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THE

JOURNAL OF MICROSCOPY

AND

NATURAL SCIENCE:

THE JOURNAL OF

THE POSTAL MICROSCOPICAL SOCIETY.

BMtor :

ALFRED ALLEN,

Hon. Sec. P. M.S.

Hssociate lEMtors:

Prof. V. A. LATHAM, M.D., D.D.S., F.R.M.S., etc.,

Chicago University, U.S.A.;

J. STEVENSON BROWN, Freside?it Montreal Micro. Soc,

Montreal, Canada ;

FILANDRO VICENTINI, M.D , Chieti, Italy.

VOL. V. THIRD SERIES.
VOL XIV. OLD SERIES.

ilontion :

BAILLIERE, TINDALL, & COX, 20 KING WILLIAM ST., STRAND.
SIMPKIN, MARSHALL, HAMILTON, KENT, & Co., Limited.

Bristol :
JOHN WRIGHT & Co., STONE BRIDGE.

1895.

S^refa

cc

s

N many ways the completion of the present volume of
the International Journal of Microscopy and Natural
Science compels us to say a few words respecting it.

On glancing through the volume, we cannot but feel
a just pride in the variety and general excellence of the many
papers and articles it contains. Amongst the important contribu-
tions, the continuation of the translation of Dr. F. Vicentini's
memoir on the " Bacteria of the Sputa and Cryptogamic Flora of
the Mouth," which is completed in the present part (October),
deserves especial mention. Indeed, so well has this memoir been
received, that we intend to offer it shortly in book form ; a preface
to the work has been written by Prof. W. D. Miller of Berlin, and
Dr. Vicentini has appended a bibliography and other important
additions. The continuation of Mr. H. C. Vine's valuable papers
on the " Predacious and Parasitic Enemies of Aphides " has been
of great interest, and our best thanks are due to Mr. Vine for his
contributions. Our thanks are also due to Mr. C. D. Soar for his
papers on the " British Hydrachnid^," to Mr. W. Thomson for
his papers on " The Influence of Light on Life," and " On the
Study of the Micro Fungi," to our past-president, Mr. G. H.
Bryan, for his lucid article on "Benham's 'Artificial Spectrum Top,' "
to Mr. C. J. Watkins for his interesting contribution on " The
Denizens of an Old Cherry Tree," to Prof. V. A. Latham for the
valuable account of the " Methods and Formulae used in Examin-
ing Blood." The Presidential Addresses of Dr. H. L. Browne,
Dr. J. Hall, the Rev. E. T. Stubbs, and Dr. J. S. Turner also
deserve mention. Lastly, we must offer our best thanks for
the kind assistance we have received from so many of our
Subscribers.

lit! j LIBRARY

THE INTERNATIONAL \^

^i

JOURNAL OF MICROSCOPY & NATURAL SCIENIJE^^J^

THE JOURNAL OF THE POSTAL MICROSCOPICAL SOCIETY.

'"'■ K7i07vledge is not given us to keep, but to impart ; its worth

is lost in concealment r

[The Editor does not hold himself responsible for the views of
the authors of the papers published.]

^be 2)eni3ene of an ®lt) Cberr^ ^ree,

Mitb IRotes of its SutrouuMnge.

By C. J. Watkins. Plates I. & 11.

.^S-

ORE than twenty years ago this cherry tree — then
approaching its prime — was a convenient place to
hang the saccharine snares that allured the sweet-
loving Lepidoptera haunting our garden, which is
on a strip of Liassic clay that forms one bank of
the little river which winds its course along the
Cotteswold Valley where we have long resided.

Standing in our garden and looking up stream
we observe to the right a hilly ridge, about 700 feet
above sea level, and crowned with a wood, famous for the botanical
rarities found there and on the surrounding hills by Oade Roberts*
and his young disciple, the late Edward Newman (to whom we
owe so much for his valued labours in British Entomology), who
searched these hills and dales for floral and insect treasures, and
who, in his later years, in one of his letters to the writer, wished
to know whether the scenes of his boyhood were changed. Alas,
they are ! The noble old beech woods of our hill-sides are fast

* See Withering's British Plants, 7th Edition, 1830.

International Journal of Microscopy and Natural Science.
Third Series. Vol. V.

B

2 THE DENIZENS OF AN OLD CHERRY TREE.

disappearing, and the woodman's axe ceases not in its yearly
slaughter. Few, very few, of the old forest giants spread their
sturdy limbs, where for centuries they stood the rude shocks of
countless gales, and sheltered from the heat and storm our fore-
fathers and their herds. The owners of the soil care not about
replacing the famous fallen with young stock of the same race.
They are eager to reap in their time, so the quicker-growing spruce
and larch now stand where the grand old trees once lifted their
heads to the sky.

If our valley has been rich in floral treasures, we can point to
far more ancient stores of Nature in the wonderful Oolitic coral
reef on which the old wood we have mentioned stands. This
reef extends for miles, and we have traced it on the hills which
form the other boundary of our valley, telling us of pre-historic
times, when the old ocean beat its restless waves against the coral
shores of this inland sea, and we can imagine our hill tops bearing
those curious trees and plants peculiar to that different climate
and epoch. Even then a few kinds of insects (chiefly Neuroptera)
sported over the waters, while the Ammonites floated on the sur-
face of the waves, and the terrible Plesiosaurus, like a gigantic
swan, searched for its prey on the incoming tide.

During this changing period the rocks forming our hills were
deposited in seas rich with microscopic life, whose tiny chamber-
ed shells (Foraminifera) form a considerable portion of these vast
Oolitic limestone strata which yields to-day the famous building
freestone of this district, and the coral rag stone used for metalling
our roads and for building walls, in which we have admired many
a choice example of those wonderful organisms that once spread
their beautiful tentacles in the vast seas and lagoons on which the
eye of man never gazed !

" Frail were their frames, ephemeral their lives,
Their masonry imperishable."

To return to the present appearance of the landscape, as seen
from the bottom of our valley and looking towards the sources of
our river, we observe a hill like a promontory standing out in relief,
at whose base, the two streams forming the sources of the river,
join in one where three valleys meet, their sides ascending and
forming a series of hills, over which we have, in bygone days.

THE DENIZENS OF AN OLD CHERRY TREE. 3

spent many a pleasant hour, hunting for insects in their native
haunts, and, in the proper season, giving chase to that rarity of
our native butterflies — now, we fear, nearly extinct — the Large
Blue {LyccBna arion), king among its brethren, born amid the
bee-haunted wild thyme, whose opening flowers told us the time
to look for this coveted prize in its perfect state. To capture a
specimen sailing along before the stiff breeze (which often prevails
on these hills), one needed to excel in running to keep the insect
in view, especially when our chase extended over such rough places
and disused quarries as usually form the haunt of this species.

But our limbs are not so strong as they were in those days, and
the roads to these lovely spots are long, so we are now content to
observe those insects which are to be found nearer home ; and, if
the reader will bear with us, we will attempt to describe some of
the marvels^of insect life observed in the stump of our old cherry
tree during three months of 1893.

Some years ago this cherry tree was struck by lightning, and
soon after showed signs of decay. The limbs broke off during
the strong gales which sometimes sweep up the valley from the
Bristol Channel with terrific force ; but the stump, now only some
seven feet high and about ten inches in diameter at its base,
was left standing, as it formed a convenient post on which a metal
clothes line had been attached for years. For the last three years
signs of its being inhabited were freely shown by the numerous
particles of wood scattered from time to time on a bed of marjo-
ram growing round its base, on the leaves of which the ejected
light coloured " jaw dust " from above, showed in striking contrast
to the colour of the herb, and which induced our old gardener to
remark that the old stump was " wivvil e'ten and dakadey." We
had many times watched to see whether any insect passed in or
out of the holes from which the dust had fallen, but without suc-
cess until October 23rd, 1892, when at mid-day, in the sunlight,
we saw a black wood wasp {Femphredon) actively examining ^the
mouths of the larger burrows. Wishing to secure it for identifi-
cation, we managed to get the agile creature into a glass tube, but,
accidentally dropping the cork, our prisoner was gone in an instant.
Now, knowing what to look for, we waited and watched, and
within ten minutes we were rewarded with another visit from this

4 THE DENIZENS OF AN OLD CHERRY TREE.

determined little creature, evidently bent on some maternal cares
in the interior of the stump. Selecting a hole, it entered, but when
it emerged it was to enter again the glass prison from whence it
was transferred to the killing bottle, and now graces our collection
as one of the first specimens of Pemphredon lugubris we had taken,
although specimens of this genus had been observed, in previous
seasons, during the hottest sunshine, on the leaves of our fruit
trees, moving, with that wonderful activity of wing so characteristic
of the Fossorial Hymenoptera, to which these highly specialised
insects belong.

We now desired to remove the stump for careful examination
indoors during the winter, but business matters and ill-health pre-
vented the carrying out of our intention. However, during March,
1893, a high wind broke off the upper portion of the trunk, which
we removed indoors, and its examination brought to light such a
numerous assemblage of burrows, galleries, and tunnels, occupied
by different insects in various stages of their life histories, that,
during April, we had the stump cut down, and, after sawing it into
suitable blocks, we carefully divided each block into portions with
a strong pocket knife, and these portions, with their Hving inmates,
were put into a series of large glass-topped boxes, very special
pieces being stored in smaller boxes. The careful cutting up of
this rotten stump occupied the writer, for several hours each day,
for more than a week, but the fascinating pleasure of unveiling
these insect marvels was ample reward for any pains that may have
been taken in doing so.

The first inhabitants to attract our attention were several
Coleopterous larvae, in unstained tortuous burrows of from one-
eighth to a quarter of an inch in diameter. Fig. 2, Plate I., shows
a portion of the rotten cherry-wood with a burrow containing a
full-grown larva, and near it an active nymph or pupal form of the
same insect, while above the wood is seen the perfect insect, a blue-
black beetle {Melandrya caraboides). The three stages are drawn
from nature and of the natural size, although (as in the case of
most wood feeders) the species is very variable in size, specimens
of the imago differing in length from seven-sixteenths to over
three-quarters of an inch. When first emerged from its pupal
form, this beetle is of a very light brown colour, and several hours

THE DENIZENS OF AN OLD CHERRY TREE. 5

elapse ere the rich, deep, normal shade of blue-black finally
appears. Its first appearance forms such a strange contrast to
that of the more matured insect, that we killed and set a newly-
emerged specimen for our collection. The perfect insects made
their appearance in our boxes at various intervals from April 27th
to May 8th, on which latter date we found several half-grown
larvae in the borings. We frequently observed the imago with its
head projecting from the mouth of the burrow made by the larvae,
into which it rapidly backed on our attempting to capture it.
These beetles are quick runners, and appear to emerge from the
burrows only after dark. The general hue of the larva is cream
colour, with pale-brown head. The jaws are darker and of a
horny nature, admirably adapted for eating its way into the wood,
and at the same time forming the burrows needed for its protec-
tion then and also in its future stages. Fig. i, PI. II. ^ shows
magnified dorsal view of the jaws of the larva.

The three pairs of legs, which are situated on the three seg-
ments next the head of the larva, enable it to move along its
burrow, and, combined with the sudden contraction of the seg-
ments, to perform the curious feat of repeatedly turning quite over
sideways, which feat we witnessed by placing several larvae on a
level surface. When put into a glass tube, they could in this
manner move along it, from which we infer that the larva not only
propels itself corkscrew fashion, but removes by the same means
the accumulating wood refuse of its labours. The larval stage
appears to continue for some considerable time, probably for more
than a year, but the pupal form seems to end in a few weeks. In
this stage it can move along the burrow by means of its angular
spine-studded segments and the two spine-tipped processes on the
lower side of the last segment. These burrows were more or less
filled with the wood particles evacuated by the larvae, whose sole
pabulum appears to be the rotten wood. From this strange food
Nature provides nutriment and builds up the insect through its
wonderful transformations.

We observed no insect parasites in the burrows of this beetle,
but on May 31st, on raising a block of the cherry wood containing
borings occupied by the young larvae of this beetle, we found a
female specimen of Pompilus spissus at rest on the wood, as if only

6 THE DENIZENS OF AN OLD CHERRY TREE.

lately emerged from the borings near it. This exceedingly active
and predacious insect belongs to a genus whose members chiefly
burrow in sand and generally prey on spiders. Mr. Edward
Saunders, who kindly identified the Aculeates bred from our
cherry stump, referring to this species, says : —

" Pompiliis spissus out of the stump is very interesting. I
wonder if it always inhabits such localities. I can find no actual
account of its habits, but always imagined that it nested in banks,
sands, etc., as its allies. It, however, lacks the comb of spines on
the front tarsi of its female, which are probably for digging pur-
poses (as most of the sand species possess them), so possibly it
may be a wood frequenter ; but it is quite unlike the other Po?7ipili
if it is. P. niger and P. minutiilus are also combless ; possibly
their habits are similar."

Of other beetles we found dead specimens of Calathus ciste-
loides and Sinodendron cylindricum, while the living imagines of the
following species were taken in April from the cherry bark when
cutting open the blocks, viz. : — Cis boleii, C. hispidiis, C. nitidus,
Anaspis frontalis, and A. fasciata.

The next inmates to claim our attention were the nymphs and
perfect forms of the solitary black wasps of the genus Pemph7'edo7i,
of which two species, P. hignbris (previously mentioned) and
P. Shuckardi, appeared in our boxes in the perfect state from
April 29th to the middle of May, P. lugubris being the most
numerous of any of the denizens of the stump. Its crooked and
stained burrows running in all directions, we sometimes met with
a long winding boring ending in several short branches, as in
Fig. 3, PI. I. In one of these short branch borings will be seen
the legless larva ; in another gallery will be found the nymph or
[Supal form of P. lugubris (this genus makes no cocoon), while the
imago, a female, is represented resting on the wood near. These
are all drawn natural size.

In our examination of the burrows of this species in April, the
larval stage was nearly over, as only two of the pale yellow, help-
less larvae were found, and these in a few days passed into the
nymph stage, which, compared to the larval life, is of short dura-
tion. The first imagines to appear were chiefly males, and out of
eighty specimens bred the proportion of males to females was ten

THE DENIZENS OF AN OLD CHERRY TREE. 7

to one. A male emerged with one pair of wings only and no
abdomen ; the fly, however, was very active and Uved for several
hours, and it was the only cripple observed.

The numerous borings of this industrious insect prove a subject
of great interest. They are not formed by the grub for the sake of
its food, as in the case of the beetle previously described ; but
the mother Pemphredon, with her cutting and toothed mandibles
(Fig. 2, PI. II.), gnaws away the wood, and removes it with great
dexterity with her legs, which are armed with spines that act like
rakes (Fig. 5, PI. II.), thus toiling on alone until the required
burrow is ready to receive the fruits of her labours, and form a
home for her progeny which she is destined never to see ! She
now sallies forth on a hunting expedition among the Aphides,
which are captured, stung, and paralysed, and let us hope ren-
dered insensible. In this condition the prey is brought home and
closely packed at the end of one of the burrows in sufficient
quantity to provide food for one of her family while in its larval
state. An egg is now laid in this larder,-'^ and over all sufficient of
the wood debris is packed to form a partition, against which ano-
ther larder is stocked and another egg deposited, the process being
repeated until her egg-laying powers are exhausted, and now, her
mission being accomplished, she dies as the summer fades ; while
in their separate retreats her tiny progeny emerge from their egg-
cradles to find themselves surrounded with food, which, owing to
the prescient action of the parent, is preserved from decay until
the larvae are full grown, and no longer require a carnivorous
pabulum. In the perfect state these Fossores feed on the nectar
of flowers and the sap of plants— a most interesting fact, for here
we have a herbivorous insect hunting and providing food for its
carnivorous young ! In the larval stage P. lugubris is subject to
the attack of the larvae of an Ichneumon fly {Perithous varius,
Fig. 14, PI. II.), of which three specimens emerged from these
borings ; and we can only infer that the parent Ichneumon gained
access to the burrow while its occupants were in the larval stage,
when it deposited its egg near or in its future prey.

* The remains of these larders consist chiefly of legs, heads, cornicles,
wings, and the extremities of antennae of aphides, some of which were sent to
Mr. H. C. A. Vine for identification, who kindly reported the genus to be
Siphonophora, and the species probably S. rosa and S. pisi.

8 TFIE DENIZENS OF AN OLD CHERRY TREE.

Another parasite of P. lugnbris^ nine specimens of which
appeared in our boxes between April 27th and June ist, was a
brilliant member of the Golden Wasp tribe (ChrysididcB)^ viz.,
Omalus auratus (Fig. 10, Plate II.), resembling, in splendour of
colours, the well-known ruby-tail fly {Chrysis igfiita), parasitic in
nests of mud-wasps {Odynerus), etc., but only about half the size
of that species. The ChrysididcE are, in every sense, Cuckoo flies,
for they make no nests, but lay their eggs in those of other Hymen-
optera, especially in those where provision has been stored for the
larvae. The little parasitic larva is hatched, and, it is said, feeds
in the larder with the larva of the original tenant, and when the
store of food is consumed it finishes up, not by ejecting its foster-
brother from the nest as the Cuckoo is said to do, but turns on its
companion, and sucks its juices. In the life-history of our Omalus
we had proof that this was the case, as, in each instance, we found
the pupal case of Omalus (Fig. 13, Plate II.) in the burrow of
Femphredon, and close to the remains of a larder, showing the
Aphides to have been eaten as well as the Pemphredon larva.

In speaking of a species of Cuckoo-fly {Hedychrum) allied to
Omalus, a French naturalist said he observed it enter the dwelling
of a Sand-bee in order to lay its egg. The intruder was discovered
by the bee, who at once proceeded to turn out its enemy by laying
hold of her with its mandibles. But the Hedychrum rolled herself
up like a ball, and was invulnerable. The bee carried her out,
gave her a good shaking, bit her wings off, and left her. She,
however, had her way for all that, and crawled back again into the
nest, and laid her egg. From the structure of the tarsi and ser-
rated claws of Omalus (Fig. 11, Plate II.), we imagine our Cuckoo
fly quite equal to the task, even without wings, of returning to the
borings of Pemphredon^ after having been summarily ejected by
the enraged fossore. From the burrows of Pet?iphredon appeared
several species of Diptera, and taking them in the order of Mr.
Verrall's British list, we have first three species of the family
Myceiophilidce, or " Fungus gnats " of the genus Sciaria, the
imagines of which emerged from April to June, about forty speci-
mens being observed. The larvae of these species appear to feed
on the mouldy contents of the larders of the fossores, especially
where the store food had not, from some cause, been eaten by the
larva for whom it was intended.

THE DENIZENS OF AN OLD CHERRY TREE. 9

On April 15th, in an untouched larder of Crabro (a genus of
fossores allied to Pemphredon), we found two larvae of Sciaria
feeding on mouldy imagines of Rhingia rostrata — the snout fly.
These small thread-like worms turned to curious horned pupae by
May 7th, and the resulting flies appeared in about three weeks,
showing this small dipteron to be parasitic on other and much
larger diptera, and possibly on Aphides, etc., in other fossorial
larders.

Continuing the list of Diptera from borings of Femphredon,
we find the family Chzronomidce represented by a species of Cera-
topogofi, whose pupae we found on June 2nd, and flies of both
sexes emerged a week later. We did not find the larva of this
tiny fly, but Mr. Theobald, in his British Flies, says of the larvae
of this genus, " that they inhabit manures, and others are found
under the bark of decaying trees," Some of the females of this
genus are blood suckers, and in early summer are a troublesome
pest to persons having tender skin, alighting on one's brow, neck,
or wrists, causing the most intense itching, and often severe inflam-
mation in the parts attacked. A gnat fly in comparison of size is
quite large to this minute, but terrible insect.

The next species of Diptera are two female specimens of
Trichomyia, bred about the end of May, following which is a
dipteron new to the British list, Brachycoma erratica, Mgn., of
the family Tachinidce, kindly identified, with the other Diptera of
our cherry stump, by Dr. Meade, of Bradford, who has fully
described this new species on page 110 in the May number of
The Etitomologisfs Monthly Magazine, 1894. During May, 1893,
we bred two specimens (male and female) of this species from
pupae found in the burrows of Fetnphredon — the male appearing
on May loth. Roughly speaking, this fly is much darker, but
similar in general appearance to a small specimen of the house fly
{Musca doinestica).

Of the large family AnthomyidcB our stump produced two
examples, viz., one female Hyetodesia errans on May 13th, and
several specimens of the well marked, striking species Hylemyia
/estiva, Zett. This last species is of rare occurrence in England.
It is described by Dr. Meade at page 222 Entomologisfs Monthly
Magazine, October, 1893, and on page 285 of the same magazine

10 THE DENIZENS OF AN OLD CHERRY TREE.

for December, 1893, he records the bred specimens above, the
pupae of which were found in April in burrows of Pemphi-edon
lugubrts, the flies, of both sexes, emerging during April and May.
In each case, the pupa of FI. /estiva was found close to the aphi-
dal remains of the Femphredon larder, and in two instances a
pupa was adjacent to a pupal case of Omalus^ showing the
parasitical dipteron connected in its economy with the parasitic
hymenopteron. From the same burrows of Pemphredon, during
April and May, appeared three specimens of Lonchcea vaginalis^
the last bred dipteron of our list.

We now come to the four remaining fossorial hymenoptera of
our cherry stump, all species of the extensive genus Crabro, whose
predaceous members provision their nests with Diptera. This
genus may always be determined by the constant neuration of the
wing (see Fig. 8, PL II.). The species have been tabulated by
Mr. Edward Saunders in The Transactio)is of the Entomological
Society^ 1880, pp. 280-281 ; also in his chief work on The
Hymenoptera Aciileata of the British Isles^ now being issued.
Fig. I, PI. I., shows a male of Crabro leucostofnus, a black shining
insect, and also four of the tough, sepia-coloured cocoons spun by
its larvae, from one of which the Crabro has emerged ; these are
all drawn natural size. The female is larger than the male, and,
from more than forty cocoons observed in our boxes, only seven per-
fect imagines appeared daring May, all of which were males. In the
burrow, each cocoon is in the position previously occupied by the
stores of the larder, some of the remains of which are usually seen
attached to one end of it, consisting chiefly of the harder portions
of the pretty green, metallic-looking dipteron, Microchrysa polita^
sometimes mixed with fragments of a brown and yellow species
of Melanostoma^ probably M. mellinum, a genus of the family
Syrphidcs. As this species was in the pupal stage when the cherry
wood was first examined in April, we did not find the larva. In
the larval stage this Crabro is subject to the attacks of the larva of
a small hymenopteron, Pteromalus apum, shown magnified (Fig. 9,
PI. II.). It is parasitic on many bees and wasps, and is a member
of the large family ChalcididcE, of which over one thousand British
species have been recorded. Each larva of Crabro leticostotmis
attacked by this little fly is destined to support several specimens

THE DENIZENS OF AN OLD CHERRY TREE. 11

of its larval enemy, which do not actually kill it until its cocoon is
spun, in which, after making a last meal of their host, they turn
to pupae. Those under observation appeared in the perfect state
in June, from six to nine flies emerging from one cocoon of their
host, while from one cocoon of a larger Crabro — C, cephalotes —
we took twenty-seven naked pupae of this parasite.

Another parasite of Crabro leucostotna is an Ichneumon,
Phygadeiion gravipes, of which two females emerged from the
burrows in June. The wings of this dark brown fly almost equal
in expanse those of its host, and its size indicates that the Crabro
cocoon is occupied by only one of its enemy.* Our remaining
species of Crab?o have the abdomen banded more or less with
black and yellow, and are easily mistaken by the non-entomologist
for small wasps, which they resemble, not only in shape and colour,
but in the possession of a powerful sting, so that care should be
exercised in the examination of living specimens. Like other
members of the genus they store their nests with living Diptera,
packed together in a state of torpor, and in their general economy
they appear to be similar to each other. The first of these
{Crabro vagus) is shown enlarged at Fig. 5, PL I., of which thirteen
specimens — chiefly males — appeared in June. It may be distin-
guished from the thirty British species of the genus by the entirely
black third segment of the abdomen. Its cocoon is the same
shape, but a trifle smaller, than that of Crabro chrysostomus (Fig. 4,
PI. I.), and its brown colour is a shade darker than the cocoon of
that species. So far as we have examined the larder remains of
this Crabro^ the stored Diptera appear to belong to the genera
Musca and Pollenia^ but it may bring home prey of other allied
genera, as in an untouched larder of a Crabro, which we inferred
was made by C vagus, but which did not produce a Crabro, owing
to the failure or non-deposition of the egg, we found two whole
male specimens of Musca corvina, and one whole female Stomoxys
calcitrans.

From the burrows of this Crabro a female specimen of Antho-
phora furcata (Fig. 6, PI. I.) emerged in June — the only bee met
with in the stump. Mr. Saunders, in speaking of this species,

* We are indebted to Mr. T. R. Billups for his kind identification of the
Parasitic Hymenoptera of our stump.

12 THE DENIZENS OF AN OLD CHERRY TREE.

says : — " How A. furcata came to exist as a single female in the
stump is curious. One would have thought that more examples
would have been in the same burrow ; possibly, however, these
died." After all the specimens of C. vagus had appeared, we
carefully examined the pieces of cherry wood in which it had
burrowed, but no other example of the bee in any stage could be
found. The gallery of the burrow from which the bee had
emerged had been much enlarged, and contained some wood
debris, of much finer particles than that in the other portions of the
Crabro burrow, from which we infer that the parent bee had
cleaned out, enlarged, and utilised for its nidus, a portion of the
Crabro home.

We now come to the most numerous, but one of the varied,
inhabitants of the stump, viz., Crabro chrysostof?ws {¥\g. 4, PI. I.),
where a female is drawn natural size with three of the vandyke-
brown cocoons in situ in the burrows, with their anal ends resting
on and partially, attached to the larder remains, which appear to
be chiefly specimens of the genus Platychirus. An untouched
larder in a portion of wood, consisting of several borings, with
cocoons of this Crabro, contained eight specimens of Platychirus
fulviventris. Of this interesting fossore we bred sixty-four males
and twelve females during May and June. The males, when
handled or touched, exhale a rich odour. The female can emit
the scent, but in a much less degree. This agreeable perfume we
have noticed when examining certain species of bees {Halicti),
but have not met with it in connection with other species of
Crabro. C chrysostomus is subject to the attacks of the parasitic
hymenopteron Pteromalus apum, mentioned previously in connec-
tion with C. leucostomus.

The last inmate of our stump to notice is Crabro cephalotes
(Fig. 6, Plate II.), the finest fossore of our series, and of which ten
males and four females made their exit from the cocoons. The
cocoon is shaped like C chrysostofuus, and of the same colour, but
rather larger. Fig. 4, PI. II., shows a pupa removed from its cocoon.
The burrows of this species contain the remains, and sometimes
whole specimens of the largest dipterous prey found in the stump.
In one nidus we found three whole specimens of Rhirigia rostrata^
and in another burrow were examples of Syrphus ribesii, insects

THE DENIZENS OF AN OLD CHERRY TREE. 13

fully half as large as their captor, and of strong flight. The
dexterity and power of the Crabi'o in securing and bringing home
such living prey is obvious, for, alone and unassisted, the burdened
insect unerringly flies home through the brilliant sunlight, and,
aided by a sense to us unknown^ deposits her burden in a chamber
where the light scarcely, or never, enters. This fine Crabro is also
subject to the attack of the little parasite Ptero7nahis apu77i^ and,
as noted elsewhere, we found in one of its cocoons twenty-seven
pupae of its enemy, while another cocoon examined contained
seventeen living specimens.

The marvellous industry displayed by the female fossores in
forming their varied burrows and galleries of each nidus is a sub-
ject of the greatest interest, and when we examine the organs and
limbs of these active creatures, our wonder is increased at their
beautiful adaptation to the functions performed. We cannot but
admire the suitability of such an instrument as the mandible of a
Crabro (Fig. 3, PI. II.) for reducing the wood into fragments
suitable for removal by the rakes and brushes of the leg (Fig. 7,
PI. II), and, did time and space permit, we should like to point
out many other interesting features in the economy of these
creatures. The appended list of insects found in this rotten stump
is not exhaustive, and its Fauna could have been much
extended with notices of the Crustaceans, Myriapods, and Arach-
noidea, met with in the mined wood ; while, to a student of Fungi,
several, and perhaps some uncommon forms, especially in connec-
tion with the fossorial stores, could have been observed. One
species, at least, appears to form part of the pabulum of the
larvse of the dipterous genus Sciara.

If by this brief and imperfect notice of the denizens of our
cherry stump we may arouse the interest of any reader to under-
take the investigation of some of the hidden marvels of the
insect world, our labour of love — performed under many difficul-
ties— vvill not have been in vain.

" There are deep thoughts of tranquil joy,
For those who thus their minds employ ;
And trace the wise design that lurks
In holy Nature's meanest works."

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Journal of Microscopy 3^ Ser.Vol. 5. Pi. 1.

CJ Wat kins, ad nat. de/.

F Phillips, Sc.

Journal of Microscopy 3^^ Ser.VoI 5 Pi. 2

C. J. ^atl^ms ad, nat. ofe/.

F. Phillips. Sc.

THE DENIZENS OF AN OLD CHERRY TREE. 17

Summary of Insects observed in the Cherry Stump.

Order.
Coleoptera

Groups or
Families.

••• 5

Genera.

5

Species.
8

No. of
Specimens.

52

Orthoptera

I

I

I

I

Hymenoptera

... 9

10

14

258

Lepidoptera

I

I

I

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Hemiptera

I

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2

12

DlPTERA ...

... 9

17

23

90

Total

... 26

35

49

414

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EXPLANATION OF PLATES I. and II.

Plate I.

Fior. 1. — Portion of rotten Cherry wood, showing nidus of Crabro
lencodomus (Linn.), with four cocoons, from one of which a
male imago has emerged. All drawn natural size.

,, 2. — Portion of rotten Cherry wood burrowed by the larva of
Melandrya caraboides (Linn.) shown in its burrow, with the
active pupa in an adjacent burrow. The imago is seen near
the wood at the top of this figure. All natural size.

,, 3. — Portion of rotten Cherry wood showing nidus of Pemphredon
Inguhris (Latr.) ; two of the galleries are occupied by the
larval and pupal forms respectively, and near the latter is a
female imago. All natural size.

4. — Portion of rotten Cherry wood showing borings of a female
Crabro chrysostomus (Lep.) containing three cocoons, with
their lower ends resting on the dipterous remains of the
larval larder. From the upper cocoon the female imago
shown has emerged. All natural size.

5. — Crabro vagus (Linn), female. Enlarged.

6. — Anthophora furcata (Panz.), female, enlarged. Bred from
boring of Crabro vagus.

Plate II.

Fig. 1. — Upper side of head of larva of Melandrya caraboides showing
toothed mandibles adapted for cutting and tearing wood
(2-inch objective).

,, 2. — Toothed mandible or jaw of female Pemphredon lugubris
(I-inch objective).

International Journal of Microscopy and Natural Science.

Third Series. Vol. V, c

18 THE DENIZENS OF AN OLD CHERRY TREE.

Fig. 3.— Toothed mandible or jaw of female Crahro cephalotes, Tanz.
(1-inch objective).

,, 4.— Pupa of Crahro cephcdotes, talcen from a cocoon in the Cherry
wood, enlarged.

^^ 5.— Front leg of female Pe\\-\phredo)i lugnbris, showing brushes
and rakes for clearing out the wood debris from the burrows
(2-inch objective).

5a. -Spur or calcar used for cleaning the Antenn?e, etc. (2-inch
objective).

6. — Crahro cephalotes, Panz., female, enlarged.

7, — Posterior leg of Crahro chrysostormis, Lep., showing spined
tibia adapted for clearing its burrows, etc. (2-inch objective).

8, — Anterior wing of Crahro, enlarged, typical of the genus.

9. — Fteromalus ajnim, Westw., Hymenopteron, parasitic on Crahro
leucostomus, Linn. ; enlarged.

10. — Omalus auratus, Dahlb , Hymenopteron, parasitic in borings
of Pemphredon Inguhris, Latr. (natural size).

11. — Portion of middle leg of Omalus auratvs. Dahlb., showing
spined tarsi and serrated claws (-^-inch objective).

12. — Anterior wing of Omalus anr ah is, Dahlb., enlarged.

13. — Cocoon of Omalus auratus, Dahlb., taken from boring of
Fempliredon luguhris, Latr., in the rotten Cherry wood
(natural size).

14. — Parasitic Ichneumon, Perithous variiis, Gr. , female, bred from
borings of Pemphredon (natural size).

Drawn by Charles J. Watkins.

jj

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Concerning famines in India, which were formerly often ter-
rible, Mr. C. E. D. Black, in his third decennial report of progress,
does not deny the existence of " habitually starving millions,"
but maintains that, taking the country as a wdiole, it can always
furnish food enough for all its inhabitants. The difficulty has
hitherto been in moving the surplus of one or other locality to
the spots where deficiency exists. This has now been mainly
overcome, and the days when grain was selling at famine prices in
one district and rotting on the ground in another are gone.
Registered meteorological observations indicate that, as a rule,
two-thirds of India are affected each year, either favourably or
prejudicially, differently from the other third. 'I'here is no record
of a universal failure of crops, any more than of a general harvest
above the average.

[ 19 ]

cTbe ^Development of tbe (Berm C^beor?.

By H. Langley Browne, F.R.C.S.E.*

AS this is one of the occasions upon which custom decrees the
breaking of the rule that silence is golden, and having
nothing in the way of original research or discovery to
bring before you, I think it may be not uninteresting if I draw
your attention for a few moments to the *' Modern Development
of the Germ Theory of Disease."

The theory itself is by no means a new one, though the proofs
of it have only been forthcoming recently and even yet are not
complete. Linnaeus published an article in 1730. attributing
smallpox, measles, plague, syphilis, dysentery, and whooping-cough
to the agency of minute animals. Ehrenberg in 1828 found
numerous organisms in water and dust, and designated them
" infusion animals," and in remarking upon the highly organised
structure, astonishing minuteness, and fecundity of these animals,
argued that they might cause many of the diseases affecting man ;
and Schwann in 1837 declared that the atmosphere was laden
with germs of fermentation and putrefaction.

In 1839 Sir Henry Holland published in his Medical Notes
and Reflections an article on the " Hypothesis of Animalcule Life
as a Cause of Disease " ; an article so clear and logical that I
propose to review it at some length. He thought that certain
diseases, and particularly some of the epidemic and contagious
ones, were derived from some species of animalcule life, existing
in the atmosphere under certain circumstances, and capable, by
application to the lining membrane, of acting as a virus on the
human body. He maintained that there are conditions of animal
life in the atmosphere as minute, as numerous, as variously
diffused as those visible by the aid of the microscope in water,
and that we are carried so far by our actual knowledge of these
minute forms of existence, and by such uniform gradations of
change, that we must not suppose the series to stop because we
can no longer draw evidence from our own senses. This would

* President's Address, read at the Annual Meeting of the Birmingham and
Midland Branch of the British Medical Association June 14, 1894.

20 DEVELOPMENT OF THE GERM THEORY.

imply a sudden breach of continuity such as we find in no other
part of the scale of animal life, and be contrary to the opinion of
Locke, " that in all the corporeal world we see no chasms or gaps."

Admitting, however, that even if we never reach actual proofs
of the existence of these minute forms of life, be they insect or of
other kind, he argues that the probability of their existence is
little lessened by the failure, considering the obstacles which have
to be surmounted. And, if existing, we may presume that they
have many points of affinity with well-known insect genera, such
as sudden generation at irregular and often distant periods under
certain conditions of season or locality, and the diffusion of the
swarms so generated over wide tracts of country often following
particular lines of movement. Whatever is true or peculiar to the
habits of insects, or the forms of animalcule life, obvious to our
senses, is likely to be equally applicable to those whose minuteness
removes them further from our observation. Their generation
may be presumed to be even more dependent on casualties of
season or place, their movements determined by causes of which
we .are less cognizant, and their power of morbidly affecting the
body, to be in some proportion to their multitude and minuteness.

Claiming that these considerations are of great interest to the
general theory of disease, he says they have close reference to
contagious exanthemata in particular ; and though not sanctioned
by any direct proofs in relation to these diseases, yet fully justify
the prosecution of the research through every possible channel
and render plausible, at least, the arguments of those who have
ventured to support the opinion that they depend upon the action
and phenomena of parasitic life.

Having regarded the question as to whether the epidemic ten-
dency of carbuncular boils has not depended on causes from
without, giving hydrophobia and glanders as instances of disease
conveyed from animals to man ; noting that epidemic influenzas
are in no way produced by atmospheric states or changes, he then
takes up the subject of cholera, and proceeds in the most masterly
manner to elucidate his theory by the remarkable phenomena
shown in this disease.

After tracing the history of its diffusion for twenty years under
every climate, in every place, the disease being always absolutely

DEVELOPMENT OF THE GERM THEORY. 21

identical, he states that we have not the smallest reason, from
knowledge or analogy, to assume that any gaseous, mineral, or
vegetable matter diffused from the atmosphere or exhaling from
the earth, could create a disorder or spread it in a manner so
remarkable over the globe ; and equally inapplicable, for the same
reasons, is every theory founded on the temperature, habits, food,
or other conditions of particular communities.

Further, he says, it must be kept in mind that we have to deal
here with immigrating malaria, a wandering cause of disease,
capable not merely of being diffused through the atmo-
sphere and conveyed along vast tracts or lines over the globe,
affecting diiferent places with a varying intensity which no known
condition of earth, atmosphere, or human habits can explain,
but also possessing the power of reproducing itself so as to
spread the disorder by fresh creation of the virus which first
evolved it. This faculty of reproduction stands foremost among
the conditions essential to a right theory of cholera; all our
reasoning stops short unless under recognition of the fact so
stated. Without it there would seem a physical impossibility in
explaining the phenomena of the disease, and particularly its dis-
tribution and succession in different places and seasons. A
thorough study of these singular details of its history, keeping
this principle constantly in view, will not only confirm and illus-
irate the latter, but will lead us to organic life as the only conceiv.
able source and subject of such reproduction. It is against all the
analogy of nature to suppose this power to belong to inorganic
matter. Either animal or vegetable life, in their simpler forms,
must furnish the material cause we seek for, since to them alone
can belong the faculty of renewing indefinitely the active cause of
the disease.

These enlightened views were held by Sir Henry Holland, and
give the fullest early account of the germ theory of disease which
I am able to bring before you. They form a brilliant example of
the scientific use of the imagination, and although again very
forcibly brought forward by Henle in 1840, it was a theory hardly
accepted by the profession, and very many years elapsed before
any proofs were forthcoming in support of it.

Indeed, if we pass over a period of thirty-six yeaes and take

22 DEVELOPMENT OF THE GERM THEORY.

von Ziemssen's Cyclopaedia of Medicine^ published in 1875, ^^ ^^^
Liebermeister, in his introduction to Infections Diseases^ recording
nearly the same views without being able to bring forward much
more actual proof of them. He refers to the hypotheses produced
up to our time by both the learned and unlearned, most of them
not very poetic, but about as vague as the descriptions of the old
poets who wrote of the "death-dealing shafts of Apollo;^' or as
the views advanced in a well-known novel, where cholera is asso-
ciated with the footsteps of the wandering Jew. He mentions that
in all great epidemics, since the time of the Athenian plague,
there has been a revival of the popular notion that the wells were
poisoned, and says that this idea had certainly the advantage over
most of the hypotheses which were clothed in scientific guise,
inasmuch as it supposed a real cause.

Referring to the theory of contagium vivum, and alluding to
its antiquity, he shows how, in later times, it had been maintained
with decided ill luck, 'i'he statements of the first observers who
believed that they had found the organisms that were at the basis
of all epidemic diseases, were soon recognised as too hasty or
overdrawn, the animalculae of smallpox, of cholera, and of choler-
aic Tungi, proved to be quite common infusorial organisms, such
as can be found in all decomposing substances. About the middle
of the present century, the judgment of condemnation of this
theory was almost unanimous ; it has been regarded pretty gene-
rally as an unreal, unscientific play of fancy. Among the medical
authorities^ Henle was probably the last who elaborated the theory
of a contagium vivum. This he did in 1853, with as much
modesty as thoroughness, though even as early as 1840 he had
maintained it with convincing logic.

Liebermeister gives very fully his own reasons for maintaining
the correctness of the theory : — New investigations on the appear-
ance, mode of propagation, and significance of low organisms \
the fact that the poisons of infectious diseases can reproduce
themselves to an unlimited extent; that with a minimum quantity
of vaccine virus we can vaccinate a child, from this child ten, and
so on ad iiifinitwn ; as with vaccine virus so with variola, measles^
scarlet fever, typhus, etc., the poison can be multiplied to an
endless extent.

DEVELOPMENT OF THE GERM THEORY. 23

Among chemical actions, it is chiefly the processes of fermen-
tation and decomposition which, by their capacity for extension by
means of the smallest possible quantity of matter, show the most
striking analogy to contagious diseases ; and we know now that
these ferment processes are all associated with the multiplication
of low organisms, so that the theory of fermentation becomes vir-
tually identical with the theory of a contagium vivum,

Liebermeister insists on the fact that contagious diseases never
originate spontaneously, but are dependent on a transmission, a
continued propagation, of a disease-poison. He notes also that
the contagious diseases of the silkworm have been proved to be
parasitic, and the history of the development of the parasite has
been followed pretty thoroughly; but he omits altogether any
reference to Pasteur, whose work this was, and in his search for
proofs for his theory is apparently ignorant of the work of Lister
in this country.

Immense advances have been made since 1875 ^^ ^^^ discovery
of the special micro-organisms of the diseases then recognised as
infectious, and many additions have been made to the list of these
latter. The denizens of this invisible world which have so long
escaped observation are now being dragged into the light of day
and subjected to the closest investigation. The study of micro-
organisms has become a necessary part of medical education, and
attempts at classification have been made, and many terrible and
prodigiously long names coined to express withal the groupings,
functions, and forms of these little beings.

To enable students to pursue these studies with greater ease,
the German Government spent ^12,000 in bringing the lens to a
higher state of perfection, with the result of obtaining one abso-
lutely achromatic.

For the first year they kept the secret of this wonderful lens,
and then gave it to the world. With such a lens and by staining
the objects under the cover-glass, it is easy now to detect the
presence and study the ways and habits of these micro-organisms.*
It is undoubtedly to Pasteur that the credit is due for the early
discoveries in bacteriology. He proved that not only did water
teem with life — this had long been known — but that the air around

* Tke Reahn of the Microbe (Priestley).

24 DEVELOPMENT OF THE GERM THEORY.

US was also filled with germs of every kind. Without laying claim
to being the first discoverer of germs in connection with disease,
he was the first to recognise the vast importance of these minute
organisms in the economy of nature. It was while working at
molecular physics that the germ theory took root in his mind, and
caused him to pursue the studies on fermentation, which even-
tually led to the investigation of " ferment " diseases affecting
human beings and cattle. He divided micro-organisms into two
great classes, : the aerobic and the anaerobic — those which require
free oxygen for their existence and those which are killed by it.
The former begin their work on the surface of things, their
mission being to clear the earth, by a process of slow combustion,
of all that is dead ; the latter, working simultaneously, spring into
activity underneath the surface of putrescide matter and die on
exposure to the free oxygen of the air, and are in their turn swept
away by those on the surface.''" Thus the two great classes of
minute living organisms co-operate towards the fulfilment of a
common end, the one beginning work which the other takes up
and completes. They also attack our plants as parasites, bring-
ing degeneration and death to their hosts, and at times cause the
severest diseases in the lower and higher animals, and threaten
even man himself with fatal epidemics. On the other hand, but
for their united efforts, we should cease to live, for the earth would
be littered with fallen debris and organic matter of every kind, all
of which It is their duty to transmute into the very elements which
are essential to life.

Pasteur had discovered that diseases affecting beer or wine
were due to microbes which reached the vats through the air, and
that no disease appeared if the air were filtered or sterilised. He
had established the vitality of all ferments, harmless or noxious,
and had proved that the spores were carried to their respective
breeding-grounds through the pollen of flowers or dust of the air.
This was the first true indication of how disease travelled, and
that it was intangible, invisible, and belonged to the lowest forms
of vegetable life. He then turned his attention to the disease
affecting silkworms, which was then threatening to extinguish a
vast industry, and by a series of the most careful experiments

* Realm of the Microbe (Priestley).

DEVELOPMENT OF THE GERM THEORY. 25

proved that this disease was of two kinds, both depending upon
micro-organisms. In his investigations, he came upon some very
interesting points as to the mode of infection, which threw much
hght upon all diseases, whether affecting animals or human beings.
First, that in the eggs laid by a diseased moth the germs could
maintain their vitality when thus enveloped and protected from
the outer air, and so could transmit the disease by heredity.
Secondly, that climbing over each other, after having crawled over
infected leaves, they would inflict occasional pricks with the sharp
hooks on their legs, thus causing direct inoculation of the disease;
and thirdly, that in a perfectly healthy state the digestive functions
of silkworms were so active that the germs of the disease were
carried away quickly or destroyed in the same manner as the
leaves in the process of digestion ; but that if by any cause the
digestion of the worms be impaired, the germs were able to mul-
tiply rapidly, and the worm was doomed to perish.

By destroying the infected eggs and the worms suffering from
hereditary weak digestion, and by improving the hygienic condi-
tions of the environment, he was able completely to stanip out the
disease, and to restore the silkworm industry to its former
prosperity.

Lemaire, proceeding upon Pasteur's lines, after proving that
the presence of carbolic acid was inimical to the life of higher
plants and animals, carried his researches further, and found that
the lower organisms were similarly affected by the same material;
and that the addition of a small quantity of carbolic acid to fluids
in which putrefaction and fermentation would ordinarily take
place prevented the incidence of these processes ; and reasoning
that disease processes, such as pus formation, w^ere the result of
fermentations or decompositions brought about by the action of
germs, he concluded that they might be prevented by similar
treatment, and he actually applied this antiseptic treatment suc-
cessfully on the wounds of the human subject and of the dog.

Lister independently came to the same conclusions ; but owing
to the difficulty of killing the germs after they had once made
their way into the tissues, he recognised the absolute necessity of
preventing such organisms gaining access to the wounds at all, and
founded his well-known antiseptic treatment for the attainment of
this end.

26 DEVELOPMENT OF THE GERM THEORY.

Koch, Klein, Klels, Nicolaier, Pasteur, and many other noted
men have been at work upon this branch of pathology, and spe-
cific microbes have been recognised as the cause of disease in
anthrax, relapsing fever, actino-mycosis, thrush, ophthalmia, enteric
fever, cholera, diphtheria, gonorrhoea, glanders, tetanus, tubercu-
losis, influenza, cerebro spinal fever, dysentery, diarrhcea, erysipe-
las, foot and mouth disease, hospital gangrene, hydrophobia,
malarial fever, measles, mumps, scarlet fever, yellow fever, pneu-
monia, phagedaena, puerperal fever, and pyaemia. In chickenpox,
cowpox, smallpox, plague syphilis, typhus, and whooping-cough,
no true specific microbe has yet been discovered, but there is no
reason to doubt that they exist. Probably, Koch's researches and
discovery of the cause of tuberculosis in 1882 and of cholera in
1884 are the most important. In fact, so much importance has
been deservedly attached to Koch's work, that when a few years
ago he propounded a method of treating tuberculosis by the sub-
cutaneous injection of a preparation composed of the toxines pro-
duced by the action of his bacillus, his proposition was received
with universal enthusiasm. Unfortunately, this treatment has not
fulfilled its promise ; but the attention thus drawn to tuberculosis
has added immensely to our knowledge of the disease.

Owing to the development of bacteriology, surgeons especially
have had to extend and enlarge their ideas of infection, and make
many alterations in their pathology. Every true inflammation,
various forms of necrosis and suppuration, the abscesses, the
phlegmonous and purulent inflammations, boils, carbuncles, osteo-
myelitis, suppurative arthritis, endo-cranial suppuration, and brain
abscess ; empyema, suppurative pericarditis and peritonitis, septi-
caemia, pyemia, erysipelas, tetanus, hydrophobia, and the multiple
forms of tuberculosis, anthrax, and glanders, are now known to be
infection-diseases due to the presence of microbes. These
microbes are in the air, the water, and the soil, in our immediate
surroundings, in our dwellings, and in our food ; present as our
constant companions and at times as our dangerous foes.

The entrance of these germs is most easily eff'ected when
there is any abrasion, and thus it was in wounds that the septic
influence of these microbes was most apparent, and it was to their
exclusion from wounds that attention was first turned.

DEVELOPMENT OF THE GERM THEORY. 27

Lister, with a combination of experimental resource, patience,
and brilliancy, almost unparallelled in the history of surgical
science, step by step, built up a theory and practice of antiseptic
surgery — a theory and practice which rapidly revolutionised
the treatment of wounds and the routine of ward management.
He introduced a system which has affected the practice, not only
of those who believe in its accuracy, but of those who cannot
accept all the details, yet have nevertheless adopted its principles.
He proved conclusively, and his proofs have been confirmed by
many others, that ordinary cleanliness in the dressing of wounds,
either made or treated by the surgeon, was not sufficient ; but that
the use of some kind of antiseptic was absolutely necessary to
avoid the risk of septic infection. Surgery and its subjects owe to
Lister a debt which can never be repaid.

These germs may also find an entrance through the skin and
hair follicles, and give rise to localised centres of infection, such
as boils, carbuncles, and different forms of cellulites, or they may
be swallowed or inhaled, be taken up and circulated by the leuco-
cytes, and deposited at any seat of injury or irritation, and as
these germs are constantly present under ordinary conditions of
life, their effects would certainly be much more constantly in evi-
dence were there not some natural safeguarding influence. It has
long been known that certain cells in the living body are capable
of removing absorbable aseptic substances, such as cat-gut liga-
tures, etc. Metschnikoff introduced the term phagocytosis to
designate the process by which the leucocytes and other cells
destroy or digest pathogenic micro-organisms, and the cells which
perform these functions he calls phagocytes. The leucocytes are
the ordinary police intrusted with the duty of taking up unautho-
rised intruders, but in moving them on sometimes they let them
escape. But the other cells — the mucous corpuscles, connective
tissue, cells, endothelia of blood-vessels, and lymphatic vessels,
alveolar epithelium of the lungs and the cells of the spleen, bones,
marrow, and lymphatic glands — may all be enrolled as special
constables to repel an invasion in force. When the struggle
between a microbe and a phagocyte turns out in favour of the
latter, the microbe does not multiply in the protoplasm, or ceases
to do so before the protoplasm is destroyed, and as the microbe

28 DEVELOPMENT OF THE GERM THEORY.

cannot leave without dissolution of the cell, it remains within its
narrow confines, and is destroyed either by some as yet unknown
chemical substance or dies from starvation. In either event the
vitality of the cell is not impaired, and the microbe disintegrates
or disappears. If the conditions for the growth and development
of the microbe in the protoplasm of the cell are more favourable,
intra-celiular multiplication of the microbe takes place ; the pto-
maines which are eliminated produce coagulation-necrosis in the
protoplasm ; the cell disintegrates ; and the intercellular culture is
liberated in an active condition.

In cases of unsuccessful warfare of the phagocytes against
invading micro-organisms, the mechanical obstruction composed
of emigration corpuscles and embryonic cells is broken down ;
and the rapid increase of micro-organisms at the seat of inflam-
mation gives rise to extensive local and often general infection.
From a practical standpoint, it can be said that all therapeutic
measures which influence favourably the process of phagocytosis
in the broadest meaning of this word are calculated to exert a
potent influence in arresting or limiting the infective processes.
For example, the application of counter irritants around an
inflamed centre would cause an active immigration of leucocytes,
and it is probably upon this that their well-known usefulness
depends.

In addition to this vis inedicati-ix fiaturce just pointed out, we
can do a very great deal for our own protection, and the old
adage that prevention is better than cure points out to us the lines
upon which we should proceed. It is in the field of preventive
medicine we have done most and have still much to do. The
personal care of the health ; the notification and isolation of
disease ; the disinfection of disease areas ; the preventive and
curative inoculations ; the inspection of our food supplies ; the
drainage and ventilation of our soils and houses ; the establish-
ment of laboratories in connection with our PubHc Health Depart-
ments for studying the history of infectious diseases in man and
animals ; in fact, the improvement of every condition of life leaves
a large field still open for our work.

The author of Civilisatiofi : Its Cause and Cure, says : — " If
the extent of the national sickness is such that we require 23,000

DEVELOPMENT OF THE GERM THEORY, 29

medical men to attend to us, it must surely be rather serious !
And they do not cure us." Well, if all these medical men will
believe in the germ theory of infection, that these germs do not
exist only in the brains of those who discover them, and if they
will thoroughly act up to such a belief, the national condition may
be greatly changed for the better — if not by doing away with all
the ills that flesh is heir to, at least by considerably diminishing
the number of those which are due to infection.

Notes and Reflections, by Sir Henry Holland ; Von Ziemssen's
Cyciopcedia, Vol. I. ; Bacteria afid their Products (Wood head) ;
The Realm of the Microbe (Priestley) : Fid?lic Health Problems
(Sykes); Surgical Principles (Lenn.) ; Micro-Organisms and
Disease (Flugge).

ZTecbnoloQ^ of tbe Diatomace^.

By M. J. Tempere.*
Chapter II. (conti?iued).

SPECIAL TREATMENTS.- SOUNDINGS.

SOUNDINGS are certainly the materials that offer to Diatom-
ists the greatest interest and at the same time all the chances
of disappointment. 1 say the greatest interest, because
we have there to deal with species actually living in our seas and
lakes ; all those who have attempted the cleaning and examina-
tion of Soundings will realise what I mean when I say there is
much that tends towards disappointment. I advise the beginner,
therefore, to lay in a stock of patience, and not to be discouraged
if the result of his attempts should be absolutely nothing, for
unless the materials on which he is about to operate have been
warranted to contain Diatoms, it will very likely prove that seven
or eight times out of ten there is nothing to find, and that his
time has been lost.

A rapid, off-hand examination of a sounding, especially if you
have only a small quantity to operate on, may very often show no
trace of Diatoms, though the material does really contain them,

* Translated from Le Diatomiste.

30 TECHNOLOGY OF THE D1AT0MACE.E.

for it is only after a series of manipulations that it is possible to
ascertain its richness or sterility as regards organisms of this kind.
I have many times had at my disposal one or two killogrammes of
marine deposit, in which repeated examinations under the micro-
scope showed nothing, but which, after having been subjected to
the^ needful manipulations, have given excellent results, not as
regards quantity, but from the specially interesting species that
were extracted.

Soundings are of many kinds and are obtained by different
methods. Formerly, it was and even sometimes now is, the prac-
tice to cover the lower side of a leaden weight (held by a slender
cord) with fat or hard soap, to the surface of which a small quan-
tity of the mud which forms the sea-bottom adheres.

Nothing can be more detestable to thediatomist than this kind
of material — in the first place, because he has to get rid of the
grease or soap employed ; and then because it is only possible by
this means to place at his disposal so small a quantity, and that it
cannot give an idea of the richness of the bottom whence it comes.

The fatty or resinous matters are removed by washing with
ether or benzine, and the soap by hot water. The sediment then
having been well dried, is treated with a series of acids and the
usual reagents.

In general, it is by means of special sounding-leads or drags,
or by means of nets, that this material is obtained in any quantity
and appears as argillaceous or sandy mud, more or less calcareous,
mixed up with fine debris of all sorts belonging to the three king-
doms, brought up by the lead or the drag.

All the differing materials require to be treated according to
their nature. 1 will therefore pass them in review, and indicate
the special treatment that each requires.

Treatment of argillaceous or earthy Muds and the extraction
of the contained Diatoms by '' floatage."— The argillaceous or
earthy muds, produced of marine soundings, are rarely very rich
in Diatoms ; often, as I have said, they contain none at all. You
may assure yourself of their presence and even withdraw the
greater part by the method oi floatage. For this purpose the
material must be perfectly dried, either by exposure to sunshine or

TECHNOLOGY OF THE DIATOMACE^. 31

in a slow oven, taking great care to avoid all contact with any
greasy matters."

When perfectly dry, the mud is broken into fragments, if it has
agglomerated in drying, and thrown into a vessel sufficiently large
and filled two-thirds of water (a tumbler-glass or a celery glass,
for instance). The whole is rapidly mixed, and then after one or
two minutes of repose carefully remove, by means of a spoon, a
kind of scum that will be seen to float on the surface. It is spe-
cially on the edges and against the sides of the vessel that the
scum is most abundant, and one may use with advantage a large
soft brush to remove it, pressing lightly all round the vessel. This
operation, if the mass is considerable, may be repeated twice or
even three times.

If the mud contains Diatoms, an examination under the
microscope will show a great abundance of frustules, filled with
air, which has caused them to float on the surface of the water.
If nothing is seen after a treatment of this kind, it is a proof that
the sounding is sterile, and may then be rejected. (For fossil
earths of the same nature the case is different, and the absence of
Diatoms in the floatage is not to be taken as a proof of sterility.)

The collected scum, placed in a porcelain capsule with a little
water, is brought to the boiling point for a few minutes to drive
the air out of the Diatoms, which on cooling will collect at the
bottom of the vessel and may then be treated with acids.

Extraction of the Diatoms remaining in the aforesaid floated
materials.— Many valves and frustules of Diatoms may be
extracted from the mud already floated by the following means : —

I St. — Tamise the whole with ordinary muslin of sufficient
solidity, and having meshes of a millimetre, which will allow all
the Diatoms to pass through, retaining only the more bulky
rubbish — shells, stones, etc. — which may be thrown away.

2nd. — The deposit thus obtained may be again tamised,
employing the No. i or 2 filter, according to the size of the
Diatoms contained. When the water passes through clear, you
must treat the part that remains on the filter with a series of acids
and re-agents till it is perfectly cleaned.

* Mr. W. H. Shruhole has made known this process, which he has
employed, for removing the Diatoms contained in the mud of the Thames, in
The Leisure Hour, 1 891, p. 387.

32 TECHNOLOGY OF THE DIATOMACE^.

3rd. — The sediment resulting from this second operation
should be treated in the same manner, using filter No. 3, which
will usually, in the case of marine diatoms, give a final result ;
that is to say, that all the organisms contained in the soundings
will be found in the filter.

The filter No. 4 need only be used if the mud contains very
minute species, and sufficiently interesting to call for its use, for
the work with this number is very slow and takes up a great deal
of time and patience, when a large quantity is to be operated upon.

Extraction of Diatoms contained in the larger debris of
various kinds collected by the drags and nets. — The materials,
more or less bulky, collected by the drags and nets, ought to be
carefully tested ; whether fresh or dry matters little. You should
put apart the Algae, the Sponges (these ought to be themselves
divided into classes, as I have already shown),* the debris of
fishes and echinoderms, and, lastly, the stones composed of calca-
reous concretions, tubes of annelids, fragments of rock, etc.

The preliminary washing of each of these different kinds
should be done separately, mixing ultimately those that appear
alike.

I have indicated in previous numbers the course to be followed

for the cleaning of Diatoms derived from Algae and from Sponges.

The stones, if they are too large, must be broken up and treated

as shells, etc.

(To be continued.)

M. Treby's studies of the planet Jupiter for the last thirteen
or fourteen years have satisfied him that the conditions existing
there are more stable than astronomers have of late years been
supposing. Even if the phenomena of the spots and bands are
atmospheric, their permanency and regularity point to some fixed
cause on the real surface of the planet controlling them. Besides
the " red spot/' which has now attracted attention for many years,
he finds permanent spots, even on the equatorial zone, having a
movement of rotation corresponding with that of this object. The
supposition may be legitimately drawn from this fact that this period
of rotation agrees with that of the planet itself

* See this Journal, 111., Vol, iv. (1894), p. 307.

[ 33 ]

pre^actou6 & iparaeitic lenemiea of apbibea

(JncluMnc} a StuD^ ot Ib^per^parasltes).

By H. C. a. Vine. Plates III. & IV.
J^ar^ II. — continued.

IN studying the anatomy of the Aphidivorous Syrphidse,
perhaps no point will more strongly fix the attention, even
of a very casual observer, than the vast difference in the
structure of the alimentary systems of the larva and the imago.

The exclusively animal food of the larva is obtained and
assimilated by organs whose special adaptation for the purpose is
remarkable, even in a section of the animal kingdom teeming
with remarkable and extraordinary structures. In the imago the
wholly vegetable diet is taken into the system by the most com-
plex and delicate suctorial organ known, and applied to the
maintenance, and more especially to the reproduction, of life by
equally elaborate alimentary and excretory organs, which present
many points of resemblance to those of graminivorous animals.

I am quite aware that similar changes of food and structure
prevail throughout the diptera, and in a less degree among many
other insects ; but I do not know of any group (unless among the
Neuroptera) in which the contrast is so complete, for the larvae of
Aphidivorous Syrphidae are not only carnivorous, but they hunt
and kill the creatures they require for food.

The Mouth Parts of the Larva.

In the Aphidivorous Syrphidae the mandibles are represented
by a pair of strong hooks attached to a chitinous foundation,
situated on either side of the ventral folds of the epidermis, behind
the opening of the mouth, and immediately behind and beneath
the frontal papillae. When the larva is in a state of repose, they
are hidden within the body, and appear when the evagination of
the mouth parts has proceeded sufficiently for the papillae to
become visible (PI. III., Fig. 5,^,^).

These hooks (PI. III., Fig. 7) are broad at base, short, hooked
slightly, and sharply pointed. They are unarticulated in any way,
and appear to derive their power of movement from the flexibility
of the derma, of which they are a process. A muscular band

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. d

34 PREDACIOUS AND PARASITIC

may sometimes be observed behind them ; but I am inclined to
think that it has no special function as to the hooks, but probably
assists in the general movements of the skin.

As the larva extends its head by continuing its evagination,
folds become visible representing another segment, almost entirely
dorsal, which bears on either side a fleshy protuberance carrying
two papillae, which are no doubt organs of special sense. These
are shown on PI. III. at Figs. 5 and 9, and will be further des-
cribed. Midway between these protuberances an implication of
the epidermis, parallel to the length of the larvae (for at this stage
of extension the dorsal surface is considerably in advance of the
ventral) forms the upper margin of the mouth, from which the
points of the piercing and sucking organ may generally be seen
protruding. They are shown at e in Fig. 9.

This latter organ has been figured by Reaumur, De Geer, and
other writers, but scarcely in sufficient detail for the figures to be
useful. It may and probably does represent the first two segments
of the head.

In general shape it may be described as resembling the bill of
a flat-billed bird, such as a duck. It consists, as to its upper part
of an arched, chitinous framework, with posterior extensions form-
ing two elongated blades or plates {d, d, Fig. 2). Forwards, a
long spear-headed or lancet-shaped process extends to form the
upper half of the " bill," having its extremity slightly rounded and
with a central groove, somewhat like a carpenter's gouge. This is
opposed on the underside by a plate of somewhat similar shape,
but deeply indented on either side, and furnished at its extremity,
which is pointed obliquely, with a thin, hard edge of great trans-
parency (PI. III., Fig. 6). This half of the organ is not articu-
lated in any way, but its base is lost in the mass of muscles {e, e^
Fig. 4), which, surrounding and inserted into the flat plates before
mentioned, give appropriate movement to the two halves of the
" bill."

These latter are continuous with, and merge into, the upper
and lower surfaces respectively of the pharynx, which, protected by
the chitinous plates and strengthened by a series of slight rings of
this material (occasionally the rings seem to become plates), passes
through the muscle, as is indicated at/,/. Fig. 4, and continues

ENEMIES OF APHIDES. 35

as the oesophagus (Fig. i, <?, PI. III.). The transverse muscles
shown in Fig. 4, PI. III., are sheathed by longitudinal bands, as
shown at ^, Fig. i. Together they control the opposition of the
upper and lower blades of the piercing organ, and by causing
rhythmic contractions at the base of the pharynx cause it to act as
a powerful suctorial organ. On either side of the head are three
long muscular bands, arising from the epidermis and inserted
into the framework of the piercing organ, as shown at d^ d, Fig. i,
PI. III., which control the forward and retractile movements with
great completeness.

The Digestive Organs of the Larva.

An outline of the alimentary system has been already given in
the last section in explanation of the first figure of PI. XV. (Vol. 4).

The most notable features are the extensive salivary glands
and the great capacity of the stomach. The anterior portions of the
former are shown at n, PI. III., Fig. i. Each consists of a blind tube
of delicate, unorganised membrane, lined with large, nucleated, epi-
thelial cells. The tube is greatly enlarged at its remote or blind
end, and after doubling upon itself for half the length of the larva is
lost at its narrow end among the muscles surrounding the pharynx.
The outer surface is smooth, and the nature of the fluid secreted
differs from that secreted by similar organs in the imago, inasmuch
as it does not coagulate in water. The secretion of the larva is
probably non-albuminous, or at most only very slightly so.

The structure of the stomach presents no peculiarities suffi-
cient to occupy our attention here. Under an amplification of
1,000 diameters, it presents no appearance of organisation beyond
faint traces of striation here and there, showing the existence of a
muscular coat.

One other point may be noted, which may possibly be of value
in the future classification of the larvae — that is, the colour of the
hepatic vessels. Thus, in certain larvae, and especially in the
larva of Syr. limiger, these vessels are yellow to brown. In another
group of larvae, distinguished by a clear pink stripe down the
centre of the back, they are green, while in some very transparent
larvae, which I have not succeeded in rearing, they are of a deep
crimson.

36 PREDACIOUS AND PARASITIC

The Tracheal System.

The general plan of the apparatus fulfilling the important
functions of respiration has been exhibited at Fig. 2 of PI. XV.
(Vol. 4).

Two large and exceedingly delicate tubes (there marked b^ b,
and in PI. III., Fig. i, marked h, g), containing in their walls the
usual spiral elastic thread, traverse the whole length of the larva,
one on either side. Towards the extremity of the head, at a
point well invaginated when the larva is in a state of rest, these
tubes protrude, carrying with them a conical extension of the epi-
dermis, and presenting in some aspects (and especially when the
insect is in the act of extending itself) the appearance of a pair of
palpi. They terminate each in a narrowed, rounded point, fur-
nished with chitinous slits for the admission of air, the opening or
closing of which seems determined by a circular membranous
surface situated obliquely at the base of the point.

Towards the posterior extremity the main tracheae approach
one another, and as at the head, pierce the epidermis, but together,
and in the central line, frequently forming a double wart-like pro-
tuberance. Each tube here terminates with a circular or oblong
ring of chitin, within which a drum-like membrane is partially
surrounded by three chitinous ridges set in the ring radially. Each
of these ridges, being pierced by a slightly serrated slit, forms an
efficient valve for the admission or exclusion of air, regulated by
the tension of the circular membranes, and giving the larva com-
plete control over its respiration. The volume of air included
within the main trachea and its extensive branches is sufficient to
enable the functions of life to be sustained with but little incon-
venience, even when immersion in water precludes the possibility
of obtaining fresh supplies.

If, instead, the larva be placed in a cell only partially filled
with water, it will soon raise either the posterior or anterior valves
to a level with the surface, and thus resembles, in its method of
breathing, the larvae of the genus Eristalis.

A curious adaptation of the breathing process of the larva
may be observed if a young and transparent specimen be kept in
a shallow vulcanite cell, covered by a loose glass, for several days.
It will do perfecdy well without food, but should be exposed to the

ENEMIES OF APHIDES. 37

air by removing the cover each day for a few moments, and drop-
ping upon it a single drop of water from a glass rod. The larva
will then extend itself, and if viewed under a magnifier will be
seen to draw in air through the piercing organ, bubble after bubble
passing down the oesophagus and accumulating in the stomach.
In this way only can the pharyngeal and oesophageal passages be
traced in the living larva.

From each of the main tracheal trunks large branches are
thrown off to every segment, and especially to the surface of the
flask-shaped posterior end of the circulatory vessel ; to the head,
numerous loops and curves being here interposed, in order to
allow of the invagination of the parts without stopping the flow of
air; and lasdy, to the nervous ganglion (/, Fig. i, PI. III.), situated
on the ventral side behind the head.

To ensure the continual supply of oxygen to this important
organ, each main branch from the tracheal trunks sends off at a
point not far from its commencement a small tube which passes
direct, generally following the course of a nerve thread, and without
branching, until it reaches the surface of the ganglion, where it
breaks up into numerous fine vessels. These tubes are shown at
k, k, Fig. I. About the head also a complex and duplicate system
of looped and connected tubes (/, m, Fig. i) provide against any
check or hindrance to the supply of oxygen from the movements
of the larva.

The Organs of Special Sense.

So far as my observations go, these are to be found in the pair
of double palpi situate above the mouth, and, in a pair of minute
organs, in the edges of the upper part of the mouth.

The palpi have already been mentioned as placed on two pro-
tuberances above the upper end of the opening of the mouth.
Two are found on each side, placed obliquely side by side, and
although the structure of the lower part of the organs appears to
be identical, the organisation of the corresponding apices on each
side is so different as to suggest considerable difference of function.

The outer papillae on either side is rounded at its extremity,
and provided with five minute circular openings, each encircled
by a chitinous ring, and 1 think provided with a transverse mem-

38 PREDACIOUS AND PARASITIC

brane. The effect is that of minute tubercles set irregularly on
the papilla.

The inner papilla on each side terminates in a single tubercle,
of less diameter than the papilla on which it is set, and in shape
like the extremity of a sausage. In some of my specimens these
tubercles appear to be set with a few short spines ; but in others
three or four very minute bladder-like structures are visible, pro-
jecting from the tubercle, so close together as to impinge on one
another.

It is impossible to predicate, in the slightest degree, as to the
precise function of these organs. I have some reason to think
that one or other of the pairs is of an olfactory nature, and ana-
logy would lead us to expect that one or both pairs should be
endowed with a sense of touch. That they are the seat of some
active perception of importance is shown both by their position
and by the nerve-fibres, which under favourable conditions may
be observed to pass into the base of the papillae.

Alimentary System of the Imago.

The entire alimentary system, from the proboscis to the rectum,
with the various glands forming its immediate appendages, is
shown on PL IV. at Fig. i. The drawing from which this plate
is taken was made from dissections of Eristalis tenax, this genus
presenting many advantages for the purpose in comparison with
the more delicate Syrphus luniger or others of the same genus.

The internal structure of the former insect differs so little from
that of the aphidivorous genera, that it may be fairly taken as
conveying to the reader all the important characters of the latter,
while the larger size and tougher nature of the various organs
enables them to be dissected and represented with a completeness
almost impossible of attainment if the excessively minute and
delicate viscera of S. luniger or similar species had been employed.

The principal difference in structure exists in the proboscis,
and in order to enable the reader to form a correct idea of that
organ as it is found in the genus Syrphus^ an outline drawing on a
small scale is given on the same plate at Fig. 2.

The proboscis of Eristalis h longer and of more substantial and
horny structure than that of Syrphus. As in the Muscid(B—\.\iQ

ENEMIES OF APHIDES. 39

anatomy of which the Syrphidse nearly approach — the organ con-
sists of three joints, corresponding to, or rather modifications of,
the three anterior segments — a^ b, c. The foremost, ^, consists of
a pair of membranous lobes of somewhat triangular shape, each
of which is divided, on its outer side, about the^ middle of its
length by a deep cleft. Each lobe is provided with a series of
channels, known as "pseudo," or "false tracheae," and consisting
of a number of parallel membranous grooves, to which a vast
number of incomplete rings give a semblance of tracheae. These
channels arise posteriorly from a transverse channel of similar
structure, larger in size, and placed at only a slight obliquity to
the central line of the proboscis.

Each lobe is supported by a curved chitinous arm, taking its
rise in the mass of muscles at the base of the second or middle
joint, and between these supports a pair of oblong chitinous plates
attached one to either lobe, from the extremity of the longitudinal
hollow on the upper side of the second joint, in which the ligida
(d), labium fej, and maxillce. f/, f) lie concealed.

The second joint (b) consists of two more or less substantial
chitinous processes, which support the muscles on the ventral
aspect, and between which, on the dorsal surface, is the channel
above mentioned for the reception of the tongue and its append-
ages. These are attached by membranous and tendonous connec-
tions at the base of the second segment, the apodemes of the
maxillae extending to the ventral side of the pharynx in the third
or basal joint.

The slender, acute, chitinous tongue, d^ forms with the labium,
^, which is furnished at its extremity with several comb-like pro-
cesses, a hollow tube, which is continuous posteriorly with the
pharynx, and which receives and passes on the food obtained by
the suctorial lobes. This will be further referred to in the next
section, when the food will be considered. Near the extremity of
the tongue is the opening of the salivary duct, which, arising; from
the salivary glands, is continued through the strong, triangular
chitinous structure, n^ of the third joint, which encloses the
pharynx. The second joint and the suctorial lobes are amply
supplied with the necessary air by extensions of the delicate
tracheal sac, composed of a crape-like membrane, and situated on

40 PREDACIOUS AND PARASITIC

the ventral side of the basal joint. Arising from the thickened
folds at the base of the maxillae, and belonging to the basal rather
than the intermediate joint, are a pair of labial palpi, g, presenting
a somewhat lanceolate appearance in Eristalis^ but in Syrphus
more club-shaj^ed, and resembling the same organs in the Mus-
cidce. They are covered closely with minute bristles and sparsely
with longer hairs, one or two of especial length and size arising
from the apex.

The third or basal joint, <:, consists of the folds of integument
surrounding the triangular chitinous structure forming the founda-
tion of the whole proboscis. These folds are continuous with the
integument of the fourth or antennal segment, which is in imme-
diate proximity to the facial opening, in which the proboscis lies
hidden when at rest. This segment contains the muscular
apparatus by which the chief movements of the proboscis are
accomplished, consisting mainly of five pairs of muscles attached
to the above-mentioned chitinous framework. It also contains the
tracheal sacs, or air reservoirs supplying the organ, and gives
passage to the prolongations of the cephalic ganglion which inner-
vate the muscular system. The triangular framework of chitin, //,
consists of a pair of thin plates, thickening on their ventral edges
to solid ridges, between which passes the pharyngeal tube. The
whole structure is anchored by means of two projecting processes,
or apodemes, in oval muscular masses, and between them issues the
continuation of the pharyngeal tube forming the oesophagus (i, i).

The oesophagus consists of an extended narrow tube, which,
bending sharply at its commencement, pierces the cephalic
ganglion, and ends in an enlargement just above the proventricu.
lus or gizzard (;//), where are situated the muscular valves control-
ling the passages to the sucking stomach or crop {k) and to the
digestive stomach (I) respectively, y

The appearance of the oesophagus, when viewed in dilute
glycerine under a ^-in. objective, is sufficiently remarkable. The
internal surface is covered with bristles, somewhat irregularly
placed and generally pointing downwards. These take their rise
in the third or membranous coat, which is insoluble in potash,
and is continuous with that of the pharynx and the proboscis.
The two outer coats of the oesophagus consist of circular and

ENEMIES OF APHIDES. 41

longitudinal muscular fibres respectively, giving it exteriorly a
rugged aspect, and the membranous coat bears on its interior
surface a lining of epithelial cells. The passage towards the crop
or sucking stomach is shown at k, and here the circular fibres have
become few, while the longitudinal and membranous coats are
developed, until the crop itself is reached, when the muscular
bands interlace in all directions, especially about the centre. The
organ shown in the figure is collapsed or empty, but when occupied
with food it presents the appearance of a seamless, distended bag,
around the middle of which a broad constricting band divides it
into similar hemispherical parts. Its surface when distended is
smooth and free from corrugations, but displays the numerous
crossing bands of muscular fibre, by means of which the food is
regurgitated, to find its way to the proventriculus, m, and the
" chyle stomach," or digestive stomach, /. The proventriculus is
embraced by the upper portions of a pair of sacculated glands,
«, n, which secrete some gastric or other fluid, to assist in the
digestive operation.

The digestive stomach, /, which presents no points of special
interest, opens by a muscular neck more or less developed into
the upper intestine, p, which in the figure is distended by food,
and which at its lower end receives the secretions of the four
elongated hepatic glands, g., g. These glands are objects of great
beauty. The arrangement of the nucleated cells on either side of
the tube, which constitutes their main structure, gives them the
appearance of a regularly knotted rope, and frequently the whole
organs are of a brown or beautiful purple colour.

At the extremity of the intestine. a powerful muscular valve
controls the passage of food to the lower intestine, r. This
intestine is much stouter in its structure, the rugose outer surface
presenting at times an almost sacculated appearance, and at its
lower end it passes into the rectum by an internal muscular con-
traction not readily observed, as the external wall is often not
contracted. The rectum (v, v) is noticeable for the great
development of the renal organs (^, t), which are found, four in
number, in an ovoid enlargement at s. These organs are of great
interest, and may readily be obtained from a recently killed
insect. They will be fully described and illustrated in the next

42 PREDACIOUS AND PARASITIC ENEMIES OF APHIDES.

section, together with the organs of generation, and observations
upon the food found in the viscera of some species.

5>

EXPLA.NATION OF PLATES III. & IV.

Plate III.

Fig. 1. — Details of anterior segments of larva of S. luniger. a,
Piercing organ. 6, Pharynx, c, Palpi, d, cZ, d, Muscles
controlling the movements of mouth parts, e, Mass of mus-
cular fibres surrounding pharynx. f, One of the hooks.
, • g, g. The anterior inlets of the main tracheal trunks, h, h.
i, The nervous centre, consisting of many combined
ganglia, and giving off numerous nerve-threads (k, k) to the
different segments. I, Tracheal loops to provide for circula-
tion of air during the invagination of mouth parts, m. Cross
tracheae connecting main trunks with tracheae of nerve centres.
These are duplicated, n, Salivary glands, o, (Esophagus.

,, 2. — Chitinous portions of piercing organ.
3. — Points of same, enlarged.

4. — Muscle surrounding same, the pharynx being shown by
dotted lines.

,, 5. — View of sucking organ, with blades opened.
,, 6. — Point of piercing blade, much enlarged.

,, 7 and 8. — Posterior terminations of tracheal trunks, showing
structure of chitinous valves.

,, 9. — Under view of front parts of larva partially evaginated.
a, a, 6, h, The frontal palpi with their papillae, c, c. d, The
cleft of the mouth, e. The extremity of the piercing organ,
just visible. /, Pair of palpus-like organs on the borders of
the mouth, g, Border of mouth, h, h, Chitinous hooks.

Plate IV.

Fig. 1. — Alimentary system of Syrphidcb as illustrated by Eridalis
tenax.

d, b, c. The three joints of the proboscis, d, Tongue,
e, Labium. /, /, Maxillae, g, Labial palpi, /i, Pharynx.
i, CEsophagus. k, Passage to crop, k', Crop empty of food
and collapsed ; a few grains of pollen are visible within.
I, Stomach, m, Proventriculus or gizzard. n, ?</, Secretory
organs delivering gastric or other digestive fluids to the pro-
ventriculus. 0, o, Salivary glands, which have their ultimate
outlet in the tongue. It has been impossible to trace the
ducts throughout, p, p, Intestines distended with food.
q, q, Hepatic vessels discharging into lower end of intestines,
r, r, Lower intestines, v, v. Rectum, s, Enlargement of
rectum containing the renal organs, t, t. u, u, Traclieal
vessels supplying air to renal organs.

2.— Proboscis of Syrplms luniger, with lobes extended and viewed
obliquely. The same lettering applies as to Fig. 1.

>>

Journal of Microscopy 3^^^ Ser. .Vol. 5. Pi. 3

H. C. A. Vine ad naf. del

F. Phillips, Sc.

Journal of Microscopy 3^^ Ser Vol. 5. PL 4

H C. A l/ine, 3d, naf de/

r. Phi Hips. Sc.

PLATE Y.

[ 45 ]

Ifrom 2)u6t to 2)u0t

H C^cle ot %iU.

By J. Sidney Turner, M.R.C.S., F.L.S*

AS medical men, we are ever face to face with Nature's
problems, and are constantly being called upon to unravel
some of her deepest mysteries. It is our task to repair
her working machinery when it becomes rusty and out of gear — to
deal with the abnormal rather than the normal. I have therefore
chosen a subject which contemplates the natural order of things,
and which may, at least, afford us some change of thought. It
will necessarily be but a brief sketch of what might well be made
to 'fill a volume.

Man has been tersely defined as a " cause-seeking animal."
The Alpha and Omega of life have ever been fascinating problems
for speculative thinkers, but the truest philosophy is that which
seeks only to discern the knowable.

The Book of Nature, written for all time and all people, is
ever open to us, and, although it at first seems to be written in an
unknown tongue, like some richly-illuminated old missal, wherein
we can only admire the form of the letters and the beauty of the
colouring, it requires no translation but that which the earnest
student, if guided by love of truth, may accomplish for himself.
Thomas k Kempis says, " If thy heart be right, then will every
creature be to thee a mirror of life and a book of holy doctrine."
No two persons see exactly the same world ; it is greatly in our
power to make it a Heaven or a Hell. Happy indeed is he who
seeks the pleasures of life — not the fleeting ones that perish, but
those intellectual pleasures that have in them germs for future
development. Can we do better than inculcate in our youth a
love for Nature ? Be sure that, where such exists, tender chords
of sympathy will be found ever ready to vibrate in harmony with
the Eternal Truth.

Who amongst us is not the better for having some hobby ?"
Who may not, in some humble way, add to the growth of that

* Address given at the Fiftieth Annual Meeting of the South Eastern
Branch of the British Medical Association, June 13th, 1894.

46 FROM DUST TO DUST.

great tree of knowledge, planted as a seed by primeval man,
tended and trained through long ages by the loving hands of those
devoted to its culture, and watered, aye, sometimes by the blood
of martyrs — for science has had its martyrs — until it has grown
into that sturdy giant which it is now our privilege and duty to
tend ! May we guard this sacred inheritance with jealous care,
and add new growth to that good old stem which enshrines the
labour of many great men, who though long gone from us, are
ever present in our life's work !

Aristotle, the father and creator of Scientific Biology, with the
clear insight of his philosophic mind, discerned in organic nature
an ascending complexity from the vegetable kingdom up to man.
Strange indeed that this bud of thought should have remained
dormant for about 2000 years, until Lamarck, Goethe, Erasmus
Darwin, and, above all, Charles Darwin and Alfred Russell Wallace
gave it vigour to unfold and bloom as the fairest flower of modern
philosophy. Great and far-reaching as this Theory of Evolution
has been, it yet failed to explain many of its own phenomena.
It traced, step by step, the gradual development of the higher
from the lower organisms — or from ancestors which were common
to both — but, it hardly took sufficient account of the work effected
and still being done by micro-organisms, without which all life
would be impossible, and which have certainly been amongst the
principal agents and factors of Evolution.

For a knowledge of these micro-organisms, and of their power
for good and evil, this and all future ages will owe a deep debt of
gratitude to Davaine, Pasteur, Lister, Koch, Metschnikoff and
others, who have explored for us this hitherto unknown world of
life ', a world within a world, and, may be, the very centre where
life began, and whence it radiates, connecting all life together as
in an endless chain. It seems that we have got at least one step
further towards the solution of the mystery of Life.

The thoughts of many minds seem for a time to float about,
as nebulous theories, in the atmosphere of the scientific world,
until some one with master mind condenses and crystallises them
into a shape and form, to which the breath of his genius gives
energy and life. When any new and great discovery is made, it
at first seems to explain so much and to open up so many new

FROM DUST TO DUST. 47

vistas of thought, that we are apt to imagine we have found the
master-key to unlock all the secret drawers of Nature, but she still
keeps many of them closed to us.

We are accustomed to speak of the different sciences, though
really but one science exists, which, like a civilised state or a com-
plex organism, requires inter-communication between all its parts
to preserve its corporate life. Science, like all other organised
complexities, tends more and more to become specialised in its
several parts ; so that We get many segregated facts and induc-
tions, until a Darwin or a Lister arises to aggregate, collate, and
deduce some general principle from them.

Natural "Science seeks to show not only what a thing />, but
what it does^ and deals with all the conditions of life, as well as
life itself. Geology treats of the formation and inorganic develop-
ment of the earth, that is to say, of the conditions of life existence.
Anatomy, Morphology, Histology, and Embryology are so inti-
mately connected with Physiology, and the latter with Chemistry
and Physics, that it is impossible to define their boundary lines.
These Sciences, combined with a knowledge of the external
requirements necessary to existence, teach us to know the positive
conditions under which life is carried on ; whilst Pathology tells
us the negative conditions, which are inimical to healthy life, pro-
ductive of an alteration of vital properties, and death. Amongst
all these Sciences, Chemistry and Physics alone contemplate things
in a state of rest, and bring us nearer to the ultimate analysis of
matter. The Physicist shows us how gravity, attraction, pressure,
and the vibrations of light, heat, and magnetism influence matter ;
and the Chemist, by analysing and combining its elements, teaches
how inorganic matter can be built up, and brings us to the very
threshold of organic life. Well may these sciences be wedded and
work together as Chemico-Physics ! Such unions between all the
Sciences, with increasing knowledge, will more and more take
place, as their action and interaction are better understood. An
advance and stepping forward out of line takes place, first in one
and then in another science, so that, eventually, each Science is
enabled to cast side-lights upon others, and to receive light from
them in return.

Bacteriology, the youngest of all the Sciences, has of late years

48 FROM DUST TO DUST.

made such rapid advance, and has shed so much light, that it may
be said to have illumined all other Sciences connected with life
upon our planet; to have elucidated some of the chief phenomena
of Agriculture ; and to have placed many of our manufacturing
industries, such as those of silk, wine, etc., upon a rational footing.
It furnishes us with many friends, as well as many foes, but happily
the former predominate.

