 1232 )
M,, semidiurnal lunar tide E—-W. component
K,, Sun’s-moon’s-declination tide N—Ss. _
O, Moon’s declination tide 3 a
P, Sun’s declination tide 55 s
K,, Sun’s-moon’s declination tide K—W. x
M,, semidiurnal lunar tide N—S: a
As before, the semidiurnal tides were determined by first measuring
off the distances between the registrations at 7" and 10", 8" and
12" ete., and taking the differences (18—10)-—-(10—7) ete.
For the diurnal tides the same method was applied to the
registrations at the hours 16" and 10%, 10> and 4" ete.
The sensitiveness was deduced by determining the period of
vibration and the indicator-magnification, as explained in the former
communication.
As the position of the instrument has not been altered, the former
values :
234.3 (E—W) and 185.7 (N—S)
have been assumed for the indicator-magnification.
In the different months the following values were found for the
mean times of vibration :
E—W N—S
1909 July 10.0° 10.4
Aug. 10.1 10.3
Sept. 10.0 10.1
Oct. 9.6 9.8
Nov. She 104
Dec. 9.65 10.0
1910 Jan. 9.8 9.8
Febr. L0.0° 10.0°
March 9.5 Ory
April Qs wed
May Sys) ws)
June Oa S03
The equivalent pendulum-length as deduced trom these data is:
E—W pendulum: 22.70 meters
N—S - S Ae) 54
The variation of inclination correspondiug with a deflection of
1 mm. in the diagram is accordingly :
for the E—W component: 0'.0388
» 5», N—S component: 0.0466
( 1233
As has been noticed in the previous communication the method
followed of measuring off the distances mentioned above gives twice
the amplitude multiplied by 1—cos 3a (@ = angular velocity per
hour) for the semi-diurnal tides as the argument varies in 3 hours
not 90°, but 3a.
For the diurnal tides twice the amplitude multiplied by 1 — cos 6a
is obtained.
The deflections have been measured off corresponding to the time
signal, given 5,5 minutes before Batavia time; the arguments have-
been corrected accordingly.
The values of the tides mentioned above as found by means of
the records, and also their theoretical values on the assumption of
an absolutely rigid earth, are :
July 1, 1909, noon.
M,, E—-W observed value 0".01120 cos (2t—58°.0) *)
theoretical —,, 0".01544 cos (2t—45°.5)
M,, N—S observed value 0.00848 cos (2t—356°.9)
theoretical — ,, O".00167 cos (2i—315°.5)
K,, E—W observed value 0".00277 cos (2t—245°.8)
theoretical — ,, 0".00229 cos (2t-—269°.8
O, N—S observed value 0". 00644 cos (t—88°.2)
theoretical — ,, 0".00700 cos (t—312°.8)
K,, N—S observed value 0.00449 cos (t—313°.6)
theoretical — ,, 0",00945 cos (t—359°.8)
P, N—S observed value 0.00645 cos (t— 84°.2)
theoretical — ,, 0".00291 cos (t—9°.2)
North and West are reckoned positive ; July 1, 1909, noon has
been taken as the beginning of time-reckoning.
Although the E—W components, but for a somewhat excessive
value of the K, amplitude, closely agree with the theoretical values,
the N—S components on the contrary show considerable deviations.
That this disagreement is not due to errors of the instrument is
proved by the following values for the N —S component of the M,
tide, ealeulated for each hour. :
1) Owing to an error in the calculation, the difference between the observed
and the theoretical values of the argument is not the same as that given in the
earlier Communication.
fol
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1234 )
10h 0.348 cos (2¢ 170°.4)
Ld OI834 cos (2i—li7oo
12 0.400 cos (2i—177°.3
41 0.3846 cos (2t—176°.5
2 0.414 cos (2t—178°.1
3 0.392 cos (2i—184°.2
4 0.420 cos (2t—188°.0)
5 0.367 cos (2t-—192°.4
For the N—S component of the O-tide, we found, taking together
two consecutive hours :
10 and 11 hour 0.123 cos (t—199°.2)
125, 2 5, OF199) cosn¢—229716)
2 , 3 ,, 0.899 cos ¢—235°.4)
4 ©» 4» Olste cos (t—20524)
The differences between these values are very small especially for
the M,-tide; for the O-tide the amplitudes show considerable flue-
tuations; but the agreement of the arguments clearly indicates that
the differences between the experimental and theoretical values are
due to an external periodical disturbance.
We shall presently see that they are caused by the watertides in
the Indian Ocean and in the Java sea.
If, namely, we assume the amplitude of the undisturbed gravita-
tion-tide M, to be equal to */, of its theoretical value — an assumption
which cannot lead to an appreciable error considering the small
value of this tide in proportion to the disturbing force — if, further,
its argument is assumed to be equal to the theoretical argument, we
find for the disturbing force :
O"-00772 cos (2t—2°.3)
If there were no retardation and, therefore, high water coincided
with the moment of culmination of the fictive star, the tides would
be represented for the longitude of Batavia by the expression :
RN COSa(2t—oillseo))
and the disturbance could be explained if the kappanumber of the
ocean-tide is assumed to be:
North of Batavia 2°.3—315°.5 = 46°.8
South ,, » 2°.8—815°.5 + 180° = 226°8.
Applying the same reasoning to the O-tide (where, of course, the
accuracy is less owing to the greater value of the amplitude if 7/,
of its theoretical value is assumed) we find for the disturbing force :
O:00765 cos (—T5.-7):
As, for kappa = 0, the watertide is :
( 1235 )
R cos (¢ — 312.°8)
the kappanumber ought to be:
North of Batavia 122.°9
South ,, 3 302-°9:
Now the tidal constants according to VAN DER STOK') are:
Kappanumber Amplitude
in em,
M,-tide S. of Batavia 225° 49.6 *)
ee) po NG oes 5 304° 3.6 °)
Om +5, See 3 268° dare)
aa ps mee ay te . 129° 97335)
If, as is reasonable, the principal disturbance of the M, tide is
ascribed to the Indian Ocean, where semidiurnal tides are paramount,
and, on the contrary, the disturbance of the O-tide is ascribed to
the Java sea, where diurnal tides are prevalent, the agreement
between the kappanumbers, as calulated from the disturbances and
as observed, is very satisfactory.
A closer inquiry into the influence of the K, and P tides would
be useless; the period of these tides being but slightly different from
that of mean solar time, meteorological influences probably cause
considerable disturbances; the results for different hours therefore
show large discrepancies :
K, tide for 10 and 11" 0.167 cos (315.6)
for 12 and 15 0.532 cos (¢—224.°8)
P tide for 10 and 11" 0.187 cos (t—349.°7)
for 12 and 15 0.538 cos (t—145.°3)
Probably annual variations in the diurnal heat wave, and the
intensity of land- and seawinds have an important disturbing influence °).
On the assumption that the disturbances acting upon the M, tide
are wholly due to the watertide, the disturbance of the #-W com-
ponent of this tide can be eliminated, as the disturbing force, acting
on the £-W pendulum, in this case, has a difference of phase of
about 90° and, consequently its influence on the amplitude is small.
If we look at Van prr Srok’s chart of homocumenes *), it appears
that, south of Sumatra from Padang to Vlakkehoek, the kappanumber
1) Kon. Nederl. Meteor. Instituut. Mededeelingen en Verhandelingen n°. 8.
Elementaire theorie der getijden. Getijconstanten in den Indischen Archipel, 1910.
2) Amplitude at Tjilatjap, kappanumber according to chart of homocumenes.
5) -r and kappanumber for Edam, Tandjong Priok and Duizendeilanden.
z) %9 33 53 for Tjilatjap.
Y) ” 3 for Edam, Tandjong Priok and Duizendeilanden.
6) With sudden increase of the wind and the beginning of rainshowers, the
direction of the wind can easily be traced on the seismograms; the deflections
caused by these agencies amount to 1 4 2 mm. in maximo.
7) loc. cit.
81*
( 1236 )
(relative to Batavia time) is about 200°, whilst its average value in
Sundastrait (Telok Betong, Java’s 4% Point, Labuan) is 210°.
It is therefore reasonable to assume that over the whole region,
where the disturbance exercised on the /+IV pendulum originates,
the kappanumber varies but slightly from 200°, say not more than 10°.
If we now calculate the disturbing foree and the undisturbed
earth-tide on the assumption that the kappanumber is 200° and that
the argument of the undisturbed tidal motion of the ground is
equal to its theoretical value, then we find *):
Amplitude disturbing force 0/’.0026
-- corrected earth-tide 0’".0118
For the proportion between observed and theoretical amplitudes
in the case of a-rigid earth this gives the value 0.76,
Hecker also found for the “-W component the factor 0.76, and
Ortorr*) at Jurjew gives 0.63 as deduced by means of a ZOLLNER
seismograph.
If we summarize the results given above, it is in the first place
evident that great care must be taken in the choice of stations to
be used for the determination of earth-tides, and that places situated
in the vieinity of a sea with considerable tides are unsuitable for
this purpose.
Further the unsatisfactory results obtained for the K, and P
iides justify the conclusion that, in order to determine the constants
of these tides, the instruments should be erected in a place sufficiently
deep to eliminate tidal motions of meteorological origin.
It appears, further, that Wriecaerr’s pendulum is a very reliable
and sensitive instrument, well suited for the determination of tidal
motions and that, by means of its records, the diurnal as well as
the semidiurnal tides may be determined without changing the
erection usual for seismographic purposes.
If only the constants of the apparatus have been determined with
sufficient care the material at present available from seismographs
placed in favourable situations might at once be used for tidal
researches without extra expense and the knowledge of the tidal problem
might in this way be considerably extended.
For Batavia it proves to be possible to deduce the semidiurnal
lunar tidal motion of the ground in the /- W direction notwithstanding
the disturbance due to watertides.
Weltevreden, February 12, 1911.
1) For kappa = 190° and 210° the amplitudes of the disturbing force are respect-
ively 0”.0025 and 0.0028, of the corrected tide O'.0114 and 0".0123.
2) Astronom. Nachr. No, 4446. Bd. 186.
( 1237 )
Microbiology. — “An experiment with Sarcina ventricul’’. By
Professor Dr. M. W. bBrtrrtncr.
Some years ago I presented a paper concerning a method to
obtain and cultivate an anaérobic fermentation Surcina from garden
soil.*) As the microscopic image and the dimensions of the thus
obtained organism corresponded in all respeets with the Sarcina of
the stomach,*) of which Surincar *) has given so exact a description,
I already then tried to prove their identity by experiments, similar
to those with garden soil, with material containing stomach sarcina,
which I owed to Professor van Leersum at Leiden. These experi-
ments, however, failed. A later one, made at Leiden after my
indications, proved likewise unsuccessful.
My supposition that the cause of the failure might have been a
too strong aération of the infection material by which the anaérobic
stomach sarcina had lost all its vegetative power, induced me to
pay special attention to this point at a renewed experiment for which
Professor vAN Lrxrsum again afforded me an opportunity in the
Academic Hospital at Leiden.
‘It was proved that my supposition had been right: when trans-
ferring the contents of the stomach with the sarcina to a fit culture
liquid, so quickly that contact with the air might be considered as
excluded, it was possible to make the growth and fermentation
proceed vigorously.
The experiment was managed as follows.
Some bottles of about 130¢.m.*° were filled with boiling malt
extract quite freed from air by previous boiling. The malt extract
was prepared by soaking about 20 g. of grist of kiln-dried malt in
80 g. of water, saccharifying one hour at 68° C., boiling and
filtering. Some bottles were acidified with phosphoric acid to 5 em*
N per 100 cm*, some others to 10cm’ N, and others were not acidi-
fied at all. The acidification was applied as the experience with the
sarcina of the soil had taught that this organism endures a high
1) Proceedings of the Meeting of 25 February 1905 p. 580. Archives Neér-
landaises Sér. 2, T. 9. page 199, 1905.
*) Discovered by Goopsir, History of a case in which a fluid, periodically ejected
from the stomach, contained vegetable organisms of an undescribed form. With
a chemical analysis of the fluid by Witson. Edinburgh Medical and Surgical Journal,
T, 57, p. 430, 1842. Witson asserts he has found acetic acid in the gastric
juice, but does not speak of lactid acid, which is in fact produced by Sarcina
ventriculi. :
5) De Sarcine (Sarcina ventriculi Goopsir), Leeuwarden 1865.
( 1238 )
degree of acidity much better than all other microbes occurring in
the soil, so that the same might be expected with regard to the
stomach sareina if this were indeed identical with it. The further
course of the experiment confirmed the correctness of this expecta-
tion too.
The bottles destined for the experiment were cooled after closing
to about 40°C. and only opened at the moment the infection material
was at hand, which consisted in the contents of the stomach of a
person suffering of stenosis oesophagi. About 5 em* of it was intro-
duced into each bottle and that so quickly after the pumping out of
the stomach, that the material had no time, neither to be saturated
with air nor to be cooled considerably below the temperature of the
body. Microscopically a great many sarcines were to be recognised,
other microbes being hardly to be found. It is true that many yeast-
cells occurred, but they proved dead and originated evidently from the
yeast used for the preparation of the bread-porridge which the patient
had eaten. Rests of potatoes and rice were also recognised in the
contents.
Before proceeding the following observation may be mentioned here.
Directly after the pumping out of the stomach a little bottle was
also quite filled with the thus obtained contents only, closed with
a cork and placed in a thermostat at 387°C. The result was that in
this bottle, already after a few minutes, so vigorous a fermentation
set in that the cork was thrown off. As microscopic examination
proved that in this way a very pure Sarcina fermentation was
obtained, this simple experiment had for the first time demonstrated
that the stomach Sarc7na can be nothing else but an anaérobic fer-
mentation sarcina.
The acid titer of the clear filtrate of the contents was, according
to Professor van Lxrersum, 3.8 em* N_ per 100 em’, with phenol-
phtalein as indicator, whilst free hydrochloric acid seemed quite
absent, so that the acid must chiefly have been the lactic acid
secreted by the sarcina itself, -which is in fact very well possible,
as at laboratory experiments the sarcina of the soil grows readily
in somewhat saccharified meal-mashes and can form therein about
4 em'® N latic acid per 100 cm’. The striking purity of the sarcina
fermentation in so heterogeneous a mass as the stomach contents,
in which neither lactic acid ferments nor alcohol yeasts were to be
found, might have been explained by the presence of free hydro-
chlorie acid, this acid being much better tolerated by the sarcina
than by the other microbes. But as this acid seemed to be quite
absent, the said pure development of the sarcina in the stomach,
( 1239: )
all other organisms being excluded, is not yet quite clear. But we
return to our chief experiment.
The bottles prepared as described, arrived at Delft at a tempera-
ture of about 25° C. and were directly placed in a thermostat at
35°C. The result was that in all without exception, so as well
in absence of acid as with 5 and 12 em* N phosphoric acid, already
after some hours a distinct fermentation was visible. By and by it
increased in vigour and after about 18 hours the sarcina had so
much multiplied, that at the bottom of the bottles a thick layer of
the so characteristic microbe had deposited, from which an abundant
current of fermentation gases, consisting of carbonic acid and hydro-
gen, mounted upwards. This state continued about 24 hours before
the fermentation fell considerably.
My supposition that the earlier experiments had only failed because
the stomach contents had been too strongly cooled and aérated
during the transit from Leiden to Delft was thus proved to be well
founded, and now all doubt is excluded about the identity of the
soilsarcina of the hydrogen fermentations and the sarcina of the
stomach.
It is of interest still to note here that in this experiment the
addition of acid to the nutrient liquid had proved superfluous, as the
fermentation had gone on also in the bottles without acid. In these
latter bottles, however, many lactic-acid streptococci and lacto-bacilli
were visible already after 18 hours’ cultivation, which was not at
all the case in the bottles with phosphoric acid. Only the latter
could thus be used for the continuation of the fermentation by
inoculation into a new quantity of culture liquid, without the chance
that the sarcina might be overgrown and expelled by the lactic-acid
ferments. Likewise as with the sarcina of the soil, by some repeated
transfers into the described medium, acidified with phosphoric acid
to 13cm’ N per 100 ¢m*, it was possible within the course of three
days to obtain so pure a culture of the sarcina, that inoculation into
the malt extract without acid was successful, not any other microbes
coming to development.
The thus obtained fermentations have become very vigorous and
are not to be distinguished from the best fermentations with the
soil sarcina.
Now that the identity of the latter and that of the stomach is
ascertained, still the question exists how it feeds and multiplies
at the low temperature and under the other conditions of life of
the relatively cold soil, which must evidently be quite different
as well from those of the stomach contents as from those of the
( 1240 )
deseribed nutrient liquids, so rich in carbohydrates and various
nitrogen compounds, and at temperatures between 35° and 40°C,
The answer to this question | hope to give later. That the sarcina
should) only aecidentally occur in the soil and the mud of ditehes
and not multiply there, cannot be admitted on account of the
very common occurrence of this organism; near the Laboratory at
Delft, for example, the sarcina could easily be found to a depth of
70 em in all earth-layers, even in so small quantities of soil as 0.4
to 0.5 g.
Why the sarcina develops so easily in the diseased stomach is in
my opinion connected with the readiness with which this organism
grows in meal-mashes, supported by the absence of hydrochloric acid
which under normal circumstances inhibits all microbie growth in
the stomach. The general occurrence of the sarcina is perhaps
best shown by the following experiment. If some coarsely ground
rye is mixed with water and placed in a thermostat at 30° to 35° C.
it will the next day be found in astrong coli-aérogenes fermentation.
If then this mass is carefully examined with the microscope many
packets will be found of the sarcina in a state of very active multi-
plication. They clearly originate from the dust deposited on the
surface of the corn at the reaping, the sarcina being quite well
adapted to endure severe drying.
Although the sareina of the stomach, in itself harmless, can at
most be troublesome by the evolution of hydrogen, *) it should. still
be observed that development of this microbe is impossible in
absence of carbohydrates, so that at a flesh diet, if there were no
reasons to avoid such a regimen, it would soon disappear. A milk
diet, too, would have such a result, as well if the milk were
acidified by lactic-acid ferments, as without previous acidification.
So it was not possible in laboratory experiments to cultivate the
sarcina in butter-milk, and even fresh milk, acidified with various
quantities of lactic or phosphoric acid, gave only in few instances a
feeble growth. In absence of acid the growth of the sarcina in crude
milk is quite impossible, this organism being overgrown by the
other microbes.
') The periodical vomitting observed in some cases of stomach sarcina may be
connected with the accumulation of hydrogen, formed in the stomach.
——E—= Pee EO
( 1241 )
Mathematics. — “On the centra of the intearal curves which salisf'y
differential equations of the first order and the first degree.”
By Prof. W. Kaprnyn.
1. Considering « and y as the coordinates of a point in the plane,
the real curves which satisfy a differential equation of the form
dy Q
dz P’
present different singularities. Between these we meet with points
Q and P being polynomia in & and ¥ with real coefficients,
(foci which are asymptotic points for the integral eneves which
present themselves as spirals in the neigbourhood of such points.