Nature seems not only anxious to produce, but to destroy.
There is a Shiva as well as a Vishnu, as the Hindu philosophy
teaches ; and it is probable that every animal and vegetable organ-
ism has a Shiva near at hand, when the scales, which Brahma
holds, trend their beam towards that side which points to the
setting of life's sun. The maintenance of the equilibrium between
the force which integrates and builds up, and that which disinte-
grates and pulls down, is the mystery of life ; its loss is the
mystery of death. Between these two forces lies the path of
progress and the way of endless evolution, the purpose of which
is the inscrutable secret. Life and death are equally necessary to
the fulfilment of that end for which the former was brought into
existence. Death is necessary for rejuvenescence of species and
progressive evolution ; according to Professor Weismann it is an
acquired characteristic of the Metazoa ; and the only acquired
character which he concedes to be hereditary.* Amongst unicel-
lular organisms — Protozoa and Protophyta — there is no natural
death, whilst the conditions favourable to their lives are present ;
they can multiply by fission, so that, as all the body material is
used up in the process, there is nothing left to die ; or, as Weis-
mann puts it, " There is no death because there is no corpse."
These Protozoa and Protophyta (or, as Haeckel calls them. Pro-
tista) produce in the Metazoa both life and death.

. The origin of life in the eternal past, as well as the end of life
in the eternal future, is sealed to us ; it is not, however, beyond
the aim of students of Biology to study the only eternal that our
finite sense is capable of understanding — the Eternal Present —
and to see how the wheel of life revolves.

* In a letter from Professor Weismann, dated August 21, 1894, he says : —
" You seem to believe that I take death for an acquired character, but death
is certainly not a somatogenous character, but a blastogenous one. So there is
no doubt that it must be transmitted," etc.— J. S. T.

FROM DUST TO DUST. 49

How or 7vhe?i life first originated is not for us now to consider;
suffice it to say that even Tyndall, who fought such fierce battles
with Bastian and Pouchet on the question of Abiogenesis, has told
us * "that, as a believer in the nebular hypothesis, he is logically
bound to believe that spontaneous generation did come about
some time;" and Haeckelf thinks that it may still be taking
place in such organisms as Bathybius Haeckelii. This moneron,
found at a depth of 2,000 to 4,000 fathoms, was discovered and
described by Huxley, but of the organisation of this " protoplas-
mic slime " there is some doubt, though Dr. Emil Bessels,J an
excellent observer, states that he has studied it in the living con-
dition. Under any circumstance, whether it be organised or only
a gelatinous precipitate of sulphate of lime, its spontaneous gene-
ration must be an assumption.

The question where life first originated is more easily dealt
with, and on this point most naturalists are agreed that the ocean
was the original home of all life. During a long period of the
earth's history there was practically only pelagic life, the conditions
of which are so simple that it is easy to believe that the first dawn
of life appeared there. Modern science has discovered quite a
new fauna and flora in the organisms of the surface, such as Tri-
chodesmium^ PyrocisHs^ Protococcus^ the Coccospheres, Rhab do spheres,
the free-swimming algae and bacteria. Whether or no the bacteria
in sea-water perform the function of fixing the nitrogen of the air?
so that it can be utilised by pelagic algse, in the same way as nitrify-
ing organisms are known to do on land, has yet to be discovered;
but it is clear that the teeming myriads of marine animals, the
most conspicuous of which are all carnivorous, must get their
nitrogen from somewhere. The small amount of debris coming
from the land, and the very limited supply of vegetable food which
the littoral shore can afford, could never support so vast a fauna,
far larger indeed than that of the land.§ On the earth's surface we

* Natural Science, Jan., 1894. Tyndall, by Prof. Huxley.

t E. Ilaeckel, The History of Creation, v. i., p. 344.

X Jena Zeitschrift, v. ix. , p. 277.

§ Natural Science, October, 1894, p. 242. Review of Prof. W. K.
Brook's paper m Journal of Geology, August, 1894 : —

" In a«few vivid pages we are shown how the ocean is almost destitute of

Inter a nal Journal of Microscopy and Natural Science.

HiRD Series. Vol. V. e

50 FROM DUST TO DUST.

have a vast vegetable kingdom, whose grand and mysterious func-
tion it is to turn inorganic matter into organic life, by the action
of rootlets and spongioles upon nitrogen, salts, and minerals ; and
by that of the chlorophyll of the cells upon carbon, under the
influence of the sun's light. What a mystical moment it must be
when a particle of inorganic matter suddenly, in an instant,
becomes part of an organic existence ! Could we but follow
any single particle on its journey through life and back again to
its former state as an element, we should know not only its own
history, but that of the greater part of the universe.

Herbert Spencer* in " Principles of Biology" says — ''As in
all cases we may consider the external phenomena as simply in
relation, and the internal phenomena also as simply in relation,
the broadest and most complete definition of Life will be : — The
continuous adjustment of inter^ial relations to external relations. It
will be best, however, commonly to employ its more concrete
equivalent — to consider the internal relations as 'definite combin-
ations of simultaneous and successive changes ; ' the external
relations as ' co-existences and sequences ; ' and the connection
between them as a ' correspondence.' "

t " Each advance to a higher form of life consists in a better
preservation of this primary correspondence by the establishment
of other correspondences." ..." Perfect correspondence
would be perfect life."

For life to have existed at all, the conditions of life-existence
must have been first present. We are accustomed to use the

plant-life, how its flower gardens are only stocked with animals, and how its
very herbs and lichens are corallines and sponges ; we learn how the vast
animal armies of the sea attack and devour other animal armies, but have never
a plant for their forage ; and thus by descending steps we are brought to the
conclusion that ' the basis of all the life in the modern ocean is found in the
micro-organisms of the surface,' lowly animals and plants so abundant and
prolific that they meet all demands. These minute pelagic creatures must
have been the first to exist, and where they first appeared, there they have
since remained, undisturbed by varying environment or the stress of com-
petition, and therefore retaining their primaeval simplicity."

* Herbert Spencer, Principles cf Biology, § 30.

t Herbert Spencer, First Principles, § 25.

FROM DUST TO DUST. 51

terms " adaptation " and "the survival of the fittest." We probably
all know what is implied by these terms, but it will be as well to
bear in mind that organisms do not adapt nor fit themselves to
their environment, but they are compelled by the conditions of
their environment to harmonise with it, or to die : in short, they
are conditioned by their enviroment. A better term than "survival
of the fittest " has been suggested in " the survival of the least
unfit." It is not always, therefore, the fittest organisms which
survive, but those which are best adapted to their external relations
by the conditions which environ them.

When we speak of Life we must not forget that, besides the
life of the individual, there is a continuous life from individual to
individual, stretching back to its most remote first appearance
upon our planet. The Evolution of Life, in its broadest sense, is
in a chain, the links of which are composed of cyclical existences.
This chain may be compared to the rolling wave, made by the
impetus of separate particles of water, each of which moves in a
cycle and returns to its former position of rest.

* " An entire history of anything must include its appearance
out of the imperceptible, and its disappearance into the imper-
ceptible." in order to have a beginning we must therefore assume
that the Earth was composed of the primary rocks. Upon these
solid rocks the action of heat, cold, rain, and frost has been and
is continually causing degradation, erosion, grinding, denudation,
and alluviation. To their weathered products we apply the name
of " Soil." The various component parts of the earth-surface are
thus being continually mixed up, so that we have a Mechafiical
Integration, which very quickly passes into a Chemical Composition.

Recent Science has shown that this " soil " is incapable of sus-
taining vegetable hfe, even in its lowest forms, until it has under-
gone some change by exposure to the air, or, rather, to what the
air contains. If we take soil and sterilise it — a very difficult thing
to effect completely, except by burning it — nothing, with the
exception of certain micro organisms or nitro-monads, will grow in
it. It is true that certain spores and seeds will germinate, but
only thrive for so long as they can live upon the nourishment

* Herbert Spencer, First Principles, § 93.

52 FROM DUST TO DUST.

which has been stored up, within the seed itself, by the mother
plant. These nitrifying bacteria, on the contrary, seem to thrive
best in a medium devoid of all organic matter ; and this is of the
greatest importance in the economy of Nature. Prof. Frankland*
has kept them alive for four years in a purely mineral solution ;
and Winogradsky proved that they not only flourish, but multiply
and build up living protoplasm, in a solution from which organic
matter has been rigorously excluded. Other bacteria transform
iron and iron-peroxide into oxide of iron ; whilst others oxidise
sulphuretted-hydrogen, and transform it into sulphur and sulphuric
acid, but as these are inimical to vegetable and animal life we
need not speak further of them.

Prof. Stoney asks : — t" Whence comes the vital energy of the
innumerable bacilli which are excluded from the direct influence
of sunlight, and why are these organisms all extremely minute ? "
There are some bacilli {e.g.^ the nitrifying bacilli of the soil) which
seem to thrive entirely upon mineral food, and not only so, but
perform their functions while completely removed from the sun's
rays. The manufacture of protoplasm and other complex com-
pounds from inorganic matter involves a considerable amount of
energy, and the bacilli must somehow obtain this from the sur-
rounding gases and liquids; Prof. Stoney regards it as conceivable
that the energy may be imparted to the organisms directly by the
impact of the more swiftly moving molecules of these gases and
liquids ; and if that be the case, then the necessity for the exces-
sive minuteness of the bacilli — scarcely more than molecules —
is explained.

Nitrogen is quite as necessary for plant-life as for that of the
animal. It exists in the soil, even when it is not manured, and
largely, as we know, in the atmosphere. It is only recently, how-
ever, that we have any certain knowledge of the means whereby
the free nitrogen of inorganic nature becomes part of a living
body. That plants do not obtain their nitrogen from the air by
the action of their leaves has been conclusively proved, and it has
now been clearly established that those which are not insectivorous

* Prof. Percy Frankland, Our Secret Friends and Foes, p. Z^.

t Sci. Proc. Roy. Dublin Soc, n.s., v. viii., pp. 154, 156, quoted in
Natural Science, v. iii., p. 252.

FROM DUST TO DUST. 53

obtain it by means of nitrifying bacteria. Darwin has shown that
Drosera, Dioncsa muscipiila^ Utricular ia^ and other insectivorous
plants obtain their nitrogen from insects, larvae, and other small
organisms, which are caught in their traps.

Schloesing and Miintz, in 1877, demonstrated that a living
ferment was necessary for the production of nitric acid and nitrates
in the soil ; but it was due to the researches of Prof Percy Frank-
land and Mrs. Frankland, Warington, and Winogradsky, that the
complete knowledge of the process of nitrification was obtained,
and that two different bacteria were necessary to accomplish it,
one of which converts ammonia into nitrous acid, when the other
takes up the work and produces nitric acid in a form which can be
assimilated by plants. These have now been completely isolated,
and it is remarkable that the nitric-acid-forming bacterium was first
found in a sample of soil taken from a region near the great salt-
petre layers of Chili. European soils contain much smaller
quantities of nitrates than those of South America or Africa, but
this has been accounted for by the much greater rainfall in Europe,
which removes the soluble salts from the surface of the soil, whilst
the dryness of the tropical climates of Chili and Peru allows them
to accumulate. It is quite conceivable that the rapid growth of
vegetation which occurs in an Arctic or Alpine summer, may be
due to the accumulation of nitrates in the soil, which has been
kept dry and comparatively warm by the snow for so many
months. /

We all know what an immense benefit the importation of
nitrates has been to agriculture, and also that manufactured
nitrates have been of some use. It remained, however, for
Science to show that, besides importing the nitrates, we also
imported the nitrifying organisms, which continue to fertilise our
lands (even after the nitrates themselves have been used up) by
acting upon the ammonia in the manures, which we afterwards
supply to them. Hitherto our methods of cultivation have been
empirical, and one of the great maxims has been " to expose the
soil to the air.'' Empiricism, the result of well-observed experi-
ence, has nearly always proved right knowledge. Science explains
the knowledge obtained by empiricism, develops it, and by deduc-
ing general laws and principles gives it wider scope of action.

54 FROM DUST TO DUST.

That certain plants, such as peas, beans, vetches, sanfoin, and
clover, instead of impoverishing the soil, possessed the power of
enriching and rendering it more productive for other crops, has
been a well-recognised fact for many centuries. In the earlier
Rothamstead experiments, previous to 1861, it had been ascer-
tained that while the higher plants, as a rule, absorb no nitrogen
from the air, except the small amount to be obtained from nitric
acid and ammonia after thunderstorms — the leguminous plants
were able in some way to obtain it. Dr. Wilfarth and Professor
Hellriegel discovered that their roots, grown in fertile soil, were
covered with nodules, and that these nodules were caused by the
presence of certain bacteria {B. radickola), which, however, were
not parasites, but lived with their plant-host in true symbiotic
relationship. They borrow from the plant the necessary hydro-
carbons and supply it with nitrogen, which they assimilate from
the air circulating in the soil. It has been proved, moreover, that
these bacteria are the cause of the nodules appearing on the roots
of the plants; for, when the i)lants are grown without the bacteria,
they cease to produce these swellings on their roots, which are so
remarkably rich in nitrogen and swarming with bacteria.

Prof. Nobbe confirmed these results, and found that a similar
symbiosis exists between microbes and Robinia, and he further
discovered that each plant has its own particular microbe, and did
not thrive so luxuriantly when the microbe of another plant was
substituted for its own. Thus, besides a ge?ieral nitrification of the
soil constantly occurring for the maintenance of all plant life, there
appears to exist a special arrangement between certain plants
and certain bacteria, for their mutual benefit. Whether or no
these microbes can be made to adapt themselves to other hosts,
in course of time, is being made a matter of experiment by Dr.
Schneider, of Illinois.

Numerous instances are mentioned by Sir John Lubbock,
Frank, and others, of symbiosis or commensahsm of certain fungi
and some of our forest trees, such as the Beech and Pine, which
thrive only when their roots arc in contact with Mycorhiza and
other fungi ; and, although it was formerly supposed that the
fungi were attacking the roots, it is now considered that the tree
and the fungus mutually benefit each other.

FROM DUST TO DUST. 55

In the well-known instance of lichens, the algal cells are
nourished by the hyphal tissue of their fungal overgrowths, which
weave themselves round and enclose them, and supply nitrogen
and inorganic materials; whilst the algal cells, m turn, convert
the carbonic acid of the air into organic compounds, such as
starch, which the fungus makes use of The fructification in
lichens is produced by these fungal overgrowths ; and it is inter-
esting to observe that in the proximity of large towns they do not
attain to this stage, because the smoky air is inimical to the growth
of the fungi. No doubt many of us have observed the (so-called)
" fairy rings " on our hills and downs ; these are produced by the
better and more vigorous growth of the grass, owing to the excess
of nitrogen affon^^ed by the fungi, which composed the ring of the
previous year.

■ According to the recent experiments of Schloesing and Lau-
rent,* various mosses and minute algse (Confervae, Oscillatorige,
etc.), which usually develop on the surface of the soil, also absorb
nitrogen from the air, which, after having been assimilated to the
soil, goes to feed the higher plants. Whether or no these lower
plant organisms take the nitrogen direct from the air, or are
indebted to bacteria for their supply,t we do not at present know,
but that the higher plants are dependent upon bacteria and the
lower fungi for their nitrogen is clearly established. There is every
reason to believe that nitrifying organisms supply the lower fungi,
and that these, in turn, associate with algae to form lichens, and
afford nitrogen to them. \ Thus we ascend by the gradual increase

* Comptes Rendtis, 1 89 1, t. 113, p. TJ^J.
t See Nature, July 19, 1894, under Notes commencing "Frank and others."

ij: Nature., July 19, 1894, p. 276. — " Frank, and afterwards Schloesing
and Laurent, showed that soil containing bacteria and algae can fix free nitrogen
in large quantities ; their experiments, however, did not decide whether algae
alone are capable of doing this. In order to answer this question Kossowitsch
has estimated the amount of nitrogen present in a nutritive soil before and
after the growth of pure cultures of two kinds of algae — Cystococcus and
Stichococcus. In neither case was any sensible increase of nitrogen detected ;
so that it appears that neither of these algae alone have the power of fixing free
nitrogen. Cystococcus, even when mixed with pure cultures of the bacteria
which enable the Leguminosie to assimilate free nitrogen, was found powerless
in this direction ; whereas a mixture of soil-bacteria and Cystococcus, which

56 FROM DUST TO DUST.

of available plant food to the higher forms of vegetable life, from
which the Aniijial World derives its sustenance.

There is, however, really no boundary line between the vege-
table and animal kingdoms ; the distinction which Cuvier and
others made between them all break down under examination.
Some organisms, such as Mycetozoa, appear to belong, at different
stages of their existence, to both kingdoms. Broadly speaking,
however, plant life is nourished and sustained from without; whilst
animal life is supported by digestion of food from within. In
other words, plants have their roots outside, and animals have
theirs inside themselves ; except those lower organisms which
obtain their food from the fluid media in which they are bathed,
and others which lead an entozoic and parasitic existence, It
became necessary for those animals which were attaining a higher
complexity of organisation, and had to seek food by moving about
from place to place, to take their roots with them. This com-
menced by what is known as "gastrulation," passing through every
stage, from mere invagination of the ectoderm to the gastro-intes-
tinal system of the higher mammals. It also became necessary that
the higher animals should be, to a great extent, independent of
the immediate assistance of external ferments ; consequently they
have acquired the power of digesting and assimilating the organic
proteids, carbo-hydrates, and fats, by means of their own ferments,
such as Ptyalin, Pepsin, Trypsin, Amylopsin, and the Succus
Entericus. These are unorganised ferments, which were formerly
supposed to exert merely a chemical action. They, however,
possess the character of living things, except that they cannot be
identified as living organisms.

also contained a small amount of other algce, had the power of fixing free
nitrogen to a large extent. The same author also describes a number of
experiments with heterogeneous mixtures of algae and bacteria, and shows how
in each case the capability of fixing free nitrogen is greatly increased by the
addition of dextrose to the nutritive substratum, from this, and also from the
fact that such mixtures of algae and bacteria, which are capable of fixing free
nitrogen when exposed to light, cannot be shown to assimilate it in the dark,
he concludes that although in no case has it been proved that algse by them-
selves possess the power of fixing free nitrogen, yet they are in a symbiotic
relationship with the nitrogen-fixing bacteria, and he regards it as probable that
these latter draw on the assimilation products of the algaj to supply the carbon
they require in growth."

FROM DUST TO DUST. 57

Prof. Halliburton, in his recent work, The Essefttiah of Chem-
ical Physiology, says — "The gastric juice is antiseptic ; the ])an-
creatic juice is not. . . . It is often difficult to say where
pancreatic action ends and bacterial action begins, as many of the
bacteria that grow in the intestinal contents, having reached that
situation in spite of the gastric juice, act in the same way as the
juice itself. Some form sugar from starch, others peptone, leucine,
and tyrosine, from other proteids ; while others, again, break up
fats. There are, however, certain actions that are entirely due to
these putrefactive organisms." It is a pity that the word "putre-
factive" is employed here, as it implies more than is really meant.
I need not enter into the details of the action of these intestinal
Anabiotic bacteria upon carbo-hydrates, proteids, and fats ; they
are carefully described in his book. Dr. Halliburton also tells us
how we are protected from an alkaloidal poison, called Choline,
by the bacteria which break it up into carbonic acid, methane,
and ammonia.

Dr. Alexander Houston,* in his report upon the Scott-Moncreiff
sewage system, states " that bacteria exist in sewage, which are
capable of peptonising solid organic matter, or, in other words, of
preparing it by a process comparable to that of digestion for its
final destination.

Thus far we have dealt with bacteria, which, as factors of
change, are friends rather than foes, and we have now attained
to the summit of life's wheel — where "perfect correspondence"
takes place by the " continual adjustment of internal relations to
external relations " — perfect metabolism — perfect life.

The processes of evolution have been synthetic, constructive,
ever and ever becoming more complex as we ascend. The links
which form the chain of life are made up of one or more species,
whose component members are continually filling the gaps left by
their predecessors fallen by the way. What appear to be the weak
links are made up of the greatest ; while those which are stronger
are made up of the smallest numbers. No single link must long
remain too weak or too strong, or the perfect work of the whole
chain will be impaired. If a link should become too strong in

* Nature, Report on Scott-Moncreiff Sewage System, by Dr. A.
Houston, 1894.

58 FROM DUST TO DUST.

numbers, its average is adjusted by diminished supply of food on
the one side, or by increase of its enemies on the other. There is
thus a constantly shifting equilibrium, to which we are accustomed
to apply the term — the balance of Nature ; and, by this, every
species is maintained at a working point. I must not, however,
pursue this interesting problem any further, but proceed to the
"facilis descensus," which we find all too easy.

We have now to consider micro-organisms in regard to their
nature as foes to health, as Pathogenic oxgdinhms producing Degen-
eration and Death. Leaving accidents out of consideration — and
these may be often the cause of the entry of pathogenic germs — we
may roughly define disease as a disturbance of vital phenomena,
using the word " vital " as symbolic of perfect life. It may be
some disarrangement of the alimentary or mechanical systems,
which, in many instances, will be found to depend upon some
remote bacterial action — such as, diarrhoea produced by souring
of milk, or ptomaine poisoning by preserved meat or vegetables,
or tubercular inflammation of a joint. We have also many diseases
caused by parasites of all sorts and sizes, from Taenia to Trichina
spiralis and Filaria. However, a great and ever-increasing num-
ber of diseases are now perfectly well ascertained to be the direct
result of pathogenic organisms. There is no need for me to
mention their names, as you are perfectly well acquainted with
them. I would like, however, to emphasise this fact — that disease
is not an "affliction," but, in most cases, the result of an ignorance
of, or a contempt for, those methods, which, for want of a better
name, we call '■ the laws of Nature." In other words, disease of
zymotic origin is " preventable ; " and it is a blot upon our so-
called advanced civilisation that it is not more prevented. Dirt
has been well described as "matter in the wrong place." Zymotic
disease is life in the wrong place.

After the stage of disruption which we call Death has been
reached. Putrefactive organisms are the factors of change, causing
organic to be broken uj) into inorganic matter, in the process
called Animal decompositio?i. We must not forget that the world
has many scavengers by sea and land, such as sharks, vultures,
hycenas, and many others ; but these serve but temporarily to
arrest organic matter in its downward course, and leave the work

FROM DUST TO DUST. 59

but very incompletely effected ; and our old friend Bacterium
iermo, or Bacillus proteus, as he is now called, ultimately finishes
the business. Were it not for this;, certain substances would assume
a state of rest, and be incapable of being again used ; whilst the
earth's surface would be littered and clogged wnth dead and useless
organic matter, and all life, as we now know it, would cease to exist.
Animal decomposition comes to an end only with the change of
the last particle of organic matter into the inorganic, when chemical
decomposition and mechanical dismtegration restore the mineral
and gaseous elements to the condition of being capable to live
again. It is quite possible that in some instances a " short circuit "
is made, but our present teaching tends more and 'more to show
that all life — as first life must have been — is built u[) from elemen-
tary particles, such as nitrogen, carbon, silicon, water, nutrient
salts or mineral food stuffs, such as the soluble sulphates, phos-
phates, nitrates, and chlorides of calcium, magnesium, sodium,
potassium, and iron ; whilst for plants living in the sea, iodine
and bromine are of especial importance. Fluorine, manganese,
lithium, and various other metals, such as alumina, found in the
ash of lycopodium, also enter upon their cycle through life by
means of plants.

Cyclical change thus appears to be the key-note which domin-
ates all the harmonies of Nature.

SUMMARY.

I have made the attempt to show how the study of Nature —
having especial regard to the phenomena of life — to which we give
the comprehensive title " Biology," embraces and binds all other
Sciences together.

How the thoughts of many minds have been crystallised into
that priceless pearl of knowledge, "The Theory of Evolution."

How the discovery, in our own times, of the hithero unknown
world of micro-organisms had thrown its light on this, and many
of life's deepest mysteries.

How the conditions of life existence — the formation of soil —
preceded all evolution of life.

How organisms turned inorganic material into protoplasmic
life, but

60 FROM DUST TO DUST.

That we were quite unable to conceive the first beginning of
life — how or when it originated — but that it was probable

That the ocean was the first home of life.

That the earliest differentiated forms of life appear as a rod
and a simple cell.

That the rod-form, or bacterium, was capable of thriving in
inorganic matter, and building up protoplasm for higher forms
of life to exist.

That — leaving the small amount of nitric acid and ammonia,
which some plants may, at intervals, obtain from the air after
lightning, out of consideration — these nitrifying bacteria are neces-
sary to produce a supply of nitrogen (which is a necessary constit-
uent of all protoplasm), for the growth and development of

plant life.

That inorganic matter by the action of the rod and cell forms
of life was started on its cycle through the vegetable kingdom.

That vegetable life supports animal life by means of unorgan-
ised yet vital ferments, provided by the animal economy; but that
the conversion of carbo-hydrates, proteids, and fats, is assisted by
many bacteria, to which I have given the generic name of Anabi-
otic, or builders up of life in contradistinction to the Katabiotic
bacteria, or destroyers of life, which we are accustomed to call
Pathogenic bacteria.

That bacteria were friends and foes ; and that many diseases
were produced by life in the wrong place.

That in such disease a conflict takes place between the rod
and the cell forms of life, in which, happily for us, the cell is often
victorious, though sometimes the reverse occurs, causing degenera-
tion and death.

That putrefactive organisms are beneficial to the world of life,
by restoring the mineral and gaseous elements to a form which can
be again utilised to create another world of life.

And, finally, that these bacteria are the factors of change both
in the evolution and dissolution of all organic matter.

Such is a brief outline only of this most interesting subject,
and no one more than myself realises how inadequate it is to explain
what we desire to know. I have striven to state as facts only those
that have been well proven, and to base deductions upon them.

FROM DUST TO DUST. 61

Aristotle said, " We must not accept a general principle from
logic only, but must prove its application to each fact, [for it is in
facts we must seek general principles, and these must always accord
with facts." "Prove all things ; hold fast that which is good."

It seems to me, however, that micro-organisms are the great

factors of change in the economy of Nature ; commencing their

work in the inorganic world, carrying it through the organic world,

and back again to the inorganic, where their task is recommenced,

and cycle rolls on cycle "down the ringing grooves of change."

These wonder-working micro-organisms, which render such
subtle service in the unseen world around us, would be well com-
pared to the Erdgeist, or Earth-spirit, in " Faust," who called
Nature " the living, visible garment of God."'"

" In Being's floods, in Action's storm,
I walk and work, above, beneath.
Work and weave in endless motion !
Birth and Death,
An infinite ocean ;
A seizing and giving
The fire of Living.
'Tis thus at the roaring Loom of Time I ply,
And weave for God the garment thou seest Him by."

Thus may we all work and weave

^ " Ad majorem gloriam Dei."

In a collection made by Captain W. G. Thorold in Thibet of
plants growing at elevations between 15,000 and 19,000 feet,
fifty-seven, or one-half, were found between 17,000 and 18,000
feet, five between 18,000 and 19,000 feet, and one, Sansiirea
tridactyla, at 19,000 feet. A large majority of the plants hardly
lift themselves above the surface, the characteristic type being a
rosette of small leaves closely appressed to the ground with a
central sessile inflorescence. Judging from the fact that many of
the species are found in the most widely separated parts of the
country, there must be very few local species ; and the circum-
stances indicate that the distribution marks the remains of a pro-
bably much richer flora.

* Carlyle, Sartor Resartus.

[ 62 ]

Hbbrese to the fIDembere of tbe Batb
fIDicroecopical Societij*

By the Rev. E. T. Stubbs, President.

AFTER a few prelirninary remarks, Mr. Stubbs said .• —
" The first object that we have in belonging to a Micro-
scopical Society is work — actual work. It is not to bring
people together for the sake or showing them marvellous sights,
and things they have never seen or dreamed of before ; it is not
that they should open their mouths in stupid amazement, or that we
should fill them wfth ignorant wonder, and thus gather to ourselves
a few moments of empty, unreasoning applause. But it is for the
sake of work ; for the sake of seeing more ourselves ; and there-
fore of learning how little we really know as we advance in the
study of those works of nature in the animal, vegetable, or mineral
world, of which so small a part is really known.

There is an enormous untrodden field lying open for fresh
explorers and for new discoveries, and we may render our humble
aid in the work.

Just consider for how brief a period the microscope has for any
purpose of real and accurate research been in the hands of man.

It is, I believe, to Roger Bacon, who flourished in the 13th
century, that mankind is indebted to the first conception of the
microscope. Roger Bacon was one of the most eminent men
which England has ever produced ; he was a native of Somerset,
and was born at Ilchester in 12 14. This is a quotation from one
of his works :— ' We can give such figures to transparent bodies,
and disperse them in such order respecting the eye and the
objects, that the rays shall be refracted and bent towards any
place we please. And thus from an incredible distance we may
read the smallest letter, and may mark the smallest particles of
dust and sand, by reason of the greatness of the angle under
which we may see them.' Roger Bacon was accounted a necro-
mancer because when at Oxford he showed people things that
were out of sight ; and we are told that during his life he spent a
considerable sum in experiments amounting to ^2,000 ; i.e.^
;£i8,733 present value.

ADDRESS TO THE BATH MICRO. SOC. 63

' But there is no record of any definite step having been taken
in the direction of making microscopes until the year 1618, when
Cornelius Drebbel, of Alkmaar, in Holland, is said to have
invented the microscope. '■''

But the instrument as described in the works of that and suc-
ceeding times was cumbrous, ill provided with illumination,
difficult of manipulation, and with mechanism so coarse and so
imperfect, and the methods of examination so few and ill-arranged,
that very little progress could be made until the beginning of this
century. However, within the last fifty years, the mechanism of
the microscope has been gradually improved in every direction :
in the penetrating power of the lenses ; in the employment of
special glass, with high refracting index ; in the consequent increase
of the visual angle ; in the mechanism of the tube ; in sub-stage
illumination ; in stage motion ; and in many other particulars.
The instrument in our hands to-day is very different from what it
was fifty years ago, and if our ancestors in microscopical investi-
gation did good work then, how much more easy must it not be
for us to work now, who have the way made so smooth and easy
before us !

And although I am well aware that progress in microscopical
knowledge depends much more upon the o[)erator than upon his
instrument, still we must recognise the fact that the present
improvements in our microscopes are a very great help to the
faithful and zealous worker.

But, no matter of what sort or excellence may be the instru-
ment a man has, it will be of no avail — nothing will avail— if he
has not hsid practice and facility iji mafiipulation. Whatever may
be the instrument a man has, he ought to know it thoroughly and
to be able to use its powers to the utmost.

A friend, an old General Officer, himself an ardent microsco-
pist, told me the following story : — A lady he knew had attained
to great eminence in Natural History and especially in microsco-
pic research. Her work was particularly in Marine Natural
History. She had permission to put several letters after her name,
as Fellow, or Associate, or Corresponding Member, or Honorary

* Is not Mr, Stubbs in error here ? We believe that Drebbel only copied
and sold Janssen's instruments. See Brewster, Quekett, etc. — {Ed.'\

64 ADDRESS TO THE MEMBERS OF THE

Member of several learned societies. She was the wife of a
captain in the merchant service, and thus had special opportuni-
ties for prosecuting her studies and furthering her research ; and
as she had no family, she was in the habit of accompanying her
husband on his various voyages. My friend asked to see the
microscope by means of which she had made so many discoveries,
investigated so many secrets of nature, and gathered to herself so
many honours ; and he told me he would not give five shillings
for the entire instrument ! Some of the parts were held together
by thread, india-rubber bands, twisted wire, and so forth ! Yet
with such a poor microscope she had been able to observe and to
add to the stores of knowledge in such a way as to deserve all
those honours I have mentioned. This shows how necessary is
constant practice, perfect familiarity with your instrument, steady
perseverance, as well as single mindedness in your work.

In all investigations it is of great importance to ascertain, in
some degree at least, what is the order of nature. For then we
may know to a certain extent where impossibilities lie ; where the
way of further advance is really barred against research ; so that
no time may be wasted in that direction. Just as the searcher
after coal will not waste his time in boring through those rocks
which experience or a knowledge of geology tells him never overlie
the carboniferous strata, so a knowledge of the order of nature will
tell you in what localities the gnat may be found ; and in what
waters Plumatella^ Me/kerta, Step/ianoceros, Lophopiis, or Floscu-
laria may abound. And a knowledge of the order of nature will
enable us to see that the means we employ are adequate ; or at
least not opposed to attain the end in view ; and also to show the
easiest, simplest, shortest, most efficient method to reach that end.

But there is a vast field of investigation almost untrodden
lying open before us. And it seems to me that there are several
directions in which investigations may be made with advantage,
and new facts brought to light. Now I am speaking only of what
is easy and within the reach of any earnest worker.

For instance, the whole question of polarised light is very
imperfectly known, and no very real profit has as yet been derived
from its study. Is it not the case that tourmaline, and, I believe,
all polarising substances, are more or less electric ? Now, if it is

BATH MICROSCOPICAL SOCIETY. 65

also^ true, as we have lately learned, that electricity and ether are
only terms for the same thing, may not a deeper study of
polarising substances account for this strange property ? I saw a
photograph of a flash of lightning, ribbon shaped ; was this because
the light was made to vibrate in one plane ? If so, that light was
polarised !

How little is known about the structure and uses of the
antennae ! Kirby and Spence, which we have in our library, will
give us valuable information. Sir John Lubbock, in No. Ixv.,
International Scientific Series, and Linnean Transactions, 1862,
Vol. xxii., p. 283, treats on the subject, and a very interesting paper
was given to this Society some years ago on this matter, but after
all much more remains to be known. Just think of the variety in
shape of antennae : the leafy-branched antennae of Melolo7itha vul-
garis^ the common cockchafer, seven-branched in the male, six in
the female ; all the family of the Lamellicornes : the oak egger
moth, Lasciocampus qiiercus, with its branched antennae; the
plumose antennae of Liparis dispar ; or of the emperor moth,
Sahiniia carpini ; the incrassated antennae of Sphinx iigustri ; and
the immensely long antennae of Adila frischella^ eight times longer
than the body, with 197 joints, each joint equal to the other, and
having two hooks curved and placed on the eleventh and twelfth
joints. Of course, we are all familiar with the swelled joint on
one of the antennae in the Cyclops qiiadricornis ; the hook in the
antenna of the male of Lipeurus baculus, the pigeon louse, is also
noticeable.

Again, in the microscopic world of Rotifera there is much
that remains to be done. That splendid work on Rotifera, by
Hudson and Gosse, the last and best on the subject, will give
great help. Prichard on Infusoria we ought not of course to
neglect ; it is in our library. Only let us bear in mind that he
wrote when it was thought that all Rotifera (or as then called
Rotatoria) were produced by infusions, which is very far from
being the case.

And I cannot too strongly recommend those whose holiday
may lead them to the seashore, to study on the spot the beauties
there spread out before them. Strange it is how very delicate are
those microscopic forms which are found in abundance on the
International Journal of Microscopy and Natural Science.

Third Series. Vol. V. f

66 BATH MICROSCOPICAL SOCIETY.

most exposed coasts, lashed by the fiercest waves in the rocky
pools left by the sea water. To know anything of their life and
beauty one must study them on the spot, if you wish to see them
alive, remembering that of all fluids sea water corrupts the soonest
and becomes unfit to sustain marine life. But every stream and
every pond will yield materials for abundance of study to him
who keeps his eyes open to these things.

Here we have the Kennet and Avon Canal,"where most of the
species of Rotifera and Entomoslraca may be found in abund-
ance, as well as various kinds of water plants, Potomagetons, etc.
It needs some experience in the search, and some knowledge of
the localities, to discover these treasures, but it is well worth the
trouble. With such advantages before them the members of the
Bath Microscopical Society may well be expected to do something
in the way of investigation.

Absorption of Organic Matter by Plants. — In a commu-
nication from Prof Calderon, of the Institute of Las Palmas,
Canary Islands, he contests the ordinary view that the nitrogen of
the tissues of plants is derived entirely from the nitrates and
ammoniacal salts absorbed through the roots. He does not, how-
ever, adopt the old theory that the source is the free nitrogen of
the atmosphere, but rather the nitrogenous organic matter which
is always floating in the air. The nitrogen of plants he divides
into three classes : — Necrophagus. the absorption of dead organic
matter in various stages of decomposition ; plasnwphagus, the
assimilation of living organic matter without elimination or dis-
tinction of any kind, between useful and useless substances, such
as the nutrition of parasites ; and biophagus, the absorption of
living organisms, such as that known in the case of insectivorous
plants. A further illustration of the latter kind of nutrition is,
according to Prof Calderon, furnished by all plants provided with
viscid hairs or a glutinous excretion, the object of which is the
detention and destruction of small insects. To prove the import-
ance of the nitrogenous substances floating in the air to the life of
plants, he deprived air of all organic matter in the mode described
by Prof Tyndall, and subjected lichens to the access only of this
filtered air and distilled water, when he found all these physiologi-
cal functions to be suddenly suspended — Nature.

[ 67 ]

Bacteria of tbc Sputa anb Crvptogamic
Iflora of tbe flDoutb.

By Filandro Vicentini, M.D., Chieti, Italy.

SECOND MEMOIR.
Translated by Professor E. Saieghi.

IRecent Bacrerlolocjlcal IResearcbes on tbe Sputa ;
tbe /IIborpbo(og>? an& Biology Q)X tbe /IDtctobes
<^t tbe /Iboutb*

Further Remarks on the Bacteria and Bacilli found

IN the Sputa,

and their relation to the " Leptothrix buccalis ;^' the result of
original observations on the morphology and biology of this
parasite, principally on its higher phases, now for the first
time examined and described.

( Conthiuation of the Memoir on the Sputa of Whooping- Cough, Vol. XL! 11.^
of the " Atti Accademicia," Medico- Chirurgica di Napoli. )

" The manner of reproduction and the reproductive bodies of the Leptothrix
are not known ; but, perhaps, more accurate research will discover them :
this hypothesis being based on the fact that, in the interior of filaments
magnified to 800 diameters, small, round bodies are seen which might be
spores." — Robin.

Summary :

§ I. — Further remarks on bacteria and bacilli found in the sputa
and contents of the mouth — A resume of the preceding
work — Some forms of bacteria not therein described — Other
forms of bacilli, ut supra.

§ 2. — Summary of the present investigations and methods of tech-
nique— Collecting and preparing the sputa and the buccal
contents.

§ 3. — Previous opinions on the micro-organisms of the buccal
cavity, according to Miller— History and general facts —
Leptothrix buccalis (Leptothrix ifinominata, M.) — Other
buccal micro-organisms — Buccal pathogenic fungi.

68 BACTERIA IN THE SPUTA

§ 4.— Observations on the morphology and biology of Leptothrix
buccalis — The four phases of Leptothrix^ particularly the fruc-
tification by spores — Production by /^/;^/^ (male organs, ?)
— Fructification of spores reproduced in the sputa — Dissemi-
nation of microbes in the posterior organs.

Recapitulation. — Bibliography.

§ I.

FURTHER REMARKS ON THE BACTERIA AND BACILLI

FOUND IN THE SPUTA AND IN THE CONTENTS

OF THE MOUTH.

AT the meeting of 25th November, 1888, I had the honour of
presenting to this illustrious Academy a memoir on the
sputa of Pertussis, in which I incidentally touched upon
sputa of another character.

It is not my intention to re-open all the questions before treated,
but simply to refer to the bacteriological aspects. The recent
observations refer to all bacteria and bacilli found in normal sputa
as well as in those of various morbid conditions, the so-called
tubercular bacilli not excluded, it being understood that the
many special questions belonging to the latter bacilli will be
fully considered later on.

Confining my remarks to the bacteriological researches in
sputa, I will briefly repeat the conclusions I came to in the
preceding memoir : — " The bacteria generally found in the sputa,
and particularly in those of Pertussis, or Whooping-Cough, are
derived, in all probability, from germs originating in the mouth
and nose, so that (and until irrefutable proof to the contrary) their
presence is to be taken as a natural fact, which has nothing to do
with the cause of the disease. Such bacteria, although of very
varied forms, can be reduced to two sole types, representing as many
phases or forms of transition. One group may be identified with
Bacteriwn termo and the other with Leptothrix; and probably even
these two groups belong to a single species."

And elsewhere : — " In summing up the feature of the different
types, we may conclude that the many forms of Bacteria delineated

AND CONTENTS OF THE MOUTH. 69

in our plate, together with the others simply pointed out in the
text, can be reduced to two species, viz. : Bacterium termo and
Leptothrix.

The forms a, b c, above (Fig. 2, PI. VII.*), d, e,f,f\ g, z, k, /, /,
/, and p\ apply to Bacterium termo ; the forms b\ c (below), m^ «,
n\ 0 (left), ^, /', i", z/, v^ v\ X, x\ y, and z, to Leptothrix. And it is
not improbable that, in their turn, the two species, according to
Cohn, Naegeli, De Bary, and others, may form only one. These
authors classified the round Bacterium {rnonas crepusculum), Bacte-
rium termo and Leptothrix^ as three forms or developments of one
and the same species.

I am rather inclined to believe that even the forms known
under the names of Vibrio rugula, clostrium^ and rhabdomonas may
be attributed to the same species, as three simple varieties of its
bacillary forms." I base these conclusions upon indirect signs,
and especially upon certain morphological characters, common or
transitional, on the usual habitat, etc.

Now, having followed up this line of research for the last two
years, I think I may be able to give a direct demonstration of my
work, by indicating, so to speak, the explanation of the polymor-
phism of the various microbes lodged in the sputa.

Moreover, in the preceding paper, several types of Bacteria
and Bacilli, for brevity's sake, were overlooked, as well as other
specimens drawn from further observations, f

* This plate appeared in the April (1894) part of Journal^ and Figs, 4 to
16 will be found on Plate VI. of the present part.

t Whilst again touching on Whooping-cough, and in continuation of our
bibliographical notices, we may mention a late article from Mircoli on " Renal
Alterations in Pertussis" [Arch. p. le Sc. Alediche, 1890, p. 63, etc.) Mircoli
inoculated, ineffectually, the cultures of bacteria, taken from the larynx of
children who had died from Whooping-cough, into the larynx or under the skin
of rabbits. He mentions articles from Sseurtschenho and Wendt, confirming
the observations of Afanasieff. In the Journal of Microscopy ajid Naiuj-al
Science, edited by Alfred Allen (January, 1890), there is a Lecture given by
Dr. Shingleton Smith before the Microscopical Society of Bristol ( "On Some
Recent Developments of the doctrine of a Contagium Vivum "), where (at p.
32) it is said that the efficacy of special micro-organisms in most of the con-
tagious diseases, and particularly in those most common to children, as
Measles, Whooping-cough, and Scarlet fever, is not proved.

"70 BACTERIA IN THE SPUTA

Some forms of Bacteria not described in the preceding

Memoir (Fig. 4).

All forms of Bacteria and Bacilli herein described (Figs. 4 and
5) are coloured with gentian violet, excluding the filament or ser-
pentine bacillus, h' (Fig. 5), which has been stained with iodine
solution.

{a) In the preceding Memoir I maintained that the typical
curved Diplococci— ^, /, p (Fig. 2) — which are morphologically
identical with the Gonococci of Neisser, never present a capsular
appearance, and this proves to be so in most cases. But from
further observations I have found exceptions to this rule, as is
shown in Fig. 4^ (magnified to 690 diameters). Here, in fact, the
curved Diplococci are intermixed with straight Bacteria, on parallel
cross lines, and are enclosed with the same envelope, which con-
tains the whole. I found on December, 1890, similar specimens
for the first time in the thick, opaque sputa of a child of seventeen
months affected with Whooping-cough, and on the seventh day after
the expectoration. The sputa contained, in the midst of common
bacteria and bacilli, a fair number of red blood-corpuscles with a
few ellipsoidal epithelia and granules of myelin. But, later on, I
accidentally met with similar specimens in urine. This is no cause
for surprise, as I believe that the impregnation of microbes in the
urinary and spermatic passages to be the same as that of microbes
vegetating in sputa, as they proceed from the same parasite, Lep-
tothrix, which vegetates both in the mouth and in the external
genito-urinary passages, as I shall prove later on.

In the third section I hope to show likewise the analogy between
this type of Bacterium and \hQ Jodococcus vaginatus of Miller.

But, besides these curved diplococci, which are intermixed with
straight bacteria in a common envelope, others are to be found
coupled only and enclosed in one sheath by pairs (seldom) in the
patina dentaria (white deposit upon the teeth) around the rich
colonies of Diplococci. Their capsular appearance is made
striking, owing to the staining with picric acid and successive
saturation in glycerine.

^,b\ — This specimen (magnified to 1750 diameters) is taken
from the patina dentaria^ mixed with saliva ; groups of diplococci
are seen in it, both large and of medium size, interwoven with

AND CONTENTS OF THE MOUTH. 71

Strings of very minute cocci, morphologically identical with those
of type s (Fig. 2).

Such specimens, as well as diplococci with the capsular appear-
ance of type / (same figure), reproduced in d' (Fig. 4), are num-
berless. These diplococci are of two sizes, large or medium of
type / (Fig. 2) and others, surrounded likewise by a clear sheath,
but small, as in d' (Fig. 4, right). The small cocci enclosed in If' do
not differ materially from those of the beaded forms (with the
exception of being surrounded by a sheath). I have observed that
these minute diplococci are the heavier, because they are found
mostly on the slide, whilst the large diplococci adhere to the
cover-glass.

Now, the specimen drawn in I? shows that the beaded forms,
morphologically identical with the bacilli of Koch, are found in
the patina dentaria, as well as in the solid and stagnant substrata,
viz., within the buccal epithelia or in the morbid secretions, either
in the crypts of the larynx or the tubercular products, in so far as
the inactivity of the part favours the multiplication of the lineal
series of cocci, which first form strings of beads and then small
rods or filaments, as I have already demonstrated.

In the second place, from this specimen, I believe there exists
a close affinity between those beads and diplococci, either of the
buccal cavity or of some other habitat ; otherwise I cannot under-
stand why they should be so close together as to resemble fru^s
fallen from the same tree.

Another example of the tendency those minute cocci have to
adhere to the diplococci is seen in /.

{c) The couples of dumb-bell bacteria herein shown (magnified
to 2,500 diameters) are taken from the nasal mucus in its normal
condition. I contend that they do not differ at all from the ordi-
nary dumb-bell and chain-like bacteria found in the sputa upon
the types c, d, e (Fig. 2), which remind us of the form and size of
Bacterium termo.

On examining thick nasal mucus, I met with myriads of such
bacteria. In this case the material to be examined must be taken
from the dry cavities of the nose by a glass rod.

We shall see that those dumb-bell bacteria are more apt to form
chains ; in fact, they constitute the remarkable groups or bundles
of chain-like bacteria found on the surface of the tongue.

72

BACTERIA IN THE SPUTA

According to my researches, each dumb-bell is the result of
two cocci linked together by their heads. For this reason, it is
often found, enclosed by a sheath, either inside or outside of the
epitheha of the mouth, nose, or urethra. It is this adhesive ten-
dency which forms them into chains or groups, from which in less
moist parts will germinate the growth of Leptothrix, as we shall
see later on.

I must refer to the preceding Memoir for the other forms of
bacilli and bacteria, all related to Leptothrix. With regard to the
nasal mucus, its pavement epithelia are smaller than the same epi-
thelia of the mouth and less softened, perhaps from not being
under the dissolving action of the saliva.

The bacteria which invade the pavement epithelia of the
urethral mucus, taken directly from the meatus, often resemble
dumb-bell forms. However, in the blenorrhcegic flow, are often
found rather small diplococci, some in the pavement epithelia and
others within pus corpuscles ; but curved diplococci or gonococci
of Neisser are rarely found in it. Beside these common forms, I
also detected very minute cocci, like those rosaries of type s (Fig.
2) or ^ (Fig. 4), and filaments or short articulations of Leptothrix.

d, e. — I have said before that the features of pneumococci of
Friedlander, or Frankel, etc., were probably derived from a
degree of colouration of some points of their single articulations
9r from modifications of forms, as types d and e will show.

In d (Fig. 4, magnified to 2,500 diameters) are seen three
sheathed diplococci, with sheath partially coloured.

In certain cases of pneumonia, we found some specimens of
these, intermixed in the same group or colony.

In e the diplococci have no sheath and show points of varied
partial colouring. Such specimens were obtained from a pulmon-
ary sputa, in which, amongst other forms of bacilli and bacteria,
were pneumococci of types _,/^ g^ h, /, i'.

ft f\ E- — These are specimens of the second kind, taken from
the same sputum in a case of croupal pneumonia. In / (magni-
fied to 1,750 diameters) the capsular appearances are so well
surrounded as to resemble a capsular membrane. The single
pneumococci are sometimes in groups of eight, ten, and fourteen.
The internal articulations are prolonged and end in points.

AND CONTENTS OF THE MOUTH. 73

In/' (magnified to the same degree) the articulations are also
acuminated, but have no halo, and at first are very pale. In suc-
cessive days they become partially coloured in the preparation if
kept artificially moist. These pale Diplococci, without sheath,
appeared to be in a state of active germination, as we detected
therein the more minute and proportionally paler forms, some
being composed of unequal cocci, and several were moving about
in the medium. The forms surrounded by sheath are firmer or
less active, as if the capsule indicated the quiescent state of the
microbe. In fact, if it moves, it is by a motion of simple transla-
tion, without vibrating, as is the case with bacteria in active
germination. ""'

It appears that the capsule, owing to its great refraction, and
also to the difficulty the near small bodies find in crossing it,
resembles a fatty substance surrounding the microbe or proceed-
ing from it. This is only an hypothesis.

In ^ (magnified to 2,500 diameters) is shown a distinct diplo-
coccus, but with the internal articulations nearly cylindrical, with a
large and somewhat irregular capsule, resembling the mono-articu-
lated bacillus of type q (Fig. 2). The sheath indicates, even here,
a quiescent state of the microbe and the successive secretion of
pale substance. Some analogy may be found in it to the Bacillus
crassus sputigenus of Kreibhom. (See section 3.)

h. — Intermixed with the diplococci e and /' we find, at times,
in the pulmonitic sputum, these forms without a sheath (magnified
to 2,500 diameters). In one of these forms we infer the process
of increase by seeing the pointed articulation at the right part as
pale as in /'. The lengthened part of the mono-articulated
bacillus is strongly coloured, and, in a good light, exhibits internal
punctuations of deeper colour, especially near the edges : a remark-
able circumstance that makes them resemble the Leptothrix, in
which are also these punctuations or future gemmules.

The above forms are met with in the second period of pul-
monary affections after the fever has subsided, but may also be

* In a recent work, Billet states he has met in other species with this form
of incapsulated diplococci, and considers it a phase of life common to various
species of bacteria. He calls it the zoogloeic state. (This will be again
referred to in a note at the end of Section 3. )

74 BACTERIA IN THE SPUTA

found in successive periods. These pneumococci retain tena-
ciously the gentian violet, as I stated in the first memoir.

Several of the preceding forms of pneumococci, particularly
those of types d^ e, /, /', and h, are analagous with those drawn by
Cornil and Babes in Les Bacteries et leur role^ PI. XV., Figs, i, 4,
6, and 13.*

/, /. — The large round diplococcus, / (magnified to 2,500
diameters), was also found in the second period of a pulmonary
affection. Its articulations resemble two detached hemispheres,
and round the envelope adhere very minute cocci, not one of them
being able to penetrate the clear zone. This fact clearly indicates
the solidity of the sheath.

In i' there is a small chain-like bacterium, the articulations of
which exhibit a series of similar diplococci, so connected that the
hemisphere of the one adheres to that of the other, leaving a
clear space between the hemispheres of each diplococcus. Such
chain-like bacteria are sometimes found grouped together, although
in small number, in pneumonic sputa.

Other Forms of Bacilli, ut supra (Fig. 5).

Some forms of bacilli were omitted in the other memoir for
want of space ; others were collectcfd later on, and these I will
now briefly describe. The new forms added to the first will better
show the identity of the bacilli of the sputa with the articulations
or fragments of the filaments of Leptothrix vegetating in the mouth.

In the preceding Memoir the bacillus n (Fig. 2) represented a
form of transition from the young bacillary forms, «, ?z, n^ to the
mature forms, m, m. I then pointed out other forms of transition.

a^ l)^ c. — In a (Fig. 5, magnified to 1,250 diameters) is seen a
bacillus that partakes of three distinct types, divided into three
segments : one internally occupied by four ellipsoidal bacteria, the
clear segment in the middle, slightly coloured, and the other
deeply coloured and opaque. It shows that the clear bacilli
inside — those containing bacteria and those entirely opaque —
belong to the same species. This bacillus was taken from influ-
enza sputum, but similar forms were found in other sputa and in

the saliva.

* Work quoted in the Bibliographical Appendix.

AND CONTENTS OF THE MOUTH. 75

Another analogical proof we have in b^ where a bacillus, opaque
for five-sixths of its length, exhibits the other one-sixth clear and
slightly coloured. This specimen was taken from the saliva.

In c we find four types — viz. : a short, clear segment above,
and on the top of it a bacterium of elliptical form ; in the middle,
a long, opaque segment ; and in the lower part a pale, granular
segment like the middle feature of type n' (Fig. 2) and types e and
/ (Fig. 5). This specimen was also taken from the saliva.

d. — This short but large bacillus, taken from the patina den-
taria (magnified to 2,500 diameters), exhibits the upper part
opaque and deeply coloured ; the other part is divided into two
segments. The middle segment is very short, clear, and contains
a dumb-bell bacterium placed across ; the lower one is opaque,
but not entirely, as there is on the right a clear space between the
opaque part and the outline, and presents a kind of indentation.
Other bacilli have the same features towards the edges, or near the
junctions of their segments.

As regards the enclosed bacterium, there is no doubt about its
position in the envelope of the bacillus, from the look of the spe-
cimen as well as from the oscillation of the preparation, in which
the bacterium was seen to be always inside. In the preceding
specimens we have also abundant proof of this fact.

Now in the first place, it shows that not only elliptical, very
minute, and linear bacteria, but also dicmb-bell bacteria, may be
found in the envelope of the bacilli ; from which we conclude
there is no difference between the dumb-bell bacteria and the
bacilli. And since the small chains, and the bundles especially,
adhering to the tongue, are mostly formed of dumb-bell bacteria,
we must infer the analogy of those forms with the baciUi, and
consequently of both to the Leptothrix.

In the second place, comparing the various specimens of bacilli
(as a and d), containing bacteria with the fertile filaments of Lep-
tothrix, we find in the latter a variable disposition of internal
granules, or buds, adhesive to the envelope. Some are alternate ;
others on the same level at both sides. If we imagine that in
those filaments the buds grow up towards the middle line of the
stem, It will result that, when the left bud is placed higher than
that on the right, the bacteria resulting from their increase will

76 BACTERIA IN THE SPUTA

range themselves in a longitudinal line, taking the elliptical form,
as in bacillus a. On the contrary, if the two buds are on the same
level, we shall have the case of bacillus d — viz., the two cocci,
resulting from the increase of the buds, will meet in the centre of
the stem, and, there joining together, will produce, in a cross line,
the dumb-bell bacterium.

Therefore, wherever we turn our eyes, the notion of the poly-
morphism of the microbes, and their probable derivation from a
single species, is gaining firmer ground.

<?, e' . — The bacillus drawn in e (Fig. 5, magnified to 1,750 diam.)
was found in the sputa of a young woman in labour, w^ho was
affected with bronchitis. It was mixed with other similar granular
bacilli, clear and of the same length, but more slender, as we see
in/. These baciUi, however, are common also in other sputa and
in the contents of the mouth ; they present a pale, granulated
mass, similar to that of baciUi, n (Fig. 2) and c (Fig. 5). They
also show, in various places, buds or internal granules, smaller and
paler than those found in the fertile filaments of Lepiothrix.

In e the ends are pointed, but in / they are round. The larger
of the two is faintly coloured, but exhibits near one of the heads a
clear interstice, as is seen in a and d. The other specimen,
smaller and paler, exhibits a younger form of the same type.
These two last bacilli were found in pulmonitic sputa, and were
also found in the contents of the mouth.

In the uncoloured preparations of the patina dentaria there are
nail-shaped bacilli, like the type e^ soft, flexible, slightly veined,
and having quick motion (Fig. 14, d). These bacilli are originally
lodged on some pointed productions, as was observed by me for
the first time ; their slender points form the baciUi/ h^ and h' .

/, g, h, h'. — The very slender bacilli, / and g (magnified to
2.500 diameters) are also taken from a case of pneumonia. In
/ we see a mono-articulated and strongly coloured bacillus, as well
as another pale and granulated. In g, a very slender one, the
ends of which appear to have been recently detached from a
longer filament.

By comparing these specimens with the Lepiothrix, no import-
ant difference is noticed.

In h another specimen of curved bacillus, resembling a point

xVND CONTENTS OF THE MOUTH. 77

of interrogation, taken from pulmonitic sputum. These bacilli are
not uncommon in the pati?ta den/aria. They have quick vital
movements. They resemble the Spirillu77i sputigenum of Miller,
or the Comma bacillus of the saliva described by Lewis, as
identical with the cholera bacillus of Koch, Bacillus virgolar

I have, however, found that, between these bacilli and the
lesser points, which are abundant on certain filaments of Lep-
tothrix, there exists a great similarity. These points vary in size,
but all possess quick movements (Fig. 14). We shall consider
later on if these bacilli act like the reproductory filaments (sper-
matia or antherozoids) of many cryptogams, although in Leptothrix
they are not originally contained in special receptacles (spermo-
gones or antherids).

In a more advanced hypothesis, we shall have also to consider
if these bacilli represent the spirilli, or if the spirilli proceed from
such filaments, endowed with the same motile power. It appears
more probable that the spirilli may generally be derived from the
fragments of certain curved filaments, fertile or not, of Leptothrix.
Sometimes the spirillum is thicker than the filaments of Leptothrix^
as in Fig. i of Cornil and Babes. t

In // is seen a larger filament (stained with iodine), found in
\ht pati7ia de?itaria, which is somewhat similar to spermatozoa.

In the uncoloured preparations I have seen the very rapid
movements of all these bacilli. In conclusion, all these forms of
bacilli are common in the expectorations and contents of the
mouth.

§ 11.
SUMMARY OF THE PRESENT INVESTIGATIONS AND

METHODS OF WORKING.

Argument.
In the fourth section of my Memoir on Whooping-cough, I
stated that bacteriological researches on the sputa would be fruit-

* Lewis, A Memorandum on the Comjna-shaped Bacillus^ etc,

t Cornil and Babes, op. cit. — Vicentini, "Sopra un caso di febbre ricorrente
ecc. e sul riscontro degli Spirilli nel Sangue," Atti del. R. Accad. Med. Chir.
di Napoli, 1883, t. xxxvi.

78 BACTERIA IN THE SPUTA

less until the natural history of the pathogenic or non-pathogenic
microbes that lodge there is thoroughly known.

In most cases a complete organism grows in length, breadth,
and thickness. But the chain-like bacteria and the filaments only
grow in one direction (in length) simply by a repetition of particles
in a lineal series. We must, therefore, suppose that neither these
original particles, nor the chaifi-like bacteria and filaments resulting
from them, are complete organisms, but that they are rather rudi-
ments of more perfect ones.

By examining all the different forms of bacteria and bacilli, we
were led to believe in a single type, to which all other forms were
related. Now, we will show that the existence of this vegetation
is to be found in the patina dentaria, in certain sputa, and in the
mucus of the urethra, all the forms hitherto described being only
fragments of it.

If somebody, for instance, not knowing all the phanerogams,
should enter a wood-house, looking at the wood, heaps of branches,
leaves, etc., he might at first suppose that they were different
things instead of parts of a whole. Likewise, if he should see a
threshing-floor upon which is spread and beaten Indian corn, he
might take the stems, roots, leaves, tufts, and grains for as many
different objects. But it will be sufficient to take him out into
the field, to convince him of his mistake. Looking through
the lines of the corn, he would see that most of the plants (the
female ones) are provided with ears, and he would see also others
higher than the rest (the male ones), having instead of ears only,
a tuft.

Then he might suppose that the plants of this second type
were, perhaps, of different kind from the others, not thinking that
Indian corn is a dioecious plant, with distinct sexes on different
individuals.

This is precisely the case with the microbes of sputa. We
were led to the study of the morphology and biology of Leptothrix,
by considering that nothing is useless in nature ; those parts which
now appear superfluous to us in living organisms, (as the nipples
in man) are rare exceptions.

The illustrations of Leptothrix contradict this law. Look, for
instance, in Bizzozero, the figure of Leptothrix buccalis, reproduced

AND CONTENTS OF THE MOUTH. 79

in our Fig. 6, and the query will be asked : — Of what use are those
upright, barren shoots resembling grass, which have been eaten
close by cattle ? This want of fruits cannot be accounted for by
mechanical injuries. The figures of Robin, Frey, Miller, and
others do not suggest a different conclusion.*

After these reflections, we were induced to investigate this
parasite. Our researches will be particularly demonstrated in
Section 4, only a synthesis of them being given here.

From our observations Leptothrix buccalis would, therefore,
live under four forms, or have four different stages of development,
according to the conditions of the alimentary substratum.

In the liquid secretions, as saliva and mucus, its spores -bac-
teria and cocci — and its gemmiferous sprouts — real bacilli (exclud-
ing the Spirilla, the 7iail-like^ the snake-like^ and the comma) —
increase and multiply like moving spores and germs of fungi.
This would be the immersed vegetatioji of Leptothrix.

The bacteria, the yeasts, and the spores have generally the
power of reproducing the full organism like the seeds of the
phanerogams ; but, between the spores of the bacteria on one
side, and the seeds of the phanerogams on the other^ there is this
difference : that those seeds cannot multiply by division, produc-
ing fresh seeds ; whilst moving spores, yeasts, and bacteria multi-
ply abundantly, by fission, even by themselves.

If, however, the liquid is kept quiescent in the crypts or cavi-
ties, or if the part is, as on the surface of the tongue, very firm,
the second period or low vegetation begins, viz., beaded^ chain-like^
and bundle-like bacteria are formed, so common on the patina of
the tongue. But vegetation stops where (as in the mucous parts)
the continual friction impedes a further formation.

In the secretions and mucus there is a relative inactivity; but
if it becomes effective, a reproductive growth will be formed, as
shown in Fig. 16, taken from puhnonitic sputum, which for
several days had adhered in the interior of a closed tube.

The third period, or growth, is when it lodges on a solid part,

* Bizzozero, Manuale cit. nella Bibliografia, PI. II., Fig. 27 ; Robin, His-
toire naiurelledes vegetaux, etc., 1853 (see Bibliography), PI. I., Figs. I and 2.
Frey, figure reproduced by Perroncito, quoted in Bibl., Fig. 1 1. Miller,
figures quoted later on.

80 BACTERIA IN THE SPUTA

on the tongue or teeth. But, owing to the continual friction on
the tongue and teeth, the growth cannot reach the fourth period,
or that of fructification. Then we have bare growths apparently
sterile, as represented above. The same happens with the tufts of
Leptothrix, often found on the epitheUum scales, on the residue of
undigested food, or other corpuscles in urine, sputa, etc., forms
which may be called " aerial," although incomplete, " vegetation."

But in many parts of the dental surface, where there is less
friction, as between tooth and tooth and near the gums, the fourth
phase or fructification takes place. This fact has not been ob-
served, and is not even suspected, as we gather from the most
recent work of Miller. "^'^

I call it aerial vegetation, because the stems of the microphite
have a tendency to rise in the air, although immersed like
the algae. In our case the surrounding liquid is the saliva. This
fructification by spores, first noticed and investigated by me, con-
sists of comparatively long ears (Figs. lo, ii, 12, 13, 16),
formed by the exudation of a viscous substance, faintly coloured,
round the ends of fertile filaments. In this substance are entan-
gled small round spores, often brightly coloured, placed in six
longitudinal lines, as we shall see later. In the strongest speci-
mens (Fig. 16,/, g) as many as 720 spores can be counted in an
ear. All the cocci and minute bacteria are probably dissemina-
tions from these spores.

There is another form of special production, or pseudo-inflo-
rescence, which is drawn in Fig. 14, ^, ^, <:, resembling points^
round a filament or group of fertile filaments. These points
having fallen off form the nail-like, snake-like, or comma bacilli.
If we admit the analogy of these bacilli with the reproductive
filaments of other cryptogams, Leptothrix may be compared to
a fungus, or dioecious alga, with two sexes upon different fila-
ments ; and such pointed productions would exhibit the male
organs, the elements of which, spread about the surrounding
medium, would, with their great mobility, act as antherozoids in a
manner not yet known to us. In such an hypothesis, the
scanty number of such inflorescences, with regard to fructifica-
tion or female organs, would be fully explained. Therefore,

*W. D. Miller, Die Mikro-Organisnien der Mundhohle, etc., 1889.

AND CONTENTS OF THE MOQTH. 81

in summing up the morphological and biological series of
Leptothrix^ beginning with the forms of Cocci or Bacteria, we
pass through the chains, the growths, and end in the fructification
by spores, in order to begin again another series usque ad infini-
tum. But, beside this cycle of reproduction, we must notice
another — of buds and internal impregnation (that already foreseen
by Robin), which is seen in the interior of the envelope of old fila-
ments, articulations, and bacilli, and through which, from the
same bacilli, are generated other bacteria, and this owing to the
reserve buds described above. From those bacteria are, in their
turn, reproduced the chains, the tendrils, and their articulations or
bacilli, as we have seen in the former Memoir on the subject of
bacilli b' and n (below) and in «, u (Fig. 2).

Let us consider what a great cause of dissemination this is,
placed at the entrance of the digestive and respiratory organs.
According to our calculations, there would always be found present
in the nose and mouth, taken together, from two hundred to three
hundred trillions of bacteria, or other elements of the microphite,
ready to enter the stomach at the time of deglutition, and to fall
on to the respiratory passages at every breath. In comparison
with that mass, what are the few germs we inhale from the
atmosphere ?

But if, at every breath we inhale, a propelling motion sends
whole swarms of elements or germs of the microphite into the air-
passages, another slower but continuous movement pushes germs
or analogous elements on into the genito-urinary passages
through contiguity, from one epithelium to another, and onwards
along the mucous patina, passing through the urethral orifice,
which Pasteur has compared, in this case, to the Thames Tunnel.''"

We will briefly treat these questions in Section 4, and demon-
strate the identity of Leptothrix preputialis with Leptothrix buccalis.
Now, to enable others who may be willing to repeat and to verify
our observations, we will proceed to describe the modus operandi,

* Schutzenberger Le fermentazioni, ecc. trad., Milano, 1876, p. 204 ; V.
also Vicentini Caso di vegetazione di funghi microscopici nell' Uretra
ecc, Morgagni, April, 1880.

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. g

82 BACTERIA IN THE SPUTA

Collecting and the Preparation of the Sputa.

In the preceding work we dealt with the collecting and the
treatment of sputa, putting off to another occasion the diagnosis
of derivation of the various materials expectorated, in order that
the real sputa might be distinguished from the particles of food ;
the sputa from the saliva or throat, and the mucus flowing from
the nose, being also differentiated. Now is the moment to touch
on this point again, in order to describe improved methods of
preparation and colouring.

The materials to be submitted to microscopic observation
really do not always proceed from the air-passages. In the case
of a boy, 7 years old, affected with Whooping-cough, we remember
having received a portion of food ejected from the stomach, and
thought to be a sputum. This substance was gelatinous in appear-
ance, the colour of tobacco, and contained a large amount of
alimentary residue ; but what surprised us was a very dense
mycelium of conspicuous sprouts after the type drawn in former
plate,'^'Fig.3, d^ interwoven with other slender ones. The fructifica-
tion of these mycelia produced forms identical with small heads
(capitula) or sporangia, delineated in k and k\ very vigorous, upon
as many as five fertile branches, intermixed with similar vigorous
forms of Aspergillus glaucus. This would lead us to suppose that
the deglutition of the relative germs with the sputa, and their
secondary development, is even more easy and vigorous in the
stomach.

In some cases, especially with children, the proper expector-
ation is lost or swallowed ; and when the patient is ^asked to
spit out again, he emits only a httle saliva, mixed with small flakes
of mucus, from the throat and tonsils. These salivary sputa, how-
ever, may be recognised generally on the following day through
the clarification, after remaining undisturbed, with an upper liquid
stratum (more considerable than in crude sputa, or those mixed
with abundant saliva), and a scanty deposit, very rich in buccal
epithelia, and, eventually, alimentary residue. Besides, they are
recognised from being wanting in ellipsoidal epithelia and granules
of myelin.

* See April, 1894.

AND CONTENTS OF THE MOUTH. 83

Another source of error, against which it is difficult to guard,
is the reflux of nasal mucus, through the posterior nares, in the
back of the mouth, and its successive expectoration mixed with
saliva. Naturally, ellipsoidal epithelia and myelin, even in such
sputa, are wanting.

In any case the presence of the myelin and the ellipsoidal
epithelia induces us to regard the sputum as proceeding from the
air-passages. These are two important points when, for instance,
a doubt arises whether a sputum with a rusty appearance proceeds
from the nose or the chest ; as, in our daily researches on sputa,
we never detected ellipsoidal epithelia or myelin in spurious sputa ;
whilst in the genuine expectorations they are very seldom absent,
and when not found in the first, they appear in the second
preparations.

We come now to the manner of collecting the sputa.

The act of spitting is accomplished in two different efforts :
by the first, the genuine sputum, nearly entirely free from saliva,
and that which is required is coughed up ; but soon after by a
second effort, saliva is emitted with the residue of the sputum left
behind. This second sputum (being nearly all saliva) is elimin-
ated. In order to avoid mixing the sputum with saliva, the patient
should not keep it in the mouth too long.

Instead of a spittoon, it is better to use a colourless plate or
saucer, perfectly clean, where the sputa can be kept separate, and
then selected for examination. The sputum should be taken at
the most viscid point with a bent needle or forceps, and raised so
that the saliva and the more fluid part of the mucus with which
it is mixed, may trickle down on the plate. What remains on the
instrument is quite sufficient for successive investigations, as it will
necessarily contain very little saliva. To preserve it, it should at
once be placed in a glass tube, which has previously been cleaned
with sulphuric acid, and washed out with alcohol.

For the coloured preparations we have to modify the directions
given in the preceding work. It is better to keep the solution of
gentian violet separated from the aniline water, so as to prevent
decomposition ; but we must avoid putting the glass rod, still wet
with aniline water, into the colouring solution, and vice versa.
Two different rods must be used. With a small rod put first on

84 BACTERIA IN THE SPUTA

the slide a drop of aniline water, taken from the relative bottle,
and soon after add a colouring solution. For, by placing the
solution first and the aniline water afterwards, we obtain a greater
precipitation of coloured granules in the preparation.

It is necessary that the particle of sputum should be well
immersed in the colouring mixture, so as to have it well coloured
on its under as well as its upper surface ; because, if the particle
is placed on the slide before the solution, the part adhering to the
glass cannot be coloured. The particle of the sputum should not
be larger than i/4th to i/3rd of a grain of millet ; otherwise,
when pressed between the two slips, it will press out from under
the cover-glass, and consequently the best specimens, which are on
the edges, will be lost, or the preparation will prove too thick for
investigating the most delicate parts.

The particle of sputum, taken with a bent needle, should be
immediately put into the colouring mixture, pressed down for a
short time with the needle, then left for two hours under a watch-
glass ; a drop of distilled water may be added to it, if a weaker
colouring be desired ; or, in hot weather, to prevent hardening or
evaporation.

After the required time has passed, take the sputum with a
perfectly clean needle, put it in a watch-glass containing distilled
water, and, by gentle agitation, it will be freed from the granular
deposits. Meanwhile the slide must be well cleansed. Then put
upon it a drop of distilled water, in which the particle is to be
again immersed. By using glycerine we cannot obtain the proper
thinness of the preparation, and many features would appear to be
altered and colourless. Glycerine can ultimately be substituted
by capillarity to preserve the preparation, the upper surface of the
cover-glass, made greasy by the immersion, being washed first with
benzoin and then with water.

In the preceding Memoir, we recommended the spreading and
thinning of the particle of the sputum with needles ; but for our
present investigation it would not be advisable to do so. It was,
perhaps, owing to this that we then lost some details, especially
with regard to the fructifications of Leptothrix. In fact, spreading
with needles must destroy the relations of continuity and contiguity
necessary to preserve intact the said fructifications.

AND CONTENTS OF THE MOUTH. 85

To thin the preparation as much as possible, we must place
upon it the cover-glass, well centred, and let it act by its own
pressure. In this way the mucus becomes thinned, and spreads
slowly without altering materially the elements involved in it.
When the preparation has become partially thinned, press down
lightly and gently with the rod and leave it undisturbed, and so
on until the very slender film of the coloured matter has in every
direction neared the edges of the cover-glass ; care being taken in
these handlings to strain off the redundant liquid without wetting
the upper surface of the cover-glass.

The preparations so mounted, in water, are in all parts very
transparent, clear, and bright ; they do not exhibit superposition
of elements or corpuscles, and even in hot weather, keep well under
the microscope for several days, if care be taken to wet now and
then one of the edges, as we suggested in the first Memoir. Even
the bacteria in the centre of the particle of sputum which were
not at first reached by the colouring medium become in time gra-
dually coloured, and these weak colourings are often very useful
for examining minute details.

In order to obtain fructifications of Leptothrix from sputa, it is
necessary to take the particle of sputum, not from the bottom, but
from that side of the tube where, perhaps accidentally, a vertical
streak of the mucus, slender and adhesive, has been left, as we
shall see later.

For researches on fructifications, powerful immersion objectives
are required, so as to be able to detect all details. We have used
a No. II objective (i/i8th homogeneous immersion) of Hartnack.

Collection and Preparation of the Contents of the Mouth.

We shall especially deal with t\iQ. patina dentaria (surface of the
enamel, tartar), etc., saliva and patina of the tongue.

Patina Dentaria. — The deep layers of this patina contain almost
exclusively bud-growths and knots of large filaments which take a
brilUant colour with the solution of iodine. The fructifications,
on the contrary, are simply found on the superficial layers, so that
for their investigation we must possibly remove the upper surface
of the patina. By scraping the tooth with a small instrument or the

86 BACTERIA IN THE SPUTA

nail, too much tartar is removed, which must be disintegrated
twice over ; first to select a particle, and then to thin and spread
it on the slide I have best succeeded with a bent needle, first
scaling lightly the labial surface of the tooth, and carrying the very
minute particle of the patina on to the slide (on which was placed
a drop of aniline water), and then scraping likewise the interstice
between the teeth, to place on the slide another similar particle.
In order not to spoil the fructifications, the scraping should be
made neatly from top to bottom. This manipulation should be
done in the morning, fasting, and cannot give good results in
those subjects who habitually clean their teeth with tooth-brush
and powders.

Thus we get within the drop of aniline water two tiny islands
of Leptothrix, but they are yet too thick to be reduced to the thin-
ness required. We shall break them with the needles, so as to
carry on to the slide only a kind of whitish dust, which will occupy
a third of the area to be covered. Having done this, we shall add
with the rod another drop of aniline water, and soon after, with
a different rod, a drop of gentian violet solution. We shall speak
of the other colourings in Section 4, the treatment being nearly
the same. The preparation is kept for a little while under a glass,
and when it appears to the naked eye to be sufficiently coloured, it
is mounted without washing, which, in this case, would take away
all the fragments, the fructifications will be set free, and the bacilli
float about each tiny island.

When we wish to examine together the saliva and the patina
dentaria, instead of placing a drop of aniline water previously on
the slide, we will put on it a drop of saliva in the manner we shall
indicate by-and-by ; the rest of the treatment is the same. How-
ever, the preparations without the saliva turn out clearer and
thinner ; whilst those mixed with it cannot become thin enough,
owing to the resistance presented by cumuli of large buccal epi-
thelia, which place themselves like supports between the slides ;
still worse when one of those cumuli happens to be on a bed of
Leptothrix. Naturally, in the preparations mixed with saliva, the
rich cumuli of Diplococci are more abundant, whilst they are
seldom found on those of the patina only.

Lastly, the cover-glass is put on and gently pressed down with

AND CONTENTvS OF THE MOUTH. 87

the rod, until the layer of the Leptothrtx, spreading in every direc-
tion, reaches the edges of the cover, and the redundant liquid
trickles down by its side. The preparations, stained with aniline
colours, become a little hard (perhaps owing to the alcohol in it) ;
but yet they get thinned enough. Those treated with the iodine,
and especially those treated with picric acid, or the colourless ones,
being more flexible, become more easily thinned.

In order to see the fructifications in a fair quantity and dis-
tinctly, it is necessary to wait some time. Naturally, those on the
edges of each tiny island are seen more distinctly, but all do not
show them, because many of the islands contain only filaments or
bud-growths. Some are wasted, and others overlie one another,
mixing their relative edges together. Now, in those edges with
exuberant fructifications, these at first are close together ; but the
preparation in time partially dries up, and on pouring on it a fresh
drop of distilled water the cover-glass slightly rises, and then the
tufts of ears begin to open ; the ears separate one from another,
and (in preparations with picric acid) several may be counted in,
the visual field. Such observations can be continued for several
days by adding to the preparation from time to time a drop of
distilled water.

To demonstrate the productions by points, the method of
working must be modified, as we shall see in Section 4.

Saliva. — To get the saliva as far as possible free from froth
and air-bubbles, the following plan should be adopted : — Let the
patient before tasting food spit on a well cleaned glass rod, held
horizontally ; then incline it so that the saliva shall run down
towards the hand, parting, in its course, from the small air-bubbles,
which, being lighter, adhere to the rod and stop the froth. When
a drop of saliva has gathered on the handle, it may be taken off
by the point of a second rod and carried directly on to the slide
(if we wish to examine it with the patina deiitaria and then mix
them together); or, if we wish to examine them separately, it
should be immersed in a drop of colouring mixture, already placed
on the slide. As soon as the preparation is sufficiently coloured,
it should be covered without washing. If the colouring is very
weak, with slight vestiges of colour, the vibrating motion in the
salivary corpuscles will be better detected.

88 SNOW CRYSTALS.

The Cuticle of the Tongue.— On an empty stomach, the surface
of the tongue is scraped with a spatula or tongue-scraper. We
take a small particle of the product and put it in the aniline water
previously deposited on the slide. Afterwards it is carefully divided
and coloured like the patina dentaria. However, owing to the
superposed epithelia, these preparations can never be properly
thinned, and therefore are only in a few points rendered clear
enough for investigation under high powers.

Snow Cri?6tal9*

By J. H.

IT is almost impossible to imagine the extreme beauty and
variety presented by snow crystals. During a sudden fall of
temperature lasting only a few days in the last winter, very
many intensely beautiful forms of crystals were preserved by the
aid of photomicrography. Very many were made up of prisms of
six facets. Many presented the appearance of being double ; that
is, two crystals alike in form were united to an axis at right angles
to the plane of each. These were generally fine examples of the
less minute crystalline bodies ; the rays proceeding from the under
crystals in most cases filling the intermediate space between those
of the upper, and as crystals of a more complex order, and in
most cases exhibiting a richness of effect hardly to be exaggerated.
It was to me an extremely agreeable study of the various compli-
cated forms presented to the eye, whether observed by a low
power, or seen by the aid of the microscope, in all their beauti-
ful details. A country friend engaged in a similar pursuit
made a series of sketches^ drawn about their natural size, with a
crowquill ; while another presented me with sketches made about
the same time as my own, some of which presented wonderful
details, surpassing any of those I had observed.

A collection of snow crystals, accurately recorded, might, it
appears to me, be made to present an interesting feature in
meteorologcal investigation. At the same time, it is highly pro-
bable that the conditions of their formation are more complex than
might be imagined, familiar as we are with the conditions relating
to the crystallisation of water on the earth's surface.

PLATE VII.

Snow Crystals.

[ 91 ]

apocbroniatic ©bjectivcB for tbe flDicroecope^

MR. J. G. Wright publishes the following paper in iho. Journal
of the Btrmmgha7?i Natural History and Philosophical
Society (Vol. I., 1894, pp. 57 — 61) : —

" A great advance has been made during late years in optical
science as applied to microscopical work, through the laborious
and exhaustive investigations of the subject by Prof. Abbe and
Dr. Schott of Jena. Those gentlemen, after years of patient labour
and study, have discovered new vitreous compounds, by the use of
which, and aided by the celebrated optical workshops of HerrCarl
Zeiss, they have constructed lenses capable of forming images
much more perfect than any hitherto seen, and indeed have lifted
the art of the construction of microscope 'objectives' into an
almost ideal position.

The nature and advantage of these improvements will be
understood from the following considerations and explanations.
The ideal desideratum in a lens or a combination of lenses is to
produce an image of perfect definition, free from all colour inter-
ferences. There are, however, some serious difficulties in the way
of realising it. When rays of light pass through a lens, those
passing through the axial zone are focussed at a point further from
the lens than those passing through the peripheral zone, while those
passing intermediate zones focus themselves at points intermediate
between those two. Hence the image formed by the lens is
imperfect in any one of these focal points. This difficulty is
known as ' spherical aberration.'

When a beam of light passes through a lens, the various
coloured rays are refracted at different angles. Thus, the violet
rays are focussed at a point nearer to the lens than the red rays,
and the intermediate colours at varying points between those two,
so that the image viewed at any one of these foci is more or less
imperfect and blurred. This difficulty is known as ' chromatic
aberration.' Both these difficulties are partially corrected by a
so-called ' achromatic ' arrangement of lenses, in which a bi-convex
lens of crown glass is closely attached to a plano-concave lens of
flint glass, the latter possessing a lower refractive index and a less

92 APOCHROMATIC OBJECTIVES

dispersive power than the former. By this means the spherical
aberration is corrected for otie colour in the brightest part of the
spectrum, and the chromatic aberration is reduced by uniting two
of the colours of the spectrum in one point of the optic axis.
The remaining colours deviate and form what is known as the
* secondary spectrum.' The above-named corrections represent
the highest conditions of achromatism previously attained even in
the very best lenses.

The new German crown and flint glasses, possessing different
relations of dispersing and refracting power, have, in combination
with a lens of fluor spar, made it practicable to destroy the secon-
dary spectrum, or very nearly so, by uniting three of the colours in
one focus, and at the same time to correct the spherical aberration
in two colours.

This higher range of achromatism Prof. Abbe calls ' apochro-
matism.' It was a great advance in microscopic optics, and seems
to leave little room for further progress in the present state of
optical science.

In wide-angled objectives, where, by reason of its shape, the
front lens cannot be made achromatic, there remains still a trifling
colour deviation which interferes with the perfection of the image.
This Prof. Abbe corrects by the construction of what he calls
' compensating ' eyepieces or ' oculars,' in which the under-correc-
tion of the objective is balanced by the over-correction of the eye-
piece, and so a perfect image is obtained. And in order that these
eye-pieces may be used with all his objectives, Zeiss makes them
all under-corrected, so as to be balanced by the compensating
eye-pieces.

Another advantage accrues to these eye-pieces by the new
method of their denomination. The old and almost meaningless
denomination by letters — (A, B, C, D, etc.) — is discontinued, and,
instead, they are designated by numbers — (4, 6, 8, 12, 18, and 27) —
each indicating the initial magnification of the ocular. By this
means the total magnification of the object viewed is most readily
ascertained. It is only necessary to multiply the initial magnifica-
tion of the objective by that of the eye-piece (as ascertained by its
number) to give the combined amplification. The power of the
objective is readily found by dividing the length of the microscope

FOR THE MICROSCOPE.

93

tube (lo in. in the standard English instruments) by the nominal
length of focus of the objective. Thus : a i-inch objective mag-
nifies lo diameters, and if used with a 12 eye-piece the amplifica-
tion is 10X12 = 120 diameters. Similarly, a ^-inch objective
magnifies 40 diameters, and if used with an 18 eye-piece the total
amplification is 40 x 18= 720 diameters.

Another very important advantage in the new system of con-
struction arises from the fact that, whereas in the old achromatic
arrangement the image formed by the lenses was so imperfect that
deep-eye piecing could not be resorted to without almost certainly
breaking down the image ; in the apochromatic combinations
amplification may be accomplished by the use of the deepest
oculars without at all impairing the definition. This enables the
worker to take advantage of the longer working distance, which
the focal length of the lower power objective gives him, and also
secures the greater amplification with less costly apparatus.

The advantages of the apochromatic system may be conven-
iently summarised as follows : —

In the Achrotnatic System.

The sharpness of the image is
limited to 07ie colour of the light
rays — the green-yellow in ordi-
nary lenses; the blue-violet in
lenses for photographic pur-
poses ; the other rays giving
confused images.

Complete colour correction is
effected in one zone only of the
objectives, the peripheral and
central zones showing a marked
imperfection. And only two
colours are united in one focus
in that zone.

In the Apochromatic System.

The images are very nearly
equally sharp for all colours of
the ■•spectrum, and therefore
scarcely affected by the colour
of the illuminating light.

Colour correction is uniform
in all the zones, while thf'ee
colours are united in one focus.
By this means the amount of
focal difference for the various
colours of the spectrum is re-
duced to less than i/8th of its
original amount, which is a
practical elimination of the dif-
ferences.

A considerably increased con-
centration of light, and the re-

94 APOCHROMATIC OBJECTIVES

production of the natural colors

of objects, even of delicate tints,

as well as the ability to use very

high power eye-pieces^ without

breaking down the image, are

advantages which will be keenly

appreciated by the scientific

worker.

All Zeiss's apochromatic objectives are made with relatively

wide angles of aperture. A few years ago the contentions among

microscopists as to the relative merits of high- and low- angled

objectives were very strong, and even fierce ; but later experience

from the extended use of the former has much modified the views

of those whose contentions were in favour of the latter. The

present opinion of the best experts seems to be that for critical

ocula?' work the wide-angled glasses are greatly superior to the low,

while for photographic and some other purposes the low-angled

glasses with their longer focus have an advantage.

Prof. Abbe has made a very necessary and useful reform in the
designation of the aperture of lenses. The aperture is the mea-
sure of the defining power of an objective. The wider the angle
the greater the number of image-forming rays passing into the
objective ; and conversely, the smaller the angle the fewer the rays.
The old term, ' angular aperture ' — which means the angle con-
tained between two lines drawn from the focal point to the oppo-
site sides of the pencil of light emerging from the back lens of any
objective was sufficient to indicate the relative defining power of
objectives, so long as air was the medium through which the object
was viewed. But when ' immersion ' lenses were introduced,
where water or oil became the media in place of air, the differing
refractive powers of these fluids rendered the term inadequate.
Obviously, the refractive index of the medium intervening between
the cover-glass of the object and the front lens of the objective,
must be a factor in the determination of aperture.

These considerations led Prof. Abbe to adopt the term ' Nu-
merical Aperture' (N.A.), and to establish for its determination
the formula, ?t sin. z^=N.A., where n represents the refractive
index of the medium between lens and cover-glass, and sin. u

FOR THE MICROSCOPE. 95

represents the natural sine of half the angle of aperture of the
objective in air. The refractive index of air being taken as i,
water is 1*33, and the kind of oil usually employed is i'52. On
this basis the greatest possible theoretical angle in air — 180° — is
equalled by 97*^ in water and 82^ in oil ; that is to say, as many
rays pass into the objective through oil with an aperture of 82°,
and through water with 97 ''j as can be received through air in a
" dry " objective with an angle of 180°.

The advantage, therefore, of the immersion system is obviously
very great. The highest results which the present condition of
optical science has placed within the reach of the microscopist are
obtained, so far as the present writer is aware, by the use of the
apochromatic system of homogeneous immersion lenses construct-
ed by Carl Zeiss, of Jena, from formulae of Prof. Abbe, and
specially by an objective with an aperture of i'6o N.A , with
which an immersion fluid of higher refractive index than oil is
used. There does not appear to be any scientific bar to the ' con-
struction of objectives of a yet increased aperture. The difficulty
consists in the discovery of a suitable immersion liquid, which
should have an index of i"8 or 1*9 to make any real advance on
present attainments. Glass for the front lens and cover-glasses of
the corresponding index could be made without difficulty so as to
preserve the homogeneity.

Regarding the relative merits of the best German and English
made objectives, the present writer is not aware of any superiority
in any way in the English make, nor of any inferiority. The
German glasses are first-rate in performance and in workmanship
throughout ; whilst in the case of some of the lower powers (half-
inch to quarter-inch) the cost is from j[^2 to £^t^ each less than
their English rivals. The cost in all cases increases rapidly as the
numerical aperture approaches the limits. A one-inch Zeiss'
apochromatic objective with 0*30 N.A. costs ^£6 ; a half-inch of
0*65 N.A., jQ"] ; and the special i/io lens, above referred to, of
I '60 N.A., costs ^40 : while the best English lenses cost ;£io for
a half-inch of 0*64 N.A., and jQ^o for a i/ioth with 1-50 N.A.
These high prices are a secondary consideration where scientific
investigations demand their use ; but they are, without doubt, a
bar to the extensive use of the new lenses among ordinary workers.

[ 96 ]

Zbc Hquanum.

WE have often heard microscopists express a wish to start an
aquarium ; but they always seem to be deterred from doing
so under the erroneous impression that it will entail too
great a tax on their spare time. We have assured them that this
is not the case ; but our remarks have been received with a
TAomas-like belief. We are, therefore, very glad to have
received the permission of the Editor of the British and Colonial
Druggist to reproduce the following article, which has just appeared
in the British and Colonial Druggists^ Diary ^ an extremely elegant
and useful work : —

" There must be many .... who have often desired to
follow some inexpensive ' hobby ' with which to beguile the casual
leisure they may have at their disposal. To those .... we
can recommend the starting of an aquarium as an unfailing source
of amusement and recreation. Those situated in large towns,
even in the heart of the metropolis, need not be debarred from
this pleasure, for all that is needed is one or two visits to a well-
stocked pond to procure an ample supply of material, both animal
and vegetable. For Londoners we know of no happier hunting-
ground than that known as the ' Leg of Mutton Pond ' at the
bottom of the West Heath at Hampstead. From it we have
obtained almost all the animal life mentioned in this paper, includ-
ing many rare species ; most of the plants are also to be procured
in it, or in the ponds in the near neighbourhood.

First, as regards the position of the aquarium. This should
be placed in a good daylight, diffused, but not too strong ; other-
wise, confervse will grow too rapidly. ...

In arranging our stock, we have always preferred the natural
objects that are to be obtained from any pond or stream to the
conventional plants and animals . . . which are, to our mind,
uninteresting and commonplace. One friend [a pharmacist] for
whom we installed an aquarium containing, inter alia, a score or
two of lively tadpoles, had the pleasure of hearing one of his
juvenile customers remark that ' Mr. X had a lot of his pills swim-
ming about in water with tails to 'em/ .... The first point
to be attacked is the bottom soil, in which to grow the plants ; i

THE AQUARIUM. 97

possible, this should consist of a pound or two of mud or clay
from the bottom of a pond. This will probably contain many ova
or larv?e, which will develop in due course into interesting objects.
If this be not procurable, a good layer of silver sand will suffice.
This should be covered to the extent of about an inch with red
gravel, which in its turn should bear a stratum of about half-an-
inch of larger stones and a few empty clean shells. A little tap-
water should then be syphoned on, and the aquarium is ready for
its plants.

Of all plants, none, in our experience, excels the common
American pond-weed, Elodea canadensis (formerly called Anacha-
ris). This plant will grow anywhere with the greatest profusion ;
it need not be rooted ; a few sprigs thrown into the water will
speedily send down roots of their own accord. So luxuriantly does
it flourish, that it will generally require a little judicious pruning to
keep it within bounds. Another excellent plant is Ceratophyllum
submersum, the hornwort. This should he taken with the roots
and planted ; it will then live for years. It frequently has adher-
ing to the leaves the interesting rotifer, Melicerta ringens, and also
sometimes the lovely Stephanoceros eichornii, which, to the owner
of a microscope, will be an unfailing source of pleasure. The
common pond-weed, Potoniageton heterophyllus, the perfoliate pond-
weed, P. pe7'foHatiis^ also P. pectinafus, are useful and attractive
plants. All may be found in the canals round London or in the
country. A root or two of the water crawfoot, R. aquatilis^ will
also grow well, and give a beautiful effect with its finely divided,
fennel-like, submersed leaves. If taken when in flower in the
early . summer, it will continue to bloom for weeks, the elegant
white flowers being as attractive in appearance as those of a rare
exotic. A few plants of one of the duckweeds may be usefully
included ; but too many should not be introduced, as when their
location suits them they increase by budding very fast. The great
duckweed, Lenma polyrhiza, and the ivy-leaved duckweed, Lemna
trisidca^ are preferable to the other species, being neater and not
so prone to decay and leave unsightly withered fronds.

Having introduced the plants, rooting such as have roots, and
placing a few small stones over the soil to prevent them from
dragging their anchors, the aquarium should be placed where it is

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. h

98 THE AQUARIUM.

intended to remain, and the rest of the water should be syphoned
on. This is best effected by means of a piece of feeding-bottle
tubing, a water-can full of tap water being placed at a higher level
than the aquarium, such as on the top of a pair of steps, the
shorter end of the tube being in the can, the longer in the aqua-
rium. By this means the minimum disturbance of the contents is
effected, and the water more readily settles down bright.

This done, the aquarium is ready for its animal life ; and in
the selection of the various members of the happy family no small
degree of care is requisite, otherwise the many are apt to suffer for
the benefit of the few, for numbers of aquatic insects are most
voracious and carnivorous, even cannibalistic in their habits. The
first selection should be directed to molluscs. A few water-snails
are indispensable ; not only do they keep the plants within bounds,
and by their excreta form a suitable soil for continued healthy
growth, but by browsing on the glass sides clean away the confer-
void growths, which would otherwise speedily obscure the view.
The best for the purpose we find to be Li?jmea auricularia^ which
may be found crawling on the bottom of most muddy ditches. It
has a very wide-mouthed shell, and is often prettily blotched and
marked ; its food consists almost entirely of the minute confervse,
which are apt to grow too luxuriantly if the aquarium is exposed
to strong daylight. It is preferable to the larger Limnea stagnalis,
which is generally recommended, for the latter will attack the
growing plants. Z. stagnalis is known at once by its larger size
and longer corkscrew-pointed shell. Another genus of useful
snails is Flanorbis, known by its wheel- or "ammonite "- like shell.
Two species — F. corneus and P. marginatus — are most frequently
met with, and both are excellent for our purpose. Another snail
is interesting, but less often come across — Paludiiia vivipara —
known by its resemblance to the familiar periwinkle, and, like it,
possessing a horny scale or shield, called the operculum, with
which, when the animal retires within, the mouth of the shell is
closed. It also has a peculiar elephant-like proboscis, at the
extremity of which the mouth is placed. This snail is generally
found upon wooden stakes or posts which stand in deepish water,
and may be captured by running the hand along the surface, when
they may be felt and detached where they cannot be seen.

THE AQUARIUM. 99

Among the bivalves, a specimen or two of the cockle-like
SphcBriwn corneum and half a-dozen of the pea-shells {Pisidiimi)
may be included. At the outside not more than a couple of
dozen molluscs altogether should be introduced at once, since, if
their surroundings are suitable, they increase very rapidly. The
tendency with beginners is to overstock with animal life. To pre-
vent disappointment, it is better to err on the other side, for excess
of vegetable life is less likely to give bad results than too many
animals. When the crop of confervae grows so fast that the snails
cannot keep it within bounds, we have found an old tooth-brush
fastened to the end of a glass rod a very useful weapon in cleaning
the glass. After snails, a few beetles should be taken, but only
the smaller lynds, since several of the larger ones are very
voracious. This is particularly the case with Dytiscus marginalise
the common large pond beetle, which both in its larval and perfect
state of development, should be avoided, for if introduced, it
would speedily devour every other living animal. Another
voracious beetle, smaller than D. marginalise is Z?, {Ilibias) ater^
a shining black species, which should also be given a wide berth.
Exception in the bannings of the large beetles must be made in
favour of the largest, the great water beetle, Hydrophilus piceus,
which is entirely harmless. It is not very common, but occurs in
the neighbourhood of London. It may be known by its appear-
ance and size, resembling a female stag-beetle, and by the beauti-
ful play of colours shown on the elytra when swimming in the
water. Another harmless and very active beetle, constantly on
the move, somewhat resembles a flattened acorn in size and shape,
is Agabus agilis. A large flattened beetle^ Acilius canaliculatus, is
also to be recommended, for although carnivorous, it will not
generally attack living prey if it can find dead animal matter. It
therefore becomes a very useful scavenger. Most of the smaller
beetles may be included ; among others, Agabus maculatus, which
has blackish elytra with white spots, and also Laccophilus minutus^
The small oval Hyphidrus ovatus, always on the move, is also an
attractive insect in captivity ; with it may be classed Cnemidotus
ccesus, which may be known by its grooved and dotted wing-cases
of yellow colour. A few whirligig beetles — the Httle black Gyrinus

100 THE AQUARIUM.

natator—^\\ou\d be captured ; they are quite inoffensive. It
should be borne in mind that all these beetles are not entirely
aquatic ; consequently, if kept in an uncovered aquarium, are apt
in summer to take flight during the night. They should be kept
in a vessel provided with a cover.

A very common but curious insect is the water scorpion,
Nepacwereus, a member of the Hefnipiera. Although far from
being a vegetarian, it may be safely kept in an aquarium with
other things if occasionally fed with flies. These it catches with
its first pair of legs, and thrusts it upon its sharp-pointed snout,
through which it extracts their blood. Its appearance resembles
a small flattened leaf, grey above, and often reddish beneath, with
a long pin-like tail. It scrambles about in the water upon the
weeds or rests on the surface with its fore-legs extended on the
watch for flies. There is another water-scorpion, Nepa lineatiis,
but much rarer than this, which is a very close approach to the
exotic stick insect in appearance ; in fact, when drawn from the
water and feigning death, it is difficult to recognise a living insect.
This is similar to the common water-scorpion in its habits, and in
attitude recalls the well-known ' praying mantis ' while laying in
wait for flies. Both these insects are very subject to the attacks
of parasitic acari, which will seem adhering to them like minia-
ture sheep-ticks.

No aquarium should be without a couple of water-boatmen,
Notonecta glauca. They may be known at once by their curious
action when swimming on the back, recalling an out-rigged
scuUing-boat. These, too, are not above staying their stomachs
with their fellow captives, but will not do so if fed on flies, which
they will even seize from the fingers, clasping their prey as though
nursing it, and keeping it beneath the surface until it is drowned.
There are three common species — one large, and with hard,
coloured wing cases ; the others flatter, and with elytra reticulated,
Conixa striata and affinis. Unfortunately, the first preys greedily
upon the latter two, so that they cannot be kept together for long.

Among larvae we have a wide selection of curious forms, which
may be successfully reared, but in collecting we should be
cautious not to include any with large sickle-shaped or knife-like
jaws ; such are certain to be carnivorous and predatory. A little

THE AQUARIUM. 101

practice will soon enable the collector to distinguish between the
murderous crew and the innocent ; but not always, for some of
the former positively wear a moveable mask, like the highwaymen,
behind which they hide their weapons of offence. An eye should
be kept on the aquarium, and any aggressive member of the stock
removed by means of a very small muslin net, or a wide glass
tube used as a pipette ; an inverted thistle-funnel is useful for this
purpose. A few caddis worms (Phryganeidce) should be taken for
the quaint appearance of their cases, different species constructing
their curious abodes with various material ; only one or two
specimens should be included however, otherwise the stock of
plants will suffer. Another animal, the water-spider, Argynotea
aquatica, deserves a place. It may be found in any pond, running
on the'surface, and then disappearing with the metallic sheen of a
globule of mercury. When captured, it should be carried home
in a box with moist weed, and not in water, for if shaken about in
water, it speedily drowns.

Among the more highly-developed creatures, a few tadpoles
deserve a place. In early spring the spawn may readily be found,
that of frogs in masses, toads in strings, and newts wrapped in
leaves. A few eggs should be placed in the aquarium ; from this
the development of the young batrachians is most interesting to
watch.

If it be desired to include fishes, a single specimen, or a pair,
male and female, of sticklebacks may be added. If, however,
the aquarium be intended as a nursery for microscopic pond
life . . this addition is hardly to be recommended.

For collecting the minuter forms, which in the limit of this
note cannot be noticed seriatim, a brother pharmacist adopts the
following plan, which we have followed with great success. A
small filter bag is made of fine cambric, and fastened to a ring of
copper wire, which is afterwards twisted out on each side of the
ring, and attached to two long meat-skewers. Arrived at the
pond, the skewers are stuck in the bank, supporting the filter be-
tween them, and the latter is kept charged with pond water, ladling
with a wide-mouthed bottle attached to a stick. By this means,
myriads of minute forms of life, such as Hydrse, Desmids, Cyclops,
Daphnia, etc., are captured in a few moments ; the ' concentrated

102 THE ROYAL NATURAL HISTORY.

infusion ' is then transferred to a larger bottle, which is emptied
into the aquarium with as little delay as possible. By this means
food is supplied to the inmates, and numerous curious additions
obtained to the permanent stock. The Hydras are very attractive
creatures, of which two kinds may be expected in most localities,
H. fusca of a dull greyish or pinkish tinge, and H, viridis. a bright
green ; the latter is interesting, being an animal which owes its
colours to chlorophyll.

Among the creatures to be excluded we must name the com-
mon water wood-louse, Asellus aquaficus, and the fresh water
shrimp, Gammarus pulex^ which, although said to be carnivorous
in their habits, we find to be very destructive to plants, biting
through the growing stems and thus cutting them adrift.

With regard to apparatus for collecting, the only indispensable
article is a good pair of eyes. A vasculum holding a few quinine
vials, and a small muslin net, which can be tied to the end of a
walking-stick, is all that is needed ; the net may be supplemented
with a bottle similarly attached, for the smaller forms of life,
which may be picked out from the dippings by a glass tube used
as a pipette. These may be usefully supplemented by the filter-
ing arrangement which we have described above."

"^be IRopl matuial "Ibistor?."

^

W'" E have to congratulate both the editor and the publishers
on the completion of the second volume of this fine work.
The volume in front of us concludes the account of the
Carnivora, and includes the whole of the order of Ungulates,
finishing with the order Sirenia.

Where all is so good, it is difiicult to quote any especial part
without citing so much that the publishers would be down upon
us for pirating. But we cannot resist giving the following anecdote
relating to " the lasting and pernicious effects of even a drop of
skunk secretion." The story is told by Mr. W. H. Hudson about

* Edited by Richard Lydekker, B.A., F.R.S. (London: F. Warne and
Co. Published monthly. Price i/-) Vol. IL (Parts 7—12), 1894.

THE ROYAL NATURAL HISTORY. 103

a settler who started one evening to ride to a dance at a neigh-
bour's house : — " It is a dark, windy evening, but there is a con-
venient bridle-path through the dense thicket of giant thistles, and
striking it he puts his horse into a swinging gallop. Unhappily,
the path is already occupied by a skunk, invisible in the darkness,
that, in obedience to the promptings of its insane instinct, refuses
to get out of it, until the flying hoofs hit it and send it like a well-
kicked football into the thistles. But the forefeet of the horse, up
as high as his knees perhaps, have been sprinkled, and the rider^
after coming out into the open, dismounts and walks away twenty
yards from his animal, and literally smells himself all over, and
with a feeling of profound relief pronounces himself clean. Not
the minutest drop of the diabolical spray has touched his dancing-
shoes. Springing into the saddle, he proceeds to his journey's
end and is warmly welcomed by his host. In a little while people
begin exchanging whispers and significant glances. . . . Ladies
cough and put their handkerchiefs to their noses, and presently
begin to feel faint and retire from the room. Our hero begins to
notice that there is something wrong, and presently discovers its
cause. He, unhappily, has been the last person to remark that
familiar but most abominable odour, rising like a deadly exhalation
from the floor, conquering all other odours, and every moment
becoming more powerful. A drop has touched his shoes after all."
Our space is now exhausted, but we must call attention to the
descriptions of the general characteristics of the several orders,
which Mr. Lydekker has made a special feature.

The work is profusely illustrated with most excellent woodcuts.
We give on the opposite page a figure representing Brown Bears on
the march, in which the awkward and ludicrous movements of the
animals are admirably depicted. The plates are also extremely
good, with the exception, in our opinion, of the plate of Fallow
Deer, which does not come up quite to the standard of the others,
and we cannot say that we quite admire the plate of the Indian
Elephant, whose forequarters appear to be a little too thin for his
height. But these, perhaps, may be mere trivialities. The highest
praise we can give to Mr. L3'dekker is that we consider the work
should be on every naturalist's table.

104

THE ROYAL NATURAL HISTORY.

^ ^ IT

[ 105 ]

flDicro0copicaI technique.

Compiled by W.H.B.

Hodgrson's Compressor.-This simple form of parallel compres-
sor has been devised by Mr. J. V. Hodgson, of Birmingham, to
meet the requirements of those who wish for an effective instru-
ment at a moderate cost, and at the same time permitting the use
of dark ground and oblique illumination of wide angle. It con-
sists of a plate of brass, 3 in. by i3/^ in., with a central hole ^ in.

in diameter, over which is cemented a cover-glass. On either side
of the hole IS an upright peg. The upper plate is diamond shaped
and the central hole corresponds to that in the lower plate The
two ends of the diamond carry stout tubes fitting closely to the
upright pegs of the lower plate, and enable it to be adjusted to a
nicety^ The upper plate cannot be raised by one hand alone.
Mr. Hodgson also makes a form in which the cover-glass on the
lower plate is sunk below the level, while the upper plate is

106 MICROSCOPICAL TECHNIQUE.

bevelled to admit of high powers being used close to the edge, as
in illustration. The compressors can also be obtained thickly
nickelled, thus preventing tarnishing, which to some persons is so
objectionable.

Filtration of Agar- Agar .■^— Dr. W. S. C. Symmers finds that
the ordinary methods of filtering agar-agar takes too much time.
He employs the method used at the Pasteur Institute. The
important requisite in this method is the filter-paper known as
" papier chardin," made by Cogit et Cie. The agar-agar is heated
in an autoclave to 120° C. and poured at once on to the filter-
paper in a cold funnel. The agar-agar filters as rapidly as nutrient
gelatine does in the ordinary method, and a litre may be obtained
in half-an-hour.

Embedding Medium.— M. Camille Brunotte describes in the
Journal de Botatiique a new mode of utilising gelatine as an embed-
ding medium, by which the action of heat upon tissues containing
water can be avoided. Thin sheet gelatine, 2ogm.,is dissolved
by the aid of heat in 100 gm. of distilled water. The solution is
filtered through fine linen and 30 — 40 cm. of glacial acetic acid^
and a gram of bichloride of mercury added. This addition keeps
the gelatine liquid at the ordinary temperature (15^ C.) and of the
consistence of thick syrup. To embed the material, a small
quantity of the liquid gelatine is poured into a little mould made
of thick absorbent paper (papier buvard), and the object placed in
it. The liquid being transparent, the position of the object by
immersion in water can be easily arranged. The whole is then
immersed in alcohol, which hardens the mass of gelatine.

In cases in which alcohol might render cloudy the cell con-
tents, picric acid, bichromate of potassium, or chrome alum may
be used for hardening the gelatine, but these re-agents require a
much longer time to act. The sections, as soon as cut, can be
mounted in gelatine or glycerine, or can, if required, be quickly
freed from the thin coating of gelatine that surrounds them.

Fixing Celloidin Sections.— Prof H. E. Summers, of Cornell
University (U.S.A.), recommends the following method of fixing
celloidin sections : —

" The sections are first placed in 95 per cent, alcohol for a

* British Medical Journal^ No. 1765, 1894, p. 951.

MICROSCOPICAL TECHNIQUE. 107

minute or two ; they are then arranged on a slide, and the super-
fluous alcohol drained off by tipping the slide, after which sulphu-
ric ether-vapour is poured over them from a bottle partly filled
with liquid ether. Under this treatment the celloidin softens and
becomes transparent. The slide may then be immersed in 80 per
cent, alcohol, and the section afterwards stained, anhydrated, and
mounted in balsam by the usual process, as the ether treatment
serves to fasten the sections firmly to the slide. — -Jour rial Recon-
structives.

Styrax for Mounting.— Sty rax is being recommended in Eng-
land and America as a mounting medium in certain cases. As
the balsam of the shops is always full of dirt and impurities, it
requires preparation before it can be used in microscopy. The
best plan is to to dissolve and filter it. To do this, dissolve a
portion of the styrax in sufficient benzol to make a liquid of a thin
syrupy consistence, and filter through two thicknesses of Swedish
filter-paper. Use a large filtering-funnel, fitted with a cap to
prevent evaporation, and let the filtering-paper reach not much
more than midway up the sides. Should the medium become too
thick to pass through, add more benzol. The product will be too
thin to use at once, and may be set aside, properly protected from
dust, until sufficient benzol evaporates.

Wheat and Rye Starch.*— E. Guenez points out that these
starches possess very similar characters, and it is difficult at times
to say decidedly that a given sample consists of one rather than
the other. To distinguish the two kinds, he recommends that a
little of the material be mounted in water for examination with
the microscope. The wheat-starch will then be seen to contain
comparatively few split grains, which possess an isolated fracture
situated near the edge or proceeding from the centre to the circum-
ference. In the case of rye starch the split grains are more nume-
rous, and possess a star-shaped fracture with three or four branches,
apparently originating in the centre of the grain and rarely reach-
ing the edge. Some grains may also be found which have only a

*Bull. de PharjH. de Bordeaux, xxxiv., 289, in Pharm. /ourn., Nov. 3, 1894,

P- 356.

108 MICROSCOPICAL TECHNIQUE.

linear crack ; but this will be larger in the centre of the grain than
towards the edges, just the reverse of what occurs in wheat.

Iron-Haematoxylin and Centrosomes.'^— Iron-haematoxylin has
been used by Heidenhain in the study of the centrosomes and
astrospheres. The original process, which is also repeated in the
new modification, was the following : —

Fine sections of preparations in sublimate are fixed on the
slide by means of distilled water, dehydrated with alcohol con-
taining iodine, and exposed to a \\ per cent, solution of
ammonio-ferric alum. The crystals of this salt should be clear
violet in colour; if they are yellowish and opaque, they have
suffered from exposure to air and are no longer fit for use.
The solution must be made cold, as the salt is decomposed
by heat. The slide is next washed with distilled water and
then placed in a i^ per cent, solution of Hcematoxylinwn purissi-
mum (Griibler). The over-stained sections are then again treated
with the iron-alum solution used before, in order to remove the
superfluous colour. The process of extraction must be followed
under the microscope and continued until thecell protoplasm is com-
pletely decolourised, and the chromatin network of the nucleus
becomes clear. One may interrupt the differentiating process any
moment by washing with fresh water, and then continue it. When
the extraction of the stain has been carried far enough, the slide
should be washed fifteen minutes in fresh water and mounted in
the usual way in balsam.

Heidenhain noticed that when the differentiation was effected
quickly, the centrosomes were stained in greater number than when
the process occupied a long time. It seemed, therefore, that the
defects of the method might be corrected if a way could be found by
which the decolouring process could be hastened. How could the
cytoplasm be freed from the stain in the shortest time ? Assuming
that a stain acts by chemical combination, it seemed probable that
the process of extraction might be hastened, if the receptivity of
the cytoplasm could be at least partially saturated before the appli-
cation of the haematoxylin. Accordingly, Heidenhain selected as
preliminary stains (" Vorfarben ") such as afl'ect the cytoplasm and

* Americcun Naturalist^ xxviii. (1894), PP- 97^ — 977-

MICROSCOPICAL TECHNIQUE. 109

the nucleus, and leave the centrosomes unstained. Thus, the che-
mical affinities of the centrosomes for the haematoxylin would
remain at full strength ; while those of the cytoplasm and nucleus
would be more or less saturated, and to the same extent weakened
for the hsematoxylin. In this way the process of extraction was
brought under some control, and the method greatly improved.

Stains reached in this way are called " subtractive." Bordeaux
R., Anilin blue and Methyl-eosin were employed as preliminary
stains. Bordeaux R. proved to be the best. In preparations that
have been successfully differentiated as to the centrosomes, the
nucleus and its chromatin are almost colourless, so that the cen-
trosome may be easily studied, even when it lies behind the
nucleus. The nucleoli remain strongly stained.

The Chromatin. — Heidenhain shows that there are two kinds
of chromatin to be distinguished — namely, an oxychromatin brought
out by acid anilin stains {e.g,, Rubin S.), and a basichromatiii, which
is brought out by basic anilin stains {e.g., Methyl green). The "basi-
chromatin " is the chromatin of Flemming and authors in general.

The differentiation of the two chromatins can only be accom-
plished when the nucleus is exposed at the same time to both acid
and basic anilin colours, as is the case when Biondi's solution and
Ehrlich's triacid are used.

If one mixes ammonium vanadate with haematoxylinum pur
(Griibler), a blue stain is obtained which stains cytoplasm and oxy-
chromatift strongly, while the basichromatin is often left nearly
colourless. The two chromatins probably differ only in the
amount of phosphorus present, basichromatin containing more,
oxychromatin less.

Aluminium has the property, when used as a pencil, of leaving
an indelible mark on glass or any other substance having a siliceous
base. A deposition of the metal takes place, and, while this may
be removed by a suitable acid wash, the mark itself cannot be
removed by rubbing or washing. Magnesium, zinc, and cadmium
have a similar property, but the mark of magnesium is easily
removed, the application of zinc requires a wheel, and zinc and cad-
mium tarnish ; while aluminium is permanent and remains bright.

[ no ]
IWotes.

A new material for pathological casts is advocated by Dr. C. W.
Cathcart in the October number of the Journal of Pathology and
Bacteriology. It is obvious that if it is of service for pathological
reproductions, its usefulness can be extended to many other sub-
jects. In searching for some material for casts, Dr. Cathcart
turned his attention to the papier-mache methods. His principal
difficulty was to get surface detail, and after trying many papers he
found none so satisfactory as the " Robosal" blotting-paper, which
is made of wood pulp, and while very strong and tough while dry,
is exceedingly absorbent, and when wet becomes very soft and
pliable. It is made of various thicknesses and almost any shade
of colour, although white is preferable, because it may be coloured
afterwards according to the specimen.

The surface detail on casts made of " Robosal " is quite fine
enough for ordinary purposes. Thus, the skin markings on the
back of the hand can be brought out distinctly. It is much
cheaper than plaster of Paris, and being only a hollow shell of
paper weighs in ounces what the other weighs in pounds. It is
tough and can be knocked about with impunity. The interior of
the moulds., which of course are of plaster of Paris, must be well
smeared with vaseline, tallow, or other greasy substance to which
paste will not stick.

The method is described as follows : — " The casts are made of
'Robosal' blotting-paper (Messrs. Robinson, Liverpool), about
the thickness of ordinary writing-paper, and ordinary flour-paste.
After the mould has been prepared as above, a piece of ' Robosal '
is laid on a flat plate and the paste is rubbed into it on both sides
till the paper is Hmp and soft. While the softened paper is still
lying flat on the plate, scraps are torn from it so as to leave their
edges frayed and thin. If necessary, the paper can be torn into
thin films, where finer markings are to be cast. Beginning at the
margin of the mould on one side, the operator lays on a piece of
the torn softened paper, and presses it with his finger or a stiff
brush firmly into the irregularities of the mould. Overlapping this
he puts on another piece, and another and so on, until the whole
of the mould is covered, being careful to avoid wrinkling the soft
paper. Over the first layer a second is laid, and sometimes a
third. For small casts this will suffice, but for larger casts an
additional layer of ' rope,' brown paper, or of muslin, soaked in
paste as before, is to be applied in the same way. It is advisable
to put on all the desired layers at once, so that in drying they may
shrink uniformly. It is also important to let the paper stick to
the margin of the mould by leaving them ungreased. This insures

NOTES. Ill

a good shape. When all the required layers have been put on,
the cast is dried. Slow drying in free air and warmth is preferable,
and takes from twenty-four to forty-eight hours ; but quicker dry-
ing in an oven may be used if need be. When the cast is dry,
the inside is painted over with a coat of spirit varnish. The paper
is then cut from the mould at the margins, and the cast will be
found to have shrunk slightly from the surface, and thus be loose.
With care, it can then be worked out from the crevices and'
corners. The rough edges are next trimmed with scissors and
bound with blue paper. A thin layer of size is then painted over
the cast. As soon as this is dry, the necessary painting can be
carried out. Oil colours should be used, mixed with turpentine if
a dry surface is wanted, or mixed with plenty of megilp, and
afterwards varnished, if a moist surface is to be imitated. The
time required for making each cast is about the same with papier-
mache as with other materials."

How ARE Young Spiders Fed ? — In my rambles for botani-
cal specimens in the last three years, many new and curious things
have been thrust upon my attention in the insect world, and these
I have recorded for future use. One fact in particular struck my
attention, and I herewith submit it to the readers of Science, partly
to record the fact, and partly to ask if any other readers have
ever observed a similar fact. We have been taught by the best
works on spiders, that the young of spiders derive their food
mostly from the atmosphere. The "Encyclopaedia Britannica "
confirms this view.

On the 19th June, 1891, I discovered in a ploughed field an
enormous spider, of the Lycosidse species, which was ij inches
long. She presented a very curious appearance, being covered
with scores of tiny spiders from one end of her body to the other.
When I touched her with a weed stem, the young spiders scamper-
ed oft' at a lively rate, only to return when left to themselves. The
spinneretts and abdomen of the mother spider were greatly dis-
tended. Suddenly there was a copious flow of white liquid, which
the young greedily devoured. Examining the fluid under my
microscope, I was fully convinced that this was veritable milk, and
that this spider at least nursed her young, instead of bringing them
up on atmospheric moisture. I shall be glad to know if any
reader of Science has ever observed a similar occurrence.

Naples, N.Y. John W. Sanborn.

Purification of Water by Green Plants'". — The preva-
lent idea that green plants (flowering plants and algae) growing in

*Pharm. /ourn., Nov. 5, 1894, p. 356.

112 NOTES.

running water add to its impurity and unfitness for drinking pur-
poses, has long been shown to be erroneous. As long as they are
in a growing condition, they can only tend to purify the water by
giving out oxygen into it. In a paper in the Archives fiir Hygien
(1894, No. 2), Dr. T. Bokorny maintains that aquatic bacteria
also have a share in the purification of water, so long as it con-
tains a considerable quantity of organic matter. A series of
experiments carried on by the author showed the algae are capable
of decomposing fatty acids, such as butyric and valerianic, as also
glucose, leucin, and tyrosin.

Canada Balsam Fir. — The following note from the Drug
Reporter will be interesting to microscopists : —

" While there has been little or no increase in the consump-
tion of Canada balsam within the past five years, the supply has
been gradually diminishing, partly as a result of natural conditions,
and partly because the work of gathering has been, to an extent,
neglected. The collection of balsam fir is not a regular industry,
but has been prosecuted by lumbermen and labourers in other
fields, who devoted their leisure to it. So long as the balsam
could be obtained near by the markets to which the gatherers
bring it, the supply was ample and regular ; but with the cutting-
down of the Canadian forests for timber the source of supply has
been further and further removed from commercial centres, and the
collection of the balsam has not proved profitable enough, for a
number of years past, to encourage those who heretofore engaged
in it to continue to bring it to market.

In some years the supply has been larger than in others, owing
to the scarcity of other employment, and in view of the wide-
spread distress among the labouring classes, including the Canadian
lumberman, during the past eighteen months or more, it would be
natural to expect that these people would have turned their attention
to the gathering of balsam as a means of livehhood. Such, how-
ever, does not appear to have been the case, for according to
reliable reports the quantity collected this year was very small, not
exceeding fifty barrels. This small yield was partly due to wet
weather toward the end of the gathering season — late August and
early September — but the chief reason for it is that the gatherers
found it unprofitable to go so far into the interior for the balsam
as they are now compelled to go.

[ 113 ] _ ^^^

^be (Branb fall6 of Xabra&orX^^^ V'

AN account of his visit to the Grand Falls of Labrador has
been given by Henry G. Bryant, of Philadelphia, in the
Century Magazine and in a Bulletm of the Geographical
Club of Philadelphia. They are situated on the Grand or Hamil-
ton Kiver, which rises in the lakes of the upland region of the
peninsula and flows in a general south-easterly direction into
Hamilton Inlet — the great arm of the sea which, under various
names, penetrates into the interior a distance of one hundred and
fifty miles. No scientific explorer has advanced far into the
country, and all that is known of it is derived from vague informa-
tion furnished by Indians, a few missionaries, and the Hudson
Bay Company's men. The first white man to visit and describe
the falls was John McLean, of the Hudson Bay Company, in 1839.
They were visited twenty years afterward by Joseph McPherson.
These are the only white men who are known to have seen the
Grand Falls till the summer of 1891, when Mr. Bryant and an
expedition from Bowdoin College reached them independently of
one another. Mr, Bryant, accompanied by Prof. C. A. Kenaston,
of Washington, and a Scotch and an Indian assistant, left North-
west Eiver Post, at the head of Hamilton Bay, on August 3rd, to
proceed up the stream by canoe. On the 27th they reached the
point where the further navigation of the stream is obstructed by
rapids, whence they proceeded overland and reached the Falls
Sept. 2nd. " A single glance showed that we had before us one of

the greatest waterfalls in the world A mile above the

main leap the river is a noble stream four hundred yards wide,
already flowing at an accelerated speed. Four rapids, marking
successive depressions in the river bed, intervene between this point
and the falls. ... An immense volume of water precipitates
itself over the rocky ledge, and under favourable conditions the
roar of the cataract can be heard for twenty miles. Below the
falls, the river, turning to the south-east, pursues its maddened
career for twenty-five miles shut in by vertical cliffs of gneissic rock,
which rises in places to a height of four hundred feet. The rocky
banks above and below the falls are thickly wooded with furs and
spruces, among which the graceful form of the white birch appears
in places." The height of the falls was found, by as accurate a
measurement as could be made with cord, to be three hundred
and sixteen feet.

* Popular Science Monthly. %

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. i

[ 114 ]

1Revievo0*

A New English Dictionary, on Historical Principles,
founded mainly on the materials collected by the Philological Society. Edited
by James A. H. Murray. D to Deceit, commencing Vol. 3 ; F to Fang,
commencing V^ol. 4, by Henry Bradley, Hon. M.A. Oxon. (Oxford : The
Clarendon Press. 1894.) Price 3/6 and 2/6.

These two parts are compiled with the same care as has marked all the
previous issued parts. The past and present method of spelling, with illus-
tration of its use, are given of every word from the loth century. The letters
A, B, C and E have already been published, and we are pleased to notice
that one section, at least of each of the letters D and F, will be published
quarterly during 1895, at 2/6 each part. It is a grand work.

McDougall's Higher Grade Arithmetic in Theory and
Practice. Cr. 8vo, pp. vi. — 199. (London : McDougall's Educational Co.,
4 Ludgate Square.)

In this book, the author has reasoned out and demonstrated to pupil
teachers and others so much of the science of arithmetic as is needed for exam-
inations in the Education Department. Commercial Arithmetic has received
special attention, and a chapter is devated to the Metric System.

A New School Method. Part 3. How to teach the class

subjects — Geography, Grammar, History, and Elementary Science. By
Joseph H. Cowham. Cr. 8vo, pp. 376. (London : Westminster School Book
Depot and Simpkin, Marshall and Co. 1894.) Price 1/6.

On a former occasion, we noticed the first two volumes of this series.
The object of the author is to show how the teacher may combine the highest
training, with the best instruction. We are struck with the simplicity of the
method employed, and with the possible satisfactory results. There are a
number of helpful illustrations.

A Monograph of the Land and Fresh-Water MoUusca of the
British Isles. By John W. Taylor, F.S.S., with the assistance of W. D. Roe-
buck, the late Chas. Ashford, and others. Part I. October, 1894. (Leeds :
Taylor Bros.) Price 6/-, or by subscription 5/- (5/3 post free.)

The object in issuing the present work is to bring together, as far as prac-
ticable, all reliable information bearing on the study, and thus form a standard
work of reference as well as a reliable text book upon British Land and Fresh
water shells. The first volume will be devoted to the general treatment of the
subject, the different forms and characters of the shells, the morphology of the
animal and description of the structure and functions of the various organs of
its body.

The work is profusely illustrated, there being 138 wood cuts and one
coloured plate in the first part. We are desired to state that the author will be
pleased to receive assistance from Microscopists and Micro-photographers on
the subjects of dentition, microscopic structure, and other peculiarities. The
work promises to be a very important one, and we hope to refer to it again in
our next.

REVIEWS. 115

European Butterflies and Moths. Cr. 4to. (London

Cassell and Co.)

Parts I to 7 of this very important work have reached us. Each number
contains a superbly coloured plate showing the butterflies in all their stages,
together with the food plants of the larvae. No. i contains also a plain plate
describing very thoroughly the anatomy of the Lipidoptera. The parts are
pubhshed monthly at 6d. each.

The Birds about us. By Charles Conrad Abbott, M.D.
8vo, pp. 288. (Philadelphia, U.S.A. : J. B. Lippincott Co. 1895.)

A thoroughly interesting book is now before us. In the introduction,
comprising about a dozen pages, the author gives a pleasing history of bird-life
generally, and hopes that the book may add something towards the growing
disposition to cultivate rather than persecute our feathered friends. There are
25 chapters, in which the different families of birds are very interestingly des-
cribed. We find, also, there are 24 plates, principally showing nests and
homes of birds, and 50 illustrations in the text.

A Dictionary of Birds. By Alfred Newton, assisted by
Hans Gadow and others. Part 3. 8vo, pp. 577 — 832. (London: Adam and
Charles Black. 1894.) Price j^jS.

This part reached us just as we were going to press. It covers from Moa
to Sheathbill, and gives besides descriptions of those birds whose names fall
between these letters, very good articles on the Muscular and Nervous Sys-
tems, Nidification, etc. With the publishers' permission we shall hope to refer
to this interesting work again.

The Earth : An Introduction to the Study of Inorganic
Nature. By Evan W. Small. Cr. 8vo, pp. viii. — 220. (London : Methuen
and Co. 1894.) Price 2/6.

One of the University Extension series contains the substance of a course
of lectures delivered in various centres during the winters of 1884 — 90. They
are well adapted for the general reader who wishes to gain a knowledge of the
more striking phenomena of the earth. The subjects treated of are, The Earth
as a Planet ; The Materials of the Earth ; Work and Energy ; How the
Materials of the Earth's Crust were formed ; and the Evolution of the Earth.
There are a number of illustrations.

Ponds and Rock Pools, with hints for collecting and the
management of the Micro-Aquarium. By Henry Scherren. Cr. 8vo, pp. 208.
(London : Religious Tract Society. 1894.) Price 2/6.

The chapters in this book have been considerably enlarged from the pages
of The Leisure Hour, in which they originally appeared. They treat of Pond
and Rock-Pool Hunting ; The Beginning of Life ; Sponges and Stinging
Animals ; Worms ; Star-Fishes, Arthropods, and Molluscs ; and The Micro-
Aquarium. There are 66 illustrations.

A Pocket Flora of Edinburgh and the surrounding District.
By C. O. Sonntag. Fscap. 8vo, pp. xii. — 246. (London : Williams and
Norgate. 1894.)

We have here a collection.and full description of the Phanerogamic and
the principal Cryptogamic plants classified after the Natural System, with an
Artificial Key and a Glossary of Botanical terms, besides a folding map of the
County of Edinburgh and surrounding district.

This little book has been compiled with much care, a great number of
localities favoured by the individual plants are given, the author only specially
indicating his own in the case of rare plants. Botanists, especially those living
in the locality, will find this an invaluable pocket companion.

116 KEVIEWS.

Die Naturlichen Pflanzenfamilien. By A. Engler and
K. Prantl. Parts io6, 7, 8. (London : Williams and Norgate. Leipzig :
Wilhelm Engelmann. 1894.)

We have here the completion of the third and parts of the fourth volume.
The families treated of are Cactacese by K. Schumann (concluded); Geissolo-
maceas, Penacacese, Oliniaceae, Thymelacacese, and Ekoagnacese by E. Gilg ;
and Borraginaceae by M. Gurke ; Gesneriacese (concluded) ; and Columelli-
acese by Karl Fritsch ; and Bignoniacese by K. Schumann. There are 49 fine
illustrations, composed of 369 figures.

Half-Hours with the Microscope. By Edwin Lankaster,

M.D. Fscap. 8vo, pp. 130. (London: W. H. Allen. 1894.)

The nineteenth edition of this useful little book is now before us. Con-
sidering the present advanced state of Microscopy we should have liked to have
seen an entirely new written and up-to-date book, but the volume before us has
the appearance of having been printed from the stereo-plates of a former edition.
There are one coloured and eight plain plates, besides other illustrations.

Directions for Laboratory Work in Bacteriology. By

Frederick G. Novy, Sc.D., M.D. 8vo, pp. 209. (Ann Arbor, Mich., U.S.A. :
George Wahr. 1894.)

The subject matter of this book has been arranged with reference to pro-
gressive work in the laboratory, and is intended to cover a course of daily
afternoon work for twelve weeks. No illustrations are given, but blank pages
are inserted that the student may add them. Very full and valuable formulae
and instructions are given. We consider the book a most useful one.

Practical Lessons in Elementary Biology for Junior

Students. By Peyton T. B. Beale, F.R.C.S., etc. P. 8vo, pp. vii.— 136.
(London : J. and A. Churchill. 1894.)

In the useful lessons which have been used with much success in the biolog-
ical section of King's College, the author treats in a practical manner those
points in the structure and life history of some organisms which are of great
importance, and in which the student frequently experiences a difficulty.

In each lesson the author indicates what may be seen and how important
parts may be practically demonstrated.

Outlines of Biology. By P. Chalmers Mitchell, M.A.,
F.G.S.,etc. Post 8vo, pp. XV. — 297. (London : Methuen and Co. 1894.) 6/-

This book is arranged in accordance with the syllabus of the Royal College
of Physicians and Surgeons for the guidance of candidates preparing for exam-
ination in Elementary Biology. It it divided into 18 chapters, commencing
with Protoplasm and the Building up of Protoplasm to The Dog Fish and the
Frog ; the last chapter being on Embryology. There are 74 illustrations in the
text.

Practical Physiology of Plants. By Francis Darwin,
M.A., F.R.S., and E. Hamilton Acton, M.A. Cr. 8vo, pp xxviii. — 321.
(Cambridge and London : The University Press. 1894.) Price 6/-.

Part I. of the book before us deals with general physiology, and Part II.
treats in a special manner of certain departments of physiology, viz. — Che-
mistry and Metabolism, and presupposes a greater amount of knowledge on
the part of the student.

REVIEWS. 117

Science Progress. No. io. (London : The Scientific Press.)

Price 2/6.

The December Number of this valuable Journal has reached us. It con-
tains the following articles : — On the Artificial Hatching of Marine Food-Fishes;
The Molecular Weight of Liquids ; The Origin of the Vascular Plants ; Recent
Researches in Thermal Metamorphism (Part 2) ; Continuous Current Dynamos
(Part 2) ; On the Morphological Value of the Attraction-Sphere (Part 2) ;
Kew Thermometers. There is also an Appendix of Chemical Literature for
October.

Common Things and Useful Information. Cr. 8vo, pp. 256.
(London : Thomas Nelson and Sons. 1895.) Price i/-.

One of the series of Royal Handbooks of General Knowledge ; gives in
Dictionary Form the more important points in Natural History, Elementary
Science, Physiology, and Common Things. These are all treated in full and
readable manner ; the book is nicely illustrated.

Theophrastus on Winds and Weather Signs. Translated
by Jas. G. Wood, M.A., LLB., F.G.S., and edited by G. J. Symons, F.R.S.
8vo, pp. 97. (London : Edward Stanford. 1894.)

This is a translation of the work of Theophrastus of Erebus, the favourite
pupil of Aristotle, on Winds and on Weather Signs, to which is added an Appen-
dix on the Direction, Number, and Nomenclature of the Winds in classical and
later times. There are 5 plates showing Maps of Greece and the Country
round Athens ; Horologium of Andronikos ; Aristotle's Diagrams ; and Table
of the Winds in the Museo Pio Clementino.

The Divining Rod: Its History, with full instructions for
finding subterranean springs. By J. F. Young and R. Robertson. Cr. 8vo, pp.
viii. — 138. (Clifton : J. Baker and Son. London : 25 Paternoster Sq. 1894.)
Price 1/6 net.

The authors explain here various methods of using the rod, and show how
it can be verified. The book also contains an essay, entitled "Are the claims
and pretensions of the Divining Rod valid and true ? "

Lectures on The Darwinian Theory. By the late Arthur
Milnes Marshall, M.A., M.D., B.Sc, F.R.S., etc. Edited by C. F. Marshall,
M.D., B.Sc, F.R.C.S.,etc. 8vo, pp. XX.-236. (London: D. Nutt. 1894.) 6/-

This volume consists of a series of lectures delivered in connection with the
Extension Lectures of the Victoria Univ., 1893, and are on the following sub-
jects : — History of the Theory of Evolution ; Artificial and Natural Selection ;
The Argument from Palaeontology ; from Embryology ; The Colours of Animals
and Plants ; Objections to the Darwinian Theory ; The Origin of the Verte-
brated Animals ; and the Life and Work of Darwin. There are 36 illustrations
and a photo-engraved Frontispiece of the Archaeopterix.

With the Woodlanders & By the Tide. Cr. Svo. pp. 305.
Annals of a Fishing Village. Cr. Svo, pp. viii. — 261.
From Spring to Fall, or When Life Stirs. Cr. Svo, pp. 244.

By "A Son of the Marshes." Edited by J. A. Owen. (London : William
Blackwood and Son. 1894.) Price 3/6 each.

It is with no small degree of pleasure that we read these exceeding inter-
esting little volumes from the pen of " A Son of the Marshes." There^ is a
peculiar fascmation in the author's style, which makes it impossible to find a
dry page in any number of his books, turn where you will.

118 REVIEWS.

WOODSIDE, BURNSIDE, HiLLSIDE, AND MaRSH. By J. W.
Tutt, F.E.S. Cr. 8vo, pp. v. — 241. (London : Swan Sonnenschein and Co.
1894.)

Mr. Tutt, the author of Random Recollectiotis of Woodside, Fen, and Hill,
which we were pleased to notice a short time ago, records in the volume before
us, in very readable language, a few more of the interesting phenomena which
are to be observed everywhere around us by those who take the trouble to look
for them, and to give such explanation of their causes as may easily be under-
stood even by those whose scientific knowledge is small. The book is nicely
illustrated and thoroughly interesting.

The Parish Councils' Act, 1894. A Popular Handbook
and complete guide to Elections of Parish Councillors, Rural and Urban Dis-
trict Councillors and Guardians. By J. Wallis Davies. Cr. 8vo, pp. xv. — 236.
(Bristol : J. Wright and Co. London : Simpkin, Marshall and Co. 1894.) 2/6.

The author, who is Solicitor and Secretary to the Parish Councils' Associ-
ation, gives his information in the form of questions and answers, his object
being to explain and elucidate the somewhat complicated act in an interesting
and pleasing manner. We believe the information is very concisely given.

Album of 24 English and Welsh Cathedrals. 410.

(London : Church Bells Office.) Price i/- net.

The 24 views of the various Cathedrals are nicely executed, and opposite
each is a short descriptive history. In the Preface is a short history of Cathe-
drals generally.

Monism, as connecting Religion and Science : The Confession
of Faith of a Man of Science. By Ernst Haeckel. Translated from the
German by J. Gilchrist, M.A., B.Sc, Ph.D. Crown 8vo, pp. viii. — 117.
(London : Adam and Charles Black. 1894.) Price 1/6 net.

The author declares his purpose to be twofold. First, to give expression to
that rational view of the world which is being forced upon us with such logical
vigour by the modern advancement of our knowledge of nature as a unity ;
and second. To establish a bond between religion and science.

Hereafter and Judgment : The Satan of the Old Testa-
ment ; The Satan of the New Testament. By the Rev. W. H. Tucker. Cr.
pp. 237. (London : Elliot Stock. 1894.)

We have read this book very carefully, but cannot say that we are pleased
with it. The author makes assertions which, to our lay mind, he does not prove.

An Outline of the Principles of Modern Theosophy. By
Claude Falls Wright. Cr. 8vo, pp. 192. (Boston [U.S.A.] : New England
Theosophical Corporation. 1894.)

Theosophy is to us an incomprehensible subject. The author here professes
to lay open the system which furnishes the key to every religion wherein is
buried the truth about our nature and destiny.

Carbon Printing. By E. J. Wall. Cr. 8vo, pp. 69. (London:
Hazell, Watson, and Viney. 1894.) Price i/-.

This is Vol. 8 of the Amateur Photographers' Library, its object being to
furnish historical as well as practical notes on the subject of this most perma-
nent of all printing processes. The instruction* given are concise and to the
purpose.

REVIEWS. 119

?HOTO-MiCROGRAPHY. By Dr. Henri Van Heurck. Re-edited

and Augmented by the Author from the fourth French edition, and translated
by Wynne E. Baxter, F.R.M.S., F.G.S. Cr. 4to, pp. 41. (London: Crosby,
Lockwood and Son. 1894.)

This work is extracted from Van Heurck's larger work on the Microscope.
There are 18 illustrations and a frontispiece showing Amphiphura pellucida,
X 2,000 diameters.

The British Journal Photographic Almanack, 1895.
Edited by J. Traill Taylor. (London: H. Greenwood.) Price i/- and 1/6.

A bulky volume of 1343 pages, containing a good deal of useful informa-
tion to the photographer, whether professional or amateur, and a large number
of advertisements, to which he will doubtless very frequently refer.

The Annual of the Universal Medical Sciences : A

yearly report of the progress of the general sanitary sciences throughout the
world, edited by Charles E. Sajous, M.D., and seventy associate editors,
assisted by over 200 corresponding editors, collaborators, and correspondents.
5 Vols. (London : F. Rebman. Philadelphia, New York, and Chicago : The
F. A. Davis Co. 1894.)

We have before us the seventh series of this extraordinary annual. It is
in our estimation the most important work of the kind published, as every
article of interest published throughout the world is epitomised here, the exact
reference being given so that, if desired, the entire article can be studied by
those desirous of doing so. Each volume has its own index, and in Vol. 5jis a
general index to the entire work, together with a list of all volumes and period-
icals consulted. It is illustrated with plain and coloured plates, woodcuts, etc.
No physician's or surgeon's library is complete without it.

The Flower of the Ocean : The Island of Madeira; A
resort for the Invalid ; a field for the Naturalist. By Surgeon-General C. A.
Gordon, M.D., C.E. 8vo, pp. x. — no. (London: Bailliere, Tindall, and
Cox. 1894.)

An interesting account of Madeira is given here. We find Historical
Notices, Meteorology, certain points relating to Hygiene and Medicine, the
Fauna of the Island, Agriculture and Viticulture, and some Medicinal Plants.

Landmarks in Gynaecology. 2 Vols. By Byron Robinson,
B.S., M.D. Fscap. 4to, pp. 220. (Detroit, Mich. : George S. Davis.)

Two volumes of The Physician's Leisure Library, contaming abstracts of
the author's lectures at the Chicago Post Graduate Medical School during the
past three years.

The Vaccination Question. By Arthur W. Hutton, M.A.
Cr, 8vo, pp. 128. (London: Methuen and Co. 1894.) Price 1/6.

The volume before us is a Letter addressed by permission to the Right Hon.
H. H. Asquith, Q.C., M.P., H. M. Principal Secretary of State for the Home
Department ; to which is added by way of Postscript some remarks on Dr.
Klein's Alleged Discovery.

The Chemist's and Druggist's Diary, 1895. Crown 4to.

(London : 42 Cannon Street.)

Besides the Diary, of which a page is given for each week, it contains a
number of articles of special interest to the Chemist and Druggist ; 42 pages
being devoted to Perfumes and how to make them. The Diary is interleaved
with blotting-paper. The volume is nicely bound.

120 REVIEWS.

The British and Colonial Druggist's Diary, 1895. 4to.

(London: 42 Bishopsgate Without, E.G.)

The fourth annual issue of this useful work contains a great deal of infor-
mation specially collected for, and particulary useful to all engaged in pharmarcy.
The diary is interleaved with blotting-paper and the whole is strongly bound.

Memories of Gospel Triumphs among the Jews during the

Victorian Era. By Rev. John Dunlop. Royal 8vo, pp. 510. (London ;
S. W. Partridge and Co. and The British Society's Office, 96 Great Russell St.
1894.) Price 5/-.

This very handsome book is the Jubilee Volume, prepared by the accom-
plished and genial Secretary of the British Society and Editor of the Jewish
Herald; it is a wonderful record of arguments, facts, and illustrations in favour
of missions to the Jews.

It contains biographical sketches of the founders of the society and early
missionaries, together with an account of the splendid work accomplished by
the society during the last 50 years. There are 250 portraits and illustrations,
and is splendidly bound. We are informed that the Queen and Prince of
Wales have each accepted a copy.

The Child's Pictorial. Crown 4to, pp. 192. (London:
Society for Promoting Christian Knowledge. 1894.) Price 2/-

Just the book for a present. It is full of plain and coloured pictures and
good tales, besides a series of illustrated articles on the Zoo by the Rev.
Thfiodore Wood, F.Z.S.

Stirring Tales of Colonial Adventure. A Book for

Boys. By Skipp Borlase. Cr. 8vo, pp, 376. (London : Frederick Warne
and Co. 1894.)

A series of eight stirring and instructive tales, such as must please every
boy who reads them. There are also some good illustrations.

A Salt- Water Hero. By Rev, E. A. Rand. Cr. 8vo, pp.

330. (New York : Thom. Whittaker.) Price $1-25 (5/-.)

This is an exceedingly interesting and nicely illustrated book for boys.
The author not only writes a thoroughly readable tale, but he manages at the
same time to instil some very manly thoughts into the mind of the reader.

The Lone Inn : A Mystery. By Fergus Hume. Cr. 8vo,

pp. 265. (London : Jarrold and Son. 1894.) Price 3/6.

A good tale, in which the mystery is well sustained. A shorter tale at end
of the volume is entitled " Professor Brankel's Secret," which we must leave the
reader to find out.

Games for Winter Evenings. — Messrs. A. N. Myers and Co.,
15 Berners St., Oxford St., W., have sent us a parcel of amusing games, of
which we enumerate the following : — The Manchester Ship Canal ; Cat and
Mice ; Ten Little Niggers running from Slavery to Freedom ; In Egypt with
the Pyramid ; The Owl Party ; and The Tower Bridge. This last is an inter-
esting model made in perforated cardboard, in many pieces, to be built and
fixed together, and forms, when properly arranged, a pretty model of this
celebrated structure.

[ 121 ]

Ipre&acioue an^ parasitic Enemiee of

tbe Hpbi&ea

(tncluMnci a Stu^p of 1b^per*=patasttes)»

By H. C. a. Vine. Plates VIII. and IX.

S it is only among the larval forms of the Syrphidae
that the aphis-eaters are to be found, it is of great
interest to identify if possible the respective larvae,
in order to ascertain in what species the aphidivor-
ous habit prevails. The principal difficulty
encountered in this study is the fact that fully 95
per cent, of the imagines, reared at great expendi-
ture of time and trouble, prove to be the common
Syrphus luniger, or some nearly allied variation. Another difficulty
is caused by the irregular periods of abstinence which more or less
affect all these larvae, and during which they not infrequently die
from the attack of some species of fungus. I have, however,
succeeded in placing beyond doubt the position of three aphidivo-
rous larvae, and these, with the addition of one species which I
have as yet failed to rear to maturity, comprise all which I know
to be aphis eaters.

The eggs or young grubs have been obtained in different
localities around Bath and near Radstock, Somerset, and by the
kindness of Mr. C. J. Watkins, numerous specimens have been
sent me from Pains wick, Gloucestershire. Hence the specimens
observed may be taken to be fairly representative of English
species.

A vast proportion of the larvae, wherever collected, are more
or less rough in skin, brown, or very dark grey, finely speckled
with black, sometimes beset with small spines, and having a more
or less black, or occasionally coloured, lines, visible through the
transparent outer skin, down the centre of the dorsum. These
larvae form pupa cases, of a dark grey brown, coffee brown, or
brown black, which retain the finely sprinkled black specks of the
larvae, and frequently exhibit slight oblique marks of lighter or
darker colour, together with five dark lateral spots, and in some

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. k

122 PREDACIOUS AND PARASITIC

instances a slightly marked black line along the dorsum. The fly
which emerges is invariably Syrphus luniger, and is figured on
PL XVI. of Vol. IV., together with the larva and pupa.

A larva occasionally met with, and more especially in fruit and
kitchen gardens, is, I think, smooth, save for the creases of the
skin, plump, and of the colour of parchment. It is frequently
marked with blotches, which are generally situate on either side of
the medial line of the dorsum, and which vary in colour from dull
yellow to dark brown and black. These patches are due to masses
of pigment underneath the skin, through which they are visible.
The pupa-case is similarly parchment-like in appearance, free from
speckling, and sometimes slightly ribbed, especially after the
escape of the fly, which belongs to the same genus as the last des-
cribed, though to a different species. It is Sy7'phus topiarius.

The third variety which I have succeeded in identifying is a
smooth skinned grub, far from common, of a pale green colour,
and having a more or less marked stripe of pink or carmine down
the centre of the back. This larva eventually produces the fly,
Caiabomba pyrastri.

Besides these, I have made repeated attempts to rear an aphi-
divorous larva, small, greenish, or grey in colour, nearly or quite
smooth, with very delicate markings, and generally having fine
lines of light carmine on the dorsum and around the lateral edges.
These larvae habitually undergo long fasts and periods of inactivity,
and the specimens which I have succeeded in keeping alive for
several months have in each instance succumbed to the attacks of
a fungoid growth, which seems to affect the mouth parts. But I
have also reason to think that the larva of Flatychirus albimanus
is aphidivorous in its habit, and if so, it would seem to me to be
exceedingly probable that the larva last described belongs to that
species.

It is impossible to say, from only a few seasons' experience of
the counties of Somerset and Gloucester, whether all the aphidi-
vorous varieties have been observed. One, S. balteatus, is known
to be an aphis eater, and I have on one or two occasions reared it
from larvae closely resembling those of 6". luniger^ but have failed
to identify the grub from the others. The larva of S. ribesii is
also no doubt aphidivorous.

ENEMIES OF APHIDES. 123

It Qiay be said, then, with some certainty, that the following
species prey upon Aphides : — Syrphus luniger^ S. topiarius^ Cata-
tomba pyrastri, S. balteatiis, S. ribesii, and in all probability Platy-
chirus albimanus. Mr. G. B. Buckton, in his British Aphides,
mentions the genera, Sccet^a and Cheilosia^ as containing species
which are aphis eaters ; but, although I have frequently taken flies
of this genera, I have never found any of my aphis-eating larvae
develop them. This may be accounted for by the fact that many
species of insects are very local. It should perhaps be added, by
way of warning, that notwithstanding the particulars which I have
been able to give, the recognition of these larvae requires consider-
able experience, and cannot be considered as certain until the
appearance of the pupa-case fully confirms the diagnosis of the
larva.

[ now come to a very interesting point in the economy of the
Syrphidae. In the course of numerous dissections of the flies
which I have made during the past two years, my attention has
been frequently arrested by the pollen-grains which are invariably
present in all parts of the alimentary system, from the oesophagus
to the rectum, and even in the excreta.

The idea that the mouth-organs of the Diptera are only
adapted to the imbibition of fluids or juices must be considerably
modified, if it be agreed that pollen forms a considerable, if not
the greater, proportion of the food of the Syrphidae in a state of
nature. And that such is the case I am quite satisfied. My
observations of the stomachs of several species of Syrphus^ Eris-
talis, and Rhingia leave no doubt that in all these, pollen consti-
tutes the bulk of the food ingested, and it is found in the oesopha-
gus, in the sucking stomach, in the digestive stomach, and in the
alimentary canal in varying conditions, which indicate plainly the
progress of digestion.

In view of the inapplicability of the suctorial parts of the pro-
boscis to the ingestion of a solid-like pollen, this organ becomes a
fresh object of interest ; and I have endeavoured, by means of the
greatly amphfied figure on PI. VIIL, to set before the reader the
details of its structure. It will be seen that the split tubes, or
" pseudo-tracheae," take their rise on either side from a curved
chitinous channel of similar structure, into which any fluid

124 PREDACIOUS AND PARASITIC

absorbed by them would pass, and which in time would convey it
to the anterior extremity of the hollow shown at a, which consti-
tutes the floor of the mouth. In this hollow, when at rest, lie the
long lanceolate tongue (Hgula), b, and the horny upper lip, c^ both
of which are partly shown more highly magnified at Fig. 2. When
these parts are in place, the upper lip, c, constitutes, with the
bottom of the groove or hollow, «, a tubular passage, through
which fluids, absorbed by the lobes, find their way to the pharynx
and thence to the oesophagus. This passage presents ample space
for the passage of pollen-grains also ; but a comparison of the
diameter of those found in the oesophagus with the width of the
" pseudo-tracheae " of the lobes at once makes it evident that it is
not by their means that the pollen-grains reach the mouth.

An examination of the upper lip, as shown at Fig. 2, suggests
an explanation of the manner in which the ingestion takes place,
which is doubtless correct. The upper part of the extreme end is
divided into teeth, which are sufficiently wide apart to admit of
pollen passing between them; but between these are smaller
brush-like processes, which appear especially fitted to sweep
it from the flowers upon which the fly feeds into the cavity of the
mouth, where it is met by the secretion issuing from the duct,
which proceeds from the salivary glands, and which terminates in
the tongue. This duct is shown on Fig. i, at j".

The uniformity with which the pollen-grains are to be found in
all parts of the alimentary system, and their great abundance in
the sucking stomach, indicate pretty clearly the important share
they take in nutrition. To assure myself more fully of this, I have
experimented by supplying the flies, both reared and captured,
with saccharine foods. The flies were kept under the most natu-
ral conditions consistent with confinement. They at first attacked
the food with avidity, but although fresh leaves, etc., were given
daily they soon became languid and generally died about the fifth
or sixth day. On examination of a fly under these conditions, the
sucking stomach is invariably found full of a clear syrupy fluid,
while the proper stomach and intestines appear collapsed and
empty. It seems probable that, as in the human stomach, the
presence of more or less solids is an important factor in stimulat-
ing the digestive organs into action. Possibly, the effect of the

ENEMIES OF APHIDES. 125

cellulose cases of the pollen may be somewhat similar to that of
the bran of brown bread or the husks of oatmeal when either of
these are ingested by man.

Mr. J. W. Morris, F.L.S., has kindly endeavoured to identify
for me the pollens found in the viscera of Syrphus luniger, Rhingia
rostrata, and Erisialis tenax, and the result is, I think, a very
remarkable addition to our stock of knowledge in this direction.
These three species differ materially from one another in their
characters and habits, and the specimens examined were taken on
hedgerows or in gardens some miles apart. But two pollens were
found always present, accompanied by a third in a few instances
and in small numbers. The difference in appearance which may
be due to the liquids of the stomach necessarily makes precise
recognition difficult, if not impossible, and I think, myself, that
there is room to doubt whether this apparent third variety may not
be the result of partial digestion. At any rate, no more than three
pollens at the most are found, two of which are, without much
doubt, the pollen of some species of Doronicum^ or " Leopard's
bane,'" varieties of which bloom from spring to autumn, and that
of some near allies of Lathy rus^ of which the Everlasting Pea and
the Bitter Vetch are examples. These are shown at Fig. 3 on
PI. VIII., together with the other variety.

As the flies visit in succession numerous flowers apparently for
food, it would seem that from among them all they select the
pollen of these or of nearly allied species, thus exercising a dis-
criminatory power which I am not aware has been similarly
observed among winged insects, and which, when confirmed by
other observers, will add to our estimate of the high degree of
intelligence already claimed by naturaUsts for the Insecta.

The fact that the outer shells of these minute grains pass
through the fly in so perfect a condition as often to present no
serious difficulty in their identification, raises some interesting
questions as to the nature, the process, and the secretions by which
digestion is accomplished. In order to study this, it will be desir-
able for a moment to consider the composition of pollen.

The grains of pollen consist of an outer case of considerable
hardness, which appears to be mainly cellulose, and which con-
tains the protoplasmic mass known as "foyilla." The hard case

126 PREDACIOUS AND PARASITIC

presents some points, which are capable of being ruptured by the
expanding fovilla, which, if it has the opportunity, penetrates, by
means of an extension, known as a ^'-pollen tube," the stigma of a
flower of its own kind, and effects the fertihsation of the ovules
contained in the ovary at the base of the style.

From these circumstances we might expect that the semi-fluid
contents of the pollen grains would be of a highly nitrogenous
character, and would possibly contain also such elements as phos-
phorus and sulphur.

The following analysis of " Pollen," by Schneider, given in the
Journal of the Chem. Soc, Vol. X., p. 175, shows that this expecta-
tion is well founded.

Water

Ash, chiefly Phosphates ...

Albumin and Peptones ...

Sugar

Fats and Fatty Acids (colouring matter)

Cell Membrane

Pecten

99-86

Sachs states that fovilla consists of " coarse-grained protoplasm,
with grains of starch and drops of oil." Another authority states
that it consists of " starch granules, oil globules, and protein com-
pounds." From my own experience, I am inclined to think that
the sugar given in the above analysis should have been shown as
its equivalent of starch, from which it was probably formed in the
analytical process. The proteids are mainly, if not wholly, in the
form of albuminoids, and do not differ widely from the following
analyses of vegetable albuminoids, given by Lintner and Szilagyi
respectively : —

Carbon .. 43-33 ... 44-50

Hydrogen ... 6-98 ... 7-08

29-89

3-08

17-81

25-12

8-98

7*56

7-42

Nitrogen
Sulphur
Oxygen
Ash

9-92 ... 9-49

1-07 ... I -08

32-91 ... 32-95

479 ••• 4"9

ENEMIES OF APHIDES. 127

Now, the percentage of nitrogen in beef is stated by Dr.
Letheby at ten, and Professor Goodfellow tells us that it is in the
form of albuminoids, which constitute fifteen per cent, of the
whole bulk. And very little difference exists in the composition
of albuminoids, whether they are derived from an animal or vege-
table source. We have seen that pollen contains some 17 or 18
per cent, of these compounds of nitrogen. But although nitrogen
is one of ihe most necessary constituents of animal food, and is
generally ingested in the form of albuminoids, yet as such, it is
incapable of assimilation, because albuminoids are incapable of
undergoing diffusion through animal membrane. Hence, it is
necessary for them to undergo some change which shall render
them diftusable, and in man this is accomplished by the first secre-
tion which the food meets in the stomach — that known as the
" gastric juice." Under the influence of certain constituents of
this secretion, the albuminoids are converted into " peptones,"
which, while possessing a similar composition to albuminoids, are
highly diifusable, and are capable of readily passing through animal
membrane. The process is somewhat as follows : — When food
enters the human stomach, it sets up a nervous disturbance, which
causes the walls to become suffused with blood, and under the
influence of the stimulation thus applied, the gastric glands pour
out their secretion to effect the necessary change.

In the Syrphus fly the similarly constituted food, on being
impelled from the extension of the oesophagus, known as the
sucking stomach, enters the proventriculus, which forms the
entrance to the proper or digestive stomach. Here it meets with
the secretion of the adjacent glands, shown on PI. 1V„ Vol. V.,
at «, 71^ which appear to be brought into action by the presence of
hard food in the proventriculus, and following on this the changed
appearance of the pollen makes it clear that the digestive process
has begun. For comparison a gastric gland from the human
stomach is depicted on PI. VHI. at Fig. 4, and it will be seen that
it presents considerable analogy to the apparently similar gland of
the fly.

On these grounds, therefore, it seems not unwarrantable to
assume that the secretion of the glands {n, n), which is the first
digestive fluid encountered, apart from the saliva, answers much

128 PREDACIOUS AND PARASITIC

the same purpose as the gastric juice in man, and I think we may
fairly describe these glands as "gastric glands."

The investigation of the means by which the oil-globules of the
fovilla are rendered available for the nutrition of the insect presents
great difficulty, inasmuch as no organ presents itself as likely to
exercise pancreatic functions, and as yet I have failed to observe
the point at which the oily globules of the pollen disappear.

Another interesting set of organs, which are remarkably well
seen in many of the Syrphidae, are those which I shall call the
"renal bodies." They are shown on PI. IX. both in situ, in
Fig. I, and under a higher amplification the individual organs are
depicted at Figs. 2 and 3, as seen on the surface and in section.
These are from Syrphiis luniger, but Fig. 4 (shown in situ in the
wall of the rectum) is from Eristalis tenax^ and with it are shown
some of the smaller pollen-grains (Lathyrus) floating loose in the
rectal cavity. These organs are also indicated on PI. IV., Vol. 5,
at /, t. These organs, which perform somewhat similar excretory
functions to the kidneys of animals, are four in number, and are
inserted through the walls of the rectum at a point below the valve,
at the termination of the lower intestine, where the former
enlarges to form a lemon-shaped pouch.

The arrangement and construction of these organs are obvious
from the drawings. Each one of the conical bodies consists of a
hollow cone, composed outwardly of a delicate membranous
sheath, beneath which a thick layer of gland-cells are disposed.
These are somewhat angular from mutual pressure, and each
contains a nucleus, which, however, is generally very difficult to
demonstrate.

The gland-cells are supported by a transparent and apparently
structureless membrane, which forms the inner surface of the cone.
A plentiful supply of oxygen is ensured by the large and direct
tracheal trunks, which connect these organs with the spiracles of
the abdomen. These trunks do not appear, as in the Musca vomi-
toria^ to divide into distinct sets of vessels supplying respectively
the inner and outer layers of the organ, but branch off in a tree-like
fashion, as shown in Fig. 3, ultimately ramifying into fine tubes,
which are disposed parallel to the exterior surfaces, beneath the
outer membrane, through which they may be seen by careful
focussing, as in Fig. 2.

ENEMIES OF APHIDES. 129

The inner surface of these organs appears to be in free con-
nection, and in fact continuous with, the cavity of the abdomen,
the fluids of which are no doubt pressed into them during the
alternate compression and dilation which the abdomen of the fly
continually exhibits. It is probable that they contract and expel
the fluid by means of muscular bands at their bases, which are not
shown in the drawings. Thus, a continual passage of the abdo-
minal fluids would give opportunity for the secretory glands to do
their work. This appears to be the separation of urinary com-
pounds, and may, under favourable circumstances, be evidenced
by the demonstration of the presence of uric acid in the rectum,
while it cannot be found above the valve connecting it with the
intestine. The presence of uric acid in the excreta may be readily
shown by acidulating it on a slide with a minute quantity of hydro-
chloric acid, when crystals of uric acid will be readily formed.
Indeed, the first white excreta passed by the fly after its emergence
from the pupa-case is almost entirely uric acid.

The only remaining feature which I propose to notice here is
the three spermathecae, with their extraordinarily long and slender
seminal canal, which, if extended in a direct line, would measure
about "25 inch in Eristalis tenax, the species in which it can be
dissected out with least difficulty. One of these receptacles is
shown with the attached tube on PI. VIII., Fig. 5. It consists of
a dark brown, opaque, chitinous capsule, nearly spherical in shape
when fully expanded, and formed of two or three segments, in
some way jointed together. Each receptacle is surrounded by a
layer of cells, which are covered by a more or less wrinkled mem-
brane, probably containing muscular fibres. When the female is
yet unmated, the spermathecse present the appearance of two
flattened capsules, placed edge to edge, from one of which pro-
ceeds the immensely extended narrow canal connecting it with the
vagina. Around the opposite capsule is a considerable mass of
what appears to be cellular tissue interspersed with muscular
fibres, and which, when the capsules expand to a spherical form on
the entrance of the spermatic fluid, appears to stretch so as to form
an even covering. The earlier condition is shown at Fig. 6 on
PI. VIII. ; the later state at Fig. 5, where also are shown the thin
delicate tubes, which form the passage for the spermatozoa. These

130 PREDACIOUS AND PARASITIC

tubes are encased in tissue similar to that enveloping the sperma-
thecse themselves, and their inner coat is continuous with that of
the interior of the capsules. The latter are lined with epitheHal
cells of an angular form and of a dark brown colour, which may
readily be seen on breaking the capsule by a little pressure on the
cover-glass, when also the junctions of the edges of the capsules
will often be evident. The three spermathecae are in some species
grouped together in a surrounding membranous network ; but in
some, as Syrphus luniger, they are arranged two on one side and
one on the other, as in the Blow-Fly.

The Classification of the Syrphid^.

It has already been mentioned that this family has been divided
by entomologists into something like forty genera, which are
inhabitants of Britain. But this has not been accomplished
without vast labour and an immense number of changes in the
arrangement. Over and over again, by Fabricius, Meignen,
Walker, Fallen, and others, genera have been constituted, recon-
stituted, and abandoned, and, not uncommonly, so complete has
been the change that the generic names seem to have been trans-
ferred from one group of species to another.

I do not propose to enter upon an examination of the whole
of this extensive family. Such a course would be beyond the
scope of the present work, but it may be useful to students of the
Aphididae if I quote from the admirable List of British Diptera,
arranged by Mr. G. H. Verrall, the particulars of those genera in
which aphidivorous larvae are most likely to occur.

The earliest writer to attempt any division of the family was
Harris, who, writing a few years after Scopoli had separated the
Syrphidce from the Linnaean genus, Musca, constituted three chief
divisions based upon the distinctive wing-neuration, as shown in
Vol. IV. on PI, XVI., Figs. lo, ii, and 12. Although this divi-
sion has not been adopted by later writers, it is convenient for the
purpose of dividing the family into sections, and I have found it
useful to group it under the heads Syrphidince (Fig. 12), Eristalince
(Fig. 11), and VolucellidcB (Fig. 10).

Donovan gave some illustrations of this family at the end of
the last century, and between 1825 and 1840 J. Curtis published

ENEMIES OF APHIDES.

131

several very beautiful and exact coloured plates of various species,
with many descriptions. His plates usually represent the rare
rather than the ordinary varieties, and thus their value to the
student is for special rather than everyday studies. They are,
however, almost unequalled for accuracy of drawing and delicacy
of colouring. Many of the generic and specific descriptions have
been since abandoned.

Some fifteen years later Walker described the family among his
Diptera, but added little to our information concerning it. Schiner
and Meignen have written with authority on the Diptera of Europe,
and the works of both, published in German, are standard. In
1864 the former proposed some extensive changes in the arrange-
ment of this order, and a few years later Osten-Sacken produced
his classification.

At present Mr. Verrall's lists of Diptera are our best authority
as regards the family of Syrphidce, and I take the following list of
genera and species from his issue of 1888, adding to the latter,
by the kindness of Mr. C. J. Watkins, a few species which have
been noted since. These are italicised, while the known aphidi-
vorous specimens are starred.

Genera comprised in the Family Syrphid^,

from Mr. G. H. Verrall's list of British Diptera, published in 1888 :

Number of Number of

Genus. ^ Species. Genus. Species.

1 Paragus (Lat.) ... 2 12 Didea (Macq.) ... i

I species added since i888

2 Pipizella (Rud.)

3 Pipiza (Fin.)

4 Cnemodon (Egg.)

5 Orthoneura JMacq.) ..

6 Chrysogaster (Mg.)

7 Chilosia (Mg.)

I species added since 1888.

8 Leucozona (Schin.)

9 Melanostoma (Schin.) ..

10 Pyrophoena (Schin.) ..

11 Platychirus (St. Farg.) .,

I species added since 1888.

13 Syrphus (Fab.)

34

3

Several species added since 1888

5

14 Catabomba (O.-Sack)

2

I

15 Telecocera (Mg.)

I

3

16 Sphserophoria (St. Farg.)

6

8

17 Xanthogramma (Schin.).

2

26

18 Doros (Mg.)

2

19 Myiolepta (Newm.) ..

I

I

20 Baccha (Fabr.)

I

6

2 1 Sphegnia (Mg.)

I

2

22 Ascia (Mg.) ...

2

12

23 Rhingia (Scop.)

I

24 Brachyopa (Mg.)

I

132

PREDACIOUS AND PARASITIC

Genus.

25 Volucella (Geoff.)

26 Sericomyia (Mg.)

27 Arctophila (Schin.)

28 Eristalis (Latr.)

29 Myatropa (Reid)

30 Helophilus (Mg.)

31 Merodon (Mg.)

32 Tropidia (Mg.)

33 Criorrhina (Macq.)

34 Pocota (St. Farg.)

Number of
Species. Genus.

Number of
Species.

4 35 Brachypalpus (Macq.)
2 36 Xylota (Mg.)

I 37 Syritta (St. Farg.)

10 38 Eumerus (Mg.)

I 39 Chrysochlamys (Reed)

9 40 Spilomyia (Mg.)

I 41 Chrysotoxum (Mg.)

I 42 Callicera (Fab.)

5 43 Microdon (Mg.)

7
I

3
2

2

7
I

The following Genera comprise those which contain species known
or believed to be aphidivorous in the larval state :

Chilosia (Meignen).
(Some larvae said to be aphidivorous.)
maculata, Fin.
antiqua, Mg.
sparsa, L. W.
pubera, Ztt.
soror, Ztt.
scutellata, Fin.
longula, Ztt.
pulcripes, L. W.
praecox, Ztt.
vernalis, Fin.
nebulosa, Ver.
chloris, Mg.
grossa, Fin.
chrysocoma, Mg.
flavicornis, F.
mutabilis, Fin.
fiavimana, Mg.
albitarsis, Mg.
impressa, L. W.
rostrata, Ztt.
variabilis, Pz.

CH I Losi A — continued.
barbata, L. W.
vulpina, Mg.
olivacea, Ztt.
intonsa, L. W.
oestracea, L.
plumuHfera, L. W.
Syrphus (Fabr.)
Several larvae known to be aphidivorous.

barbifrons, Fin.
lasiopthalmus, Ztt.
punctulatus, Ver.
umbellatarum, F.
compositarum, Ver.
flavifrons, Ver,
decorus, Mg.
auricoUis, Mg.
cinctellus, Ztt.
cinctus, Fin.
*balteatus, De G.
bifasciatus, F.
arcuatus, Fin.
lapponicus, Ztt.

ENEMIES OF APHIDES.

133

SYRPHUS — continued.
*luniger, Mg.
corollae, F.
annulatus, Ztt.
vittiger, Ztt.
latifasciatus, Mag.
nigritarsis, Ztt. ?
nitens, Ztt. ?
nitidicollis, Mg.
vitripennis, Mg.
* ribesii, L.
diaphanus, Ztt.
grossulariae, Mg.
*topiarius, Mg.
tricinctus, Fin.
Venustus, Mg.
lunulatus, Mg.
quadrilunulatus, Schum.
albostriatus, Fin.
laternarius, Miill.
glaucius, L.
guttatus, Fall.
arcticus, Ztt.
triangulifer^ TAX.,
anmdipes, Ztt.
lineola, Ztt.

Catabomba (Ost. Sack.)
*pyrastri, L.
selenitica, Mg.
Sph^ophoria (Scseva).
(St. Farg.)
(Some larvoe said to be aphidivorous

scripta, L.
dispar, L. W.
strigata, Staeg.

SPH.EOPHORIA — continued.
picta, Mg.
menthastri, L.
nitidicollis, Ztt.
Pelecocera (Meigen).
(Larva possibly aphidivorous.)

tricincta, Mg.
Platychirus (St. Farg.)

manicatus, Mg.

melanopsis, L. W.
*albimanus, F.

latimanus, Whlbg.

peltatus, Mg.

scutatus, Mg.

fulviventris, Macq.

immarginatuSj Ztt.

scambus, Staeg.

podagratus, Ztt.

clypeatus, Mg.

angustatus, Ztt.

spathulaiuSy Rud.
Pyroph^na (Schiner.)

(Larvae possibly aphidivorous.)

ocymi, F.
rosarum, F.
Leucozona (Schiner).
(Larvse possibly aphidivorous,)

lucorum, L.
Melanostoma (Schiner).
Quadrimaculatum, Ver.
ambiguum, Fin.
) dubium, Ztt.

scalare, F.
mellinum, L.
hyalinatum, Fin.

134 ENEMIES OF APHIDES.

EXPLANATION OF PLATES YIII. and IX.

Plate VIIL

Fig. 1. — Proboscis of Syrphus luniger seen obliquely, and having the
near labial palpus removed : — a, The bottom of the mouth ;
6, the tongue (ligula) ; c, the horny upper lip ; k, k, the lobes
of the under lip ; s, the salivary duct.

2. — Enlarged view of the extremity of the upper lip, showing the
teeth and spiny processes. Below is shown the extremity of
the tongue.

3. — Pollens from the oesophagus, stomach, and rectum of Rhingia,
Syrphus, and EHstalis.

4. — Gastric gland from human stomach.

5. — Spermathecse and spermatic canals from female Eristalis tenax

6. — One of the spermathecpe of Eristalis before expansion, show-
ing the separate capsules and the enveloping membrane.

Plate IX.

Fig. 1. — The renal organs of S. luniger, in situ, in the expansion of
the rectum, showing their insertion through the partially
transparent walls of the rectum and the distribution of the
tracheal trunks.

2. — One of the papillae removed and carefully focussed for the
underside of the outer membrane, so as to exhibit the termi-
nation of the tracheal branches.

3. — The same, seen in section.

4. — One of the papillae of Eristalis tenax, seen in situ, displaying
the arrangemeut of the tracheal tubes and the internal cavity.
Pollen-grains are seen floating free in the rectum.

»>

> >

The question whether the intensity of the radiation of heat by
the sun is affected by its condition as to spots has been studied
by M. R. Savelief, of Kiev, in the light of observations made in
the spring and the fall of the years 1890, 1891, and 1892. The
results point to an affirmative answer, the radiation being greater
as the sun-spot activity augments. A variation in one series of the
experiments is interpreted as indicating that the increase is
dependent, not so much on the absolute number of the spots as
upon the intensity of their evolution ; or it may mean that it is
immediately consecutive on their diminution. — Pop. Set. Mon.

Journal of Microscopy N, S. Vol. 5. PI. 8

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// C.A. V/'n e,ac( na/' c^e/.

F PhW/ps Sc.

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Journal of Microscopy N.S. Vol. 5. PI 9

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F. Phillips Sc.

[ 135 ]

BenbanVe '' artificial Spectrum Zo\?:'

By G. H. Bryan, M.A.

IT is well known that if a circular disc of cardboard is painted
in sectors with the different colours of the spectrum, and is
made to spin rapidly as a top or " tee-to-tum," the disc
appears white in consequence of the impressions produced by the
various colours on the retina remaining behind for a short time
and so mixing together. But that the opposite effect can be pro-
duced— namely, that of seeing colours on a rapidly revolving top
where no colours really exist — is a discovery that one would hardly
have expected. Yet such is the result accomplished in the latest
optical novelty, invented by Mr. C. E. Benham, and sold by
Messrs. Newton and Co. under the name of "The Artificial
Spectrum Top."