These spirals sometimes change in closed curves and then the corre-
sponding focus is called a centrum, and it is a question of great
interest to determine the conditions when this happens. This question
has been solved theoretically by Poincaré, but meets with great
difficulties in. practice.
The object of this paper now is to examine the differential equa-
lion, supposing P and ( to be polynomia of the second degree, and
to determine all cases when centra may be expected instead of foci.
2. When the origin of coordinates is the point which must be
examined, the differential equation may be written
dy —#+aau’ + 2ey 4+ cy?
da ss y + av? + 2bey + cy?
where a, b.c, a',b', c', are real constants.
By substituting
= he 4- ky y= — ke 4+: hy
Se
the form of this equation is not changed, for we get
dy Ls S + a@'S? + 28'Sy + y'y?
d& im + a&* + 2Rey + 2,7
where
(A? +k? a =ah*® + (a + 2b) A?k + (26' 4+ c) hk? + clk?
(2? + kK?) B = bh? — (a -— b' — c) hk — (a + 6 — Co) ih Bik?
(2 + ky? y = ch? — (2b—c) Ak + (a — 20) A + ah?
(1? + kh’) a! =awh*® — (a — 2b’) h?k — (26 —v') hk? — ck?
(7 + k?)? B= Bh? —(a' + b— ec) hk +a — b' — 0) hE — bk?
A? + WY? y! = ch? — (20' + 6) Atk + (a' + 2b) hk? — ak
Now / and & may be chosen so that the six coefficients «2 y,
a’ 3 y' satisfy two conditions. Adopting
aty=2 adty=0
we have
( 1242 )
(7 -+- P)A=(atvht(a+ejk
0=(a+e)h—(a+c)k
so
a+e a +e
fea hoe an)
2 2
4 being a real number whatever, except zero.
From this it is evident that we may write
dy —a-+a'a? + 2b'xy — ay? —a-|-Y
de —- y + aw? + 2bay + cy? vA y+ X
where still ¢ could be replaced by a— 4%. As we do not want this
condition we will retain this coefficient in the old form.
Now after Porncar’s') theory here the origin is a centrum when
it is possible to construct an infinity of homogeneous functions of
order 7, satisfying the following series of partial differential equations
OF, OF, ; s
2 — — y— = 2aX + 273
oy ; av *
OF, OF, x OF, y OF, :
a See SS eS 2
Oy y Ow Ou Oy (2)
i I OF OF
OF, : 0 Benge es
Oy Ow Ow Oy
This leads to an infinity of conditions for the five constants a, b,c,
a,b’ and if these are all fulfilled the origin is a centrum and the
general integral may be written
wtyt+Fr,+F,+ Ff, +...= Const.
where the series converges until the closed curves, represented by
this equation, pass through the nearest singular point.
3. The equations (2) may be transformed as follows. If we suppose
, : OF, OF,
I’, to be a homogeneous function of degree nr, and « ——
dy” Of
OF , .
+ Y— will also
oy
OF,
Oa:
be divisible by «X -+-’yX. For eliminating the differential quotients
between
io be divisible by «X + y7Y, the function Y
OF, US Se ,
ges — y— = (#X + yY) Pr—s
Oy “Ow
‘) Journ. de Math, (1885) p. 173.
( 1243 )
eee 5 eee,
Oy 0 Uv
OF, OF ,
ah ce
we obtain
(eX + yV)(eY — yX) Ph_s — U(a? + y’?) + n(a#X 4+ yY) F, = 0
which proves that Ul’ is divisible by «V+ 7V.
If therefore
(eX = iV) Pio
we have
(2¥ — 7X3) Pi—3 — (2? + y?) Prot nF,=0 . . . (8)
and the conditions for a centrum may be written
OF OF
aera Oe
OF, OF, OF, OF, : :
v tig i X eae } af = (#X + yV)P
OF, OF. OF , OF,
a an —y = = Xx an eral Fay == (eX yee:
where evidently P; represents a homogeneous function of order 7.
These conditions may be further reduced, for
OF , 9 OF, 2 r
aati yt — (ex gee
Or Oy :
OF, 9 OF, 2
a a5 ——y¥ cL = (2X) = yi) P49
Oy Ou
give
Gis 22 ep age
Ox
OF 49 .
a NE = Pee ey
Oy
hence
n) d |
— fe I re a XP, ni P,
a | v l = an 1 ste ¥y ’
or
&
Py Oe, OP Cy ee ox x
Le EPs qi apy ee ee Piece ts
Oy ” Ox Ou dy Ow
Remarking that P, = 2, the conditions (2) may ha be replaced
by these
( 19d4 9
oF (Rok a ee
i oy J Ow & 1 rt 5
a ee ee :
% Oy 4 On ob Of y oy on T Oy af ( )
OP, OP, Be OP, ae OP, ANC 1a)d4 Pp
‘ Oy —Y im ow Oy ; (35 ite Oy cay
etc.
4. Examining now the possibility of a series of homogeneous
functions P; satisfying the conditions (4), we introduce the values
X = aa’? + 2b ay + ey? Y= ax? + 206’ “ey — aly?
XO) ee At
+ —2(a+ b')e + 2(6—a)y.
Or dy :
Putting
1D a Nie) ON Day
the first condition gives immediately
p, =4(a —d) p, =4(e+4 0).
Thus the function P, divided by 4
P, = (ad —b) a+ (© 0) y =pye + py
always exists. Proceeding now to
PL = qe" + qey + Gy"
we find that this function exists when the coefficients satisfy the
following equations
q, = (8a + 26) p, + ap,
29, — 29, = (4b — 2a’) p, + 2 (a 4+ 2b') p,
—q, = cp, + (2b — 3a’) p,.
Therefore it is necessary that
(8a + 26'+ c)p, + 2(6—a@’)p, = 0
or that
(a — b)(a + ec) = 0.
By hypothesis a+ c¢='=0, thus the first condition is
a! 20 S10: ue es ee eo)
If this eondition is fulfilled gq, may be chosen arbitrarily, for
instance g, =, and we have
P, = (a + 6) [bay + (a + 26') y’].
From this form it is evident that this function and all the following
funetions P, P,... vanish when
EO SIP Ys. gees OD
( 1245 )
The origin is therefore a centrum if both the conditions (5) and ‘6)
are satisfied.
In this ease the integral of the differential equation
Qe wt ba® —2axy— by?*
de - yt. aa?+2bay+-cy"
takes the finite form
a +7? + F, = const.
where /’, may be determined from (8).
The integral curve
2 2
a? + y? — Bi bu*® + 2aa72y 4+ 2bay? + 3 cy* = const.
e
thus represents a series of closed curves round the origin of coordinates.
5. Assuming now
a’ =b and a+ b’==0
we may omit the factor a@-+ 6’ and write
P, = bey + (a+2b':) Y= q, ay + q, y’.
Now it is always possible to find a homogeneous function
Pi = 7,0? +r, aty for, ay? + ry?
satisfying the condition
oP, OP, OP, Pe a OXe On;
ot Uc Cl & at -) ze
and the coefficients are found to be
i g (a + 2c)
: 3
i SS Uk
r, = b (2a + 40' — c)
1
R= a (2a? + 10ad' + 36? + 1267).
Proceeding to
P.=s, 01+ 58, 0¢° y + 3,07 y? +s, zy? + 8, y*
we find that the following relations between the coefficients of P,
and P, must exist
Ge = (5a+2b')r, + br,
2s, — 4s, = 6br, + 4(a+0b') 7, + 2dr,
38s, — 3s, = d8er, + 3br, + (8a+6b') r, + 3dr,
S, 8, = 2er, + (2a4+86') 7,
= cr, — 3br,
4
Ww
v)
QW
i)
—
x
\
bo
%
I
( 1246 )
which are impossible unless
(5a+26'+-c) », + 267, + (a4 2b'+-c) 7, — 2br7, = 0
or
Dilute) (20. ——"Oa— (0c) 0s (ECA)
This condition breaks up into three conditions which will be considered
separately,
Supposing in the first place
a =) and 60
the differential equation may be solved. For putting
ro |
we obtain the linear differential equation
dt a 1 2b' +e — 2 (b' +c) z + ez?
—- i aus
dz b's 85" Z
.
A particular integral of this equation being
. t=a-+ Be ye’
where
20 +¢ 2 (b'-+-e) ¢
See o—
807 (a) *— 8b" (26'—a)
the general integral of the original differential equation takes the
form
a
fr? — 2 (a+B+y) + 40' (B+ 2y) y — Bb" yy} (1—2b'y) “ = const.
which for small values of w and y may be expanded in the form
ety + FB, -+ F,... = const.
In this case therefore the origin is a centrum.
7. If, in the second place
a= brand aco 0
the corresponding differential equation
dy — a+ ba? + 2b'ey — by?
da y + ax® + 2bay — ay?
has three particular integrals of the form
y =Ac + B
for substituting this value and equalling the coefticients of the different
ao ———
( 1247 )
powers of « in both members, we have
A (2bA — aA? -++ a) = 2b'A — bA? +
A(26B + A — 2aAB) = 20'B — 2bAB—1
AB (1 —aB) = — 6B?
which are satisfied by the roots of the cubic
aA® — 3bA® 4+ (26'—a)A+6=0,
and by
A
aA—b°
In this case, the general integral may be written
(y — nw) (y — y.)'2(y — ys)’2 = const.
where y, 7, y, Stand for the three particular integrals and 4, 4, 4,
are certain constants. To prove this we will show that the necessary
and sufficient condition '), that
my a a
(y ae 4) (y a Ys) (y aa Ys) i r
yy Y—Y YY
is divisible by y + aa? + 2bay — ay’, may be fulfilled by choosing
properly the constants 4, 4, 2,.
This condition may be written, t being a constant factor
Dede | Ae Se
A(Ys + Ys) + Aa (Ys + Ya) + Aa(¥r + Ys) = —(1 + 2ber)t
AY ss + As + AsYiYs = 9"T
or, replacing , 7, y, by their values
@) 4-+24,4+4,=— ar
O24, © 4) + 44, + A) + 24, $4) = — 2b
(¢) A(B, =F B,) = AB, =f B;) = A (B, +F B,) =—_t
Cie ALAM EASA 3 ALAS ar
Ca(A B.-A BY) 2(A.B, + A.B.) Ha(AlB, AB) —0
(ih) DS TERS Le IES Pay BSS
As
3b om
A, +4,+4,=—, 4,4, + 4,4, + 4,4, =—— 1 44,4, = —
the conditions (a) (6) and (d) may be written
1) Korkts, Math. Ann. 48, p. 350.
( 1248 )
4, +4, +4,=— ar
aA, + 4,4, + 4,4, = — br
4,4,4,.+ 4j4, A, -+ 454, 4, Sar
Hence
= —(A,—A,) (A,2—204
7 aS ;—A,) (aA,’—2bA,—a)
t 2
1 = ay (Aa — Aa) (A —2bA,—a)
T poke
i — ar (Ar As) (aA,°—2bA,—a)
where
N= A,(A,— A,) + 4,2(4, — A,) + 4,74, — A,)
and it is still to be proved that the three conditions (c) (¢) and (f/f,
are satisfied by these values of 2, 4,2,. Before proving this, we will
write 4, 4,2, in another form.
The values of B, B, B, expressed in the values A, A, A, are
found to be
B, = o(aA,? — 2bA, —a)
B, = o(aA,* — 2bA, — a)
B, = o(aA,? — 2bA, — a)
and it is not difficult to find the value of 6. For introducing
bB
A= —_——
aB—1
in the eubic, it is evident that the values of 6 are the roots of the
cubie
2a(ab' — b?) B® + (3b? — dab’ — a?) B* + 2(a + 6) B—1=0
Therefore
3b°—4ab'—a?
2Qalab' —b?)
B,+ B,+ B=
and
1
6 = ———_..
2(b?—ab')
Now
aA, — b)(a A, -— 6) (aA, — 6) = N,N,N, =
= @°A,A,A,—a7b(A,A, + A,A, + A,A,) + ab*(A, + A, + A,)—® =
b
= 20(b°?—ad') = —
aq
and finally
T 7
ho pn As 7:6) Uae
Tv 7 AT
Zh Ss DN A,(A,—A,)N,N,
T EAs
2, pn oats A,)N nN.
A;
With these values and B;= a the first member of (c) reduces to
=
ivi
py (4,—4,) [204,4, — 5 (4, +4,)] +
ab a An (Al Seiad At = pi(AeeAny
DL
+54, (A,—A,) [2a4,A, — 8 (A,+-4,)] =
T
= — SIA, (4,'=4,1) + 4, (44,7) + A, (424, =
Further, the first member of (e) takes the form
= (A,—A,) 4,4, [a (A,+4,) — 26] +
+ 5A, (4:—A,) 4,4, [2 (4,+4,) — 20] +
T
ae eA (A. — AL) AA’ a (As fh) = 28) = 0
bN
and the first member of (/)
T
py oa A 4) A,A,A, (,—4) 4. ae (A,—A,); = 0.
The general integral is therefore
Gy — A,& = By (y = An « — B. 2 (y — Aye — B 3)’3 — Const.
where
2,:4,:4, = (A,—A,) (@A,?—20A,—a):
(A,—A,) (@4,?—26A,—a) : (A, —4,) (@A,?— 2A, —a).
When the cubic in A has a pair of imaginary roots the corre-
sponding particular integrals are conjugate imaginary and _ therefore
the general integral is imaginary unless two of the quantities 2 are equal.
This is only possible if 6(a + 6’) =O and these cases have already
been considered in Art. 6 and Art. 4. We must thus suppose that
all the roots of the cubic in A are real.
82
Proceedings Royal Aeau. Amsterdam, Vol. XIIL
( 1250
For small values of @ and y the general integral may be expanded
in the form
wetyt f,+ F,+...= Const.
which proves that in this case the origin is a centrum.
5. If we assume in the third place
a’ =b and 26’ = 38a-+ 5¢
the corresponding differential equation takes the form
du —w + be? + (8a + 5c) vy — by? —w+YV
de y aft ax? + 2bay + cy? ees :
Here
Ope ai
and omitting constant factors we have, as before
i"
sy
P, = bay + (4a + 5c) y?
b
P= — = (a + 2e) a + b?a?y + b (8a + Ye) ay? +
1 2 Qh2 2 3
+ = (4a? + 115ae + 3b? +4 75c?) y? |
P, = s,v* + 8,0°y + 8,07y* + syay* + 8,y"
where
so ==0
> (8a? 10ae — 3b? + 10?
eeSiag (Se ac — 3b’? + 10c?]
S, = 126° (a + ¢)
s, — b (44a? + 107ac + 3b? + 66c7]
1
8, = | [B08a? + 1245a%e + BTab* + 1675act + 690%].
Proceeding to
P, = tu at tary ate tary? af t,a7y? = tey" = toy?
and
iP, == ue” ee ota = soe t= tha eg
we obtain
t, = (9a + 5e)s, + bs,
2t, -— 5t, = 8bs, + (lla + 10c)s, + 26s,
3t, — 4t, = 4es, + 5bs, + (13a + 15c) s, + 3ds,
4t, — 3t, = des, + 2bs, + (15a + 20c) s, + 4bs,
dt, — 2t, = 2cs, — bs,+ (17a 4- 25a) s,
—t, = cs, — 46s,
( 1251 )
from which always the coefficients ¢ may be determined, and
u, = (10a + 5c) ¢, + be,
2u, — 6u, = 10bt, + (12a + 10c)t, + 206,
3u, — Su, = det, + 7bt, + (14a + 15c) t, + 300,
4- 20c)t, + 4 dt,
du, — du, = dct, + Ot; it (18a + 25c)t, + 5b¢,
6u, — 2u, = ct, — 2bt, + (20a + 30c) t,
— u= c,— ae
From these th2 coefficients w may be found only when
(50a + 30cjt, + 12bt, + (14a + 18c)t, + 40¢, + (18a + 30c)e, — 2004, = 0
or when
20 4
=a bt, + (10a + 6e) (2t, — 5t,) + ai b (3t,—4t,) +
1 1
+ -z (B4a +300) (At, —34,) + 40 (5t, — 24) + | (1900 + 210c)(—t,) = 0.
Substituting now the values s, we have the condition
(a+c) [26s, + (lla + 9c) s, + 6bs, + (17a + 27) s,
]=9
or
b(a@ + c)(ac + 0? 4 2c?) =0. . «.. . 1. . (8)
If 50, the differential equation reduces to
dy —«#+(3a+ de)ay
dz y + ax? + cy? :
which has been considered in Art. 5
If a+c=O0 we have
dy —# + ba® — 2axy — by’
de y+ ax? ae Ybay — ay?
which has been treated in Art. 7.
When however ac = — 6? — 2c’ the differential equation takes a
new form
dy —cr + bea* mo (SOR c*) wy — a
dx ey — (8 + Qc?) «? + Qbe ay + o8
To solve this we will try to find particular See If the conic
wv? + 2Hey + By®? + 2Gy + 2Fy + C=0
satisfies the equation,
a+ Hy +G — oa + bow? == (6b + 6’) ey — bey?
Ae + By t+F cy — (b° + 2c? ) a + 2he ay + cy?
82*
( 1252 )
must be equivalent with
(a? + 2H wy + By? 4- 2G a 4- 2F y + C) (ae + By) = 0.
This may be done by chosing a= — (0?-+c*), #=0,
€ re iD 0
t= — i —, G=0. F= Or
b b b c? (b? + ce’)
Hence a first particular integral is the conie
ce
ba +c : 2e = (5
MOaTa CY): te oY Slats Te
In the same way we find that the differential equation is satisfied
by the curve of the third degree
2
(ba Ley)* +- 8ey (ba +cy) + dey + nae ==)
Combining these, the general integral is found to be
Pi rid
} bx bey)? + Bey e-tey) + Bey + ae
3
== Const.
fia 3
be-+-cy)? + 2¢ a
(be -+-ey)* Y+ Bre
which for small values of w and y may be expanded in the form
e+tytFr,+t+ F,+...= Const.
Therefore the origin is also a centrum in this case.
Resuming we may conclude that when the differential equation
is reduced to the form
dy —«+a'x?+2b'xy—a'y?
dz y+-ax?+ 2bay+cy?
the origin is a centrum only in the four following cases
x
ie a= 6, “and! a- 1b) =0
oe a 110
3 a =b, at+c=0 and the roots of
aA*—3bA* 4+. (2b'—a) A+6 =O all real.
4, a’ = b, 2b'= 3a+5¢ and ac+b?+2c? =
In all other eases the origin will be a focus for the real integral
curves.
ee ke
( 1253 )
Physics. — “Some remarks on the value of the volumes of the
coexisting phases of a simple substance.’ 1. By Prof. J. D.
VAN DER WAALS).