Fig. 5.
The top consists of a cardboard disc, one half of which is
black, while the other is white, with a number of circular arcs of
black projecting into it on either side, and subtending an angle of
about 45 '^ at the centre. The arrangement of these arcs is imma-
terial, provided that the arcs on one side of the centre are arranged
not to clash with those on the other, and a possible arrangement
is shown in Fig. 5. -When such a disc is mounted on a peg as a
top and spun, or carefully centred on a microscopist^s turn-table
and rotated in a bright light, the various arcs will produce the
appearance of rings, and these rings will appear coloured. If the
disc is rotated in the direction of the hands of a clock (as will be

136 benham's artificial spectrum top.

the case when the top is spun in the ordinary way between the
thumb and finger of the right hand), the arcs along the portion
AC will produce rings more or less blue, or at any rate fringed
with blue, and those along CB will produce rings more or less red
or fringed with red, and in some parts the background will be of a
more or less greenish tint. Thus, with the arrangement shown in
the figure, we shall see two blue rings inside, followed by three red
rings, and lastly two blue rings outside all.

If, however, the disc is spun in the opposite direction (as will
be the case when it is attached to a turn-table and spun by the
left hand) the colours will be reversed, the arcs along AC produc-
ing red rings, while the arcs along CB produce blue rings; the
blue will, therefore, now be intermediate between the inside and
outside red rings. In the top, manufactured by Messrs. N'ewton
and Co., there are twelve arcs, arranged in batches of three on one
side of the centre and then three on the other, producing alternate
groups of three red and three blue concentric rings. As a rule,
the best effects are obtained by revolving the disc in a bright light
and the colours seen depend on the rate of rotation, being usually
brightest when the disc is rotating as slowly as is. consistent with
the markings, appearing blurred into continuous rings.

A series of investigations on these appearances has been made
by Prof G. D. Liveing, of Cambridge, who has also constructed a
variety of discs with figures in black disposed on a white ground
and with white figures on a black ground. All of these, when
revolved in a bright light, show remarkable bands of colour of
various shades of red, green, and blue. The general result of his
observations of these discs is that if a succession of black and
white objects are presented to the eye with moderate, but not too
great, rapidity, then, when black is followed by white, an impres-
sion of a more or less red colour is perceived, while when white is
succeeded by black a more or less blue colour is perceived. If
the succession of black and white is very rapid, the appearance
presented to the eye is of a more or less neutral green or drab.

For different people the rate of rotation necessary to produce
the impression of a particular tint varies somewhat. When excen-
tric or spiral bands of black are used, the impression on the eye
is that of fringed bands, reddish on one side and greenish on the

benham's artificial spectrum top. 137

other. Sometimes the coloured bands seem mottled or the colours
appear in flashes radiating from the centre of revolution.

Prof. Liveing is not at all satisfied with the explanation pub-
lished by Mr. Benham, which is to the effect that the average
number per second of stimuli affecting tlie eye is increased, or
diminished, according as a black portion of a band follows or pre-
cedes a white ground, in the revolution of the disc.

The only explanation Prof. Liveing can himself offer is based,
firstly, on the known facts that the impression produced on the
retina by a bright object remains for an appreciable time after the
light from the object has been cut off, and that the duration of
that impression is different for different colours (a result discovered
by the late eminent physicist and physiologist. Von Helmholtz) ;
and secondly, on a supposition (which he does not know to have
been as yet verified experimentally) that the rapidity with which
the eye perceives colours is greater for one end of the spectrum
than for the other. From this point of view, the explanation of
the blue colour seen when white is followed by black would be
that the impression of blue on the retina lasts a little longer than
that of the other colours ; while the red colour seen when white
succeeds black is due to the greater rapidity with which the eye
perceives red light than that with which it perceives blue.

If, however, the alternations of white and black succeed each
other with sufficient rapidity, the new impression of a white patch
will be produced before that of its predecessor has vanished, and
there will be an overlapping of impressions, and the sensation will
be that of a mixture of colours of a more or less neutral tint.
This is in accordance with the observation that if several circular
bands, each partly black and partly white, in equal proportion, are
on the same disc ; but in some of the bands the whole of the
black parts is in one patch, while in others it is divided up into
several patches, then, when the disc is rotated so that the band
which presents only two alternations at each revolution is seen
coloured, the bands which present a greater number of alternations
are seen of a neutral tint. Also, if the rotation is rapid enough,
the bands all appear of a neutral tint.

So far as he can test the theory by his own eyes, it appears to

Prof. Liveing that the residual impression, left when the light from

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. l

138 benham's artificial spectrum top.

a white object is suddenly cut off, is at first green and fades out
through a more or less blue or slate colour. The object must not,
however, be so bright as to dazzle the eye, as the duration and
colour of the residual impression might in that case be very differ-
ent. Prof Liveing sees the colours of the discs best in bright
diffuse daylight, and sees hardly any colour when the discs are in
direct sunshine, but no two observers see the same appearances
under the same circumstances.

The discs used in most of Prof Liveing's experiments, and
Messrs. Newton's top, are about six inches to a foot in diameter ;
but the size is unimportant, and the small sketch from which the
present figure was drawn, when placed on a turn-table, exhibited
colours equally bright to those on the larger tops.* The black
parts may either be painted on the top or made of pieces of dead-
black paper, and Prof Liveing used a kind of black paper, which
he finds to be a perfect absorbent of light of all colours, thus
effectually disposing of any questions as to whether the appear-
ances may be due to colours actually present in the black or white
parts of the disc.

The experiments may be varied by making the top with white
arcs projecting into the black portion, and they will supply much
material for recreation on a dull winter's evening, when bright
gas or lamplight will answer admirably.

* If, however, the top is too small and light, it cannot be made to spin
slowly enough to show the colours well, M'hile too large and heavy a top is
difficult to set spinning sufficiently rapidly.

With reference to Crolls and Ball's theories of ice ages and
genial ages, Mr. Edward P. Culverwell has shown, on the basis of
calculations of the daily distribution of solar heat on difterent
latitudes at the present time and in the supposed glacial and genial
ages, that the winter temperature of Great Britain in the glacial age,
as dependent on sun heat, would be no lower than that from
Yorkshire to the Shetlands ; and similarly that, from 40'^ to 8o^of
north latitude, the shift of the winter isothermals would be only
about 4^ of latitude, a result wholly inadequate to produce an ice
age. The shift of isothermals in the genial age was found to be
much smaller. — Popular Science Mo7ithly.

[ 139 ]

a few Ipointe in connection witb
tbc pb^aiolog^ of tbe Special Seneee.

By Arthur J. Hall, B.A., M.B. Cantab., M.R.C.P.,
Lecturer on Physiology at the Sheffield School of Medicine.
(Being the Presidential Address delivered before the Sheffield Micro-
scopical Society at the opening of the Session 1894 — 5.^

1HAVE selected as my subject for this evening The Special
Senses, in the hope that there may be something about them
which you may not all have heard before, and even if you
have, may yet bear repetition. Man is usually said to be endowed
with five special senses — Sight, Hearing, Taste, Smell, and Touch.
Let us first enquire what that means. In the two former lectures*
I have had the honour of giving you, I have insisted at some
length on the fact that a living organism such as man is really an
enormous colony of separate living microscopic cells, which work
together in different departments for the common good. Each
little mass of living substance or cell lives its own life ; but in
doing so depends on all the other cells for their assistance, and in
turn must do its quotum for the general welfare of the whole. And
as there can never be a harmonious co-operation of individuals
unless there is some recognised superintendent, or master, or head,
so in this colony we have a special group of cells to which this
duty is assigned — namely, the Nerve-cells, making up the brain
and spinal cord, or what we call the Central Nervous System.
These cells, which compose our Central Nervous System, alone
have the property of consciousness and the power of producing
conscious effects when stimulated in various ways. It is of the
highest importance that such valuable cells as these should not be
exposed to injury from without, just as it is important that an
army in battle should not lose its commander. And so we find
the Nerve-cells forming the brain and its accessories enclosed in a
hard, bony case — namely, the skull and vertebral column. But
this very enclosure of our only conscious cells removes them at
once from the very position they should hold if they are to be
conscious of what is going on around — namely, the surface of the

*See this Journal, Vol. III., p. 257 j and Vol. IV., p. 225.

140

A. FEW POINTS IX CONNECTION WITH

body. How, then, can they be of any use to the organism as
regards obtaining food for it, directing its movements, avoiding
dangers, etc., situated, as they are, in a strong, dark, bony case, in
the most protected of all parts of the body? To understand this,
we must revert for a few moments to the study of embryology or
the development of the body. Every human being begins life as
a single, round, nucleated cell (Fig. 6, A), measuring not 2 mm. in
diameter ; and this cell must be endowed with all the living pro-
perties of the future adult body in a primitive condition, for from

Fig. 6. — Em bryological changes in Epiblast Cells, showing development
of Central Nervous System from surface cells (diagrammatic).

A, Ovum. £, C, D, Segmentation or multiplication of cells.
E, Surface layer or Epiblast. F, Dipping down of E to form Central
Nervous System. G, Tube of Epiblast, cut off. H, Diagram of con-
nection in adult between brain-cells and surface-cells by nerve-fibres.

it all the other cells are formed. It soon divides and multiplies
(Fig. 6, B and C) till the single cell becomes a mass of cells like
a mulberry (Fig. 6, D) in appearance.

THE PHYSIOLOGY OF THE SPECIAL SENSES. 141

A little later these cells begin to arrange themselves in groups,
and, neglecting the rest for our present purpose, we will confine
our attention to those on the surface of the sphere. They are
called the epiblastic cells, and form the surface of the organism
(Fig. 6, E). A certain number of these, having a definite posi-
tion, now begin to fold themselves inwards (Fig. 6, F), and finally
to become detached from the rest of the epiblastic cells (Fig. 6, G),
which close over them, leaving them inside as a ring of epiblast
cells. This ring of epiblast cells (which were once surface cells)
represents the cells from which the future nerve-cells will be
formed, whilst the rest of the epiblast gives rise to the surface-cells
of the adult body, which we call the epidermis, or skin. So, you
see, the antecedents of the brain and spinal cord cells were origin-
ally surface cells, and occupied the same position that the cells
forming the skin do now. By means of long filamentous pro-
cesses, which we call nerves, proceeding from the cells of the
Central Nervous System, these brain-cells join themselves to the
surface or epithelial cells (Fig. 6, H). In this way the central cells
can be informed, by a sort of telegraphic system, with what is
going on at the surface of the body. Thus, what we call our
special senses are nothing more than conscious impressions pro-
duced in the cells of our brains by the various external stimuli
acting upon the non-conscious cells of our surface and conveyed
up to the brain along the nerve-fibres.

And this is true of all our different so-called Special Senses.
They all require for their carrying out efficiently a surface cell or
cells, a nerve-fibre, and a brain-cell intact. If any one of these is
destroyed, the power of receiving outside impressions accurately is
lost. The eye, the ear, the inside of the nose, and the mouth are
merely modifications and elaborations of these elementary nerve-
epithelium continuations, adapted to receiving particular kinds of
impressions or stimuli only, whereas the whole of the rest of the
body surface receives simpler and less elaborate stimuli. The
waves of radiant heat from the sun stimulate the epithelial cells of
the whole surface of the body, producing a sensation of heat ; the
same rays, or very closely allied ones, stimulate the epithefial cells
of the eye and produce a sensation of light.

The waves of sound produced by a heavy cart passing in the

142 A FEW POINTS IN CONNECTION WWH

Street produce in the epithelial cells of the ear a sense of noise ;
but they also produce on the body surface a sense of vibration,
transmitted through the earth. Thus, the sense of sight, hearing,
smell, taste, and touch are merely modifications of consciousness
propagated in different ways around us, capable of being received
only by certain portions of our surface, and each producing a par-
ticular impression when the stimulus is carried up by the nerves to
our brain-cells. And the converse also holds good — namely, that
in whatever way those surface-cells are stimulated, the cerebral
impression called forth is the one that would be called forth by
the usual stimulus affecting them. For example, a blow on the
eye produces the sensation in the brain-cells of a flash of light,
because the central cells merely receive a stimulus from the eye
epithelium, and that is usually due to waves of light. So also in
disease, when the surface epithelium is being constantly irritated,
there may be, if it is in the ear, noises ; if in the eyes, flashes of
light ; or if in the skin, creeping sensations ; and so forth.

I would next draw your attention to the accuracy of the locali-
sation of stimuli on the body surface. Although the seat of the
conscious impression is enclosed in the bony skull (and we know
that it is so because during sleep, or brain rest, the external
stimuli produce no effect); yet when an external stimulus acts upon
any part of our surface, the brain-cell not only receives an impres-
sion of surface irritation, but we know exactly where on the body
surface the irritation has occurred. Thus, if something touches
my little finger, I immediately know the exact spot where my
finger has been touched, so that I am able at once, if necessary,
to move my muscles so as to remove the irritant if it be harmful,
or to seize it if it is wanted. There must, therefore, be somewhere
in the brain a separate set of nerve-cells representing each square
inch of the body surface ; and whenever those are irritated the
consciousness projects the impression to its corresponding portion
of surface ; something in the way, that if the little brass plate
opposite my number in the switch-room of the Central Telephone
Office drops, the attendant thinks I have rung, and calls out to
know if I am there. Usually 1 have rung ; but if there is some
fault in the little brass plate and it falls of itself, the resulting
impression on the attendant is the same.

THE PHYSIOLOGY OF THE SPECIAL SENSES. 143

So in our bodies. If the central nerve-cells are themselves
diseased and irritated, the impression on the brain is projected on
to some external surface change ; and in such a way people who
are insane see, hear, and feel things around them which do not
exist except to themselves, but they see and hear them very really.

Now, this perfect localisation of sensations is not equally
present in all of us at all periods of our lives. It is partly the
result of past impressions, memory, and partly the combined
result of using all our senses together. By education or training,
the senses can be made much more acute ; that is, the power of
localisation can be made more accurate, and not only that, but a
slight stimulus applied to the surface can be much more fully
interpreted by comparing it with previous stimuli like it.

Let us take, for example, the neuro-epithelial mechanism of
the skin, which, we say, is endowed with the sense of Touch.
This sense of Touch is in reality at least threefold. There is the
Tactile sense, or sense of Touch proper, and the sense of Tem-
perature, together with something quite different — namely, the
sense of Pain, though this sense of pain is unfortunately not
Hmited to the surface of the skin. That these three are quite
distinct from one another, and travel by different nerve-fibres to
the brain, is undoubted, for in certain not uncommon diseases of
the nervous system the sense of pain may be altogether absent,
whilst the senses of touch and temperature remain. Thus, the
person can feel anything touching him, can tell a warm body from
a cold ; but if pinched or pricked with a pin, feels no pain what-
ever, but merely feels the contact of the pin touching him. So
also in other cases, the person can tell hot from cold, but cannot
feel the contact of the hot or cold body.

The different parts of the surface of the body differ very
greatly in their power of dehcately appreciating touch and
temperature, and those parts which are most sensitive to touch are
not the most sensitive to temperature. There is a simple instru-
ment called an yEsthesiometer, by which the tactile sensibility of
different parts of the surface may be readily estimated. It consists
of two fine points, which can be brought close together or sepa-
rated by a sliding scale, so that the distance between them can
easily be read off. The points are then laid on the skin and

144 A FEW POINTS IN CONNECTION WITH

placed closer and closer to one another until they can no longer
be distinguished as two distinct points. The seat of most acute
tactile sensation is the tip of the tongue, where two points, only
I mm. apart, may be distinguished. Next comes the inside of the
finger-tips, where, at 2 mm. apart, they are felt distinct ; whilst on
the back of the hand they are only distinguished as two when
30 mm. apart ; and on the neck and back of the trunk when from
50 — 70 mm. distant.

The Temperature sense is somewhat more complicated to
investigate, inasmuch as some parts of the skin seem to feel low
temperature more readily, and some to feel high temperature more
acutely ; but, speaking broadly, the seats of most acute tactile
sensibility do not correspond to those of most acute temperature
sense. For instance, the shoulders and back are very sensitive to
changes of temperature, not of touch. I stated a short time ago
that our knowledge of our -surroundings is the combined result of
the manner in which they stimulate our various special senses,
coupled with our memory of past stimuli.

Thus, we find that whenever we see, hear, smell, taste, or touch
anything, a mental picture is produced which is far more elaborate
than the stimulus alone really warrants us in forming ; so that in
analysing our impressions we must very carefully distinguish what
we actually see, hear, smell, taste, or touch from what we think we
do. Familiar examples of this occur every moment of our lives.
We pass a cookshop and smell certain odours, and immediately
infer that certain things are being cooked, from our previous expe-
rience. We see the rays of light from this table with certain
shadowed and bright lines, and infer that the table is made of
wood covered with leather and solid. But the actual rays which
are stimulating our eyes do not carry any such information them-
selves, so that a clever drawing of a table might entirely deceive
us.

Now, this distinction between what we really see, to take this
sense for our example, and what we think we see, which is a
process of cerebration, comes home very strongly to all who take
up microscopy; for in microscopy the size of the objects with
which we are dealing prevents us from making any use of our
sense of touch, and we are iu consequence unable to correct the

THE PHYSIOLOGY OF THE SPECIAL SENSES. 145

impressions of one sense by those of another. Hence, if we are
to do good work, we must be extremely careful to distinguish
between what we see and what we think we see. And it is of the
greatest value, when looking at an object under the microscope, to
write down a description of it without using any technical words
whatever, merely describing the objects as dark and light patches,
or areas, giving their size with the micrometer, and describing the
shape of their outline, etc., together with any other physical
details; and, afterwards, to write down what we infer from these
details as to their possible structure and nature. For it is surpris-
ing how often we are led unconsciously to see what we want to see,
and how grossly we can voluntarily deceive our senses,

I will endeavour to prove my statement in the case of all of
you here to-night by a very simple experiment. If I take this
tumbler standing on the table, you see it is upright; if I now tilt
it slightly, the rim at the top is in the reverse position to you.
Now, if you will close one eye or half-shut both, you can see the
rim in the tilted position — that is, the proximal edge of the rim is
now the distant edge, although you know perfectly well that it
could not stand in such a position.''' With a little practice you can
do this with the eyes wide open. Seeing, then, how easily we can
deceive ourselves voluntarily, and how much more easily we may
be deceived unconsciously, it behoves us to proceed very cautiously
in using an instrument like the microscope, and to make as certain
as possible that our data are accurate before we proceed to draw
our conclusions.

The association between stimuli and mental pictures is so close
and remains so long, that often a sudden stimulus, similar to one
received many years before, may bring back the whole mental
picture with extreme vividness. This is especially the case with
the sense of smell. The slightest stimulus of the organ of smell,
not even sufficient to be noticeable to us as distinct, may bring
back some long-forgotten scene, whilst we puzzle over what could
have made us think of it. And I may here note by the way that
in man the sense of smell is apparently to a great extent a lost
sense. It is not nearly so highly developed as in the lower

* I am indebted for this experiment to Mr. Waller; a full description can be
found in his Human Physiology^ p. 542, published by Longmans and Co.

146 THE PHYSIOLOGY OF THE SPECIAL SENSES.

animals, because it is not so much required, in our present condi-
tion, for hunting out our prey or scenting danger at a distance.
But the sense is occasionally very highly developed in individuals,
and this, or something allied, may be the case in the persons who
are reputed to be able to state where water will be found on boring,
without any previous knowledge of the locality.

That any persons should be thus endowed by Providence with
such a special power apart from the rest of mankind, for the sole
purpose of making a livelihood, may be sufficient explanation for
the uneducated ; but if the power be there, it seems possible that
it is the epithelium of their organ of smell which is capable of
appreciating some atmospheric condition insufficient to affect most
of us. At least, this is a possible explanation.

The sense of taste, so-called, is very largely the sense of smell,
and not taste at all. Thus, the ordinary aromatic flavouring sub-
stances used in cookery do not affect the tongue and palate, but
the smell organ in the nose. In fact, the only things we really
taste are bitter, sweet, and acid substances. The senses of taste
and smell are. when both put together, very small in the informa-
tion they give us of our surroundings, A smell gives us no idea
of the shape, size, or quality of a substance ; nor is it of any use
except to warn us of dangerous materials in the atmosphere or
food, or to stimulate our desire for food.

Of the other senses, time compels me to leave out very much
that might be said of extreme interest to us all, and I must content
myself, in conclusion, with a few words as to the sense of Pain.
Why do we suffer pain ? What good is it ? What is it ? These
questions must occur very frequently to all who are themselves
sufferers, or have the said opportunities of seeing pain in others.

To take the last question first, pain is a conscious impression
of excessive or harmful peripheral stimulation. It is to a certain
extent possible to localise it, but we get little or no information as
to the cause of the pain. The w^hole sensation begins and ends
in the consciousness of ])ain and the attempt to get rid of it. Pain
varies in many ways, according to the seat of the irritant. Thus,
certain noises, such as the squeak of a slate pencil, produce on
certain persons not only the sense of sound, but also of actual
pain. So also with vision, though the pain differs from that pro-

NOTES B^OR BEGINNERS IN MICROSCOPY. 14-7

duced on ihe body at large, Pain does not require peripheral
terminal cells, like the special senses; for if you knock the skin off
your knuckles, the spot will be painful when touched, at the same
time as it will have lost the delicate sense of touch. Moreover,
painful impressions may arise in the deeply-seated organs of the
body. What is the good of pain ? It warns the Central Nervous
System of something locally wrong and ensures rest for the painful
part, thus giving the first and best chance for repair to take place.
When our first ancestor first injured himself, we can picture his
astonishment at feeling this new sensation, his quickly discovering
that movement increased his pain, and his consequent resting of
the wounded part till it healed. Pain, then, has some value in
this colony we call man ; it is the message from some outlying
units that they are out of working order and must be given rest,
whatever their rest may mean.

1Rote6 for BcQinnerB in flDicroscop^.

By R. N. Reynolds, M.D.

Micro-Organisms of the Teeth.

THOUSANDS, if not tens of thousands, of bacteria of various
kinds and motions may be plainly seen swimming about in
each field of the microscope by employing the following
method : —

Place on any good microscope a Wenham paraboloid and a
good half-inch objective.

The specimen may then be taken from the natural teeth of
any human mouth by placing the points of curved forceps or
other instrument near the gum between two of the lower back
teeth, then giving one scrape upward. A pin-head size of tartar
will be found on the forceps, and should be broken up in a drop
of water on a glass slip. On this lay a cover-glass and place on
the stage of the microscope. When fully illuminated by the
paraboloid, the pieces of tartar will appear as white as snow, but
we shall see no bacteria ; next turn the mirror until the light is
beginning to lessen, and we shall soon reach a point at which we

148 NOTES FOR BEGINNERS IN MICROSCOPY.

shall be able to plainly see that the dark water between the pieces
of tartar is teaming with thousands of bright points moving about.
On closely inspecting, we shall see the long Leptotkrix, many
kinds of shorter bacteria, and round micrococci, all apparently
having a grand outing in a drop of water.

The half-inch objective is too low a power for the study of
bacteria ; but in the manner stated will show ten thousand at a
glance, while a high power will show only a very few at a time.

In using the half-inch and paraboloid on the bacteria, we must
not forget that after we have the bacteria in plain view, a very
slight movement of the mirror will leave us unable to see them.
Hence, the mirror should be moved very slowly while we watch
closely in the dark water between the bits of tartar.

Vinegar Eels.— These litde creatures are very popular with
beginners in microscopy, and by the following method they can
easily obtain a grand view of them, and one which will remain in
focus for months if desired.

Take a one-dram clear glass vial ; fill it about one quarter full
of cider or other vinegar well supplied with eels. Into this drop
a silk thread, so that one end rests on the bottom, the other end
hanging out of the vial. The thread will cling to the side of the
vial from the top to the vinegar, and by capillary attraction keep a
film of vinegar along its side.

To hold the vial on the microscope stage, take a bit of cigar-
box or other thin wood, about one and a-half inches wide by two
and a-half inches long ; across its centre draw two lines three-
eighths of an inch apart. The space between these lines is to be
hollowed out to fit the side of the vial ; the hollow space is to be
blacked with ink.

Next to the hollow cut a hole, about three-eighths of an inch
wide and five-eighths of an inch long, through the block, the
length of the hole to run crosswise of the block. This hole is to
allow the light from the sub-stage illuminator to pass through.
Then cut a quarter-inch square out of each corner of the block ;
now pass a small rubber band under one end of the block, up
through the cut corners, thence across the vial groove, and under
the opposite end.

NOTES FOR BEGINNERS IN MICROSCOPY.

149

The vial may now be slipped under the rubber band into the
groove ; the rubber will then hold the vial in place. Turn the
vial until the thread in it is on the upper side ; then place the
block on the stage of the microscope ; use about | or i inch
objective; naturally, sub-stage illumination is used. The light
may now be thrown on the thread ; adjust for the thread above
the vinegar ; the eels will then be seen going up and down the
thread, but cannot get out of focus, although they may, of course,
move out of the field. With vinegar well supplied with eels, large
numbers of the eels will be in the field at any time of day or
night for months. The cork of the vial must have a notch or slot
cut in it to admit air to the eels.

Fig. 7.

With the mirror swung well to one side and the ink-black
background, the eels will appear nearly white. They will often
gather in bunches on the thread. This arrangement is very satis-
factory, and is very much better than that of placing a drop of
vinegar on a slide. If this is done, a i-inch or 2/3rd inch objec-
tive is best for their purpose.

A little more trouble will considerably improve the fixture, but
makes it more delicate. The improvement is in cementing with
Canada balsam a half-inch or five-eighth inch cover-glass on to the
vial, to give a flat instead of a round surface to look through.

The cover-glass may be protected and the vial held by a thin
metal holder instead of the wooden one, the metal holder passing
over the vial and cover-glass.

[ 150 ]

Xacqucring flDicroecope ZTubee anb Stance."

By Dr. Frank L James, St. Louis. Mo.

THE art of lacquering, like every other, requires some expe-
rience to get good results. The writer has been in the
habit of closing the tubes with close-fitting corks and plac-
ing them in hot water. This ensures an even temperature through-
out, and the corks afford a good handle to hold them with during
the application of the lacquer. Another precaution, too often
neglected, is the removal of all old lacquer before the application
of fresh. The following is the method employed by the writer : —

The tubes are corked to prevent the ingress of cleaning mate-
rial, water, etc., that might atfect the dead-black inner finish (and
thus affect the definition of the visual apparatus), and are then
washed with the soap-mixture described belowf to remove the
lacquer. They are then carefully polished with putz pomade, the
operation being finished with a piece of chamois, sprinkled with
the finest levigated chalk. A second washing with the soap
mixture and warm water removes the last traces of grease and
polishing material, and the tubes are placed in hot water. The
lacquer consists of red shellac, dissolved in alcohol of 95^, about
I ounce of lac to 10 or 12 ounces of spirit. This gives a very
pale lacquer, which may be darkened by the use of dragon's blood
or given a yellow hue by gamboge, sandarac, anatto, etc. Appen-
ded hereto will be found some formulae that we have tested and
found reliable.

The lacquer is poured into a saucer, or small open dish, and

* From the National Druggist.

t This mixture is usually made out of the refuse alcohol, and benzol used in
washing, clearing, etc. , in mounting (small portions that cannot be returned to
the container without redistillation). The bottle is kept handy, and fresh soap
is added from time to time, no particular regard being paid as to proportions.
A good formula would be as follows : — ■

Shaved Castile Soap ... ... ... i part.

Alcohol, 94*^ to 95* ... ... ... 3 ,,

Benzol ... ... ... ... 3—4 „

Liquor Potassse ... ... ... ... i ,,

Mix and shake from time to time.

LACQUERING MICROSCOPE TUBES AND STANDS. 151

the brush should be very soft, and for large articles flat. For
smaller articles, a round camel hair or sable pencil will answer.
The tube is removed from the water, wiped, and held for a moment
to ensure dryness, and the lacquer then applied as rapidly and
smoothly as possible. The brush should be drained on the side
of the dish, in order to avoid getting too much of the liquid on
the object at once. If a second coat is deemed necessary, let the
first become quite dry before applying it. If the tube is not warm
enough, return it to the liot water for a few moments and dry
carefully. The water should not be too hot, or there is danger of
blistering the lacquer. From 150^ to 160° F. is a good tempera-
ture. In applying the lacquer, care should be taken not to rub
the object with the brush. Apply it with light strokes, all in the
same direction.
I. — Pale Gold.

Shellac, quite clean ... ... i part.

Ground Turmeric ... ... i ,,

Alcohol ... ... ..." 4 ,,

Mix and set aside in a warm place and let stand, with frequent
agitation, until the lac is dissolved. Decant the clear liquid and
preserve for use.

2. — Yellow Gold.

Shellac ... ... ... 25 parts.

Turmeric ... ... ... 4 ,,

Dragon's Blood ... ... i „

Alcohol, 95^ ... ... 70 „

Digest for eight days, with frequent agitation ; decant and filter.
3. — Deep Red Gold.

Spanish Anatto ... ... 2 parts.

Turmeric, powdered ... ... 30 ,,

Red, Saunders' ... ... 3 „

Alcohol, 95° ... ... 480 ,,

Infuse in the cold for twenty-four to thirty-six hours, shaking
occasionally. Let stand until settled ; then add

Shellac ... ... ... 60 parts.

Sandarac ... ... ... 15 „

Mastic ... ... ... 15 „

Canada Balsam .,. ... 15 ,,

152 BRITISH HYDRACHNIDiE.

When dissolved, add lo parts oil of turpentine. Upon highly

polished brass this gives a deep red gold colour that is lasting and

very handsome.

For a lacquer to use on cold metal we give the following, but

do not recommend it, or, in fact, any cold lacquer : —

Shellac ... ... ... 1 6 parts.

Dragon's Blood ... ••• i »

Anatto ... ... ••. 8 „

Alcohol ... ... -.. 256 ,,

Digest together until the shellac is dissolved ; strain, etc., as No. i.

Brit(0b Ibijbracbniba^^

By C. D. Soar. PI. X.

WHEN we consider the great number of natural history
societies and microscopical clubs that are in existence in
Great Britain, it makes one wonder why that interesting
family of the Acarina — viz., Hydrachnidce — have been so long
neglected. Perhaps the want of good text-books on the subject
is the reason. There is no work on the Hydrachna in English.
Andrew Murray, in his " Economic Entomology — Aptera,^' men-
tions a few species, but some of them are wrongly named and the
drawings very bad. Dr. F. C. George, in the pages of Science Gossips
gave a few papers and a few good illustrations, but did not get
further than a few species of one genus. The last edition of
Carpenter dismisses the subject in about six lines. There are a
few isolated papers in Microscopical Journals, but I do not think
any are much more than a mere reference to the subject. On the
Continent a great deal has been written from Miiller to Neumann.
I propose, with the editor's permission, to give a paper from time
to time on the British Hydrachnidae, each paper to illustrate a
genus, with one species merely as an example ; the letterpress to
be as brief as the subject will allow.

This, I hope, will lay a foundation for anyone about to take up
the study of these interesting mites. The illustrations will all be
from my own drawings taken from the life and all measurements
in English.

BRITISH HYDRACHNIDiE. 153

Genus, Axona (Kramer)."

Body chitinous, with a granulated surface and a depressed line
round margin of body. Legs short, not very hairy, but adapted
for swimming ; all tarsi have claws. Epimera fused together into
one group. Palpi, long. Fourth joint, spoon-shaped ; second
joint has a small, peg-like process. Eyes widely separated and
near margin of body. On each side of the operculum is a special
plate, containing three copulative pores. Mandibles in two dis-
tinct portions.

To illustrate above genus, I give species, A. versicolor.

Axona versicolor fMiiller, Kramer).
1776. — Hydrachna versicolor, Miiller, Zool. Dan. Prodr.^ p. 191,

N. 2285.
1781. — Hydrachna versicolor, Ibid., Hyrachnc^, etc., p. 77, Tab.

VI., Fig. 6.
1793. — Tromhidium versicolor, J. C. Fabricius, E7it. Syst., Tom. II.,

p. 400, N. 9.
1805. — Atax versicolor, Ibid., Syst. Atitliatorum, p. 367.
1835 — 41. — Arrenurus versicolor, C. L. Koch, Deutschlands Crust.,

etc., N. 13, Figs. 16, 17.
1854. — Arrenurus versicolor, Bruzelius, Berkr. 0. Hydrachn. som.

forck., I. Skane, p. 33.
1875. — Axona viridis, Kramer, loc. cit., p. 311, Tab. IX., Fig. 19.
1879. — Axona versicolor, Neuman, Sveriges Hydrachnider, p 74,

Tab. XL, Fig. 2.

This very beautiful mite has been shifted about from one genus
to another several times ; but I hope it has at last found a resting
place where placed by P. Kramer in genus Axona. The mites,
both male and female, from which the drawings are taken were
found in the river at Woking on July 14, 1894. The female is
about i/5oth of an inch long; the male a little longer. In colour
it predominates in a blue-green, with patches of red and white.
The epimera is nearly all (but the actual centre) a very vivid green.
The centre is a beautiful pink. Koch gives a figure of both male
and female, but different in colour. In the specimens from which
* P. Kramer, Beitr. zur Naturgeschich. der Hydrachniden, p. 310, "Axona,"

1875.
International Journal of Microscopy and Natural Science.

Third Series. Vol. V.

M

154 BRITISH HYDRACHNIDiE.

I drew my figures, the colour is identical in both. Miiller gives a
figure, but not coloured. Neuman gives a beautiful drawing in
colour, but the colour does not quite correspond with those found
by me ; neither does the shape, but this may be only a local varia-
tion of the same species.

The body of the female is nearly round, flattened in the front
part. The body of the male is pear-shaped. On the fourth joint
of the fourth leg of the male will be seen a peculiar process, which
is also found on males in other genera. The legs of the male
are also stronger and better developed than they are in the female.

EXPLANATION OF PLATE X.

Fig. 1. — Dorsal view of female.
2. — Ventral view of ditto.
3. — Side view of palpi of female.
4. — Fourth leg of female.
5.— Dorsal view of male.
6. — Ventral view of male.

J)

5 J
5)
J)

Pain in the Eyes. — Pain in the eyes after reading or minute
work of any kind is often due to spasm of the muscle of accom-
modation. Engravers and workers with the microscope frequently
suffer severely. The pain comes on after prolonged application,
and is usually of a dull aching character. Not infrequently it is
attended with a little feeling of sickness and considerable depres-
sion of spirits. The best thing is to lie down in a dimly-lighted
room when the pain comes on, and place over the eyes and eye-
brows a pad of lint dipped in cold water. A small piece of
mustard-leaf to the temples or behind the ears will ease the pain.
We have found relief from bathing the eyes with a very weak
solution of atropine, prepared by putting a drop or two of the
solution of atropine (liquor atropice) in a tumbler full of water.
It is to be used occasionally as a lotion, but must not be taken
internally. Arnica often does good ; it should be taken according
to Pr. 42, and also applied locally in the form of the arnica lotion
(Pr. 94). When the pain is the result of prolonged work by
gaslight, nux vomica (Pr. 44) may be used.

— From '* The Family Physician " for March.

Journal of Microscopy N. S.Vol,5. Pl.lO

^^SSil

-"•^■'^^

ryrrr^i

z60

C^as.D.Soar, ad nat.cfe/.

AocorL(X' Versi.C(:?lo'r

/\P/)l//ip6 Sc.

[ l'^5 ]

Xcavc0 from m^ 1Rote:^Bool^.

By Mrs. Alice Bodington, British Columbia.

SOME INSTANCES OF THE INFLUENCE OF THE
ENVIRONMENT IN PRODUCING RACE PECULIARITIES.

I. — Cats and Rats in Cold Storage Warehouses.
2. — The Paradise Fish of Japan.
3. — The Indian Ghost Flower. (Plate XI.)

MR. Herbert Spencer, in his chapter on Heredity, says
that, "excluding those inductions that have been so fully
verified as to rank with exact science, there are no induc-
tions so trustworthy as those which have undergone the mercantile
test. When we have thousands of men whose profit or loss
depends on the truth of the inferences they draw from simple and
perpetually repeated observations ; and, when we find that the
inference arrived at and handed down from generation to genera-
tion of these deeply interested observers has become an unshake-
able conviction, we may accept it without hesitation. In breeders
of animals we have such a class led by such experiences, and
entertaining such a conviction — the conviction that minor peculiari-
ties of organisation are inherited as well as major peculiarities." '■'

With the remembrance of this chapter in my mind, I was
particularly interested in an account of the development of a
peculiar breed of cats in the "cold storage" warehouses of
Pittsburg, Pennsylvaniat ; these warehouses being maintained
constantly at a temperature below freezing point. At first, no rats
could maintain existence under such Arctic conditions, a most
convenient state of things where toothsome eatables are kept.
But in a few months nature proved herself equal to the occasion,
and a breed of rats appeared which could withstand the low tem-
perature. Not only were their bodies clothed, as might be
expected, with remarkably long and thick fur, but even their tails
were covered with a thick growth of hair. Dr. Manley Miles, in
a paper read at the Brooklyn Meeting of the A.A.A.S., August,

* Principles of Biology^ Vol. I., p. 241.
t Pittsburg Despatch, quoted in Public Opinion.

156 LEAVES FROM MY NOTE-BOOK.

1894,* says that the conditions of artificial selection differ so
much from those of natural selection that it is difficult to carry on
experiments in artificial selection, which are biologically valuable ;
but in the case of the rats and cats in the " cold storage " ware-
houses of Pittsburg, natural and artificial selection have existed side
by side with results equally interesting, as showing the action of the
environment in modifying organisms.

The thickly-furred rats above mentioned made themselves at
home in all the warehouses, and efforts were naturally made to
introduce cats, but at first in vain. The first cats turned into the
icy cold room pined and died. But advantage was taken, as is
usual in artificial selection, of a slight natural difference, and one
cat, which possessed unusually thick fur, proved not only able to
withstand the cold, but actually throve and grew fat. By careful
nursing a brood of seven kittens was raised in the rooms of the
Pennsylvania Storage Company, and developed into sturdy, thick-
furred cats, suited to an Icelandic clime. These original kittens
were distributed amongst the other " cold storage " warehouses in
Pittsburgh, and have been the progenitors of a peculiar breed of
cats adapted to the conditions in which they must find their prey.
Their tails are much shortened, and their hair is as thick and as
full of under fur as that of the wild cats of the Canadian woods.
But one of the most striking features in these cats, from a biolog-
ical point of view, is the development of the sensitive hairs on
the face, popularly called " feelers." In the ordinary cat these
sensitive hairs are about three inches long, but in the cold ware-
house cats they grow to a length of five and six inches. This is
a modification which has arisen de novo ; probably from that
condition of their environment, which obliges the animals to find
their prey in semi-darkness. There was, perhaps, a " predisposi-
tion on the part of the germ " in the mother cat, as Professor
Weismann would say, to grow thick fur ; but the germ does not
seem to have indicated any change in the feelers of the ancestral
pussy.

The storage people state that if one of these furry cats is taken
into the open air, especially in summer time, it will die from con-
vulsions in a few hours.

* <<

Limits of Biological Experiment," American Naturalist, Oct., '94, p. 845.

LEAVES FROM MY NOTE-BOOK. 157

Paradise Fish. — I have read an account in an American
Magazine of the so-called " Paradise Fish " of Japan, but I can
find no account of it in any work I possess. It seems from its
habits to be a species of Stickleback {Gasterosteiis). At the
mating season, the male, which is ordinarily of a dull silver hue,
exhibits brilliant stripes of red, blue, and green, its ventral fins
showing streaks of brightest orange ; hence, doubtless, the Paradise
Fish has acquired its name. It breeds freely in confinement, and
requires no change of water in the globe or aquarium except
enough to make up for evaporation. It is very tame and " sur-
prisingly intelligent," and its habits at the breeding season render
it a pecuharly amusing pet.

When the female is about to lay her eggs, the male fish makes
a nest at the bottom of the water composed entirely of air-bubbles.
For this purpose he swallows air and ejects it in the shape of
bubbles, which are held and made permanent by glutinous capsules
from a secretion in the fish's mouth. When the female lays her
eggs she would devour them immediately, but the male will not
permit her to do so. He takes them in his mouth, and going
beneath the nest ejects them, when they rise and find a resting-
place amongst the bubbles. Or, sometimes, he will conduct his
mate under the nest, so that the eggs as she lays them will ascend
and lodge in the nest. The laying being concluded, and all the
eggs disposed of in this manner, he keeps guard at the nest, not
allowing the female to approach it, and even attacking her fiercely
if she makes the attempt. At the same time, he occupies himself
continuously in making fresh bubbles of air in the place of those
that burst, and at intervals he spouts streams of air all round the
nest, apparently for the purpose of keeping it thoroughly aerated.
After about five days, during which this performance is kept up,
the young are hatched out. They cannot swim, but cling like little
tadpoles to the bubbles. If one falls to the bottom, as happens
every now and then, the father fish darts after it, takes it in his
mouth, and conveys it beneath the nest, where he disgorges it
among the bubbles again. Thus the Paradise Fish continues to
take care of its offspring for several weeks.

Everyone knows of the Water Spider, which makes a little
diving-bell of bubbles of air, in which she lives quite dry and spins

158 LEAVES FROM MY NOTE-BOOK.

her silken cocoon with its hundred eggs ; only coming to the
surface to secure water-flies and other small insects and to provide
herself with fresh bubbles of air, which adhere to the hairs on her
body and keep her perfectly dry. This is a sufficiently strange
instance of the adaptation of an air-breathing animal to life at the
bottom of the water ; but it would be impossible to say for how
many thousands of years the Water-Spider has made her diving-
bell ; whereas the Paradise Fish must have learned the art of
bringing up its young in insufficiently aerated water during that
comparatively brief time since human civilisation has begun, and
men have had leisure to enjoy the keeping of fish as pets and the
art to construct receptacles in which to keep them.

It would be particularly interesting to know in what manner
the fish supplies itself with fresh air on ordinary occasions, since,
as it never requires change of water, it must possess some means
of oxygenating the water in which it lives.

Indian Ghost-Flower {Monotropa unifolia. PI. XI).— This
poetical name has been given to an aberrant member of the genus
EricacecE, which, from its fungus-like manner of obtaining its
nourishment, has taken on the superficial appearance of a fungus.
Walking in a trail through our woods one afternoon last autumn,
I saw, as I imagined, a group of very pretty graceful fungi amidst
the bracken. On picking a bunch of these apparent fungi, I
found the wax-like, colourless stem supporting an equally w^ax-like,
colourless flower, the whole being in shape very like a minute
tobacco-pipe. Further examination showed a flower which placed
the plant amongst the most highly developed of the dicotyledons.
No amount of search showed any trace of a root. The pointed,
colourless end of the Ghost-Flower simply penetrated deeply into
a deposit of completely decayed wood. A few small, colourless
scales represented all it possessed of leaves, the whole plant being
absolutely destitute of chlorophyll, and having the appearance of
being made of white wax, resembling in this respect a true fungus
which grows in the same woods. No mere description, however,
can give a correct idea of the peculiar stifl'ness of these groups of
little pipes. In decaying, they also resemble fungi in turning of a
black colour. I find no mention of this peculiar plant in Balfour's
Botany nor the E?icyclopcedia Britannica, but it is known on the

Journal of Mieroscopy N. S.Vol, 5.PI11

/)

'J i

'M

r^

ft

Miss I'Voods ao' nai def.

A Pkif/ips Sc

OTcOtropa unif'loray.

LEAVES FROM MY NOTE-BOOK. 159

eastern as well as on the western side of the Rocky Mountains.
It seems a most interesting example both of adaptation and of
heredity, the flower being undegenerate, and like that of any other
heaths, whilst the rest of the plant is changed almost beyond
recognition, owing to its saprophytic habit of life. This year I
have, as yet, been unable to find the plant, or I would give a more
exact description of the flower. A lady who has made a large
collection of British Columbia plants says that she also has been
unable to find any semblance of a root in the Ghost-Flower.

I do not suppose that any of the evidence of adaptation to
the environment given in the foregoing instances wfll have any
effect on those who deny this power of adaptation ; but the facts
themselves must be of interest both for Neo-Lamarckians and for
followers of Professor Weismann.

[After sending the preceding paper, Mrs. Bodington wrote
to the Union Storage Co., of Pittsburg, Pa., and in forwarding
us their reply she very pathetically says : — " It turns out that
there are no rats with furry tails in the business ; no cats with
abnormal whiskers ; no convulsions on being taken into the open
air; no constant cold and darkness, and nothing to demolish
Prof Weismann." The following is the letter referred to.— Ed.]

^'Dear Madam, —

Your favour of the 3rd inst. was handed to the writer a few
days ago. While there is some foundation for the newspaper
article, a copy of which you enclosed, it is somewhat exaggerated.
We are engaged in the storage business, having several warehouses
for general storage, and one large house for cold storage. The
cold storage house is separated into rooms of various sizes, varying
from 10 degrees to 40 degrees above zero. Our experience has
taught us that the best way to destroy mice that are likely to come
in goods sent to us for storage is by the use of cats.

About a year ago, for the first time, we discovered some mice
in one of the rooms in our cold storage house. We removed one
of the cats from our general storage warehouse into the room
referred to in our cold storage-house. While there, she had a
litter of seven kittens. Four of these we transferred into one of
the other warehouses, leaving three in the cold storage house,
where they now are. After the kittens were old enough to take
care of themselves, we put the old cat back into the house we had
taken her from. The change of climate or temperature seemed to

160 LEAVES FROM MY NOTE-BOOK.

affect her almost immediately. She got very weak and languid.
We placed her again in the cold storage-house, when she imme-
diately revived, and seemed to be filled with new life and energy.

While the feelers of the cats in the cold storage-rooms are of
the usual length, the fur is very thick, and the cats are larger,
stronger, and healthier than the cats in any of the other ware-
houses. They have been transferred from room to room, the
temperature, as above stated, varying from 15 to 40 degrees. The
building is lighted by electric lamps, but most of the time there is
no light. Until last Saturday the cats had never seen natural
light. Saturday afternoon we had two of them carried to the
shipping platform on the first floor. When the men got on the
elevator with them, the cats looked surprised and startled, and
struggled to get away, although always very playful and happy in
the rooms above. They were evidently so badly frightened that I
had them immediately taken back to the rooms. The original
cats are common, every day pussies.

We paid no particular attention to their diet, giving them milk
once a day and meat once a week. Sometimes the workmen will
give them some scraps from their dinner-pails.

Will be glad to give you any further information you may want
regarding the matter, and follow any suggestions you may care
to make.

One of our warehouses for general storage is a six-storied
building with cellar, the average height of the floors being 12 ft.
There is no communication from one floor to the other except by
elevators. On each floor in the house we have one or two cats.
In cold weather, after the warehouse is closed and absolutely dark,
the cats jump from the floor above to the floors below, in that way
going from one floor to the other until they reach the cellar, for
the purpose of spending the night close to the steam elevator
engine. Each morning the cats are carried from the cellar floor
to the different floors above. Yours very truly,

S. Bailey, Jnr.,

Sec. and Treas."

1,^

Experiments continued through many years, by Dr. S.
lideal, show that the chemical activity of sunlight during winter
on the high Alps is much greater than at lower levels, and enor-
mously greater than in large towns at the same season. This
increased activity may contribute in an important manner to the
beneficial eftects of health of residence in such regions.

[ 161 ]

Bacteiia of tbc Sputa anb Cr?ptooanuc
flora of tbe fIDoutb.

By Filandro Vicentini, M.D., Chieti, Italy.

SECOND MEMOIR.

Translated by Professor E. Saieghi.

IRecent JBacteriological IResearcbes q\\ tbe Sputa;
tbe /IDorpboloG^ an^ JBiolOG^ oX tbe /IDicrobes
ol tbe /Iboutb,

Further Remarks on the Bacteria and Bacilli found

IN the Sputa.

§ in.

OPINIONS HITHERTO HELD RESPECTING THE MICRO-
ORGANISMS OF THE MOUTH, according: to Miller.

History and General Facts.

WHEN I for the first time began to examine the fructification
of Lepfot/irix, of which no mention had hitherto been
made in the ordinary text-books of microscopy, I, of course,
consulted several of the special publications quoted in the Biblio-
graphical Appendix, in order to ascertain whether others had des-
cribed these fructifications before; but my search was fruitless.
It is true that Robin believed in their existence, as appears
from the quotation at the beginning of this Memoir; but the
granules mentioned by him are simply the reserve gemmules of
this microphite. However, I should not have been induced to
treat on this subject so early, had I not unexpectedly met with a
very conspicuous specimen of such fructification in some pulmo-
nitic sputum (see Fig. t6). I then wished to acquaint myself
with the last work of Miller, already quoted, and on perusing it,
I found that he had not even touched on that point ; but, on the

162 BACTERIA IN THE SPUTA

contrary, his views were, in a sense, diametrically opposed to
my own.

Of the specimen found in the pulmonitic sputum I shall
speak in Section 4. According to Miller, the opinions hitherto
acquired on the microbes of the mouth would be as follows : —

In the 3rd chapter of his volume, " The Micro-Organisms of
the Buccal Cavity : Local and General Complaints produced by
them " (the most complete and most recent work on the subject),
the illustrious Berlin Professor goes on to relate the ancient and
recent scientific opinions on the microbes of the mouth, beginning
with their discoverer, Leeuwenhoek, who, in 1683, discovered
first on his own teeth, always kept clean, and afterwards on those
of an old man, '■''magna cum admiratio7ie^^ animalcules, drawn by
him (Fig. 10 of Miller), some of which resemble the Comma
bacilli -.—^^Multa exigua admodimi animalcida jiicundissimo modo se
move?iHa."

Lebeaume compared the tartar on the teeth to coral formations.
Mandl held that the tartar proceeded from the chalky remains of
the vibriones described by him, which he thought would be killed
by heat, by hydrochloric acid, and alcohol. Biihlmann was the first
to observe and describe the fi.laments of Leptothrix, without,
however, giving any opinion as regards their vegetable or animal
nature.

Henle was the first to declare that these microbes were of a
vegetable nature.

Erdl treated the decayed teeth with hydrochloric acid, and from
the crown he obtained a kind of delicate, enveloping membrane,
composed of parasites.

Ficinus dealt diffusely with microbes of the buccal cavity,
which he held to be of an animal nature, and gave them the
generic name of dental animalcules. He described the filaments
of Leeuwenhoek and of Biihlmann, the granules, the epithelia, the
corpuscles of mucus, forming the patina dentaria, as well as
certain infusoria that accidentally dwelt there. He not only held
the bacteria and bacilli to be real animalcules in brisk motion, but
he imagined also that they possessed a mouth. He grouped them
with infusoria without cilia, probably shelled, after the types of the
genera Paramceciimi and Colpoda.

AND CONTENTS OF THE MOUTH. 163

In 1847 Robin thought that the principal micro-organism of
the mouth was an alga which he called Leptothrix biiccalis.

Klencke, continuing the researches of Biihlmann and Ficinus,
drew the dental animalcules, the filaments of Biihlmann (repro-
duced in Fig. II of M.) ; and, following the opinions of Ficinus,
he even drew the mouths on their ventral side, as can be seen in
the quoted figure.

Meanwhile, the ideas of Robin were accepted, and Leptothrix
was generally held to be an alga or fungus siii ge?ieris, excepting
by Frey, who, together with Hallier, thought it to be a form of
Penicillium glaucum^ and by Tilbury-Fox, who restricted it indis-
criminately to a form of Oidium.'''

After these historical hints. Miller goes on to describe his
methods of investigations, from which it appears that the author
and the preceding investigators have not acted with that neces-
sary care and discernment, which has been demonstrated, in
collecting and preparing the contents of the mouth ; nor have they
instituted comparisons with the sputa. They directed their best
attention to the culture of the microbes of the mouth and to the
study of the patina dentaria. They did not avail themselves of
the immersion methods except in the special examination of
certain fragments or isolated microbes and of their cultures. It is
no wonder, therefore, that they should not have met with the fruc-
tifications and the productions of Leptothrix by points.

Miller speaks of cultures on agar or on calf's blood serum, and
from thousands of specimens he gives the preference to agar pep-
tonised with broth, with an additional 0*5 — i per 100 of sugar.

The cultures were made from saliva, the tartar of decayed
teeth, or scrapings from the surface of the tongue or from dental
ulcerations and altered pulps of teeth. The cultures from saliva
in the gelatine were negative. Often the bacteria reared in agar
did not succeed in gelatine, owing to the low temperature main-
tained.

For a general study, he considers an amplification of 20 to
300 diameters sufficient, but for the special morphology he used
a homogeneous immersion lens. He speaks of fungi derived from

* Frey, Bibliography. Tilbury-Fox, by Beale, Work, p. 491.

164 BACTERIA IN THE SPUTA

external sources, as the liacilli of tare, potatoes, lactic acid, green
pus ; and also of the Micrococcus tetragem/s, of Mycoderma aceti, of
Staphylococcus pyrogenes^ aureus^ and albus, to the effect of excluding
them from the cultivations. But he touches again upon some of
these forms in Chapter IX., as we shall see later on.

Miller classifies, afterwards, the microbes really constant, or
primary, of the buccal cavity, into six different species. Of these
we give a list, putting our denominations to each species of Miller.

Synopsis.

Miller : Vicentini :

I — Leptothrix buccalis ( L. Leptothrix buccalis..
hinomitiata).

2 — Bacillus buccalis 7fiaximus. Fragments of stumps.

3 — Leptothrix buccalis inaxifna. Stumps.

4—Jodococcus vaginatus. Special sheaths of bacteria pro-

ceeding from some reserve
gemmules.

5 — Spirillum sputigeiium. Pointed or virgulated Bacilli

(copulatory organs ?)

6 — Spirochcete dentium. Spirillum (fragments of very slen-

der filaments).

The above species or types are found in every mouth. The
Spirillum spiitigenum is sometimes found, in almost a pure culture,
in the carious cavities ; and the Spirochcete dentium near the gums.
The cultures from substances uiixed with saliva, acids, alkalies,
product of caries, dental mucus gathered out of the ebullition
of decayed teeth, do not succeed ; some simple cultures, however,
give productions of 15 or 20 articulations of certain species, but
these cannot be reproduced a second time.

I will now sum up the characteristics which Miller attributes to
these six primary species, beginning with Leptothrix in7wmi7iata.

Leptothrix buccalis {Leptothrix innomi?iata).

The name of Leptothrix buccalis is attributed to Robin, who
applied it in general to all buccal microbes. Hallier, Zopf, and
all others who wrote on this subject conformed to his opinion,
maintaining that the motile bacteria are spores of Leptothrix in

AND CONTENTS OF THE MOUTH. 165

activity, and cocci and bacteria not motile are wandering spores
in a quiescent state.

Leber and Rottenstein found the fine violet staining with iodine
and the acids to be a characteristic of buccal microbes (included
by them in a single species of Leptothrix). Miller, however,
considers such forms to be different species, although they show
the same behaviour towards staining re-agents, for the reason that
the filaments oi Leptothrix 2ire not articulated (as stated by Robin).
On the contrary, the bacilli or filaments under iodine re-agents are
articulated. Now, can this distinctive character be sufficient to
classify a species ? I shall show later that, besides articulations,
bacilli may be found, or knotty little rods in continuity with small
chains, and the latter with fertile filaments (not articulated), as in
Figs. 9 and lo. This demonstrates the fact that such filaments or
bacilli, either articulated or not, or simply in beaded forms or
chains, do not constitute a difference of species. Moreover, the
filaments more woody and articulated, found in the lower layer of
the patina, or, owing to the friction, are left exposed, so that the
remaining stems become thick and hard, and their internal
gemmules give rise to enclosed bacteria. Vignal was not of a
different opinion in holding Leptothrix to be a fungus of the mouth,
which he had reared, although it showed transverse segmenta-
tions easily discernible in aniline. Likewise, Miller, in his article
on Leptothrix gigantea, as we shall see later, entertained the same
opinion.

Quite recently, the dumb-bell bacteria and other fungi of the
mouth were identified with Bacterium termo by Stockwell, Clark,
and others. In the preceding Memoir we held this identity as
plausible ; but Miller positively rejects it because the title of Bac-
teriufn termo would embrace a mass of very different forms and
species. He likewise rejects the title of Leptothrix buccalis (given
by Robin) and of dental filaments (by Biihlmann), names which
Miller would have banished from microphitology. However, he
would give the name of Leptothrix innomi?iata to those little-known
filaments which appear to constitute a group or a species differing
from other fungi. It is clear that the author alludes to our fertile
filaments, making of them a separate species.

The Leptothrix innominata of Miller (the real Leptothrix akin

166 BACTERIA IN THE SPUTA

to fructifications to our knowledge) is to be found in the patina
dentaria {mate7ia alba of Leeuwenhoek) constantly, but in different
quantities in every mouth. It is, of course, very scarce in well-
cleaned teeth, because, lying on the top of the tufts, it is the
first to be removed by friction. The patiita dentaria exhibits large
and small heaps of round granules, and, on the edges, slender
filaments variously bent. The granules were considered as the
matrix of the fungus, having been taken for spores of Leptothrix.
The author thinks them to be either micrococci foreign to Lepto-
thrix^ or simply linking points of its filaments.

The filaments are of varied length, from 0*5 to o"8 micro-
millemetres, sometimes twisted, usually still, and without articula-
tions (but this is not always exact). They generally have irregular
contours and appear to be badly nourished or are dead, but we
shall see that they contain gemmules and bear spores (ears ?).
In their surroundings there are also numerous shorter filaments
or small rods, which the author thinks might be simply fragments
of longer filaments, or cellules of the fungus not having yet
reached their full development.

By using the solution of iodine, slightly acidulated with lactic
acid, under a power of 350 diameters, epithelia and clusters of
micrococci can be detected intermixed with them (Fig. 12 of
Miller), and even various forms of little rods and filaments of
Leptothrix lightly tinged with yellow. Other larger bacilli become
tinged with deep violet, and these are called by the author Jodo-
coccus vaginatus and Bacillus buccalis maxinius.

The same author again speaks of the Leptothj-ix innomifiata on
page 203. He declares positively that it cannot be cultivated in
every medium. This is true, if he intends to speak of the ordinary
culture media, but not equally so with regard to sputa, in which
are to be found not only natural cultures, but even the most vigor-
ous fructifications of this parasite, as we shall see later on.

Other Primary Micro-Organisms of the Mouth.

Bacillus buccalis maximus.— This consists of isolated bacilli or
filaments, more frequently of bundles. The filaments of the
length of 30 — 50 micro-millemetres (Fig. 13 of Miller, stained
with the acidulated solution of iodine) are distinctly articulated.

AND CONTENTS OF THE MOUTH. 167

The isolated bacilli or articulations are from 2 to lo micro-mille-
metres ; their thickness is from i to i'3 mm. Of the primary
fungi of the mouth this is the greatest ; all its parts cannot be
coloured with iodine (Fig. 14 of Miller to be compared with our
Fig. 2, w, w, n^ ;?, n\ q, r, and with Fig. 5, a, b, c, d). It is not
detected in the dental tubuli, probably because it is too big to
penetrate there.

Miller holds it to be of a different species from Leptothrix
innominata, from its size, and through possessing segmentations or
knots, and not bending in zig-zag ; and also on account of its
very strong behaviour towards iodine re-agents. But these points,
very feeble in themselves, are not even constant. Take, for
example, the specimen drawn in Fig. 9, d^ in which the filament
of Leptothrix (fertile filament not segmented) springs from a por-
tion of the chain which rose on the top of a large, knotty filament.
If these large filaments appear in stumps or in separate networks
it is owing to the growth of superior vegetation and the subse-
quent rubbing off of the latter by friction.

I shall presently show that Leptothrix living in the water is abso-
lutely identical with this Bacillus maximus of Miller.

I have, however, to observe that very distinct segmentations
exist sometimes, even in the most slender filaments. In Fig. 5,^,
I observed an opaque segment, deeply coloured in the middle,
with two clear, pale segments at the ends. This filament^ com-
pared with bacillus d (same figure), hardly gives the thirtieth part
of its thickness. Miller himself, in his previous work of 1883 on
Leptothrix gigantea, describes small rods and cocci within the
sheaths of filaments of the said Leptothrix (Figs. 2, 3, and 4 of
relative plate). In Fig. 5 he even drew a cumulus of small rods,
sprung out of the filaments through bursting. The very slender
filaments drawn in Figs. 2, 3, and 4 are also articulated.

Leptothrix buccalis maxima.— The same author is not certain
whether this is a really separate species or a younger form of the
same Bacillus buccalis maximus. The only difference consists in
its resisting an iodine reaction, and in the greater distance of its
articulations.

168 BACTERIA IN THE SPUTA

Jodococcus vaginatus (Fig. 15 of Miller, reproduced in our
Fig. 7) is found rather plentifully in uncleaned mouths. Miller
found it only in two children. It is formed of from four to ten
cellules or nuclei, seldom more, placed obliquely in chain, and
having the shape of little flat or round shields, or tetrahedrons.
The chain is either bare, as in /, /, of Fig. 2, or sheathed. The
sheath, large, 075 mm. (I have found some even larger) is colour-
less or takes a yellowish colour, with a long iodine saturation. The
nuclei are tinged with dark violet. At times the sheath is broken,
the place of the nucleus is empty, or it has dropped off.

I shall not repeat what 1 demonstrated in Section I. with
regard to these chains — of their envelope tardily discovered, of
the presence on the same of curved diplococci, morphologically
identical with the gonococcus of Neisser. I shall only state that,
as such forms are found, even of greater dimensions, in urine, and
being intermixed with filaments and other forms of Leptothrix,
their relation with this parasite, which is most widely spread,
becomes still more probable. It is, perhaps, the only one which
lodges simultaneously in the mouth and in the external genito-
urinary mucous membrane.

But, even admitting the Jodococcus vaginatus of Miller to be
entirely different from the small sheathed chains described by us
in Fig. 4, their entity as a distinct species still remains doubtful.
The same author, in the quoted work of 1883, described and drew
(annexed plate. Fig. 8) some articulations divided in two and in
four small cocci, arranged, as in the Jodococcus vagi?iatus, by
couples or tetrahedrons. He even found in the pig whole filaments
of Leptothrix^ made up with a series of those cocci, as we shall
see later.

Spirillum sputigenum (Figs. 16 and 17 of Miller and our Fig,
5, h). — It is found in every mouth, and mostly upon unclean
teeth. We should note this circumstance, as it corroborates our
views. Cleaning the teeth destroys, every time, the pseudo-inflo-
rescences or productions by points, from which would rise those
Comma bacilli, together with the spindle-like and snake-like bacilli.
We shall see, in fact, that the simple act of mastication is apt to
destroy those pseudo-inflorescences, so that we must look for them

AND CONTENTS OF THE MOUTH. 169

on empty stomachs. Is it to be wondered, then, if their products,
and chiefly the Spirillum sputigenum, are so scanty in those persons
who regularly clean their teeth ? Miller goes on to say that in
unclean mouths they are numberless.

These microbes are in the shape of small Comma rods, endowed
with very quick, screw-like movements. When linked by twos,
they form themselves into small snakes, like the letter s.

Lewis, as we have already said, identified this microbe with the
bacillus styled Cholerigemis. However, its presence in the mouth
had been detected before, and by a few attributed to fragments of
Spirochcete. Clark held it to be the cause of caries, for it pene-
trates the dental tubuli as shown in Fig. 17 of Miller. This author
excludes every relationship between the Spirillum sputigenutn and
the bacillus Cholerigemis^ judging from the culture which for the
latter is positive whilst for the Virgula of the mouth it is always
negative, However, this is a new confirmation of our views, for,
if the Commas in question are real organs or copulative filaments,
it is quite natural that, whilst they fecundate the articulations or
the spores, they should be incapable of reproduction themselves.*

In addition to the Spirillum sputigenum, Miller classifies two
other types of curved filaments : one short, massive (Fig. 32),
and motile, which liquifies gelatine ; the other slender, still, and
more curved (Fig. 18). In growing old, it gives rise to a small

* After having completed our work, we found in the Lancet of June, 1890,
an important article by Dowdeswell, on the Comma bacillus of cholera. He
touches on the widely-spread hypothesis that those Commas may be only frag-
ments of spirilla, and then he describes three cycles in their evolution : —

A, Commas or fragments of spirilla which may or may not end in sporules ;

B, Active cellules, with cilia and amoeboid forms ; then round quiescent cel-
lules (sporanges) ending in minute sporules ; C, Active filaments ending in
sporules of the first generation. The author, however, has not succeeded in
reproducing, by any method, the normal Commas, vital and reproductive for
themselves. He affirms that cholera bacilli are to be found, normally, in the
large intestine of the guinea pig, and that the subcutaneous inoculation of a large
number of such bacilli really produces choleriform symptoms in that animal ;
but it is not a true cholera infection. Considering the high temperature that
accompanies it, it is a true septicaemia. The fact, then, that the author nas
found forms of Leptothrix in the Comma bacillus cultures, goes still further to
support our views. Dowdeswell, Note on the ' ' Morphology of the Cholera
Comma Bacillus," mVnQ Lancet, 1890, Vol. i., page 1419 — 23.

International Journal of Microscopy and Natural Science.

Third Series. Vol. V, n

170 BACTERIA IN THE SPUTA

chain of cocci. The author has not detected any spores. Although
this microbe grows in the gelatine, it does so in a different manner
from the cholera bacillus.

Spirochsete dentium (Fig. 20 of Miller and our Fig. 6, c) is not
found in the decayed teeth, but on the edge of the gums, together
with the Spirillum sputigeniwi (affection of the gums). It exhibits
spires 8-25 mm. long, of various thicknesses. The more slender
ones hardly become coloured. The author himself doubts whether
the slender spires constitute a separate species, because he con-
siders the largest amongst them to be akin to the Spirillutn sputi-
genum. Their development is probably unknown. '^ We know
little or nothing (he says) about the vital conditions and their
manifestations, such as fermentation, pathogenic action, etc."

I shall observe that, amongst the materials which came under
my examination, 1 have constantly found these spirilla or spiro-
chcBta with the Leptothrix. In the former Memoir on relapsing
fever, I spoke of Spirilla and Spirochaeta, which, together with
filaments, small rods, and other portions of Leptothrix^ are pro-
duced in infusions of potatoes. In a later paper upon a Dip-
lococcus identical with the Gonococcus of Neisser, in a case of
Carcinoma of the bladder, I mentioned the striking Spirochceta
that are found in the sediment of bottles filled with the stale water.
Together with Zopf, I have retained the name Spirochceta for
those spirilla which bend in the middle, and thus mark a
sort of transition between the so-called Spirillum and the
Spirulina. I may add that, in the sediment of the bottles,
the Spirochceta surround the tiny islands or lumps of a stringy
microphite, which, in its natural state, resembles the filaments of
the Leptothrix giga?ttea from the dog, especially the more slender
ones, drawn in Figures 2, 3, 4 in the already mentioned article of
Miller. On the other hand, the intertwined filaments of that sedi-
ment, being coloured with aniline, resemble entirely the lumps of
the Bacillus buccalis ??iaximus of Miller, after Fig. 13 in the last
work of this author. According to Zopf, Leptothrix is a micro-
phite that lives in the water.*

* Zopf, Die SpaUpihe^ Breslau, 1883, page 80. Vicentini, On a diplo-
coccus analogous to the gonococcus of Neisser, found in urine, in a case
of Carcinoma of the" bladder — Vol. XLiii., Degli Atti Delia R. Accade?nia
di Napoli, 1889.

AND CONTENTS OF THE MOUTH. 171

I have already stated that, in the midst of those masses
of filaments of the sediment in the bottles, there are preserves of
Vorticellas.

Now, it is not improbable that the Spirochceta rise there from
the more slender filaments of the Leptothrix gigantea, and in
the mouth from those of Leptothrix buccalis, as I shall show
later ; and that the Leptothrix gigantea and the Bacillus buccalis
inaximiis, or Leptothrix buccalis maxima of Miller, may be the
same thing. I have remarked that, in the sediment from the
bottles, the vorticellas and filaments are never wanting; whilst the
Spiroehceta are found there only in summer, and then in brisk
motion. Hence, we may infer that the temperature may greatly
influence the production of the Spirilla and the Spirochaeta, as
Miller had argued from the cultures, and as their abundance in
the mouth would prove.

I shall refer later to the Spirilla that, in certain cases, I
have seen accompanying the Leptothrix of the prepuce and the
urethra.

Secondary Micro-Organisms.

Leptothrix gigantea (Fig. 21 of Miller). — This form was found
on the teeth of a dog affected with alveolar pyorrhaea. It
was also found on other carnivorous and herbivorous animals.
It exhibits a vigorous development ; has a bushy shape, like the
Crenothrix', the stems of which deflect at the top, with cocci, small
rods and filaments sometimes alternated on the same line. The
stems are polymorphic of varying thickness. Some increase in
size towards the top ; some are partially or wholly spiral ; and
others double and twist as in Spirulina (Fig. 12 of the plate
annexed to the article of 1883).

In this article, published in the Berichte der Deutsche?!
Botanischen Gesellschaft, are to be found more particulars upon
the microphite in question. The oldest filaments are articu-
lated ; some are spiral and mutually twisted at the base (Fig. i,
E, a). The articulations of the more slender filaments cannot
be detected without colourisation. There are sheathed filaments
whose internal articulations sometimes evacuate and form cumuli
of little rods of different sizes (Fig. 5) ; others become compressed

172 BACTERIA IN THE SPUTA

or swollen, or deviate from the axis (Fig. i, A, B, C). By staining
process we find, particularly in the pig, articulations subdivided
into two or four cocci ; or groups of two or four, which at times
occupy the whole length of the filament (Fig. 8). In the tufts
can be seen straight and tortuous filaments. The bending is
graceful and extended. These are styled by the author, Vibrmiic or
SpirochcEtic forms (reproduced in our Fig. 8). In the more slender
filaments we can observe the transition from the vibrionic to the
spirillic form upon a single filament (Figs. lo and ii). In the
spirillic forms of these slender filaments, by means of a proper
colouration, the articulations can be detected.

In 1883, Miller suspected that the same slender spires of the
Patina Dentaria would rise from the fragments of long and slen-
der tortuous filaments (Figs. 13 and 17). In the dental Spirochseta
there is no trace of articulations, but in the marshy Spirochaeta,
through the weak colouring of Zopf, are detected several articula-
tions in every filament (Fig. 20). Hence, then, the author inferred
that relations existed between the Spiroch^ta and other microbes
of the mouth. But now, in his work of 1889, he seems to have
discarded his former theory of unity of forms.

Miller is unable to say whether the Leptothrix, detected by him
and by others in the tame herbivora and in the pig, is identical
with that which lodges in the mouth of man and of the carnivora.
He says that it would be necessary to institute pure cultures.
Anyhow, it is important to admit the existence of Leptothrix^ even
in the herbivora. Whilst before it was held that Leptothrix lodged
exclusively in the mouth of carnivora, Zopf had already admitted
its existence in the herbivora.* It is true that it is less frequent
in the herbivora ; but, if we are not mistaken, it must be taken
into consideration that these, and especially the ruminants, are
continually using their teeth, so that the parasite cannot thrive
there at ease.f

* Cornhill and Babes' quoted work, page 135 ; Zorpf already quoted.
This author thinks it probable that Leptothrix bnccalis originated from the
external world, especially through water and food. We have already mentioned
the Leptothrix found by us in the sediment of a bottle of water ; but how can
we explain the Leptothrix in genito-urinary passages ?

t Miller, Uebereinen Zahn Spaltpilz, Leptothrix ( Berichte der gigantea
Detitschen Botanischen Gesellschaft^ Heft 5, 1883, p. 221).

AND CONTENTS OF THE MOUTH. l73

Fungi of the Mouth which may be stained blue and violet
with Iodine Colours. — Besides the Bacillus buccalis maximus and
the Jodococcus vagi?iatus, Miller points out three others with a
striking iodine reaction, viz. : — {a) Jodococcus magnus (Fig. 22),
which colours violet ; {b) Jodococcus parvus also stains violet ; and
{c) another Jodococcus^ which takes the rose colour with iodine,
and can be cultivated a first time, but it does not reproduce in a
second culture.

Fungi of the Mouth which can be cultivated.— Some of these
are not pathogenic ; some of a doubtful pathogenic efficiency. In
Fig. 23 of the author are depicted several various types of these
bacteria of the mouth ; in ^, c^ g, screw forms ; in b, cocci ; in
df small rods ; in ^, a sheathed chain of cocci ; in /, a long
chain (but these are numberless in the patina of the tongue, so
that we beheve it to be impossible to separate them from Lep-
tothrix) ; in /, chains of small rods ; and in k, thread forms (to
which the same remark applies).

Miller himself considers it a confusion, difficult to clear up
without immense labour, as all the bacteria of the external world
can form a nidus in the mouth. The author depicts 19 out of the
22 species which he separated in 1885, viz., from Fig. 24 to 27,
cocci; 28 to 29, small rods ; and 30 to 31, still longer rods ; in
Fig. 32, a Vibrio viridans that liquefied the gelatine and produced
a green colouring matter ; a spirillum (Fig. 33) ; long threads
(Fig. 35) ; and small chains, partially sheathed (Fig. 34).

We shall omit seven other types obtained from simple cultures.

Miller afterwards points out the investigations of Vignal, which
he finds fit and accurate. Such investigations led to the cultiva-
tion of 17 species of fungi in pure cultures ; some identical with
known fungi; others unknown. The more frequent was Bacterium
tertfio ; then come Bacillus ulna ; then the Bacillus of potatoes ;
three other unknown Bacilli ; the Bacillis subptilis ; then the
Staphylococcus pyogt7ius albus\ then the aureus ; five other unknown
Bacilli ; and, finally, the Leptothrix.

From that view, there would result for Vignal a great prepon-
derance of bacilli; for Miller, on the other hand, of cocci. Miller
attributes this divergence of results from Vignal having used the

174 BACTERIA IN THE SPUTA

gelatine, on which not all of the above mentioned microbes thrive.

Black, through his own researches, has found in the contents
of the mouth, SU'cptococciis continuosiu, Straphilococcus mediiis,
Staphylococcus magnus, Coccus cu?fiulus minor, and Bacillus
gelatogenes.'''

We have not been able indeed to convince ourselves that, from
those experiments of cultures, a basis may be established for the
identification of the species of bacilli or bacteria, owing to their
unlimited polymorphism, according to the various nourishing media
and the different conditions of their surroundings ; so that, wher-
ever the decisive proof of the fructification is wanting, the results
of the cultures for creeping or immersed vegetation cannot be
freely accepted as the same. In doing so we might run the risk
of multiplying the species and the true or supposed pathogenic
properties of bacteria, ad infinitimi.

Different particles or cellules of the same organism may, in
fact, need various nutrient media ; they may liquefy certain sub-
stances, and separate others of a very different nature ; as, for
instance, the bony corpuscle, the hepatic cellule, the blood cor-
puscle, the Ilenal Epithelium, etc. The poison of insects or
snakes is not diffused throughout their organism, but it is secreted
by special glands. Likewise, in the higher vegetation, the leaves,
the roots, the buds, the seed, etc., often contain principles or alka-
loids totally different from the other parts. And the same particle
or cellule can assume various forms according to its stage of deve-
lopment, its surroundings, or nourishing pabulum.

Furthermore, the virulence of bacteria may decrease or disappear
in certain cultures ; increase or reappear in others. Now, if the
virulence constitutes for itself a truly specific character at every
step, we shall have to admit, in those microbes, changes of species;
and thus, in order to defend the true and well-thought pleomor-
phism, we must necessarily fall into an illimited and unlikely one.

However, referring to the six species of micro-organisms
admitted by Miller in the cavity of the mouth, we, with due
respect for the author, cannot abandon the opinion (which,
although old, is not ours) of the fundamental unity of all
these forms, and their derivation from a single species, the Lep-

* Miller, die Mikroorganistneil dej- Mundhohl, etc., 1889, pp. 43 — 75.

AND CONTENTS OF THE MOUTH. 175

tothrlx buccalis of Robin \ of which, in the following section, we
will give our description in its principal biological phases. At
most, some doubt might be entertained- in regard to the Spirilla
or Spirochaeta, whether to hold them as a species, or belonging to
a distinct species ; but their relationship with Leptothrix was
recognised even by Zopf, who, on this point, wrote : " In certain
cases, the filaments (of Leptothrix), either on a given part or in all
their length, take a spiral shape, and the fragments of those fibres
form the Sptrillce, Vibriones, and SpirochcBtce,y ^'

Miller himself in mentioning his studies, made in 1883
upon those of Zopf, also admitted the derivation of the Spiro-
chcetce of the human mouth from the twisted threads of Lepto-
thrix, of which he gave a representation of the fragments in the
figures 13 to 20 of his plate; and, in the description of the
branching filaments of Leptothrix gigantea of the pig (Figs. 6 to 8)
and of the sheep (Fig. 9 to 12), he represented by the side of
straight filaments other vibrionic and spirillic ones.t

We have besides, by our observations, pointed out that the
Spirilla or SpirochcEta are constantly united with Leptothrix, even
in the infusion of potatoes and in stale water (in a warm atmo-
sphere). Later on, we shall see that they are also found in certain
urinary mucous flakes, always accompanied by vigorous fructifica-
tions of Leptothrix.

f Pathogenic Fungi of the Mouth.

We conclude this short extract by summing up the views given
by Miller in Chap. IX. of his work upon the experimental infec-
tions produced through the inoculation from certain microbes of
the mouth, or accidentally lodged in it.

The author begins by reminding us that the venomous property
of saliva was long before known when, in 1873, Wright and
Senator used it for the purpose of inoculation with deadly result.
It was suspected that the poisonous effect depended upon a chemi-
cal cause. Moriggia and Marchiafava, in 1878, inoculated with
the saliva of children dead from rabies. The first who

* Zopf, loc. cii., page 80.
t Miller, Article ^zV. 1883, pp. 223—24.

176 BACTERIA IN THE SPUTA

attributed to bacteria the venomous action of the saliva or
sputa were Eaynaud and Lannelongue, in 1891. The rabbits
that were inoculated with the saliva of a boy who died of
rabies, died ; whilst the inoculations with the blood or the buccal
mucus were harmless. Pasteur saw two rabbits die after inocula-
tion with the same saliva ; and the cultivated microbes exhibited
the shape of dumb-bell bacteria in a gelatinous capsule. He then
believed he had discovered the cause of hydrophobia ; but Cohn-
heim, having noticed the rapidity of the infection, qualified it for
septicaemia.

After these first experiments, Vulpian produced the same infec-
tion by inoculating with the normal saliva ; and, in the blood of
the inoculated animals, Rochefontaine and Arthaud detected
microbes quite identical with the above-named. Sternberg and
Claxton confirmed the observations of Vulpian ; but Grififin
demonstrated that the saliva of the parotides, gathered separately,
is harmless ; so that the infection is to be attributed to secondary
products of decomposition, formed in the buccal cavity. Gaglio
and De Mattei held the same view, and noticed that the saliva
became harmless after boiling.

Fraenkel in 1884 confirmed anew the observations of Vulpian.
He found that dogs were more receptive, the mice less so, and
still less guinea-pigs. Dogs, pigeons, and fowls were refractory.

Miller obtained identical inoculations with the excretion of a
woman affected with micosis of the tonsils. He separated after-
wards from a decayed root five fungi, of which one was distinctly
pathogenous.

Klein and others studied the venomous action of groups of
microbes of the human sputa, so that in late years pathogenic
properties were gradually attributed to a considerable number of
bacteria.

Pathogenic Fungi not Cultivable.— The author repeats here
what has already been said of the primary microbes of the mouth,
to demonstrate that Spirillum sputige?iu?n and Spiroc/icete dentium
are especially not cultivable. Kreibohm found in the patina of
the tongue two pathogenic bacteria unfit for cultivation in any
artificial medium whatever. Miller, with fungi from a gangrenous
pulp of the teeth, obtained a gangrenous product for re-inoculation.

AND CONTENTS OF THE MOUTH. 177

Pathogenic Fungi Cultivable.— (<3;) Micrococcus of the sputum^
Septiccemia (Figure 96 of Miller). — This is the same bacterium
that Pasteur and others obtained from healthy and pathological
sputa. Klein was the first to cultivate it. It results in oval cocci,
diplococci, and capsulated chains identical with Pfietwiococcus.
Subcutaneous injections with its cultures produce septicaemia and
death in 24 — 36 hours. Even the blood of animals inoculated is
totally infected ; but the infection, once overcome, is contracted
no more. Its virulence is attenuated by cultures in milk. This
bacterium (continues Miller), lodging constantly in the human
mouthy passes from there into the pulmonary tubes ; so that the
uncleanliness of the mouth would be the real predisposing
condition to pneumonia, in so far as it allows the diplococci in
question, deposited there from the air, to multiply. From those
views to ours, to the entirely secondary propagation of such bac-
teria in the pulmonary products, there is but one step. (See
Section 4 of Memoir on Whooping-cough.)

ip) Bacillus crassus sputigenus (Fig. 97 of Miller, from the
blood of a mouse). — This bacterium was found by Kreibohm once
on the patina of the tongue and twice in the liquids of the mouth;
it is longer than it is broad, but often shorter in its younger articu-
lations ; resists Gram's method ; sporifies through heat. Mice,
inoculated even with small quantities, die in forty-eight hours,
exhibiting myriads of bacteria in their liver and blood. A copious
injection of it into the veins kills rabbits and dogs in from
three to ten hours from gastro-enteritis.

{c) Staphylococcus pyogenus albus and aureus^ and Streptococcus
pyogenus. — These bacteria, held as promoters of suppuration, are
brought from outside into the mouth, where they seem to find a
fit soil. Black, upon ten specimens of buccal liquids and scrap-
ings from the tongue, found seven times Staphylococcus pyogenus
aureus — four times the albus and three the Streptococcus^ which he
believes with a careful search can always be found. Vignal never
came across the true streptococcus ; seldom found the two staphi-
lococci. Netter, upon 127 specimens, found only seven times the
Staphilococcus pyogenus aureus. Miller also rarely found these
micrococci.

id) Micrococcus tetrageftus (Fig. 98 of Miller). — This micrococ-

178 BACTERIA IN THE SPUTA

cus, relatively frequent, was first found by Koch and Gaffky in the
cavities of a consumptive subject ; it is more frequent in tubercu-
losis. Biondi found it in three cases out of five. It is in the
shape of cocci disposed two by two or four by four ; with gelatin-
ous matter interposed, it does not liquefy the gelatine. White
mice and guinea pigs inoculated with its cultures die in from three
to ten days; those inoculated with sputa perish in from four to
eight days. Their blood and their organs are infested with micro-
cocci.

Fungi of Biondi. -This investigator has isolated from the
mouth five different pathogenic bacteria, including the Micrococcus
tetragenns above-mentioned. The four others are : — [e) a Bacillus
salivarius septicus, rather frequent ; (f) a Coccus salivarius septicus,
obtained in a single case only from a woman affected with a serious
septicaemia in her confinement ; (g) a Sti-eptococcus septicus^ similar
to that of erysipelas phlegmon and puerperal Metrilis ; (h) a
Staphylococcus salivarius pyogenes^ found once in the sputum of a
scarlatinous quinsy.

The Fungi of Miller.— After many cultures and inoculations
from buccal liquids and dental gangrenous pulp, Miller observed
more serious effects from the inoculations of the pulp, even
in comparison with inoculations of cultures of the same pulp.
The effects were varied in different animals and according as the
inoculation was made under the skin or the peritoneum cavity.
The pathogenic fungi isolated by the author were : — (r) a Micro-
coccus Gengivce pyogenes (Fig. 99 of Miller), obtained from alveolar
pyorrhoea cocci that did not liquefy the gelatine ; {k) a Bacterium
Gengivce pyogenes (Fig. 100 of Miller), found with the former, in
the shape of bacteria four times longer than broad, apt to liquefy
the gelatine ; (I) a Bacillus Dentalis viridans (Fig. loi of Miller),
obtained from the decayed roots of teeth, in bacteria of irregular
forms; (m) a Bacillus FulpcB pyogenes [Y'lg. 102 of Miller), obtained
from the gangrenous pulps, in bacilli, frequently irregular, isolated,
linked together, or in small chains, even with eight articulations,
apt to liquefy the gelatine.'"

We cannot further describe these culture experiments. We

* Miller, loc. a'L, pp. 199 — 220.

AND CONTENTS OF THE MOUTH. 179

shall only remark that the pneumococci, or the exciters of salivary
septicaemia, being constantly found in the contents of the mouth,
are to be held, in our opinion, as one of the forms or phases of
the microphite or microphites of the mouth (zoogleic phases of
Billet). With regard to all the other bacteria we have just men-
tioned, it remains to be observed whether they are accidental —
i.e.^ proceeding from without— or normal, although modified in
their properties by variable conditions of pabulum or surroundings ;
and whether their numerous varieties are perhaps more apparent
than specific.

As regards the experimental inoculations, we shall simply notice
the fact that they introduce, under the skin, in the cavity, or in the
circulation, all at once, myriads of bacteria. A single centigramme
of culture or of polluted material may contain, on an average,
twenty-five billions of bacteria, as we have elsewhere demon-
strated: and twenty-five milliards inoculated in a mouse are as
fifty or a hundred triUions (Italian measure) inoculated in a man.
Is it wonderful if local or general effects may be produced from
the sudden irruption of such a mass of parasitical germs, even
though in themselves innocuous ? Nevertheless, that is not the
real question; the real question is whether the different kinds of
bacteria (probably belonging to the same species) have the power
of attacking, spojitedLud on their own account, the human economy;
and whether, even penetrating it from their media, in an infinitesi-
mal number (as is the case in the ordinary infectious diseases), can
they develop in the human species the same effects following upon
the inoculation of their elements on the brutes?

In other words, one is the receptivity through the natural pas-
sages and another through the continuous solutions ; one is the
slow, successive, and external action of a few germs, another that
of the sudden and internal mass of germs. Finally, one is the
receptivity of this or that animal species, and another that of the
human species. And all this is irrespective of the other more or
less questionable points, and especially of the query : If the mor-
bific action of the inoculations depends upon the bacteria, as
such, or upon the polluted matter in which they are suspended ;
or, it may be, upon their products of secretion and decomposi-
tion, as is at the present time generally argued.

180 BACTERIA IN THE SPUTA

But, leaving for the present those complex questions, I will
proceed to speak of the morphology and biology of Leptothrix.-''

§ IV.

REMARKS ON THE MORPHOLOGY AND BIOLOGY OF
THE LEPTOTHRIX BUCCALIS.

The Four Phases of Leptothrix and particularly the
Fructifications by Ears (Spic^).

First Phase. — The first phase of the Leptothrix is that of
a Bacterium or Bacillus, already described in the Memoir on
Whooping-cough and in the first paragraph of the present one.
This phase is common to all the other species of bacteria, but
which (at least in Leptothrix^ does not represent its whole cycle of
life, but only its primordial stage of immersed vegetation, or a
vegetation destined to propagate in liquid or semi-solid substrata
(media).

Second Phase. — Examining the cuticle of the tongue, stained
with gentian violet, we find there by preference the forms of the
second stage of life of this parasite — namely, that of chains,
bundles, and masses of intertwined filaments. We have already
said that in these preparations the buccal epithelia predominate ;
isolated filaments are found there, as well as many specimens of
large dumb-bell bacteria of the type/./, and/' (Fig. 2), and con-
spicuous masses of diplococci. These preparations show that the
large dumb-bell bacteria are derived from the diplococci, the two
original cocci linking together. The degrees of transition to be
observed there are many. The same chains are often surrounded

* Two fresh works were lately published on this argument : one by David
( Les Microbes de la bouche, precede d'une letire-preface de M. L. Pasteur),
a simple compilation ; the other by Billet ( Contributioi a delude de la
Morphologie et du developpeiiient des bacteriacees), the result of original re-
searches on the natural history of four species of micro-organisms {Cladolhrix
dichoto/na, Bacterium Balbiani, Bacterium osieophihun, and Leptothrix para-
sitica, a parasite of sea-weeds). We shall notice these works later on ; we may
at once say that not even these authors hint in the least to the SUPERIOR
PHASES of Leptothrix buccalis, after our type or other's.

AND CONTENTS OF THE MOUTH. 181

by similar masses of diplococci ; even the entanglements of the
type «, u, are not wanting (Fig. 2).

The chains belong to types c and d (Fig. 2), but are generally
longer, thick, branched off in bundles of 10 or 15, which take up
to three visual fields, and exactly represent the disposition of the
bundles of filaments. In the same chain small diplococci may
alternate with eUiptical bacteria and medium-sized dumb-bells — all
perfectly equal, which form the largest number.

In these we have been unable to find fructifications, so that
this second phase may be held as analogous to mycelium, or the
vegetation, of fungi, partly immersed, partly creeping.

Third Phase {Inc07?ipkfe aerial vegetation). — This is generally
met with in the tartar of the teeth. Its predominant elements are
the large filaments, often very long, bent, and re-united in bundles,
taking a brilliant colour with iodine ; and the stumps. I shall
not describe these well-known forms, having already done so in
speaking of the primary and secondary species of Miller.

I would rather point out some features, noticeable in a certain
number of these filaments, when I have the opportunity of finding
them isolated (especially in the unstained preparations), such
features not having been considered by previous authors.

The first is a division into two or three branches (Fig. 9),
which I think must be taken for a kind of radical system of this
microphite, for divisions are never detected towards its apex ; and,
at its opposite end, a swelling or head is noticed, which is a
proper form of points twined upwards (as in b). In a the filament
is broken towards the top and exhibits two long roots ; in b, there
are three hood-shaped roots. Both appear to be swollen at their
ends, like haustoria.

What can be the use of these barbs or roots, unless to obtain
a firm foundation in the ground ? And to what purpose is this
firm foundation, unless to support higher forms of vegetation ?

The other feature is that of the swelling, which we will call
apices or heads, being found at the top of the respective filaments,
as in b and <:, and these are of varied form, at times containing a
kind of nucleus. There are others which might be styled knotty,
being found along the filament ; of these we give no drawing, as
they are similar to the preceding ones.

182 BACTERIA IN THE SPUTA

With the above-mentioned stumps are intermixed almost all
the forms of bacteria, bacilli, spirilla, etc., besides a large number
of very varied small chains, after the types <:, d^ k, i, x, and x
(Fig. 2).

The larger size and the facility to colour of these masses and
stumps, with regard to fertile filaments, would depend, I think,
upon a very natural cause. The friction, removing the points of
the filaments and the fertile filaments, seems to impart a greater
development to the remaining stems in the sense of thickness ;
as, for instance, it happens in the pruning of trees, through the
retrocession of the ascending sap.

In the present case, the retrocession of the germinal matter
would be the cause of the consecutive increase of the sheath and
of the gemmules contained in it. Thus might be easily explained
the appearances, so various, of the stumps and their fragments,
compared with the fertile filaments ; appearances which induced
Miller to make of residual filaments two distinct species, under
the name of Leptothrix buccalis maxima and Bacillus buccalis
maximus, in opposition to our fertile filaments, which for Miller
constitutes a third species, the Leptothrix inno??ii?iata.

It remains, then, to be seen whether the longer filaments, sunk
down and intertwined, of Bacillus buccalis maxifnus (Fig. 13 of
Miller) may not concur, with the above described chains, to form
that kind of mycelium or creeping vegetation, upon which is based
the aerial vegetation of this microphite.

From the tiny islands of the stumps in question, prepared in
the manner already described in Section 2, spring at last the fruc-
tifications. The bigger filaments, that we would call woody, gra-
dually become thinner and pale, showing in their interior countless
granules or parietal gemmules. These are the fertile filaments.
They may spring either from the proper filaments, with continuous
contour, or from the little chains after type d (Fig. 9), which are
seen occasionally on the top of those filaments ; and in this last
case, instead of a gradual thinning, may abruptly pass from the
chain to the fertile filament, as shown in the figure.

It is by no means uncommon to find parietal gemmules, as
Robin mentions the circumstance, and gives a first drawing in
Fig. 2h of his volume of 1853, magnified to 800 diameters.*

* Robin, Hist. Nat, des Vegetaux, etc., 1853. (See Bibliography.)

AND CONTENTS OF THE MOUTH. 188

Fourth Phase {Completed Aerial Vegetation: Fructification). —
In Figs. 10 — 13 ^^6 reproduced four specimens of fructifications,
taken from the pati?ia dentaria. In Fig. 10 are seen three isolated
"ears" (spices), stained with gentian violet; in Fig. 11, a tuft,
caught as the bird flies, stained with weak methyl violet ; in Fig.
12, a part of a more vigorous tuft, seen in profile, stained with
weak fuchsine ; and in Fig. 13, two fructifications, set on the same
tiny island of materia alba, stained with solution of iodine. The
Figures 10, 11, and 13 are drawn magnified to 1,250 diameters,
and the Fig. 12 to 850 diameters.

The fertile filaments are at times partially straight, as in Fig.
10; at times bent (even occasionally tortuous, as in Fig. 13), and
are sometimes wanting, because the fructifications have been
carried away by mechanical force, although grouping together, as
in Fig. 12. In Fig. 10 are seen, in a, a, the gemmules of reserve
adhering to the walls ; in b are found the little spores properly
lodged ; but in b' we notice only five, the others having dropped.
In c the penultimate articulations of the stalk appear older and
woody ; the last is granular, like the two articulations on the apex
of the younger filament, d.

The sporules, very small, round, brilliantly coloured, show
themselves in three vertical rows in all the specimens without
exception ; i.e., they never appear in two rows, whence we may
infer that they are, in fact, disposed in six longitudinal lines (or
series), for, if they w^ere only in four or five, they should, at times,
exhibit only two visible rows.

In turning the micrometer screw, the cylindrical relief of the
" ears " appear manifest, for at a higher focus the sporules of the
middle row are better seen, and at a low focus those of the lateral
rows. In several specimens, especially when coloured with picric
acid, we can detect the prolongation of the stem into the interior
of the ear ; but it is not so with aniline colours, which render the
viscid substance (in which the sporules are suspended) opaque,
staining it with a weaker tint. But if, in the preparation, we sub-
stitute glycerine for water, the stalk, a long time afterwards,
reappears distinctly in all its length.

At any rate, the movements given to the preparation with the
thumbs show that the stalk and the " ear " form a continuous

184 BACTERIA IN THE SPUTA

whole ; then we observe the " ears " on the top vibrating like the
ears in a field of wheat.

It may be objected that the sporules are not immediately
grafted on the stalk or fertile filament, but are distant from it ; it
must, however, be taken into consideration that the distance
between the sporules and the internal filament is not, in fact,
greater than that which is constantly seen between the articula-
tions of the single chains of bacteria, which, as it is scientifically
ascertained, are generated one from another. Perhaps a connec-
tion exists between them, through threads or ligaments, not dis-
cernible by the optical power at our command.*

We cannot even suppose that the sporules are simply adhering
to the filament through external action (due to the lowering or
sinking, so to speak, of the filaments themselves into the granular
masses), because a simple mechanical incrustation would not
explain the regular straight line of the sporules in six longitudinal
rows, nor their perfect similarity of volume and shape.

The incrustation would bring a medley of cocci and bacteria,
of varied type and size, irregularly mixed up. Besides, we shall
observe productions of these "ears" (and even more conspicuous)
in the sputa, without any trace of bed or granular mass on which
the filaments might have become incrusted from the outside.

The length of ears is frequently considerable, especially in
those detached from the matrix, which at times, with their stem,
occupy all the visual field. The more conspicuous specimens
(Fig. 1 6) have been found in the pulmonary sputum, where the

* When we presented this Memoir, we promised in a note to resume the
study of ^' ears'' in detail, with more powerful objectives. Now Messrs. Bezu,
Hausser, and Co. have succeeded in constructing a new objective with homo-
geneous immersion, of i/25th inch. With this power we have been able to
detect, in the most evident manner, the peduncles or engrafted threads of the
sporules on the principal stalk. With the new grand model (No. VII.) of the
same opticians, furnished with an Abbe condenser of the numerical aperture,
I -40, by using oblique light, and by turning the stage of the microscope, or
substituting a dark diaphragm for the ordinary one, the disposition of the spo-
rules in six longitudinal lines is fully confirmed. We shall treat this point
again later ; but from this moment we think it is better to give the name of
" bunches of grapes" instead of that of ''ears'' (to indicate the fructifications
of Leptothrix)^ as they really are such.

AND CONTEXTS OF THE MOUTH. 185

longest were one-sixth of a millemetre high, equivalent to the
thickness of a thin cover-glass, as in the Figs./, g of the figure.

The colouration of the ears in question with carmine, pro-
tracted even for weeks in a watch-glass, gave no satisfactory results.
With methyl violet the specimens appear less transparent ; in other
respects, they are like those treated with gentian violet. In Fig.
1 1 one may be observed, in which the ears are in the direction of
the visual axis. With fuchsine the most fine and brilliant coloura-
tions are obtained, as shown in the specimen caught in profile,
represented in Fig. 1 2, after being immersed for a few minutes.

In the uncoloured preparations, the ears are hardly or not at
all discernible, so that they could not be detected by him who
should ignore their existence ; the sporules being, in their natural
state, transparent and nearly invisible ; but these preparations are
helpful to him who knows them, in so far as they aid to detect,
on the outline of the mass, a larger number of ears which have
not been spoiled or carried away by the manipulations, or hardened
and consequently become brittle.

Anyhow, the flexibility of the ears is preserved even in the
colourings with the solution of iodine, not acidulated, or with
picric acid. The sporules appear distinctly with the solution of
iodine (Fig. 13); but with picric acid the colouring is diffused and
pale, although the pale tint is useful in its turn in disclosing at
one time a larger number of fructifications, without rendering any
of them opaque.

Here we shall stop awhile to consider the great affinity of those
sporules through the aniline colours ; which affinity brings them so
closely to the tubercular bacilli as to make us suspect that the
single articulations of such bacilli proceed from the sporules,
which, having dropped, transplant themselves into the buccal epi-
thelia and the air-passages, and grow like beaded forms. We were
led to that supposition from the following fact : — In the colourings
with fuchsine of the patina dentaria, which last a very short time,
the central portion of many masses remains uncoloured. How
great was our surprise in seeing, some time afterwards, in those
uncoloured areas, minute red lines, perfectly similar to the tuber-
cular bacilli ! Then those coloured lines gradually increased, and
we saw the summits of ears developing, as mounds, brilliantly

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. o

186 BACTERIA IN THE SPUTA

coloured, in a clear area. This fact is to be attributed to the
subsequent action of the colouring matter.

Besides the bacilli of Koch in rosaries, we have others in small
rods or filaments containing granules or vacuoli, as in Fig. i of the
work of Cornil and Babes, etc. These rods appear more clearly
when stained by Gram's method — viz., with double colouring, first
with gentian violet and then with solution of iodine. Now, the
fragments and slender stems of Leptothrix, in the patina de?ttarta,
behave likewise. If the solution of iodine should be used first,
the successive colouring with gentian violet does not succeed; but
if we colour with violet, as usual, mounting the preparation when
fresh, and then introducing by capillarity the solution of iodine,
the violet colouring becomes dark blue and the small rods of
Leptothrix appear very clearly.

On another occasion I shall treat those questions relating to
the finding and colouring of the tubercular bacilli.

Productions by Points (Male Organs ?)

I have already said that such productions or pseudo inflores-
cences are scanty, so that we must seek them patiently in the
preparation. They have, however, the advantage of showing
themselves clearly, even without colouring. It is absolutely neces-
sary to examine the patina dentaria of persons who have fasted
and who are not in the habit of cleaning their teeth, otherwise we
may not find these productions. The preparation should not be
pressed too much, in order to avoid the disintegration of the spe-
cimens. They are easily recognised with an objective, No. 8 of
Hartnack. The above-mentioned difficulties indicate why such
forms have not been considered by previous investigators.

In Fig. 14 are shown three of these productions in the natural
state, taken from the pati?ia dentaria, and magnified to 690 dia-
meters. They are formed of one or more internal stocks and a
considerable number of points which surround them, like the
horsehairs of a cylindrical brush. In a the production rises upon
a multiple stalk, formed of a bundle of filaments apparently
broken off. The stalk itself is crowded with small points near the
trifurcation ; the three small divided branches bear longer points

AND CONTENTS OF THE MOUTH. 187

up to the top ; but the right one is also subdivided in two second-
ary tiny branches. In h is drawn an isolated pseudo inflorescence,
formed of small and medium points, like the small branches of the
preceding specimen. In <r, on the contrary, is seen a production
broken on the top, formed of small, medium, and large points ;
the small points similar to the preceding ones ; the large ones
totally similar to the pointed and spindle-like bacilli of type e
(Fig. 5), of which, for comparison's sake, we have reproduced one
in its natural state in d (Fig. 14), magnified to 1,250 diameters.
Most of the small points resemble the Virgula bacilli of type h
(Fig. 5) ; some, however, look like the spermatozoa of type H
(same figure), having at one end a kind of small head, according
to the degree to which they are magnified.

In Fig, 15 is seen a portion of a small branch, coloured with
the solution of iodine, magnified to 2,500 diameters. Points of
various size and shape are set in it, which, like the central rod,
contain clear spaces or uncoloured empty ones. If it were not too
bold a supposition, I should be inclined to suggest that the three
small points are not adhering to the central rod, but are fulfilling
their functions upon it, and perhaps even upon the bacillus which
adheres to it lower down — a quid simile with the act of fecundation.

I repeat that it is not my intention to pronounce on the nature
of these productions h^ points or pseudo-inflorescences, that being
a subject for micetologists. I have only wished to describe facts
resulting from my own observations. However, I cannot help
noting the very extraordinary mobility exhibited by those points^
large and small, dropped from the stalks or branches above
described.

Those movements are better detected in uncoloured prepara-
tions, mounted in simple distilled water, in which they are pre-
served longer (even from day to day), especially in the minute
Virgula bacilli ; so that I suggest to those who will verify this part
of my observations, not to use any tint at all. The stains used,
particularly the aniline colours, seem to have a poisonous effect
upon those bacilli, or at least exert a lethargic action on their
motility. In the largest or spindle-like bacilli of type d (Fig. 14)
the movements are those of translation, so that they fully justify
the name of Bacillus tremulusy given to them by Rappin, if that

188 BACTERIA IN THE SPUTA, ETC.

name does not imply a separate specific entity. We notice that
those bacilU vibrate not only sidewise, like fishes, but flash here
and there with a rapid translatory motion, dashing first upon one
tiny island and then (after a pause) upon another, or disappearing
from the visual field. It is impossible not to recognise in those
motions the character of vital movements, either voluntary or
teleological j and excluding the first hypothesis, which would lead
us to the ani77ialculcB of Leeuwenhoek, Ficinus, and Klencke,
there only remains 07ie external purpose to this bacilli, which is
directed to the performance of one function. That function can
only be an important one, considering that those motions are the
highest and most persisting manifestation of life exhibited by
buccal microbes. Now, what more important function than that
of fecundation ? *

The movements of the Virgula bacilli of type // (Fig. 5) are
generally undulating and serpentine ; but they have also a trans-
latory one, as we have suggested before.

In conclusion, we may suppose that those points, or so-called
bacilli, perform a function similar to that of spermatia or anthero-
zoids of various fungi and sea-weeds (Alg^). In such hypotheses
the absolute sterility of their cultures would be wholly explained,
being quite natural (as before suggested) that simple male organs
should not be able to reproduce by themselves alone. It remains
to be seen whether these productions by points have any relation-
ship with the bacillus n (Fig. 2 to the left below), a large bacillus
veined through its length, which contains, as in germ, slender and
short lineal bacilli towards the inferior end, so that we should be
inclined to compare it with a spermogene or antherid.\

We have hitherto dealt with productions by points^ in their
higher phase ; but near these we find other less developed forms,

* In the quoted article of Dowdeswell, to our surprise, we find that he
entertains doubts upon the nature (whether vegetal or animal) of the Cholera
bacillus. See Lancet, 1890, Vol. I., loc. cit., p. 1422.

t The spindle-like and Virgula bacilli of the mouth closely resemble, in
shape and size, the spermatia of the Sphcerella sentina, of the Fu?nago salicitta,
of the Apiosporiu7n citri, etc. The spermatia were considered, since 1877, as
male organs, when Cornu noticed that some of them were germinating by
themselves, so that their nature would be still uncertain.

THE SOLAR SYSTEM. 189

supported likewise by one or more internal stems and enveloped
in a mass of very minute lineal germs, quite similar to those con-
tained in 71 (same figure). Such lineal germs, engrafted in square
on the stalks, resemble spindle-like, serpentine, or Virgula bacilli
in formation, so that the whole may be taken for the first stage of
the pseudo inflorescences, or productions by points, already des-
cribed. Owing to the difficulty of reproducing them faithfully, we
have omitted their graphic representation in the Plate.

(To be continued.)

®n tbe flDagnitube of tbe Solar Sigetem/'^

By W. Harkness (Washington).

NATURE may be studied in two widely different ways. On
the one hand we may employ a powerful microscope which
will render visible the minutest forms and limit our field of
view to an infinitesimal fraction of an inch situated within a foot
of our own noses ; or, on the other hand, we may occupy some
commanding position, and from thence, aided by a telescope, we
may obtain a comprehensive view of an extensive region. The
first method is that of the specialist, the second is that of the phi-
losopher ; but both are necessary for an adequate understanding of
nature. The one has brought us knowledge wherewith to defend
ourselves against bacteria and microbes which are among the most
deadly enemies of mankind, and the other has made us acquainted
with the great laws of matter and force upon which rests the whole
fabric of science. All nature is one, but for convenience of clas-
sification we have divided our knowledge into a number of sciences
which we usually regard as quite distinct from each other. Along
certain lines, or, more properly, in certain regions, these sciences
necessarily abut on each other, and just there lies the weakness of
the specialist. He is like a wayfarer who always finds obstacles
in crossing the boundaries between two countries, while to the

* Part of the Address delivered before the American Association for the
Advancement of Science at its Brooklyn meeting, Aug. i6, 1894, by the
retiring President, Professor Harkness. From Science.

190 ON THE MAGNITUDE OF

traveller who gazes over them from a commanding eminence the
case is quite different. If the boundary is an ocean shore there
is no mistaking it ; if a broad river or a chain of mountains it is
still distinct ; but if only a line of posts traced over hill and dale,
then it becomes lost in the natural features of the landscape, and
the essential unity of the whole region is apparent. In that case,
the border-land is wholly a human conception of which nature
takes no cognizance, and so it is with the scientific border-land to
which I propose to invite your attention this evening.

To the popular mind there are no two sciences further apart
than astronomy and geology. The one treats of the structure and
mineral constitution of our earth, the causes of its physical fea-
tures and its history, while the other treats of the celestial bodies,
their magnitudes, motions, distances, periods of revolution,
eclipses, order, and of the causes of their various phenomena.
And yet many, perhaps I may even say most, of the apparent
motions of the heavenly bodies are merely reflections of the
motions of the earth, and in studying them we are really studying
it. Furthermore, precession, nutation, and the phenomena of the
tides depend largely upon the internal structure of the earth, and
there astronomy and geology merge into each other. Neverthe-
less the methods of the two sciences are widely different, most
astronomical problems being discussed quantitatively by means of
rigid mathematical formulae, while in the vast majority of cases
the geological ones are discussed only qualitatively, each author
contenting himself with a mere statement of what he thinks.
With precise data the methods of astronomy lead to very exact
results, for mathematics is a mill which grinds exceeding fine ; but,
after all, what comes out of a mill depends wholly upon what is
put into it, and if the data are uncertain, as is the case in most
cosmological problems, there is little to choose between the
mathematics of the astronomer and the guesses of the geologist.

If we examine the addresses delivered by former presidents of
this Association, and of the sister — perhaps it would be nearer the
truth to say the parent — Association on the other side of the
Atlantic, we shall find that they have generally dealt either with
the recent advances in some broad field of science, or else with
the development of some special subject. This evening I propose

THE SULAR SYSTEM. 191

to adopt the latter course, and I shall invite your attention to the
present condition of our knowledge respecting the magnitude of
thesolar system, but in so doing it will be necessary to introduce
some considerations derived from laboratory experiments upon the
luminiferous ether, others derived from experiments upon ponder-
able matter, and still others relating both to the surface pheno-
mena and to the internal structure of the earth, and thus we shall
deal largely with the border-land where astronomy, physics, and
geology merge into each other.

The relative distances of the various bodies which compose
the solar system can be determined to a considerable degree of
approximation with very crude instruments as soon as the true
plan of the system becomes known, and that plan was taught by
Pythagoras more than five hundred years before Christ. It must
have been known to the Egyptians and Chaldeans still earlier, if
Pythagoras really acquired his knowledge of astronomy from them
as is affirmed by some of the ancient writers, but on that point
there is no certainty. In public Pythagoras seemingly accepted
the current belief of his time, which made the earth the centre of
the universe ; but to his own chosen disciples he communicated
the true doctrine that the sun occupies the centre of the solar
system, and that the earth is only one of the planets revolving
around it. Like all the world's greatest sages, he seems to have
taught only orally. A century elapsed before his doctrines were
reduced to writing by Philolaus of Crotona, and it was still later
before they were taught in public for the first time by Hicetas, or,
as he is sometimes called, Nicetas, of Syracuse. Then the fami-
liar cry of impiety was raised, and the Pythagorean system was
eventually suppressed by that now called the Ptolemaic, which
held the field until it was overthrown by Copernicus, almost two
thousand years later. Pliny tells us that Pythagoras believed the
distances to the sun and moon to be respectively 252,000 and
12,600 stadia, or, taking the stadium at 625 feet, 29,837 and 1,492
.English miles ; but there is no record of the method by which
these numbers were ascertained.

After the relative distances of the various planets are known,
it only remains to determine the scale of the system, for which
purpose the distance between any two planets suffices. We know

192 ON THE MAGNITUDE OF

little about the early history of the subject, but it is clear that the
primitive astronomers must have found the quantities to be mea-
sured too small for detection with their instruments, and even in
modern times the problem has proved to be an extremely difficult
one. Aristarchus of Samos, who flourished about 270 B.C., seems
to have been the first to attack it in a scientific manner. Stated
in modern language, his reasoning was that when the moon is
exactly half full, the earth and sun as seen from its centre
must make a right angle with each other, and by measuring the
angle between the sun and moon, as seen from the earth at that
instant, all the angles of the triangles joining the earth, sun, and
moon would become known, and thus the ratio of the distance of
the sun to the distance of the moon would be determined.
Although perfectly correct in theory, the difficulty of deciding
visually upon the exact instant when the moon is half full is so
great that it cannot be accurately done even with the most power-
ful telescopes. Of course, Aristarchus had no telescope, and he
does not explain how he effected the observation, but his conclu-
sion was that at the instant in question the distance between the
centres of the sun and moon, as seen from the earth, is less than
a right angle by i/3oth part of the same. We should now express
this by saying that the angle is 87 degrees, but Aristarchus knew
nothing of trigonometry, and in order to solve his triangle he had
recourse to an ingenious, but long and cumbersome geometrical
process which has come down to us, and afi"ords conclusive proof
of the condition of Greek mathematics at that time. His conclu-
sion was that the sun is nineteen times further from the earth than
the moon, and if we combine that result with the modern value of
the moon's parallax, viz., 3, 422*38 seconds, we obtain for the solar
parallax 180 seconds, which is more than twenty times too great.

The only other method of determining the solar parallax
known to the ancients was that devised by Hipparchus about 150
B.C. It was based on measuring the rate of decrease of the dia-
meter of the earth's shadow cone by noting the duration of lunar
eclipses, and as the result deduced from it happened to be nearly
the same as that found by Aristarchus, substantially his value of
the parallax remained in vogue for nearly two thousand years, and
the discovery of the telescope was required to reveal its erroneous

THE SOLAR SYSTEM. 193

character. Doubtless this persistency was due to the extreme
minuteness of the true parallax, which we now know is far too
small to have been visible upon the ancient instruments, and thus
the supposed measures of it were really nothing but measures of
their inaccuracy.

The telescope was first pointed to the heavens by Galileo in
1609, but it needed a micrometer to convert it into an accurate
measuring instrument, and that did not come into being until 1639,
when it was invented by Wm. Gascoigne. After his death, in
1644, his original instrument passed to Richard Townley, who
attached it to a fourteen-foot telescope at his residence in Townley,
Lancashire, England, where it was used by Flamsteed in observing
the diurnal parallax of Mars during its opposition in 1672. A
description of Gascoigne's micrometer was published in the Philo-
sophical Transactions in 1667, and a little before that a similar
instrument had been invented by AuzouJ in France, but observa-
tories were fewer then than now, and so far as I know J. D. Cassini
was the only person beside Flamsteed who attempted to determine
the solar parallax from that opposition of Mars. Foreseeing the
importance of the opportunity, he had Richer despatched to
Cayenne some months previously, and when the opposition came
he effected two determinations of the parallax ; one being by the
diurnal method, from his own observations in Paris, and the other
by the meridian method from observations in France by himself,
Romer, and Picard, combined with those of Richer at Cayenne.
This was the transition from the ancient instruments with open
sights to telescopes armed with micrometers, and the result must
have been little short of stunning to the seventeenth century
astronomers, for it caused the hoary and gigantic parallax of about
t8o seconds to shrink incontinently to ten seconds, and thus
expanded their conception of the solar system to something hke
its true dimensions. More than. fifty years previously Kepler had
argued from his ideas of the celestial harmonies that the solar
parallax could not exceed 60 seconds ; and a little later Horrocks
had shown on more scientific grounds that it was probably as
small as 14 seconds, but the final death-blow to the ancient values
ranging as high as two or three minutes came from these observa-
tions of Mars by Flamsteed, Cassini, and Richer.

194 ON THE MAGNITUDE OF

Of course, the results obtained in 1672 produced a keen desire
on the part of astronomers for further evidence respecting the true
value of the parallax, and as Mars comes into a favourable position
for such investigations only at intervals of about sixteen years,
they had recourse to observations of Mercury and Venus. In
1677 Halley observed the diurnal parallax of Mercury, and also a
transit of that planet across the sun's disc, at St. Helena, and in
1 68 1 J. D. Cassini and Picard observed Venus when she was on
the same parallel with the sun ; but although the observations of
Venus gave better results than those of Mercury, neither of them
was conclusive, and we now know that such methods are inaccu-
rate even with the powerful instruments of the present day.
Nevertheless, Halley's attempt by means of the transit of Mercury
ultimately bore fruit in the shape of his celebrated paper of 17 16,
wherein he showed the peculiar advantages of transits of Venus
for determining the solar parallax. The idea of utilising such
transits for this purpose seems to have been vaguely conceived by
James Gregory, or perhaps even by Horrocks ; but Halley was the
first to work it out completely, and long after his death his paper
was mainly instrumental in inducing the governments of Europe
to undertake the observations of the transits of Venus in 1761 and
1769, from which our first accurate knowledge of the sun's dis-
tance was obtained.

Those who are not familiar with practical astronomy may
wonder why the solar parallax can be got from Mars and Venus,
but not from Mercury, or the sun itself. The explanation depends
on two facts. Firstly, the nearest approach of these bodies to the
earth is for Mars 33,870,000 miles, for Venus 23,654,000 miles,
for Mercury 47,935,000 miles, and for the sun 91,239,000 miles.
Consequently, for us Mars and Venus have very much larger
parallaxes than Mercury or the sun, and of course the larger the
parallax the easier it is to measure. Secondly, even the largest of
these parallaxes must be determined within far less than one-tenth
of a second of the truth, and while that degree of accuracy is
possible in measuring' short arcs, it is quite unattainable in long
ones. Hence, one of the most essential conditions for the suc-
cessful measurement of parallaxes is that we shall be able to com-
pare the place of the near body with that of a more distant one

THE SOLAR SYSTEM. 105

situated in the same region of the sky. In the case of Mars that
can always be done by making use of a neighbouring star, but
when Venus is near the earth she is also so close to the sun that
stars are not available, and consequently her parallax can be satis-
factorily measured only when her position can be accurately
referred to that of the sun, or, in other words, only during her
transits across the sun's disc. But even when the two bodies to
be compared are sufficiently near each other, we are still embar-
rassed by the fact that it is more difficult to measure the distance
between the limb of a planet and a star or the hmb of the sun,
than it is to measure the distance between two stars, and since the
discovery of so many asteroids, that circumstance has led to their
use for determinations of the solar parallax. Some of these bodies
approach within 75,230,000 miles of the earth's orbit, and as they
look precisely like stars, the increased accuracy of pointing on
them fully makes up for their greater distance, as compared with
Mars or Venus.

After the Copernican system of the world and the New^tonian
theory of gravitation were accepted, it soon became evident that
trigonometrical measurements of the solar parallax might be sup-
plemented by determinations based on the theory of gravitation,
and the first attempts in that direction were made by Machin in
1729 and T. Mayer in 1753. The measurement of the velocity
of light between points on the earth's surface, first effected by
Fizeau in 1849, opened up still other possibilities, and thus for
determining the solar parallax we now have at our command no
less than three entirely distinct classes of methods which are
known respectively as the trigonometrical, the gravitational, and
the photo-tachymetrical. We have already given a summary
sketch of the trigonometrical methods, as applied by the ancient
astronomers to the dichotomy and shadow cone of the moon, and
by the moderns to Venus, Mars, and the asteroids, and we shall
next glance briefly at the gravitational and photo-tachymetrical
methods.

>!< H« * ^ *

The theory of probability and uniform experience alike show
that the limit of accuracy attainable with any instrument is soon
reached ; and yet we all know the fascination which continually

196 ON THE MAGNITUDE OF

lures us on in our efforts to get better results out of the familiar
telescopes and circles which have constituted the standard equip-
ment of observatories for nearly a century. Possibly these instru-
ments may be capable of indicating somewhat smaller quantities
than we have hitherto succeeded in measuring with them, but
their limit cannot be far off because they already show the disturb-
ing effects of slight inequalities of temperature and other uncon-
trollable causes. So far as these effects are accidental, they
eliminate themselves from every long series of observations, but
there always remains a residuum of constant error, perhaps quite
unsuspected, which gives us no end of trouble. Encke's value of
the solar parallax affords a fine illustration of this. From the
transits of Venus in 1761 and 1769 he found 8"58 seconds in
1824, which he subsequently corrected to 8 '5 7 seconds, and for
thirty years that value was universally accepted. The first objec-
tion to it came from Hansen in 1854, a second followed from Le
Verrier in 1858, both based upon facts connected with the lunar
theory, and eventually it became evident that Encke's parallax was
about one-quarter of a second too small.

Now, please observe that Encke's value was obtained trigono-
metrically, and its inaccuracy was never suspected until it was
revealed by gravitational methods, which were themselves in error
about one-tenth of a second and required subsequent correction
in other ways. Here, then, was a lesson to astronomers who are
all more or less specialists, but it merely enforced the perfectly
well known principle that the constant errors of any one method
are accidental errors with respect to all other methods, and there-
fore the readiest way of eliminating them is by combining the
results from as many different methods as possible. However,
the abler the specialist the more certain he is to be blind to all
methods but his own, and astronomers have profited so little by
the Encke-Hansen-Le Verrier incidents of thirty-five years ago
that to-day they are mostly divided into two great parties, one of
whom holds that the parallax can be best determined from a com-
bination of the constant of aberration with the velocity of light,
and the other believes only in the results of heliometer measure-
ments upon asteroids. By all means continue the heliometer
measurements, and do everything possible to clear up the mystery

THE SOLAR SYSTEM. 197

which now surrounds the constant of aberration, but why ignore
the work of predecessors who were quite as able as ourselves ? If
it were desired to determine some one angle of a triangulation net
with special exactness, what would be thought of a man who
attempted to do so by repeated measurements of the angle in
question while he persistently neglected to adjust the net ? And
yet until recently astronomers have been doing precisely that kind
of thing with the solar parallax.

I do not think there is any exaggeration in saying that the
trustworthy observations now on record for the determination of
the numerous quantities which are functions of the parallax could
not be duplicated by the most industrious astronomer w^orking
continuously for a thousand years. How, then, can w^e suppose
that the result properly deducible from them can be materially
affected by anything that any of us can do in a lifetime, unless we
are fortunate enough to invent methods of measurement vastly
superior to any hitherto imagined ? Probably the existing obser-
vations for the determination of most of these quantities are as
exact as any that can ever be made with our present instruments,
and if they were freed from constant errors they would certainly
give results very near the truth. To that end we have only to
form a system of simultaneous equations between all the observed
quantities, and then deduce the most probable values of these
quantities by the method of least squares. Perhaps some of you
may think that the value so obtained for the solar parallax would
depend largely upon the relative weights assigned to the various
quantities, but such is not the case. With almost any possible
system of weights the solar parallax will come out very nearly
8 "809" — 0*005 7", whence we have for the mean distance between
the earth and sun 92,797,000 miles with a probable error of only
59,700 miles ; and for the diameter of the solar system, measured
to its outermost member, the planet Neptune, 5,578,400,000 miles.

It is the habit of centipedes to carry their young, clasped by
means of their legs, to all parts of the underside of the body,
though generally the young are clustered in dense masses. When
the young are thus bunched together, the body is coiled upon
itself at that part ; and the contrast between a centipede in this
position, says Mr. J. J. Quelch — who describes the centipede's
method in Nature — and a scorpion carrying her young upon her
back, just as a small oppossum does, is a marked one.

[ 198 ]

®n tbc Iprcparation of Zootb Scctlona/'

By W. B. Tolputt, L.D.S.

MY subject this evening is the grinding and preparing sec-
tions from hard tissue. I shall speak principally, if not
wholly, of the tissue with which I have most to do, and
with which I am most familiar, namely, a tooth. The enamel of
the tooth is the hardest tissue known in animal life ; and that
treatment which is most applicable to a tooth will apply also to a
bone, and, in fact, to all hard tissues.

There are two ways of obtaining tooth sections : one from
the tooth as it is, and the other by decalcification. It may be
necessary on occasions that one should know of a ready and
effective method of making sections of teeth or other hard tissues
when desirous of examining the internal structure. And by this
I mean, not a simple slice which may tell you anything or nothing,
but such a section as will show all and everything, regular and
irregular, which a good section should show. It is my desire to
give a few simple directions relative to what may be found in
most text books on histology, and, at the same time, to supple-
ment them with some practical suggestions which I have found
useful, and which may be of utility to any one wishing to make
sections of hard tissues, and of teeth in particular. If we take
any ordinary section of a tooth purchased at a dealer's, unless it
comes from a very expert and painstaking preparer, what do you
see ? Many times a specimen more or less transparent, with the
tubular structure of the dentine obliterated, or if not entirely
obliterated, covered by patches of translucency which mar the
general appearance as well as detract from the perfect utility of
the section. Fhe edges may be fractured and jagged, presenting
a very untidy appearance, and, taken altogether, giving but a very
meagre presentation of all the beautiful and instructive detail
which characterises a well-made specimen. Even in those sections
made with all care by ourselves, unless we adopt certain precau-
tions, we may have all this detail present in the earlier stage of a
section's existence, and yet be doomed to disappointment and

* A Paper read at the wSheffield Microscopical Society.

ON THE PREPARATION OF TOOTH SECTIONS, 199

annoyance in its examination after a year or two, by the gradual
disappearance of its tubular structure.

It was this experience which induced me to adopt various
expedients for obviating this annoying result, and although my
subject may be considered by some as well-worn, and as well
threshed out, I am hopeful enough to think that, by describing
the methods I adopt, I may perhaps be the means of assisting
some to attain results which will be regarded in after years with
satisfaction. I wish to be very plain and practical, therefore, if
ray communication appears somewhat of the character of the
cookery book of recipes, I hope your pardon will be extended to
me. Cookery books, although perhaps not the highest class of
literature, are nevertheless very useful in their results, and are
therefore not to be thoroughly despised.

Text books, in treating of this subject, advise first that "thin
slices should be cut from the tooth with a saw." Now^, however
desirable it may be to cut a tooth into as many sections as possible
in order to be enabled to trace the various phases of structural
change throughout its extent, I think I need not remind those
who may have attempted this method of the numbers of saws
broken, to say nothing of those blunted and worn out in cutting
through the enamel of one tooth. A lapidary's wheel has also
been recommended for cutting the rough sections. This would
cut but few sections out of many teeth, the number of sections
depending upon the thickness of the wheel used ; and, further-
more, we may not possess lapidary wheels. With care, two or
three sections may be cut from a tooth by first cutting through the
enamel by wetting a new thin gold file with turpentine and soft
soap, or turpentine and camphor, and then using a broad frame
saw for cutting through the dentine. There is n'o difficulty after
the enamel is passed. It may oftentimes be grooved by a thin
corundum wdieel on the lathe, and the section cut by the saw
afterwards. The plan I adopt may be a very wasteful one, but
till we get a ready means of cutting through the enamel, I am
afraid I must continue to recommend and to adopt it.

I take a tooth and hold it against the side of a revolving fine
corundum wheel till one side is ground flat ; then polish that
side to the most perfect polish it is capable of receiving on a

200 ON THE PREPARVTION OF TOOTH SECTIONS.

piece of buff leather with some putty powder on it. Afterwards,
take a piece of stout glass, put a little old, and consequently
tough, Canada balsam on it, warm it, and spread it a little larger
than your section. Let the balsam cool down until it is "tacky " ;
then press the polished side of the tooth into close contact with
the glass and clip. When quite cold the grinding may proceed,
as in the first part of the operation, till you get the required thin-
ness, when that side may also be polished. The hard balsam
round the section supports and protects the edges, so that they
will not be fractured and made jagged and untidy. B,y not
putting the tooth on to the glass plate until the balsam is some-
what cooled, you prevent the polished surface from being covered
with fine cracks, which might remind you of a dinner plate which
a careless cook has over-heated till the glaze is cracked in all
directions ; it also prevents the balsam from running into the
tubular structure of the dentine.

As the process I adopt for mounting the section is appHcable
to all sections of hard tissues, I shall reserve my remarks upon it
till I have mentioned another plan of grinding down the rough
slices, which I can recommend from long experience on account
of its readiness, cleanliness, and the perfect parallelism of the
sections produced by it. Having a slice of dental or other hard
tissue of moderate thickness, place it between two plates of ground
glass, or between a plate of glass and a flat stone, such as an
Arkansas or Lake Washita stone, with water and a pinch of levi-
gated pumice powder, and by a rotary motion of the upper glass
gradually rub the section down till it is thin enough for examina-
tion with even the highest powers of the microscope. But
towards the end of the process be careful to watch it, for as the
glass and stone, or the two glasses, get closer together, and the
section thinner, one turn more of the upper glass will sometimes
result in the total disappearance of an hour's work, and you will
be eligible to take rank amongst beings of a very high order if an
explosion of your private opinion does not occur. Having ground
your section sufficiently thin by either of the before-mentioned
plans, it remains to be mounted in a suitable medium for
examination.

ON THE PREPARATION OF TOOTH SECTIONS. 201

Of all the media recommended, none fulfil the requirements
in so satisfactory a manner as Canada balsam if certain precautions
are observed, of which I shall speak presently. Canada balsam
is not, strictly speaking, soluble in alcohol, but is converted by it
into a white pulverulent condition. Therefore the plate, having
the thin section attached to it, may be placed in alcohol, and,
after a few hours' soaking, the thin section is easily detached with-
out fracture, but will be found coated with this altered Canada
balsam, every particle of which must be removed with a clean
camel-hair brush kept constantly wetted with spirit. Unless this
is done, the section will look messy and muddled when it is
mounted permanently. Having got it quite clean, it may be
placed in clean absolute alcohol till you want to mount it. It
might be considered that all this camel-hair-pencil work could
have been dispensed with by placing the section into some com-
plete solvent of the balsam, such as chloroform, benzole, or
turpentine ; but it must be remembered that, by so doing, we
should bring about the very thing we have been trying to prevent.
We want to mount our section without the highly refractive balsam
running into the minute structure and rendering it invisible ; and
that is the reason I recommend the treatment by alcohol.

There are two good methods of mounting bone and teeth in
Canada balsam, which, while securing the advantage we are
desirous of attaining, also preserve, in the highest degree, the
visibility of their histological details. That which I practice is
the simpler. Take your section out of the absolute alcohol and
let it partially dry, carefully protecting it from dust or other con-
tamination. When nearly dry, give it a good soaking in filtered
distilled water, that the tubular structure, or any minute spaces
like lacuna or canaliculi, may become filled with water; afterwards
dry its surfaces by wiping them with a clean warm finger, so that
all moisture is taken from them, when the section may be mounted
in rather firm balsam, with very little fear of the structure being
swallowed up in translucency. The reason blotting paper is not
used for preliminary drying is, that the fibres from it adhere to
your section and disfigure its appearance.

The second method of mounting is to plunge the section for
a moment into alcoholic solution of white shellac, and, quickly

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. p

202 ON THE PREPARATION OF TOOTH SECTIONS.

withdrawing it, the alcohol evaporates, leaving the porous structure
completely occluded and protected from the balsam, however
liquid it might be. I think that both these methods are produc-
tive of such satisfactory results that I can commend them to your
careful attention if you should at any time wish to preserve speci-
mens of dental histology.

The methods of preparing sections of teeth by decalcification,
though not new, have come in vogue of late. Many specimens
are better prepared by softening the hard parts, and cutting, after
suitable preparation, in a microtome. There is no doubt that
decalcifying processes are most useful in many instances. Chromic
Acid has for years been used for this latter purpose. It is claimed
for it that it hardens the soft parts while it softens the hard, both
changes taking place simultaneously. It is useful for fully-
developed human teeth, also for developing jaws of mammals in
which a fair amount of dentine, enamel, and bone, have been
already formed. The following is, though seemingly rather com-
plicated, wasteful, and troublesome, a very successful method : —

I. — A tooth is placed in a solution of Chromic Acid (crystals),
lo grains, to Water, 8 ounces. It should here remain for two days,
at the end of which a fresh solution must be used.

2. — After two days immerse it in a solution of Chromic Acid,
2o grains, to Water, 8 ounces, for four days.

■ 3. — Then in Chromic Acid, 2 ounces ; Water, 4 ounces ;
Hydrochloric Acid (2% solution), 4 ounces. The latter should be
added a few minutes after the Chromic Acid solution is made.

4. — Remove the tooth to fresh solutions, made up according
to the last formula, every fourth day until it is sufficiently soft (this
takes from eleven to twelve days). By using the Chromic Acid
as mentioned, the advantages derived from the employment of
fresh re-agents are assured.

5. — Immerse the tooth for half-an-hour in a large quantity of
alkaline solution, and wash under the tap for twenty-four hours.

The tissue is then ready for gum solution and cutting with the
microtome. Embedding in paraffin may of course be substituted
for the gum. Picric acid, in a saturated solution, is often employed
for the purpose of decalcifying. But for a ready solution that is
generally to hand, and the method I myself employ, there is

ON THE PREPARATION OF TOOTH SECTIONS. 203

nothing so effectual as a saturated solution of common alum, with
about half a drachm of Hydrochloric acid added to each ounce
of solution. Steeping the tooth (or teeth) in this for about three
weeks leaves the tooth with a consistency of cork. If it is now
soaked in glycerine for a few days it may be embedded and cut
into thin sections by any of the usual microtomes. I prefer this
to either Picric or Chromic acid, because it does not stain the
hands, and I believe does not produce so much granularity as
the other processes do.

Proceeding to the staining stage, Logwood is first on the list,
and can be prepared so as to be certain of working perfectly. The
way to prepare the extract is to dissolve it up in alcohol, add a few
drops of this to a saturated solution of potash alum, and, when
mixed, add a few crystals of phenol. This will give a brownish,
purple stain. Another very useful stain is Borax and Carmine ;
it will penetrate deeply into the tissue. The preparation consists
of J a drachm of Carmine and 2 drachms Borax, dissolved in
' distilled water. Aniline dyes form most useful stains with these •
all sorts of shades can be brought out. Another useful stain is
Osmic Acid. The real use of Osmic Acid is to bring out any fat.

In staining with Chloride of Gold, it really does not matter
whether the section be fresh or not, although many text books say
it is useless to attempt to stain tissues which have been deprived
of life more than an hour. The method described by Dr. Bodecker
has given the best results. He immerses the section, whether
cut from a decalcified tooth or ground down from a hard one, in
a solution of Carbonate of Soda for an hour. It is then placed
in a solution of Chloride of Gold, which must be neutral, and
left in the dark for another hour ; then put in the Carbonate of
Soda for a few moments, and transferred to a i per cent, solution
of Formic Acid, and kept warm over a bath for about an hour and
a half Finally, the section should be mounted in Glycerine Jelly
— not in Canada balsam. Sections which have been decalcified
by Chromic Acid take longer to stain than those that are fresh,
but the whole process only occupies from three to four hours,
instead of at least twenty-four hours as in the old method, and the
result will be found far more satisfactory. The usual needles, or
any sjeel instrument, must not be used for manipulating the sec-

204 SOME REMARKS ON CLARIFICATION, ETC.

tions ; some non-metallic substance, such as a quill tooth-pick,
should be used instead.

Having stained the specimen, the next step is to wash it, dehy-
drate, and clear it. Clearing means removing all those substances
which are of a lower specific gravity than the medium the speci-
men is to be mounted in. The clearing agents are : oil of cloves,
oil of cedar, oil of bergamot, and oil of sandal wood. Oil of
cloves is by far the most commonly used.

Some IRemarfea on Clarification, anb aleo
on a IRew Clarifier for flDicro6cop(cal

purpoeee/'

By Edwin A. Schultze.

(Read October igth, i8g4.)

ONE of the most important points to be observed in micro-
scopical research is the requisite clarification of the object
under examination. As simple, however, as this appears, the
views of the different authorities who have investigated the subject
do not appear to coincide. In studying plant sections, clarification,
according to Dippel, is resorted to to produce the necessary
transparency of the object, which on account of its contents does
not permit of a thorough investigation of the inner structure. The
usual clarifiers mentioned by Dippel are: Liquor potassse (in some
cases to be used with acetic acid and ammonia) ; potassic alcohol,
carbolic acid (when necessary to be used after treatment with
alcohol or mixed with turpentine); and finally chloral hydrate
(8 parts dissolved in 5 of water). Zimmermann, in his work
Botanische Mikrotechnik^ discriminates between the action of
the above named chemical clarifiers and the clarification by means
of more or less refractive mounting media, especially essential
oils, balsams, and resins. Of these latter he mentions Canada
balsam, dammar and Venetian turpentine. Tschirch, in his
" Pflanzen anatomic," speaks of employing only liquor potassse and

* Translation from the German of Dr. Wilhelm Lenz, Zeitschr. f. wiss.
Mikr. xi. 16 (1894), for the Journal of the New York Microscopical Society.

SOME REMARKS ON CLARIFICATION, ETC. 205

potassium chloride, with acetic acid for clarifying plant sections.

Moeller, to conclude, very correctly places water at the head
of his list of clarifying reagents ; then follow glycerine, alkaline
solutions, Javelle water, and finally chloral hydrate. There
appears to be a difference of opinion among the authorities on this
last mentioned clarifier, which Schimper frequently and highly
recommends. Behrens, in his extensive catalogue of clarifiers,
calls attention to chloral hydrate " as being only useful for animal
preparations" without naming his authority. Moeller mentions
chloral hydrate (5 parts in 2 of water) as having been recommended
by A. Meyer, and refers to a publication of this last named
authority m the '' Archiv der Pharmacie," but in which chloral
hydrate does not appear. Moeller says, furthermore, that chloral
hydrate is preferable to diluted Uquids, inasmuch as it leaves the
fecula unchanged.

Such is, however, not the case, for it is easy to demonstrate
that chloral hydrate causes every kind of starch to swell and change
into a pasty substance after about twenty-four hours' time. The
formation of this transparent paste does not in any manner inter-
fere with the admirable clarifying properties of chloral hydrate.

I have used chloral hydrate (8 parts dissolved in 5 of water) to
a great extent myself as a clarifier for plant sections, and have
also recommended its use to those students interested in micro-
scopy at the Fresenius College in this city, and believe I have
thoroughly investigated its advantages and disadvantages while
comparing it with other clarifiers. A short communication may,
therefore, be acceptable on this as well as on a similar clarifier
lately discovered by me, and which, I think, is somewhat superior
to chloral hydrate.

As already stated, Dippel has explained in a masterly manner
the reason for clarifying plant sections. The means for obtaining
this result are, i, the removal of troublesome substances, and 2, the
saturation of the object under examination with a body, the
refractive power of which is so nearly equal to that of the cell
walls, that the light may penetrate as much as possible ; but still
sufSciently different to admit of the cell walls appearing sharply
outlined under the microscope. The division of clarifiers into
chemical and physical by Zimmermann, seems to have originated

206 SOME REMARKS ON CLARIFICATION, ETC.

in the above, yet I cannot agree with him for the reason that most
of the clarifying solutions act chemically as well as physically, in
consequence of which they must be carefully examined and used
accordingly. This is especially the case with chloral hydrate. Its
excellent double action, chemical and physical, and consequently
the ease with which it may be used, has rendered it a very desirable
clarifier.

It is remarkable that as yet so little is known of the physical
properties and refractive power of the chloral hydrate solution.
According to my researches a solution of 8 parts c. p. crystallised
chloral hydrate in 5 parts of water has a specific gravity of i'3677
at 15*^ C. The refraction of sodium light is 1*4272, and the
divergence 0*0078. I have not been able to discover the refraction
of pure cellulose.

If we consider, however, that pure cellulose is clarified almost
to invisibility in Canada balsam, while remaining clearly percep-
tible in glycerine of less and styrax of greater refractive power, we
may conclude that the refraction of cellulose is about that of
Canada balsam. The mean refraction of the latter is said by
Behrens to be i'535.

There are a few drawbacks which must be mentioned in using
chloral hydrate as a clarifier. While the action of the alkaline
solutions may be nullified with acetic acid, and any turbidity
removed with ammonia, this is not the case wath chloral hydrate.
Fecula and almost the entire contents of the cells are more or less
dissolved by chloral hydrate and rendered transparent. In treating
these clarified objects with water or glycerine they become turbid.

These defects are far less perceptible in a solution that I have
been using for the past six months, and which is composed of
equal parts of sodium salicylate and water. This solution has a
specific gravity of i'23i5 at a temperature of 17^ C. Refractive
power 1*4497 and divergence 0*01318 at 15*4° C. According to
my former observations the refractive power of the chloral hydrate
solution would equal that of a 67 per cent, solution of glycerine.
The salicylate solution, as I shall call my new liquid, shows a
refraction equal to that of a solution of 82 per cent, of anhydrous
glycerine. The penetrating power of my solution is greater than
that of chloral hydrate on account of its low specific gravity. Its

SOME REMARKS ON CLARIFICATION, ETC. 207

refractive power is superior to that of chloral hydrate, without,
however, approaching too closely that of cellulose. It is, therefore,
for both reasons, more serviceable as a clarifier than chloral
hydrate.

As far as its chemical clarification is concerned the action in
swelling the fecula is very prompt. No starch grains were percep-
tible in sections of ginger after they had laid in the solution about
two hours. The colouring of the cell walls is also less changed by
salicylate than chloral hydrate.

The latter also gradually causes the cell walls to swell, and, in
the case of soft structures, they are sometimes rendered partially
imperceptible.

In using salicylate I have not discovered this defect; it appears,
on the contrary, to have a hardening effect on soft tissues.

If, as an instance, several thick sections of ginger-root, after
having lain about twenty-four hours in saHcylate, and the super-
fluous liquid carefully removed with filter paper, be mounted in
glycerine and examined, the cell walls will be found to be but
little swollen, and their colour, especially that of the cork cells,
well preserved.

All the thin strata appear sharply outlined.

In balsam mounts the details become even more clear and
beautiful.

In objects which have been treated with chloral hydrate the
cell walls will be found more swollen, their colour fainter, their
outlines less clearly defined, and the structural details, although in
general discernible, somewhat obliterated.

Chloral hydrate is, consequently, only serviceable in examining
thick objects, and when these are to be decoloured as much as
possible. Dyes containing tannin are more influenced by chloral
hydrate than by salicylate. The best way to eliminate them is by
means of alkaline solutions and afterwards, when necessary, with
Javelle water.

Fecula, when swollen in chloral hydrate, forms a transparent
jelly, which becomes considerably turbid when a small quantity of
water or glycerine is added ; a turbidity which increases and forms
a thick deposit if this supply is increased.

The jelly produced by fecula swollen in salicylate is much more

208 SOME REMARKS ON CLARIFICATION, ETC.

transparent, does not become cloudy through the addition of
concentrated glycerine, and remains, when treated with water,
moderately translucent. The swelled fecula reacts with iodine in
both cases, but producing two different colours, viz. : the chloral
hydrateared, and the salicylate a pure blue. Salicylate with iodine
would, for this reason, be valuable for discovering traces of starch.
Salicylate in general has the advantage of containing a neutral,
non-corrosive, non-poisonous, and non-hygroscopic salt, its principal
chemical virtue being an extraordinary power for swelling starches.
The chief feature, however, which renders salicylate so admirably
useful in microscopy, is its miscibility with phenols, notably oil of
cloves. If one drop of oil of cloves be mixed with lo of salicylate
an opalescent liquid will be obtained, which becomes clear by
adding a second drop of oil of cloves. If this process of adding
oil of cloves be continued, about the 20th drop will produce a
cloudy solution, which may be clarified by a single drop of salicylate.
A liquid may thus be obtained with a refractive index of i'5, which
is about that of cellulose.

Weather-Charts. — Atmospheric pressure, and consequently
the height of the barometer, varies not only from place to place,
but also, in any one place, from day to day, and even from hour to
hour. All those movements of the air that we know as winds are
due to more or less local differences of atmospheric pressure ; varia-
tions in the force and direction of the wind are among the chief
factors in weather ; and so the barometer, by showing whether the
pressure is on the increase or on the decrease, whether rapidly or
slowly, enables us to foretell changes of weather. The actual height
of the mercury being of far less importance than the direction and
rate at which it is moving, the words "change," "fair," "set fair,"
etc., usually placed by the side of the instrument, are of little value.
The chief points in weather-charts are, therefore, the readings of the
barometer at various places at short intervals of time — usually daily.
Lines joining places which have at a given time the same baromet-
ric pressure are called isobars or isobaric lines. These are generally
drawn for every tenth of an inch, and the distance between two
successive lines gives us the gradient. By this we mean the slope
of the atmosphere, just as a railway engineer uses the term for the
slope of the ground. An engineer will speak of a gradient of 4 in
100, meaning a rise of 4 feet in 100 feet of distance ; in weather-
reports the units of distance is a degree of 60 geographical miles,
and the vertical scale is in hundredths of an inch of the barometer.
Hence a gradient of 4 means a rise of 4/iooths ( = i/25th) of an
inch in a degree. — CasseWs New Popular Educator for Dec.

[ 209 ]

Co*=opecat(on in plante/'

By Geo. Clayton, F.C.S., of the Northern Col. of Pharmacy.

THE matter I propose to speak about is symbiosis, also to
touch on parasitism, though more with the object of dis-
tinguishing between it and symbiosis, and also to give
illustrations of pure partnership between one plant and another
plant, and also between a plant and an animal. A pure parasite,
as most of you will know, is a plant or animal which, living on
another plant or animal called its " host," withdraws nutriment
from it, without in any way contributing to the support of its host.
In the plants yellow-rattle, cow-wheat, etc., we have good examples
of plants parasitic on other plants. Here I must mention that
parasites must not be confounded with epiphytes or saprophytes.
Epiphytes being plants like the orchid, which are attached to other
plants, but derive no nutriment from them, getting their nourish-
ment from the air by means of their pendulous roots. The
saprophytes being plants like the toad-stool, which live on dead or
decaying vegetable matters. A true parasite then lives on its
living host, having mechanical attachment with it and withdrawing
nutriment from it, but giving the host-plant nothing in return.
The common yellow rattle, whose yellow flowers are seen in
every pasture field, lives on the roots of the clover, and takes
its sustenance from it.

But in a great many cases it is most difficult to decide for
certain that the host-plant does not get some advantage from the
parasite which drains its juices. Should this be the case, however,
the latter would no longer be a parasite, and the relationship
between the two would be one of mutual assistance — a partnership
for the benefit of both. Until lately, for example, the mistletoe
was regarded as a true parasite; but some botanists now state that
this plant, the mistletoe, contributes food stuff (starch, cellulose,
etc., which it has manufactured in its leaves) to the oak, apple, or
poplar tree to which it is attached. These botanists point to the
enlargement, corpulence, or general robustness of the apple stem
in the particular place where the mistletoe is attached, and argue

* From the British and Colonial Druggist.

210 CO-OPERATION OF PLANTS.

that if the mistletoe were a true parasite the tissue of the apple
would be attenuated where the mistletoe was joined. At the
present time, we cannot state with certainty the relations between
the host tree and the mistletoe, but the tendency of research in
similar instances has been to prove reciprocity between plants
formerly regarded as parasite and host ; so that probably this, too,
may be eventually established as an instance of co-operation
in plants.

However, in a very great, many cases, it is distinctly proved
that there are plants living in union with each other, and which
may be said to be in partnership, or in true co-operation, each
plant handing over to its fellow material that the other specially
requires, and which alone it would have great difficulty in obtain-
ing. This is symbiosis, bringing me to the principal subject
of my paper.

Symbiosis in plants then may be defined as " the associated
existence of two or more plants for purposes of nutrition. Unlike
parasites, two symbiotic plants living in union each supplies its
partner with material which the partner requires." A give-and-take,
or reciprocity system, being the rule of their combined existence.

I propose to divide the illustrations of symbiosis or co-opera-
tion into three divisions :

I. — The symbiosis of green-leaved, flower-bearing plants with
fungi.

2. — Symbiosis of algae with fungi.

3. — Cases of animals and plants in symbiotic relationship.

The first division of my subject is the symbiosis of flowering
or phanerogamous plants with fungoid partners. The fungus, as
most of you will know, is a cryptogamic or flowerless plant, con-
taining no green colouring matter in its cells. The mushroom is,
of course, the best known example ; but by far the greater num-
ber of fungi, instead of possessing the solidity of the mushroom,
are composed of greyish-white, stringy threads, termed myceloid
filaments, and these are the kind I wish to refer to in particular.
The union of the two partners takes place underground, the roots
of the larger plant, the tree, being woven over by the thread-like
filaments of its partner —the fungus. The root that descends from
the germinating seed into the ground becomes entangled with the

CO-OPERATION OF PLANTS. 211

myceloid filaments of the fungus already existing in the soil ;
henceforward the connection continues until death. As the root
grows onward the myceloid fungus grows with it, accompanying it
like a shadow whatever its course. The ultimate ramifications of
roots of trees a hundred years old, and the young roots of year
old seedlings, are both covered by the myceloid mantle in the
same manner. Gardeners for years have experienced great diffi-
culty in rearing various specimens of rhododendron, winter green,
broom, heath. This difficulty is now traced to the fact that the
roots of the rhododendron, for example, is unable to find its sym-
biotic partner in some soils in which it is transplanted, or through
which the new roots are piercing their way ; the transplanted
rhododendron, therefore, perishes on account of its being unable
to assimilate the necessary materials from the soil. On the other
hand, the roots of the healthy, vigorous rhododendron are found
to be invested by the fungoid partner.

The partnership or symbiosis, therefore, in the instance just
mentioned is between the rhododendron and the fungus which is
attached to its roots. The larger tree providing the fungus with
starch and other organic materials elaborated in the green leaves
of the tree, whilst the smaller plant supplies the rhododendron
with moisture and mineral matters which the fungus absorbed
from the ground. The filaments of the fungus grow in sinuous
curves, forming a felt-like coat round the root. In colour the
filaments are mostly brown or grey, and through the tangle of
fungus filaments the root may often be discerned here and there,
whilst in some instances the fungus even penetrates some distance
into its partner. The fungoid plant is provided externally with
hyphae, or hair-like processes, which pierce the earth, taking up
nutriment, and handing it over to its larger partner.

A further proof that a symbiotic partner is indispensable to
certain plants, is found in the fact that when the attempt to rear
seedhngs of the beech and fir is made in a soil destitute of humus
(that is, fungus filaments), the seed, after germinating and growing
a short time, perishes ; but if soil or mould, recently dug from the
ground in a wood, and known to contain the living mycelium of
the fungus, be placed at the root of the seedling, it at once begins
to grow vigorously, owing to it having " connected on " with the

212 CO-OPERATION OF PLANTS.

smaller subterranean partner, which feeds it from the ground.
The number of plants having symbiotic relations of the kind
described is very large ; most of the Ericacece, including heathers,
rhododendron, and similar plants ; Coniferce, including firs of all
kinds ; Salicacec^^ including poplars, willows ; and all Cupuliferce,
like the oak, beech, etc.

It is of great interest to note that the chief species of flowering
plants which are symbiotic are gregarious in character, and, like
the oak, fir, and heather, form large forests or moors, and one is
filled with wonder at the magnitude of the immense colonies of
subterranean fungi which must exist, interlacing themselves at the
roots of such forests of trees.

It will also be plain why there is such a profusion of fungi of
all kinds in forests around the roots of certain large trees. We
cannot yet state precisely the exact species of fungi which contract
union with these plants, or whether there is a selective affinity
between flowering tree and fungus. But this much is known — the
flowering plant, rather than be at a loss for a fungoid partner, will
unite with other fungi than it is usually connected with.

Then again there are instances of certain trees living in sym-
biotic union with another plant, and at the same time beset by
animal and vegetable parasites.

For instance, the common black poplar has its roots in symbi-
otic union with a fungus for purposes of nutrition. Then other
parts of the roots of the poplar will have the parasite toothwort
feeding on them ; again, on the upper branches of the same tree
may be found the mistletoe, whose presence on the poplar tree is
due to the bird, the missel thrush, which, through eating the berries
of the mistletoe, disseminates the seeds. The mistletoe, in turn,
will have lichens attached to it.

In all, I suppose the poplar tree has nearly fifty plants or
animals living in symbiotic or parasitic association with it.

I now come to the second part of my paper, namely, the co-
operation or symbiosis of algae with fungi. Almost the first place,
if not the most interesting one, in symbiotic communities, ought
to be assigned to the lichens, to which, as will be well known, the
Iceland moss and the litmus plant belong. These organisms, the
lichens, which were once classed as separate plants, are now
acknowledged to be of a composite character.

CO-OPERATION OF PLANTS. 213

Each lichen, being comprised of, first, a fungus, made up of a
web of myceloid threads, with, second, an alga in its interior,
this combination of alga and fungus thus forming the one lichen
plant. I must state at this point, to make myself clear, that an
alga is a cryptogamic or flowerless plant, without any distinction
between stem and leaf, and containing green colouring matter.
The ordinary seaweeds are examples of algae, also the green slime
found in stagnant water ; but the algae which live in partnership
with fungi, forming lichens, are very minute plants, numbers of
them being unicellular, but all of them containing green colouring
matter inside their cells ; they mostly belonging to the natural
order Nostocince.

The myceloid threads of the fungus being most exterior fulfil
the function of gathering from the air moisture, and from the
ground or substratum mineral matters ; whilst its partner the alga,
owing to its having chlorophyl or green colouring matter, manu-
factures starch and other organic chemicals. Thus here again the
partners supply each other with matters necessary for the life of
both. Then as to the creation of a lichen. A simple experiment
will illustrate the facility by which a lichen may be created. If a
sheet of white blotting paper moistened with water be exposed for
several hours to the wind in the country, and then its surface care-
fully examined with a microscope, numerous particles like dust will
be found deposited on the paper ; these particles consisting of cell
groups of algae, pollen, grains, spores of mosses and fungi, etc.
All these bodies would, under natural circumstances, have been
deposited in the crevices of the bark of trees, on rocks, stones, etc.,
and we can easily see, if in these places the little algal cell groups
meet with their partner the fungus, the latter will embrace and en-
mesh them, and thus create a confederacy known as a lichen.
Thus we can easily understand how it is that the bark of trees,
rocks exposed to moisture, etc., become clothed with these lichens.

A most interesting proof of this union is afforded by the fact
that a celebrated botanist, M. Bornet, has actually synthesised a
lichen — that is, created one. Commencing with certain definite
algae, he sowed them, in company with certain definite fungi, in
a favourable place. The two separate plants amalgamated and
interwove their cells, with the result that a lichen was formed.

214 CO-OPERATION OF PLANTS.

It is necessary to add, however, that lichens as we find them,
growing on bark of trees, etc., do not in all cases owe their origi-
nal appearance on the locality where found to a fresh union of an
alga with a fungus, but there is another mode of distribution of
lichens. The distribution of numerous lichens is brought about
by the wafting with the wind of already completed social colonies
to places often situated a great distance from the locality where
the first union of alga and fungus was contracted, the process
being as follows : — In a matured lichen, several cells all bound
together^ called a soredium, detach themselves from the parent
plant, and are blown by the wind to a fresh spot, where, stranding,
they establish themselves, commence to grow, and eventually en-
large into a full-sized lichen.

Now, after reviewing the various cases of symbiosis mentioned
as occurring between two plants, and also in inquiring into the
habits of some animals, we find that we may take a step further
and say that many animals and plants have symbiotic relations. I
now arrive at the third division of my subject, namely : — Cases of
co-operation between certain animals or insects and plants. In
such a partnership as this the plant partner is materially assisted,
sometimes with food, protection from enemies, etc., by the animal,
and in return contributes food, shelter, etc., to the animal.

Although the two partners may not always live in union
(though, no doubt, they do sometimes), yet the reciprocity between
them is most perfect, establishing symbiosis conclusively. As the
first instance of this kind of co-operation, the well-known action
of insects in distributing pollen from flower to flower may be cited,
the insect getting as its own share in the transaction the honey
from the nectaries of the flowers it visits, while the flowers gain
by being cross-fertilised. Then again, many sea anemones have
seaweeds growing on them, the anemone receiving material from
the weed, and in return contributing matter for the support of the
weed. But probably the most interesting example of partnership
existing between the animal and plant is that of the fig tree and
the wasp. It may not be generally known that in the fig growing
countries there are two varieties of fig cultivated. One variety
which bears true or edible figs, called the Ficus variety, and

CO-OPERATION OF PLANTS. 215

another variety which is productive of barren or worthless figs,
called the Caprificus variety.

The inflorescence of the fig, most of you will know, is termed
a hypanthodium, being pear-shaped externally, but hollow in its
interior, where there are numerous flowers supported on a con-
cave receptacle.

The flowers at the base of the inflorescence are usually pistil-
late, or female flowers, those at the top male or staminate. Now
the female flowers of the Caprificus or barren variety have short
styles, and they mature long before the male flowers, which are at
the summit of the inflorescence. The female flowers in the Ficus
or edible fig, have very long styles, each bent like a hook. Now
the insect, really a species of wasp, enters the inflorescence of the
Caprificus, or barren fig, proceeds to the female flowers, sinks its
ovi-depositor down to the short style, and deposits the egg inside
the ovary. The iarva from the egg increases in size, and fills
the whole of the ovary, which thus becomes abortive, producing
what is termed a gall-flower, so that in the Caprificus, or barren
fig, all the ovaries of the female flowers have been converted into
gall-flowers, hence its barrenness. The insects inside the galls,
when hatched, eat their way out from the gall, creep to the top of
the inflorescence, and on emerging have to forcibly brush through
the male flowers, which are now ripe and discharging their pollen ;
thus, the wasp on emerging is covered with pollen. These insects,
seeking a place to deposit their ova, arrive at the inflorescence of
the fertile fig, into which they descend and proceed to the pistil-
late flowers. These pistillate flowers have different styles to those
of the barren fig, and the wasp is unable, in nearly all cases, to
deposit the egg in these ovaries, on account of the great length
of the style and its hooked nature ; therefore the wasp, in its
fruitless endeavours to enter, passes from flower to flower, dabbing
the pollen brought from the other fig on the stigmas of these
flowers, so causing the cross-fertilisation which is so imperative
for the formation of good individuals. The labour of the insect is
rewarded probably, after visiting some hundreds of flowers, by
finding a flower suitable to lay its eggs in. The plant gains by
being cross-fertilized ; the insect gains in return shelter for its
young. The two therefore co-operate. In order that this action

216 CO-OPERATION OF PLANTS.

may be facilitated, the fig growers take branches from the Capri-
ficus variety and hang them on the trees of the true fig, the
operation being termed " Caprification."

Then the case of the Yucca lily and Yucca moth is another
interesting instance of symbiosis. The Yucca lily is a handsome
plant, growing in California, and bearing pendulous flowers in
shape like the tulip. These flowers are visited by the female moth,
known as the Yucca moth. This insect seems to make a special
object of collecting the pollen from the stamens, rolling this pollen
into round balls, and carrying it to another flower. Arriving there
the moth, by means of a long tube, bores a hole right through the
wall of the ovary, and lays its eggs inside the ovary near the young
ovules, then creeping up the style the moth places the pollen
which it brought from the other flower on the stigma, and even
forces this pollen down the style as far as it can. The ovules are,
of course, fertilised by this pollen, which, coming from another
flower, causes the ovules to ripen into sound succulent seeds.
The eggs meanwhile, becoming hatched, form young moths inside
the ovary, and these young insects eat up as food many of the
succulent seeds before they escape out to the light. Therefore,
there is no doubt that, in return for the depositing of this pollen
and consequent fertilising of its ovules, the Yucca plant repays the
moth by sacrificing some of its seeds as food to the young moths.
Yuccas grown where there are no moths produce no seeds, through
no fertilisation taking place.

I might enumerate many other examples of decided symbiosis
between plants and animals, but will be content with the four or
five mentioned, as I think these will suffice to prove that between
certain animals and plants we have a most interesting system of
reciprocity existing. It will, however, be useful to state that the
formation of galls on the oak, willow, etc., caused by certain insects
laying their eggs, cannot be regarded as furnishing an instance of
symbiosis, the advantage, as far as can be seen at present, being
all on the side of the animal, so these gall excrescences must
therefore be regarded as parasitic structures.

[ 217 ]

Hnotbcr Conetitucnt of tbe Htmoepberc*

IN announcing the recognition of Argon, not quite two months
ago, as a constituent of the atmosphere, we said : " The new
element will be a fresh instrument of research." The predic-
tion has already been realised. At the annual meeting of the
Chemical Society, held Wednesday, March 27, the Faraday medal
was presented to Lord Rayleigh for his discovery of Argon, and
no sooner was this done and the presentation suitably acknow-
ledged, than Professor Ramsay, the fellow-worker with Lord Ray-
leigh in that discovery, surprised the chemists present with the
announcement that he had found another new element associated
with Argon, and he proceeded briefly to explain the nature of his
remarkable find, which has in it features as romantic as the detec-
tion of Argon itself, and must have highly important consequences
to the future of chemical and physical enquiry.

We say romantic advisedly. It is surely a wonder-awakening
circumstance when the first evidence of something we possess on
earth comes to us from the sun, and then that the chemist should
find this substance in a very rare earth, and at length, by the use
of the most refined methods of science, arrive at the fact that this
material is probably one of those that make up the very air we
breathe. Such was, in short, the meaning of Professor Ramsay's
communication to the Chemical Society. A ray of light comes
from the sun and is passed through a small prism of glass — the
spectroscope. In the image of that ray, broken into its several
colours, there are certain lines which show the existence in the sun
of iron, of sodium, of hydrogen, and various other elements, most
of which exist on this planet and behave in the same way towards
light. But there are some lines that seem to betoken the presence
in the sun of a substance we know nothing of. Nature is constant.
The lines are always there, and the physicist does not hesitate to
give a name to the hypothetical element — of which there was not
a vestige of evidence to be had elsewhere. On the faith of rays
of light, decomposed by a suitably mounted glass prism, he

* From Daily Telegraph, March 28, 1895.

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. o

218 ANOTHER CONSTITUENT

asserted that there existed in the sun a substance which he called
on that account Helium. This element Professor Ramsay now
believes he has proved to be not only one of our terrestrial ele-
ments, but allied with Argon, the new component of the atmo-
sphere.

There were two or three suspicious characteristics about Argon.
In the first place, it was most unsocial — it would combine with no
other substance ; and, secondly, it did not fit into Mendeleeff's
great law, which connects the weights of the atoms and molecules
of matter with their qualities. " So much the worse for the law,"
said some ; but the older chemists were hardly willing to see the
breakdown of one of the grandest generalisations of modern
times. Professor Ramsay's discovery probably gets rid of both
these suspicions attaching to the new gas. In order to find out
whether there was not something in the world with which Argon
would keep company, he was examining an extremely rare earth
found in Norway, and known as cleveite, after its discoverer, the
Swedish chemist, Cleve. When this mineral is treated with weak
sulphuric acid, it gives off a gas which hitherto has always been
regarded as nitrogen. The Professor found, by very close exami-
nation, that it was not nitrogen at all, but Argon ; and, moreover,
there was associated with it another gas, which also upon rigorous
scrutiny he found to be, to use his own words, " a gas which had
not yet been separated." He submitted it to Professor Crookes,
who is eminent as a spectroscopist as well as a chemist, and the
result is to show almost with certainty that the gas thus found is
none other than Helium. Just as the nitrogen of the atmosphere
was shown by Lord Rayleigh and Professor Ramsay to hide within
it another gas — Argon ; so Argon is now proved to contain ano-
ther element until now thought to exist only in the sun. The
spectroscope told us that 91,250,000 miles away, on the bright
incandescent solar surface, where everything known on earth would
be melted into vapour by fervent heat, there was present a gas
never met with here ; aud now, by dint of laborious research, the
chemist finds it, in an extremely rare earth it is true, but probably
a constituent of the atmosphere that supports all terrestrial life.

The discovery was made and confirmed by Mr. Crookes's
spectroscopic examination quite recently. Terrestrial Helium has

OF THE ATMOSPHERE. 219

yet to be fully examined ; its weight, specific heat, chemical affini-
ties, and other properties, to be ascertained. Professor Ramsay
believes that when these qualities are known they may explain the
anomalous position of Argon in its relation to other bodies. The
question arose when that strange gas was detected — Is it an ele-
ment, is it one body or a combination, or is there some other mixed
with it, or is it nitrogen in what is called an allotropic condition ?
The last suggestion may be put aside. It is now pretty clear that
" atmospheric Argon did contain some other gas not heretofore
separated," and that this gas is Helium. It becomes so much the
more probable that Argon will be found to fit into the system of
elementary bodies according to Mendeleeff's law.

What, it may be asked, does it matter whether the list of ele-
ments extend to sixty-five, sixty-seven, or any other number ? To
chemical theory it is all-important, and chemistry is the most fruit-
ful of all sciences in its contributions to human well-being. These
elements are the pillars of the material universe. It is a favourite
peroration with the popular orator to refer to the fall of empires
and the crash of worlds. If the latter cataclysm should ever
happen, the one thing that would stand the shock would be the
ultimate atom. If, for example, the earth could suddenly be
stopped in its orbit and should fall headlong into the sun, as it
would, every drop of its water would be resolved into oxygen and
hydrogen, and every mineral and metal it holds would be vaporised;
but the ultimate atoms of nitrogen, carbon, oxygen, iron, and the
like would be unchanged and unchangeable ; ready to enter into
fresh combinations that would endure through new eons of exist-
ence. These atoms that belong to the infinitely little, of which
millions of millions can find room and verge enough to keep up a
ceaseless dance within a single cubic inch, and the force of whose
impact we call heat, are profoundly interesting entities. Clerk-
Maxwell based upon them an irresistible argument for a Creator.
For these, he said, can be derived by no system of evolution, and
each one of them changeless in weight, and size, and properties,
bears the impress of " a manufactured article."

[ 220 ]

tlbe flora of the Mabasb Dalle^.*

THE composition of the remarkable forests which, in spite of
the terrible inroads that have been made in them during
the last twenty-five years, still cover considerable portions
of the region in southern Illinois and Indiana watered by the
Wabash River and its tributaries, was first made known to the
scientific world by a paper published in 1882 in the fifth volume
of the Proceedings of the United States National Museum, by Dr.
Robert Ridgway, the ornithologist of the Smithsonian Institution.

In a second paper on the Wabash Silva, recently published in
the seventeenth volume of the Proceedings of the Natio?ial Museum,
Professor Ridgway shows that the number of indigenous arbores-
cent species in the Wabash valley south of the mouth of White
River is one hundred and seven, or more than a quarter of all the
arborescent species in N. America north of Mexico, and even this
number can be slightly increased, as one or two species of Cratce-
gusy overlooked by Professor Ridgway, grow near Mount Carmel.

Some idea of the surprising richness of the forest-flora in this
region can be obtained by an examination of Dr. Ridgway's
list of trees growing on restricted areas. On a tract of seventy-
five acres he found fifty-four species of trees, and another of
twenty-two acres contained forty-three species. On a tract of
forty acres one mile south-east of Olney, in Richland County,
lUinois, what the author modestly calls an imperfect survey of the
woods shows thirty-six species. The nearest approach to such a
concentration of tree species in a restricted area is in central Yezo,
where Professor Sargent found sixty-two species and varieties of
trees growing in the immediate neighbourhood of Sapporo at
practically one level above the sea.

The height attained by these Wabash valley trees is as remark-
able as the number of species in the forest. Individuals of forty-
two species reach a height of one hundred feet, and those of
twenty-one species grow to the height of one hundred and thirty
feet. Individuals of one hundred and fifty feet high of thirteen of
these species have been measured. A specimen of Quercus

* From Garden and Forest^ March 13, 1895.

FLORA OF THE WABASH VALLEY. 221

Texafia, called Quercus coccinea by Dr. Ridgway, the tallest of the
Wabash oaks, and perhaps the tallest oak in North America,
measured one hundred and eighty feet, and a tulip-tree one hun-
dred and ninety feet ; a Pecan, the tallest hickory, one hundred
and seventy-five feet ; a Cottonwood {Fopiilus monolifera), one
hundred and seventy feet; a Bur Oak {Quercus macrocarpa), one
hundred and sixty-five feet ; while, in addition to the trees already
mentioned, a Liquidambar and a i31ack Oak attained a height of
one hundred and sixty feet. The size of the trunks of some of
these trees, measured at three feet above the surface of the ground,
is hardly less remarkable than their height. A Sycamore {Platanus
occidentalis) girted thirty-three and a third feet ; a Tulip-tree twenty-
five feet ; a White Oak twenty-two feet ; a Black Walnut twenty-
two feet ; a Black Oak twenty feet ; and a Texas Oak twenty feet.
In comparison with such trees, the inhabitants of eastern forests,
where trees one hundred feet tall are extremely rare, appear like
pigmies, and persons familiar only with forests of the Atlantic sea-
board can form no idea of the magnificence of these trees, the last
remaining vestiges of the forests which covered the valley of the
Mississippi when the white man first floated down its placid waters.

This region is the home of some of our most beautiful and
valuable trees. On the bottom-lands of the rivers the Pecan and
the great western Hickory {Hicoria laci?iiosd) grow with all the
Swamp White Oaks, the Pin Oak, the Texas Oak, and that remark-
able form of the Spanish Oak, which, usually an upland tree, sends
up on these bottom-lands a tall, beautiful shaft covered with pale
bark, which might readily be mistaken for the trunk of one of the
White Oaks.

No other American forest-scene is more beautiful, and certainly
no other forest of deciduous trees, for it must be remembered that
in all this great collection of trees there is not a single species with
evergreen leaves is more interesting. No picture can give an idea
of the stateliness and grandeur of these noble trees, or of the
luxury of the annual and perennial plants that cover the forest,
floor with almost impenetrable thickets.

[ 222 ]

^be Iflee of paraeitic & ipre&aceoue Sneecte.*

By Clarence B. Weed.

THERE has recently been much discussion concerning the
ing utilisation of parasites and predaceous insects in destroy
injurious species. A knowledge of the conditions under
which such insects act would render it evident that we cannot hope
to exterminate any species of noxious insect by means of its para-
sites alone; and many too sanguine expectations have been aroused-
But, on the whole, parasitic and predaceous insects are of immense
service to man. Without them many plant-feeding species would
multiply to such an extent that the production of certain crops
would require vastly more effort than it does now. To say, as has
been said, that parasitic and predaceous insects have no economic
value, is to put the case too strongly. Take, for example, two crop
pests of the first class — the army worm and the hessian fly. The
history of a century shows that these insects fluctuate in numbers ;
that there are periods of immunity from their attacks, followed by
seasons when they are overwhelmingly abundant. It is universally
acknowledged that in the case of the hessian fly, this periodicity is
due almost entirely to the attacks of parasites, and in the case of
the army worm to the attacks of parasites, predaceous enemies, and
infectious diseases. Remove these checks and what would be the
result? The pests would keep up to the limits of their food supply
and would necessitate the abandonment of the culture of the crops
on which they feed. Take another case : — Professor J. B. Smith
has argued that " under ordinary conditions neither parasites nor
predaceous insects advantage the farmer in the least," and to prove
it he cites this instance : — " Fifty per cent, of the cutworms found
in a field early in the season may prove to be infected with para-
sites, and none of the specimens so infested will ever change to
moths that will reproduce their kind. Half of the entire brood has
been practically destroyed, and sometimes even a much larger pro-
portion; but — and the ' but ' deserves to be spelled with capitals —
these cutworms will not be destroyed until they have reached their
full growth, and have done all the damage to the farmer that they
could have done had they not been parasitised at all. In other

* American Naturalist.

MICROSCOPICAL TECHNIQUE. 223

words, the fact that fifty per cent, of the cutworms in his field are
infested by parasites does not help the farmer in the least."

But obviously it does help the farmer very greatly the next
season, for it reduces by half the number of cutworms he will have
to contend with. As a matter of fact, cutworms fluctuate in
numbers in a way quite similar to the army worm, and the fluctua-
tions are largely due to parasitic enemies. I have seen regions
where cutworms were so abundant that grain-fields were literally
cut off by them as by a mowing machine, and the following season
the worms were so scarce as to do practically no damage.

But Professor Smith is right in saying that as a general rule
there is too great a tendency to rely on natural enemies to subdue
insect attack. It is nearly always safer to adopt effective measures
in keeping pests in check than to trust to the chance of their
natural enemies subduing them.

flD(cro6coptcal ^ecbnicjue.

Compiled by W.H.B.

Koch's Solution of Methylene Blue.

Saturated alcoholic solution of Methylene Blue i drachm.
Solution of Caustic Potash, lo per cent. ... 12 minims.

Distilled Water ... ... ... 200 drachms.

The stain is very active in a feebly alkaline state.

Artificial Reproduction of Anhydrite from Evaporation of
Salt Solutions. — Brauns * has produced anhydrite in microscopic
crystals by bringing upon an object-glass a large drop of a satu-
rated solution of sodium or potassium chloride, or a mixture of
the two salts, and placing to one side of this a drop of calcium
chloride solution, and on the other side a drop of Epsom salt
solution. The three drops are joined to one another by narrow
paths and evaporated. During the diffusion of the liquids which
takes place, calcium sulphate is formed and appears in crystals of
both gypsum and anhydrite along with the crystals of the chlorides.
When a little water is added to a group of anhydrite crystals, they
are dissolved to re-crystallise as gypsum. By properly regulating

* Neues /ahrbuch f. Min., etc., 1894, II., pp. 256 — 264, in American
Naturalist^ Feb., 1894.