The main features of the curve which represents the volumes of
the coexisting phases as function of 7’, are known. It is a curve
which possesses a maximum in the eritical point for a volume which
is equal to 7b,. The value of 7 would be equal to 3 for substances
for which the quantity 4 is not variable. But for substances for
which 6 does vary with the volume, 7 is smaller than 3. As this
variability is greater, 7 will be smaller; it can be found by approxi-
mation from the relation s = 8; or more accurately somewhat less
than 8. In the critical point the liquid branch and the vapour branch
meet. At this meeting the curve has a continuous course. Though
this curve can only be experimentally determined at temperatures
above the freezing point, there is every reason to consider these
branches as also theoretically existing at lower temperatures. Even
at temperatures above the freezing-point the liquid volume falls
below the value of 4,. According to the determinations of SypNey
= oe ENE 1,3585
YounG the coexisting liquid volume at 0° is e.g. for ether the ica
hath}
part of the critical volume, whereas the value of 6, cannot differ
much from the = part of vy. And at lower temperatures this is
caf)
regularly the case. On the vapour side the volume continually
increases with decrease of the temperature on account of the great
decrease of the pressure, and the relation pv = RT’ is fulfilled more
and more accurately. This holds both for anormal and for normal
substances. Even for acetic acid, provided we bear in mind that the
value of A for bi-acetic acid is meant, and do not consider acetic
acid as an associating, but as a dissociating substance. But as long
as the volume still has a finite value, there is still deviation from
the law of the perfect gases, and SypNuy Youne’s observations (Proce.
Royal Dublin Society. June 1910) present a valuable contribution
to the discovery of the cause of this deviation.
That there will be a deviation, is of course to be expected according
to the equation of state, even though we should leave quasi association
entirely out of account. But the extent of the deviation could be
accurately calculated in this case. Now the question can be answered
if besides this cause of deviation there is another — and if we have
to assume quasi-association to occur in such great volumes as those
ily}: ))
of the saturate vapours, and if this is sufficient to account for the
differences found.
If we leave quasi-association out of account, the following equations
would hold :
1h an
a= p—b ae
or
up v a
RT v—b vwRT
or
vp a b
—————e («)
RY vk v—b
For the reduction to which I shall subject the second member of
the equation (@) I refer to my ‘Quasi association” and to my paper
in the Proceedings of the preceding month.
i , a no) Ole Bs Ah. Uke fx—l Tp
For the quantity —— I shall write -—-_—-—, or ———_—_; and
SRL vyevp- RT}, 1 ig al
though f, cannot be determined absolutely accurately, and this is
: Jk
also the case with s, we yet know ——— pretty accurately. If we
s
,
write — =m, we find:
Ty.
a ve tk—1 1
vRT vs m-
2 = ; = plac . pv
In many cases SypNey Youne himself gives the value of a In
the last column of his numerous tables he gives namely the ratio
of the real to the theoretical density of the saturate vapour. By
theoretical density he understands that which would correspond to
t
the formula “= 1. Thus he gives for ether of O° the value 1,028
for this ratio. So this means that for saturate vapour of ether at
pu 5 5 :
0° the value of = is equal to By substitution in equation
bo
[0 2)
)
(a) we have to investigate if:
1 ve fe—1 1 b
1028 v 5s m v—b-
Now it has appeared (see These Proceedings p. 1211) that even at
the critical volume the deviation of 6 from dy is only trifling. A
( 1255 )
fortiori this will be the case for great vapour volumes; and so we
can write:
or putting in the values v, and v determined by Sypnry Youna:
1 ees! 6 466,8 1 v
1,028 1209 nats 278 rp v—by
Now that we are dealing with such great volumes, there is no
objection to putting unity for -
ANG
, and for ether 7 will not differ
8 1
much from —, and so — may be put equal to 0,48. The value of
s Ts
the first member is equal to 0,0273, and that of the second member
to about 0,007. If such calcuiations are made at higher temperatures,
e.g. for ether at 100°, we find for the value of the first member a
greater number, viz. 0,172, and also for the second member a greater
number, viz. 0,107. The difference, however, has become greater.
Only at a much higher temperature this difference would again
become smaller — but the ratio would always approach unity. At
: 1
7). the value of the first member is equal to 1 — —, and after some
&
reduction the second member would also assume this value. And
What has been said here for ether, holds almost unmodified for all
substances examined by Sypnny YounG, though there is some difference
in the numerical values, which will be more fully discussed later on.
If we write the second member in the original form:
a b
URE pb.
the thoeght might oecur that by taking for a a function of the
temperature which increases with decreasing value of 7’, the indicated
difference might be removed. This, however, is only seeming, and
: 2 7 s UE tp—1 1
this is one of the reasons why I have chosen the form ——
v Ss WL
a . .
for saan That this only seems to be so, and that we run a risk to
a
make the difference still greater by putting such a function of 7’
for a, may be demonstrated in the following way.
’
" 4 k .
If we, namely, substitute ap TP for a, we have:
dp RT a Ten ie
—— YS) ——
ehh: v—b Zs vy" 3 (F Ts
, dp a ; Tye lr. Ohne
— — 9» = — }— + —
aT i al a a a
and
and
p aT pe v
So we have at 7;:
Tk —] a
—————— ~ — ¢ d
E TRS + © skr
F I VE (CIN rit a ie
Oo 2a Vice |= ara fe ll a Ries aie ee rence
Dy B
a| —
Do) Aiea female lel
vRT vm s l+ums
If we compare this value with that which we obtained on the
supposition of constant a, we see that it is
(1 +- a) m”
times smaller. This expression can be either greater than 1 or
smaller than 1. For #=1 it becomes 2m; and so for all values of
m above 4 the value which we had wished greater, becomes smaller
on the contrary.
Nor could the supposition that 6 is a function of the temperature
a
tend to make Saif larger. In this case we should find:
7
a % Te—1 Uke db 1
wRT v s (vp—br)? (dT ] ES m ;
The explanation of this apparently paradoxical result must be
found in this that if @ had been a temperature function, 7; —1
would also have been much greater, and we may accept this as an
indirect proof that the quantity a is no funetion of the temperature.
So we have to look elsewhere for the cause of the fact that
equation («) does not hold, and to put the question whether the
existence of quasi association can account for the found differences.
—
( 1257 )
From the form for p, in the case of quasi-association, viz. :
we derive:
pe a b v n—I a 7
i a —| 1 | INE
RT vRT v—b v—b n vRT 4
When applying this formula, when large vapour volumes are con-
cerned we shall no doubt be allowed to put 4 equal to 4,, and
aL
neglect ra the second member, and so we shall write this formula
in the form
aa pr ve (Tk -1 1 2 ) an » n—tl vn (fe—1)
RT: v ea
sm r v—b,
(3)
v—by n v sm
So long as v is large compared with vj we may, of course, put
if
= jl.
v—by
This equation (3) can serve to compute the value of « in the
saturate vapour.
The value of the first member of (3) for ether has been given
in the following table according to the mentioned observations.
0° 10° 20° 30° 40° 50° 60°
0,0203 0,0219 0,026 0,0335 0,037 0,0375 0,043
“0? 80° 90° 100° AMO? 120°
0,052 0,058 0,064 0,066 0,0675 0,07
d30° 140° 150° 460° 170° 180°
0,071 0,07 0,062 0,057 0,045 0,016.
At 7}, this difference, though it need not be equal to O, must yet
be a small fraction of 2;, as I have shown at the conclusion of my
paper of the preceding month '). These calculated values cannot be
considered as perfectly accurate; particularly on account of the un-
certainty in the value of 7 and of /f;. This latter quantity I have
put equal to 7. Probably the value 0,016 at 180° is too low.
The factor of w in equation (3) is the value of — at least
RT
with a high degree of approximation. At very low temperature the
1) Proceedings of this meeting p. 1211.
( 1258 )
. n—I sta tern ae .
limiting value is equal to . With rise of 7’ this quantity decreases.
7 nt
But we have coneluded to such a value of n, n > /, that the factor
of x is positive, even at 7%.
If we take n=9, then 20,023 at O° degrees, and « would
rise at ascending temperatures, and assume the following values:
100°. 110° 120° 1307 10S ee AKO}? alp0}”
z 0,088 0,095 0,103 0,118 0,12 0,122 0,13 0,136.
These values of # do not deviate too much from the formula:
Uy 1—m
log, wie
v m
and then point to a value of 2, = 0,16.
But this relation cannot hold in the immediate neighbourhood of
m1. Then the curve, which represents the course of v as function
of m, would intersect the line m= 1 at an acute angle, whereas it
must touch it. This follows also from the differential equation,
, T da
according to which — 7p depends on two terms, one of which is
av ¢
T dv T dv T dx
some times — —. As — — is infinitely great at T= 7, — — will
v dl v dl ys ’ 2 dT
es ane ae
also be infinitely great. The factor of ia is, however, small. So
:
the curvature of the z-line will be less broad at the vapour side of
the top — and v,—0,16 may be considered as an approximate
value.
I have subjected other substances investigated by Sypney Youne
to such an examination
and on the whole I have found a similar
series of values for « with small differences in the course, which
may later on yield material for investigation.
For normal pentane, which seems to have been investigated with
particular care, as determinations have been made up to the imme-
diate neighbourhood of 7;, I have represented the shape for « quite
accurately, and tested it by the experimental determinations. The
critical temperature is given equal to 197,2° and measurements have
been made at:
196°, 19655°° dob eee Odo andeelofedac.
The accurate form for wv is the following:
v TG eS vy (f—1) (1 =|
v—b v sm Rie n v—b v sm 4
The values of 7 I have taken equal to 7, that of s = 3,766, that
( 1259 )
of 4 = 2,05, and that of n= 9, and then we find for the value of
the first member:
0,019, 0,023, 0,019, 0,01, 0,023.
We find for the factor of x:
0,193, 0,176, 0,146, 0,12, 0,129
and for « 0,1 0,13, 0,13, 0.083, 0,18.
If we consider how many numerical values which are not absolutely
accurately known, have had to serve for the calculation, and how
greatly an error in the measurements affects the slight amount of the
expressions which determine , the agreement must be called satisfactory.
I have undertaken this investigation: 1 to see if in the observations
a support could be found for the existence of quasi-association, but
chiefly 2 to try and find out what is the cause of the anormal
behaviour of the alcohols. For this reason I have tried to determine
the value of « for ethyl-alcohol.
The same reasons which made me conclude to the existence of
quasi-association in general, apply also to alcohol. Very near 77,
op? : rz T dp
e.g. at Z only 0,6° different from 7; = 516,11, — a =} will) not
P a
?
differ appreciably from /,— 1, and B exceedingly little from 1 ;
Pk
. . . . vv ° 5
hence it may be asked by way of simplication whether ~~ is found
UK
equal to 1 + (L—m) or equal to 1-+-V 1—m. Now at
0,6 ;
1 — m = —— = 0,001164
516,
we find the value of 2 = 1.025 for alcohol. Now 0,025 is certainly
le
not equal to 0,001164, but of the order of } ‘1—m = 0,034. We
need only assume the value vy; = 3.63 given by Sypnny Youna, to
be equal to 3.61 to change the value 0,025 to 0.34. So we have
every reason to expect for alcohol just as for the so-called normal
substances, that a value for « will be found in the saturate vapour.
I may mention here that long ago | concluded to the existence of
molecule-complexes also for water vapour at 100°. Otherwise the
volume which would be theoretically equal to 1689, would not have
descended to 1649 a diminution too great to be aseribed to the
existence of a and & in the equation of state.
Proceeding in the above way, we find accordingly a value of x
in the saturate vapour of alcohol, and in the value of « a course
which does not deviate much from that which occurs for normal
( 1260 )
substances. Besides, also with regard to the relation I think I found
in my paper of the preceding month between the critical quantities,
oe 64
Fal see
Viz. alcohol behaves in a normal manner. With /;,= 7.9,
to which value I concluded from Sypnry Youne’s observations we
calculate s = 4,04, while Youne gives 4,026 for it as determined by
the observations.
If we apply the formula (y) for the calculation of aw, viz. ;
v ve f—1 pv nm—l v vy. f—1
— ———— — n{ — a
v—by voosm el bs n v—by v sm
we do indeed, meet with some irregularities for ethyl alcohol.
Thus for PY a same value equal to ——— is given as weli at 0°
RT 1.003
3 at 10°, 20°, 30°, and 40°. For 0° ee 0,00012, whiel
as a Ji, 4 > & > an J. - = S040 a 5 . “n
te j=l. zs :
multiplied by ——— is equal to 1,714 1,89 & 0,00012 = 0,00039,
sm
and which if we confine ourselves to thousandths, is too small to be
n
0,003. At
taken into account. At 0° we should then find «= j
n—
Vj: , 3.63 .
40°, when — has risen to 3170° we should find « smaller and scarcely
v 7
n
0,001. But even if we should disregard this irregularity, it
nea
strikes us that at 40° « is evidently so much smaller for alcohol
than it would be for ether in these circumstances and this suggests
the thought that 2 descends more rapidly with the temperature for
aleohol than it is the case for ether, or that perhaps it is smaller
at all temperatures.
The latter seems hardly to be the case at higher temperatures.
Thus we find the value of the first member for alcohol
at 130° equal to 0,044, whereas this value for ether for a volume
that amounts to as many times the critical volume, which is the
case between 60° and 70°, is equal to 0,05. At 190° the 1st member
assumes a maximum value, which is equal to 0,067, which maximum
value is only little greater for ether. And this maximum value occurs
for both substances at volumes which are about an equal number of
times the critical volume.
So our conelusion is that aleohol does not appreciably differ from
the so-called normal substances as far as its saturate vapour volumes
are concerned. But methyl-aleohol does behave in anormal way, both
( 1261 )
: rsa ; wore ‘
in the value of Fa’ and in the value of 2 near 7;. At a value
— Ul:
Uv,
of 1 —m=0,0029, and Vi—m = 0,054, is already equal to 1,14.
Vig
If also for methyl-aleohol for the saturate vapour we apply the
formula :
dp
. “| ee
v vy. f—1 pe dx) 7
v—by v sm Ree RL
and if we calculate the value of the first member from the data of
Sypney Youne, we find, indeed, the existence of a maximum value
just as for all the other substances, but it lies much nearer 7%, and
is much larger. Then we find for the value of the first member at
the following series of temperatures:
0° 40° 120° 200° 210° 220° 225° 230°
0009 0,028 0,072 0,094 0,24 0154 0,126 6,119
; ; 93 403
The maximum occurs for m— =, while this occurs at m = ——
513 466,8
for ether. Also in the volumes there is a great difference. For
ve 3,674 . JOSH ae we
methyl-aleohol —=-——_, and for ether ——.. If this irregularity in
v 11,58 27,49
the behaviour of methyl-alcohol is also to be ascribed to association,
either quasi or real association, this substance yet agrees in so far
, : dp aa:
with all the others that there is a value for ( ) , that it is even
aL) yT
negative up to 7Z;, and that the positive value of — RT
decreases with the rise of temperature, and has even become ex-
ceedingly small at 7%. But «, will be much greater than for the
other substances.
But even though we should confine ourselves to normal substances
the value of wz, appears to be much larger than I suspected when
I wrote my “Quasi-association”. It is true that I added there that I
did not venture to assert that the values mentioned there would be
correct. And immediately after the appearance of my paper I saw
that all the numerical values mentioned there for « would require
revision, which | have begun to do in this paper. Some of the values
mentioned then would even give unstable phases, which I hope to
prove later on. When judging about the value of 2 also in the
saturate vapour, it must not be overlooked that when a molecule
complex is considered as a compound molecule, the number of com-
pound molecules amounts to the #* part of this value of v. The
number of simple and the number of compound molecules is then
v
to each other as 1—-a is to —.
7
T dv
— for the saturate
v dT F
In conclusion a remark on the valne of —
rv
vaponr phases. Let us write aye which ¢ is the value obtained
1
when unity is divided by the values from Sypney Youne’s last table.
At very low temperatures this value is only very little smaller than
1, e.g. for ether of O° about 1 — 0,028. With rise of temperature ¢
me ~s 1 v
decreases, and for 7), it has descended to —. From —— =e we
8
derive:
T dp Tdv Tde
p dv gt 4. maew
from which follows:
Tdv T dp T dé
100 peat | ~ meses
£ T dé i z UT peak= . ' 3
Now _, Is negative, and — —— is exceedingly small for very
e dl : e dT s -
low temperatures. At the zero-point of the temperature the value
1 ;
would be equal to 0, and even for m= > it is still smaller than
T dw
e.g. —. But it rises continually, and for 7), for which — ——
4 : vw dl
is infinitely great, it will also have to be infinitely great. So there
is also a temperature for which it is equal to 1. We can calculate
from Sypney Youne’s table at what temperature this takes place,
T dv Tdp ;
and so at what temperature ———.—=-——_. This temperature cor-
v dl pd
responds to m—0,79. For the different substances m varies only
little. We shall discuss this temperature again, when we shall con-
sider it as the temperature at which the product pv has maximum
value.
. ; Ce
So below this temperature the quantity — — ap 8 smaller than
Vv
1 dp ele ;
5 dT” but it is greater in the interval m= 0,78 to m =—1, rapidly
P ¢
increasing as it approaches to 7%.
( 1263 )
Physics. — “The lines H and K in the spectrum of the various
parts of the solar disk”. By Prof. W. H. Junius.
§ 1. Causes of line-shifts.
There are at present four causes known, by which bright or dark
lines of the solar spectrum may be displaced with respect to the
position of the corresponding emission lines, as observed in labora-
tory experiments: radial motion, pressure, magnetic fields, anomalous
dispersion. Which of these causes is likely to be the effective one,
in each special case, can only be decided by comparing from a
physical point of view the possibility of the conclusions to which
the different suppositions lead us. If, e.g. we try to explain, by each
of the four principles, the strong line-displacements often observed
in the spectrum of prominences, it soon appears that both the second
and the third principle are unable to give satisfactory solutions of
the problem, so that, on further research, we shall only have to
choose between the first and the fourth. On the other hand, the
general displacement of the Fraunhofer lines toward the red,
increasing from the centre to the limb of the solar disk, can be
accounted for neither by Doppuier’s principle, nor by the ZkemMan
effect; so the interpretation of the phenomenon as a pressure effect
has to be compared, in its consequences, with the interpretation on
the basis of anomalous dispersion.
In a few cases there is scarcely any reason for doubt about the
origin of certain line-displacements. Nobody will hesitate to ascribe
the systematic differences between the spectra of the east and west
limb of the sun to motion in the line of sight; nor question the
magnetic origin of doublets and triplets in the spot-spectrum, which
show the polarisation phenomena characteristic of the ZEEMAN effect.
But such cases, where even at first sight only one explanation
seems possible, are rare. It would be rash, e.g. to make magnetic
forces at once responsible for the total widening of spot-lines, while
other causes, that also produce widening, are known. As a rule,
various influences co-operate; then the probably effectual cause of a
solar phenomenon will only be brought out as such indirectly, by
exclusion, that is, after other explanations have entangled one in
ideas, clashing with general physical laws. And the remaining
explanation will of course be the more probable, the better it joins
some theory, already giving a coherent view of many other solar
phenomena.
§ 2. Phenomena exhibited by the calcium lines H and K.
A remarkable case of systematic displacements, occurring with
( 1264 )
the calcium lines // and XK, was first described by Dasnanprus in
1894, then by Juwentt in 1896, and has recently been investigated
very carefully on Mount Wilson by Cuartes E. St. Joun *), and at
Meudon by Dersianprus*). The main character of these phenomena
is, that in the spectrum ef the central parts of the solar disk the
narrow dark lines //, and , are displaced toward the red, the
wider, bright lines /7, and A, toward the violet; that these displace-
ments decrease as we approach the limb, and that, on the other
hand, the width of those lines increases from the centre to the limb.
For further particulars we refer to the paper by Sr. Jonn.
The peculiarities of the phenomenon cannot possibly be explained
when pressure or magnetic forces are supposed to be the effective
cause. Sr. Joux, who takes no notice of anomalous dispersion as a
possible cause, is therefore so absolutely convinced of the radial-
motion nature of the phenomenon (and so are DusLANDREs and JEWELL),
that he deseribes the results of his excellent observations under the
title: “The general circulation of the mean- and high-level calcium
vapor in the solar atmosphere”.
We are going to show in the following pages, however, that all
of the properties of the lines /7 and 4, described by DssLanpREs
and Sr. Jonux, can be interpreted as consequences of anomalous
dispersion. Thus, fortunately, one is released from the necessity of
assuming, that in the solar atmosphere two opposite vertical currents
of calcium vapour are continually kept up, meeting or perhaps
passing or penetrating each other with velocities 30 or 60 times
greater than the velocity of the most violent terrestrial blasts —
and, marvellously, leaving the hydrogen and the other gases of the
chromosphere unaffected! The explanation on the basis of anomalous
dispersion does not involve such difficult physical notions, and offers
the advantage, that it easily fits a theory, already connecting a great
many Other phenomena.
§ 3. The injluence of anomalous scattering on the distribution of light.
The light coming from the lower strata of the sun, and having
to traverse an extensive absorbing atmosphere, loses intensity not
only by absorption, but also by scattering. It is true that radiant
energy, when scattered, only alters its direction of propagation, not
its nature (whereas, when absorbed, it suffers a change); so the
scattered energy must finally quit the celestial body in the original
form. But because part of it always returns to the source, we may
1) Guartes KE. Sr. Joun, Astrophysical Journal, 82, 36—82, (1910).
2) H. Destanpres, C. R. 152, 233—239,,. (1911).
( 1265 )
imagine that scattering retards radiation, and thus diminishes the
output per umit time.
For kinds of light differing little in wave-length from the absorbed
light, the coefficient of scattering is considerably greater than for
light of the remaining parts of the spectrum, its value being
proportional to the square of the refraction constant (according to
Rayiricgn), and the latter having great absolute values in the vicinity
of absorption lines. Consequently the neighbourhood of the absorption
lines must be more weakened by scattering, than the rest of the
spectrum; which means, that the darkness of the Fraunhofer lines
is partly due to anomalous dispersion.
How this conception of the solar spectrum follows from the theory
of electrons, has been shown elsewhere’). We must now recall to
mind some of the results there obtained.
The curve representing the refraction-
n—l :
constant A =—— as a function of 4,
A
has in the region of an absorption line
the shape, drawn in the upper part
of fig. 1. On both sides of the line
5
OP it approaches the almost horizon-
tal line P,P,, by which the course
of the refraction constant of the
medium would be represented if there
were no absorption line at O(A4=4,).
If we compare with each other the
absolute values of the ordinates of the
curve / in points, situated at equal
distances left and right of O, we find
them always greater on the right side
than on the left side. All effects, there-
fore, that increase with the absolute
value of n—1, will manifest themselves
more strongly on the red than on the
violet side of the line. This applies 1s' to the loss of light by
scattering; 2"¢ to the intensity of the scattered light; 3" to the rate
of variety of brightness that may result from ray-curving, when
there are density gradients in the medium. It follows, that on the
average (i.e. apart from local irregularities) both the Fraunhofer
W. H. Junius Selective absorption and anomalous scattering of light in extensive
masses of gas. Proc. Roy. Acad. Amst. XIII, 881, (1911).
85
Proceedings Royal Acad. Amsterdam. Vol. XIII.
( 1266 )
lines and the chromospheric lines are asymmetrical with regard
to the exact positions of the emission lines, so as to have their
“centres of gravity’? somewhat displaced toward the red. One can
easily show that this effect must increase from the centre toward
the limb of the solar disk. Its character corresponds exactly to that
of the systematic line-displacements, described in recent years by
Hare and Apams, Fapry and Buisson, and others, and considered
by those investigators as consequences of pressure in the veversing
layer. Objections to their interpretation, and arguments in favour of
our explanation which is based on the shape of the dispersion curve,
are to be found in former communications’). The part of the
dispersion curve, lying between the minimum and the maximum,
had not yet been taken into consideration then, that region being too
narrow, with most Fraunhofer lines, to be observable by means of
the spectral apparatus at present in use. But we are now extending
our discussion to that middle part of the curve, which may perhaps
reveal itself within a few very wide lines.
The lower part of fig. 1 (derived from the dispersion theory) shows,
for the environment of a single absorption line, the intensity Rh, of
the light transmitted by the solar atmosphere, if, for all waves con-
sidered, the intensity of the incident light is supposed to be S. The
influence of scattering appears from the course of the (partly dotted)
curve d,d,d.d,d,; that of absorption from the shape of the additional
part lying between d, and d,, and showing a steep drop at O’.
Only a few gases, strongly represented in the solar atmosphere, seem
to exhibit so strong an absorbing power, that the minimum and the
maximum of the dispersion curve are sufficiently distant from each
ether to make the phenomena, characteristic of the interval, perceptible.
Where this happens to be the case, we may expect to find,
according to the dispersion theory *), that the “centre of gravity”
of the central dark line is displaced toward the red, and that the
apparent emission line, which is due to the scattering effect passing
through a minimum at d,, shows a displacement toward the violet.
This simple deduction is in perfect agreement with the general
phenomenon, observed by Dersianpres, JeweLi, and St. Jonn with
the lines H, and K,, H, and 4,, in the spectrum of the central
parts of the solar disk.
§ 4. The influence of anomalous refraction on the distribution of light.
In order to find out how the effect will change as we approach
1) Proc. Roy. Acad. Amst. XIII, p. 2, (1910); “Le Radium”, VII, Oct. 1910.
*) Proc. Roy. Acad. Amst. XII, p. 895, (1911).
( 1267 )
the limb of the sun, we must fix our attention on another peculi-
arity of the propagation of light through matter. Indeed, anomalous
dispersion implies not only anomalous scattering, but also, wherever
the density of the medium is unequal, anomalous refraction.
Let us, for the present, leave out of consideration those “large-scale
irregularities’, Characterized by more or less ‘‘systematically arranged”
density gradients (such as probably exist in sun-spots) '), and imagine
the average condition of the solar atmosphere to be like that of hot
gases above a fire, i. e. a complex of irregular density gradients
strongly varying from point to point in direction, magnitude, and
sign. A very extensive layer of gas, thus constituted, must in some
way act as a turbid or seattering medium. The optical effect pro-
duced by such an atmosphere will be comparable to what we observe
when viewing a luminous surface through a plane-parallel glass tank
in which, for instance, water and glycerine have just been stirred,
bat are not perfectly mixed yet. This ‘‘scattering by refraction’ is,
like molecular scattering, specially strong for kinds of light from the
vicinity of absorption lines. So the effect of anomalous refraction is
in many respects very similar to that of anomalous scattering, and
will in so far only strengthen the latter.
jut we should not overlook the difference between the two
processes. The intensity of the effects of anomalous refraction depends
on the degree in which there happens to exist variety of density in
the medium. So it may be quite different at different places on the
solar disk *), whereas the intensity of the effect of molecular scattering
is more equally distributed, only increasing gradually from the
centre to the limb. And, secondly, we must notice that the direction
of the density gradients may strongly influence the intensity of the
light emerging from the solar atmosphere along a given line. This
cirenmstance too causes a kind of inequality in the distribution of
the light, such as molecular scattering could not produce.
We ate now prepared to inqtire into the changes, which the
distribution of the light in general, and the aspect of the caleitim
lines in particular, must show when we pass from the centre to the
limb of the solar disk.
Those changes are of course closely connected with the fact, that
in the central parts of the disk the main source of light has an
almost symmetrical position behind the atmosphere, but not in the
non-central parts.
1) Proc. Roy. Acad. Amst. XII, p. 273, (1909).
2) The irregular distribution of the light in spectro-heliograms can be explained
n this basis.
( 1268 )
A point Af somewhere in the
atmosphere of the sun will be seen
centre of the disk
on the by an
observer stationed on the line J/A ; ‘
but an observer on W746 will see it
not far from the limb. To the second Oy ess
observer the region round J/ appears =a) \
than it does to A :
much less bright
the first one. This proves, that J/
2 ; B
receives less light (perhaps only halt
direction O4)/ Fig. 2.
than along a. How, in a point J/, the intensity of the irradiation
by a definite kind of light depends on the direction of incidence,
can easily be found, provided that we know the average distribution
of the brightness on the solar disk, for the light in question.
as much) along the
In fig. 8 PQ shows the gradual
SS mal decrease of the brightness from
Be | the centre C toward the limb PR
of the disk for waves be-
tween 405 and 412 wy, accord-
4 | ing to
solar
spectro-photometric —mea-
surements by H. C. Vogrn'). Let
“lg RNC’ represent a section of the
photospheric surface, and suppose
eid 1/7) an observer to be placed at a
} | | | great distance in the direction
CC’; then it is clear that e.g.
from .V — that is, in a direction
making an angle ANB (= NCC’
= q) with the normal to the
photosphere, — an average quantity
of light proportional to the ordi-
nate mn of the P’ Q’-curve, emer-
ges from the solar atmosphere.
Fig. 3. We now define a point m’ on
the radius veetor CN by making Cm' = mn, and do the same on
the other radii of the section RNC’. Thus acurve 2” Q’ is obtained,
representing the transmissive power of the solar atmosphere for the
selected kind of light, as a function of the angle of emergence g.
With the aid of this figure we may now proceed to the construction
1) H. C. Voaen, Ber. der Berl. Akad., 1877, 5S. 104.
( 1269 )
of the “irradiation-curve’” for a point MV (fig. 4) situated in
the outer layer of the solar
atmosphere. For that purpose
we only have to take on each
line MV, lying within the
angle HA’ MH and cutting the
photosphere at an angle » with
the normal, a distance equal to
that polar co-ordinate of the
curve P’Q’ (fig. 8), which cor- Fig. 4.
responds to the same value of . Joining the end-points of the
vectors thus defined, we obtain the required irradiation curve qpq’.
It differs only slightly in shape from ?’Q’, and, as is easily seen,
would preserve very nearly the same character if J/ were chosen
in a lower level *).
Now looking for an explanation of the general decrease of bright-
ness toward the limb, it 1s only natural to make scattering respon-
sible for the phenomenon (both molecular and refractional scattering).
In fact, a// kinds of light are more or less liable to scattering, whereas,
very probably, absorption only extends to waves having the same,
or almost the same frequency as the free vibrations of the electrons
in the solar gases *).
The widening of the Fraunhofer lines toward the limb proves
that the gradual decrease of intensity from centre to limb is greater
for kinds of light suffering anomalous dispersion, than for the less
refrangible light from blank spaces of the spectrum. Accordingly, if
we construct the irradiation curve of a point J of the solar
atmosphere for one of the strongly refrangible kinds of light from
the vicinity of an absorption line, it will show a more oblong, oval
shape than the curve that has been deduced, in fig. 4, from
1) In this reasoning only the observed fact of the decrease of brightness
toward the limb was taken for granted, no hypothesis regarding the cause of
that phenomenon being required so far. ‘The result, therefore, includes the full
justification of the assumption on which our earlier considerations about the
propagation of light through the solar atmosphere were based, viz. that the
intensity of the light, incident on a small region M of that atmosphere, varies
rather strongly with the direction (Proc. Roy. Acad. Amst. XII, 268, (1909)). Some
astrophysicists objected to that view. Founding their refutation on the opinion, that
a point of the solar atmosphere receives equal amounts of light (per unit of space-
angle) from all directions meeting the photosphere, so that a circle s‘ps would
represent the irradiation curve, they evidently left the above-mentioned elementary
result of the observation of the sun entirely out of consideration.
2) Proc. Roy. Acad. Amst. XIII, 888, (1911).
(1270 )
VocEt’s observations on average violet light. This means, that for
instance such waves as correspond to the places d, or d, of fig. 1,
will reach a point J/ with an intensity that varies in a stronger
measure with the direction in which they left the photosphere, than
does the intensity of the average light.
Those very waves (near d, or d,) are at the same time especially
liable to changing their direction of propagation when there is a
density gradient at Jf. If we were not concerned with anomalous
refraction, but only with anomalous scattering, we should find
that a definite kind of light would have a constant intensity, at any
definite distance from the limb. But the refraction causes inequality.
And the chance of observing a conspicuous variety of brightness,
when Jooking at a region J/ of the solar atmosphere, which projects
on the disk at a given distance from the limb, increases with the abso-
lute value of n—1. By this circumstance we can e.g. explain a
prominent feature of the spectroheliograms obtained by Han and
ELLERMAN '), viz. the gradual increase of the contrasts in a series of
photographs of the same region, taken with waves, selected within
Kk, at decreasing distances from K,.
§ 5. The co-operation of the two before-mentioned influences.
The above discussion of the consequences of anomalous dispersion
suggests the following interpretation of the variable, bright ,-line,
generally supposed to be an emission line.
There are two causes by which the brightness may increase on
approaching Ky, .
One of them depends on the presence of the two small (unequal)
maxima of the R,-curve in fig. 1, indicating a diminution of the
loss of light by scattering. This influence acts almost equally in all
points situated at equal distances from the centre; it is strongest on
the middle parts of the disk; for in proportion as we approach the
limb, the scattered light itself will contribute a greater share in the
total emergent beam, thus levelling the curve and reducing the
importance of the two small tops. The part of the effect, due to this
first cause, is weak any how, even on the central parts of the disk,
but of a constant nature: it always yields a narrow, double A,-line,
displaced toward the violet, and produces a displacement of KA,
toward the red.
The other cause depends on refraction in irregular density gradients.
On the middle of the disk, refraction can only result in dininution
1) Hale and Everman. The Rumford Spectroheliograph of the Yerkes Observatory.
Publications of the Yerkes Observatory, Vol. Ill, Part I, 1903.
(eb)
of the original brightness, and this effect must be strongest for the
most refrangible waves corresponding to d, and d,; A,, which is
situated there between those wave-lengths, is relatively narrow. But
at some distance from the centre, where for every wave-length the
average brightness is less than at the centre, density gradients may
bring about, that light, emitted normally by the photosphere, curves
toward the observer, thus producing a local increase of brightness.
Now again we fall back upon the most refrangible kinds of light,
those at d, and d,, as the ones that will be able to produce the
latter effect in the strongest degree. Putting it otherwise: on the
non-central places of the disk refraction will here and there contribute
bright patches to the formation of the A-line, whose maxima of
intensity have the greatest chance to correspond to the wave-lengths
at d, andd,. This effect combines with the before-mentioned scattering-
effect. The components of A, must therefore, on an average, be
farther apart than on the middle of the disk.
Proceeding toward the limb, the first part of the effect, that which
is due to the dotted part of the scattering curve, diminishes, as already
stated; while the second part, caused by refraction, gains in importance.
Consequently the average distance between the components of K,
increases, and, at the limb, becomes equal to that between «d, and
d,. The bright components are not interrupted there by dark patches,
as elsewhere on the disk, because at the limb the strongly scattered
waves always enhance the brightness.
The influence of the two little tops of the R,-curve, whieh on the
middle of the disk determined the A,-line, has disappeared near the
limb; hence A, is wider than at the centre. Moreover, the displace-
ments of A, and K, to the red and the violet respectively have
gradually decreased on approaching the limb; for they depended on
the asymmetry of the little tops. The points d, and d,, determining
the average places of the components of /Y, at the limb, are situated
at equal distances from the real absorption line.
§ 6. Weak points of the new and of the old explanation.
While, all in all, these conclusions drawn from the dispersion
theory show a very close agreement with the results of the obser-
vations, we should by no means neglect to pay due attention to the
points where discordance exists or seems to exist. Only if searching
for defects, one has a chance to improve one’s views.
So we must notice that, if scattering and irregular refraction
determine the phenomenon, we have some reason to expect asym-
metry of kK, near the limb; and if we were right in assuming the
( 19708)
absolute value of 2—1 to be greater at d, than at d,, the red
component should be a little stronger than the violet one. St. Joun,
however, states"): “On the plates 1 mm. from the limb the emission
components are very broad and strong, and, as far as the eye can
judge, symmetrical’. But on measuring the 2width of the components
on some 30 selected plates, he found the violet one on the average
0,0074 A wider than the red one. Surely the difference is small, but
if it proves to be genuine, not accidental, our theory cannot, in its
present form, explain the phenomenon — unless we are just here
perhaps concerned with the case of asymmetry of the dispersion
curve, treated of in § 3 of my former communication *).
Another case in which our theory perhaps falls short, is the
following.
From published reproductions of spectrograms, obtained at Meudon
and on Mount Wilson, I get the impression that the average distance
between the brightest places of the A’,-components is greater at the
limb than on very bright floceuli and faculae situated e.g. halfway
between centre and limb. Now, according .to our explanation, the
position of the brightest patches of the components ought to be almost
entirely determined by the position of the points d, and d,, also in
the spectrum of those brightest floceuli, because the part of the
brightness which is due to the small intermediate tops of the R,-curve
is relatively slight in flocculi. That is: we should expect A, in the
spectrum of very bright floceuli and faculae to be on the average
not less wide than at the limb’*). If the study of original plates
confirms our suspicion that in this case the results of the observation
contradict the theoretical conclusions, we shall have to correct the
theory, or, if that is impossible, to reject it.
Finally attention must be called to some consequences resulting
from the explanation given by DrsLtanpres, JEWELL and Sr. Jonn of
the phenomena exhibited by the H and & lines.
Among the greatest difficulties into which we are led by ascribing
the line-displacements in question to ascending and descending currents,
is in my opinion the one, already mentioned in the beginning of this
paper: How is it possible, that in those violent vertical hurricanes
of calcium vapour prevailing over the general surface of the sun,
other gases of the chromosphere are not involved at all?
1) Sr. Joun. |. c. p. 54.
2) Proc. Roy. Acad. Amsterdam, XIII, 885, (1911).
’) In making the measurements, from which the gradual increase in width of
K, and Ks on approaching the limb has been deduced, St. Jonn intentionally
avoided the brillant facular sand floccular regions. Cf. I.c. p. 48 and 50.
({ 1273 )
Besides, the question arises, what can be the nature of the forces,
giving such velocities to the co-existing rising and falling currents,
and acting especially on ca/ciwm, not, or at least in a much. lesser
degree, on other gases? Some additional hypothesis is badly wanted
here.