224 MICROSCOPICAL TECHNIQUE.

the amount of water added, Knaikl of gypsum may be formed
with a corroded core of anhydrite. Although anhydrite has been
frequently produced artificially, none of the methods heretofore
used have simulated its production in nature from the evaporation
of sea-water.

An Excellent Etching Fluid for Glass has recently been pub-
lished in the Central Zeitung fur Optiker unci Mechaniker^ xii., p. 57.
It consists of. two solutions which are to be kept in separate vials,
and prepared according to the following directions : —
No. I. — Dissolve sodium fluorite ... 36 grams.

in distilled water .,. ... 500 cubic centimeters.

and add potassium sulphate ... 7 grams.
No. 2. — Dissolve zinc chloride ... 14 grams.

in distilled water ... ... 500 cubic centimeters.

and add cone, hydrochloric acid 65 grams.
These solutions can be kept in ordinary glass vessels, hence no
gutta percha bottles are necessary. When wanted for use equal
volumes are mixed in a suitable vessel, best in a hollow paraffin
cube, which is easily made by cutting a hole in a piece of paraffin
with a knife. A small quantity of Indian ink is recommended as
an addition in order to enable the writer to see what he has
written. This fluid is said to be superior to the more difficult
preparations, and it is said that the finest hair lines have been
etched on glass with this medium. — Meyer's Druggist.

Bacteriological Examination of Blood and Tissues.— Inghilleri^
gives a new rapid double staining method for bacteriological
examination of the blood and other tissues, including the study of
phagocytosis and parasites of malaria, which he claims to excel,
not only in quickness but in precision. A cover glass preparation
(by the usual methods), or a section prepared from the tissues, is
placed in chloroform for thirty minutes, and afterwards stained in
the following fluid : — i per cent, solution of eosin in 70 per cent,
alcohol, 40 parts ; saturated aqueous solution of methylene blue,
60 parts, the specimen being gently warmed in this fluid for two or

* Central b. fur. Bakteriol.^ May, 1894, in Btit. Med. fourn., June 21,
1894, Epit., p. 13.

MICROSCOPICAL TECHNIQUE. 225

three minutes ; after which they are ready for immediate observa-
tion (for example, blood, etc.), or after dehydrating, clearing, and
mounting as usual.

Borofuchsin as a Stain for Tubercle Bacilli.^— Prof. Lubimoff
describes in the Meditsinkoe Obozrenie a new stain for tubercle
bacilli, which he calls Borofuchsin. It consists of

Fuchsin ... ... ... 7 J grains.

Boracic Acid ... ... 7^ grains.

Absolute Alcohol ... ... 4 drachms.

Distilled Water ... •••5 drachms.

When prepared in this way, it has a slightly acid reaction. It
is quite clear and not liable to be spoilt by being kept, and conse-
quently it is always ready for use. The sputum is dried on a
cover-glass, and stained by being heated in contact with the boro-
fuchsin for one or two minutes. The stain is then washed out by
treatment with dilute sulphuric acid. The specimen is then washed
with alcohol, and subsequently immersed for half a minute in a
saturated alcoholic solution of methylene blue. After being washed
in distilled water and dried, the examination of the specimen is
made in oil of cedar or in a solution of Canada balsam. In
exactly the same way sections of tuberculous organs may be stained
after hardening in spirit, only in such cases the steps of the opera-
tion must be somewhat more prolonged. The main difference
between this and other staining processes for Koch's bacilli is that
when borofuchsin is used the process of washing it out with sul-
phuric acid is an almost instantaneous one. All other bacilli are,
as when other stains are used, rendered colourless and invisible,
the tubercle baciUi alone being seen.

For mounting preparations cleared with chloral hydrate which
it is desired to retain in their transparent condition, Geoffrey
suggests (Journ, de Botanique^ vii., 55, 1893) a solution of 3 to 4
grms. of pure glycerine in 100 grms. of 10 per cent, chloral
hydrate. This can be used like glycerine, with the added conven-
ience that it hardens at the edge of the cover, so that the cover
can be cemented without tedious cleaning.

* Lancet,

226 NOTES.

Preparing Large and Thick Sections.— Dr. H. Scheneck
recommends {Bot. Cent, liv., April, 1893), a method of preparing
unusually large and thick sections for permanent preservation so
as to be useful for lecture demonstrations and for examination with
the magnifier. The sections are first thoroughly permeated by
glycerin by prolonged soaking; the superfluous glycerin is drained
off and the section dried with filter paper ; it is then placed in an
abundance of a thin solution of Canada balsam in xylol, and
covered with a large cover-glass. The glycerin does not mix with
the balsam, nor is it withdrawn from the object, which remains
perfectly clear. The method is applicable to sections of stems of
large size, such as tree ferns, palms, etc., whether woody or
herbaceous. Of course, suitable size of slides and covers have to
be obtained.

motes.

Relaxing Insects for Cabinet. — J. P. Mutch writes to the
EntofHologisfs Record that "Rectified wood naptha, obtainable from
any chemist, containing a trace of white shellac, say ten grains to
the ounce, applied to the underside of the extreme base of the
wings by means of a very fine sable brush, within a few seconds
renders the wings quite pliable ; the insect is then placed on the
setting-board and set to the required position, braces being used if
necessary. In from twelve to twenty-four hours the specimen is
ready for the cabinet, showing no trace of the manipulation it has
undergone. The shellac is recommended to prevent any possible
future springing or drooping, but the pure naptha produces an
equally satisfactory effect so far as the relaxing goes. The old
tedious process of damping may thus be obviated, and the delicate
colours left uninjured."

Fossil Microbes. — A recent communication to the Academie
des Sciences, M.M. Eeynault and Bertrand stated that in examining
some coprolites of the Permian period, they noted the presence of
a considerable quantity of microbes of different kinds — isolated
rodlets and diplo-bacilli, strepto-bacilli, vibrios, and filaments.
There were also mucedinea, with mycelium and detached spores.
The Permium bacterium is said not to resemble any of the forms

NOTES. 227

known to exist at present. M.M. Eeynault and Bertrand throw
out the suggestion that possibly there may be only one species of
bacterium which is polymorphic. — Brit. Med. Journal.

Impressions in Sulphur. — M. Lepirre, a French artist, states
that in demonstrating that sulphur melted at about 150^ can be
cooled in paper, he happened to use a lithographic card, of which
the edges were turned up. Upon taking away the card, it was dis-
covered that the lithographed characters were clearly and distinctly
impressed upon the cooled surface of the sulphur, remaining thus
after hard friction and washing. By repeated experiments in this
direction, he has succeeded in obtaining results of a very satisfac-
tory character, removing the paper each time by a mere washing
and rubbing process. It is found, in fact, that sulphur will receive
impressions from, and reproduce in a faithful manner, characters
or designs in ordinary graphite crayon, coloured crayon, writing
ink, typographical inks, china ink, hthographic inks — whether
coloured or uncoloured varieties — and others. He also states
that it will reproduce with remarkable exactitude maps.

According to Nature^ in a paper read at the Botanical Congress
at Genoa last year (1893), Professor Saccards calculates the num-
ber of species of plants at present known as 173,706, distributed
as follows: — Flowering plants, 105,231; ferns, 2,819; other vas-
cular cryptogams, 565 ; mosses, 4,609 ; hepaticae, 3,041 ; lichens,
5,600; fungi, 39,603; algae, 12,178. Professor Saccards thinks it
probable that the total number of existing species of fungi may
amount to 250,000, and that of all other species of plants to
135,000.

Adherence of Metals to Glass, etc. — C. Margot finds that
aluminium, magnesium, cadmium, and zinc possess the property of
marking glass and other substances containing much silica, in such
a way that neither rubbing nor ordinary washing will remove the
marks. Taking advantage of this curious property, he constructed
pencils and wheels of aluminium, by means of which designs can
be drawn upon glass, and it is understood that mirrors, etc., now
being sold in London, which reveal figures and various devices
when breathed upon, are prepared in this way. The effect is much
the same as when sketches are drawn on glass with French chalk,
but more permanent. — Arch. Soc. Phys. et Nat. de Geneve and
/ourn. de Pharni. (6), I., 263.

[ 228 ]

Practical Botany for Beginners. By F. O. Bowers, D.Sc,
F.R.S., etc. Cr. 8vo, pp. xi. — 275. (London : Macmillan & Co. 1894.)

This work contains, in an abridged form, the elementary and more essen-
tial parts of the t^xt of the larger Course of Practical Instruction in Botany.
We have, first, a List of Apparatus required for ordinary work in the botanical
laboratory ; Full Instructions for making Preparations and the Adjustment of
the Microscope for Work ; IL — Practical Exercises on the Structure of the
Vegetable Cell, involving Simple Methods of Preparation ; and III. — Common
Micro-Chemical Reactions ; followed by Practical Directions for the Study of
the types. There are two Appendices, giving a List of Reagents, their Prepa-
ration and Uses ; and a List of the Reactions of Bodies commonly found com-
posing the tissues of plants. A very useful book.

A Synopsis of the Genera and Species of Musece. By J. G.
Baker, F.R.S., F.L.S., etc. 8vo, pp. 34. (London: H. Frowde. 1893.)
Price 1/6 net.

This is a reprint from the Anjials of Botany^ VII., and gives a full descrip-
tion of the Genera, wSub-Genera, and Species of the MusecB, together with the
varieties and sub-species.

The Amateur's Handbook of Gardening, with a Calendar
of Garden Operations for each Month in the Year, with special contributions
by Eminent Gardeners. 8vo, pp. \iii. — 124. (Liverpool : Blake and Mac-
kenzie. 1894.)

Herein is contained a large amount of practical information — useful both to
the amateur and the practical gardener. It is said that every book which inter-
prets the secrets of gardening, and every chapter that elucidates the mysteries
of the cultivation of plants and flowers is a contribution to the wealth and hap-
piness of mankind, and such the author has endeavoured to make this book.
The Calendar of Gardening Operations will be found useful.

Die Naturlichen Pflanzenfamilien. By A. Engler and
K. Prantl. Parts 109 to 112. (Leipzig: Wilhelm Engelmann. London:
Williams and Norgate. 1894 — 95. )

The four parts before us of this exhaustive and beautifully illustrated work
contain descriptions of the Bignoniaceee, by K. Schumann ; the Mucorinese,
Entomophthorineae, Hemiascineae, Protoascineae, Protodiscineae, Ilelvellineae,
and Pezizineae, by J. Schroter ; the Araliaceae, by H. Harms ; the Junger-
maniaceae and Anthocerotaceae, by V. Schififner ; and the Musci, by Carl
Miiller. In these four parts there are 67 illustrations, composed of 433 figures.

A New English Dictionary on Historical Principles ;
founded mainly on the materials collected by the Philological Society. Edited
by Dr. James A. H. Murray, with the assistance of many scholars and men of
science. (Oxford: The Clarendon Press. London: Henry Frowde. )

The last part of this important work which has reached us covers the words
from Deceit to Deject, and forms part of Vol. III. The price of this part
is 2/6.

The Planet Earth : An Astronomical Introduction to Geo-
graphy. By Richard A. Gregory, F.R.A.S. Post 8vo, pp. viii. — 108.
(London: Macmillan and Co. 1894.)

The author of this plainly written and interesting little book observes, in

REVIEWS. 229

the Preface, that *' The scientific method of observation and induction should be
used in elementary astronomy as in other physical sciences. Celestial pheno-
mena must be observed before the theories that explain them can be properly
understood." The first chapter deals with star groups and the apparent diurnal
motion of the celestial sphere. In the second chapter it is shown that all the
phenomena previously described can be explained by the fact that the earth is
a globe in rotation. The determination of the size and mass of the earth is
the subject of the third chapter. Then comes an account of the apparent
motion of the planets. And, finally, it is shown in Chap. V. that the appear-
ances are easily explainable on the Copernican theory of the order of the uni-
verse. There are 36 illustrations.

Popular Science. By John Gall. Post 8vo, pp. 196
(London: Thomas Nelson and Son. 1895.)

This is another of those very useful ' ' Royal Handbooks of General Know-
ledge," in which the author brings together in Alphabetical or Dictionary form
a manual of useful information on various branches of science, his aim being to
pro\dde a handbook containing short summaries of facts and principles specially
adapted for beginners in the study of science. There are a great number of
illustrations.

Cassell's New Technical Educator. Monthly, price 6d.

No. 29 (the last part to hand) contains chapters on Steel and Iron ; Coach-
making ; Coal-mining ; Allotment and Cottage Gardening ; Design in Textile
Fabrics ; Building Construction ; Gothic Stonework ; Weaving ; Engineering
Workshop Practice ; Civil Engineering ; Gas and Oil Engines ; Printing ;
Electrical Engineering ; and Dyeing of Textile Fabrics. There are a number
of illustrations. The frontispiece, "Bridges," shows some of the essential
details in Bridge Construction.

Lectures on the Darwinian Theory, delivered by the late
Arthur Milnes Marshall, M.A., M.D., D.Sc, F.R.S., etc. Edited by C. F.
Marshall. 8vo, pp. xx. — 236. (London: David Nutt. 1894.)

We regret that in our notice of this book in our last issue we quoted the
price as 6/- ; it should have been ^jS.

A Text-Book of Sound. By Edmund Catchpool, B.Sc.

Lond. Crown 8vo, pp. viii. — 203. (London: W. B. Clive. 1894.) 3/6.

This is one of the University Tutorial Series. In it the author has tried to
keep in view the following aims : — I. — To include all the facts of which a know-
ledge is expected in elementary examinations ; II. — To present a clear picture
of the external physical processes which cause the sensation of sound ; and
III. — To keep before the reader the distinction between phrases which describe
actual processes or conditions, and those which, while they facilitate the predic-
tion of real processes and real phenomena, do not themselves stand for any
physiological condition or event. There are 73 illustrations.

Intensity Coils : How Made and How Used. By " Dyer."

Seventeenth edition. 8vo, pp. 79. (London : Perkin, Son, and Rayment,
99 Platton Garden. 1891.) Price i/-

This useful little book gives descriptions of Electric Light ; Electric Bells ;
Electric Motors ; The Telephone ; The Microphone ; and The Phonograph.
There are 184 illustrations.

Beginner's Guide to Photography, Showing How to Buy a
Camera and How to Use it. Crown 8vo, pp. 119.

230 REVIEWS.

The Magic Lantern : Its Construction and Use. Cr. 8vo,

pp. 82. (London : Perkin, Son, and Rayment, 99 Hatton Garden, E.G.)

Two very useful little books, bound in cloth and published at 6d. each ;
will be found to give a large amount of information on the subjects of which
they treat. They contain a number of illustrations.

Introduction to the Theory of Electricity, with numer-
ous examples. By Linnaeus Gumming, M.A. Third edition. Gr. 8vo, pp.
XV. — 326. (London: Macmillan and Co. 1885.)

In the work before us, geometrical, as distinguished from analytical
methods have been employed, and although a large pro]Dortion of the proposi-
tions involve the ideas of the Doctrine of Limits, the use of the notation of the
Galculus has been avoided. In the present (third) edition Ghap. i has been to
a great extent rewritten, and a chapter on Thermo-Electricity has been added.

The Medical Annual and Practitioner's Index : A Work of
Reference for Medical Practitioners. Gr. 8vo, pp. 650. (Bristol : J. Wright
and Go. London : Simpkin, Marshall, and Go. 1895.) Price 7/6.

The 13th annual issue of this well-known w^ork is before us, in production
of which some thirty-five editors and contributors have been engaged. This
volume, we believe, is in all respects equal to any of its predecessors. There
are 24 plates and 72 illustrations in the text. We notice that the treatment of
Diphtheria by the Anti-Toxic Serum has received special attention. The Dic-
tionary of New Remedies and Review of Therapeutic Progress for 1894
occupy the first place, and are followed by a chapter on Electro-Therapeutics
by A. D. Rockwell, A.M., M.D. ; Anti-Microbic Treatment, by Prof. Alfred
H. Garter, M.D., F.R.G.P. A Dictionary of New Treatment in Surgery
forms the Second Section. Section 3 treats of Sanitary Science, etc. etc.

Travaux d'Electrotherapie Gynecologique. Par Le Dr.

G. Apostoli. Vol. I. 8vo, pp. 720. (Paris : Societe d'editions Scientifiques.

18940

Dr. Apostoli has set himself the task of collecting together the most im-
portant papers that have appeared on his method of treating fibroid tumours,
etc., by electricity. In this first volume all the papers are by practitioners of
various nationalities, but translated into French, with footnotes by the Doctor.
If the results are as brilliant as described in the large number of cases whose
clinical history is minutely given, it would seem to be unjustifiable, if not cri-
minal, to subject a patient to the risk of hysterectomy without a previous trial
of this method.

Physiology for Beginners. By M. Foster, M.A., M.D.,

F.R.vS., and Lewis E. Shore, M.A., M.D. Gr. 8vo, pp. xii. — 241. (London:
Macmillan and Go. 1894.)

This finely illustrated Httle work is intended for those who, without any
previous knowledge of the subject, desire to begin the serious study of Physio-
logy. It is written in an elementary style, so as to form an introduction to
more advanced treatises ; a few chemical and physical facts are given in the
earlier chapters. There are upwards of a hundred good illustrations.

The Animal World : A Monthly Advocate of Humanity.
Vol. XXV. (London: S. W. Partridge and Go.)

The Animal World is issued by the Royal Society for the Prevention of
Gruelty to Animals. It is full of good pictures and thoroughly interesting
reading matter.

REVIEWS. 231

Band of Mercy (issued by the Royal Society for the Preven-
tion of Cruelty to Animals), Vol. XVI. Cr. 4to, pp. 96. (London : S. W.
Partridge and Co. 1894.;

All children who are fond of dumb animals must be pleased with this
prettily illustrated volume. Besides a number of pictures, music, etc. , it is full
of interesting tales and anecdotes relating to animals, birds, and insects.

The Book of the Fair. Parts VIII. and IX. (Chicago,

111., U.S.A.) Price $1.

This interesting publication, by Hubert Howe Bancroft, is the only work of
the kind published regarding the great Exposition. It is to be a full and com-
plete history and description of the World's Fair at Chicago, organisation,
buildings, and exhibits, covering the whole ground, and is as full in detail as
can be within the limits assigned — namely, 1,000 imperial folio pages of pic-
tures and print, to be issued in 25 parts, of 40 pages each. The publication began
soon after the opening of the Exposition. The Book of the Fair is published
by the Bancroft Company, Auditorium Building. Chicago.

These numbers commence with a description of the Woman's Depart-
ment, which is followed by an account of the Machinery. The section
allotted to Agriculture is commenced. The illustrations are very numerous
and most excellent.

The American Annual of Photography and Photographic
Times Almanack for 1895. 8^'*^> PP- 43^- (New York : The Scovill and
Adams Co.) Price : Stout paper covers, 50c. ; cloth, fi.

The volume before us is the Ninth Annual Volume of the series, of which
we feel bound to say each has been better than its predecessor. This volume,
besides a number of beautiful plates and some eighty or more illustrations in
the text, contains a large amount of interesting matter, written by men who
have earned for themselves honourable distinction in the history of photography.

European Butterflies and Moths. By W. F. Kirby,
F.L.S., F.E.S., etc. (London : Cassell and Co.) Price 6d. monthly.

This beautifully illustrated periodical has reached Part 10. Each part
contains a coloured plate, showing several species of Lepidoptera in their
various stages.

A Hand-book to the British Mammalia. By R. Lydekker,
B.A., F.R.S., V.P.G.S., etc. Edited by R. Bowdler Sharp, LL.D., F.L.S.,
etc. Crown 8vo, pp. xiv. — 339. (London: W. H. Allen & Co. 1895.) 6/-

This beautifully illustrated volume is one of "Allen's Naturalist's Library"
series, and gives descriptions, not only of those mammals now found in Britain,
but it contains brief notices of the species exterminated within historic period,
and a further section devoted to the fossil forms. The work is throughout
handsomely got up, both as to binding and letterpress, and contains in addi-
tion 32 excellent coloured plates.

A Hand-book to the Primates. By Henry O. Forbes,
L.L.D., F.Z.S., etc. Vols. I. and IL Cr. 8vo, pp. xv.— 286 and xv.— 296.
(London : W. H. Allen and Co. 1894.)

The first of these volumes contains an account of the Lemuroidea and the
Anthropoidea as far as the group of the Macaques of the family Cercopithecidce.
The second volume continues with the latter genus, and contains the rest of the
Monkeys and the Apes, as well as a summary of the geographical distribution
of the species of the order Primates. There are in the two volumes 29 coloured
plates and 8 coloured maps.

232 REVIEWS.

A Hand-book to the Marsupialia and Monotremata. By

Richard Lydekker, B.A., F.G.S., etc. Cr. 8vo, pp. xvii.— 302. (London:
W. H. Allen and Co. 1894.)

This volume of Allen's Naturalist's Library gives a scientific and yet popu-
lar account of the Australian Mammals. It also gives a description of some of
the more generally interesting extinct representatives of the Order. There are
in this volume 38 coloured plates and several wood engravings.

A Hand-book to the Birds of Great Britain. By R.

Bowdler Sharpe, LL.D. Vol. I. Cr. 8vo, pp. xxii. — 342. (London: W.
H. Allen and Co. 1894.)

The aim of the author has been to furnish the student with a useful guide,
which shall give him some idea of the characters, colour, geographical distribu-
tion, nests, and eggs of the birds of his native country, together with notes on
the habits of the different species. In this volume there are 31 coloured plates,
besides wood engravings.

A Hand-book to the Order Lepidoptera. By W. F.

Kirby, F.L.S., F.Ent.S., etc. Part L, Butterflies. Vol. I. Cr. 8vo, pp.
Ixxiv. — 261. (London: W. H. Allen and Co. 1894.)

This volume is devoted to the great family, Nymphalidce, with its many
sub-divisions, and includes about half the known butterflies, the British and
Foreign species being described in their proper order. The introduction to this
volume will be found very helpful to the lepidopterist, as it describes the ana-
tomy of the Butterfly and Moth, as well as gives hints on collecting and pre-
serving them.

We are exceedingly pleased with all the volumes we have seen of Allen's
"Naturalist's Library." Every volume is written in a popular and thoroughly
interesting manner, and is beautifully illustrated ; the binding also is handsome
and good. The price of each volume, we believe, is 6/- We unhesitatingly
recommend all our readers to secure a set of this work.

Science Progress. No. 13, March, 1895. (London: The

Scientific Press.) Price 2/6, or 25/- per annum, post free.

The first part of Vol. III. contains the following articles : — Antitoxin, by
E. Klein, M.D., F.R.S. ; Foreign Work amongst the Older Rocks, by J. E.
Mare, F.R.S. ; Insular Floras, Part IV., by W. Bottingley Hemsley, F.R.S. ;
Peptone, by W. D. Halhburton, M.D., F.R.S. ; Budding in Tunicata, by W.
Garstang, M.A. ; The Reserve Material of Plants (continued), by J. Reynolds
Green, M.A., D.Sc. ; with Appendices: — I., Notices of Books ; II., Chemical
Literature for January, 1895.

The Story of the Stars Simply Told for General Readers.
By George F. Chambers, F.R.A.S. Foolscap 8vo, pp. 192. (London:
George Newnes. 1895.) Price i/-

In writing this little book, Mr. Chambers thought of those rapidly growing
thousands of men and women of all ranks who are manifesting an interest in
the facts and truths of Nature and Physical Science. He treats of the Bril-
liancy and Distances of the Stars, their grouping into Constellations, the num-
ber of the Stars, etc. etc. It is a very readable book, and supplies a large
amount of information.

The Model Steam-Engine : How to Buy, How to Use, and
How to Construct. By " A Steady Stoker." Cr. 8vo, pp. 96. (London :
Houlston and Sons. 1895.) Price i/-

All boys are interested in Steam-Engines. In this little book they will find
all the various parts fully described, with instructions for constructing one on a
small scale for themselves.

[ 233 ]

^be 3nfluence of Xigbt on ilfe.

By W. Thomson.

'S

92i»-

HE object of this paper is to gather together from
the world of nature a few examples of the influence
which light exerts upon life, so that by the con-
sideration of its effects in individual instances we
may the more easily be led to a more perfect
appreciation of its influence upon all living things.
-^/J^V^- That light plays an important part in the present
pjV\'^ economy is, of course, admitted at once by every-
one; but it requires, at least by some of us, a little
consideration before we can thoroughly grasp the full truth of
such a statement as that made by Prof. Frankland in the Nine-
teenth Century for May, 1894 : — "Almost every exhibition of force
with which we are acquainted on the earth is wholly due, either
directly or indirectly, to the influence of the sun through those
rays which reach us after traversing 93,000,000 miles of space.
Of the whole energy sent forth by the sun, we know that only an
excessively minute fraction — not more than one twenty-two hundred
millionth part (1/2,200,000,000) — is intercepted by the earth at all.
But in spite of the enormous distance traversed and the small
fraction of this radiant energy which we are only able to 'trap,'
modern science has shown us that we owe almost everything that
we have to its agency, and the remarkable manner in which it
controls the phenomena of our earth is daily receiving fresh illus-
tration and support."

The commonest phenomena are very often those to which we
give the least attention. When an earthquake suddenly occurs,
men are forced to give heed to it; but as the sun continues from
day to day exerting its mighty influence, and silently keeping in
continual motion the wheels of life, there are few who regard it
with more than a common observation. Night follows day, week
succeeds week, the sun rises, the sun sets, and few are there who
consider for one moment what would take place if the sun set
and rose no more (that is, if continual night were to be the order
of things) ; or what would take place if the sun rose and set no

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. r

234 THE INFLUENCE OF LIGHT ON LIFE,

more (that is, if continual day supplanted the alternating order of
day and night).

As we look round about upon the gardens of the world, and
observe the green leaves of the trees, the herbage of the fields, the
beautifully coloured flowers, and the myriad varieties of form into
which the vegetable kingdom is divided, we see them as they have
grown and been developed under the influence of day and night-
The same also applies to the animal world. In a general way, we
may say that all animals and all plants spend half their lives in
light and half in darkness, and that their present condition has
been arrived at under the influence of an equal amount of light
and darkness. Now, as each plant requires a certain quantity of
light for its successful growth, it is pretty evident that if that quan-
tity be unduly increased or unduly decreased, the consequences
thereof may be of a serious nature to the plant. By considering
what takes place, either in exceptional cases in the world of nature
or by actual experiment, when the norinal quantity of Hght is
greatly interfered with, we shall, perhaps better than in any other
way, understand the influence of light, and learn how important it
is that in our daily life we should not forget the beneficial results
which follow from a right relation between the rays of the sun and
the living things upon this planet, or ignore the consequences
which may follow if that relation be not attended to. The force
or reason of these statements may perhaps become more manifest
as we proceed.

The carbon which a plant requires in order to build up its cells
and tissues is obtained from the carbonic acid gas which is con-
tained in the air. Carbonic acid gas, as we all know, consists of
carbon and oxygen; but as it is only the carbon which the plant
requires, it is therefore necessary that the compound should be
broken up, so that the requisite carbon may be obtained. Now,
living plants possess this wonderful power, and are able to extract
the carbon and set free the oxygen, but they are only able to exert
this power under the influence of light. During the day, therefore,
this process goes on without interruption ; but during the night the
plant is no longer able to continue it, as the influencing power, the
light, is of course absent. No sooner, however, does the morning
light once more bathe the plant than once again it is enabled to
appropriate the carbon.

THE INFLUENCE OF LIGHT ON LIFE. 235

If we SOW some seeds in a pot and place it in a dark cupboard
we shall find that in due season these seeds will sprout, but we shall
also find that the small seed-leaves will remain of a yellowish colour.
If left in the dark, the young plants will, perhaps, lengthen out a
little, but, after the food which was stored up in the seed has been
exhausted, no increase of the plant's substance will lake place.
They will become swollen with water and soon droop down and
die. If at the same time as we make that experiment we also
place a pot containing seeds in the Hght, we shall find that the
young plants will hea.r green leaves, and that, instead of becoming
water-logged and limp, they will every day fix more carbon in their
tissues, so that the plant substance will daily increase. In these
two experiments we have the same seeds, the same quantity of
water provided, and the same air, containing in each case the same
quantity of carbonic acid ; but the great difference in the circum-
stances is, of course, that in one case we have no light at all and
the plant dies, while in the other case the plant enjoys the influence
of the mysterious light, and therefore lives and grows. If we
removed the plant which was trying to grow in the dark into the
light, we should find that its colourless leaves would soon become
green, and that in every way the plant would turn from its state of
sickness to one of verdant health. The seeds germinated in the
dark, of course, because the necessary food was present in the
seed, and light was therefore not required for the fixation of
carbon. Indeed, light is objectionable at that stage, as it tends to
fix the carbonic acid which the young sprout wishes to throw off.

The same proof of the necessity of light for plants is obtained
by exposing one glass of spring water to the sunshine, and hiding
another one in a dark chamber. In the former glass, green films
of algae life will by-and-by appear, owing to the action of light on
the germs which were present in the water, whereas, as might be
expected, no such growth will appear in the other glass. From
these simple experiments we see that it is absolutely necessary, in
order to have vegetation, that we must have light, and we find our
experiments fully corroborated in Nature, for in coal-mines and
caves where there is no light at all there is no plant life at all.
We may just call to mind, in passing, that in the cultivation of
.celery the altering effect of darkness is taken advantage of; the

236 THE INFLUENCE OF LIGHT ON LIFE.

bottom part of the plant's stem is protected from the light, and is
thereby rendered more succulent and desirable as an article of
food.

Different species of plants require different amounts of light.
Some are very greedy and some are content with a very little
indeed. In the deepest parts of the sea, where perpetual darkness
reigns, we are told that there are no plants at all ; but in shallower
waters where there is a certain degree of light, although the quan-
tity may be very small, seaweeds are to be found in abundance.
In Messrs. Kerner and Oliver's book on The Natural History of
Plants^ a certain moss (Hookeria splendens) is referred to, which
lives chiefly in hollow tree-trunks. The light in such situations is
necessarily often very feeble, yet this moss is noticeable for its
glossy green. On examination the leaves are found to be very thin
and delicate, but the cells of the leaves which are turned to receive
the scanty light are convex and act somewhat like lenses, and
condense the light on to the granules of chlorophyll which He
behind these convex cells. By such a beautiful contrivance as
this are these humble plants able to concentrate sufficient light
to enable them to secure for themselves the carbon which they
require.

We all know that in shady nooks and sheltered corners quite
different species of plants may be found from those which may be
found in exposed places and in the full blaze of sunlight. No one,
for instance, would ever think of looking for a rose in the darkest
parts of the woods, nor would we think of looking for the health-
iest ferns or mosses in such places as would be most congenial to
the rose. We may find fungi in dark — indeed, altogether dark —
places; but then we know that fungi are different from other plants,
as they do not produce chlorophyll, they being producers of car-
bonic acid instead of decomposers of it.

We have now seen that the presence of a moderate supply of
light has an influence in sustaining the life of certain plants, and
even in bringing about a luxuriance such as we often see in grottoes
of ferns ; we have seen that even a very little supply of light indeed
has an influence in sustaining such plants as possess the power of
gathering up the scanty rays ; and we have also seen that when the
supply /^//j altogether^ then life ceases.

THE INFLUENCE OF LIGHT ON LIFE. 237

We shall now consider what would take place if a plant were
kept continually in light, or if it received a great deal more light
than the normal quantity. As we cannot very well, ourselves,
perform an experiment to prove what happens, we must borrow
from Professor Stokes. Three pots of mustard-seed were sown at
the same time. One was kept under the usual conditions of day-
light by day and darkness by night ; another was kept in darkness
during the day and was exposed to the electric light during the
night. At the end of the experiment the plants in these two pots
were found to be much alike. The third pot, however, was
exposed to daylight during the day and to the electric light during
the night. At the end of the experiments the plants in this pot
were found to be stouter looking, to have larger leaves, and to be
of a darker green than the plants in the other two pots, but they
were not so tall. We gather from this experiment that the plants
in the third pot were hastened forward by having gathered into a
short space of time an aqiount of light which, in the ordinary
course of things, would have been spread over a much longer
period.

Professor Bailey, an American, has recently been making
numerous experiments as to the influence of the electric light upon
plants, and he has found that when plants were kept under con-
tinuous light — that is, sunlight by day and electric light by night —
growth was expedited. In the case of some cabbages grown under
these conditions, maturity was reached about two weeks before
others which were cultivated under the usual conditions. It was
also observed that if plants were placed too near the electric light
it proved very injurious to them. The electric light contains
certain rays which are harmful to vegetation, but it has been proved
that this injurious property may be avoided to a great extent by
passing the light through transparent glass. These experiments
show that the electric light affects different plants in different ways,
but that the general result is a hastening of the growth. Such an
unnatural state of things, however, must surely prove injurious to
the plant if continued for very long without a sufficient period of
rest or darkness being allowed.

Dr. Carpenter tells us that the same annual plant, in arriving
at its full development, requires everywhere the same amount of

238 THE INFLUENCE OF LIGHT ON LIFE.

light and heat, so that at the equator it will come to maturity so
much the sooner. The more the light and heat the quicker they
obtain the sufficient quantity for their development. It is worthy
of note that, though, as is the case when fruit-trees are transported
from this country to another clime of greater light and heat, a
great acceleration takes place in the growth, the period of life is
much shortened. Prof. Stokes points out how rapidly vegetation
grows in the Arctic regions when summer has fairly set in, and
how that rapidity is the result of the long summer days, the sun,
indeed, remaining above the horizon for the greater part of the
twenty-four hours. Vegetation in those northern latitudes, how-
ever, gets a long rest during the winter, and thus is compensated
for the extra activity induced by the continuous sunlight of the
summer days.

It would, perhaps, now be well to call attention to the beha-
viour of chlorophyll granules under varying quantities of light, and
when we consider how directly dependent upon light the chloro-
phyll is, and how entirely the chlorophyll depends upon that
influence in order to perform its work and supply the plant with
nutriment, we are not altogether surprised to find that the granules
endeavour to accommodate themselves to any changes which may
occur. Those who have closely examined their behaviour inform
us that the granules in some cases alter their shapes, while in other
cases they arrange themselves in the cells in positions which are
most suitable to receive the proper quantity of light. If the light
is just sufficient for their needs, the granules will (as in the Ivy-
leaved Duckweed) spread themselves over the cell- walls (Fig. i).

If the light is altogether absent, then the granules crowd up
close under the epidermis, as though striving hard to get nearer to
the source of light which has been temporarily shut off from them,
and take up a position as exposes the largest surface possible
(see Fig. 2). If, however, the light is too strong, then the granules
station themselves along the upright walls — a position which, it is evi-
dent, will be most conducive to shelter, as thereby the least possible
surface of chlorophyll will be exposed (Fig. 3). These movernents
of the protoplasm or chlorophyll granules are most interesting, and
the matter becomes even more interesting when we remember that
the leaves, twigs, and even branches of plants also take up posi-
tions in accordance with the degree of illumination.

THE INFLUENCE OF LIGHT ON LIFE. 239

The tendency of the growth of a plant is always in the direc-
tion of the most favourable light. Leaves and twigs all grow in
such a manner that they will not, in an undue degree, interfere
with the proper supply of light to the other leaves and twigs on the
same shrub or tree. We all know that when we look beneath the
surface of a clump of ivy or thick bushy shrub, we find that the
green leaves are mostly all outside, spreading themselves out in the
sunshine. Anyone who has grown a geranium in the house knows
very well that the leaves, and indeed the whole plant, bend
towards the window in search of light, and microscopists know that
if a tube containing Volvox globator be left standing in the room
for a short while, all the organisms wall congregate on that side of
the tube which is turned towards the light. In the same way does
vegetation everywhere grow according to the light, and take up a
position in the shade or in the sun according as its nature demands.

CDQoocDoc ^^^^D^^jc ro'cpaaor

Fig. I. Fig. 2. Fig. 3.

Where an excess of carbonic acid is present in the air, a plant
can bear a greater amount of sunshine than is possible under ordi-
nary circumstances. Many plants, however, are unable to stand
an excessive light and so perish, but some species are provided
with protection. For instance,* on the Mediterranean shores, the
leaves and stems of plants which grow on exposed situations are
provided with coverings of hair, whereby the green is almost
hidden from sight, which serve as a protection from the fierce
light of the sun. In some plants a violet colouring matter is found
near the surface of the leaves, so that, coming between the chloro-
phyll and the light, the excess of illumination is counteracted.
Many other devices with the same object have been observed, but
these will suffice for our purpose. That these hairs and the colour-
ing matter are for protection from excess of light is evident, for
when the same species are grown in diffused light, the hairs and

*See Kerner and Oliver.

240 THE INFLUENCE OF LIGHT ON LIFE.

colouring matter are not developed. From this we can see that
light has a good deal to do with the distribution of plants, as,
unless they are provided with protective appliances, they will never
be able to grow in any situation where the light exceeds a certain
fixed standard.

The weed which grows in ponds is often of a less green colour
on the surface of the pond than it is a little beneath the surface,
and this is due to the bleaching action of the sun, for when the
light is very strong the chlorophyll loses its bright green colour.
If a piece of black paper be fixed on a green leaf exposed to
strong light, it will protect the part so covered, and when the paper
is again removed the places which were uncovered will be seen to
be quite pale in comparison to the part which was sheltered. It is
to this bleaching action of light that the disappearance of the
green in autumn is said to be due. I steeped several ivy leaves in
methylated spirits and obtained a beautiful bright green solution,
due, of course, to the chlorophyll having been dissolved out of the
cells. Part of this solution was then exposed to the light, and in
a day or two I found that the green colour had quite disappeared,
and that the liquid had assumed a brownish hue. This, then, is
the bleaching action just referred to, and which is very noticeable
in cabbage and other leaves which have become separated from
the stock.

Some plants turn the edges of their leaves to the light when it
is too strong, and when the quantity is agreeable they turn the flat
surfaces to the lights an arrangement which, like other contrivances
to avoid undue light — such as the folding up of leaves, etc. — keeps
down at the same time an unnecessary waste of moisture, for
it is through the light that the stomata are caused to open
and allow the process of exhalation to proceed. As too little
light tends to impede exhalation, too much light tends to cause
danger in exactly the opposite direction. It is light which causes
unripe or acid fruit to be changed into ripe or sweet fruit ; and it
is light, as we so well know, that controls the opening and closing
of the daisy, or "day's eye," and so many other flowers of the
field.

Experiments have been made with a view of determining which
rays of the spectrum produce the greatest influence on plants, and

THE INFLUENCE OF LIGHT ON LIFE. 241

it has been ascertained that the red, yellow, and orange rays are the
most powerful in causing growth, whereas the blue and violet rays
are almost entirely without effect in inducing the chlorophyll to
perform its function. On the 26th January I sowed some seeds
(canary, hemp, and rape) on pieces of flannel kept moist with
water. These seeds were then exposed to the light under different
coloured glasses, with the following result : — Under the yellow
glass the growth was strong and rapid ; under the red it was nearly
the same ; under the green the growth was, during part of the
time, very much delayed, but eventually it gained strength ; and
under the blue the growth was the slowest, and the green of the
plants did not appear to be of so bright a hue as in the other
cases. Although the green glass was the most transparent, yet the
growth was not nearly so rapid as under the much less transparent
red glass. Prof. Stokes ascribes to the greenish-yellow the most
active power, but my experiments, just quoted, appear to support
Messrs. Kerner and Oliver's conclusions that the red, yellow, and
orange rays are those which the chlorophyll requires to fulfil its
functions. It should, perhaps, be remarked that experiments with
coloured glasses are not so conclusive as experiments performed
with colour rays obtained directly from a prism.

There seems, however, to be no end to the instances which might
be quoted of the influence of light upon plant life ; indeed, the
greater puzzle seems to be to find something which is not due to its
influence. Our present object, however, besides trying to show how
plant-life is altogether dependent on light, is to endeavour more par-
ticularly to show that an increase or a decrease in the normal amount
of light, or an alteration in its quality, has a great influence on
plants; that there is a certain fixed quantity which is most acceptable
to each species, and that when that fixed quantity is exceeded or
diminished to any great extent, evil consequences must follow. I
think that these conclusions may with safety be deduced from
what has just been said, and it therefore seems reasonable to con-
clude that, if investigations are properly conducted, we ought to
be able to ascertain with a great degree of nicety, the exact supply
that is best for each species, and so be able to measure out, in cul-
tivating a plant, just as much as will exert the highest and best
influence.

242 THE INFLUENCE OF LIGHT ON LIFE.

When we refer to the greatest influence for good which light
exerts on plant life, we are almost naturally led to ask, Is it pos-
sible that light also exerts an influence on animal life ? And if so,
surely there must also be in that kingdom a certain measure of the
subtle influence which also proves most beneficial.

Such a consideration, then, forms the second part of our paper.
We have just seen that light is essential to the very life of a plant,
but it can scarcely be said in exactly the same way that light is
absolutely essential to the existence of all animals. It is true that
animals are altogether dependent upon plants, either directly or
indirectly, for the supply of food, and, as plants are altogether
dependent on light, therefore animals could not exist without hght,
but, putting that indirect dependence to one side, we do not find
that the total withdrawal of light is always followed by the death
of the creature in the same way as we found that the total with-
drawal was the death of the plant.

In animals we have no chlorophyll to deal with, qxcqy>^ perhaps
in a few instances, such as Hydfa vtfidis, Euglena, and Stentor;
and, therefore, if we find hght agreeable or necessary to the life of
an animal, it must be for some other reason than that for which a
plant requires it. In Professor Semper's book on Animal Life
(International Scientific Series), he goes so far as to suggest that
animals may be at least as dependent as plants on the direct influ-
ence of light, although the nature of the relation may be altogether
different. I daresay that most of us have read the story regarding
Van Helmont, a celebrated alchemist doctor in the time of Louis
XIV., and the wonderful power which he attributed to the rays of
the sun. " Scoop out," he wrote, " a hole in a brick ; put into it
sweet basil, crushed; lay a second brick upon the first, so that the
hole may be perfectly covered. Expose the two bricks to the sun.
and at the end of a few days the smell of the sweet basil, acting
as a ferment, wiU change the herb into real scorpions." Present-
day science scarcely ascribes such an influence as that to the sun's
light ; but it certainly does present us with many wonderful results,
and results which I daresay would have surprised Van Helmont
quite as much as his production of scorpions surprises us.

Dr. Carpenter, in his Physiology^ states that if cockroaches are
reared in an entire absence of fight, they will grow all right, but

THE INFLUENCE OF LIGHT ON LIFE. 243

they will be colourless. Whether that is really the fact or not, I
can't quite say, as I have been unable to find any other experiment
confirming it. In a somewhat old edition of the Encyclopcedta
Britafinica an experiment by a Dr. Edwards is quoted. Dr.
Edwards said that if the spawn of frogs be kept in total darkness,
the eggs will not hatch, and further that if tadpoles be kept in the
dark they will not develop into the mature frog. They will
increase in weight, but their tadpole state will be preserved. This
experiment seems almost too simple to allow of any mistake being
made, but that we cannot pin our faith to it implicitly is manifest
when we find Prof Semper quoting an almost similar experiment,
in which the larvae of frogs were reared in completely dark cellars
without discovering any difference in their development beyond a
retardation due to the diminished warmth. If it were only the
proper season of the year, we could easily prove which of these
two scientific gentlemen is correct ; but, in the meantime, we
must just set the two experiments like an equal negative and posi-
tive quantity against each other. In support of the non-develop-
ment of frog-spawn in the dark, it is only fair to say that Dr.
Carpenter states that the eggs of silkworms are not hatched nearly
so well in the dark as in the light.

If, however, these experiments are somewhat inconclusive, we
can get more certain information by examining the creatures which
are found inhabiting mines or caves. In some of these caves —
as, for instance, the famous caves of Kentucky — the darkness is
complete, a single ray of light never entering their silent depths.
Travellers who have visited such places tell us strange stories of
the sights which are there to be seen. At present we do not
concern ourselves with the caves themselves. But let us suppose
that we have quitted the daylight and dived into the dark passage
which leads to the innermost recesses of some great cave. After
passing, in our journey, many mysterious passages which strike
away into unknown darkness, and crossing great chasms yawning
into unfathomable depths, we are at last led by our guide into a
central hall, and there, by the aid of our torches, is seen a silent
lake occupying the centre. In the dark waters of that lake the
traveller may see a number of strange-looking fish gliding swiftly
about. We are told that the skin of these fish is of a whitish

244 THE INFLUENCE OF LIGHT ON LIFE.

fleshy colour and transparent enough to allow of the heart and
liver being seen within. They have four legs and a long eel-like
body, and they breathe both by gills and lungs. On closer exami-
nation two black spots may be seen upon the head. These black
spots are situated at some distance beneath the skin, and prove on
investigation to be all that remains of the creature's eyes. For
generations these animals have lived in perpetual darkness, and as
they have therefore never had opportunity to exercise the power
of their eyes the faculty of vision has been lost, and by the law of
degeneration the very organ itself has been changed, bidding fair
to be, in the course of time, entirely absorbed or extinguished as
unnecessary. We thus see at once that certain hfe is possible
under the entire absence of light, but we also see that vital
changes have been made.

Other animals, besides those just referred to, are also to be
found in dark caves, and all of them either half-blind or altogether
bUnd. A spider discovered in these regions has developed very
long antennae, thus making up for its loss of sight by unusually
prominent powers of touch. A blind rat, also, which inhabits
those caves has grown very long and sensitive whiskers. These
are undoubtedly very strong evidences of the result caused by the
absence of light, and they are strengthened by the finding of
blind fish at very great depths in the sea where no light ever finds
its way. Like most observations of this kind, there are several
exceptions, but they do not affect us at present, as we are dealing
more particularly with the general question, which is clear enough.

In the caves just referred to, it is noted further that the pre-
vailing colour of the animals and insects is white — a condition
which, it seems fair to conclude, has been brought about by their
continual dwelling in such a dark abode. We know, however,
that the colours of animals are not dependent entirely upon light
for their production, as, in the case of a brightly painted butterfly,
it is complete in its beauty as soon as it leaves the chrysalis stage,
although the pupa may have been buried in the earth, and, there-
fore, been developed quite in the dark. But if this butterfly spent
all its days in the dark, and succeeding generations did the same,
we should no doubt find that its colours would disappear in the
course of time, till, if it could exist at all, nothing but a whitish

THE INFLUENCE OF LIGHT ON LIFE. 245

sort of tinge would remain. From this we may gather that a tem-
porary withdrawal of light is not always followed by a loss of the
colour-forming power, but that a continued absence of it, as the
perpetual darkness of caves, destroys it and bleaches the creatures.
It may just be mentioned in passing that it is said that the pigment
colours in flowers (not the chlorophyll, of course) can be produced
in darkness.

Now, although we find it stated that darkness does not, imme-
diately, hinder the production of colours in animals, yet there can
be little doubt that light has an influence, greater or less, in
affecting the brilliance or intensity of the colours. That such is
the case appears pretty manifest when we contrast the splendid
colours of many of the tropical insects and animals with the more
sombre hues of the creatures in this part of the world, and
remember how much more powerful is the influence of the solar
rays in the tropics than it is with us. We seem almost naturally
to link the brilliance of tropical light with the brilliance of the
plumage of the tropical birds which we are acquainted with on the
shelves of museums. If some of these birds, with their rich and
gorgeous plumage, be brought to and reared in this country under
artificial heat. Dr. Carpenter tells us that they are much longer in
attaining their full degree of colour, and that they never exhibit
the same amount of brightness as when brought up under the
influence of the tropical sun.

But we do not require to take birds as an example of the
variation in colour according to the light, for we only require to
compare the skin of any man whom we may find working in the
fields beneath the summer's sun with our own skin, and we at once
see a very great difference. We know also that a very short expo-
sure to the sun is sufficient to spangle the faces of some people
with freckles, and that we are not at all surprised when a traveller
returns from foreign climes with his complexion changed into a
very decided brown hue.

To refer again to Dr. Carpenter, he says that there can be no

doubt that the prolonged influence of light, during one generation

after another, tends to make such a hue permanent. Whether

this accounts altogether for the black skins of negroes or not, we

will not stay to consider, as other matters would have to be dealt

246 THE INFLUENCE OF LIGHT ON LIFE.

with which are not connected with our subject; but we may just
remark that there does not appear to be any very prominent reason
why we should not ascribe the blackness of skin to be due to a
long-continued habitation in sunny regions. At any rate, we know
that we can obtain brown hues from the sun's influence, and that
anyone who is for long shut out from the light, as a prisoner in a
dark cell or a workman in a mine, becomes pasty-looking and
very pale-faced.

Now, leaving out of consideration altogether Darwin's theory
of Natural and Sexual Selection as the cause of colours in animals,
we can fairly consider it established that light has to a certain
extent a direct influence on the pigment. Professor Semper
calls attention to a most interesting influence which light exerts on
some animals in an indirect way. The animals referred to are
those which have the power of changing their colour to suit the
surroundings, and the Professor asserts that this is brought about
by the influence of the surrounding light acting upon the retina of
the eye. For instance, if a fish possessing this power rests over
red sand, then the impression of the red through the eye upon the
brain will cause the brain to effect certain contractions in the
pigment cells on the surface of the creature's body, whereby all the
different coloured pigment-cells will be contracted except the red
ones, and the fish will consequently bear then a similarity to the
red sand. That, at any rate, is the explanation which has been
put forward, and by that theory it is supposed that the red light is
unable to excite the red pigment-cells (chromatophores) to con-
tract. And so with other colours. If the Hght is blue, then all
the pigment-cells except the blue ones will contract, and the skin
will thus be blue.

It is somewhat interesting to find Darwin, in his Descent of
Matiy explaining that the colours of the shells of some MoUusca
are no doubt influenced, to a certain extent, by the amount of
light, and pointing out that the lower surface of the shells is
generally less highly coloured than the upper and exposed surface.
When we thus pass in review the influence which light, or the
absence of light, has in altering colours, in changing, it may be,
the manner of a creature's hfe, in causing the degeneration of the
organ of vision, and even in preventing development or causing

THE INFLUENCE OF LIGHT ON LIFE. 247

death, we are not far wrong if we presume that therefore the deli-
cate organisation of man and the mystic power of his mind will
also be influenced according to the quality or quantity of the light.

It is common experience that a person's spirits are depressed
or elevated according to the weather. If the day is very dark and
cloudy, then with many people everything is dismal and the feeling
is that of oppression. It " disposes much all hearts to sadness,"
as Cowper wrote. Gloomy clouds fill the mind, and there is a
general sensation of misery ; indeed, I think I have seen it stated
somewhere that during a long season of dark days the number of
suicide cases was increased. No sooner, however, does the dark-
ness give way and the sun once more shine forth, than its cheering
influence is at once manifest. Men's faces wear a more peaceful
and happy expression, and a feeling of satisfaction pervades their
being. So pleasant, indeed, is the light to man that to " bask in
the sunshine " is regarded by most as a high species of enjoyment.
If we had to live for any extended period in darkness, we should
no doubt become very wretched, if, indeed, we could exist at all.
A good hght by day and darkness by night is best suited to our
requirements, and when this natural order is interfered with then
we suffer accordingly.

When the night is unduly prolonged, as happens during the
winter season in the Arctic regions, we find that it is altogether
objectionable. Dr. Kane, in his diary of his Arctic Expedition,
has given some very interesting records of his experience of the
long Arctic winter. He wrote : — " Noonday and midnight are
alike, and except a vague glimmer in the sky that seems to define
the hill outlines to the south, we have nothing to tell us that this
Arctic world has a sun. The influence of this long, intense dark-
ness was most depressing. Even our dogs, although the greater
part of them were natives of the Arctic circle, were unable to
withstand it. Most of them died from an anomalous form of
disease, to which I am satisfied the absence of light contributed
as much as the extreme cold."

In contrast to the baneful influence of the absence of light, we
must refer to the opinion which has been expressed, that the well-
formed bodies of many tribes where little clothing is worn is due
to the large amount of sunshine which is thus allowed to operate

248 THE INFLUENCE OF LIGHT ON LIFE.

freely upon them, and that the noted absence of deformity is also
in some measure due to the same cause. Although many causes
may, no doubt, assist in such results, yet light is supposed to play
an important part. It has been proved by experiments that when
infants are kept in the dark their temperature is decreased, and
this must affect their growth. If we wish to find ill-formed bodies
we shall more surely come across them in narrow, dark streets and
confined situations than amongst the individuals of a nomadic
tribe, who spend their existence in the open air. If light, there-
fore, has an influence on a healthy body, we should reason correctly
if we concluded that it has also an influence on an unhealthy body.

Dr. Carpenter quotes the report of a medical gentleman, who
observed that in a large barracks at St. Petersburg the cases of
disease were three times as numerous on the dark side of the
building as they were on the light side ; and, further, he tells us
that it has been found that, in a certain London hospital, residence
in the wards which looked south was much more conducive to the
welfare of the patients than residence in the wards which looked
north.

I read some time ago that Insanity had been treated by taking
advantage of the influence of light, and after enquiry in a reliable
quarter was obliged with the following information : — " Dr. Pritchard
Davies, who has made experiments on the photo-chromatic treat-
ment of Insanity, has expressed his opinion as follows : — * Failures
are very many and far outnumber the cures. The list of those
upon whom it had no effect whatever is a very long one, and in
many the improvement was but slight. Still, I am convinced that
it has materially benefited some, and those not slight cases, but
cases which had resisted other treatment and given great trouble.'
Dr. Davies believes that it is most beneficial in hysteria, moral
insanity, acute mania, and even in cases where, though the disease
is of long standing, there are lucid intervals. The experiments
were made in the blue room." It appears that the system consists,
so far as I can make out, in keeping the patients in a room in
which all the light is of a certain colour. Though the result is not
very satisfactory, yet it is sufficient for our present purpose, as it
shows us that this light treatment has some effect, and it hints to
us that it may be possible, if only the right key could be found as

THE INFLUENCE OF LIGHT ON LIFE 249

to quality and quantity, to literally use light beneficially in the
treatment of the Insane. That coloured light should have any
effect at all may perhaps appear a little strange until enquired into.

Without entering into the question of the wave-lengths and
degrees of refrangibility of the different colour-rays of the spectrum,
it will be sufficient to call attention to one or two examples of the
influence of coloured light. Turkeys are irritated by red and bulls
also, a fact which gladiators take advantage of, we are told, when
they wish to excite to rage the bulls with which they are to combat.
If, then, red excites some animals, why should not some other
colour soothe them ? In the treatment of the Insane, just men-
tioned, red is recognised as an exciting colour, blue and violet as
saddening ones, and green as a soothing one.

Prof. Semper informs us that under green light frogs disengage
more carbonic acid than under a red light; and that under a green
Hght tadpoles will not develop into frogs ; while white rabbits are
said to be most certainly and easily reared in a white reflected
light. Sir John Lubbock found that Water-Fleas (Daphnia) pre-
ferred yellow or green light to white light, and in his book on Ants
and Bees he quotes a great many experiments which he had made
with the view of ascertaining which colours were most preferred
by ants. We cannot here quote the different results he obtained
under varying conditions, but we can relate one of the experiments.
He covered the box which contained the ants with strips of
coloured glass — green, yellow, red, and violet — and then counted
the number of ants which took up their position under the various
colours. After half-an-hour he changed the position of the glass
slips, putting the red where the green was before, and so on, and
the ants then re-arranged themselves. In twelve experiments it
was found that the total number which stayed under the red glass
was 890, under the green 544, under the yellow 495, and under
the violet only 5. Although the violet glass was as dark in shade
as the red, and darker than the green, yet it is remarkable that the
ants had a decided objection to the violet light. As a rule. Sir
John found that the ants collected in the shadiest place in the box,
but they did not prefer the shade of violet glass, although it was
much more shady to our eyes than the green or yellow glass.

International Journal of Microscopy and Natural Science.

Third Series. Vol V. s

250 THE INFLUENCE OF LIGHT ON LIFE.

These references are perhaps sufficient to show that different
coloured lights influence animals in different ways.

It is scarcely necessary to mention, before we pass to another
matter, the influence of darkness in inducing sleep among so many
animals. Even when darkness comes on at unusual times — such
as during an eclipse of the sun — it has been noticed that the birds
ceased singing and, like many other creatures, went to sleep.

I now wish to place before you a brief resume of some recent
investigations on the influence of light on certain micro-organisms
as set forth by Professor Percy Frankland. Although the effects
which have already been mentioned are interesting, yet the follow-
ing results of sunlight upon microbes are almost more interesting
and wonderful. Messrs. Downes and Blunt put some test-tubes,
containing a liquid which was swarming with bacteria, in such a
position that the tubes were exposed to the direct rays of the sun
for several hours daily. The result of this exposure was that when
the light was most favourable the development of the bacteria was
entirely prevented, and when the light was not so strong the growth
of the microbes was only retarded. In tubes which had been
screened from the light, the bacteria were found to have increased
in numbers. The direct rays of the sun were proved to be most
effectual in destroying the organisms, but diffused daylight was
found to have a considerable damaging effect upon them.

As a result of experiments which were made with a view of
finding out which rays were most active in bringing about such a
novel effect, it was ascertained that bacteria which were exposed to
the blue and violet rays had their growth entirely prevented,
whereas those which were exposed to the red rays of the spectrum
had their development delayed. It is worthy of particular notice
that the rays which exert the greatest destroying power upon the
bacteria are the same as those which we have just stated were
most obnoxious to the ants — indeed, the same rays which most
powerfully affect the photographer's plate. This destroying action
of light is said to be a process of oxidation^ as the action is
increased when the supply of oxygen is increased, and diminished
when the oxygen is diminished. For instance. Anthrax bacilli
which were exposed to the direct rays of the sun in the presence
of air, were killed in two and a-half hours ; whereas Anthrax

THE INFLUENCE OF LIGHT ON LIFE. 251

bacilli which were exposed to the sun in vacuum were still alive
after fifty hours' exposure.

A very striking experiment is quoted by Frankland in illustra-
tion of this power of the sun. A glass tray is filled with a jelly,
in which are mixed the germs of, say, Typhoid bacillus. On the
back of the tray is pasted a cover of black paper, out of which
has been cut the word " Typhoid." The glass tray is then exposed,
upside down, to the sun ; that is, so that the jelly will receive the
sun's rays only through the spaces where the letters have been cut
out. After being exposed to the sun for two or three hours, the
glass tray is put into a dark cupboard and kept at such a tempera-
ture as will permit of the germs in the jelly developing and multi-
plying. Now, it is manifest that, if the sun has killed the germs
in the places where it shone upon them through the cut-out letters,
no development will take place throughout the whole word
" typhoid," and it is also clear that the germs will grow in all the
other parts of the jelly which were screened from the sun by the
black paper. This, according to Frankland, is what takes place,
the word " typhoid " being quite free from bacterial growths, while
the other parts are thickly populated.

In addition to this killing, or bactericidal, power, as it is called,
it has been found that, if the exposure to the light is not sufficient
to destroy the microbes, it may greatly alter their character. For
instance, in the case of a microbe which produced red pigment,
the sun's influence changed its nature so as to prevent it from any
longer producing the red pigment ; and, further, Dr, Palermo, of
Naples, placed some cholera bacilli in the sunshine, and found
that when they had been sunned for three or four hours they were
perfectly harmless, and that the animals which were inoculated
with them suffered no harm. Indeed, it was discovered that
guinea pigs which had been inoculated with the sunned and there-
fore innocuous bacilli were rendered proof against the virulent or
unsunned bacilli, and thus acted as a vaccination. When the
bacilli were not ''sunned," they killed guinea pigs in eighteen
hours, as is usual.

Frankland says, in pointing out the fact that in the Thames
water the number of micro-organisms was often twenty times as
numerous in winter as in summer, that the presence or absence of

252 THE INFLUENCE OF LIGHT ON LIFE.

sunshine no doubt plays some part in producing that result, and
he relates how two German students proved, by examining the
water in a certain river from six o'clock in the evening till six
o'clock in the morning, that the numbers were increased enor-
mously during the dark hours of night, and that when the light
returned in the morning the numbers were reduced again. An
experiment is quoted which showed that in a certain small quan-
tity of water, where there were at the surface 2,100 bacteria, three
hours' sunshine reduced the number to only nine, whereas in dark-
ness a similar number increased to 3,103. The destroying influence
of light i2L\\'mg perpendicularly does not extend to much depth in
the water. The organisms at the bottom of the quantity just
referred to were scarcely lessened in numbers. They were, how-
ever, prevented from increasing.

It may just be fair to state that I tried the experiment of
" sunning " an infusion of hay to see if the Bacillus subtilis would
be destroyed or hindered in the development ; but I regret to say
that they appeared to develop more rapidly than some which were
kept in the dark. My trial was a failure, but it cannot be regarded
as proving anything, for I feel sure it was not conducted properly.
The amount of hay in the tube would no doubt prove a sufficient
shelter for the organisms from the sun, and would therefore defeat
the very object in view. I might have tried the experiment again,
but was compelled to give it up in disgust, as the sun would not
shine when it was required to do so. When the experiment was
so far in train the sun would suddenly disappear for, perhaps, a
couple of days, and then reappear when it was too late. It is
satisfactory to note, however, that other gentlemen have had equal
troubles on this score, as they occasionally speak in a sort of
resigned tone of the advantages of experimenting under a more
favourable sky than we are blessed with. However, this does not
alter the wonderful results which have been found to follow inso-
lation (that is, exposure to the sun's rays), and it certainly ought to
move us to consider the possibilities which may be within our
reach when our knowledge of the subject is further advanced, and
to regard the sun as a benefactor whose bounty can scarcely be
fully appreciated.

No doubt the purity of the air, and to a certain extent also of

THE INFLUENCE OF LIGHT ON LIFE. 253

the water, is due to this marvellous power of light, for from what
we have just seen it seems reasonable to conclude that the sun is
continually destroying the germs of disease which exist around us.
No doubt the " sun bath," which I have been told is sometimes
resorted to in diseases of the lungs, is found advantageous for such
reasons as have just been given. It would be interesting to com-
pare the state of health of a community during a season of dull
and rainy weather with the state during a time of sunshine, as,
other things being equal, we might well expect to find our conclu-
sions as to the sun's beneficial influence confirmed by such a
comparison.

An effort has been made in this paper to confine our attention
to the action of light as it directly influences the vegetable and
animal world, and to avoid an extension of the subject to the
influence of light upon other phenomena in the world of Nature.
Although its influence upon other forces and matters is of great
importance in an indirect manner in affecting plant and animal
life, still our subject is sufficiendy complete in itself without refer-
ring to them here ; at any rate, it is sufficiently large for one
evening's consideration. We have gleaned the various particulars
here given from many writers, as well as from common observa-
tion, and have taken some pains to confirm, from as reliable
sources as possible, the different experiments and results which
have been quoted.

We have seen that almost the whole vegetable kingdom
requires, as absolutely necessary to existence, a sufficient supply
of light ; that animals are largely dependent, in a direct manner,
upon the same subtle influence, if, indeed, not also as dependent
upon it as plants; that man's physical and mental parts rebel
against the loss or absence of light, and are influenced in various
ways by its alteration ; and that the germs of disease which might
multiply beyond all knowledge are kept in check and subjugated
by the same friendly power.

When we focus all these facts to a point, we feel inclined to
repeat the dying words of Goethe and ask for " more light," and
we are almost forced to recognise, in wide streets, large windows,
and plenty of sunshine and fresh air, a method or plan by which
Nature will help us most effectually to preserve a sound mind in a
sound body.

254 PREDACIOUS AND PARASITIC

As we glance backwards, we see clearly that everything seems
to point definitely in the same direction, and to assert most posi-
tively that it is light which strews the earth with life in its myriad
forms ; that it is light which sustains and regulates the various
processes and phenomena of the vegetable kingdom, and also,
indirectly if not directly, of the animal kingdom ; that it is the
alteration of the quality or quantity of light which ushers in a
crowd of evil conditions ; and finally that it is the entire absence
of light which forbids the existence of life, and turns a garden of
paradise into a wilderness of death.

lpre&aciou6 & paraeitic Enemiee of Hpbibee

(incluMna a Stut)^ of 1b)?per^lParasites),

By H. C. a. Vine. Plates XII. & XIII.

DIFFERING widely in almost every detail of form and
structure from the Aphidivorous Insects which have been
considered in the previous sections, some of the Neurop-
TERA resemble them in their carnivorous habits^ the chief nutri-
ment of the larvae of three famiHes at least consisting of the juices
of Aphides, which, pierced by their tremendous mandibles, are
almost immediately reduced to an empty skin. Insect for insect,
these larvae are probably greater destroyers of Aphides than any
of the Syrphidae or the Coccinellidae, although the comparative
rarity with which they occur no doubt renders their aggregate
effect much less than that of either of the latter families.

Out of the many thousand species of insects indigenous in
Britain, not more than seven hundred are claimed for this very
beautiful order, even by those naturalists who include within it
some of the following groups : — Mallophaga (Bird lice), Thripidce
(Thrips, Black fly), Thysa?iura (Bristle-tails), Colletnbola (Spring-
tails), and Trichoptera (Caddis flies) ; all of which, by difl"erent
hands, have been placed in other orders. Apart from these, less
than three hundred and fifty species of the Neuroptera can
be said with certainty to be natives of Britain, and many of them
are very rarely met with.

ENEMIES OF APHIDES. 255

Proposals have been made from time to time for the removal
of the most typical families of this order, as originally constituted,
to the Orthoptera ; and since the time of Erichson they have been
so described by many naturalists, probably without taking due
account of their anatomy and development, under the designation
of " Pseudo-neuroptera." I shall hope, in a later part of this
section, to examine the anatomy, and possibly the embryology, of
one or two genera, with a view to the question of classification.
Independently of this proposed change, sections of the Neuroptera
have been bandied about by different writers to and from the
Orthoptera and the Diptera, while Professor Westwood declined
even to admit bird-lice and spring-tails among the Ifisecta. At
present the Neuroptera, as arranged by Kirby and other leading
Entomologists, includes fifteen families or sub-families. Some
writers recognise only a lesser number, and Miss Omerod, who
classes it in eleven families, truly says in her " Injurious Insects "
that there is among them scarcely a leading characteristic which
does not meet with an exception.

The Order is of Linnean origin, and Fabricius, the pupil of
the great Swede, in attempting to produce a classification which
should rival that of his master, constituted in the section Odoiiata,
containing the dragon flies, a division which has been generally
accepted by those who retain these species among the Neuroptera.
The other principal division, the Neuroptera Flanipen7iia, includes
the family of Hemerobiince, among which the aphidivorous species
of this order are to be found, the majority of the larvae of this
section being carnivorous. The various divisions of this interest-
ing and beautiful order, including all those families which are
commonly placed with it, comprise, throughout the world, about
four thousand species, but only a very limited number find a home
within the seas of Britain. A notable feature in the order, which
has occasioned much difference of opinion as to the true place of
many species of the section Odo7iata, is the imperfect nature of
their metamorphosis. In both families of Aphis-eating insects which
have been examined in these pages, the series of transformations
undergone has been that known as " perfect metamorphosis," in
which an active larva has been succeeded by an inert pupa,
which, in turn, produces a perfect winged form.

256 PREDACIOUS AND PARASITIC

But among the Neuroptera, in many species, the larvoe of which
live an aquatic life, the pupal form is characterised by an equal
amount of activity, and the imago emerges from the pupa still
enveloped in a delicate casing, which is thrown off after a short
interval. Other deviations from the normal metamorphosis also
occur, and will be of interest when, later on, we examine the
classification and internal anatomy, though, at present, we are only
concerned with the habits and characters of those species which
are Aphis-eaters, and among these the transformations are fairly
normal.

The elegance and brilliancy, the ferocity and strength of wing
which distinguish some members of this order have always ren-
dered them attractive objects to those who take an interest, even
in a casual way, in the observation of nature.

Mr. R. Maclachlan, writing in the pages of the Ento. Transac-
iiojis^ in 1868, in those valuable monographs which are the
standard authority on the Ahuroptera, says of them : — "The larvae
of these delicate insects play a great part in the economy of
nature, and must be considered as benefactors of the human race
in no'small degree. With those of Cocciiiella and Syrphus they
help to counteract the extraordinary fecundity of the Aphides, and
although their numbers are seldom so great as those of the Cocci-
iiella^ yet, from their activity and from the short time they take to
extract the juices of their prey, they must destroy innumerable
multitudes of these pests of the horticulturist." In another place
he refers to the well-established habit of some of these insects to
feign death when in peril. " Most of these insects fall down on
one side and feign death when disturbed, the legs being then
doubled up, the head drawn under the thorax, and the antennae
concealed."

In the early mornings of hot summer days and late in the
afternoons, and even sometimes in the heat of the day, the great
Dragon Fly {Libellula) or the elegant and slender Demoiselle
{Calypteryx or Agrion) may often be found in the neighbourhood
of sheltered streams, and occasionally in open pastures or about
roadside hedges, in rapid flight after some insect, by the capture
of which they will satisfy their carnivorous instincts. Among the
weeds of the neighbouring streams, the larvae follow an aquatic

ENEMIES OF APHIDES. 257

existence, destroying and making an increasing war upon the
other denizens of the water whom they are sufficiently powerful to
overcome.

But while in the more open spaces the quick movements and
untiring flight of these striking flies attract the eye, a more beau-
tiful variety of the same order, of heavier flight and less metallic,
though more elegant colouring, will often be seen beneath an over-
hanging oak or an aged elder, fluttering clumsily from bough to
bough, and sometimes leaving upon the leaves or stems where it
has pitched a white spot resembling a speck of mildew. The
insect belongs to the sub-family of Chrysopida, which, with the
Heiiierobiidce anc^ ConiopterygidcE^ constitute the family Heinero-
biincE, the larvae of which are Aphis eaters.

The larger of these flies, and especially the Chrysopidce, are
known popularly as "lace-wing flies," from the gauzy and peculi-
arly web-like texture of their ample wings, and sometimes as
" golden eyes," from the metallic, brassy appearance of their very
prominent eyes. The exquisite grass tint general in this sub-family
which pervades even the nervures of the delicate wings, prevents
their being readily detected, except when in actual flight, but the
presence of the female may often be judged by the white
spots already mentioned upon the leaves, or by a line of small
white excrescences upon some adjacent twig, such spots, in
truth, being but groups of the curious pedunculated eggs which
have attracted the attention of many generations of naturalists.
The female fly of C/uysopa perla, the species which being most
common in Britain is most conveniently studied, when about to
oviposit, touches with the extremity of her abdomen the surface
of a suitable leaf, leaving thereon a minute speck of glutinous
substance secreted by special glands, subservient to the organs of
reproduction. She next lifts her body, and from the leaf to the
ovipositor there stands a tiny white pillar of whalebone-like flexi-
bility, to the extremity of which an egg, escaping from the
ovipositor, seems to attach itself and remains erect, the patient
insect re-commencing its task and continuing until about ten or a
dozen eggs are similarly placed. Such a group is shown on Plate
XII. at Fig. I, where may be observed the curious precaution
taken by the fly lest the foundation of her supports should be

258 PREDACIOUS AND PARASITIC

insecure. In some instances, it would seem, one point of attach-
ment does not suffice, and the egg-carrying shaft is supported upon
two oblique buttresses of the same material. Sometimes, perhaps,
the surface of the leaf is unsuitable at the point which the fly has
selected, and then two or four buttresses yoked together afford the
necessary base for the attachment of the stem, and occasionally
such a foundation bears two or more stems, with their attached
eggs.

Dr. Fitch, in his report on Noxious and Beneficial Insects^ thus
describes the process of oviposition : — " Nature has furnished
these insects with a fluid analogous to that which spiders are pro-
vided with for spinning their webs, which possesses the remarkable
property of hardening immediately on being exposed to the air.
When ready to drop an egg, the female touches the surface of the
leaf with the end of her body, and then elevating the latter, draws
out a slender, thread-like cobweb, half an inch long or less, and
places a little oval egg at its summit. Thus, a small round
spot resembling mildew is formed upon the surface of the leaf,
from the middle of which arises a very slender, glossy, white thread,
which is sometimes split at its base, thus giving it a more secure
attachment than it would have if single."

The interesting and beautiful nature of this arrangement,
which produces the effect when seen under a low magnifying
power of a bunch of seed pearls, each mounted upon a thread,
has led to the expenditure of much ingenuity in the endeavour to
account for so peculiar a mode of oviposition. It is the generally
accepted view that it has arisen from the necessity of protecting
the eggs against the voracity of their own kind; but I am inclined
to think, from my own observation, that various other insects are
equally likely to be the agents of destruction, especially as the
larva of Chrysopa perla is sufficiently strong to attack and devour
Aphides larger than itself three or four hours after its emergence
from the egg, and therefore could have little need to become an
egg-eater, unless in the scarcity or absence of its usual food.

I have observed in several instances the larvae of Coccinella
bipunctata eat the eggs of its own kind, and the small Myifia larva
is known to destroy the eggs of many insects. Dr. Fitch has
shown in his Report on Noxious and Beneficial Insects, already

ENEMIES OF APHIDES. 259

quoted, that when first hatched the larvae of Chrysopidce live often
on the eggs of other insects, an observation which is confirmed by
a writer in Sciefice Gossip for the year 1890 — Mr. T. W. Wonfor,
of Brighton— who says that in the July of that year he saw a larva
of the Lacewing fly feeding on the eggs and young larvae of the
Dot Moth {Manesira persicaricp). It is, therefore, pretty certain
that while the young larvae of several insects which may frequent
the haunts of Chrysopa are egg-eaters, nothing has been observed
to show that the larvae of the latter destroy the eggs of their own
species. It seems not improbable that the frequency with which
Chrysopa is met with in comparison wnth the other Hemerobiince
may be due to the preservation of the eggs by the peculiar mode
of oviposition described.

If we adopt the classification of Dr. Hagen, we find that out
of thirty-two species of Henierobiidce which he describes, no less
than fifteen are placed under Chrysopa, whilst Hemerobius claims
seven only, and the remaining ten species are divided among five
genera.

Reaumur (Memoires sur les Insectes, Tom. III., PI. 32, 33)
gives four illustrations, apparently of various larvae of the Hemero-
biincB, but the want of detail renders it impossible to say to what
genus they belong except one, which is no doubt C perla. He
has, with the exercise of a fanciful imagination, often found in the
naturalists who laid the basis of our present knowledge, called these
curious larvae ' Aphis lions,' on account of some resemblance in
carrtivorous habit to the Myrmeleones, or 'Ant-lions,' and, indeed,
they are at least as formidable to the delicate aphis as the latter
are to their especial prey. They differ, however, in this : that
whereas the Ant-lion, having digged a pit, waits for the victim to
come to him, the 'Aphis lion,' on the contrary, exhibits usually a
remarkable activity in seeking its prey, and in case of scarcity of
food not hesitating occasionally to attack a larva of its own kind.
The struggles arising when two larvae happen to seize the same
aphis simultaneously are of a violent and often very ludicrous
character.

The larvae of Chrysopa and Hemerobius (which are practically
the only aphis-eating genera commonly met with) are long and
narrow in body, depressed, segments well marked and successively

260 PREDACIOUS AND PARASITIC

decreasing in size towards the tail, the last segments, however,
sometimes widening out slightly, so that the larva presents a slight
resemblance in shape to a fish. The head is proportioned to the
body, but small rather than large, and armed with a pair of formid-
able mandibles, as seen in PI. XIII., Fig. i. No good description
has been given of the mouth-organs, Reaumur's statement that the
mandibles are tubular being erroneous. The labial palpi are long,
porrected, and three jointed. The antennae are long, and present
the tapering appearance of a whip-lash. On examination with a
fairly high power, the scaly structure of the epidermis is readily
seen, as shown in PI. XIII., Fig. i, and the extremity, which
appears to consist of two delicate joints, terminates in a fine
bristle.

The eye will quickly attract attention by its peculiar arrange-
ment of several ocelli, grouped in slight protrusions on either side
of the head, and giving not the slightest indication of the extraor-
dinary development which the corresponding organs assume in the
perfect insect. Situated distinctly behind the lenses may be seen
the mass of pigment cells, which, being dark, is obvious even
through the egg-shell before the larva is hatched. The peculiari-
ties of the eye can be' observed by reference to Fig. 8, PL XIII.

The mandibles, which are deeply grooved on their inner sur-
faces to form channels within which the hollow maxillae play freely,
bear at each extremity a curious pad, which is depicted at Fig. 7
of the same plate, and which is surmounted by a stiff fine bristle,
the presence of which explains in some degree why an aphis, once
touched by the mandibles, rarely escapes.

About ten days after oviposition, in favourable weather, the
eggs, which at first have a very delicate greenish hue, become
slightly opaque, and then darken, and in a few hours the marking
of the segments and the pigment of the eye become visible
through the thin shell, as shown at Fig. 2, PI. XII. A slight
observation shows that, unlike some other families, the head
remains in close proximity to the microphyle, the posterior end of
the embryo being turned up so that the entire shape is somewhat
that of a flattened C- ^i^ examination of the contents of the egg
at this stage reveals the fact that the embryo is developed around,
as it were, the yolk, which is embraced by the anterior and poste-

ENEMIES OF APHIDES. 261

rior extremities. At this time the limbs are well developed, and
the reddish colour of the young larva is distinctly visible through
the shell.

The markings become more pronounced, and a few hours later
— usually in the early morning — the eggs split at their apices in a
direction parallel to their axis, and the larvae gradually twist them-
selves out. They frequently remain seated for a time on the top
of the empty eggs, and then creep away to hide themselves for a
short time under any neighbouring leaves, after which they com-
mence to attack any aphides that may be at hand. Occasion-
ally, as has been said, at this stage they will pierce and suck
out the contents of the eggs of any other insects which they
happen to meet with ; but it would seem that this generally
happens in the absence of a plentiful supply of x\phides, which
appear to be their most congenial food.

During the autumn of 1894, I bred from the eggs of Chrysopa
a number of larvae, which in due time pupated, and in this present
spring should produce the perfect flies. My notes of the progress
of one of the hatches may be of interest, and I transcribe them.

August j()th, i^g^. —ffemerobmicB. — Under an oak tree about
half-a-mile from Midsomer Norton Church, Somersetshire, I took
to-day a fine specimen of Chrysopa perla, which proved to be a
female which had or was about to oviposit. On examination of
the branch of the oak from which the fly emerged, I discovered a
group of nine stalked eggs recently laid, and the leaf with the
eggs was removed, and placed in a suitable breeding glass.

August 2^th. — These eggs, which were at first of a beautiful,
translucent green colour, when viewed with a magnifier, became now
white and opaque, and on careful examination showed a dark red-
brown spot near the upper end, and a series of somewhat rectan-
gular spots, in pairs, evidently indicating the segments of the
embryo, down one side.

August 2gt/i. — Four or five larvae hatched between six and
seven a.m.; length (extreme), as nearly as I could ascertain, i/ioth
of an inch. The eggs were each ruptured in the neighbourhood
of the microphyle, and more or less slit down the sides. The
colour of the young was greyish black. At i p.m. a larva, sepa-
rated in a glass box, attacked and ate a winged aphis (Ca//ipterus

262 PREDACIOUS AND PARASITIC

Quercus), a vast number of which were upon the oak whence the
eggs were taken. The body of the aphis was more than double
the size of the larva. It had great difficulty at first to secure a
hold, plunging its mandibles first into one portion and then into
another of the victim, as if not secure of a grasp, and when fairly
anchored by both mandibles it was several times lifted off the leaf
bodily by the struggles and superior weight of the aphis. The
larva, however, maintained its grasp, all the time sucking the
juices of the victim, and although unable to exhaust the latter so
completely as would be the case when fully grown, it left it in a
condition of complete collapse, the skin of the abdomen being
shrivelled and empty. During the afternoon other larvae were
hatched, making altogether nine from as many eggs. The eggs
are shown on Plate XII. at Figs, i and 2, and again at Fig. 3,
where the manner in which they are spHt open and the escape of
the larva is to be seen. At Fig. 4 is shown the larva above men-
tioned shortly after sucking the aphis, and details of the same
insect are given at Figs. 5, 6, 7, 8, and 9.

August 2,0th. — Length of larvae at 9 a.m., i/6th inch, several
aphides having disappeared. During the afternoon one attacked
a very large pea aphis, five times as heavy as itself The aphis,
seized behind the cornicles, struggled hard to get free, fixing its
legs and pulling. The larva also fixed its legs, apparently utilising
the suctorial power which enables it to ascend glass vertically, and
also attaching itself by the suction of the anal orifice at the poste-
rior extremity firmly to the surface on which it rested. Thus
anchored, it resisted all efforts of the huge aphis to drag itself
away, and retained its hold sufficiently to consume the greater part
of its victim, though several times, when the hold of the tail was
relaxed, lifted off its feet. The larvae are now all fairly active,
especially in the morning and evening, and after dark a match
suddenly struck reveals them running about the glass shade with
great rapidity. In middle day they frequently creep up the glass,
and remain underneath the thick glass at the top.

August ^ist. — Length, barely i/5th inch. The reddish colour-
ing of the segments is now very apparent.

September 27id. — Length, nearly i/4th inch — 11/48. The larvae
appear to feed chiefly at night. Pea, Oak, and Hazel Aphides
were all eaten indiscriminately.

ENEMIES OF APHIDES 263

Sepfe?nber ^th. — Length, i6/6oth of an inch,

September ^th. — Length, 6/2oth of an inch The bulk of the
insect increases much faster than the legs, which are now relatively
much smaller, and, after feeding the larvae, are now sometimes so
distended and heavy as to be unable to crawl any distance of the
vertical sides of the glass cover, and they fall from the height of an
inch or two, rolling over on their backs.

September ^th. — Length of larvae, i/srd of an inch. They
seem very sluggish and unable to move.

September loth. — Larvae have all cast their skins, emerging
from the discarded covering by a longitudinal slit in the dorsal
surface of the thoracic segments (I shall figure this cast skin in a
later section). Length now, 5/1 2th of an inch. Colours much
brighter. The black colouring of the extremities of the limbs is
due to the cast skin in which it is still encased is evident, the
fresh skin of the larva being clear.

September i^th. — Larvae, a bare 5/8th inch long. Now very
voracious, and of a flatter, broader shape than before. They now
eat thirty or forty Aphides apiece during the night, and appear
much distended. They make no attempt to ascend the glass, and
appear never to feed in the daytime, unless deprived of food at
night. When fully fed they are very thick, but in a few hours ^
become flat, like a flat-fish in shape.

September 22nd. — The larvae to-day became pupae, having
attained a length of over 5/8ths of an inch. The legs are now very
small in proportion to the body, which has become very broad.

The pupae are enveloped in a dense ball of fine silk, nearly
spherical in form and attached to the under surfaces of the leaves.
The cocoon is less in diameter than the length of the larva, and
the pupa is completely hidden within, a contrast to some of the
Hemerobiidce, which are so slightly covered as to leave the pupa
visible. The respective pupae are shown on Plate XIII., at
Figs. 9, ga, and 10, 10a, where the difference in appearance is
well displayed.

Some species of Hemerobiidce have a curious habit of covering
themselves partially with the skins of the exhausted Aphides, which,
by a peculiar jerking action of the head, they throw backwards, to
find a lodgment among the strong bristles of the back and sides.

264 PREDACIOUS AND PARASITIC

Such a larva is shown at Fig. 8 on Plate XIII., and, in its natural
situation on a stem or leaf, it often exhibits so little of the appear-
ance of an insect as to be taken, until a movement betrays it, for
a patch of dry lichen. Probably this habit may assist in protect-
ing it against the sharp eyes of birds.

In some species of this sub-family the larvae are small and more
delicate in structure, rarely attaining to 5/i2ths of an inch in
length, and from their subdued grey colouring are much less
readily seen and captured than those previously described. They
are of exceeding quickness of movement, and complete their
larval existence in a shorter term than the young of the Chrysopi-
dcB. The pupa is but slightly covered with silk in those genera
which I have been able to observe, and the fly is as remarkable
for the dulness and soberness of its tints as that of the previously
described group is for its brilliancy. The wings of the Hemero-
biidce are generally thickly fringed with sparse, distinct hairs,
which arise also at the junction of the nervures of the wings.
The cross nervures of the latter are much fewer than in the
Chrysopidce^ and constitute an important differential character.

The larva of Hemerobiidce is shown on Plate XIII. at P'ig. 3,
and the pupa at 9 and 9^. Fig. 4 shows the perfect insect which
emerged from the pupa, 9^. The disproportion between the size
of the pupa and the imago is not so marked in this sub-family as
in the ChrysopidcB, although even here it seems impossible that
the delicate wings should be contained in so small a space as that
occupied by the pupa.

The most plentiful species of Hemerobiidce, so far as I am
aware, appears to be the H. humuhis^ which is found in great
numbers in hop gardens, where it performs an essential service to
man by the rapidity with which it destroys the fly — aphis humuli —
one of the great enemies of the hop-grower, and which is with
difficulty kept in check by artificial means. Some species, such as
that figured, frequent in the larval state fine grass, while others
may not uncommonly be taken beneath the leaves of the oak, on
the elder, and on the dog rose.

Besides Hemerobiiis, two other genera of the sub-family are
believed to be aphidivorous : Drepanopteryx, a genus which con-
sists of one species only ; D. Fhalcenoides (Linn.), which is

ENEMIES OF APHIDES. 265

very rare, a few specimens only having been taken in the north of
England and the southern counties of Scotland. It is very similar
to Hemerobius, and is said by Dr. Hagen and other writers to be
aphidivorous, but there appears to have been but little accurate
observation made of its larval habits and development.