There are more difficulties, that one cannot avoid without intro-
ducing special hypotheses. The widening of A, towards the limb is
explained by the continuous increase of the depth of the layer of
radiating calcium vapour in the line of sight on approaching the
limb. It is supposed that a sensible part of the beam of calcium-
light, reaching the observer, has been able to travel a distance of
16000—62000 kilometers ') in a nearly straight line through a layer
of the selectively absorbing solar gases, in which the average pres-
sure is evaluated at one (terrestrial) atmosphere *). This conception
seems to be opposed to the generally accepted theory of scattering
and absorption of light. Moreover, one would expect, on the basis
of the same explanation, to find the absolute brightness of A, in-
creasing in passing from the centre to the limb. This, however, does
not come true. Only in comparison with the neighbouring parts of
the spectrum, A, increases in importance, but its absolute brightness
decreases decidedly. In order to obtain spectrograms of nearly equal
photographic density, Sr. Jonn had to make the exposures 4 to 5
times longer at the limb than at the centre. The current explanation
of the phenomena therefore requires the indication of an additional
agent or process, by which the radiation of the chromosphere,
although supposed to increase in passing from the centre to the
limb, appears to decrease. One might e.g. assume the existence of
a medium, surrounding the chromosphere in a rather thin layer,
and having the property of absorbing all kinds of light in a certain
degree
Similar additional hypotheses need not be introduced, if we explain
the phenomena, exhibited by the calcium lines in the spectrum of
the various parts of the solar disk, by means of the theory of the
propagation of light through extensive masses of gas.
p. 66.
2s
1) Sr. Joun, |. ¢.
lic. p. 43.
2) Sr. Joun,
( 1274 )
Physics. “Further caperiments with liquid helium. C. On the
change of electric resistance of pure metals at very low tein-
peratures etc. IN. The resistance of pure mercury at helium
temperatures.” By Prof. H. KAMERLINGH OnNEs. Communication
N°. 120° from the Physical Laboratory at Leiden.
§ 1. Introduction. Since the appearance of the last Communi-
cation dealing with liquid helium temperatures (December 1910
liquid helium has been successfully transferred from the apparatus
in which it was liquefied to another vessel connected with it, in
which the measuring apparatus for the experiments could be immer-
sel — in fact, to a helium cryostat. The arrangements adopted for
this purpose which have been found to be quite reliable will be
deseribed in full detail in a subsequent Communication. In the
meantime there is every reason for the publication of a preliminary
note dealing only with the results of the first measurements made
with this apparatus, in which I have once more obtained invaluable
assistance from Dr. DorsmMan and Mr. G. Horst. These results confirm
and extend the conclusions drawn from the previous experiments
upon the change with temperature of the resistance of metals.
Moreover, it was, in the first place shown that liquid helium is an
excellent insulator, a fact which had not hitherto been specifically
established. This was of importance since the resistance measurements
were made with naked wires, a method that is permissible only
if the electrical conductivity of the liquid helium is inappreciable.
§ 2. The resistance of gold at helium temperatures. In the second
place a link in the chain of reasoning which I adopted in § 3 of
Communication N°. 119% to show that the resistance of pure gold
is already inappreciable at the boiling point of liquid helium has
been put to the test by determining the resistance in liquid helium
of the gold wire Awjj;, which was then estimated by extrapolation
on the analogy of the platinum. measurements. Within the limits of
experimental error, which are indeed greater for the present experiment
than was the case for the others, that value is now supported by
direct measurement. The conclusion that the resistance of pure gold
within the limits of accuracy experimentally obtainable vanishes at
helium temperatures is hereby greatly strengthened.
§ 3. The resistance of pure mercury. The third most important
determination was one of the resistance of mereury. In Communi-
oy
( 1275 )
cation N°. 119 a formula was deduced for the resistance of solid
mercury; this formula was based upon the idea of resistance vibra-
tors, and a suitable frequency vr was ascribed to the vibrators wich
makes By» = a= 30 (8 = Prancr’s number 4.864 « 10-1"). From
this it was concluded :
1. That the resistance of pure mereury would be found to be
much smaller at the boiling point of helinm than at hydrogen tempe-
ratures, although its accurate quantitative determination would still
be obtainable by experiment; 2. that the resistance at that stage
would not yet be independent of the temperature, and 3. that at
very low temperatures such as could be obtained by helium evaporating
under reduced pressure the resistance would, within the limits of
experimental accuracy, become zero.
Experiment has completely confirmed this forecast. While the resist-
ance at 13°.9 K is still 0.034 times the resistance of solid mercury
extrapolated to O°C. at 4°.3 K, it is only 0.0013, while at 3° K it
falls to less than 0.0001.
The fact, experimentally established, that a pure metal can be
brought to such a condition that its electrical resistance becomes zero,
or at least differs inappreciably from that value, is certainly of itself
of the highest importance. The confirmation of my forecast‘) of this
behaviour affords strong support to the opinion to which I had been
led that the resistance of pure metals (at least of platinum, gold,
mercury, and such like) is a function of the PLanck vibrators in a
state of radiation equilibrium. (Such vibrators were applied by
ErnstrIn to the theory of the specific heats of solid substances, and
by Nernst to the specific heats of gases).
With regard to the value of the frequency of the resistance vibrators
assumed before (one could try to obtain frequencies from resistances)
it is certainly worth noting that the wave-length in vacuo which
corresponds with the period of the mercury resistance vibrators
is about 0.5 mm., while Ruspens has just found that a mercury lamp
emits vibrations of very long wave-length of about 0.3 mm. In this
Way a connection is unexpectedly revealed between the change with
the temperature of the electrical resistance of metals and their long
Wave emission.
The results just given for the resistance of mercury are, since they
are founded upon a single experiment, communicated with all reserve.
1) In connection with its deduction it is to be noted that the gold-silver thermo-
element bebaved in liquid helium quite so as the experiments in liquid hydrogen
(Kameruincu Onaes and Cray, Comm. N’. 107) made expect.
( 1276 )
While | hope to publish a more detailed deseription of the investi-
eation which has led to these results in the near future, and while
new experiments are being prepared, which will enable me to attain
a greater degree of accuracy, it seemed to me desirable to indicate
briefly the present position of the problem ').
1, That this is justified is apparent from important papers which I have just
received as this goes to press; in one Nernst extends the investigation referred
to in Comm. N”. 119 of the specific heats and is also independently led to assume
a connection between the energy of vibrators and electrical resistance, and in the
other this hypothesis is further developed by Lixpemann.
BRR AN As
In the Proceedings of the Meeting of March 25, 1911.
p. 1087 1. 4 from the top: for these read the very small
a6 ait a , follow ,, differ from those
gat a 1g 2) US me! » 104 7 LOS
MIDS AL xs, is 3 1019.00) 4 32:86
al eee >» bottom. CE2D ~ 55 ies
5 AUS) 20.18
re Be 3 is 3 0.264 ,, 0.279
(May 26, 1911)
CONTENTS,
ABSORPTION (Selective) and anomalous scattering of light in extensive masses of gas. SSI,
ABSORPTION of water (The mechanism of the) by the seeds of the Cucurbitaceae. 542.
ABSORPTION LINES (The magnetic separation of) in connection with sun-spot spectra
2nd part. 35. 3rd part. 162.
ACETALDEHYDE-aLCOHOL (On the system:). 329.
aiR- and ricebacteria (Acetifying) the cause of Polvneuritis gallinarum. 904.
AIR-LAYERS (Preliminary report upon the investigation of the upper) begun at Batavia
in 1909. 149.
ALDEHYDE (On the unary tri molecular pseudo-ternary system: Acet-, par- and met-). 318.
ALKALI- and earthalkali metals (The permeability of red-blood-corpuscles in physio-
logical conditions, especially to). 258. 489. 927.
ALKALOID CONTENT (On the) in the leaves of the Cinchonas. 210.
ALLOTROPY (Confirmations of the new theory of the phenomenon of). [. 822,
ALUMINIUM CHLORIDE (The synthesis of as. heptachloropropane from tetrachloro-ethylene
and with the co-operation of), 685.
AMINO- and Ureopropylene-Uréine. 623.
AMSTEL (Miss. J. vAN) and G. van Iverson Jr. The temperature optimum of
physiological processes. 227. 598.
ANaLysis {On a method for the quantitative) of ternary mixtures. 429,
Anatomy. C. T, van Vaukensure: “Nucleus facialis, nucleus trigeminis posterior,
nucleus trochlearis posterior”. 143.
— L. Bork: “On the development of the Hypophysis of primates especially of
Tarsius”, 660,
—. W. G. Huer: “Notes on the trochlear and oculomotor nuclei and the trochlear
root in the lower vertebrates”. 897.
— J.J. L. D. Baron van Horvenu: “Remarks on the reticular cells of the oblongata
in different vertebrates”. 1047.
antuine (The nitration of) and of some anilides, 956.
aNIMALs (About exchange of gases in cold-blooded) in connection with their size. 48.
ARGON (Remarks on the preparation of). 54.
— (Vapour-pressures above — 140° C. critical temperature and critical pressure
of). 54.
84
Proceedings Royal Acad. Amsterdam. Vol. XIII.
I O10 NTE N Ts
ARGON (Coexisting liquid and vapour densities of). 607.
— (Calculation of the critical density of), 607.
— (Isotherms of) between +- 20° C. and —- 150° C. 614.
— (The behaviour of) with regard to the law of corresponding states. 1012.
ARISZ (Ww. H.) On the connection between stimulus and effect in phototropic curvatures
of seedlings of Avena sativa, 1022.
ARTERIAL WALL (An attempt at estimating the). 1181.
AS. HEPTACHLOROPROPANE (The synthesis of) from tetrachloro-ethylene and chloroform
with the co-operation of aluminium-chloride, 685.
Astronomy. A. PANNeKOogK: “Researches into the structure of the galaxy”. 239.
AVENA sativa (On the connection between stimulus and effect in phototropie curva-
tures of seedlings of). 1022.
AXIAL-ANGLE (On the determination of the optic) from the extinction-angle with regard
to the trace of a discretional plane in a discretioval crystal-section. 1035.
BACTERIA (Fat-splitting by). 667.
BACTERIAL acTION (Pigments as products of oxidation by). 1066,
Bacteriology. J. H. F. Kouusrucce: “Acetifying air- and ricebacteria the cause of
Polyneuritis gallinarum”. 904,
BAKHUYZEN (E. F. VAN DE SANDE) presents a paper of Dr. A, PANNEKOEK: “Researches
into the structure of the galaxy”. 239.
BALIK PAPAN BAY (East Coast of Borneo) (On Orbitoides in the neighbourhood
of the). 1122.
BARENNE (J. G. DUSSER DE) v. Dusser DE BARENnNeE (J. G.)
BATAVIA (On the semi-diurnal lunar tide as deduced from records of the astatic seis—
mograph at). 17.
— (Preliminary report upon the investigation of the upper air-layers begun at) in
1909. 149.
BEMMELEN (W. vaN) and C, Braak. Preliminary report upon the investigation
of the upper air-layers begun at Batavia in 1909. 149.
BERESTEYN (M. H. VAN). On the application of Darwin’s method to some com-
pound tides. 530.
BERGANSIUS (fF. L.). A new accurate formula for the computation of the self-
inductance of a long coil wound with any number of layers. 917.
BETH (a. J. E.) The oscillations about a position of equilibrium where a simple
linear relation exists between the frequencies of the vibrations. 742.
BEIJERINCK (M. w.) presents a paper of Miss J. van Amsten and G. van ITpr-
son gR.: “The temperature optimum of physiological processes”. 227.
— presents a paper of Prof. A. W. Nreuwenuurs: “Individuality and heredity in
a lower mould fungus Trichophyton albiscicans.” 550.
— presents a paper of Prof. A. W. Nimuwennurs: “Method to cultivate micro-
organismsifrom one cell”. 566.
— presents a paper of Dr. N. L. SéHneen: “Fat-splitting by bacteria.” 667.
— Pigments as products of oxidation by bacterial action. 1066.
— presents a paper of Dr. N. L, Séunazn: “Lipase produced by microbes”. 1200.
CON TEN TS. Itl
BEI) ERINCK (M. W.) An experiment with Sarcina ventriculi”. 1237.
BINARY MIXTURES (Isotherms of monatomic gases and their). [V. Remarks on the
separation of argon. V. Vapour pressures above —140° C. critical temperature
and critical pressure of argon. 54 VI. Coexisting liquid and vapour densities of
argon; calculation of the critical density of argon 607. VIL. Isotherms of argon
between + 20° C. and —150° C. 614. IX. The behaviour of argon with regard
to the law of corresponding states. 1012.
BINARY SYsSTEM*(On the continuous connection between the threephase lines which
indicate the equilibria between the two components in the solid condition with
liquid and vapour, respectively in a). 158.
BINARY sysTeMs (The equilibrium solid-liquid-gas in) which present mixed crystals.
2nd communication. 206.
— (On vapour-pressures in) with partial miscibility of the liquids. 865. Adden-
dum. 957.
BLastocyst (The Eutherian and the Matherian early). 1077.
BLOOD-corPuscLes (The permeability of red) in physiological conditions, especially
to alkali- and earth-alkali metals. 258. 489. 927.
BLOOD-PRESSURE (A new method of determining the arteriz]) in man; at the same
time an attempt at estimating the influence of the arterial wali on it, 1'S1.
BOEKE (J.) and K, W. Dammerman. The saccus vasculosus of fishes a receptive
nervous organ and not a gland. 186.
BOEREMA (J.) and H. Haca. The electromotive force of the Weston normal cell. 587.
BOESEKEN (J.) and H. J. Prins. The synthesis of as. hepfachloropropane from tetra-
chloro-ethylene and chloroform with the co-operation of aluminium chloride. 685.
BOESEKEN (J.) and A. Scuweizer. The velocity of the ring opening in connection
with the composition of the unsaturated ring systems. 534.
BOIS (H. E. J. G. DU) An improved semicircular electromagnet. II. 386. ’
— presents a paper of Dr. G. J. Extas: “On the Zeeman-eflect for emissionlines
in a direction oblique with regard to the lines of force”. 391.
BOLK (L.) presents a paper of Dr. C. T. van Vatkensure: “Nucleus facialis dorsalis,
nucleus trigeminis posterior, nucleus trochlearis posterior”. 143,
— On the development of the Hypophysis of primates especially of Tarsius. 660.
— presents a paper of Dr. W. G. Hurr: “Notes on the trochlear and oculomotor
nuclei and the trochlear root in the lower vertebrates.” 897.
— presents a paper of Dr. J. J. L. D. Baron van HoEveELL: “Remarks on the
reticular cells of the oblongata in different vertebrates”. 1047.
BONNEMA (J. H.) Diluvial boulders from the island of Borkum. 137.
BOOLE stor? (Mrs, a.) and P. H. Scnourr. Reciprocity in connexion with
semiregular polytopes and nets. 384.
BORKUM (Diluvial boulders from the island of). 137.
Botany. C. van Wissetincn: “On the structure of the nucleus and karyokinesis in
Closterium Ehrenbergii Men”. 365.
— A. A. L, Rurcers: “The influence of temperature on the presentation time in
geotropism”. 476.
84
IV CON TEN TS,
Botany. Ep. Verscnarrent: “The cause determining the selection of food in some
herbivorous insects”. 536.
— Bp. Verscnarrenr: “The mechanism of the absorption of water by the seeds
of the Cucurbitaceae, 542.
— H.H. Zeyrstra Fax.: “On the cause of dimorphism in Oenothera nanella”. 680.
— W. H. Arisz: “On the connection between stimulus and effect in phototropic
curvatures of seedlings of Avena sativa”. 1022.
BRAAXK (c.) On the determination of the epicentre of earth-quakes by means of records
at a single station. 11.
— On the semi-diurna! lunar tide as deduced from records of the astatic seismo-
graph at Batavia. 17.
— On tidal forces as determined by means of WrEciERt’s astatic seismograph. 1231.
BRAAX (c.) and W. van BemMecen. Preliminary report upon the investigations of
the upper air-layers begun at Batavia in 1909, 149.
BROUWER (tu. &. J.) On continuous vector distribution on surfaces. 3rd Communi-
cation. 171.
— Continuous transformations of surfaces in themselves. 3rd Communication. 767.
BUBANOVIc (k.) and I]. J. Hampurcer. The permeability of red bloodeorpuscles
in physiological conditions, especially to alkali- and earth-alkali metals. 258.927.
BuBANovViIc (f.), H. J. Hampurcer and J. pe Haan. On the influence of iodoform,
chloroform and other substances dissoluble in fats, on phagocytosis. 952.
BUCUNER (&. H.) Investigations on the radium content of rocks. I. 359. If. 818.
BUYTENDIJJK (8. J. J.) About exchange of gases in cold blooded animals in connection
with their size. 48.
— On the consumption of oxygen by the nervous system, 577.
— On the negative variation of the nervus acusticus caused by a sound. 649.
catcium (The influence of small amounts of} on the motion of phagocytes. 66.
CANNEGIETER (H. G.). Ionization of gases by light emitted from Ge1ssLeR tubes.
1114.
Chemistry. F. E. C. Scuerrer: “On the appearance of a maximum and minimum
pressure with heterogeneous equilibria at a constant temperature”. 31.
— F. E. ©. Scnerrer: “On the continuous connection between the three-phase
lines which indicate the equilibria between the two components in the solid
condition with liquid and vapour respectively, in a binary system”. 158.
— H. R. Kruyr: “The equilibrium solid-liquid-gas in binary systems which present
mixed crystals” 2nd Communication. 206.
— P. van Lerrsum: “On the alkaloid content in the leaves of the Cinchonas”. 210.
— A. Sirs and H. L. pe Lenuw: “On the unary trimolecular pseudo-ternary
system acet-, par-, and met-uldehyde”. 318.
— A. Surrs and H. L. pp Leeuw: “On the system: acetaldehyde-alcohol”. 329,
— A. Smrrs and W. J. pe Mooy: “On the system: chlorine-sulphurdioxyde”. 339,
— A. Smrrs: “On critical end-points in ternary systems”. 342. '
— Apa Prins: “Critical phenomena of the ternary system: ether-anthraquinone-
naphthalene”. 353.
CONTENTS. wv
Chemistry. E. H. Bécuner: “Investigations on the radium content of rocks”. [. 359.
IL. 818.
— A. F. Houtemax, T. van per Linpen and J. J. P. Vanreron: “On a method
for the quantitative analysis of ternary mixtures”. 429.
— J. J. P. Varero=: “The melting diagram of the system of the three isomeric
uitranilines”. 429.
— A. F. Hotteman and [. J. Rinkes: “On the introduction of halogen atoms
into the core of phenols”. 429.
— A. F. Hotteman and T. van per Linpen: “On the introduction of halogen
atoms into the core of the monohalogen benzols’’. 429.
— A. P. N. Francuimont: “On nitrogen (or nitrilo)-trimethylnitraminomethylene”.
527.
— J. Boksexen and A. Scuweizer: “The velocity of the ring opening in connection
with the composition of the unsaturated ring systems”. 534.
— A. P. N. Francutmoxr and J. V. Dussky: “On the reaction products of
potassium isoeyana‘e and diaminoacetone hydrochloride. Amino- und ureopro-
pylene-uréine”’. 625.
— J, Bogsexen and Il. J. Prins: “The synthesis of as. heptachloropropane from
tetrachloro-ethylene and chloroform with the co-operation of aluminium chloride”.
685.
— A. F. Houueman and J. M. Stornouwer: “On the three isomeric fluorobenzenes
and some of their derivatives”. 71S.
— P. van Rompurci: “On the action of nitrous acid on dinitro dialkyl-aniline”. 820.
— A. Smirs and H. L. pe Leeuw: “Confirmations of the new theory of the
phenomenon of allotropy”. I. 822.
— F. E. ©. Scuerrer: “On the determination of three phase pressures in the
system hydrogen su'phide + water”. 829.
— A. F. Honueman, J. C. Harrocs and T. van per LInvEN: “The nitration of
aniline and of some anilides”. 956.
— F. A. H. Scurersemakers: “Equilibria in the system: Water-Sodium sulphate-
Sodium chloride-Copper sulphate-Cupric chloride”. 1163.
— P. van Rompurcu: ‘“Hypaphorine and the relation of this substance with
tryptophane’’. 1177.
CHLORIDE OF cCaLciUM (On the stimulating effect of) and of intestinal mucous mem-
brane extract on the action of trypsin. 1002.
CHLORINE-sulphurdioxyde (On the system). 329.
cHLoRoFoRM (The synthesis of as. heptachloropropane from tetrachloro-etlylene and)
with the co-operation of aluminium chloride, 685.
— (On the influence of iodoform), and other substances dissoluble in fats, on
phagocytosis. 982.
cincuonas (On the alkaloid content in the leaves of the). 210.
CLOSTERIUM EHRENBERGII MEN. (On the structure of the nucleus and karyokinesis in), 365.
COEXISTING PHASES (Some remarks on the value of the volumes of the) of a simple
substance. I, 1253.
v1 boNt BARDS,
cor. (A new accurate formula for the computation of the self-inductance of a long)
wound with any number of layers. 917.
compLeses of revolution (Quadratic) and congruences of revolution. 1084.
CONGRUENCES of revolution (Quadratic complexes of revolution and). 1084,
conics in space (On a system of). 762.
CRITICAL QUANTITIES (On the value of the). 1211.
CROMMELIN (c. a.). Isotherms of monatomic gases and their binary mixtures.
[V. Remarks on the preparation of argon. V. Vapour pressures above — 140°C.
Critical temperature and critical pressure of argon. 54. VI. Coexisting liquid and
vapour densities of argon; caleulation of the eritical density of argon. 607.
— and II. Kameritincu Oxxes. Isotherms of monatomic gases and of their binary
mixtures, VII. Isotherms of argon between + 20° C. and — 150°C.” 614. IX.
“The behaviour of argon with regard to the law of corresponding states.” 1012.
Crystallography. J. Scumvrzer: “On the orientation of microscopic crystal-sections ’. 720.
— J. Scumurzer: “On the orientation of crystal-sections.” 1031.
— J. Scumurzer: “On the determination of the optic axial-angle from the extinction-
angle with regard to the trace of a discretional plane in a discretional crystal-
section”. 1035,
-— J. Scumutzer: ‘On the determination of an unknown plane from its traces in
two orientated crystal-sections.” 1045,
CRYsTAL-SFCTION (On the determination of the optic axial-angle from the extinction-
angle with regard to the trace of a discretional plane in a discretional). 1035.
CRYSTAL-SECTIONS (On the orientation of microscopic). 720.
— (On the orientation of). 1031.
— (Gn the determination of an unknown plane from its traces in two orientated). 1045.
crysraLs (The equilibrium solid-liquid-gas in binary svstems which present mixed).
2nd Communication. 206.
cubic surrace (On the relation between the vertices of a definite six dimensional
polytope and the lines of a). 375.
cucuRBITACEAE (The mechanism of the absorption of water by the seeds of the). 542.
cuLrures (Pure) from a single cell, isclated under the microscope. 840.
curve (On linear polar groups belonging to a biquadratic plane). 44.
DAMMERMAN (k. w.) and J. Boeke, The saccus vasculosus of fishes a receptive
nervous organ and not a gland. 186.
DARWIN’s method (On the application of) to some compound tides. 530.
Density of argon (Calculation of the critical). 607.
DERMATOMERY (A contribution to the) of the hind leg in dogs. 1146.
peRRID (On the physiological effects of). 688.
DIAMETER (Rectilinear) for oxygen. 939.
DIAMINOACETONE HYDROCHLOBIDE (On the reaction products of potassium isoevanate
and). 625.
DIFFERENTIAL EQUATIONS (On the centra of the integral curves which satisfy) of the
first order and the first degree. 1241.
aaa
CONTENTS. Vil
DILUViAL BoULDERs from the island of Borkum. 137.
DIMORPHISM (On the cause of) in Oenothera nanella. 680.
DINITRODIALKYI-ANILINES (On the action of nitrous acid on). 820.
DISPERSION of light (Observations concerning anomalous) in gases. 1088.
DISSOLUTION of mixtures (The critical phenomena of) with normal components examined
under variable pressure. 507.
pocs (Experimental researches on the segmental innervation of the skin in). 6th Com-
munication. 270. 7th Communication. 431.
— (A contribution to the dermatomery of the hind leg in). 1146.
DOUBLE POINTS of a c, of genus 0 or 1. 629.
DUBSKY (a. v.) and A. P. N. Francuimonv. On the reaction products of potassium
isocyanate and diaminoacetone hydrochloride. Amino- and ureopropylene-
uréine. 625.
DUSSER DE BARENNE (J. G.). The action of strychnine on the central nervous
system. The segmental, strictly localized strychniue-intoxication of the dorsal
spinal mechanisms; a contribution to the dermatomery of the hind leg in dogs. 1146.
EARTH -ALKALT METALS (Ile permeability of red blood-corpuscles in physiological
conditions, especially to alkali- and). 258. 489. 927.
EARTH QUAKES (On the determination of the epicentre of) by means of records at a
single station. 11.
EFFECT (On the connection between stimulus and) in phototropic curvatures of seed-
lings of Avena sativa. 1022.
ELECTROMAGNET (An improved semicircular) II. 386.
ELECTROMCTIVE FORCE (lhe) of the Weston normal cell. 587.
ELIAS (G. J.). On the ZeemaN-eflect for emission-lines in a direction oblique with
regard to the lines of force. 391.
EMISSION-LINFS (On the Zeeman-etlect for) in a direction oblique with regard to the
lines of force. 391.
EMMETROPISATION (lens measurements and). 446.
END-PoINis (On critical) in ternary systems. 342.
EQuUABRIA (On the appearance of a maximum and minimum pressure with hetero-
geneous) at a constant temperature. 31.
— (On the continuous connection between the three-phase lines which indicate the)
between the two components in the solid condition with liquid and vapour res-
pectively, in a binary system. 158.
— in the system: Water-Sodium sulphate-Sodium chloride-Copper sulphate-Cuprie
chloride. 1163.
EQUILIBRIUM (The oscillations about a position of) where a simple linear relation
exists between the frequencies of the vibrations. 742.
— solid-liquid-gas (The) in binary systems which present mixed crystals. 2nd
Communication. 203,
ERRATUM. 310, 491, 1119, 1276.
ETHER-anthraquinone=-naphthalene (Critical phenomena of the ternary system) 353,
EUTHERIAN (The) and the Matherian early blastocyst. 1077.
Vill CON TEN Ts,
LNTINCTION-ANGLE (On the determination of the optic axial angle from the) with
regard to the trace of a diseretional plane in discretional crystal-section. 1085.
FAT SPLIDTING by bacteria. 667.
risuirs (The saccus vaseulosus of) a receptive nervous organ and not a gland. 186.
— (A new case of parental care among). 583.
rtora of Tegelen (A further investigation on the pliocene). 192.
FLUOROBENZENES (On the three isomeric) and some of their derivatives. 718.
FRANCHIMONT(A. P.N.). On nitrogen (or nitrilo) — trimethylnitraminomethylene. 527.
— and J. v. Dusky. On the reaction products of potassium isocyanate and diami-
noacetone hydrochloride. Amino- and ureopropylene-uréine.” 625.
FREDHOLM (On the integral equation of). T34.
FUNCTIONS (Infinitesimal iteration of reciprocal). 21, 284 part 202.
ruxcus Trichophyton albiscicaus ({ndividuality and heredity in a lower mould). 550.
GALL\XY (Researches into the structure of the), 239.
Gas (Determination of the pressure of a) by means of Gipes’ statistical mechanics. 135.
— (Selective absorption and anomalous scattering of light in extensive masses of). 881.
Gases (About exchange of) in cold blooded animals in connection with their size. 48.
— (Isotherms of monatomic) and their binary mixtures. IV. Remarks on the
separation of argon. V. Vapour pressures above —140°C, critical temperature
and critical pressure of argon, 54. VI, Coexisting liquid and vapour densities of
argon; calculation of the critical density of argon. 607. VII. Isotherms of argon
between + 20° C. and —150° C, 614.
— (Observations concerning anomalous dispersion of light in). 1st Communication.
10S8.
— (lonization of) by light emitted from GrissLEr tubes. 1114.
GE1SSLER TuBEs (Lonization of gases by light emitted from). 1114.
Geology. J. H. Bonnema: “Diluvial boulders from the island of Borkum”. 137.
— L. Rurren: “On Orbitoides in the neighbourhood of the Balik Papan bay (East-
coast of Borneo)”. 1122.
Geophysics. C. Braax. “On the determination of the epicentre of earth-quakes by
means of records at a single station”. 11.
— C. Braakx: “On the semi-diurnal lunar tide as deduced from records of the
astatie seismograph at Batavia”. 17.
— A. Wicumann: “On the volcanic eruption in the island of Téon (Tijau) in
1659.” 485.
— M. H. van Beresreyy: “On the application of Darwin’s method to some
compound tides”. 530.
— C. Braak: “On tidal forces as determined by means of WiecuErt’s astatic
seismograph’. 1231,
GrorropisMm (The influence of temperature on the presentation time in). 476.
G1BBs’ statistical mechanics (Determination of the pressure of a gas by means of). 135.
GODEAUX (LUCIEN). On a system of conics in space. 762.
GryNs (G.). The permeability of red bloodcorpuscles in physiological conditions,
especially to alkali- and earth alkali-metals. 489.
CHO NUDE Ne T79! 1x
Waan (J. dB), H. J. Hamsureer and F. Busanovic. Qn the influence of iodoform,
chloroform and other substances dissoluble in fats, on phagocytosis. 982,
maGa (u.) and J. Boerema. The electromotive force of the Wrsron normal cell. 587.
WaALOGEN atToOMs (On the introduction of) into the core of phenols. 429.
— (On the introduction of) into the core of the monohalogenbenzols, 429.
HAMBURGER (H. J.). The influence of small amounts of calcium on the motion
of phagocytes. 66.
— presents a paper of Mr, E. Hexma: “On the stimulating effect of chloride of
calcium and of intestinal mucous membrane extract on the action of trypsin”. 1002.
— and F. Busanovic. The permeability of red blood-corpuscles in physiological
conditions, especially to alkali- and earth-alkali metals. 258. 927.
—, J. pE Haan en F. Bousanovic. On the influence of iodoform, chloroform, and
otber substances dissoluble in fats, on phagocytosis. 982.
HARTOGS (J. c.), A. F. Honteman and T. van per Linpen. The nitration of
aniline and of some anilides. 955.
HASSELT (E H. VAN). On the physiological effects of derrid. 688.
HEAT (On Nernst’ theorem of). 700.
u1EKMA (E.). On the stimulating effect of chloride of calcium and of intestinal mucous
membrane extract on the action of trypsin. 1002.
HELIUM (Further experiments with liquid). 1093. 1274.
HEREDITY (Individuality and) in a lower mould fungus Trichophyton albiscicans. 550.
HOEVELL (J. J. L. D. BARON VAN). Remarks on the reticular cells of the oblongata
in different vertebrates. 1047.
HOLLEMAN (a. F.) presents a paper of Dr. F. E. C. Scurrrer: “On the appearance
of maximum and minimum pressure with heterogeneous equilibria at a constant
temperature”. 31.
—- presents a paper of Prof. A, Smirs and Dr. H. L. pe Lezuw: “On the unary
tri-molecular pseudo-ternary system acet-, par-, and acet-aldehyde”. 318.
— presents a paper of Prof. A. Smits and Dr. H. L. pp Leruw: “On the system:
acetaldehyde-alcohol”. 329.
— presents a pauper of Prof. A. Smirs and W. J. ve Mooy: On the system
chlorine-sulphurdioxyde”. 339.
— presents a paper of Dr. Apa Priys: “Critical phenomena of the ternary system:
ether-anthraquinone-naphthalene”. 353.
— presents a paper of Dr. KE. H. Bicuner: “Investigations on the radium content
of rocks” I. 359. II. 818.
— presents a paper of Mr. J. J. P. Vateron: “The melting diagram of the system
of the three isomeric nitranilines”. 429.
— presents a paper of Prof. J. Boisrken and A. Scuweizer: “The velocity of
the ring opening in connection with the composition of the unsaturated ring
systems”. 534,
— presents a paper of Dr, ¥. E. C. Scanrrer: “On the determination of three-
phase pressures in the system: hydrogen sulphide + water”. 829.
x CONTENTS,
HOLLEMAN (a. F) and T. van per LinpEn. On the introduction of halogen atoms
into the core of the monohalogenbenzols. 429.
— and I. J. Rixkrs. On the introduction of halogen atoms into the core of
phenols, 429.
— and J. M. Snornouwer. On the three isomeric fluorobenzenes and some of
their derivatives. 718.
— J. C. Harroes and 'T. van per Linpen. The nitration of aniline and of some
anilides. 956.
— T. van per Linven and J. J. I’. Vateron. On a method for the quantitative
analysis of ternary mixtures. 429.
UMOOGEWERFF (s.) presents a paper of Prof. J. Bo&srken and Dr. H. J. Perrys:
“The synthesis of as. heptachloropropane from tetrachloro-ethylene and chloroform
with the co-operation of aluminium chloride”. 685.
HUBRECHT (a, a. W.) presents a paper of Dr. J. Borke and K. W. DamMMEekMan:
“The Saccus vasculosus of fishes a receptive nervous organ and nota gland”. 186.
— The Eutherian and the Matherian early blastocyst. 1077.
uuxEY (w. G.). Notes on the trochlear and oculomotor nuclei and the trochlear root
in the lower vertebrates. 897. a
HYDROGEN SULPHIDE -+ water (On the determination of threephase pressures in the
system:). 829.
HYPAPHORINE and the relation of this substance with tryptophane. 1177.
HyPoPitysis. (On the development of the) of primates especially of Tarsius. 660.
IMBIBITION vy. SWELLING.
INDIVIDUALITY and heredity in a lower mould fungus Trichophyton albiscicans. 550.
InsEcTs (The cause determining the selection of food in some herbivorous), 530.
INTEGRAL cuRVES (On the centra of the) which satisfy differential equations of the
first order and the first degree. 1241.
INTEGRAL EQUATION of FreDUOLM (On the). 734.
INTEGRATING of series (On the) term-by- term. 850.
INVOLUTION (A quadruple) in the plane and a triple involution connected with it. $2.
ropororM (On the influence of), chloroform and other substances dissoiuble in fats,
on phagocytosis. 982.
ISOTHERMS of monatomic guses and their binary mixtures. 1V. Remarks on the pre-
paration of argon. V. Vapour pressures above —140° C. critical temperature and
critical pressure of argon, 54. VI. Coexisting liquid and vapour densities of
argon; calculation of the critical density of argon. 607. VII. Isotherms of argon
between + 20°C. and —150°C, 614. IX. The behaviour of argon with regard
to the law of corresponding states. 1012.
ITERATION (Infinitesimal) of reciprocal functions. 21. 2nd part. 202.
ITERSON JR. (G. VAN) and Miss J. van Amsten. The temperature optimum of
physiological processes. 227. 598.
JULIUS (w. H.). Note on the interpretation of spectroheliograph results and of line-
shifts, and on anomalous scattering of light. 2.
6.0 No FON ss MT
SuLtus (Ww. u.). Selective absorption and anomalous scattering of light in extensive
masses of gas. 881.
— presents a paper of Mr. F. L. Bereanstus: “A new accurate formula for the
computation of. the self-inductance of a long coil wound with any number of
layers”. 917.
— presents a paper of Mr. H. G. Cannecierer: “Ionization of gases by light
emitted from GrissLer tubes”. 1114.
— The lines H and K in the spectrum of the various parts of the solar disk. 1263.
— and B. J. van per Puaats, Observations concerning anomalous dispersion of
light in gases, 1st Communication. 1088.
KAMERLINGH ONNES (H.) presents a paper of Mr.C. A.CromMELIN: “Isotherms
of monatomic gases and their binary mixtures. [V. Remarks on the preparation of
argon. V. Vapour pressures above —140° C., critical temperature and critical
pressure of argon”. 54. VI. “Coexisting liquid and vapour densities of argon;
calculation of the critical density of argon”. 607.
— Further experiments with liquid helium. 1093. 1274.
— and C. A. Crommexin. Isotherms of monatomic gases and of their binary
mixtures. VIL. Isotherms of argon between + 20° C. and —150° C. 614, IX.
The behaviour of argon with regard to the law of corresponding states. 1012.
— and E. Marutas. Rectilinear diameter for oxygen. 939
KAPTEYN (w.) presents a paper of Dr. M. J. van Uven: “Infinitesimal iteration
of reciprocal functions”. 202.
— On the final integral occurring in Prof. Winp’s paper: “Diffraction of a single
pulse wave by a slit, according to Kircwnorr’s theory”, 405.
— On the centra of the integral curves which satisfy differential equations of the
first order and the first degree, 1241.
— On the integral equation of FrepHoLM. 734.
KARYOKINESIS (On the structure of the Nucleus and) in Closterium Ehrenbergii Men. 365.
KATZ (J. R.). Experimental researches on the analogy between swelling (imbibition)
and mixing. 958. 975.
KIRCHUOFF’s THEORY (Diffraction of a single pulse wave through a slit according
to). 394.
— (On the final integral occurring in Prof. Winp’s paper: “Diffraction of a single
pulse wave by a slit, according to). 405,
KLUYVER (J. c.). On the integrating of series term-by-term. 850.
KOHLBRUGGE (J. H. F.). Acetifying air- and ricebacteria the cause of Polyneuritis
gallinarum. 904.
KOHNSTAMM (PH.). On osmotic temperatures and the kinetic signification of the
thermodynamic potential. 778.
— and L. S. Ornsterx. On Nernst’ theorem of heat. 700.
—and F. E. C. Scnerrrr. Thermodynamic potential and velocities of reaction.
789.
— and J. Timmermans, On vapour-pressures in binary systems with partial misci-
bility of the liquids. 865. Addendum. 957.
xt CONT EN T'S,
KORTEWEG (b. J.) presents a paper of Dr. L. EB. J. Brouwrr: “On continuous
vector distributions on surfaces”. 3rd Communication. 171.
— presents a paper of Dr. H. J. BE. Bera: “The oscillations about a position of
equilibrium where a simple linear relation exists between the frequencies of the
vibrations”. 3rd part. 742.