The remaining genus, to the larvae of which the aphis-eating
habit is attributed, is Micromus. The young resemble those of
Hemerobius, and are said by Mr. MacLachlan to be " probably
aphidivorous," but until opportunity occurs for a more perfect
examination of their hfe-history, it is scarcely safe to assume so
much for a certainty. As yet, I have failed to obtain either egg or
a living specimen of the larva.

In the typical genus of this group of aphis eaters, Hemerobius,
the species are, among other features, characterised, as regards the
males, by remarkable modifications of the extremity of the abdo-
men. These are of great interest for purposes of classification,
and in a later number will be figured, when the arrangement of
the families and genera is reviewed. Unfortunately, nothing like
corresponding diff'erences in structure are visible in the female
lace-wings j hence, their value for ordinary working purposes is
comparatively little.

At the lower part of PI. XIII. will be seen at Fig. 6 a peculiar
looking insect, the appearance of which would scarcely lead to the
supposition that it was a Neuropterous larva. The drawing is
taken from Curtis's British Eiitotnology , and represents the larva of
the curious little ' lace-wing,' Coniopteryx tineiformis, a fairly typi-
cal species of the Coniopterygidce. The fly is frequently to be
found in summer on fir trees, in plantations and woods, in com
pany with the various aphides that feed on them ; but it is difficult
to detect, or at any rate to secure, the larva. Its aphidivorous
habits are, however, well established, and for its size there is no
reason to doubt that its destructive powers equal those of the
larger genera. The larva spin an oval cocoon of densely woven
silk, which entirely conceals the pupa formed within it ; and
although in the earlier generations of the year the escape of the
imago is not long delayed, the pupae of the autumn larvae retain
their condition until the following spring, when the continuance of
sunshine quickly causes the appearance of the imago.

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. t

266 PREDACIOUS AND PARASITIC

The fly is small and does not readily attract attention ; indeed,
it may easily be taken as it is found among a group of Aphides, for
some large species of that family, a resemblance which is
increased by the dusting of the body with a white mealy powder.
Once noticed, however, this character — combined with their pecu-
liar neuropterous wing venation and shape and the thread-like
antennae — make their identification easy. The front wings are
more irregular in shape than in the families already mentioned
(which approach the typical form), and are almost destitute of the
transverse veins which form so striking a feature in Chrysopa and
Hemerobius. The longitudinal veins, however, represent very
nearly the chief lines of venation in the former, as will be seen
when the drawing, now given, of the wings of Coniopteryx is com-
pared with an enlarged drawing of the wing of Chrysopa, which
will be given in the next part. By a comparison of these it seems
almost possible to see how the single longitudinal veins of the
humbler, although no doubt the more ancient family have given
rise to the elegant network which fixes our admiration in the deli-
cate ' Lacewing/ in which, as we shall see hereafter, the firm veins
of the former have given place to the fragile vascular structure
which supports the latter, and which is provided with a system of
circulation of a most marvellous character.

The posterior wings of Coniopteryx differ far more from the
front wings, both in size and shape, than is the case with other
aphis-eating species, but the venation, so far as it persists, follows
the same plan as in the front wings. The shape of the hinder
wings, with their often narrowed extremities, approaches somewhat
that of the same structures in some species of the Hymenoptera.
The peculiar character of the venation possesses special interest
for the student of the development of species, as its comparatively
rudimentary structure suggests the possibility of a survival of the
details of an early stage in the growth of the neuropterous group.

These insects were observed by Westwood to differ from the
typical species Hemerobius, in the slight reticulation of the wings,
the slight mealy covering without any appearance of cilia upon the
wings, the large size of the terminal joint of labial palpi, obsolete
ligula, absence of tibial spurs, and smaller size of posterior wings.
In common with other of the HemerobiincB they sit with wings

Journal of Microscopy N.S. Vol.5. Plate 12.

H.C.A\^rv&3xjl:na.tdel.

F.Phil/lps.Sc.

lUustratcons of Apkulivoroics Nemerobunae.

Journal of Microscopy N.S. Vol. 5. Plate 13.

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fllicstraUons of Aphidivorous RemejvdiiT'ZCce.

ENEMIES OF APHIDES. 267

deflexed, and when threatened feign death by bending the anten-
nae under the body.

The sub-family consists of but the single genus Coniopteryx,
which comprises three species only, as given by Maclachlan.

DESCRIPTION OF PLATES XII. and XIII.

n

>?

Plate XII.

Illustrations of Aphidivorous Larvae of the Neuroptera Planipennia,

fam. Hemerohiinre.

Fig. 1. — A group of nine stalked eggs on oak leaf. Taken shortly
after laying by the lace-wing fly (Chrysopa perla) (3-in. objec-
tive).

,, 2. — One of the eggs the day prior to hatching (twelve days after
oviposition), showing young larva within (1-in. objective).

3. — Same eggs as Fig. 1, showing larvae escaping and the empty
eggs, split lo7igitudinally.

4. — Larva at four or five hours after hatching. At this age it is
fairly transparent, very active, and will readily attack aphides

5. — One of the long palpi of head ( ? maxillary palpi), showing a
structure resembling that of the antennae of Aphis, and ter-
minated by a long fine bristle.

6. — Mandible, showing hollow channel and the maxilla within,
which works up and down in the groove. The latter is seen to
contain food.

,, 7. — Extremity of mandible, showing the minute cushion with
^exceedingly fine spines, by w^hich it is terminated ; also, the
long thin bristle at apex, and within, the extremity of the
- sucking maxilla.

,, 8. — The eye, seen sideways. The eye in the larva consists of^
several ocelli, grouped together.

,, 9. — The claw and appendages, showing at the extremity of the
tarsus the double hooks with strong bristles, and extending
between them the slender tendinous process, carrying at its
extremity the suctorial (?) pad, which has in its cup-shaped
hollow several minute teat-like organs, which are probably the
outlets of glands, yielding some secretion which lubricates
the pad.

Plate XIIL

Fig. 1. — Larva of Chrysopa perla, nearly full grown, with an aphis in
its mandibles.

))

2. — Imago of same (female).

>J

)5

268 ENEMIES OF APHIDES.

Fig. 3. — Larva of HemerohinSy full grown. The proportion to the larva
in Fig. 1 is nearly correct. The larv?e of many species are
very minute.

4. — Imago bred from larva. The difference in wing venation and
the hairs on the wings may be observed.

5. — Oak stem, bearing a number of stalked eggs of Chrysopa,
placed in a consecutive line on the stem, as is sometimes found.

6. — Larva of Coniopteryx tineiformis, after Curtis.

7. — Wing venation of the imago of C. tineiformis, showing the
smaller hind wing and absence of transverse veins.

8. — Larva of Hemerohius, laden with the empty skins of slain
Aphides ; likened by Reaumur to Hercules elothed in the
skin of the Nemean lion.

9, 9a. — The cocoon and pupa of Hemerobius, showing the slight
nature of the silk threads sparsely arranged round the pupa
to form the cocoon.

,, 10, 10a. — The cocoon of Chrysopa perla. The pupa is quite hidden
by the dense silk-like texture of the cocoon, Avhich is thick
and nearly spherical.

>?

5?

How THE Musk-Rat Breathes under Ice. — Animals that
breathe by means of lungs can prolong their stay underjwater only
through special anatomical arrangements, or by having recourse to
some extraneous means. Mr. W. Spoon, of the Elisha Mitchell
Society, who has hunted the musk-rat in winter, asserts that the
animal, when obliged to traverse, under ice, a pond so wide that
it cannot keep up its breathing, stops from time to time and
exhales the air from its lungs. This air, being confined by the ice,
becomes oxygenated in contact with the water, and the animal,
taking a fresh inspiration, dives in order to begin its swimming
again a little further along. It appears that other observers have
found that if this air is dispersed through the ice being struck the
animal is killed through asphyxia.

[ 269 ]

Zbc ©rigin of the ©l&eet 3fo6eil6 an^ tbe
Discoveri? of tbe :S5ottom of tbe ©cean,*

By W. K. Brooks.

IN the Origin of Species^ Darwin says that the sudden appear-
ance of species belonging to several of the main divisions
of the animal kingdom in the lowest known fossiliferous
rocks is at present inexplicable, and may be truly urged as a valid
objection to his views.

If his theory be true, he says that "it is indisputable that before
the lowest Cambrian stratum was deposited long periods elapsed,
as long as, or probably far longer than the whole interval from the
Cambrian age to the present day ; and that during these vast
periods the world swarmed with living creatures. Here," he
says, "we encounter a formidable objection; for it seems doubtful
whether the earth, in a fit state for the habitation of living crea-
tures, has lasted long enough." "To the question why we do
not find such fossiliferous deposits belonging to these assumed
earliest periods prior to the Cambrian system I can give no satis-
factory answer."

On its geological side this difficulty is even greater than it was
in Darwin's day, for we now know that the fauna of the lower
Cambrian was rich and varied ; that most of the modern types of
animal life were represented in the oldest fauna which has been
discovered, and that all its types have modern representatives.
The palaeontological side of the subject has been ably summed up
by Walcott in an interesting memoir on the oldest fauna which is
known to us from fossils, and his collection of 141 American
species from the lower Cambrian is distributed over most of the
marine groups of the animal kingdom, and, except for the absence
of the remains of vertebrated animals, the whole province of
animal life is almost as completely covered by these 141 species
as it could be by a collection from the bottom of the modern
ocean. Four of the American species are sponges, two are
hydrozoa, nine are actinozoa, twenty-nine are brachiopods, three
are lamellibranchs, thirteen are gasteropods, fifteen are pteropods,

* A paper read before the University Scientific Association, and printed
in the Journal of Geology^ Chicago, 1894.

270 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

eight are Crustacea, fifty-one are trilobites, and trails and burrows
show the existence of at least six species of bottom forms, pro-
bably worms or Crustacea. The most notable characteristic of
this fauna is the completeness with which these few species outline
the whole fauna of the modern sea floor. Far from showing us
the simple unspecialised ancestors of modern animals, they are
most intensely modern themselves in the zoological sense, and
they belong to the same order of nature as that which prevails
at the present day.

The fossiHferous beds of the lower Cambrian rest upon beds
which are miles in vertical thickness, and are identical in all their
physical features with those which contain this fauna. They prove
beyond question that the waters in which they were laid down
were as fit for supporting life at the beginning as at the end of the
enormous lapse of time which they represent, and that all the
conditions have since been equally favourable for the preservation
and the discovery of fossils. Modern discovery has brought the
difficulty which Darwin points out into clearer view, but geologists
are no more prepared than he was to give a satisfactory solution,
although I shall now try to show that the study of living animals
in their relations to the world around them does help us, and that
comparative anatomy and comparative embryology and the study
of the habits and affinities of organisms tell us of times more
ancient than the oldest fossils, and give a more perfect record of
the early history of Hfe than palaeontology.

While the history of life, as told by fossils, has been slow and
gradual, it has not been uniform, for we have evidence of the
occurrence of several periods when modification was comparatively
rapid.

We are living in a period of intellectual progress, and, among
terrestrial animals, cunning now counts for more than size or
strength, and fossils show that while the average size of mammals
has diminished since the middle tertiary, the size of their brains
has increased more than one hundred per cent. ; that the brain of
a modern mammal is more than twice as large, compared with its
body, as the brain of its ancestors in the middle tertiary. Mea-
sured in years, the middle tertiary is very remote, but it is very
modern compared with the whole history of the fossiUferous rocks.

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 271

although more of brain development has been effected in this short
time than in all preceding time from the beginning.

The later palaeozoic and early secondary fossils mark another
period of rapid change, when the fitness of the land for animal
life, and the presence of land plants, brought about the evolution
of terrestrial animals.

I shall give reasons for seeing, in the lower Cambrian, another
period of rapid change, when a new factor, the discovery of the
bottom of the ocean, began to act in the modification of species,
and I shall try to show that, while animal life was abundant long
before, the evolution of animals likely to be preserved as fossils
took place with comparative rapidity, and that the zoological fea-
tures of the lower Cambrian are of such a character as to indicate
that it is a decided and unmistakable approximation to the primi-
tive fauna of the bottom, beyond which life was represented only
by minute and simple surface animals not likely to be preserved
as fossils.

Nothing brings home more vividly to the zoologist a picture
of the diversity of the lower Cambrian fauna, and of its intimate
relation to the fauna on the bottom of the modern ocean, than
the thought that he would have found on the old Cambrian shore
the same opportunity to study the embryology and anatomy of
pteropods and gasteropods and lamellibranchs, of Crustacea and
medusae, echinoderms and brachiopods that he now has at a
marine laboratory ; that his studies would have followed the same
lines then that they do now, and that most of the record of the
past which they make known to him would have been ancient
history then. Most of the great types of animal life show by their
embryology that they run back to simple and minute ancestors
which lived at the surface of the ocean, and that the common
meeting point must be projected back to a still, more remote time,
before these ancestors had become differentiated from each other.

After we have traced each great line of modern animals as far
backwards as we can through the study of fossils, we still find
these lines distinctly laid down. The lower Cambrian Crustacea,
for example, are as distinct from the lower Cambrian echinoderms
or pteropods or lamellibranchs or brachiopods as they are from
these of the present day, but zoology gives us evidence that the

272 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

early steps in the establishment of these great lines were taken
under conditions which were very different from those which have
prevailed, without any essential change, from the time of the oldest
fossils to the present day, and that most of the great lines of
descent were represented in the remote past by ancestors which,
living a different sort of life, differed essentially, in structure as
well as in habits, from the representatives of the same types w^hich
are known to us as fossils.

In the. echinoderms we have a well-defined type represented
by abundant fossils, very rich in living forms, very diversified in
its modification, and therefore well fitted for use as an illustration.
This great stem contains many classes and orders, all constructed
on the same plan, which is sharply isolated, and quite unlike the
plan of structure in any other group of animals. All through the
series of fossiUferous rocks echinoderms are found, and their plan
of structure is always the same. Palaeontology gives us most
valuable evidence regarding the course of evolution within the
limits of a class as in the crinoids or echinoids ; but we appeal to
it in vain for light upon the organisation of the primitive echino-
derm, or for connecting links between the classes. To our ques-
tions on these subjects, and on the relation of echinoderms to
other animals, palaeontology is silent, and throws them back upon
us as unsolved riddles.

The zoologist unhesitatingly projects his imagination, held in
check only by the laws of scientific thought, into the dark period
before the times of the oldest fossils, and he feels absolutely
certain of the past existence of a stem, from which the classes of
echinoderms have inherited the fundamental plan of their struc-
ture. He affirms with equal confidence that the structural changes
which have separated this ancient type from the classes which we
know from fossils, are very much more profound and extensive
than all the changes which each class has undergone from the
earliest palaeozoic times to the present day.

He is also disposed to assume, but, as I shall show, with much
less reason, that the amount of change which structure has under-
gone is an index to the length of time which the change has
required, and that the period which is covered by the fossiliferous
rocks is only an inconsiderable part of that which has been con-
sumed in the evolution of the echinoderms.

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 273

The zoologist does not check the flight of his scientific imagi-
nation here, however, for he trusts impHcitly to the embryological
evidence which teaches him that, still farther back in the past, all
echinoderms were represented by a minute floating animal which
was not an echinoderm at all in any sense, except the ancestral
one, although it was distinguished by features which natural selec-
tion has converted, under the influence of modern conditions, into
the structure of echinoderms. He finds in the embryology of
modern echinoderms phenomena which can bear no interpretation
but this, and he unhesitatingly assumes that they are an inheri-
tance which has been handed down from generation to generation
through all the ages from the prehistoric times of zoology.

Other groups tell the same story with equal clearness. Lingula
is still living in the sand bars and mud flats of the Chesapeake
Bay, under conditions which have not effected any essential change
in its structure since the time of the lower Cambrian. Who can
look at a living lingula without being overwhelmed by the effort to
grasp its immeasurable antiquity ; by the thought that while it has
passed through all the chances and changes of geological history,
the structure which fitted it for life on the earliest palaeozoic bottom
is still adapted for a life on the sands of the modern sea floor ?

The everlasting hills are the type of venerable antiquity ; but
lingula has seen the continents grow up, and has maintained its
integrity unmoved by the convulsions which have given the crust
of the earth its present form. As measured by the time-standards
of the zoologist, lingula itself is modern, for its life-history still
holds locked up in its embryology the record, repeated in the
development of each individual, of a structure and a habit of life,
which were lost in the unknown past at the time of the lower
Cambrian, and it tells us vaguely but unmistakably of life at
the surface of the primitive ocean, at a time when it was repre-
sented by minute and simple floating ancestors.

Broadly stated, the history of each great line has been like that
of the echinoderms and brachiopods. The oldest pteropod or
lamellibranch or echinoderm or crustacean or vertebrate which we
know from fossils exhibits its own type of structure with perfect
distinctness, and later influences have done no more than to ex-
pand and diversify the type, while anatomy fails to guide us back

274 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

to the point where these various Hnes met each other in a common
source, although it forces us to beheve that the common source
once had an individual existence. Embryology teaches that each
Ime once had its own representative at the surface of the ocean,
and that the early stages in its evolution have passed away and
left no record in the rocks.

If we try to call before the mind a picture of the land surface
of the earth we see a vast expanse of verdure, stretching from
high up in the mountains over hills, valleys, and plains, and through
forests and meadows down to the sea, with only an occasional lake
or broad river to break its uniformity.

Our picture of the ocean is an empty waste, stretching on and
on, with no break in the monotony except now and then a flying
fish or a wandering sea-bird or a floating tuft of sargassum, and
we never think of the ocean as the home of vegetable life. It
contains plant-like animals in abundance, but these are true ani-
mals and not plants, although they are so like them in form and
colour. At Nassau, in the Bahama Islands, the visitor is taken in
a small boat, with windows of plate-glass set in the bottom, to visit
the " sea gardens " at the inner end of a channel through which
the pure water from the open sea flows between two coral islands
into the lagoon. Here the true reef-corals grow in quiet water,
where they may be visited and examined.

When illuminated by the vertical sun of the tropics and by
the light which is reflected back from the white bottom, the pure
transparent water is as clear as air, and the smallest object forty or
fifty feet down is distinctly visible through the glass bottom of the
boat. As this glides over the great mushroom-shaped coral domes
which arch up from the depths, the dark grottoes betw-een them
and the caves under their overhanging tops are lighted up by the
sun, far down among the anthozoa or flow^er animals and the
zoophytes or animal plants, which are seen through the waving
thicket of brown and purple sea fans and sea feathers as they toss
before the swell from the open ocean.

There are miles of these " sea gardens " in the lagoons of the
Bahamas, and it has been my good fortune to spend many months
studying their wonders, but no description can convey any con-
ception of their beauty and luxuriance. The general effect is very

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 275

garden-like, and the beautiful fishes of black and golden yellow
and iridescent cobalt blue hover like birds among the thickets of
yellow and lilac gorgonias.

The parrot fishes seem to be cropping the plants like rabbits,
but more careful examination shows that they are biting off the
tips of the gorgonias and branching madrepores or hunting for the
small Crustacea which hide in the thicket, and that all the apparent
plants are really animals.

The delicate star-like flowers are the vermilion heads of boring
annelids or the scarlet tentacles of actinias, and the thicket is
made up of pale lavender bushes of branching madrepores, and
green and brown and yellow and olive masses of brain coral, of
alcyonarians of all shades of yellow and purple, lilac and red, and
of black and brown and red sponges. Even the lichens which
incrust the rocks are hydroid corals, and the whole sea garden is
a dense jungle of animals, where plant-life is represented only by
a few calcareous algae so strange in shape and texture that they
are much less plant-like than the true animals.

, The scarcity of plant-life becomes still more notable when we
study the ocean as a whole. On land herbivorous animals are
always much more abundant and prolific than the carnivora, as
they must be to keep up the supply of food, but the animal life of
the ocean shows a most remarkable difference, for marine animals
are almost exclusively carnivorous.

The birds of the ocean — the terns, gulls, petrels, divers, cormo-
rants, tropic birds, and albatrosses — are very numerous indeed,
and the only parallel to the pigeon roosts and rookeries of the land
is found in the dense clouds of sea birds around their breeding
grounds, but all these sea birds are carnivorous, and even the birds
of the seashore subsist almost exclusively upon animals, such as
moUusca, Crustacea, and annelids. The seals pursue and destroy
fishes ; the sea-elephants and walruses live upon molluscs ; the
whales, dolphins, and porpoises and the marine reptiles all feed
upon animals, and most of them are fierce beasts of prey. '

There are a few fishes which pasture in the fringe of seaweed
which grows on the shore of the ocean, and there are some which
browse among the floating tufts of algae upon its surface, but most
of them frequent these places in search of the small animals
which hide among the plants.

276 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

In the Chesapeake Bay the sheepshead browses among the
algae upon the submerged rocks and piles like a marine sheep, but
its food is exclusively animal, and I have lain upon the edge of a
wharf watching it crunch the barnacles and young oysters until the
juices of their bodies streamed out of the angles of its mouth,
and gathered a host of small fishes to snatch the fragments as they
drifted away with the tide.

Many important fishes, like the cod, pasture on the bottom, but
their pasturage consists of molluscs and annelids and Crustacea
instead of plants, and the vast majority of sea fishes are fierce
hunters, pursuing and destroying smaller fishes, and often exhibit-
ing an insatiable love of slaughter, like our own blue fish and the
tropical albacore and barracuda. Others, such as the herring, feed
upon smaller fishes and the pelagic pteropods and copepods ; and
others, like the shad, upon the minute organisms of the ocean ;
but all, with few exceptions, are carnivorous. In the other great
groups of marine animals we find some scavengers, some which
feed upon micro-organisms, and others which hunt and destroy
each other; but there is no group of marine animals which cor-
responds to the herbivora and rodents and the plant-eating birds
and insects of the land.

There is so much room in the vast spaces of the ocean, and so
much of it is hidden, that it is only when surface animals are
gathered together that the abundance of marine life becomes
visible and impressive ; but some faint conception of the boundless
wealth of the ocean may be gained by observing the quickness
with which marine animals become crowded together at the surface
in favourable weather. On a cruise of more than two weeks along
the edge of the gulf-stream, I was surrounded continually night
and day by a vast army of dark brown jelly-fish (Linerges mercutia),
whose dark colour made them very conspicuous in the clear water.
We could see them at a distance from the vessel, and at noon when
the sun was overhead we could look down to a great depth through
the centre-board well, and everywhere, to a depth of fifty or sixty
feet, we could see them drifting by in a steady procession, like
motes in a sunbeam. We cruised through them for more than five
hundred miles, and we tacked back and forth over a breadth of
almost a hundred miles, and found them everywhere in such

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 277

abundance that there were some in every bucketful of water which
we dipped up, nor is this abundance of life restricted to tropical
waters, for Haeckel tells us that he met with such enormous masses
of Lwiacina to the north west of Scotland, that each bucket of
water contained thousands.

The tendency to gather in crowds is not restricted to the
smaller animals, and many species of raptorial fishes are found in
densely packed banks.

The fishes in a school of mackerel are as numerous as the birds
in a flight of wild pigeons, and we are told of one school which
was a windrow of fish half a mile wide and at least twenty miles
long. But while pigeons are plant eaters, the mackerel are rapa-
cious hunters, pursuing and devouring the herrings as well as other
animals. Herring swarm like locusts, and a herring bank is almost
a solid wall. In 1879 three hundred thousand river herring were
landed in a single haul of the seine in Albemarle Sound ; but the
herring are also carnivorous, each one consuming myriads of
copepods every day.

In spite of this destruction and the ravages of armies of medusae
and siphonophores and pteropods, the fertility of the copepods is
so great that they are abundant in all parts of the ocean, and they
are met with in numbers which exceed our power of comprehen-
sion. On one occasion the Challenger steamed for two days
through a dense cloud formed of a single species, and they are
found in all latitudes from the Arctic regions to the equator in
masses which discolour the water for miles. We know, too, that
they are not restricted to the surface, and that the banks of cope-
pods are sometimes more than a mile thick. When we reflect that
thousands would find ample room and food in a pint of water, one
can form some faint conception of their universal abundance.

The organisms which are visible in the water of the ocean and
on the sea bottom are almost universally engaged in devouring
each other, and many of them, like the blue-fish, are never satis-
fied with slaughter, but kill for mere sport.

Insatiable rapacity must end in extermination unless there is
some unfailing supply, and as we find no visible supply in the
water of the ocean we must seek it with a microscope, which shows
us a wonderful fauna made up of innumerable larvae and embryos

278 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

and small animals, but these things cannot be the food-supply of
the ocean, for no carnivorous animal could subsist very long by
devouring its own children. The total amount of these animals is
inconsiderable, however, when compared with the abundance of a
few forms of protozoa and protophytes, and both observation and
deduction teach that the most important element in marine life
consists of some half-dozen types of protozoa and unicellular
plants ; of globigerina and radiolarians, and of trichodesmium,
pyrocystis, protococcus and the coccospheres, rhabdospheres, and
diatoms.

Modern microscopic research has shown that these simple
plants, and the globigerinae and radiolarians which feed upon them,
are so abundant and prolific, that they meet all demands and
supply the food for all the animals of the ocean. This is the fun-
damental conception of marine biology. The basis of all the life
in the modern ocean is found in the micro-organisms of the surface.

This is not all. The simplicity and abundance of the micro-
scopic forms and their importance in the economy of nature show
that the organic world has gradually taken shape around them as
its centre or starting-point, and has been controlled by them.
They are not only the fundamental food-supply but the primeval
supply, which has determined the whole course of the evolution
of marine life. The pelagic plant-life of the ocean has retained
its primitive simplicity on account of the very favourable character
of its environment, and the higher rank of the littoral vegetation
and that of the land is the result of hardship.

On land the mineral elements of plant-food are slowly supplied,
as the rains dissolve them; limited space brings crowding and com-
petition for this scanty supply ; growth is arrested for a great part
of each year by drought or cold ; the diversity of the earth's sur-
face demands diversity of structure and habit ; and the great size
and complicated structure of terrestrial plants are adaptations to
these conditions of hardship.

At the surface of the ocean the abundance and uniform distri-
bution of mineral food in solution ; the area which is available for
plants ; the volume of sunlight and the uniformity of the temper-
ature are all favourable to the growth of plants, and as each plant
is bathed on all sides by a nutritive fluid, it is advantageous for the

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 279

new plant-cells which are formed by cell-multiplication to separate
from each other as soon as possible, in order to expose the whole
of their surface to the water. Cell-aggregation, the first step
towards higher organisation, is therefore disadvantageous to the
pelagic plants, and as the environment at the surface of the ocean
is so monotonous, there is little opportunity for an aggregation of
cells to gain any compensating advantage by seizing upon a more
favourable habitat. The pelagic plants have retained their prim-
itive simplicity, and the most distinctive peculiarity of the micro-
scopic food-supply of the ocean is the very small number of forms
which make up the enormous mass of individuals.

All the animals of the ocean are dependent upon this supply
of microscopic food, and many of them are adapted for preying
upon it directly, but a review of the animal kingdom will show
that no highly organised animal has ever been evolved at the
surface of the ocean, although all depend upon the food-supply
of the surface.

The animals which now find their home in the open waters of
the ocean are, almost without exception, descendants of forms
which lived upon or near the bottom, or along the sea-shore, or
upon the land, and all the exceptions are simple animals of minute
size. A review of the whole animal kingdom would take more
space than we can spare, but it would show that the evidence from
embryology, from comparative anatomy and from palaeontology,
all bears in the same direction, and proves that every large and
highly organised animal in the open ocean is descended from
ancestors whose home was not open water but solid ground, either
on the bottom or on the shore.

Embryology also gives us good ground for believing that all
these animals are still more remotely descended from minute and
simple pelagic ancestors, and that the history of all the highly
organised inhabitants of the water has followed a roundabout path
from the surface to the bottom, and then back into the water.
When this fact is seen in all its bearings, and its full significance
is grasped, it is certainly one of the most notable and instructive
features of evolution.

The food-supply of marine animals consists of a few species
of microscopic organisms which are inexhaustible, and the only

280 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

source of food for all the inhabitants of the ocean. The supply
is primeval as well as inexhaustible, and all the life of the ocean
has gradually taken shape in direct dependence upon it. In view
of these facts, we cannot but be profoundly impressed by the
thought that all the highly organised marine animals are products
of the bottom or the shore or the land, and that while the largest
animals on earth are pelagic, the few which are primitively pelagic
are small and simple.

The reason is obvious. The conditions of life at the surface
are so easy that there is little fierce competition, and the inorganic
environment is so simple that there is little chance for diversity
of habits.

The growth of terrestrial plants is limited by the scarcity of
food, but there is no such limit to the growth of pelagic plants or
the animals which feed on them, and while the balance of life is
no doubt adjusted by competition for food this is never very fierce,
even at the present day, when the ocean swarms with highly orga-
nised wanderers from the bottom and the shore. Even now the
destruction or escape of a microscopic pelagic organism depends
upon the accidental proximity or remotenesses of an enemy rather
than upon defence or protection, and survival is determined by
space relations rather than a struggle for existence.

The abundance of food is shown by the ease with which wan-
derers from the land, like sea birds, find places for themselves in
the ocean, and the rapidity with which they spread over its
whole extent.

As a marine animal the insect, Halobates, must be very mod-
ern as compared with most pelagic forms, yet it has spread over
all tropical and sub-tropical seas, and it may always be found
skimming over the surface of mid-ocean as much at home as a
Gerris in a pond. I never found it absent in the Gulf Stream
when conditions were favourable for collecting.

The easy character of pelagic life is shown by the fact that
the larvse of innumerable animals from the bottom and the
shore have retained their pelagic habit, and I shall soon give
reasons for believing that the larva of a shore animal is safer
at sea than near the shore.

There was little opportunity in the primitive pelagic fauna and

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 281

flora for an organism to gain superiority by seizing upon an advan-
tageous site or by acquiring peculiar habits, for one place was like
another, and peculiar habits could count for little in comparison
with accidental space relations. After the fauna of the surface
had been enriched by all the marine animals which have become
secondarily adapted to pelagic life^ competition with those improved
forms brought about improvements in those which were strictly
pelagic in origin, like the siphonophores, and those wanderers
from the bottom introduced another factor into the evolution of
pelagic life, for their bodies have been utilised for protection or
concealment and in other ways, and we now have fishes which
hide in the poison curtain of Physalia, Crustacea which live in the
pharynx of Salpa or in the mouth of the menhaden, barnacles and
sucking fish fastened to whales and turtles, besides a host of exter-
nal and internal parasites. The primitive ocean furnished no such
opportunity, and the conditions of pelagic life must at first have
been very simple, and while competition was not entirely absent
the possibilities of evolution must have been extremely limited,
and the progress of divergent modification very slow, so long as
all life was restricted to the waters of the ocean.

There can be no doubt that floating life was abundant for a
long period when the bottom was uninhabited. The slow geological
changes by which the earth gradually assumed its present charac-
ter present a boundless field for speculation, but there can be no
doubt that the surface of the primeval ocean became fit for living
things long before the deeper waters or the sea floor, and during
this period the proper conditions for the production of large and
complicated organisms did not exist, and even after the total
amount of life had become very great it must have consisted of
organisms of small size and simple structure.

Marine life is older than terrestrial life, and as all marine life

has shaped itself in relation to the pelagic food supply, this itself

is the only form of life which is independent, and it must therefore

be the oldest. There must have been a long period in primeval

times when there was a pelagic fauna and flora rich beyond limit

in individuals, but made up of only a few simple types. During

this time the pelagic ancestors of all the great groups of animals

were slowly evolved, as well as other forms which have left no

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. u

282 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

descendants. So long as life was restricted to the surface no great
or rapid advancement, through the influences which now modify
species, was possible, and we know of no other influences which
might have replaced them. We are, therefore, forced to believe
that the differentiation and improvement of the primitive flora and
fauna was slow, and that, for a vast period of time, life consisted
of an innumerable multitude of minute and simple pelagic organ-
isms. During the time which it took to form the thick beds of
older sedimentary rocks, the physical conditions of the ocean
gradually took their present form, and, during a part at least of
this period, the total amount of life in the ocean may have been
very nearly as great as it is now, without leaving any permanent
record of its existence, for no rapid advance took place until the
advantages of life on the bottom were discovered.

We must not think of the populating of the bottom as a phy-
sical problem, but as discovery and colonisation, very much like
the colonisation of islands. Physical conditions for a long time
made it impossible, but its initiation was the result of biological
influences, and there is no reason why its starting-point should
necessarily be the point where the physical obstacles first disap-
peared. It is useless to speculate upon the nature of the physical
obstacles ; there is reason to think one of them, probably an im-
portant one, was the deficiency of oxygen in deep water.

Whatever their character may have been they were all, no doubt,
of such a nature that they first disappeared in the shallow water
around the coast, but it is not probable that bottom life was first
established in shallow water, or before the physical conditions had
become favourable at considerable depths.

1'he sediment near the shore is destructive to most surface
animals, and recent explorations have shown that a stratum of
water of very great thickness is necessary for the complete devel-
opment of the floating microscopic fauna and flora, and it is a
mistake to picture them as confined to a thin surface stratum.
Pelagic plants probably flourish as far down as light penetrates,
and pelagic animals are abundant at very great depths. As the
earliest bottom animals must have depended directly upon the
floating organisms for food, it is not probable that they first
established themselves in shallow water, where the food supply

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 283

is both scanty and mixed with sediment ; nor is it probable
that their estabUshment was delayed until the great depths had
become favourable to life.

The belts around elevated areas, far enough from shore to be
free from sediment and deep enough to permit the pelagic fauna
to reach its full development above them, are the most favourable
spots, and palaeontological evidence shows that they were seized
upon very early in the history of life on the bottom.

It is probable that colony after colony was established on the
bottom, and afterwards swept away by geological change like a
cloud before the wind, and that the bottom fauna which we know
was not the first. Colonies which started in shallow water were
exposed to accidents from which those in great depths were free ;
and in view of our knowledge of the permanency of the sea-floor
and of the broad outlines of the continents, it is now impossible
that the first fauna which became established in the deep zone
around the continents may have persisted and given rise to modern
animals. However this may be, we must regard this deep zone as
the birthplace of the fauna which has survived ; as the ancestral
home of all the improved metazoa.

The effect of life upon the bottom is more interesting than the
place where it began, and we are now to consider its influence
upon animals, all whose ancestors and competitors and enemies
had previously been pelagic. The cold, dark, silent, quiet depths
of the sea are monotonous compared with the land, but they
introduced many new factors into the course of organic evolution.

It is doubtful whether the animals which first settled on the
bottom secured any more food than floating ones, but they undoubt-
edly obtained it with less effort, and were able to devote their
superfluous energy to growth and to multiplication, and thus to
become larger and to increase in numbers faster than pelagic ani-
mals. Their sedentary life must have been favourable to both
sexual and asexual multiplication, and the tendency to increase by
budding must have been quickly rendered more active, and one of
the first results of life on the bottom must have been to promote
the tendency to form connected cormi, and to retain the connection
between the parent and the bud until the latter was able to obtain
its own food and to care for itself. The animals which first

284 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

acquired the habit of resting on the bottom soon began to multi-
ply faster than their swimming allies ; and their asexually produced
progeny, remaining for a longer time attached to and nourished by
the parent stock, were much more favourably placed for rapid
growth. As the animals of the bottom live on a surface, or at
least a thin stratum, while swimming animals are distributed
through solid space, the rapid multiplication of bottom animals
must soon have led to crowding and to competition, and it quickly
became harder and harder for new forms from the open water to
force themselves in among the old ones, and colonisation soon
came to an end.

The great antiquity of all the types of structure which are
represented among modern animals is therefore what we should
expect, for after the foundation of the fauna of the bottom was
laid it became, and has ever since remained, difficult for new forms
to establish themselves.

Most of our knowledge of the sea bottom is from three
sources : from dredgings and other explorations ; from rocks which
were formed beyond the immediate influence of continents ; and
from the patches of the bottom fauna which have gradually been
brought near its surface by the growth of coral reefs ; and from all
these sources we have testimony to the density of the crowd of
animals on favourable spots. Deep-sea explorations give only the
most scanty basis for a picture of the sea bottom, but they show
that animal life may thrive with the dense luxuriance of tropical
vegetation, and Sir Wyville Thomson says he once brought up at
one time on a tangle which was fastened to a dredge over twenty
thousand specimens of a single species of sea urchin. The number
of remains of palaeozoic crinoids and brachiopods and trilobites
which are crowded into a single slab of fine-grained limestone is
most astounding, and it testifies most vividly and forcibly to the
wealth of life on the old sea-floor.

No description can convey any adequate conception of the
boundless luxuriance of a coral island, but nothing else gives such
a vivid picture of the capacity of the sea-floor for supporting life.
Marine plants are not abundant on coral islands, and the animals
depend either directly or indirectly upon the pelagic food-supply,
so that their life is the same in this respect as that of animals in
the deep sea far from land.

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 285

The abundant life is not restricted to the growing edge of the
reef, and the inner lagoons are often like crowded aquaria. At
Nassau my party of eight persons found so much to study on a
little reef in a lagoon close to our laboratory that we discovered
novelties every day for four months, and our explorations seldom
carried us beyond this little tract of bottom. Every inch of the
bottom was carpeted with living animals, while others were darting
about among the corals and gorgonias in all directions. But this
was not all, for the solid rock was honeycombed everywhere by
tubes and burrows, and when broken to pieces with a hammer
each mass of coral gave us specimens of nearly every great group
in the animal kingdom. Fishes, Crustacea, annelids, mollusca,
echinoderms, hydroids, and sponges could be picked out of the
fragments, and the abundance of life inside the solid rock was
most wonderful. The absence of pelagic life in the landlocked
water of coral islands is as impressive and noteworthy as the
luxuriance of life upon and near the bottom.

On my first visit to the Bahama Islands I was sadly disap-
pointed by the absence of pelagic animals, where all the conditions
seemed to be peculiarly favourable The deep ocean is so near
that, as one cruises near the inner sounds past the openings
between the islets which form the outer barrier, the deep blue
water of mid-ocean is seen to meet the white sand of the beach,
and soundings show that the outer edge is a precipice as high as
the side of Chimborazo and much steeper.

Nowhere else in the world is the pure water of the deep sea
found nearer land or more free from sediment, and on the days
when the weather was favourable for outside collecting we found
siphonophores and pteropods, pelagic molluscs and Crustacea and
tunicates and all sorts of pelagic larvae in great abundance in the
open water just outside the inlets.

Inside the barrier the water was always calm, and day after day
it was as smooth as the surface of an inland lake. When I first
entered one of these beautiful sounds, where the calm, transparent
water stretches as far as the eye can reach, while new beauties of
islets and winding channels open before one as those which are
passed fade away on the horizon, I felt sure that I had at last
found a place where the pelagic fauna of mid-ocean could be

286 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

gathered at our door and studied on shore. The water proved to
be not only as pure as air, but almost as empty. At high water we
sometimes captured a few pelagic animals near the inlets, but we
dragged our surface nets through the sounds day after day only to
find them as clean as if they had been hung in the wind to dry.
The water in which we washed them usually remained as pure and
empty as if it had been filtered, and we often returned from our
towing expeditions without even a copepod or a zoea or a pluteus.

The absence of the floating larvae is most remarkable, for the
sounds swarm with bottom animals which give birth every day to
millions of swimming larvae. The mangrove swamps and the
rocky shores are fairly alive with crabs carrying eggs at all stages
of development, and the boat passes over great black patches of
sea-urchins crowded together by thousands. The number of
animals engaged in laying their eggs or hatching their young is
infinite, yet we rarely captured any larvae in the tow net, and most
of these we did find were well advanced and nearly through their
larval life.

It is often said that the water of coral sounds is too full of
lime to be inhabited by the animals of the open ocean ; but this is
a mistake, for the water is perfectly fit for supporting the most
delicate and sensitive animals, and those which we caught outside
lived in the house in water from the sounds better than in any
other place where I ever tried to keep them, and instead of being
injurious the pure water of coral sounds is peculiarly favourable
for use in aquaria for surface animals.

The scarcity of floating organisms can have only one explana-
tion. They are eaten up, and competition for food is so fierce
that nearly every organism which is swept in by the tide and nearly
every larva which is born in the sounds is snatched by the tenta-
cles around some hungry mouth.

Nothing could illustrate the fierceness of the struggle for food
among the animals on a crowded sea-bottom more vividly than the
emptiness of the water in coral sounds where the bottom is practi-
cally one enormous mouth. The only larvae which have much
chance to establish themselves for life are those which are so for-
tunate as to be swept out into the open ocean, where they can
complete their larval life under the milder competition of the

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 287

pelagic fauna, and while it is usually stated that the larvae of bottom
animals have retained the pelagic habit for the purpose of distri-
buting the species, it is more probable that it has been retained on
account of its comparative safety.

These facts show that competition must have come quickly
after the establishment of the first fauna on the bottom, and that
it soon became very rigorous and led to severe selection and rapid
modification ; and we must also remember that life on the bottom
brought with it many new opportunities for divergent specialisation
and improvement. The increase in size which came with the
economy of energy increased the possibilities of variation, and led
to the natural selection of peculiarities which improved the efficacy
of the various parts of the body in their functions of relation to
each other, and this has been an important factor in the evolution
of complicated organisms.

The new mode of life also permitted the acquisition of pro-
tective shells, hard-supporting skeletons, and other imperishable
parts, and it is therefore probable that the history of evolution in
later times gives no index as to the period which was required to
evolve from small, simple pelagic ancestors the oldest animals
which were likely to be preserved as fossils.

Life on the bottom also introduced another important evolu-
tionary influence : competition between blood-relations. In those
animals which we know most intimately, divergent modification,
with the extinction of connecting forms, results from the fact that
the fiercest competitors of each animal are its closest allies, which,
having the same habits, living upon the same food, and avoiding
enemies in the same way, are constantly striving to hold exclusive
possession of all that is essential to their welfare.

When a stock gives rise to two divergent branches, each
escapes competition with the other so far as they differ in structure
or habits, while the parent stock, competing with both at a disad-
vantage, is exterminated.

Among the animals which we know best, evolution leads to a
branching tree-like genealogy, with the topmost twigs represented
by living animals, while the rest of the tree is buried in the dead
past. The connecting form between two species must therefore be
sought in the records of the past or reconstructed by comparison.

288 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

Even at the present day, things are somewhat different in the
open ocean, and they must have been very different in the prim-
itive ocean, for a pelagic animal has no fixed home, one locality is
like another, and the competitors and enemies of each individual
are determined in great part by accidents.

We accordingly find, even now, that the evolution of pelagic
animals is often linear instead of divergent, and ancient forms,
such as the sharks, often live on side by side with the later and
more evolved forms. The radiolarians and medusae and siphono-
phores furnish many well-known illustrations of this feature of
pelagic life.

No naturalist is surprised to find in the South Pacific or in the
Indian Ocean a salpa or a pelagic crustacean or a surface fish or a
whale which was previously known only from the North Atlantic,
and the list of species of marine animals which are found in all
seas is a very long one. The fact that pelagic animals are so
independent of those laws of geographical distribution which
limit land animals, is additional evidence of the easy character
of the conditions of pelagic life.

One of the first results of life on the bottom was to increase
asexual multiplication and to lengthen the time during which buds
remain united to and nourished by their parents, and to crowd
individuals of the same species together, and to cause competition
between relations. We have in this and other obvious pecuHarities
of life on the bottom a sufficient explanation of the fact that since
the first establishment of the bottom fauna, evolution has resulted
in the elaboration and divergent specialisation of the types of
structure, which were already established, rather than the pro-
duction of new types.

Another result of the struggle for existence on the bottom was
the escape of varieties from competition with their allies by flight
from the crowded spots, and a return to the open water above ;
just as in later times the whales and sea-birds have gone back from
the land to the ocean. These emigrants, like the civilised men
who invade the homes of peaceful islanders, brought with them
the improvements which had come from fierce competition, and
they have carried everything before them and produced a great
change in the pelagic fauna.

THE ORIGIN OF THE OLDEST FOSSILS, ETC. 289

The rapid intellectual development which has taken place
among the mammals since the middle tertiary, and the rapid
structural changes which took place in animals and plants when
the land fauna and flora were established, are well known ; but
the fact that the discovery of the bottom initiated a much earlier,
and probably more important, era of rapid development in the
forms of animal life has never been pointed out.

If this view is correct the primitive fauna of the bottom must
have had the following characteristics :

I. — It was entirely animal, without plants, and it, at first, de-
pended directly upon the pelagic food supply.

2. — It was established around elevated areas, in water deep
enough to be beyond the influence of the shore.

3. — The great groups of animals were rapidly established from
pelagic ancestors.

4. — The animals of the bottom rapidly increased in size and
hard parts were quickly acquired.

5. — The bottom fauna soon produced progressive development
among pelagic animals.

6. — After the establishment of the fauna of the bottom, elabo-
ration and differentiation among the representatives of each primi-
tive type soon set in and led to the extinction of connecting forms.

Many of the oldest fossils, like the pteropods, are the modified
descendants of ancestors with hard parts, and there is no reason to
suppose that the first animals which were capable of preservation
as fossils have been discovered, but it is interesting to note that
the oldest known fauna is an unmistakable approximation to the
primitive fauna of the bottom.

The lower Cambrian fossils are distributed through strata more
than two miles thick, some, at least, of them showing by their fine
grain and by the perfect preservation of tracks and burrows which
were made in soft mud, and of soft animals like jelly-fish, that they
were deposited in water of considerable depth. The sediment
was laid down slowly and gently in water so deep as to be free from
disturbance, and under conditions so favourable that it contains
the remains of delicate animals not often found as fossils.

While the fauna of the lower Cambrian undoubtedly lived in
water of very considerable depth, it was not oceanic, but continen-

290 THE ORIGIN OF THE OLDEST FOSSILS, ETC.

tal, for we are told by Walcott that " one of the most important
conclusions is that the fauna of the lower Cambrian lived on the
eastern and western shores of a continent that in its general con-
figuration outlines the American continent of to-day." " Strictly
speaking, the fauna did not live upon the outer shore facing the
ocean, but on the shores of interior seas, straits, or lagoons that
occupied the intervals between the several ridges that ran from the
central platform east and west of the main continental land surface
of the time."

This fauna was rich and varied, but it was not self-supporting,
for no fossil plants are found, and the primary food supply was
pelagic. Animals adapted for a rapacious life, such as the ptero-
pods, were abundant, and prove the existence of a rich supply of
pelagic animals. All the forms known from the fossils are either
carnivorous — like the medusae, corals, Crustacea, and trilobites — or
they are adapted — like the sponges, brachiopods, and lamelli-
branchs — for straining minute organisms out of the water, or for
gathering those which rain down from above, and the conditions
under which they lived were very similar to those on the bottom
at the present day.

Walcott's studies show that the earliest known fauna had the
following characteristics : — It consisted, so far as the record shows,
of animals alone, and these were dependent upon the pelagic food
supply for support. While small in comparison with many modern
animals, they were gigantic compared with primitive pelagic ani-
mals. The species were few, but they represent a very wide range
of types. All these types have modern representatives, and most
of the modern types are represented in the lower Cambrian.
Their home was not the bottom of the deep ocean, but the shores
of a continent under water of considerable depth.

The Cambrian fauna is usually regarded as a half-way station in
a series of animal forms which stretches backwards into the past for
an immeasurable period, and it is even stated that the history of life
before the Cambrian is longer by many fold than its history since.

So far as this opinion rests on the diversity of types in Cambrian
times, it has no good basis ; for if the views here advocated are
correct, the evolution of the ancestral stems took place at the
surface, and all the conditions necessary for the rapid production

FLOSCULARIA HOODII. 291

of types were present when the bottom fauna first became estab-
lished.

As we pass backwards towards the lower Cambrian, we find
closer and closer agreement with the zoological conception of the
character of primitive life on the bottom. While we cannot regard
the oldest fauna which has been discovered as the first which
existed on the bottom, we may feel confident that the first fauna of
the bottom resembled that of the lower Cambrian in its physical
conditions and in its most distinctive peculiarities ; the abundance
of types, and the slight amount of differentiation among the
representatives of these types ; and we must regard it as a decided
and unmistakable approximation to the beginning of the modern
fauna of the earth, as distinguished from the more ancient and
simple fauna of the open ocean.

3flo0culana Iboo&ii.

By John Hood, F.R.M.S., Dundee. PL XIV.

THIS large and strange Eotatorian was found by me for the
first time in December, 1882, attached to Sphagnum^ in a
ditch on Tents Muir, Fifeshire. The large size of the
rotifer, and its possessing a corona unlike any other species of the
genus Floscularia^ together with its great cowl-shaped, dorsal lobe,
would make it sufficiently remarkable ; but in addition to the two
extraordinary finger-shaped processes, perched one on each side of
the summit of the dorsal lobe (PI. XIV., Figs, i and 2, d. p.),
there are two very significant organs possessed by no other species
of the genus. It has been, indeed, suggested to me that ibis
species should be removed from the genus Floscularia and placed
in a new genus by itself. But with the exception of the finger-like
processes, the other organs are identical with those of a true
Floscule, so I therefore think it should be retained in that genus.

Dr. Hudson described this Eotatorian from living specimens,
which I sent him from Dundee on the 25th December, 1882. His
description, with two figures, were pubUshed in the Journal of the
Royal Microscopical Society^ II. Series, Vol. III., pp. 161 — 171,

292 FLOSCULARIA HOODII.

PI, III. In his description he says: — "I cannot yet hazard a
suggestion as to the function that these finger-hke processes
perform."

As I have since had frequent opportunities of observing this
creature in various stages of its development, I desire in the
present paper to supplement Dr. Hudson's description. The
finger-hke processes are hollow tubes open at the points. The
upper end of each of these processes is slightly constricted ; the
tubes communicate with two sub-spherical spaces lying between
the two surfaces of the dorsal lobe. Fine muscular threads pass
down and across the tubes ; the threads run down from their base
on the dorsal side to the neck below the vestibule. The animal
can contract each of these tubes independently of the other, and
can put them in different positions ; there is not a trace of setae at
their apex to suggest their function as antennae or feelers. The
lateral antennae are situated in the same region to those of the
other species of Floscularia. Their function is doubtless that of
excretory organs.

I have frequently observed that both the adult and young
individuals discharge a granular mucous matter through these
finger-like processes, which gathers round their free extremities, as
shown in PI. XIV., Fig. 2, g, m, and is not got rid of until the
animal retires into its tube, where it is rubbed off to increase the
volume of the creature's fluffy domicile ; when the afiimal again
emerges from its tube, the free ends of the finger-like processes
are quite freed from the accumulation.

The cuticle of the trunk and coronal cup of 7^ Hoodii is com-
posed of two layers, an outer and an inner membrane, tough and
elastic, and between the two layers is a fluid more or less granular.
The granular fluid may be seen in some degree in every species,
but more conspicuously in F. a??ibigtia, F. algicola, and F amiu-
lata. In these the fluid is rendered semi-opaque by the large
number of granules floating therein ; but in the case of F. Hoodii
the granules in the fluid are not so numerous, and consequently
the creature is more transparent than the other species. It is
doubtless by means of this fluid that the lobes of the furled corona
are pushed forward and expanded, especially as it has inter-com-
municating cavities and channels containing fluid, which is driven

FLOSCULARIA HOODII. 293

upwards and downwards by the contractions of the muscles and
by the various motions of the body ; the transverse muscles of the
trunk force the fluid into definite channels, rendering the lobes
tight and stiff, like the ribs of an umbrella.

Doubtless the function of the finger-shaped processes on the
back of the dorsal lobe is to excrete a portion of the inter-mem-
branal fluid, which is then utilised in the construction of the fluffy,
gelatinous tube; and although no other species is known to possess
similar appendages, it cannot be said that the excretion of this
fluid is confined exclusively to F. Hoodii^ for there will be observed
on the back of the dorsal lobes of F. irilobata and F. ambigua a
single knob, and on the back and near the top of the dorsal lobe
of F. cucullata will be seen two slight prominences, which are
probably used for a similar purpose. The granules in the mucous
matter discharged have a very active swarming motion while they
cling round the free ends of the finger-like processes. This
swarming motion is not observed in the mucous fluid within the
two membranes of the skin in either of the lobes or the trunk. It
is only when the mucous matter is set free that the swarming, or
Brownian, motion of the granules is observable.

Sometimes when the animal is fully protruded from its fluffy
tube, only one of the processes is seen to be fully distended ; the
other will be observed lying flat on the dorsal lobe ; then, in a
short time, it also will be slowly raised and distended.

The corona is large and globular, and when fully expanded
shows a large, mouth-like funnel of three lobes, two small ones
being on the ventral, and one, much the largest, on the dorsal
side. The rims of the three lobes are clothed with a double
fringe of setae. The setae of the outer row are long and are
directed outwards. Those of the inner row are much shorter and
point inwards. The gap of the mouth-funnel alters frequently.
The food of these creatures consists of living animalcules of
various dimensions, one or more of which may be seen swimming
at the same time within its large circular cavity. To prevent the
escape of its victims, when the animalcules are of large size and
swift swimmers, the floscule closes the gap by means of the many
muscular threads on the corona, so as to reduce the aperture in
various degrees, at times even reducing it to a mere slit.

294 flOkSCUlaria hoodii.

In consequence of the transparency of the corona, the semi-
circular wreath of the vibratile ciUa at the bottom of the vestibule
is easily seen. With the exception of F. trilobafa, very few, if any,
other species afford the same facility.

In a side or lateral view of the floscule, on the dorsal surface,
will be seen a pair of transparent ridges, which run up from the
back of the trunk to the back of the dorsal lobe. These are sug-
gestive of buttresses between the trunk and coronal head, shown
in PI. XIV., Fig. i, r. Between these ridges there is a deep
hollow, bounded above by the dorsum and below by the rounded
surface of the body. At the lowest portion of this hollow, which
forms the neck, close to the buttress ridges, are two small red eyes,
which are present both in the young and in the adult individuals,
and are only seen, both at the same time, in a dorsal aspect. One
eye only is seen in a lateral view on either side, but cannot be seen
at all in the ventral view (see Fig. i, e).

The true rotatory organ of F. Hoodii, which consists, as in
other species, of a ciliated rim at the base of the mouth-funnel,
towards the ventral side, is continued in two curved lines down
the vestibule to the lips. This organ is seen with greater facility
than in any other species, owing to the exceptional transparency of
the creature's large head.

The contractile vesicle is ample, and frequently contains yel-
lowish globules, which appear dark brown with transmitted light.
It deposits one to four large eggs in the fluffy tube close to the
foot. This species is the most interesting of the genus Floscularia
and the most hardy. It can be kept in a trough under the micro-
scope for a number of weeks, and the observer will not tire of
looking at it. It must be supplied with a change of water daily,
which should be taken from an aquarium where there is present
an ample supply of food in the form of living Infusorians. The
observer never fails to be entertained by watching the creature's
manner in feeding. Sometimes three of four small animalculae
will enter the open mouth-funnel at one time. These the floscule
will swiftly swallow one after the other in rapid succession. Then,
again, a large-sized Infusorian wiU dash into the cavity, where it
will be seen to swim rapidly round and round in the coronal cup,
like a minnow newly introduced into a fish-globe. Then, after a

Journal of Microscopy N.S.Vol.5. Plate 14^.

THcuisoa end not. dec.

Floscwlaricu Ilooolhiy.

rphiiiips Sc.

FLUSCULARIA HOODII. 295

time, the floscule will be observed to be slowly closing the aper-
ture to prevent the escape of the vigorous animalcule, which has
made the fatal mistake of entering the alluring flower-like cup.

F. Hoodii inhabits a large, clear, transparent tube, and finds a
suitable environment either in a marsh pool or lake. The first
examples found were attached to SphagJium collected from a marsh
ditch on Tents Muir, Fifeshire ; then, again, on Myriophyllum,
dredged from the centre of Loch Lundie, Forfarshire ; and on
Ra7i2inculus from Blacklock, Blairgowrie, Perthshire, and recently
on Ranunculus^ dredged from a lake in co. Mayo, Ireland.

It is to be regretted that this handsome rotiferon is so rare, yet
it is fairly well distributed, for I have found it in three counties in
Scotland and also in the West of Ireland. Examples have also
been found in Wiirtemberg, Germany, by Herr L. Bilfinger, who
found a number on My7'iophyUum on the 28th of September,
1890, an account of which is published in his List of Rotatorien-
fau7ia Wurte?nbergs, 1892, and is the only other published record
of this animal that I am aware of since the Monograph on Roti-
fera^ by Dr. Hudson and P. H. Gosse, published in 1886.

Literature relating to Floscularia Hoodii:

C. T. Hudson, LL.D., F.R.S., F.R.M.S.— "On Five New
Floscules ; with a Note on Prof. Leidy's genera, Acyclus and Dic-
tyophora^'' Journal of the Royal Microscopical Society^ 1883, pp.
161— 171, Pis. III. and IV.

Dr. Hudson and P. H. Gosse, "The Rotifera or Wheel Ani-
malcules," 1886, p. 55.

Von L. Bilfinger, '•''Zur Rotatorienfauna Wilrfembergs,^^ 1892,
p. 110, /ahreshefte des Vereinsfiir Vaterl. Natur. ift Wiirtemberg.

EXPLANATION OF PLATE XIV.

Fig. 1. — Lateral view, d.p., Dorsal processes, e. , The position of the
eyes in the neck, r., Transparent dorsal ridge.

2. — Ventral view, (/.m., Granular mucous matter excreted from
the free ends of the dorsal processes.

Figures by Dr. Hudson.

5)

[ 296 ]

©liver Mcn5cU Ibolnice & tbe flDicro9cope,

IN a recent number of the New York Medical Journal (lxl,
1895, pp. 236 — 9), Dr. Palmer C. Cole relates some of his
microscopical reminiscences, one of which gives a view of
the Autocrat of the Breakfast Table as a Microscopist. Dr. Cole
says : " It was my good fortune to be a student of the Harvard
Medical School when Oliver Wendell Holmes was professor of
anatomy and physiology. Professor Holmes was an enthusiast in
the use of the microscope, and possessed some of the finest of the
Spenser lenses, then the best in the world. He had constructed
a stand, principally of wood, stable enough to allow the use of
high-power objectives, and so simple that any student with the
slightest mechanical ability could make one for himself. My first
stand I made on this model at a cost of about fifty cents for
material.

The coarse adjustment was obtained by means of a pin in the
tube carrying objective and eyepiece, which was pushed against a
wedge-shaped piece of brass. The fine adjustment was obtained
by revolving the pin against the wedge. Over the tube was
slipped a cardboard disc, some six to eight inches in diameter,
covered with black velvet, allowing both eyes to be kept open
during observation. The tube was also lined with black velvet.
The tube-support revolved on a pivot, allowing inclination, though
we were taught to use it with direct light. In a recent letter to
me, Oliver Wendell Holmes refers to this stand as ' a rough
wooden contrivance that answered its purpose.' Later, Holmes's
lecture-room microscope, for use in his own class, became very
popular, and is still extensively used.

Notwithstanding his engagements with others in founding the
Atlantic Monthly ^ his medical lectures five days a week, an occa-
sional public lecture, and monthly instalments in the Atlantic of
that brilliant series of essays. The Autocrat of the Breakfast Table^
he found time at his own house in Montgomery Place, to give
weekly instruction to half-a-dozen chosen students in the use of
the microscope. In 1856 and 1857, I was fortunate enough to
be one of the chosen half-dozen. We were taught the use of the

O. W. HOLMES AND THE MICROSCOPE. 297

instrument and the preparation of slides. The slides used from
week to week were prepared by Holmes himself, to show the dif-
ferent tissues of the body. The only consideration ever given for
these charming and instructive lessons were the grateful thanks of
his pupils.

I believe that Oliver Wendell Holmes was the first in America
to teach classes of medical students the use of the microscope.
If so, to him, and through him to the Harvard Medical School,
should be accorded the honour.

Since writing the above, Oliver Wendell Holmes has passed
away. None knew him but to love him. His anatomical and
physiological lectures were charming, and always filled the amphi-
theatre ; even dry bones in his hands became endowed with life
and individuality.

It was my rare good fortune to be occasionally invited to his
house, where I spent some delightful hours in his study and work-
room. Once I was present when a large package of books arrived
from New York for his inspection, which I helped him unpack.
When at the bottom of the case we came upon a large folio copy,
original edition, of Vesalius, his eyes fairly sparkled with joy.
Hastily he turned over the leaves, and remarked that, as New
Yorkers have been fools enough to allow such a prize to leave their
city, it would never return from Boston.

All the world knew him as professor, author, and poet, but
few knew his fondness for music, and that he possessed a rare
mechanical genius of which he was very proud. He once told me
he thought more of the 'gimcracks' he made with his hands
than of anything he had ever written ; and at that time he was
delighting two hemispheres with The Autocrat of the Breakfast
Table.

In his last autograph letter to me he says : 'My most success-
ful contrivance was a stereoscope of a very simple pattern, which
had a great run, and has remained popular, I think, to the present
time.' "

International Journal of Microscopy and Natural Science.
Third Series. Vol. V.

[ 298 ]

Britlab Ibpbracbnib^,

Part II. By Charles D. Soar, Plate XV.

^"^HE next genus we have to notice is the well-known Arre7iii
rus. I say well known, because this genus was described in
extenso in a series of articles which appeared in Science
Gossip some years ago, written by Mr. C. F. George, of Kirton
Lindsey. The genus Arrenurus contains mites of the most
beautiful shapes and colours, the colours being especially brilliant,
some of them appearing quite metallic, and look most gorgeous
when viewed under reflected light. In shape the males are as
different from the females as it is possible to imagine. This genus,
when thoroughly worked out, will, I have no doubt, be found to
be the most prolific in species of all the British Hydrachnidae. A
great many species are very common. No collector or lover of
pond-life but has at some time or other taken some of these
interesting and prettily coloured mites home in his bottle, perhaps
admired them, and put them on one side and thought no more
about them ; very few naturalists have thought it worth while to
write about them.

If the reader who is interested in this genus will turn to Science
Gossip for the years 1881 to 1884 (Vols. XVIL— XX.), he will
find several papers devoted to this family by Mr. C. F. George,
who described and figured about sixteen of the species found in
the British Isles. My intention, however, in this paper is to speak
of the genus and give its characteristics, so that anyone will know
an Arrenurus when they find one. The number of known British
species I hope to give later on.

Genus Arrenurus (Duges).
(A. Duges, Recherches sur I'ordre des Acariens, etc., Ann, des
Sciences Nat.,, Tom. I., p. 17, 1834.)
Body chitinous, with a maculated appearance in both sexes.
On the dorsal side is a depressed line, which is oval in shape in
the female and of a horse-shoe shape in the male. The legs are
strong and well supplied with swimming bristles. All the tarsi
have claws. Mandibles in two distinct portions. Eyes widely
separated and near margin of body. On each side of the opercu-
lum are numerous copulative pores set in a special plate. Palpi
short, the fourth joint longer and stronger, the fifth joint forming

Journal of Microscopy N. S.Vol. 5. Plate 15.

Chas. D. Soar ac/ nsit de/.

f:Fhi/iips Sc-

ArrenzcrcC'S alodator.

BRITISH HYDRACHNID^. 299

a thumb and finger. As an illustration of this genus, we give the
following description of A. globator : —

Arrenurus globator (Miiller).

1776. — Hydrachna globator. Miiller, Zool. Dan. Prodr., p. 188,

No. 2242.
1 781. — Hydrachna globator. Ibid., Hydrachnse, p. 37, Tab. 2,

Figs. 1—5.
1793. — Trombidium variater. J. C. Fabricius, Ent. Syst., Tom. II.,

p. 403, No. 22.
1805. — Atax variater. Ibid., Syst. Antliatorum, p. 369.
1835. — Arrenurus globator. C. L. Koch, Deutschlands Crust.,

etc., p. 13, Figs. 22, 23.
1854. — Arrenurus globator. Bruzelius Beskr. o. Hydrachn. som.

Forek. i. Skane, p. 31, Tab. III., Fig. 3.
1879. — Neuman Sveriges Hydrachnides, p. 88, Tab. X., Fig. 2.
1882. — C. F. George, Science Gossip, XVIII. , p. 272, Figs 194 —

202.

Male. — This beautiful mite cannot very well be mistaken for
any other form. It has a globular process on the dorsal side of
the tail, from which it takes its name. Colour, a light delicate
green, wdth brown markings. Eyes, deep crimson. On the fourth
joint of the fourth leg is a peculiar development, often, but not
always, seen in the males of the species of Arrenurus. This is a
very small mite, its length being only 3/iooth of an inch.

Fetnale. — Almost oval in shape, with indentations on each
side. Same colour as the male — pale delicate green, with brown
markings. Length, 1/2 5th of an inch, being a little larger than
the male.

This mite is by no means uncommon ; I have found it several
times. The two specimens from which the drawings (PI. XV.)
were made were found at Snaresbrook on one of the Quekett
excursions Sept. 2 9th^ 1894. Having a chitinous epidermis, these
mites can easily be mounted in Canada balsam, and if the legs are
regularly arranged they make very pretty mounts, the delicate
colouring bemg brought out by the balsam even more brilliantly
than in life. Koch describes about forty species, but some have
since been removed to other genera.

EXPLANATION OF PLATE XV.

Fig. 1.— Dorsal view of Male. Fig. 4.— Palpi of Male.

,, 2. — Ventral view of do. ,, 5. — Dorsal view of Female.

,, 3. — Side view of do. ,, 6. — Ventral view of do.

[ 300 ]

Bacteria of tbe Sputa an& Cri^ptogamic
3flora of tbe fIDoutb,

By Filandro Vicentini, M.D., Chieti, Italy.

SECOND MEMOIR.
Translated by Professor E. Saieghi.

IRecent Bactertologtcal IResearcbes ow tbe Sputa ;
tbe /IDorpbolog^ anb JBtolOGp of tbe /liMcrobeB
of tbe /IDoutb.

Further Remarks on the Bacteria and Bacilli found

IN THE Sputa.

Fructification by Spores (Ears) Reproduced in

the Sputa.

1WILL now deal with the reproduction of the fructification by
spores (spicae) in the sputa. Hitherto we have been unable
to obtain cultures of Leptothrix^ and microbes of the mouth in
general, upon the usual artificial soils ; and on this point the
authors, from Cornil and Babes to the more recent, are agreed.*
It will not be inopportune to point out a case of fructification by
ears, reproduced in a specimen of sputum, which induced me to
make the present communication.

The presence of filaments, isolated or intertwined, of Lepto-
thrix, in the sputa, is well known in clinical microscopy. Leyden
and Jaffe recognised even Leptothrix piilmonaris ; and Hunter
Mackenzie exhibits a conspicuous specimen taken from tuber-
cular sputum during a time of improvement. t In the sediment
of masses of sputa, emulsified with potash, we find not only
little rods and filaments, but even numerous tufts of this parasite.
I remember also having often found in sputa of every kind
freshly stained fragments which I had not known before, and
which were portions of ears spoiled in the preparation.

The case which gave the conspicuous specimen, delineated in
Fig. 1 6, was the following : —

* Cornil and Babes, op, cit.y p. 135.

t Leyden and Jafife, Deutsches Archiv fur Med., II., p. 488; Hunter
Mackenzie, Le Crachat^ etc., trans., Paris, 1888, Fig. 22.

BACTERIA IN THE SPUTA, ETC. 301

Mr. G. F., 41 years of age, having already been twice attacked
by obstinate miasmatic affections, and once by an acute affection
of the air-passages (the nature of which he does not remember), fell
ill last March with very high fever (from 40*6° to 41 "2° in the
evening hours, falling about a degree in the morning) ; with serious
dyspnaea (from 45 to 50 breathings a minute), and very rapid pulse
(135 — 145). On the chest it was only noticed that the right apex
was less sonorous, giving an indistinct respiratory murmur ; Httle
coughing, with scanty and infrequent expectoration ; tumour of
the spleen by percussion, but probably chronic. The sensorium
sound ; a little insignificant epistaxis ; remarkable bilious diarrhoea.
Albumen, one and a-half grammes to every pint of urine, with a
few hyaline and granular urinary casts, and increase of ordinary
pigments.

In the first days there was a doubtful expectoration, which was
thought to proceed from the nose. An eruption of herpes labialis
appeared (which I remember having deceived me in a case
of ileo-typhus). At any rate, the diagnosis of ileo-typhus was
given, and three baths were prescribed which gave great relief.
On the seventh day the fever suddenly subsided, as generally
happens in pneumonia. Dyspnoea remained, only diminished by
the quota due to fever ; and in thirty-six hours 1 obtained a small
quantity of rusty sputa, a portion of which, nearly free from saliva,
I examined, to ascertain whether it proceeded from the air-passages.

The diagnosis was made even clearer when, later on, crackling
wheezings and murmurs of friction in unison with the beatings of
the heart (pleuro-pericardiac friction of Wintrich) became mani-
fest ; these continued up to the sixteenth day of the illness. I
have met with this phenomenon on other occasions, in pleurisy
or in pleuritic granuloma, but on the left side ; here, on the con-
trary, it was heard on the right upon the line of the sternum, and
below towards the mammillary line. Consequently, the grave
dyspnoea had been the means of spreading the process to the
pleuritic coating of the pericardium, and perhaps to a limited part
of the pericardium itself. At any rate, the examples of a great
disproportion between the extension of the local and the magni-
tude of the general facts are not rare, especially when the apices of
the lungs are affected with pneumonia.

302 BACTERIA IN THE SPUTA

The following were the elements found in the sputum : a fair
number of red blood corpuscles, both isolated and in small clusters ;
here and there a great gathering of ellipsoidal epithelia (so-called
alveolar), mostly with a coat of granules of myelin, and a few free
particles of the same ; many cylindrical and vibratile epithelia of
the air passages ; the usual buccal epithelia ; a few slender and
short spires of Curschmann ; myriads of uncapsulated pneumo-
cocci, generally in vast cumuli ; small well-defined groups of
capsulated pneumococci, after type in Fig. 4, /; various other
forms of bacteria and bacilli ; filaments, and even tufts, of Lep-
toihrix ; groups and large cumuli of spores and sprouts of oidium
( Oidiiwi ladis ?) .

As it is my custom to keep the sputa for whole weeks in
order to repeat my investigations, on the seventh day after col-
lecting this sputum I detected in it fragments of fructifications,
which I could perfectly well recognise. 'I then thought of remov-
ing a particle of the patina of the sputum, which was adhering to
the internal wall of the tube, to that side on which I had always
inchned it, in collecting the specimens. There the layer of the
mAicus was very thin and wet, the tube being accurately closed.
This mucous patina, having been adhesive and undisturbed for
several days, ought to have preserved nearly the same conditions
favourable to the fructification of Leptothrix, as seen on the
patina of the teeth. That layer appeared to the naked eye opaque
and greyish, like a very delicate mould.

The result of that research could not have been more satisfac-
tory, as Fig. 16 shows. It extends over two visual fields (magnified
850 diameters), and the colouring of ears with gentian violet
is very striking, the particle of the sputum having been immersed
for two hours in the liquid stain, then washed and mounted in dis-
tilled water. It will be observed at a glance that the bundle of ears
has been severed in two groups : in the superior one, A, all the
stalks are preserved; in the inferior, B^ only five are visible. The
fructifications or part of them, as well as the missing stalks, were
spread here and there over the surrounding visual fields. The
inferior group, B^ has been pressed sideways by the cover-glass,
and lies in profile with its base down ; the superior one, A^ has
been pressed down vertically by the cover-glass, and is conse-

AND CONTENTS OF THE MOUTH. 303

queiitly opened and formed into two, so that it shows five upper
stems with the base downwards, and two lower stems, /and ^,
with the base upwards.*

In the largest stalk, «, the gemmules of reserve are distinctly
observed, and these are still better seen in a\ where a part of that
stalk is reproduced (magnified to 2,500 diameters) after a long
saturation in glycerine (see later on). In ^, the ear is partially
scattered, so that a few spores remain in situ, and the stalk is
entirely visible. In d and <?, cumuli of sporules are seen in those
points where the ears are partially scattered. Then from the
concussion the sporules are driven towards the top, leaving bare
the stalk near the base. In c, the ear is broken, and shows a clear
section, but without its superior part.

In the patina dentaria I never came across ears so long
and perfect. In fact, the better kept ears^ bent down, in / and
g^ are the longest found hitherto; as that in /measures 166^, or one
sixth of a millimetre, which corresponds to one and a half the
thickness of a cover-glass, nine to the millimetre. The number
of the sporules implanted in these ears (upon six longitudinal
lines) may be calculated, at the lowest, to be 720.

We shall have, here, to consider two points. The first is, that
a similar specimen cannot be supposed to have been previously
formed on the teeth, then fallen in the expectoration with saliva,
to be found there second hand, as the fructifications do not rise
so high in the patina dentaria, nor could they have been so well
kept after the various manipulations. The circumstances under
which they were found incline rather to the belief that they had
germinated on the mucous film from filaments there deposited,
and were being fed from the materials of the sputum itself.

In the present case, we shall not take into consideration
whether the presence of red blood corpuscles may have favoured
the development of those ears. It is certain that they are found
more abundant in the patina dentaria of persons suffering from
tenderness of the gums, and whose teeth are, in the morning,
somewhat besmeared with blood.

The second point is that the specimen in question is sufficient
to clear up any doubt whatever about the nature of the above-

* In the Plate, Fig. 16^ is erroneously marked Fig. \\B.

304 BACTERIA IN THE SPUTA

described ears. Taking only the specimens obtained fronri the
patina dentaria, some doubts might remain, as in it the ears are,
generally, embedded in the granulous lumps and the entangle-
ments of threads, in consequence of the pressure of the lips or
tongue ; and we might suppose that they are the mechanical result
of that trampling or superposition of minute cocci around the
branching filaments, so as to become incrusted with them. But
(apart from the consideration that the incrustation cannot explain
the perfect similarity of the sporules, nor their constant disposi-
tion in six longitudinal lines) the specimen of Fig. i6 dispels any
suspicion whatever, as it is there manifestly the sign of a gen-
uine and proper germination ; nor, on the other hand, can there
be found a particle of resting place on which the stems might
have become incrusted.

In support of this view there is the fact that the ears acquire,
by colouring with aniline, such a solidity that they can hardly be
dissevered. The above-mentioned specimen, which, through the
accidental crushing of the preparation by a wrong turn of the fine
adjustment, was hard-pressed down, exhibits a proof of it. The
ear drawn in g was abruptly removed towards / and made into a
spire, but no spores were dropped by the shock, and the ear has
since gradually resumed its former place. Now this fact could
not be explained on the hypothesis of a simple mechanical
incrustation.

This preparation has been kept in glycerine, which was after-
wards substituted for the aqueous medium. The tint, especially of
the pneumococci without halo, is very much faded, owing to the
diffusion caused by glycerine. The ears^ after two months of
saturation, exhibited a partial decolourisation and withered spores,
although the stalks maintained a brilliant colour. The viscid
matter has become paler and more transparent, so that the stalks
can be detected fully in their whole length ; and inside can be
seen not only the gemmules, but traces of small knobs, shown in
a. By turning the micrometer screw I could even see, although
interruptedly, a few sporules belonging to the posterior series or
those lying on the slide.

In conclusion, having thoroughly investigated this preparation,
it seems to be absolutely impossible to dispute the fructification of

AND CONTENTS OF THE MOUTH. 305

those forms of Leptothrix and the fertility of their stems. This
specimen is at tiie disposal of anyone who wishes to examine it.

We shall, by-and by, deal with the fructification obtained from
urinary mucus.

With regard to the oidium forms found in this sputum, I will
say two words concerning their fructifications. I have dealt with
this argument formerly (see previous Memoir), and spoken about
cultures upon peels of lemons and various other nutrient media ;
but I have found it more expedient and satisfactory to let the
fungi of the sputum germinate in the sputum itself.

The better soil for cultures is that in which spores and branch-
ing filaments carry out their immersed vegetation. In order that
aerial vegetation should take place, two conditions are required :
the first is that the materials of culture (in this case, the sputum)
should be moderately dry on the surface ; and the second is that
the under layer, or the lowest stratum of the sputum, should be
kept wet in order to feed the vegetation. Now, both conditions
are fulfilled by placing a part of the sputum, impregnated with
spores and sprouts, on the bottom of a wine-glass slightly hollow,
so that the sputum should sufficiently spread and rise to four or
five millimetres. The wine-glass and its cover should be previ-
ously cleansed with sulphuric acid, and washed out with alcohol.
Through the wide opening of the glass the fructifications can be
easily observed and scraped out for microscopical examination.
Generally, fructification is completed on the fourth day, by keep-
ing the glass well sheltered in the dark.

The sputum, impregnated with oidium forms, exhibited on the
fourth day a simple fructification of Penicillium glaucum. Natu-
rally, we do not intend by this to discuss the question brougln
forward by Hallier — i.e.^ whether the oidium forms be one phase of
the Penicillium and Muco7' kinds.

Dissemination of the above-described Microbes on
THE Posterior Organs.

Considering now the extended vegetation and fructification of
Leptothrix upon the dental surface and superposed layers ; its
abundant germination on the tongue, its constant presence in the
epithelia of the cavities of the mouth and pharynx, its very active

306 BACTERIA IN THE SPUTA

multiplication in saliva, the countless swarms of analogical forms,
quiescent or reproductive, in the whole wide surface of the nasal
cavities, and perhaps of its appendages ; considering also the
extraordinary fertility of this parasite, and its multiplication not
only through the fission of cocci and bacteria, but through fructi-
fication and budding within the filaments, we may form an approx-
imate idea of the mass of germs or scattered elements which are
invading the digestive, aerial, and lachrymal passages.

According to my calculations, not less than from two to three
hundred trillions of germs or separated elements are generally
present in the mouth and nose, and liable to disseminate the
species, at every minute, into the other parts.

In fact, comparing the single sporules of the ears with the
dumb-bell bacteria of types «, I), c, d (Fig. 2), we should have to
place nearly eight sporules in two rows upon the surface of a single
bacterium in order to cover it. The bacterium is twice as thick as
the sporule ; consequently, the volume of one bacterium will be,
at least, equivalent to that of sixteen minute sporules. Now, in
our first Memoir, we have demonstrated that about 25 milliards
of bacteria of types a, b, c, d, go to form a centigramme in
weight ; then, for every centigramme of sporules, we shall
have to multiply the 25 milliards by 16, which will give 400
milliards of sporules for each centigramme. Calculating now
the considerable number of the dropped sporules, that of
the gemmules of reserve in the filaments, that of even the
most minute granules which constitute the bed of the branch-
ing threads and of the clods of Leptothrix ; calculating the very
small lineal germs grafted on the young productions by points^
we can safely maintain that their extreme minuteness compensates
for the larger volume of bacteria enclosed in the older filaments,
that of spindle-like, the comma, and the serpentine bacilli, as well
as of spirilli and cocci disseminated in every part. Thus, holding
the volume of the sporule as the unity of measure, taking the
whole patina of the thirty-two teeth as equivalent, at least,
to a gramme, we shall have the number of the elements and
germs living on the dental patina equal to the product of 400
milliards (in about a centigramme), x 100, viz., 40 trillions.
To these figures is to be added the huge mass of germs and

AND CONTENTS OF THE MOUTH. 307

elements spread in the saliva, of which a third part may be con-
sidered to be formed of microbes : ut tota aqua vivere videatur, as,
in his time, Leeuwenhoek wrote. The quantity of saliva which
continually moistens the mouth is not less than eight or ten
grammes ; therefore, we have three more grammes of germs and
elements, bringing the total up to 120 trillions.

But we will not further trouble the reader by calculating the
other germs and elements lodged on the tongue, in the mucus of
the mouth and pharynx, and in the nasal cavities ; from which it
would result that the figures given above are not at all exaggerated.

It is to be noted that we started with an average of 25 milliards
of bacteria per centigramme ; a figure twelve times under the cal-
culations of Naegeli — i.e., 30 milliards per milligramme, which
would make the mass of germs and elements of nose and mouth
upwards of 2 or j quadrilliojis.

Besides, we must consider that Leptothrix lodges, as we have
demonstrated, even in the mouth of domestic animals. Now, the
mucus, saliva, breath, urine, faeces of these animals, jointly with
those of men, constitute, in their whole, an immense preserve. I
am led to believe that a great many germs and elements of Lepto-
thrix pass into the faecal matters alive. There is also incalculable
diffusion in the air, waters, and soil, especially in populous towns.
What wonder, then, that Perroncito has found such a large number
of bacteria in the dust of the streets ? We may, rather, contend
that such a dissemination of buccal microbes constitutes a sort of
cloud, which hardly permits external germs to penetrate.

But let us return to the dissemination of Leptothrix in the
internal organs of the human economy.

With regard to the digestive passages, the number of elements
carried there by the saliva must be fabulous, considering that in
the smallest drop myriads of them are to be found. Nor is it
presumable that their descent into the stomach should prove
inactive.

The view that they are partakers in the transformation of ali-
ments is not new ; it goes as far back as Hallier, who considered
them necessary to the transformation, especially of starchy sub-
stances, not only in the stomach, but even in the mouth itself.*

* Richter, Monograph quoted in the Bibliography, Part I. , Section B 2.

308 BACTERIA IN THE SPUTA

Bechamp compared the transformation of saccharine in the pre-
sence of its i7iicrozymas with that of the faecula through diastasis.*
Warlcmann held the same action even for starch, and he conceived
that from the bacteria was secreted a true diastatic yeast, destined
to transform starch into glucose, although unapt to peptonise the
albumenoids.f But, later on, others recognised in buccal bacteria
even such a peptonising action, and Miller holds it to be equal to
that of the pepsine itself, even without the co-operation of acids.;}:

A considerable number of the same germs and elements of the
mouth, as well of the nose, is cast into the air-passages at every
breath, as the daily observation of the normal sputa shows (see
preceding Memoir). Those germs and elements thrive and multi-
ply in the mucus of the bronchi, trachea, and larynx, as the
fructification in the pulmonitic sputum, just described, shows ; it
is evidently a soil fit for the vegetation of Leptothrix.

Shingleton-Smith,§ in the quoted paper on Contagiwn Vivuffi,
considers, first, the property that the moistened mucous membrane
has of holding bacteria. It does not let them out with the breath,
but through the ciliary action of the epithelia, which throws them
out with the mucus. This happens with pathogenic bacteria, but,
a fortiori, it must be so with normal bacteria. The same author
quotes the experiments of Tyndal, who found the residual air from
the lungs absolutely free from particles which would reflect the
electric beam. He quotes as well the observations of Lister and
others, who maintained that there were no bacteria in the pus of
Empyena with Pneumothorax, the opening on the surface of
the lung being very small. This must indicate that the microbes

* Bechamp, Les Microzyuias et les Zymases, Arch, de Physiol., 1883.
The same, La Salive, la Slalozy/nase, et les Organismes Buccatix, etc. {vide
Bibliography), 1883.

tWarkmann, Untersuch. uber das diastatische Ferment der Bacterien
( Zeitschrift fnr Phys. Che?nie, Bd. vi., 1883J.

X See Bufalini, Of the Peptonising Action of Bacteria ( Giornale internaz.
delle Sc. Mediche, 1883). Miller, Ueher Gahrtingsvorgange im Verdauung-
stracttis iind die dabei betheiligten Spaltpilze {Dezit. ?n. IVoch., 1885, No, 49).
The same, Die A fihroorganismen der Mundhohle {see B\h\iogYa.phy), pp. 77 — 90,
where he specially deals with the fermentative action of buccal microbes upon
hydro-carbons, albumenoids, and fats.

%fournal of Microscopy and Natural Science, 1890, p. 34.

AND CONTENTS OF THE MOUTH. 309

are kept back by the mucus wetting the larger air-tubes, where the
protecting barrier of the epithelia exists ; but they cannot reach
the slender bronchi or alveoli where the epithelium is evanescent
or at all wanting. Thus, the microbes, having reached the border
of the smallest bronchi, by means of the ciliary action, they are
thrust back towards the superior passages, and carried at last, by
the sputum, into the normal or pathological mucus.

But if this happens in normal conditions, it cannot be so in
certain pathologic conditions, as in consumption, pleurisy, and
phthisis. The elements or parasitic germs, in these cases, not only
reach the most minute bronchi, but from there they diffuse them-
selves even to the remotest parts ; this may proceed from the
insufficiency of the ciliary action, or from an extraordinary con-
course of parasitic elements overcoming it, or from the microbes
along a denudated tract of mucous membrane.

Forster and Graefe* were the first to write upon the vegetation
of filaments or branching threads of Leptothrix on the conjunc-
tival or lachrymal ducts ; Bizozzero draws a specimen in PI. V.,
Fig. 52, of the quoted work. This has been reproduced in our
Fig. 6, d^ and it is natural to suppose that the relative germs origi-
nate from the nose.

If now, from the buccal and nasal microbes, we pass to con-
sider those of the external genito-urinary passages, we shall find
the same disseminations ; but with this difference, that they will not
be found so frequently and in such abundance. This depends
upon two reasons : — The first is the relative scarcity of parasitic
vegetation, especially on the balano-preputial mucus (compared
with that of the mouth and nose together) ; the second is the
want of a propelling force, sufiiciently vigorous and repeated,
capable of pushing, at least in normal conditions, the elements or
the germs of the parasites in the urethra or in the bladder. At
any rate, we must admit a penetration, on a small scale, by looking
at the epithelia of the inferior urinary passages. Such epithelia,
even in the most normal and freshly-discharged urine, are found
impregnated with bacteria to such a degree that they cannot be
attributed to consecutive pollution (viz., after the urine has been

* Forster, Arch, fur Ophtabii., t. xv., page 310. Graefe, Ueber Leptoth-
rix in den Thr<inenrohrchen,( Arch, cit., t. XVI., p. 324)*

310 BACTERIA IN THE SPUTA

passed) ; but they evidently denote their invasion in situ in the
bladder or the urethra. Of course, the invasion has happened by
a slow, progressive motion of the relative elements or germs,
either along the mucus coating, or from one epithelian scale to
another, and so forth.