— presents a paper of Dr. L. E. J. Brouwer: “Continuous one-one transformations
of surfaces in themselves”. 3rd Communication. 767.
KRUYT (H. R.). The equilibrium solid-liquid-gas in binary systems which present
mixed crystals. 2nd Communication. 206.
LAAR (J. 3. VAN). On the solid state. V. 454. VI. 636.
LAw of corresponding states (The behaviour of argon with regard to the). 1012.
LEBRSUM (Pv. VAN). On the alkaloid content in the leaves of the Cinchonas. 210.
LEEUW (H. L. DB) and A. Smivs. On the unary trimolecular pseudo-ternary system:
acet-, par- and met-aldehyde. 318.
— On the system: acetaldehyde-alcohol. 329.
— Confirmations of the new theory of the phenomenon of allotropy. I. $22.
LENS-MNASUREMENTS and Emmetropisation. 446,
uignr (Note on the interpretation of spectroheliograph results and of line-shifts and
on anomalous scattering of). 2.
— (On the scattering of) by molecules. 92.
— (Observations concerning anomalous dispersion of) in gases, L088.
— (Ionization of gases by) emitted from Grisster tubes. 1114.
LINDEN (?% vaN DER) and A, F. Hoiieman. On the introduction of halogen
atoms into the core of the monohalogenbenzols. 429.
—, A. F. Horteman and J. C. Hartocs, The nitration of aniline and of some
anilides. 956.
—, A. F. Hoiteman and J. J. P. Va1Eron. On a method for the quantitative
analysis of ternary mixtures. 429.
LInE-sHIFTs (Note on the interpretation of spectroheliograph results and of) and on
anomalous scattering of light. 2
Lines (Cn the continuous connection between the three-phase) which indicate the
equilibria between the two components in the solid condition with liquid and
vapour respectively, in a binary system. 158.
— #H and K (The) in the spectrum of the various parts of the solar disk. 1263,
LIPASE produced by microbes. 1200.
11guips (On vapour-pressures in binary systems with partial miscibility of the). 865.
Addendum. 957.
LORENTZ (Ht. A.). On the scattering of light by molecules. 92.
— presents a paper of Dr. L. S. Ornzein: “Determination of the pressure of a
gas by means of Gipgs’ statistical mechanism”. 135.
— presents a paper of Mr. J. J. van Laar: “On the solid state’. V. 454.
VI. 636.
— presents a paper of Dr. L. S. Ornsrern: “Some remarks on the mechanical
foundation of thermodynamics”. I. 804. II. 858.
CoN TEN TS: XIII
LUNaR TIDE (On the semi-diurnal) as deduced from records of the astatic seismograph
at Batavia. 17.
_ MAGNETIC SEPARATION (The) of absorption lines in connection with sun-spot spectra.
2nd part. 35. 3rd part. 162.
_MAJCEN (GEORGE). On quartic curves of deficiency zero with a rhamphoid cusp
and a node. 652.
Mathematics. M. J. van Uven: ‘Infinitesimal iteration of reciprocal functions”. 21.
2nd part. 202.
— Jan pe Varies: “On linear polar groups belonging to a biquadratic plane curve”. 44.
— Jan bE Vates: “A quadruple involution in the plane and a triple involution
connected with it”. 82.
— L. E. J. Brouwer: “On continuous vector distributions on surfaces”. 3rd Com-
munication. 171.
— P. H. Scnoure: “On the relation between the vortices of a definite sixdimensional
polytope and the lines of a cubic surface”. 375.
— Mrs. A. Boote Storr and P. H. Scnoure: ‘Reciprocity in connexion with
semiregular polytopes and nets’. 384.
— W. kapreyn: “On the final integral occurring in Prof. Winp’s paper: Diffraction
of a finale pulse wave by a slit, according to KincuHorr’s theory”. 405.
~ W. van per Woupe: “Double points of a c, of genus 0 or 1”. 629.
— GEORGE MAJCEN: “On quartic curves of deficiency zero with a rhamphoid cusp
and a node.” 652.
— W. Kapreyn: “On the integral equation of Fredholm”. 734.
— H., J. E. Bera: “The oscillations about a position of equilibrium where a simple
linear relation exists between the frequencies of the vibrations”, 3rd part. 742.
— Lecien Gopkaux: “On a system of conics in space”. 762.
— I. E. J. Brouwer: “Continuous one one transformations of surfaces in themselves”.
3rd Communication. 767.
— J. C. Kuuyver: “On the integrating of series term-by-term”. 850,
— J. Wonrr: “Quadratic complexes of revolution and congruences of revolution”
1084,
— W. Kapreyn: “On the centra of the integral curves which satisfy differential
equations of the first order and the first degree”. 1241.
MATHERIAN early blastocyst (The Eutherian and the). 1077.
MATHIAs (£.) and H. Kamertincu Onnes. Rectilinear diameter for oxygen. 939.
MaxIMuM and minimum pressure (On the appearance of a) with heterogeneous equilibria
at a constant temperature. 31.
MELTING DIAGRAM (The) of the system of the three isomeric nitranilines. 429.
MEMBRANE EXTRACT (On the stimulating effect of chloride of calcium and of intestinal
mucous) on the action of trypsin. 1002.
Meteorology. W. van Bemme.en and C. Braak: “Preliminary report upon the
investigations of the upper air-layers begun at Batavia in 1909”, 149.
MicroBes (Lipase produced by). 1200,
XIV ClO NT ENS Dass
Microbiology. A. W. Nieuwennurs: “Individuality and heredity in a lower mould
fungus Trichophyton albiscicans”. 550.
— A. W. Nieuwennuts: “Method to cultivate micro-organisms from one cell”. 566-
— N. L. Séuncen: “Fat-splitting by bacteria’. 667.
— 8. L. Scnouren: “Pure cultures from a single cell, isolated under the microscope”.840,
— M. W. Beerinck : “Pigments as products of oxidation by bacterial action”. 1066.
— N. L. Séuncen: “Lipase produced by microbes”. 1200.
— M. W. Benerinck: ‘An experiment with Sarcina ventriculi”. 1237.
MICRO-ORGANISMS (Method to cultivate) from one cell. 566.
MINIMUM PRESSURE (On the appearance of a maximum and) with heterogeneous
equilibria at a constant temperature. 31.
miscrBrLiry (On yapour-pressures in binary systems with partial) of the liquids. 865.
Addendum. 957.
mixtnc (Experimental researches on the analogy between swelling (imbibition) and),
958. 975.
MOLECULE-COMPLEXES (Quasi-association or). 107. IL. 494.
MOLECULES (On the scattering of light by). 92.
MOLENGRAAFF (G. A. F.) presents a paper of Mr. Ciement Reip and Mrs.
Fieanor M. Ret: “A further investigation of the pliocene flora of Tegelen”. 192.
— presents a paper of Dr. J. H. Bonnema: “Diluvial boulders from the island
of Borkum”. 137.
MOLL (J. W.) presents a paper of Prof. C. van WisseLinca: ‘On the structure of
the nucleus and karyokinesis in Closterium Ehrenbergii Men”. 365.
— presents a paper of Prof. Ep. VerscnarFert: “The cause determining the
selection of food in some herbivorous insects’. 536.
— presents a paper of Prof. Ep. VerscnarreLt: “The mechanism of the absorption
of water by the seeds of the Cucurbitaceae”. 542.
MONOHALOGENBENZOLS (On the introduction of halogen atoms into the core of the). 429.
MooOY (Ww. J. DE) and A. Smits. On the system: chlorine-sulphurdioxyde. 339.
NERNST’ theorem of heat (On). 700.
NERVOUS SYSTEM (On the consumption of oxygen by the). 577.
— (The action of strychnine on the central). 1146.
NeRrvus acusticus (On the negative variation of the) caused by a sound. 649.
nets (Reciprocity in connexion with semiregular polytopes and). 384.
NIEUWENHUIS (a. w.). Individuality and heredity in a lower mould fungus
Trichophyton albiscicans. 550.
— Method to cultivate micro-organisms from one cell. 566.
NIPRANILINES (The melting diagram of the system of the three isomeric). 429.
NITRATION (The) of aniline and of some anilides. 956.
NITROGEN (On) (or nitrilo)-trimethylnitraminomethylene. 527.
NITROUS actD (On the action of) on dinitrodialkyl-anilines. 820.
NOYONS (a. K. M.) Physiological sclerometry. 312.
nucter (Notes on the trochlear and oculomotor) and the trochlear root in the lower
vertebrates. 897.
t=) Ae
CONTENTS. XV
NUCLEus (On the structure of the) and karyokinesis in Closterium Ehrenbergii Men. 365
— facialis dorsalis, nucleus trigemini posterior, nucleus trochlearis posterior. 143.
OBLONGATA (Remarks on the reticular cells of the) in different vertebrates. 1047.
OENOTHERA NANELLA (On the cause of dimorphism in). 680,
ORBITOIDES (On) in the neighbourhood of the Balik Papan bay (East coast of Borneo).
1122.
ORIENTATION (On the) of microscopic crystal-sections. 720.
— of erystal-sections, 1031.
ORNSTEIN (1. 8.). Determination of the pressure of a gas by means of GrBBs’
statistical mechanics. 135.
— Some remarks on the mechanical foundation of thermodynamics. I. 804. IL. 858.
— and Pu. Konnstamm. On Neryst’ theorem of heat. 700.
oscILLations (The) about a position of equilibrium where a simple linear relation
exists between the frequencies of the vibrations. 742.
OSMOTIC TEMPERATURES (On) and the kinetic signification of the thermodynamic
potential 798.
OXIDATION (Pigments as products of) by bacterial action. 1066.
OXYGEN (On the consumption of) by the nervous system. 577,
— (Reetilinear diameter for). 939.
Palaeontology. CiemEent Rerp and Mrs, Eveanor M. Rerv: “A further investigation
of the pliocene flora of Tegelen”. 192.
PANNEKOEK (a.). Researches into the structure of the gallaxy. 239.
PARENTAL CARE (A new case of) among fishes. 583.
PEKELHARING (Cc, A.) presents a paper of Mr. J. R. Karz: “Experimental researches
on the analogy between swelling (imbibition) and mixing”. 958. 975.
PERMEABILITY (The) of red blood-corpuscles in physiological conditions, especially to
alkali- and earthalkali metals. 258. 489. 927.
puacocyres (The influence of small amounts of calcium on the motion of). 56.
PHAGOCYTOSIS (On the influence of iodoform, chloroform and other substances dissoluble
in fats, on). 982.
PHENOLS (On the introduction of halogen atoms into the core of). 429.
PHOTOTROPIC CURVATURES (On the connection between stimulus and effect in) of
seedlings of Avena sativa. 1022.
Physics. W. H. Junius: ‘‘Note on the interpretation of spectroheliograph results and
of line shifts and on anomalous scattering of light”. 2.
— P. Zeeman and B. Wrnawer: “The magnetic separation of absorption lines in
connection with sun-spot spectra”. 2nd part. 35. 3rd part. 162.
— C. A. Crommein: “Isotherms of monatomic gases and of their binary mixtures,
LV. Remarks on the preparation of argon. V. Vapour pressures above — 140°C.,
critical temperature and critical pressure of argon’’. 54.
— H. A. Lorentz: “On the scattering of light by molecules’. 92.
—- J. D. van Dek Waals: “Quasi-association or molecule-complexes”. 107. IL. 494.
— L. S. Ornstern: “Determination of the pressure of a gas by means of Grpss’
statistical mechanics”, 135.
XvI CONTENTS,
Physics. H. 2. J. G. du Bois: “An improved semicircular electromagnet”. IT. 386.
— G. J. Exias: “On the Zepman-eilect for emission-lines in a direction oblique
with regard to the lines of force”. 391.
— C. H. Winn: “Ditlraction of a single pulse wave through a slit according to
Kircunorr’s theory.” 394.
— J. J. van Laar: “On the solid state”. V. 454. VI. 636.
— Jpan Timmermans: “Critical phenomena of dissolution of mixtures with normal
components examined under variable pressure”. 507.
— H. Haca and J. Borrrma’ “The electromotive force of the Wrsron normal
cell”. 587.
— C. A. Crommetin: “Isotherms of monatomic gases and of their binary mixtures.
VI. Coexisting liquid and vapour densities of argon; calculation of the critical
density of argon”. 667.
— H. Kamernincn Onnes and C. A. Crommenin: “Isotherms of monatomic gases
and of their binary mixtures. VII. Isotherms of argon between + 20° C. and
— 150° ©.” 614.
— Pu. Kounsramm and I, 8. Orxstem: “On Nernst’ theorem of heat”. 700.
— Pu. Konxstamm: “On osmotic temperatures and the kinetic signification of the
thermodynamic potential”. 778.
— Pu. Kouxstamm and F. EK. C. Scuerrer: “Thermodynamic potential and velocities
of reaction”. 789.
— L.S. Orystetn: ‘Some remarks on the mechanical foundation of thermodynamics”.
1. 604. IL. 858.
— Pu. Kounstamm and J. Timmermans: “On vapour-pressures in binary systems
with partial miscibility of the liquids”. 865. Addendum. 957.
— W. H. Juius: “Selective absorption and anomalous scattering of light in
extensive masses of gas’. 881.
— F. L. Bereansius: “A near accurate formula for the computation of the self-
inductance of a Jong coil wound with any number of layers’. 917.
— FE. Marutas and H, Kameruinca Onnes: “Rectilinear diameter for oxygen”. 939.
— H. Kameruincu Onnets and ©. A. Crommetin: ‘“Isotherms of monatomic sub-
stances and of their binary mixtures. IX. The behaviour of argon with regard to
the law of corresponding states’. 1012.
— W. H. Junius and B. J. van per Piaats: “Observations concerning anomalous
dispersion of light in gases’. 1st Communication. 1088.
— H. Kamerutnen Onnes: “Further experiments with liquid helium”. 1093. 1274.
— H. C. Cannecierer: “Ionization of gases by light, emitted from GeissLEr
tubes”. 1114.
— J. D. van per Waats: “On the value of the critical quantities”. 1211.
— J. D. van per Waats: “Some remarks on the value of the volumes of the
coexisting phases of a simple substance”. [. 1253.
— W. H. Junius: “The lines H and XK in the spectrum of the various parts of
the solar disk”. 1263.
PHYSIOLOGICAL PROCESSES (The temperature optimum of), 227, 598.
ChOUNETEE NETS: XVIL
Physiology. F. J. J. Buyrenpisk: “About exchange of gases in cold-blooded animals
in connection with their size”, 48.
— H. J. Hamsercer: “The influence of small amounts of Calcium on the motion
of Phagocytes.” 66.
— Miss J. van AmsteL and G. van Itenson Jr.: “The temperature optimum of
physiological processes”. 227. 598.
— H. J. Hamsurcer and F. Busanovic: “The permeability of red bloodcorpuscles
in physiological conditions, especially to alkali- and earthalkali metals”. 258.
— C. Wryxier and G. A. van Rigxperk: “Experimental researches on the
segmental innervation of the skin in dogs”. 6th Communication. 270. 7th Com-
munication, 431.
— A. H. M. Noyons: “Physiological sclerometry”. 312.
— W. P. C. Zeeman: “Lens measurements and Emmetropisation.” 446.
— G. Grixs: “The permeability of red bloodcorpuscles in physiological conditions,
especially to alkali- and earth-alkali metals”. 489.
— F. J. J. Buyrenpisx: “On the consumption of oxygen by the nervous system”. 577.
— F. J. J. Buyrenpiyk: “On the negative variation of the nervus acusticus caused
by a sound”. 649.
— KE. H. van Hasseur: “On the physiological effects of derrid’’. 688.
— G. van Rinperk: “Unisegmental reflex-reactions”. 715.
— H. J. Hampurcer ard F. Bupanovic: “On the permeability of red blood-
corpuscles in physiological conditions more especially to alkali- and earthalkali
metals’. 927.
— ©. Winxier: “A tumour in the pulvinar thalami optici. A contribution to the
knowledge of the vision of forms”. $28.
— J. R. Karz: “Experimental researches on the analogy between swelling (imbi-
bition) and mixing”. 958. 975.
—H. J. Hamsurcgr, J. pe Haan and F. Busanovic: “On the influence of
iodoform, chloroform and other substances dissoluble in fats, on phagocytosis’’. 982.
— E. Hexma: ‘On the stimulating effect of chloride of calcium of intestinal mucous
membrane extract on the action of trypsin”. 1002.
— J. G. Dusser DE Barenne: “The action of strychnine on the central nervous
system. The segmental, strictly localized strychnine-intoxication of the dorsal spinal
mechanism; a contribution to the dermatomery of the hind leg in dogs”. 1146.
— D. ve Vries Rerincu: “A new method of determining the arterial bloodpressure
in man; af the same time an attempt at estimating the influence of the arterial
wal] on it”. 1181.
PIGMENTS as products of oxidation by bacterial action. 1066.
PLAATS (B. J. VAN DER) and W. H. Ju.ius. Observations concerning anomalous
dispersion of light in gases. 1st Communication. 1088.
PLACE (t.) presents a paper of Dr. W. P. C, Zeeman: “Lens measurements and
Emmetropisation”’. 446.
PoLak Groups (On linear) belonging to a biquadratic plane curve. 44.
POLYNEURITIS GALLINARUM (Acetifying air- and ricebacteria the cause of). 904.
85
Proceedings Royal Acad. Amsterdam. Vol. XIIL.
XVIII CONTENTS.
ponyrorr (On the relation between the vertices of a definite sixdimensional) and the
lines of a cubic surface. 375.
POLYTOPES and nets (Reciprocity in connexion with semiregular). 354.
POTASSIUM ISOCYANATE (On the reaction products of) and diaminoacetone hydrochloride.
Amino- and ureopropylene-uréine. 625,
PRESENTATION-TIME (The influence of temperature on the) in geotropism. 476.
pressure (The critical phenomena of dissolution of mixtures with normal components
examined under variable). 507.
— of a gas (Determination of the) by means of Grps’ statistical mechanics. 135.
primatrs (On the development of the hypophysis of) especially of Tarsius. 660.
PRINS (4DA). Critical phenomena of the ternary system: ether- anthraquinone-
naphthalene. 353.
PRINS (u. J.) and J. Boksrxnn. The synthesis of as. heptachloropropune from tetra-
chloro- ethylene and chloroform with the co-operation of aluminiumchloride. 635,
PULSE WAVE (Diffraction of a single) through a slit according to Krrcunorr’s theory. 394.
— (On the final integral occurring in Prof. Wixp’s paper: “Diffraction of a single)
through a slit according to KircuHorr’s theory. 405.
PULVINAR THAL\MI opricr (A tumour in the). 928.
guaktic curves (On) of deficiency zero with a rhampoid cusp and a node. 652.
QUASI-AssocraTION or molecule-complexes. 107. II. 494.
RADIUM CONTENT (Investigations on the) of rocks. I. 359. II. 818.
REFLEX REACTIONS (Unisegmental). 715.
REID (CLEMENT) and Mrs. Exganor M. Rerp. A further investigation on the
pliocene flora of Tegelen. 192.
REILINGH (D. DE vRIEBS) v. Vries RemiNnen (D. DE)
RETICULAR CELLS (Remarks on the) of the oblongata in different vertebrates. 1047.
RICEBACTERIA (Acetifying air- and) the cause of Polyneuritis gallinarum. 904.
RING OPENING (The velocity of the) in connection with the composition of the
unsaturated ring systems. 534.
RINKEs (t. J.) and A. F, Houneman. On the introduction of halogen atoms into
the core of phenols. 42°).
rocks (Investigations on the radium content of). I. 359. IL. 818. \
ROMBURGH (b. VAN) presents a paper of Dr. H. R. Kruyz: “The equilibrium
solid-liquid-gas in binary systems which present mixed crystals”. 2nd Commu-
nication. 206.
— On the action of nitrous acid on dinitrodialkyl-anilines. 820.
— Hypaphorine and the relation of this substance with tryptophane. 1177.
RUTGERS (A. A. L.). The influence of temperature on the presentation time in
geotropism. 476.
RUTTEN (t.). On Orbitoides in the neighbourhood of the Balik Papan Bay. East-
coast of Borneo. 1122.
RIJNBERK (G. A. VAN). Unisegmental reflex-reactions. 715.
— and C, Wink.Er. Experimental researches on the segmental innervation of the
skin in dogs, 6th Communication. 270. 7th Communication. 431.
CO NTE N T's. XIX
saccus VAscuLosus (The) of fishes a receptive nervous organ and not a gland. 187.
SANDE BAKHUYZEN (E. F. VAN DE), y. BakHuyzEN (EH. FI. van DE SaNnDE).
SARCINA VENTRICULT (An experiment with). 1237.
SCATTERING oF LIGHT (Note on the interpretation of spectroheliograph results and of
line-shifts and on anomalous). 2.
— (On the) by molecules. 92.
— (Selective absorption and) in extensive masses of gas. 881.
SCHEFIER (fF. a. c.). On the appearance of a maximum and minimum pressure
with heterogeneous equilibria at a constant temperature. 3).
— On the continuous connection between the three-phase lines which indicate the
equilibria between the two components in the solid condition with liquid and
vapour respectively, in a binary system. 158.
— On the determination of three phase pressures in the system’ hydrogen sulphide
+ water. $29.
SCHEFFER (Ff, £. C.) and Pu. Kounnstama. Thermodynamic potential and velocities
of reaction. 789.
SCHMUTZER (J.). On the orientation of microscopic erystal-sections. 720.
— On the orientation of erystal sections. 1031.
— On the determination of the optic axial angle from the extinction angle with
regard to the trace of a diseretional plane in a discretional crystal-section. 1035.
— On the determination of an unknown plane from its traces in two orientated
erystal-sections. L(45.
SCHOUTE (P. H.). On the relation between the vertices of a definite sixdimensional
polytope and the lines of a cubic surface. 375.
— presents a paper of Dr. W. van DER Woupe: “Double points of a c, of genus
Ovorwi. 1629!
— presents a paper of Mr. Lucten Gopgaux: “On a system of conics in space”. 762.
— and Mrs. A. Booxe Srorr. Reciprocity in connexion with semiregular polytopes
and nets. 3$4.
SCHOUTEN (Ss. L.). Pure cultures from a single cell, isolated under the micros-
cope. 840.
SCHREINEMAKERS (Fr. a. H.). Equilibria in the system: Water-sodium sulphate-
sodium chleride-capper sulphate-cupric chloride. 1163.
SCHWEIZER (A) and J. Botsexen. The velocity of the ring opening in connection
with the composition of the unsaturated ring systems. 534,
SCLEROMETRY (Physiological). 312.
SEGMENTAL INNERVATION (Experimental researches on the) of the skin in dogs. 6th
Communication. 270. 7th Communication. 431.
SEISMOGRAPH at Batavia (On the semi-diurnal lunar tide as deduced from records
of the astatic). 17.
— (On tidal forces as determined by means of WrecueErt’s astatic). 1231.
SELECTION OF FOOD (The cause determining the) in some herbivorous insects. 536.
SELF-INDUCTANCE (A new accurate formula for the computation of the) of a long coil
wound with any number of layers. 917.
XX CONT EN TS.
okiN in dogs (Experimental researches on theesegmental innervation of the). 6th Com-
munication, 270. 7th Communication. 431.
sLOTHOUWER (J. M.) and A. I’, Horupmay. On the three isomeric fluorobenzenes
and some of their derivatives, 718. ~
sMITs (a.). On critical end-points in ternary systems. 342.
— and H. L. pp Leruw. On the unary tri-molecular pseudo-ternary system acet-,
par- and met-aldehyde. 318.
— On the system acetaldehyde-aleohol. 329.
— Confirmations of the new theory of the phenomenon of allotropy. I. 822.
— and W. J. pp Mooy. On the system: chlorine-sulphurdioxyde. 339.
SOMUNGEN (N. L.), Fat-splitting by bacteria. 667.
— Lipase produced by microbes. 1200.
soLarR pisk (The lines Z and K in the spectrum of the various parts of the). 1263.
SOLID conDITION (On the continuous connection between the three-phase lines which
indicate the equilibria between the two components in the) with liquid and
vapour respectively, in a binary system. 158.
SOLID STATE (On the). V. 454. VI. 636.
sounp (On the negative variation of the nervus acusticus caused by a). 649.
SPECTROHELIOGRAPH RESULTS (Note on the interpretation of) and of line-shifts and
on anomalous scattering of light. 2.
spectrum (The lines HZ and A in the) of the various parts of the solar disk. 1263.
SPINAL MECHANISMS (The segmental, strictly localized strychnine-intoxication of the
dorsal). 1146.
SPIRASTKELLA (Observations on the genus). 1139.
sPRONCK (Cc. H. H.) presents a paper of Dr, J. H. F. Kouupruccr: “Acetifying
air- and ricebacteria the cause of Polyneuritis gallinarum”. 904.
STIMULATING EFFECT (On the) of chloride of Calcium and of intestinal mucous mem-
brane extract on the action of trypsin. 1002.
sTrMULUs and effect (On the connection between) in phototropic curvatures of seedlings
of Avena sativa. 1022.
sTOK (J. P. VAN DER) presents a paper of Dr. C. Braak: “On the determination
of the epicentre of earth-quakes by means of records at a single station”. 1).
— presents a paper of Dr. C. Braax: “On the semidiurnal lunar tide as deduced
from records of the astatie seismograph at Batavia’. 17.
— presents a paper of Mr. M. H. van BuresreyN: ‘On the application of Darwin’s
method to some compound tides”. 530.
— presents a paper of Dr. C. Braak: “On tidal forces as determined by means of
WircHEnt’s astatic seismograph”. 123].
STRYCHNINE (The action of) on the central nervous system. 1146.
STRYCHNINE-INTOXICATION (The segmental, strictly localized) of the dorsal spinal
mechanisms; a contribution to the dermatomery of the hind leg in dogs. 1146.
suBsTaNnce (Some remarks on the value of the volumes of the coexisting phases of a
simple). I, 1253.
GUO RNY ey N ss XXxI
suBsTances (Isotherms of monatomic) and of their binary mixtures. [X. The behaviour
of argon with regard to the law of corresponding states. 1012.
SUN-SPOT sPECTRA (The magnetic appearance of absorption lines in connection with).
2nd part. 35. 3rd part. 162.
surFacks (On continuous vector distributions on). 171.
— (Continuous transformations of) in themselves. 3rd Communication. 767.
SWELLING (imbibition) (Experimental researches on the analogy between) and mixing.
958. 975.
systEM acetaldehyde-aleohol (On the). 329.
— chlorine sulphurdioxyde (On tie). 339.
— hydrogen sulphide + water (On the determination of the threephase pressures
in the). 829.
— water-sodium sulphate-sodium chloride-copper sulphate-cupric chloride (Equilibria
in they. 1163.
— of the three isomeric nitranilines (The melting diagram of the). 429.
Tarsus (On the development of the Hypophyais of primates especially of). 660.
TEGELEN (A further investigation of the pliocene flora of). 192,
TEMPERATURE (On the appearance of a maximum and minimum pressure with hetero-
geneous equilibria at a constant). 31.
— (The influence of) on the presentation-time in geotropism. 476.
TEMPERATURE OPTIMUM (The) of physiological processes. 227. 598.
TON (Lijau) (On the volcanic eruption of the island of) in 1659. 485.
TERNARY MIXTURES (On a method for the quantitative analysis of). 429.
TERNARY sysTEM (On the unary tri-molecular’ pseudo-) acet-, par- and met-aldehyde. 318.
— ether-anthraquinone-naphthalene (Critical phenomena of the). 353.
TERNARY sysTEMs (On critical end-points in). 342.
TETRACHLORO-ETHYLENE (The synthesis of as. heptachloropropane from) and chloroform
with the co-operation of aluminium chloride. 685.
THEORY (Confirmations of the new) of the phenomenon “of allotropy. [. 822.
THERMODYNAMIC POTENTIAL (On osmotic temperatures and the kinetic signification
of the). 778.
THERMODYNAMIC POTENTIAL and velocities of reaction. 789.
THERMODYNaMIcs (Some remarks on the mechanical foundation of). [. 804. IT. 858.
THREEPHASE Pressures (On the determination of) in the system hydrogen sulphide
+ water. 829.
TIDAL FoRcES (On) as determined by WrecuErt’s astatic seismograph. 1231.
rrpEs (On the application of Darwrn’s method to some compound). 530.
TIMMERMANS (JEAN). The critical phenomena of dissolution of mixtures with
normal components examined under variable pressure, 507.
TIMMERMANsS (J.) and Pu. KonnsramM. On vapour-pressures in binary systems
with partial miscibility of the liquids. 865. Addendum. 957.
TRANSFORMATIONS (Continuous one-one) of surfaces in themselves. 3™¢ Communication. 767.
TRICHOPHYTON ALBISCICANS (Individuality and heredity in a lower mould fungus). 550.
TRIMETHYLNITRAMINOMETHYLENE (On nitrogen (or nitrilo-). 527.
XXIT CONTENTS.
TROCHLEAR ROOT (Notes on the trochlear and oculomotor nuclei and the) in the lower
vertebrates. 897.
mryPsin (On the stimulating effect of chloride of calcium and of intestinal mucous
membrane extract on the action of). 1002.
TRYPTOPHANE (HHypaphorine and the relation of this substance with). 1177.
mumour (A) in the pulvinar thalami optici. A contribution to the knowledge of the
vision of forms. 928.
UREOPROPYLENE-UREINE (Amino- and). 625.
UVEN (M. J. van). Infinitesimal iteration of reciprocal functions. 21. 202.
VALETON (3. J. v.). The melting diagram of the system of the three isomeric
nitranilines. 429,
VALETON (J. J. P.), A. F. Hovnestan and T. van per Linpen. On a method for
the quantitative analysis of ternary mixtures. 429.
VALKENBURG (c. t. VAN) Nucleus facialis dorsalis, nucleus trigemini posterior,
nucleus trochlearis posterior. 143.
VAPOUR-PRESSURES above — 140° C. critical temperature and critical pressure of
argon. 54.
VAPOUR-PRESSUREs (On) in binary systems with partial miscibility of the liquids. 865.
Addendum. 957.
VECTOR-DISTRIBUTIONS (On continuous) on surfaces, 3rd Communication. 17].
VELOcITIES of reaction (Lhermodynamic potential and). 789.
VERSCHAFFELY (ED.). The cause determining the selection of food in some her-
bivorous insects. 536.
— The mechanism of the absorption of water by the seeds of the Cucurbitaceae. 542.
VERTEBRATES (Notes on the trochlear and oculomotor nuclei and the trochlear root
in the lower). 897.
— (Remarks on the reticular cells of the oblongata in different). 1047.
vertices (On the relation between the) of a definite sixdimensional polytope and the
lines of a cubic surface. 375.
visrations (The oscillations about a position of equilibrium where a simple linear
relation exists between the frequencies of). 742.
VISION OF FoRMs (A contribution to the knowledge of the). 928.
VOLCANIC ERUPTION (On the) in the island of Téon (Tijau) in 1659. 485.
VOSMAER (G.c. J.). Observations of the genus Spirastrella. 1139.
VRIES (HUGO DE) presents a paper of Mr. H. H. Zeyisrra Fzn: “On the cause
of dimorphism in Oenothera nanella.” 680.
VRIES (JAN DE) presents a paper of Dr. M. J. van Uven: “Infinitesimal iteration
of reciprocal fuuetions,” 21.
— On linear polar groups belonging to a biquadratic plane curve. 44.
— A quadruple involution in the plane and a triple involution connected with it. 82.
— presents a paper of Dr. M. J. van Uven: “Infinitesimal iteration of reciprocal
functions”. 202.
— presents a paper of Prof. Gzorce Mascen: “On quartic curves of deficiency
zero with a rhamphoid cusp and a node”. 652.
CONTENTS. XXIII
VRIES (JAN DE) presents a paper of Dr. J. Wonrr: “Quadratic complexes of
revolution anil congruences of revolution”. 1084.
VRIES RRFILINGH (Dp. DE). A new method of determining the arterial blood
pressure in man: at the same time an attempt at estimating the influence of the
arterial wall on it. 1181.
WAALS (J. D. VAN DER). Quasi-association or molecule-complexes. 107. 11. 494.
— presents a paper of Dr. F. E. C. Scurrrer: On the continuous connection
between the three phase lines which indicate the equilibria between the two com-
ponents in the solid condition with liquid and vapour respectively, in a binary
system”. 158.
— presents a paper of Prof. A. Smits : “On critical endpoints in ternary systems’. 342.
— presents a paper of Dr. Jean Timmermans: “The critical phenomena of dissolu-
tion of mixtures with normal components examined under variable pressure”. 507,
— presents a paper of Prof. Pa. Kounstamm and Dr. L.S. Ornsrein: “On Nernsv’
theorem of heat”. 700.
— presents a paper of Prof. Pa. Kounstamm: “On osmotic temperatures and the
kinetic signification of the thermodynamic potential.” 778.
— presents a paper of Prof. Pa. Kounstamm and Dr. F. EB. C. Scuerrer: “Ther-
modynamic potential and velocities of reaction”. 789.
— presents a paper of Prof. A. Smirs and Dr. H. L. ps Leow: “Confirmations
of the new theory of the phenomenon allotropy”. I, 822.
— presents a paper of Prof. Pa. Konnstamm and Dr. J. Timmermans: “On vapour-
pressures in binary systems with partial miscibility of the liquids.” 865.
— On the value of the critical quantities. 1211.
— Some remarks on the value of the volumes of the coexisting phases of a simple
substance I. 1253.
water-Sodium sulphate-Sodium chloride-Copper sulphate-Cupric chloride (Equilibria
in the system). 1163.
WEBER (MAX). A new case of parental care among fishes. 583.
WENCKEBACH (kK. F.) presents a paper of Dr. D. pe Vries Retinca: “A new
method of determining the arterial blood-pressure in man; at the same time an
attempt at estimating the influence of the arterial wall on it”. 1181.
WENT (F. A. F. C.) presents a paper of Dr. A. A. L. Ruragrs: “The influence of
temperature on the presentation-time in geotropism”. 476.
— presents a paper of Dr, S. L. Scnouren: “Pure cultures from a single cell,
isolated under the microscope’’. 840.. :
— presents a paper of Mr. W. H. Artsz: “On the connection between stimulus and
effect in phototropic curvatures of seedlings of Avena sativa”. 1022.
WESTON normal cell (The electromotive force of the). 587.
WICHMANN (a.). On the volcanic eruption in the island of Téon (Tijau) in 1659, 485.
— presents a paper of Dr. J. Scumurzer: “On the orientation of microscopic
erystal-sections’”’. 720.
— presents a paper of Dr. J. Scumurzer: “On the orientation of crystal-sections”’.
1031,
XXIV OONTENTS.
WICHMANN (a.) presents a paper of Dr. J. Scumuyznr: “On the determination
of the optic axial angle from the extinction angle with regard to the trace of a
diseretional plane in a discretional ecrystal-section”. 1035.
— presents a paper of Dr. J. Scumurzer: “On the determination of an unknown
plane from its traces in two, orientated crystal-sections’”. 1045.
— presents a paper of Mr. L. Rurren: “On Orbitoides in the neighbourhood of
the Balik Papan-bay (East-coast of Borneo)”. 1122.
WIECHERT' astatic seismograph (On tidal forces as determined by meaus of), 1231.
WINAWER (B.) and P. Zeeman, The magnetic separation of absorption lines in
connection with sun-spot spectra. 2nd part. 35. 3rd part. 162.
winp (c. 11). Diffraction of a single pulse wave through a slit aceording to Krren-
norr’s theory. 394. On the final integral occurring in this paper. 405.
WINKLER (c.) presents « paper of Prof. G. van RuNBerK: “Unisegmental reflex-
reactions”. 715.
— A tumour in the pulvinar thalami optici. A contribution to the knowledge of
the vision of forms. 928.
— presents a paper of Mr. J. G. Dusser pE Barenne: “The action of strychnine
on the central nervous system. The segmental, strictly localized strychnine-
intoxication of the dorsal spinal mechanisms; a contribution to the dermatomery
of the hind leg in dogs”. 1146.
— and G. A. van Rignperk. Experimental researches on the segmental innervation
of the skin in dogs. 6th Communication. 270. 7th Communication. 431.
WISSELINGH (c. vAN). On the structure of the nucleus and karyokinesis in
Closterium Ehrenbergii Men. 365.
WOLFP (J.). Quadratic complexes of revolution and congruences of revolution. 1084.
WOUDE (W. VAN DER). Double points of a c, of genus 0 or 1. 629.
ZEEMAN-EFFECT (On the) for emission-lines in a direction oblique with regard to the
lines of force. 391.
ZEEMAN (e.) and B. Winawer. The magnetic separation of absorption lines in
connection with sun-spot spectra. 224 part 35 3rd part. 162,
ZEEMAN (w. P. C.). Lens measurements and Emmetropisation. 446.
ZEYUSTRA FZN. (Hu. H.) On the cause of dimorphism in Oenothera nanella. 680.
Zoology. J. Borke and K. W. Dammerman: “The Saccus vasculosus of fishes a receptive
nervous organ and not a gland.” 186.
— Max Weerr: “A new case of parental7care among fishes.” 583.
— A. A. W. Husrecur: “The Eutherian and the Matherian early blastocyst”. 1077.
— G. ©. J. Vosmarr: “Observations on the genus Spirastrella’”’. 1132.
ZWAARDEMAKER (H.) presents a paper of Mr. F. J. J. Buyrenpiyx: “About ex-
change of gases in cold-blooded animals in connection with their size”. 48.
— presents a paper of Dr. A. K. M. Noyons: “Physiological sclerometry”. 312.
— presents a paper of Mr. F. J. J. Buyrenpiyx: “On the consumption of oxygen
by the nervous system”. 577.
— presents a paper of Mr, I’. J. J. BuyrenpuK : “On the negative variation of the
nervus acusticus caused by a sound”. 649.
— presents a paper of Mr. B. LH. van Hassevr: “On the physiological effects of
derrid”’. 688.
v3 ; UY
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