In certain urine, round the small flakes or spires of mucus of
the male urethra, clods of Leptothrix are met, at times, so large as
to occupy the whole visual field of an objective (Nos. 7 or 8 of
Hartnack). Such clods are so closely similar to the young clods
of the patina dentaria, that the most experienced investigator
would be unable to distinguish one from another.

Lately, I observed a case of this kind in the urine of a patient
affected with chronic pyelitis, having already been subject to
several attacks of Blennorrhoea. I placed two of these small
flakes in a closed tube with a little of the urine, and for six days I
kept them adhering to the internal wall, wetting them gently once
or twice a day by inclining the tube. On the sixth day the mate-
rial of these small flakes, prepared and stained with gentian violet,
like the patina defitaria, exhibited exactly all the forms of Lep-
tothrix buccalis, with the exception of the productions by points
(perhaps spoiled in the preparation). Undoubtedly, it contained
countless bacilli, both comma and spindle-like, rather small, and
in brisk activity ; even a fair number of small ears was to be found
there. Briefly, all forms of bacteria and bacilli, chain-like fila-
ments, and bundles, described in Leptothrix buccalis (except the
Jodococcus vaginatus) were likewise there ; and the staining also
showed that not even the spirilla or spii-ochoeta^ mostly in motion,
were wanting.

Between these forms of Leptothrix and those of the mouth,
the only difference is that the filaments, bundles, and chains are
shorter and the spirilla extremely slender, but longer. In all other
particulars they were perfectly identical.*

* Our present remarks about the multiplicity of the microbes of Blennor-
rhoea and the presence of spirilla in urethral secretion have been confirmed by
the research of Legrain, On Blenorrhcea microbes. That author found in the flow
of gonorrhoea 12 different forms of cocci, 3 distinct forms of bacilli, and i spi-
rillicform: total, 16 forms of microbes ( Archiv f Dermatologie u. Syphilis,
1890). Stroganoff has recently dealt with the bacteria of the vagina and cervi-
cal canal. — {Modern Medicine a)id Bacteriological World, Oct., 1893, p. 258.)

AND CONTENTS OF THE MOUTH. 311

It would be useful to persevere in this kind of research, and I
propose to resume it on the first opportunity, in order to prove the
identity of Leptothrix buccalis with pr<^putialts, and then that of
bacteria and bacilli of the air-passages with those of the genito-
urinary organs.

We have an argument by analogy for the arrival of the elements
or germs of Leptothrix in the urethra, in the introduction of more
bulky germs, like those of superior fungi, probably of the genus
Penicillium, either in the urethra itself or in the bladder, of which
we have already given an instance in our article upon fungi of the
male urethra.

Naturally, the removal, insignificant in healthy conditions,
increases in the morbific ones, and that is the reason of the
gonococci in blennorrhoea ; but we have observed beforehand
that in blennogenous pus the most common form of bacteria is
not that of gonococci or curved diplococci of type g^ /, p (Fig. 2),
but that of common diplococci with round heads, sometimes
surrounded by a halo, either within or outside the epithelia or the
corpuscles of pus. I have already treated this argument in the
other paper upon a case of carcinoma of the bladder, in which
the urine showed a considerable number of curved diplococci or
gonococci, independently of any blennogenous contagion whatever.

In the Memoir on Whooping-cough, and in the first section
of this work, I have touched upon the presence of such curved
diplococci or gonococci in the sputa or saliva ; as well as upon the
singular discovery of true diplococci in a halo, morphologically
identical with the so-called pneumococci, in the spermatic fluid
recently discharged through illness.

I think that the surprise or incredulity which at first may have
been aroused from the present observations will cease, when it is
considered that the incentive of all these varied disseminations is
always the same, i.e., that the gonococcus as well as the pneumo-
coccus or the bacillus of Koch proceed, in great probability, from
small seeds of the same genus ; from the parasite that lives nor-
mally at the entrance to the digestive and air passages, at the
egress of the lachrymal as well as the genito-urinary passages.
What wonder, then, if the pneumococcus, towed, so to speak,
along the urethra, is found in the spermatic fluid ; and the gono-

312 BACTERIA IN THE SPUTA

coccus, in its turn, is found in sputa and saliva ; and that the
bacillus of Koch is met with, at times, even in the buccal epithelia
of a healthy man ?

For the rest, anyone is in a position to verify the exactness of
our observations upon these varied points." Now from the
exhibited facts we must infer that probably the same bacteria or
bacilli considered pathogenic (in the affections of the genito-
urinary or air passages) are, in reality, only so many disseminations
of germs or elements of buccal microbes or balano-proeputialis,
from which, morphologically, their varied types do not differ at
all ; or, at least, that, before admitting the existence of this or that
pathogenic bacterium in the above-mentioned passages, it is neces-
sary to demonstrate, with clear and conclusive proofs, that such
bacilli, declared pathogenic, are not derivations from the normal
preserve. And this objection does hold good, not only in the
hypothesis we have set up of the oneness, or duality at most, of
the parasitic species of the mouth, but even in the hypothesis now
prevailing of their plurality. We contend that the more species
there are in the nasal crypts or the cavities of the mouth, the
more difficult will it be to exclude their co-operation in generating
bacteria reputed pathogenic.

Everything, indeed, leads us to believe that this inexhaustible
preserve of normal microbes, placed by nature at the entrance of
the digestive and air passages, may have a defensive mission
against the intrusion of micro-organisms from without ; may, in
other words, constitute a true excluding vegetation ; a barrier to
the effect of preventing foreign germs penetrating and thriving in
the adjacent organs.

Nature has imparted to Leptothrix bicccalis such a power of
tenacious resistance to foreign agents that the elements of this
fungus upon the human teeth are not destroyed for ages, as it is

* We have lately noticed that our views are confirmed in an observation of
Bordoni Uffreduzzi and of Gradenigo, who found "in the pus of the left ear
(in a case of ottorhoea) numerous diplococci of biscuit shape, some isolated,
others joined in tetrahedrons, . partly free and partly contained in cellules, in
the whole similar to gonococci." The authors quoted maintain that the various
microbes of ottorhoea (in which the lanceolatus diplococcus predominates)
originate even from the saliva. SuW etiologia delPotite media. Archivio per le
scienze mediche, Vol. xiv., 1890, pages 276 and 278.

AND CONTENTS OF THE MOUTH. 313

proved from the dental tartar of the Egyptian mummies, in which
its filaments have been found intact by Zopf and Miller, by means
of dissolving the calcareous salts with acids/''

We would like to make further considerations upon certain
points of the present Bacteriological doctrines ; but, in order to
keep as far as possible within the clinical area to which our re-
searches are directed, we come to the final conclusion.

RECAPITULATION.

In summing up what has been exhibited in the Bacteriological
part of the preceding Memoir and the present one, we may con-
clude as follows : —

I. — Amidst all forms or types of bacteria or bacilli to be found
in the sputa, normal or pathological, there exist points of transi-
tion, manifesting their polymorphism, and the gradual passage from
one type to the other.

II. — Of the types in question, there is not one which cannot
be found even in the contents of the mouth, or in the nasal
mucus, and the balano-praeputialis patina. They do not morpho-
logically differ from each other ; therefore, it is generally main-
tained that the bacteria and bacilli found in sputa, in normal
conditions, are simply secondary disseminations of the buccal or
nasal microbes.

III. — But when we deal with bacteria, rightly or wrongly
reputed pathogenic — (as, for instance, the pneumococcus or the
bacillus of Koch) — it is another matter. We cannot grant their
buccal origin, setting up, instead, the hypothesis of their having a
specific origin from without.

Nevertheless, even these types cannot be morphologically dis
tinguished from their corresponding types of the contents of the
mouth or of the nasal mucus. We should have, at least, to
demonstrate, in a positive manner, that the former do not proceed
from the latter, although those same microbes are (like the other
buccal microbes) thrown by swarms into the air-passages. But that
demonstration has not been given ; nay, the only notion upheld

*Zopf, Die Spaltpilze, Breslau, 1883, page 80. Miller, Prehistoric Teeth
{Independ. Practitioner y 1884).

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. x

314 BACTERIA IN THE SPUTA

from their resisting the decolourising process has, in some instances,
been proved wrong.

IV. —Consequently, there only remain, in support of the spe-
cificity of such bacteria, the results, more or less controverted, of
the methods of culture and inoculation. We shall speak by-and-
by about the methods of culture, having already touched on those
of inoculation ; but leaving, for the present, that question on one
side, we wish to deny that the hypothesis of the speciality of
bacteria, found in pathological sputa, is at all supported by the
general clinical facts, or even by the daily microscopical obser-
vation of the sputa.

V. — The congeries of the buccal and nasal microbes, put
together, may be summed up to two hundred or three hundred
trillions of germs and elements in continual prolification. This
vegetation, either through its diffusion — (at least, in many species
of domestic animals) — or its constancy and abundance, assumes
the character of a true excluding vegetation, placed by nature at
the ingress of the digestive and air passages, to aid the former in
the digestion, and to defend the latter against the micro-organisms
of the external world. An identical vegetation adorns the egress
of the genito-urinary passages. Thence, it is not surprising if
bacteria reputed specific of the air-passages are found even in the
products of the genito-urinary passages, and vice versa : if, for
instance, incapsulated diplococci (pneumococci) are found in the
urethral mucus or in the spermatic fluid, and curved diplococci
{gonococci of Neisser, reputed specific forms of blennogenous virus)
are found, in their turn, in the sputa or in the middle ear.

VI. — Whatever may be the physiological importance of Lep-
tothrix buccalis, it results from our observations that its degree of
organisation is far superior to what has been reputed hitherto.
Leptothrix does not only live as bacterium, bacillus, or filament ;
but it possesses real organs of reproduction by which it would
resemble fungi and dioecious algce^ with distinct sexes upon different
filaments or individuals. Its fertile filaments are at times engrafted,
with two or three roots, upon clods or firm substrata, and end in a
fructification. The ears constituting these fructifications, as long (in
pulmonitic sputum) as i/6th of a milHmetre, are formed of many
very minute sporules (so much so that 400 milliards of them hardly

AND CONTENTS OF THE MOUTH. 315

would weigh a centigramme) ; and the small sporules, taking a
bright colour with aniline, are in some instances disposed in six
longitudinal series, making a total of 720 for each ear. They are
linked together and fastened to the stalk by means of an amor-
phous substance difficult to be coloured.* However, other fila-
ments, less numerous than these, at times multiply ; and lastly,
branching off, bear certain productions by pomts^ or pseudo inflo-
rescences, formed of spindle-like, snake-like, or comma bacilli
( Spirillu7ii sputigenum), destined from all appearance, through
their lively activity, to the function of conjugation. Finally, there
are gemmules in reserve, which (together with the multiplication
of the proper sporules) are destined to diffuse the species in the
unstable substrata or in the products and in the liquid secretions.

The fructification by ears can be reproduced, even in the sputa
and in certain small flakes of the urethral mucus.

VII. — Of the six primary species of fungi of the mouth, lately
described by Miller, there would, in fact, exist only one — the Lep-
tothrix buccalis of Robin {Leptothrix innominafa of Miller), or, at
most, a second one— the Spirillum {Spirochmte dentimn of Miller).
'I'he other four types would represent, if we are not mistaken, only
phases or disintegrated particles of the microphyte — viz., Bacillus
buccalis maximus and Leptothrix buccalis maxima., fragments of the
stumps that form the inferior layer of vegetation; \.\\q Jodococcus
vaginafus series of special sheaths of bacteria proceeding from
certain gemmules of reserve enclosed in the filaments ; the Spiril-
lum sputigenum (comma bacilli) with our spindle-like and serpen-
tine ; appendages detached from the pseudo inflorescences, and
probably male organs.

All these particles or articulations cut from the mother plant
(except the last — viz., copulative filaments) multiply by them-
selves, in various ways, according to the condition of the nutrient
substratum, in the liquid menstrua or on firm soil.

VIII. — The study of such vegetable forms, in the contents of
the mouth as well as in sputa (especially of the fructification by
ears\ requires special rules and care and proper optical means,

* Owing to the connecting of the sporules to the central stalk, by means of
peduncles or engrafting threads, visible with a new objective (i/25th in. objec-
tive). See former Note.

316 BACTERIA IN THE SPUTA

without which it would be difficult to verify the facts, even for the
most experienced investigators. The productions by points are
fairly well detected, even with the ordinary objectives ; but special
care must be taken in collecting and preparing the patina dentaria.

We do not know whether the specific oneness of the above
forms (by ears and by points) will be well received by competent
observers, as well as all the buccal microbes reunited in a single
plant. But, were even two or more of the vegetable species in
question, the successive dissemination of their germs and elements
in the air-passages would not at all be invalidated.

IX. — The most minute form of cocci, scattered or in a line,
found in the contents of the mouth, in the omonimous epithelia, or
in the sputa, are, in our opinion, nothing but sporules dropped from
the fructifications by ears^ being first disseminated in the mouth and
then thrown into the respiratory passages. The bacilli of Koch (we
are speaking of bead-like bacilH) might be only these same sporules
disposed in series, and thus germinating in the tubercular products
and elsewhere. Undoubtedly, the sporules, still attached to the
fructifications, or fallen near them, fix strongly the aniline colours ;
but it remains to be seen whether, in the sputa of consumptives,
their resistance to decolourising means is original or simply
acquired in the fresh nutrient substratum received from the tuber-
cular lesions. At any rate, that resistance is always relative, and is
of doubtful value in the diagnosis, and is sometimes inferior to
that of other bacteria^ as we have demonstrated before.

The forms of the bacilli of Koch being, on the contrary, in
small rods containing granules or vacuoles, with double staining
(gentian violet and solution of iodine) behave like the analogous
articulations of Leptothrix. But upon these and other not less
important points, about the clinical study of the tubercular sputa,
we shall have to deal on another occasion.

X. — However, if our observations on the morphology and
biology of Leptothrix are correct ; if all, or nearly all, forms of
bacteria and bacilli to be found in the sputa, are nothing but par.
tides or various organs of a single plant, everyone can see the
extent of the actual methods of culture (at least of the bacteria of
the air-passages).

And, to be sure, one person may identify or qualify a fungus

AND CONTENTS OF THE MOUTH. 317

on the ground of its fructification ; another, on the ground of the
form of cultures, immersed or creeping, of its single particles, or
the modifications brought about by these in the various nutrient
substrata. One bacterium or bacillus will fluidify gelatine or
elaborate certain principles (even poisons) in a manner totally
different from' another bacterium or bacillus, without, however,
considering the two forms as two organisms or different species,
when such forms are for us simply the result of organs or particles
of the same plant, destined to attain dissimilar aims, and which
may possess the most different qualities.

XI. — Under such conditions, the name of bacterium or bacil-
lus^can noj^longer be considered as synonymous of micro-organism.
We may speak of bacteria and bacilli, if by those names we mean
particles or^articulations detached from the mother plant ; and in
such "a case the generic noun of microbes may be even applied.
But^the word micro-organism applies to the whole microphyte of
which bacteria and bacilli are only single scattered particles, and
which do not constitute by themselves complete organisms, although
they'mostly possess the faculty of multiplying on their own account.
Such name does not suit at all the single particles, nor, of course,
the single^bacteria or bacilli.*

I cannot conclude this paper without a short statement.

Perhaps some of my views will appear too bold, but my only
intention was to submit them to the judgment of scientific observ-

* In ^"confirmation of our views, we shall quote the opinion of Klein, who
lately presented to the Royal Society of London the photographs of a culture of
the tubercular bacillus, which appeared with distinct branches Hke a mycelium
fungus. He inferred that at least a fezu schizophytes are really only forms of
development or transitory phases of superior organisms. The opinion of Dowdes-
well is even more expHcit. "It is clear " (writes the latter, on the subject of
comma bacilli) "that either these microbes are not normal schizophytes, or if so
they do not represent an independent group (as it has been observed by the last
writers on Bacteriology), but are sij?iple phases of evolution of some superior
organisms, or perhaps they are only simple organs of other organisms
{Lancet, 1890, Vol. I., loc. cit.,-^. 1422). Lately, Sheridan Delepine, studying
the development of bacteria in its culttires in interla^nellar films (between
the cover-glass and the slide) has come to that conclusion— viz. , of the branch-
ing off in many bacilli, by means of defined filaments (A New Method, Inter-
lamellar Films, of studying the development of Micro-Organisms, etc., in the
International Jotirnal of Microscopy y Nov., 1891, p. 343)*

318 BACTERIA IN THE SPUTA

ers. I shall only notice that my opposition to certain points of the
present Bacteriological doctrines is more apparent than real. I am
of opinion that, by pursuing the present method of specifying, in
the classification of bacteria, we must more and more multiply their
species to such an extent as to hinder the further progress of these
studies. On the other hand, should my observations be correct,
if the forms of bacteria of the air and genito-urinary passages are
reduced to a single species, or if, consequently, even the other very
varied types of bacteria (either not at all pathogenic or pathogenic
of other parts) might be gradually reduced to defined species of
micro-organisms, according to the natural phases of their full devel-
opment ; this work upon their arrangement and simplification may
aid in the researches of experimental pathology. In other words,
we shall be able to recognise the difference between the botanical
and the pathogenic entity of bacteria ; that two or more bacteria,
totally different in their own pathogenic action, may proceed from
a single micro-organism, and that a bacterium, not pathogenic,
may belong, in its turn^ to the same micro-organism from which a
pathogenic bacterium proceeds.

F. ViCENTINI,

Chieti,/une, i8go. Corresponding Member.

Bibliography.

I. — Arndt, Beobactungen an Spirochaete denticola (Arch, fiir

path. Anat. und Phys. und d. klinische Med. t. lxxiv. 1 880).
2. — Baume, Odontologische Forschungen, II. of the same, see

also the " Elements of Dentistry " (Lehrbuch der Zahn-

heilkunde, 3. Auflage, Leipzig, 1890).
3. — Beale, The Microscope in Medicine, London, 1878, p. 490.
4. — Bechamp. La salive la sialozymase et les organismes buccaux

chez I'homme (Archives de physiologic, 3 serie, I., 1883,

P- 47)-
2^ — Bizzozero, Manuale di Microscopia Clinica, Milan, 1882,

pp. 103—104 and p. 153.
6._Chevalier. L'etudiant micrographe, Traite theorique et

pratique du microscope, etc. Paris, 1882, pp. 393 — 94-

AND CONTENTS OF THE MOUTH. 319

7. — Cornil et Babes. Les bacteries et leur role dans I'anat. et
Thist. patholog. Paris, 1885, pp. 28 and 135.

8. Decker und Seifert. Ueber Mycosis leptothrica pharyngis
(Miinchen medicin. Wochenschrift. xxxv. 4., p. 67, 1888, and
Sitz. Ber. der physik. med. Ges. zu Wiirzburg, 2, p. 26.

9. — Dowdeswell. Note on the Morphology of the Cholera com-
ma bacillus (Lancet, 1890, Vol. I., pp. 1419 — 23).

— Evvart and Geddes, Life History of Spirillum (Proceedings
of the Royal Society, xxvii., 1878, p. 484.)

— Fliigge. I microorganismi ed etiologia delle mallattie
infettive. It. trans. Naples, 1889.

— Forster. Arch, fiir Ophtalm., xv., p. 318.

— Frey. Manuale di tecnica Microscopica. It. trans.

Naples, 1873, p. 278.
— Graefe. Ueber Leptothrix in der Tranenrohrchen (Arch, fiir

Ophtalm., t. XVI.).
— Hallier. Die pflanzlichen Parasiten, etc., Leipzig, 1866.
— Jacksch. Manuel de diagnostic des malad. inter, par les

methodes bacteriologiques, etc. (translated from the German),

Paris, 1888, pp. 50 — 57, and p. 71.
17. — Kiitzing. Linnaea, 1883.
18. — Leber. Quarterly Journal of Microscopical Science, 1874.

19. — Leber und Rottenstein. Untersuchungen iiber die Caries

der Zahne, Berlin, 1867.
20. — Lewis. A Memorandum on the Comma-shaped Bacillus

alleged to be the cause of Cholera (Lancet, 1884, Vol. II.,

P- 513).
21. — Miller. Der Einfluss der Mikroorganismen auf die Caries

der Menschlichen Zahne (Arch, fiir exp. Pathologic, xvi.,

1882).
22. Ueber einen Zahnspaltpilz, Leptothrix gigantea

(Berichte der Deutschen Botanischen Gesellschaft, Berlin,

1883, Heft 5, p. 221).
23. Zur Kenntniss der Bacterien der Mundhohle,

1884.

10

II

12
13

14

15
16

320 BACTERIA IN THE SPUTA

24. — Miller. Biological Studies on the Fungi of the Human
Mouth (Indep. Practitioner, 1885, pp. 227 — 83).

25. Beitrage zur Kenntniss der Mundpilze (Deutsche

Medicin. Wochenschrift, xiv. 30, 1888.
26. — Die Mikroorganismen der Mundhohle. Die

ortlichen und allgemeinen Erkrankungen, etc., Leipzig, 1889.

27. — Peroncito. I parassiti dell' uomo e degli animali utili.

Milan, 1882, p. 56.
28. II carbonchio, 1885.

29. — Rappin. Les bacteries de la bouche a I'etat normal et dans
la fievre typhoide. Paris, 1881.

30.' — Rasmussen. Ueber die Cultur von Mikroorganismen vom
Speichel gesunder Menschen, Kopenhagen, 1883.

31. — Richter. Die Neuern Kenntnisse von den krankmachenden
Schmarotzerpilzen, nebst phytophysiologischen Vorbegriffen
(Schmidt's Jahrbiicher, 1867, 135, pp. 81, loi, and 140).

32. — Robin. Des Vegetaux qui croissent sur les animaux vivants,
Paris, 1847, p. 42.

33. Histoire naturelle des vegetaux parassites qui

croissent sur Thomme et sur les animaux vivants, Paris, 1853.

34. — Sternberg. American Journal of Medic. Science, 1884 — 5.

35. — Vignal. Recherches sur les microorganismes de la bouche
(Arch, de physiol. norm, et pathol., 1886, n. 8).

36. — Zopf. Zur Morphologic der Spaltpflanzen, Leipzig, 1882.

37. Die Spaltpilze, Breslau, 1883, p. 80, etc.

38. — Zurn. Die Schmarotzer, etc., Part II., Weimar, 1887 — 89.

For the works of David and Billet, see note at the end of 3rd paragraph.

EXPLANATION OF PLATE VI. (see Afril, 1895).

FiC4. 4.

Other forms of Bacteria {Gentia)i Violet).

a. — Catenula of tyi^e jj, p (Fig. 1), incapsulated (Jodococcus vaginatus
of Miller, ?), from a sputum of Whooj^ing-cough, x 690.

b. — Diplococci with and without halo, and small cocci from the
patina deidaria mixed in the same heap. — &', Very minute diplococ-
ctis with halo from the patina dentaria mixed with saliva, x 1750.

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AND CONTENTS OF THE MOUTH. 321

c. — Dumb-bell bacteria, in couples, from the condensed nasal mucus,
in normal conditions, x 2500.

d. — Diplococci with halo (pneumococci), partly coloured, x 2500.

e. — Diplococci without halo, also partly coloured, from pulmonitic
sputum, X 2500.

/. — Pneumonocci with distinct halos of acuminated shape. /',
Another pale one, without halo, in increase, from a pulmonitic sputum,
X 1750.

g. — Large diplococcus in a halo, from pulmonitic sputum, x 2500.,

h. — Diplococci, without halo, in increase, containing internal gra-
nules, from pulmonitic sputum, x 2500.

i. — Large roundish diplococcus, with halo, surrounded by very
minute cocci. — i', Incapsulated catenula, formed of analogical diplococci,
from pulmonitic sputum, x 2500.

Fig. 5.

Other forms of Bacilli, from a to hj with gentian violet;

h\ ivith solution of iodine.

a. — Bacillus of three types, partly with internal gemmules, partly
clear, partly opaque, from sputum of influeitr.a, x 1250.

b. — Bacillus, partly opaque, partly clear, from saliva, x 1250.

c. — Bacillus of four types, from saliva, x 1250.

d. —Bacillus partially coloured, containing a transverse dumb-bell
bacterium (Bacillus hucccdis maximus of Miller, ?), from patina den-
taria, x 2500.

e. — Spindle-like bacillus, internally granulous, from sputum of
bronchitis. — e', Analogical bacilli, but cylindrical, from pulmonitic
sputum, X 1750.

/. — Two very slender bacilli, one mono-articulated, the other granu-
lous, from pulmonitic sputum, x 2500.

g. — Very slender bacillus with three knots, from the same sputum,
X 2500.

h. — Comma bacillus {Spirillum sputigenum of Miller) from pulmon-
itic sputum. — h', Serpentine bacillus, shaped like a spermatozoid
(coloured with solution of iodine), from the patina dentaria, x 2500.

Fig. 6.
Tufts of LeptothriXf in normal conditio)i, from Bizzozero, x 400.
a.— Bundles of filaments of Leptothrix.— 6, Articulated filaments,
c. Spirilla from patina dentaria.

rZ.— Tuft of Leptothrix from a concretion of the laclnymal bag.

Fig. 7.
Jodococcus vaginatus, Miller, x 1100.

322 BACTERIA IN THE SPUTA

Fig. 8.

Tuft of Leptothrix gigantea of a sheep in natural state, from Miller,

X 540.

Sj)., Spirillic filaments. F., Vibrio-filaments.

Fig. 9.

Roots, Swellings, and a few contracted fertile Threads of Leptothrix,
from the patina dentaria, x 850.

a. — Fragments of fertile filament, with two roots, in natural state
(haustoria, T).

h. — Fertile filament with three roots, and a swelling at the apex, in
natural state.

c. — Various forms of swelling at the apex, or small heads of young
filaments, with gentian violet.

d. — A large, somewhat woody filament, ending in a small chain
{Leptothrix buccalis maxima of Miller), with a contraction, from which
springs forth, at last, a slenderer fertile filament, with gentian violet.

Fig. 10.

Three fructifications by Ears, isolated, ivith gentian violet, from, the

patina dentaria, x 1250.

a, a. — Gemmules of reserve, within the stalk. — h, Intact sporules. —
h ', Residual sporules on the point of dropping from the ear.

c. — Ear grafted upon an older stalk, with knots.

d. — Ear grafted upon a younger stalk, .also with knots.

Fig. 11.

Tuft of Ears seen from above, with weak methyl violet, from

patina dentaria, x 1250.

Fig. 12.

Tuft of Ears seen in profile with weak f uchsine, from
patina dentaria, x 850.

Fig. 13.

Two Ears jutting out from a tiny island of materia alba, with
unacidulated solution of iodine, x 1250.

Fig. 14.

Productions by points (pseudo inflorescences), in natural state,

from patina dentaria.

a. — Branched pseudo-inflorescence, bearing small spindle-like bacilli
(male organs, ?), x 690.

b. — Isolated pseudo inflorescence, bearing analogical bacilli, x 690.

c. — Fragment of pseudo inflorescence, bearing spindle-like and
comma bacilli together (male organs, ?), x 690.

AND CONTENTS OF THE MOUTH. 323

d. — A dropped spindle-like bacillus, more enlarged, in quick motion
(Bacillus tremidus of J\iii>ijiu), x 1250.

Fig. 15.

Articulations and comma bacilli, with vacuoles, in apparent conjugation,
with unacidulated solution of iodine, from patina dentaria, x 2500.

Fig. 16.

Specimen of fructification by ears, filling up two visual fields
(coloured for two hours with gentian violet) from a very slender layer
of pulmonitic sputum, on the seventh day after the emission, x 850
and X 2500.

^.— A principal tuft. B. — A part of it drawn down to the
bottom from the pressure of the cover-glass, x 850. (This specimen
is erroneously marked Fig. 14 in the Plate.)

a. — Denudated Stalk, containing gemmules of reserve, x 850. —
a'y A part of it more enlarged, after a long saturation with glycerine,
with a trace of knot, x 2500.

b. — A long ear, mostly scattered, x 850.

c. — A broken ear, with clear section, x 850.

d, e. — Cumuli of sporules dropped from the adjacent ears, x 850.

/, g. — Points of two ears bent down from the pressure of the cover-
glass, X 850.

N.B. — Other fragments of ears were seen scattered about the
visual fields, around the specimen here delineated.

Saturn's Rings. —It has long been the accepted theory that
Saturn's rings consist of swarms of minute satellites crowded
together, but hitherto the evidence in support of this view has
been chiefly of a negative character, it having been proved by
mathematicians that the rings could not maintain their shape if
they were solid or fluid masses. A recent telegram from Pitts-
burgh announces that Prof. Keeler, of the Alleghany Observatory,
has proved from spectroscopic observations that the rings are
actually formed of satellites which do not all revolve at the same
rate, thus affording an interesting confirmation of the present
theory.

[ 824 ]

^be flDicroecopee of 1894.

DURING the past year considerable activity has been shown
by opticians in the manufacture of new forms of micro-
scopes ; indeed, we cannot remember any recent year in
which so many radical innovations have been adopted. Of course,
it is needless to say that that which is novel may not always be
good j but we venture to predict, regarding the new microscopes
and apparatus of last year which are both novel and good, that,
in popular parlance, they have come to stay, and as with certain
articles of universal consumption, no microscopist will be complete
without some of them. Another further source of congratulation
is that most of the instruments and apparatus in question are
within the reach of those of moderate means, and we are afraid
that that includes the majority of us.

Messrs. J. Swift & Son's Four-Legged Microscope.

The first instrument to which we would direct attention is
Messrs. Swift's four-legged tripod. One by one our cherished
ideals are being exploded, and now Messrs. Swift have killed ano-
ther by proving that a tripod may have four legs.

The microscope referred to (Figs, i and 2) has a diagonal rack
and pinion coarse adjustment, the fine adjustment being by micro-
meter screw ; at the back of the fine adjustment is a small milled-
head screw, by means of which any wear in the adjustment may
be taken up. The length of the body-tube from the ocular to
the nose-piece is 6 inches, and can be extended to 9 inches by
means of the draw-tube, which has a millimetre graduation. The
stage, of the horse-shoe shape, is provided with spring clips, or a
movable object-stage can be attached. I'he sub-stage can be had
in two forms, one being an ordinary fitting taking the condenser,
the other being the regular rack-and-pinion sub-stage. The body
of the instrument is supported on an horse-shoe platform, from
which the four legs spring ; the two front legs are fixed, but the
hind legs are pivoted to the platform. This arrangement of pivot-
ing the hind legs enables the microscope to adapt itself to any
uneven surface, thus keeping the instrument very steady ; it also
reduces the likelihood of the instrument being upset by any lateral

THE MICROSCOPES OF 1894.

325

Fig. I.

326

THE MICROSCOPES OF 1894.

THE MICROSCOPES OF 1894.

327

Fig. 3.

328

THE MICROSCOPES OF 1894.

movement to a minimum, getting rid of the only difficulty which
the small tripod form of foot is open to.

Fig. 2 shows the instrument with the hind legs turned up pre-
paratory to being put away ; it will be seen that there is another
advantage in this form in that it takes up less room in packing, as
the legs fit close to the pillar of the microscope.

Messrs. Swift's Three-Legged Microscope.

Previous to bringing out their four-legged form just referred to,
these makers produced this form of microscope (Fig. 3). With
the exception of the foot, the previous description is applicable to
this stand. The illustration shows the microscope in an horizontal
position, as used in photo-micrography. It will now be seen that
the horse-shoe platform in this and the preceding stand is extremely
serviceable, as it allows the pillar of the instrument to rest firmly
upon it, thus rendering the stand very rigid.

Messrs. Swift's Mechanical Stage.

This stage is simply unique, and came as a surprise to most
microscopists. It is the first time, we believe, that friction wheels
have been used for microscopical apparatus. The figure will
illustrate the apparatus in question better than any description. It
will be seen that the object-stage runs in grooves let into the side

Fig. 4.
of the horse-shoe stage. The slide, which rests on the stage of
the stand, is pressed by a wheel at the end of a powerful spring
against two small wheels on the inner edge of the object-stage.
Transverse motion is imparted to the slide by a turning milled

THE MICROSCOPES OF 1894.

329

head attached to a rod, which acts on two screw-heads, or rather
two endless screws, turning the wheels in question. The move-
ment in this direction is over i^ inches. The longitudinal move-
ment is by a screw, which runs in grooves on the outer
edge of the main stage. We believe that Messrs. Swift have
since placed the milled heads of the two movements on the
same side, so that an observer needs only to use one hand to the
stage, leaving him free to use "his other hand to manipulate the
adjustments. They have also further improved this stage by
placing the two wheels closer together, thus giving a wider trans-
verse motion — ?>., two inches.

Messrs. Ross & Co/s Eclipse Microscope.
When a simple idea is brought forward, we often feel inclined
to kick ourselves for not having thought of it before. Messrs.
Ross and Co.'s form of stand with the ring foot is a case in point.
It can be seen at a glance how steady this form of stand is, the
wonder being that it has not been thought of previously. But,
however, better late than never.

Fig- 5-

Fig. 6.

International Journal of Microscopy and Natural Science.
Third Series. Vol. V.

330

THE MICROSCOPES OF 1894.

Figs. 5 and 6 show the two simplest forms of this class of
microscope ; Fig. 5 being a rigid stand with a sliding coarse
adjustment, the fine adjustment being by micrometer screw. The
body tube is of the Continental tube-length (160 mm.), extending
by means of the draw-tube to 200 mm. (8 inches). The eye-
pieces are also of the Continental size. The makers call especial
attention to the manner in which the fine adjustment is capped,
thus preserving it from disturbance or injury by dust. Fig. 6 shows
the stand inclined ; it will be seen that the instrument is provided
with a knee-joint below the stage. The pillar is so arranged that it
can be rotated on its base, reversing the position of the stand, and
thus securing the stability of the instrument. When the instru-
ment is used vertically, it will be seen that the centre of gravity is
so placed that there is an equal steadiness in every direction.

Fig. 7.

Messrs. Ross have adapted the ring foot to a petrological
microscope (Fig. 7). This stand has a revolving circular stage
graded to 360°. The analyser, which can be drawn out when not
needed, is fitted to the lower end of the body-tube, in which there

THE MICROSCOPES OF 1894.

331

is also a slot, cut at the angle of 45^, for the insertion of the quartz
wedge. The polariser is pivoted to swing in and out of the field ;
it has a circle divided into eight and clicked at o^ and 180^ to
indicate where the nicols are crossed. The eyepiece is furnished
with crossed webs.

Fig. 8.

332

THE MICROSCOPES OF 1894.

Fig. 8 shows the highest class of the " Eclipse " stand, made
especially for bacteriological and other high-power work. The
adjustments are the same as in the preceding forms and the body-
tube is graded to millimetres. The stage is of horse-shoe form,
thus allowing free access to the sub-stage when focussing. The
sub-stage, which has centering screws, is carried on a triangular
bar attached to one side of the stage-plate ; the coarse adjust-
ment is effected by a spiral movement in the body of the sub-stage ;
the fine adjustment is by a milled head at the bottom of the
sub-stage bar ; the bar being at the side of the stage allows of the
sub-stage being flung in or out of position as required. The
triple nose-piece is so arranged that the objectives adapted to them
all focus in the same plane. The tail-piece carrying the double
mirror is slotted, and can be swung round to allow of the mirror
being used for super-stage illumination.

Leitz' Mechanical Stage.

This stage requires no description, as our illustration (Fig. 9)
shows everything that is needed. By means of a clamping screw,
it can readily be fixed to the stand of the microscope. The slide
is easily retained in position by a jointed curved arm. The finders
are so placed that markings can quickly be found.

Fig. 9.

Fig. lo.

334 THE MICROSCOPES OF 1894.

Leitz' Microscope.

In the January number of this Journal (page io6) for last
year, we called attention to the fact that at last one of the con-
tinental makers had adopted the tripod form of foot. Conti-
nental microscopists have to thank Herr E. Leitz, of Wetzlar,
for this improvement in their instruments. By the courtesy of
Messrs. C. Baker, we are enabled to give an illustration (Fig. lo)
of the stand in question. The only feature that we need point
out in this instrument is the sub-stage, which has an excentric rack-
and-pinion movement, and can also be moved in or out of position
as required. A horse-shoe stage can be supplied instead of the
circular one as depicted.

Watson & Son's "Grrand Model Van Heurck" Microscope.

This instrument (Fig. ii), which we have reserved till last, as
all the preceding forms are of the student's or low-price class, fully
answers up to its title ; it is a superb microscope. The stand is
mounted on a massive tripod foot, which has a spread of lo inches
in each direction ; when in an horizontal position, the instrument
has a lo-inch optical centre. The coarse adjustment is by rack-
and-pinion. The fine adjustment is by a finely threaded screw,
which bears on the end of a powerful lever ; this adjustment was
first adopted by Zentmayer, of Philadelphia, but after a short time
was found to work unsteadily ; to Messrs. Watson belongs the
credit of rectifying the error in the design and in practically making
the adjustment their own : it is now one of the most exquisitely
delicate and reliable forms of fine adjustment. Rack-and-pinion
and sliding movements are also attached to the draw-tube. The
stage, which has rectangular rack-and-pinion movements, is pro-
vided with finders, and can be completely rotated when required.
The sub-stage has centring screws, a coarse adjustment by rack-
and-pinion, and a fine adjustment by micrometer screw.

In microscopy it is often said that, given a good instrument, it
all depends on the man at the other end. We can now say, Here
is a good instrument ; now bring your man.

Fig. II.

[ 336 ]

flDicro0copicaI ZTecbniquc

Compiled by W.H.B.

The Best Method of Sharpening a Microtome Knife.*— Dr.

Lotsy thinks that Moll's method of sharpening microtome knives
is the best, as " it allows one to put the knife in good shape inside
of a few minutes for any section he wants to cut. Before using
this method, any concavity of the knife-blade must first be taken
away. Dr. Moll uses a plate of polished glass, which is fixed in a
piece of wood, and two different powders, viz. — Vienna chalk and
diamantine. A paste is made of one of these powders and put
upon the glass ; then the knife is simply moved backwards and
forwards upon the glass over the paste. By means of the Vienna
chalk you can polish your knife in a very few minutes. The dia-
mantine allows you to put a sharp edge on it, but does not give a
polished surface, but rather a rough one. Now, when you have a
knife which is highly polished, you can cut a section of, say, 5^
perfectly well ; but if you try to cut with it a section of i to 2^,
you will not succeed at all ; your sections will become compressed
and wrinkled, and you can do nothing with them. On the other
hand, if you try to cut a section of 5^ with a knife having a rough
surface, your section rolls up. This rolling up of a section has
been represented to be a fault in the paraffin, but that is not the
case. We must adapt the knife to every thickness of section we
wish to cut. Starting out with a certain knife, if your section
curls up, the proper thing to do is to polish your knife with Vienna
chalk, and your section for that thickness will not curl up. any
more. If your section becomes too much compressed, your knife
should be rubbed over the diamantine and the polished surface
taken away, when the sections will be cut without compression."

Preservation of some Marine Animals.t— Mr. W. A. Reden-
baugh says that while spending a few weeks at the U.S. Fish
Commission Laboratory at Wood's Hole, Mass., he obtained some
interesting results with Epsom salts in the preservation of many
marine invertebrates. "The method of application requires

*. Johns Hopkhis Hospital Bulletin, v., pp. 136 — 7.
\ American Xaturalist, XXix., 1895, pp. 399 — 401.

MICROSCOPICAL TECHNIQUE. 337

modification in individual cases, but a few experiments will usually
enable one to obtain the desired results. . , Complete stupifica-
tion of the organism must be produced, so that when it is removed
to a killing fluid no contraction will take place. Care should be
exercised, however, not to carry on the process too slowly, as
maceration may ensue.

Coekf iterates. — The most beautiful results were obtained with
sea-anemones, which ordinarily are so difficult to preserve in a
well expanded condition. These were allowed to expand in a dish
with as little water as possible. Then crystals of magnesium
sulphate were placed in the bottom of the dish and allowed to
dissolve slowly until a saturated solution was obtained. The
process of dissolving may be hastened, if necessary, by stirring up
the water gently from time to time with a pipette. Several hours
were required to completely stupefy large specimens. When nar-
cotisation was complete, a few crystals placed in the mouth of the
sea-anemone had no effect ; but if the process had not gone far
enough, the lips of the animal would slowly spread open, and then
would follow sometimes a violent contraction of the whole animal.
This method was tried upon Metridium marginatum.^ Sagartia
leucolena, and Halocampa produda with excellent results, the ten-
tacles remaining perfectly expanded after the animals had been
transferred to Perenyi's fluid, picro-sulphuric acid, or formalin.
The same method applied to Astrangea, Scyphisto?na, and various
hydroids did not give as good results as those obtained with the
sea-anemones. The polyps were not equally afl'ected, so that only
portions of the colonies were perfectly expanded. A large
Physalia treated in this way was preserved in 4 per cent, formalin,
with all the tentacles and polyps fully extended.

Echinoderms., — Star-fishes and sea-urchins were killed with the
ambulacral feet and pedicellaria well extended, by placing them
upon the aboral surface for a short time in a saturated solution of
Epsom salts, and then transferring them to 4 per cent, formalin.
The epidermis of the star-fishes, however, was rendered soft, and
was subsequently easily rubbed ofl", but this was probably due to
the formalin.

Specimens of Synapta were readily preserved without any
constriction by very slowly and intermittently adding to the water,

338 MICROSCOPICAL TECHNIQUE.

in which they had been allowed to expand, a saturated solution of
MgSO^ (Epsom salts).

Verj7ies. — Most annelids, when placed in saturated solution of
Epsom salts, in a very short time became perfectly limp, and were
easily extended upon a glass plate and treated with a fixing
reagent. Bala?ioglossus, when taken soon after being collected,
was preserved in this manner in nearly a perfect state. It was
necessary, however, to keep it in position between the edges of
two glass slides when the fixing fluid was applied. Good results
were obtained with Cirratulus^ Amphitrite^ Nereis^ R/iy?icobolus,
Clymenella, and Phascolosoma. Fhascolosonia, in most cases, was
killed with tentacles protruded. Nemertean worms when trans-
ferred to a killing fluid before being completely narcotised, some-
times protruded their probosces.

Ascidiaiis. — Molgida and Cynthia were readily killed with
siphons open after ansesthetisation with magnesium sulphate. In
this case it is best to add the saturated solution of sulphate
intermittently with a pipette.

Ctenophores. — After considerable experimentation, a method for
preserving these delicate creatures in a nearly life-like appearance
was devised. Formalin alone in solutions of varying strength had
been tried without success. It was found necessary to treat the
animals with some hardening re-agent before placing them in the
formalin, and the following method seems to be the most success-
ful:— To a solution of equal parts of 2 per cent, formalin and
Perenyi's fluid was added enough common salt (NaCl) to increase
the density of the mixture to that of sea-water — /.(?., until a Cteno-
phore placed in it barely floated. This adjustment of the density
of the surrounding medium prevented the Ctenophores from
collapsing of their own weight. After remaining for about half-an-
hour in this fluid, they were transferred to 4 per cent, formalin, the
density of which had been increased by the addition of either
Epsom salts or common salt, so that the Ctenophores again barely
floated. Epsom salts is probably better than common salt for
increasing the density of the fluid. Some specimens which were
preserved in formalin -I- NaCl began to shrink after a few days ;
while some {M?7e>niopsis) which have been preserved for nearly six
months in formalin + MgSO^ are still in excellent condition.

MICROSCOPICAL TECHNIQUE. 339

After the Ctenophores have been properly preserved, precau-
tion must be taken in transporting them, for they are easily torn to
pieces. If they are placed in bottles filled with fluid of the proper
density and the cork so inserted as to leave no air-bubbles, this
danger is reduced to a minimum."

Preservation of Sea-Weeds.^— Dr. J. P. Lotsy recommends the
following method of preserving specimens of Floridece, which
prevents swelling of the cell-walls or contraction of the protoplasm,
and preserves the chromatophores uninjured. The specimen is
first laid in a i per cent, solution of chrome-alum in sea-water,
and kept there for a period varying from one to twenty-four hours,
according to the size and texture of the species. The chrome-alum
is then completely washed out, and the specimen placed in a
mixture of 5 ccm. of 96 per cent, alcohol in 100 ccm. water, and
vigorously stirred. The amount of alcohol is then increased by
increments of 5 ccm. every quarter of an hour until it amounts to
50 ccm. The specimen is then removed, and placed in a mixture
of 25 per cent, alcohol in distilled water, and the quantity of
alcohol again increased in the same way till it amounts to 50 ccm.
alcohol to 100 ccm. of water. The same process is again repeated
with 50, 60, 70, 80, and 90 per cent, solutions of alcohol in dis-
tilled water, the specimens being finally preserved in the last.

Staining and Fixing Diatoms. t— Dr. P. Miquel finds the
staining reagent best adapted for demonstrating the gelatinous
envelope of diatoms to be an aqueous or boric solution of methylin-
blue, which is not taken up so readily by the gelatinous stipe.
The same reagent, especially in a slightly ammoniacal solution,
may be used for demonstrating the nucleus, which is stained blue,
while other substances contained in the cell take from it a dark
blue violet stain. For fixing, the author uses a solution of 65 gr.
corrosive sublimate and 15 gr. sodium chloride in 100 ccm. of
water.

^ Bot. CentralbL, LX. , vide Journ. R.M.S., 1895. P- ^S^-
tZ^ Diatoniiste, 11., 1894, vide Journ. R.M.S., 1895, P- ^27.

[ 340 ]

Laboratory Guide for the Bacteriologist. By Langdon
Frothingham, M.D.V. 8vo, pp. 6i, with 2 plates. (London: Henry Kemp-
ton. 1895.) Price 4/- net.

This is a most useful book of Bacteriological Technique, giving full instruc-
tions for the Preparation of Specimens, Staining Methods, Preparation of
Nutrient Media, and of Embedding Tissues for Cutting Sections. Each alter-
nate page is left blank for MS. notes, etc.

Object Lessons in Botany from Forest, Field, Wayside, and
Garden. Vols. I. and II. By Edward Snelgrove, B.A. Cr. Svo, pp. viii. —
109 and xii. — 297. (London : Jarrold and Son. 1895.) Price 2/6 and 3/6.

Two very capital books. Vol. I. is intended to meet the requirements of
Standards i and 2, and Vol.* II. for Standards 3, 4, and 5. The first is
thoroughly elementary and treats of subjects easily understood by the youngest
children, as apples, oranges, plums, garden vegetables, etc. The lessons in
Vol. II. are intended for children from nine to eleven years of age, and are
therefore restricted to those subjects of botany which lie within the scope of
their capacities. It contains 100 lessons, divided into the following sections : —
I., Leaves, Stems, and Roots; II., flowers; III., Fruits and Seeds; IV.,
Classification. Both books are thoroughly illustrated.

Laboratory Exercises in Botany. By Edson S. Basten,

A.M. Svo, pp. 540. (Philadelphia, U.S.A. : W. B. Saunders. 1895.)

A fine work, designed especially for the use of colleges and schools, in which
Botany is taught by Laboratory methods. It aims to inculcate in the student,
by the study of properly selected examples, a knowledge of the elementary
principles of botany, to develop his observing faculties, to stimulate in him the
spirit of investigation, and to lead him to take delight in this beautiful science.
The book is divided into two parts:— Part I., Organography, which deals
with the grosser structure of flowering plants ; and Part II., Vegetable His-
tology, or the microscopic structure of plants. It is illustrated with seven
figures in the text and 87 full-page plates from original drawings, comprising
upwards of 250 figures.

Across the Common after Wild Flowers. By Uncle Matt.

Down the Lane and Back in Search of Wild Flowers. By
Uncle Matt.

A Stroll in a Marsh in Search of Wild Flowers. By Uncle
Matt.

Around a Cornfield in a Ramble after Wild Flowers. By

Uncle Matt.

Through the Copse : Another Ramble after Wild Flowers.
By Uncle Matt.

Cr. Svo, each about 100 pages. (London: T. Nelson & Son. 1S95.) 1/6.

Five charming little books, by M. C. Cooke, M.A. , LL.D.. which will be
read with interest by every intelligent boy or girl of twelve years of age, giving
instruction in the structure and phenomena of plants. Besides a coloured illus-
tration on the cover, each volume contains a beautifully coloured plate, and
some 25 or 30 other illustrations.

REVIEWS. 341

Wayside and Woodland Blossoms : A Pocket Guide to
British Wild Flowers for the Country Rambler. By Edward Step. lanio,
pp. v'ii. — 173. (London: F. Warne and Co. 1895.) Price 7/6.

A most useful book for the country rambler. It contains 128 coloured
plates, giWng figures of 156 species, 22 full-page illustrations, and clearly
written descriptions of 400 species of plants. Persons taking country walks
and who are unacquainted with botany will find this book a welcome pocket
companion.

Die Naturlichen Pflanzenfamilien. By A. Engler and
K. Prantl. Nos. 113 — 116. (London: Williams and Norgate. Leipzig
W. Engelmann. )

These four numbers contain the conclusion of the Guttiferae, by A. Engler
the Dipterocarpaceae, by D. Brandis and E. Gilg ; Ancistrocladacese, by E
Gilg ; Elatinacese and Frankeniacese, by F. Niedenz ; Borraginaceae (con
eluded), by M. Giirke ; Verbenaceoe, by Briquet ; Bignoniacese (concluded)
by K. Schumann ; Pedaliaceae and Martyniacege, by O. Stapf ; Globulariaceae
by R. V. Wettstein ; and Acanthaceae, by G. Lindau. These four numbers
contain 75 illustrations, composed of 673 figures.

A Handbook to the Carnivora. Part I., Cats, Civets, and
Mungooses. By Richard Lydekker, B.A., F.R.S. Cr. 8vo, pp. vdii. — 312.
(London: W. H. Allen and Co. 1895.) Price 6/-

This volume of Allen^s NaHiralisf s Library is devoted in a great measure
to the family Felid^, followed by the various genera of the family Viverid.^.
Attention is also given to extinct Carnivora. There are 32 coloured plates in
the volume.

British Fresh-Water Fishes. By the Rev. W. Houghton,
M.A., F. L.S. Second edition. Roy. 8vo, pp. xxviii. — 231. (Hull & York:
A. Brown & Sons. London : Simpkin, Marshall, & Co. 1895.) Price 10/6.

This very handsome volume treats of the natural history of the various
species of fishes that are known to occur in the rivers, lakes, and ponds of the
British Isles, a description and an accurate engraving of each being given.
Sixty-five species of fishes are described and illustrated. There are besides
twenty-four prettily tinted plates of river scenery. The anatomy of the fish is
exhaustively described in the preface.

A Manual for the Study of Insects. By John Henry
Comstock and Anna Botsford Comstock. 8vo, pp. x. — 701. (Ithaca, N.V. ,
U.S.A. : The Comstock Publishing Co. 1895.) $3 net or $4-09 post free.

This is a handsomely got up volume, in which the authors have endeav-
oured to give to entomologists a handbook, by means of which the names and
relative affinities of insects may be determined in some such way as plants are
classified by the aid of the well-known manuals of botany. They have taken
much pains to render easy the classification of specimens ; groups of insects
have been fully characterised, and much space given to accounts of the habits
and transformations of the forms described. Special attention is given to wing
veins of insects. There are one coloured and five plain plates and nearly 800
wood-cut illustrations.

Practical Microscopy. By G. E. Davis, F.R.M.S., F.I.C.,

etc. etc. 8vo, pp. viii. — 436. (London: W. H. Allen and Co. 1895.)

This is a third edition of this well-known work on the microscope, and
contains much information which will prove useful to the microscopist.

342 REVIEWS.

The Theory of Light. By Thomas Preston, M.A. (Dub.).
Second edition. 8vo, pp. xyii. — 574. (London: Macmillan and Co. 1895.)
Price 15/- net.

At the present time there are many text-books on light-. The majority of
them fall short of the requirements of those who wish to know how far investi-
gation has been carried, or in what direction it remains to be pursued, and which
of these are the most urgent and most likely to be attacked with success. The
author's aim in this book is to furnish the student with an accurate and con-
nected account of the most important optical researches from the earliest times
up to the most recent date. Although a large portion of the book will be found
suited to the reading of junior students, yet it will be found sufficiently full to
meet the requirements of those who desire a more special acquaintance with the
subject. This second edition has been thoroughly revised and more than 100
new pages added. There are about 250 wood-cut illustrations in the text.

The Eye in its Relation to Health. By Chalmer Prentice,
M.D., Chicago. Svo, pp. 214. (Bristol: John Wright and Co. London:
Simpkin, Marshall, and Co. 1895.) Price 6/6.

Many of the opinions advanced by the author are evidently original, and
some are even of a surprising nature ; nevertheless, the general tenour of the
book is scientific, and will doubtless repay a careful perusal.

Murche's Science Readers. Books i, 2, 3. By Vincent T.

Murche. Cr. Svo, pp. 127, 128, 176. (London: Macmillan and Co. 1895.)
Price i/-, i/-, 1/4.

Three very interesting books of Object Lessons in Elementary Science,
dealing in a simple way with the commonest properties of bodies ; the nature,
growth, and structure of plants in general ; and some of the leading types of
the anima' creation. Each book is nicely illustrated.

Lessons in Elementary Physics. By Balfour Stewart, M.A.,
LL.D., F.R.S. Fscap. 8vo, pp. xii.— 475. (London: Macmillan and Co.
1895.) Price 4/6.

A new edition of this work, in which many additions have been made, is
now before us. It brings before the student, in an elementary manner, the
most important of those laws which regulate the phenomena of nature. It
treats of Laws of Motion ; The Forces of Nature ; Energy ; Sound ; Heat ;
Radiant Energy; Electrical Separation; Magnetism, etc. There are 157
illustrations.

An Introduction to the Science and Practice of Photography.
By Chapman Jones, F.I.C, F.CS., etc. Third edition. Cr. 8vo, pp. 326.
(London: Iliffe and Son. 1895.) Price 2/6.

In this work the various cameras, lenses, etc. , are fully described, as are also
the numerous processes. Owing to the rapid advances made in the science of
photography, several new chapters have been added, and others carefully
revised. The formula for solutions are given in both the English and metric
systems.

Nature in Acadie. By H. K. Swann. Cr. Svo, pp. viii. —
74. (London : John Bale and Sons, Oxford House, Great Titchtield Street.
1895.) Price 3/6.

We have here very pleasingly told a narrative of a Nature-lover's first
voyage westward, with an attempt at the word-picturing of what he saw during
his sojourn in Nova Scotia^ or, as he poetically calls it, Acadia.

REVIEWS. 343

The Story of Primitive Man. By Edward Clodd. Fscap.

8vo, pp. 206. (London: George Newnes. 1895.) Price i/-

In this little book we have told in pleasant language — I. — The place of
Man in the Earth's Life-History ; IL — The place of Man in ihe Earth's Time-
history ; III. — The Ancient Stone Age ; IV. — The Newer Stone Age ; and
V. — The Age of Metals. There are a number of illustrations, principally
relating to the Stone Age.

Short Studies in Nature Knowledge : An Introduction to
the Science of Physiography. By William Gee. Cr. Svo. pp. xiv. — 313.
(London: Macmillan and Co. 1895.) Price 3/6.

A thoroughly interesting little book, which, whilst making the reader
acquainted with some phases of the natural world, may also serve as a reader,
and companion to the text-books used in the upper forms at schools, etc.
There are 117 illustrations.

A New English Dictionary on Historical Principles.
Edited by Dr. James A. H. Murray. Vol. IV., Fanged — Fee. By Henry
Bradley, Hon. M.A. Oxon. (Oxford: The Clarendon Press. London: H.
Frowde. April, 1895.) Price 2/6.

We have received the April part of this great work. This section, which
covers the words between Fanged and Fee, contains 897 main words, 179
combinations explained under these, and 187 subordinate words, making a
total of 1263.

The Standard Dictionary of the English Language. By

Isaac K. Funk, D.D., Editor-in-Chief; Francis A. March, LL.D., L. H.D..
Consulting Editor ; Daniel S. Gregory, Managing Editor ; J. D. Champlin,
M.A., A. E. Bostwick, Ph.D., and R. Johnson, Ph.D., LL.D., Associate
Editors. 4to, pp. xx. — 2318. (London and New York : Funk and Wagnalls
Co. 1895.)

We have the greatest pleasure in introducing this grand work to the notice
of our readers. It embodies many new principles in I^exicography and contains
5,000 illustrations made expressly for the work, besides a number of full-sized
coloured and plain plates; 301,865 Vocabulary Terms. Two hundred and forty-
seven editors and specialists and 500 readers for quotations were engaged on it,
and we are told nearly five years were required to complete this work in. Where
the whole work is excellent, it appears useless to mention any special portion.

We wish, however, to point to a few of the special features of this work.
Whilst all the trades and arts have been searched for new terms, in Electricity
alone something like 4,000 new terms have been entered and described. As a
proof of the thoroughness in which the work has been carried out, we will
quote the explanatory note at Mythology : —

" Mythology among the Greeks took the form of idealisation of the beauti-
ful and esthetic (see list of gods at Olympian) ; as developed by the Romans,
it deified virility, war, and the principles of law and order (see list of gods at
Pantheon); in India, it deified the forces of tropical nature (see Aditi, Agni,
AsuRi, Brahma, Deva, Dyans, Indra, Kama, Krishna, Nirvana,
PuRANA, Siva, Tripitaka, Veda, Vishnu); in Eg}'pt, it centred about the
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[ 345 ]

apbanipteiu

By Lt.-Col. L. Blathwayt, F.L.S., F.E.S.
Plate XVI.

HAVE been interested, for some time past, in
studying the anatomy of Fleas, and having accu-
mulated a considerable amount of miscellaneous
information regarding them, I thought that these
fragmentary notes might be put togther, and woven
into something which, if of no great value from a
scientific point of view, would nevertheless prove
of some interest to the Members of the Bath
Microscopical Society, or, at all events, afford a
subject for discussion.

The title of my paper is " Aphaniptera,"* a name given by
Kirby from the Greek a(pavrig = inconspicuous, because, although
fleas have no wings, they were believed to possess rudiments of
wings. Macleay,t writing in 1819, says, "Vestiges of wings are
to be discovered even in the flea." And West wood, | in 1840,
adopting Kirby's order Aphaniptera, gives as characters — "Wings,
4 ; minute scaly plates applied to the sides of the body, those of
the metathorax being the largest. Huxley, in his Manual of
Invertebrated Animals (p. 367), says " the two hinder somites of the
thorax have lamellar appendages, which possibly represent wings " ;
and Nicholson, in his Manual of Zoology (p. 353), says of the
Aphaniptera, " wings rudimentary in the form of scales situated
on the mesothorax and metathorax." Theobald, in British Flies
(Vol. I., p. 21, now in course of publication), defines the Apha-
niptera as " parasitic, with scale-like rudimentary wings, the
metathoracic scales being the largest." Although I have taken as
the title of this paper the word "Aphaniptera," on account of its
very general adoption, I confess I prefer the term " Suctoria " of
De Geer, and for the following reason : / do not believe that fieas

* Kirby and Spence, Introduction to Entomology^ Vol. iv., p. 382.

t Macleay, Horce Entomologies^ p. 357.

X Modern Classification of Insects^ Vol. II., p. 488.

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. z

346 APHANIPTERA.

possess the least rudifuent of a wi?tg, and this I hope to explain
presently.

Westwood considered that the fleas formed a distinct order,
and he placed them between the Hemiptera and the Diptera,
being allied to the former in the structure of the mouth organs,
and to the latter in the metamorphoses they undergo ; and it is
now, I believe, generally considered that their true place is among
the two-winged flies. In the latest list of British Diptera, published
by Verrall in 1888, the order Aphaniptera is done away with, and
becomes a Family of Diptera, the PulicidcB.

Fleas have long been the subject of very various researches ;
they have been considered from philological, from historical, and
from satirical points of view ; they have been celebrated for their
strength and for their jumping powers, and still more frequently
cursed for their bloodthirsty proclivities. They have been educa-
ted, and proved of considerable pecuniary profit to their instructors.
But of their real structure, of their life-histories, and their correct
classification, a great deal more knowledge remains to be worked
out. For a long time it was thought that the fleas of difl"erent
animals belonged only to a single species,* and, consequently, that
the human flea was not different from that of a cat or a dog.
So accurate an observer as Gilbert White writes in his History of
Selborne (p. 200), '* The sand-martin is strangely annoyed with
fleas ; we have seen fleas, bed-fleas {Pulex ii-ritans)^ swarming at
the mouths of their holes, Hke bees on the stools of their hives."
I need scarcely tell you that the flea found on the sand-martin is
as distinct from Pulex irritans as a thrush is from a blackbird.
Daniel Scholten,t of Amsterdam, showed in 181 5, by his micro-
scopical observations, that fleas differ from each other; and in
1832, Duges, of Montpelier, investigated the distinctive marks of
the various species.

Regarding the number of species, however, we are stifl left in
the greatest uncertainty. WalkerJ describes fourteen, adopting the
names of the animals upon which, as a rule, they are found ; as
Pulex cants, P. felts, P. galli?ice, P. talpcE, and so forth. Verrall
in his list, though adding several new species not mentioned by

* t Van Beneden, Animal Parasites, p. 127.
X British Diptera, Vol. iii., p. i.

APHANIPTERA. 347

Walker, reduces the number to thirteen ; and Theobald also has
a total of thirteen, though he includes one omitted by Verrall.

Dale, in his History of Glanvilles IVooton, published in 1878,

writes (p. 290), "Although only fourteen species of the Aphanip-

tera have hitherto been described as British, thirty-eight have been

taken in this parish." And he then gives a list of names, as Pulex

furorts, on ferrets ; P. mtistelce, on weasels ; Ceratophyllus elon-

gatuSj on the great bat ; C. vespertiliojiis, on the common bat ;

C. musculi, on the common mouse ; C. muris, on the field mouse ;

and so on ; considering as a distinct species, and giving a specific

name to a flea if found on some animal from which he had not

before taken it. His descriptions are remarkably concise ; some

are as follows : — Ceratopsyllus merulce^ in blackbirds' nests, pallida

picio-fusca^ length i line ; C. arvetisis^ in skylarks' nests, picio-fusca

et obesa, length i line ; C. trochili^ in willow-wrens' nests, picio-fusca

et oblonga ; and so on. All these and a number of others I believe

to be merely Pulex avimn, varying a little in size and colour. The

colour of a flea, however, depends a good deal upon its age, and

also on the contents of the stomach ; while ^^obesa^^ was probably

the result of a plentiful meal, or that the capture was a female

containing eggs.

Before entering into an anatomical description of the flea, I
shall refer to it from an historical and from a literary point of view.
The earliest mention of a flea that I have come across occurs in
the Book of Samuel,* cir. B.C. 1060 : "for the King of Israel is
come out to seek a flea." But about seven hundred years later,
Aristotle (born B.C. 364), in his History of Animals, shows that
he knew the flea underwent a metamorphosis, for he noticed, not
only that it had distinct sexes, but also that they produced oKuAtiQ
utoaideiQ = egg-shaped worms. I suppose he must be here referring
to the pupa, which is egg shaped, for the larva is greatly elongated.
He did not, however, trace the changes of the insect far enough,
and fancied that the perfect insect was generated spontaneously in
the earth f ; and Isodorus, a Bishop of Seville, who lived about
the beginning of the seventh century^ stated that the Latin name
Pulex was derived ixovo. pulvis — dust, ^^ quasi pulveris filius '^ ;

* L Samuel xxvi. 20.
\ Class, of Ins., Vol. 11., p. 492.

348 APHANIPTERA.

but Skeat considers it a modification of the Sanscrit phi = to
jump, from which we have the Dutch vloo^ the German fioh^ and
EngUsh flea. Scahger thought that they were produced from
humours amongst the hairs of dogs. Dr. Thomas Mouffett, an
Enghsh physician of the time of Queen EUzabeth, who wrote a
very curious Latin treatise of Zoology,"^' held an opinion similar to
that of Aristotle. I have searched Pliny's Natural History^ but,
although the whole of his eleventh book is devoted to insects, I
can find no mention of the flea.

Latreille,t in his Natural History of Insects, says, "the Indians,
on account of their belief in metempsychosis, take the greatest
care of these creatures, as well as of all kinds of vermin that suck
human blood. At Surat a Hospital has been established for them,
some one being hired for the night who allows the creatures to
make a meal from him." He gives also an account of the per-
forming fleas which, in his time, were being exhibited in Paris.

In their Introduction to Entomology, Kirby and Spence| say,
" Aristophanes, in order to make the great and good Athenian
philosopher, Socrates, appear ridiculous, represents him as having
measured the leap of a flea." § I think, however, that the ridicule
was directed at the method of calculation, not at the calculation
itself. The account runs, " Socrates and Chserephon tried to
measure how many times its own length a flea jumped. They
took in wax the size of a flea's foot, then on the principle of ^'' ex
pede Herculem " calculated the length of its body. Having found
this, and measured the distance of the flea's jump from the hand
of Socrates to Chserephon, the problem was resolved by simple
multiplication.

A great deal has been written about the habits of fleas, but it
is difficult to say how much of this can be relied on. M. Defrance
wrote, " Small, shining black grains are nearly always found mixed
with the fleas' eggs, and these consist of dried blood. It is a
provision which the thoughtful mother flea has prepared at our
expense for the nourishment of its posterity. Figuier writes, ||

* Insectoruni sive minimorttm aninialium Theatruni.

t His. Nat., Vol. xiv., p. 404.

% Vol. II., p. 310.

%Nubes, Act. i., Sc. 2. \\Les Insectes, p. 33.

APHANIPTERA. 349

" There is something very remarkable about the manners of fleas ;
the mother flea disgorges into the mouth of the larva the blood
with which she is filled " ; and Van Beneden, in Vol. xix. of the
International Science Series, 1889, says, "The larvae of fleas live
only on what the full-grown insect brings them ; the mother flea
sucks for herself first, and then divides the spoil with her larvae."
The stories are copied from one book to another, but as the author
rarely or never informs us that he writes from personal observation,
I think these statements require confirmation. According to Van
Beneden it is probable that the dog flea is the intermediate host
of the tape-worm common to that animal.

The fleas are all comprised in the two families Sarchopsyllidce
and Futicidce. Passing over for the present the first of these, which
contains only a few species, and none of them being found in this
country, and adopting the classification in Verrall's list, we have in
Britain three genera — Fulex, Hystrichopsylla, and Typhlopsylla.

The common flea, P. irritans, is sometimes regarded as the
only species of the genus Fulex, and the rest are ranked under
other genera; but this seems rather in honour of man as being the
host of the first-named flea than from any real difference.

Fleas may be classed as follows : —

a. Eyes distinct — Genus Fulex (in Britain about seven species).
aa. Eyes wanting or rudimentary — Hystricopsylla (one species)

and Typhlopsylla (four species). The chief genus Fulex
can be sub-divided.

b. No spines on back or head — F. irritans (man).

bb. Spines on back only — Comb with 18 teeth: F. fasciatus
(rat), F. melts (badger), F. sciurorum (squirrel). Comb
24 to 26 teeth — F. avium (birds).

Under side of head with spines : 7 to 9 spines — F. serrati-
ceps (dog, cat) ; 2 spines on cheek — P. erinacet (hedge-
t^og) ; 5 to 6 on each cheek — F. goniocephalus (rabbit).

Eyes wanting Typhlopsylla : 3 spines on cheek —Assimilis
(mole).

The slides and photo-micrographs that I have brought to
illustrate this paper are chiefly of F. goniocephalus, which I found
in great numbers inside the ear of a rabbit. This species was

350 APHANIPTERA.

named goniocephalus by Taschenberg, on account of an angular
projection on the forehead, which, however, is not always very
apparent. It is probably the Ceratophyllns leporis of Curtis.

The mouth-organs of the flea consist of a pair of mandibles
with toothed edges, a tongue, an underlip with two palpi, which,
when joined, form a hollow tube in which the tongue lies ) their
structure is well shown in P. avium. In this the tongue has been
removed, and the mandibles are two long delicate bristles, which
lie close together at the top. They are so transparent that they
are difficult to photograph, and in the female of P. avium they are
scarcely visible ; they are the two faint lines on the left centre. In
P. g07iiocephalus^ on the other hand, the mandibles are large, strong
blades, doubly serrated along the edges. There are also two
maxillae, generally triangular plates, each with a four-jointed palpus.
Regarding the labial palpi, Westwood* says, "these are three-jointed.
Latreille described them as three-jointed ; Curtis described them
as four-jointed; while Dujes figured them as five-jointed. Theobald
says they are four-jointed ; while Taschenberg, whose descriptions
of fleas are by far the most accurate of any I have yet seen, says
they are four-jointed, and adds, " Bouche has quite wrongly des-
cribed them as five-jointed, and Kolenati has fallen into a similar
error." It is impossible to tell, by the examination of an entire
flea mounted in balsam, what is the real number of joints in these
labial palpi, though in the maxillary palpi the joints are distinct
enough. I did not try to decide the question until a few months
ago, and then I found it almost impossible to get any living fleas,
except goniocephalus from the rabbit, and aviu7n from poultry ; but
from these two species I found that in the latter they are five-
jointed, as described by Bouche, Dujes, and Kolenati ; while in
the former they are only two-jointed, a number of joints which, so
far as I am aware, has not been mentioned by anyone. In fact, I
suspect it to be the old story of the Chameleon, " You all are
right, you all are wrong," and that the naturalists who thus differ
have dissected and described different species of flea.

The eye, when present, lies generally about the centre of the
head, and is a simple ocellus ; sometimes; however, it is very near
the lower margin. Close behind it lies the antennae, in a kind of

* Class. Ins,

APHANIPTERA. 351

groove, and are sometimes more or less covered by a chitinous
plate. I shall return to the structure of the antennae later on.

The thorax consists of three distinct segments, each bearing a
pair of legs ; and each segment is composed of one dorsal plate
and two side-pieces or pleurae. There is a very small spiracle,
difficult to see, just at the posterior lower corner of the pleura of
the prothorax. Then holding a very similar position on the meso-
thorax there is the small, round scale, which has hitherto been
called a rudimentary wing, but which is really a spiracle. Then
at the back of the metathorax is the large flat scale, which is said
to represent the hind wing by all except Taschenberg, who, how-
ever, while denying that this is a rudimentary wing, asserts that it
is a portion of the metathorax. For my part I am inclined to
believe that it represents the first ventral plate.

There are eight clearly defined abdominal segments ; some
authors say nine and some ten ; but then they probably include
the genital plates. Each segment consists of one dorsal and one
ventral plate, the former bending over the back and down on each
side, and contains two spiracles, and usually bears one or more rows
of bristles. The first dorsal plate, however, is much smaller than
the others, and does not contain any spiracle, the missing spiracle
being situated quite at the top of the so-called rudimentary wing, or,
according to Taschenberg, metalhoracic appendage, or, as I think,
first ventral plate. The fact that it bears a spiracle, two rows of
stiff bristles, that there is no plate beneath it^ it alone forming a
covering for the soft parts of the body below, is quite conclusive
that it cannot be a wing. Taschenberg considers that the posses-
sion of bristles and a stigma prevent it being a ventral segment,
for, he says, " the other ventral segments have no spiracle and no
such bristles. But then, if this is the case, I ask, " What has
become of the first ventral segment ?" It would only tire you if I
went through all my reasons for my opinion ; but very likely after
all I may be wrong, and I shall certainly not forget the concluding
lines of the Chameleoft : —

" When next you talk of what you view.
Think others see as well as you :
Nor wonder when you find that none
Prefers your eyesight to his own."

352 APHANIPTERA.

In addition to the presence of eyes and combs, I have found
the following very useful distinctions in defining species : —

I. — The relative length of the joints of the tarsi.

2. — The number of joints in the labial palpi.

3. — The structure of the mandibles — in some a large, flat,
double-toothed saw ; in others a long delicate bristle.

4. — Their very various antennae.

Van Heurck, in his work on The Microscope^ published two
years ago, gives an illustration of the pygidium of a flea, and
states that it contains from thirty-two to thirty-eight areolae. As
the pygidium of P. goniocephalus contains only twenty-eight, 1
think it probable that this also may be of use as a specific distinc-
tion.

I now come to the antennae. The older naturalists quite over-
looked these, which, as a rule, lie hidden in grooves close behind
the eyes. Kirby and Spence, for instance, have a very good
drawing of the parts of a flea's mouth ; but, like many previous
observers, they do not appear to have noticed the real antennae,
but mistook the maxillary palpi for them, and consequently the
names they gave to the other parts of the mouth are inaccurate.
Latreille, also, although he overlooked the real antennas, appears
to have been in doubt, for he speaks of these maxillary palpi as
^^Antennce, potiiis palpi!' Louis Figuier, in one of his popular
works, published not more than twenty years ago, still states that
these palpi are the flea's antennae.*

Regarding the true antennae, Westwood writes : — " The
antennae are minute articulated organs, varying in form in the
different species, composed apparently of four joints, the third of
which is very minute, and forms the cup-shaped base of the ter-
minal joint, which in some species is furnished with numerous
transverse incisions, which have been considered by Curtis as so
many distinct articulations." There is, I think, no doubt that
Curtis was quite right, for in this photo they are plainly separate
joints. I do not think, however, that the so-called third cup-
shaped joint is a joint at all, but consider it as merely a thickening
of the top of the second joint, which forms a support for the base
of the third. To show how greatly these organs vary both in size

* Les Insecles, p. 30.

APHANIPTERA. 353

and structure, according to the species and even the sex of the
flea, I have prepared photographs of the antennae of J and $ of
Pulex avium, one of F. goiiiocephahcs, and one of P. erinacei, all
magnified to the same extent — viz., 200 diameters.

Many species of flea have a number of spines on the back of
the prothorax, forming a sort of comb, and some have similar
spines on the sides of the face. These combs have the teeth
always directed backwards, and must greatly assist the fleas in
maintaining their hold among the hairs of the animals they infest,
and the probability that this is their use is strengthened by the
fact that the human flea alone is entirely devoid of them.

At the extreme end of the flea's body is the pygidium, a circu-
lar plate with a division down the middle, in which are situated a
number of areolae, each containing several wedge-shaped eleva-
tions placed in a circle, and with a rather long hair or bristle
implanted in the centre. The spaces between these areolae appear
to be covered with small spines on the top of small tubercles.
These show rather indistinctly in F.goniocephahis, which is magnified
750 diameters, taken with ^-in. oil-immersion without ocular.
The addition of a projection ocular, which has increased the
magnification to 1,500 diameters, has, however, failed to disclose
any further detail. The pygidium of a flea is an excellent test to
judge of the defining power of an objective.

The second genus, Hysirichopsylla, contains only one British
species — the Pulex talpce. of Bouche, Ceraiophyllus talpce of Curtis,
regarding which, however, Dale says, writing in the Eiitomologisf s
Monthly Magazine, in June, 1890, "It is quite certain that Talpce
is a misnomer, as it is not found on the mole." As I have not
been successful in obtaining a specimen, I pass on to the third
genus, Typhlopsylla, which contains four or five species, some of
them infesting bats. One species, T. assiinilis, is very common
on the mole.

Not having as yet bred any fleas, I have no personal know-
ledge of their metamorphoses. It is said that each female lays
about a dozen eggs at a time. These are deposited in various
places, such as the cracks in boards, in carpets and rugs, on
the hairs of dogs and other animals, and in various other
places according to the species. These eggs soon hatch, and

354 APHANIPTERA.

from them come worm-like maggots. These larvae have no feet,
but the last segment has two strong curved hooks. In a fortnight
or less some species spin a silken cocoon. (It was this, I fancy,
which made Aristotle speak of them as " egg-shaped" worms.) In
some species the larvae are said to live through the winter and not
pupate until the spring. Certainly, during the past winter, I have
had the greatest difficulty in obtaining any fleas.

Regarding the parasites of fleas I know very little ; but only a
few days ago, on some fleas I took from a rat, I found some
minute white acari, which were to a wonderful degree tenacious
of life. I put the fleas into liquor potassae, which appeared to
kill them in about ten minutes ; but twenty-four hours later I found
an acarus walking about on the body of one of them to all appear-
ance none the worse ; the remaining acari had all disappeared.

I have not been able to find any record of fossil fleas. The
geographical distribution of fleas seems to be world-wide ; they
are found from the Arctic regions to the equator. Darwin, in the
Voyage of the Beagle^''' writes of the mountains near Coquimbo : —
" I enjoyed my night's rest here from a reason which will not be
fully appreciated in England ; namely, the absence of fleas. The
rooms in Coquimbo swarm with them ; but they will not live here
at the height of only three or four thousand feet." This, he
states, cannot be on account of the trifling diminution of tempera-
ture at that height. They occur just as plentifully in the mountain
chalets of Switzerland as in the warmer valleys.

Before bidding adieu to the fleas, I must just mention the
other family of Aphaniptera — the Sarcophsyllidce, of which fortu-
nately we have no representatives in this country.

According to Taschenberg there appear to be only two or
three species, but it contains the famous, or rather the infamous,
" Jigger " {Sarcopsylla penetrans)^ an American pest, especially
abundant in the West Indies and in the north of South America.
It is often called the sand-flea. The males and the immature
females are no worse than other fleas ; it is the impregnated female
which is the chief trouble. She burrows under the skin of animals,
in the feet or under the toe-nails of man. There her body swells
to the size of a pea under the pressure of the eggs within her,

* Voyage of Beagle^ p. 344.

APHANIPTERA. 355

which eggs are ready to hatch in about a week. In the meantime
the flea herself has undergone a marked change, the internal
organs being atrophied by the growth of the eggs.

According to some authorities, if the female is not extracted
mortification of the toe or foot may set in. The late Rev. J. G.
Wood disbelieved the stories of the injuries caused by the Chigoe.
He gives his brother as his authority, and his words are : — " A
great deal of rubbish has been written about the Chigoe. It is
true our friend is a great nuisance in his way, but in six years I
have never known, or ever heard, of anyone being much the worse
for the Chigoe, though I have seen some people too lazy to
extract them until their feet were full of their nests. . . There
is a slight itching, and then, if they are extracted with any reason-
able amount of care, the nest of eggs comes away all correct. If
it should be broken, which will happen sometimes, a pinch of snuff
is put into the hole, and there is an end of the matter.'"'' Other
authors, however, who had as good or better opportunities of
finding out the true state of the case, have come to a quite different
opinion. Until about twenty years ago the Jigger was believed to
be confined to America, and Mr. Newton, Vice-Consul at Loanda,
states that before 1872 the Jigger was not known on the West
Coast of Africa ; but in that year a ship, the Tho??ias Mitchell,
arrived from Rio Janeiro, the crew of which were suffering from
Jiggers. These were quickly communicated to the crews of the
boats and introduced on shore, and they have since gradually
spread along the coast. Mr. Newton says that he has seen many
natives without toes, and in a dreadful state from allowing the eggs
to remain and hatch and the wound to fester.

Walton, in his History of St. Domingo, records that a Capuchin
friar, desirous of settling the dispute as to what genus the Jigger
belonged, brought away with him from that island a colony of
these animals, which he permitted to establish themselves in one of
his feet ; but unfortunately for himself and for science, the foot
intrusted with the precious deposit mortified, was obliged to be
amputated, and, with all its inhabitants, committed to the waves.f

I think that more credit must be given to the affirmative than

* Insects Abroad, p. 772.
tKirby and Spence, Vol. I., p. 100.

356 APHANIPTERA.

to the negative evidence, and the Jigger be put down as one of
the worst of insect pests.

Although I shall be very glad if some other member of this
Society will take up this subject, I must point out that it has its
drawbacks. During the winter I could obtain very few specimens,
but with the arrival of the warm weather the fleas arrived, mostly
the dog-flea, by hand and by Parcel Post. I now look on any
unknown small box with considerable suspicion, and open it with
as much care as a policeman examining a box which he thinks
may contain an infernal machine.

Besides a number of slides, the following photographs were
shown to the members : —

Pulex in-itans^ man,

P. fasdatus, rat.

P. sciurorwn, squirrel.

P. avium, sand martin.

P. serraticeps, cat.

P. erinacet, hedgehog and dog.

P. goniocephahiSy rabbit.

Typhlopsylla assimilis, mole.

Ditto ditto turkey.

P. avium, $ , mouth organs. Mandibles like long fine bristles.

X lOO.

Ditto, Mandibles, labium, with 5-jointed palpi; Maxilla, with

palpus, X 100.
P. erinacei (from dog), mouth-organs complete, tongue serrated

as well as mandible, x 100.
P. goniocephalusy $, mandible serrated, x 200.
Ditto, antenna in groove behind eye, x 100.
Ditto, I St ventral plate, or rudimentary wing, showing spiracle,

X 50.
Ditto, one of the dorsal plates, x 50.
P. avium, portion of head with antennae, showing articulations,

X 200.
P. goniocephalus, $ , antenna, x 200.
P. avium, $ , portion of head with antenna, x 200.
P, erinacei, antenna, x 200.

Journal of Microscopy, 3 Ser. Vol.5. Plate 16.

X 200

Moul/v Organs &o. of FLeo^.

RELAXING INSECTS FOR CABINET. 357

P. gom'ocephalus, ?, pro-thor. comb with 15 teeth, x 100.

Ditto, maxilla, with 5 genal spines, x 100.

Ditto, pygidium, with last abdominal segment, x 100.

Ditto, ditto, showing hairs which spring from areolae, x 750.

Ditto, portion of pygidium, showing areolae, x 750.

Ditto, areolae of pygidium, x 1500.

EXPLANATION OF PLATE XVI.

Fig. 1. — Antenna of Flea from dog, Pulex erinacei.

2. — Pygidium of Pulex goniocephalus, showing hairs which spring
from areolae.

3. — Larva of Flea from Cat.

4. — Pulex avium, ^ . Portion of head, with antennae.

5. — Complete mouth-organs of Pulex erinacei, showing serrated
tongue as well as mandible, x 100.

6. — Serrated mandible of Pulex goniocephalus, x 200.

J)

))

IRelaying 3n0ect0 for Cabinet

By G. H. Bryan, M.A.

1HAVE not tried the effect of naphtha as recommended in the
extract from the E7itomologisf s Record, quoted on p. 226 of
this Journal, but I have tried shellac, and I have also tried
removing the insects from the setting board, both at the end of
twenty-four hours and after a few days or a week, and I can there-
fore state from experience that there is no surer way of rendering
valuable insects worthless as cabinet specimens. Shellac disfigures
the bases of the wings, and is at the same time no safeguard
against springing, and the only relaxed insects which I have had to
destroy in my collection on account of the wings having "sprung"
so hopelessly as to ruin them were some that I fixed with shellac
many years ago. There is no "royal road" to relaxing insects.

As far as my experience goes, I find the best plan is to pour a
layer of plaster of Paris into the bottom of a biscuit-tin and keep
the plaster well moistened, and place the insects over this. It is

358 RELAXING INSECTS FOR CABINET.

better to run the plaster into a separate tablet instead of pouring
it straight into the tin, as the tin is less likely to rust, being less
closely in contact with the plaster. For butterflies in envelopes
whose wings are folded, I stand a number of pins upright in rows
in the plaster just as it is setting, and stand each insect between
two pins. I have been more successful with plaster than with
sand, but a great deal depends on keeping the relaxing box at a
sufficiently warm temperature (yet not so hot as to soak the wings
with steam). A hot-water cistern is very good for this, but I have
even had recourse to a small spirit-lamp on emergency.

A little wet, if it condenses on the wings, can be absorbed with
blotting-paper, and the insects will stand a fair heat, which will
generally render them more pliable in a day than if they had been
kept in the cold for an indefinite length of time. A little care
about heating is of far more value than all the nostrums which
various writers recommend on the experience of setting half-a-
dozen insects. As regards preventing springing, if the insects have
been on the setting boards for a months one may begin to think of
taking them off. Three weeks is decidedly risky, unless the
boards are kept in a particularly warm, dry place — e.g.^ hanging on
a wall, with a kitchen chimney behind it. If on being placed in
the cabinet, the wings still show signs of springing upwards, they
may often be kept down with card braces transfixed with pins for
weeks until all tendency to spring has been cured.

Finally, if you do not wish to have your specimens disfigured
with unsightly rubs and gashes across the wings, such as are seen
in nine collections out of ten, you cannot be too particular about
the mounted setting needles used for drawing the wings into place.
Curved needles are particularly useful, as they enable the wings to
be moved forward into place from the underside, where the needle
has a better grip on account of the projecting veins, and rubs do
not show above. I have nearly thirty different kinds of setting
needles, each adopted to its own special purpose, some with only
i/32nd of an inch projecting beyond the wood, some with the eye
end projecting, besides a large number of curved ones. A "needle
holder," as used for dissecting purposes, is also invaluable. With-
out a good supply of setting needles ready at hand, a considerable
percentage of insects will be damaged in setting.

[ 359 ]

iSlucetione bearing on Specific Stability.

By Francis Galton, D.C.L., F.R.S.

[The following paper, which has just appeared in the Transactions of the Ento-
mological Society (1895, pp. 155 — 7), is, we think, of such importance
that we obtained the kind permission of Dr. Galton to reprint in this
Journal, in the hope that some of our readers may help to elucidate the
many problems connected with Specific Stability. Communications relat-
ing to the subject should be addressed to Dr. Galton, 42 Rutland Gate,
London, S.W.]

' '^T^HE questions are more especially addressed to those who

JL have had experience in breeding, but by no means to
breeders only ; nor are they addressed only to entomolo-
gists, being equally appropriate to the followers of every other
branch of Natural History.

" I should be grateful for replies relating to any species of
animal or plant, whether based on personal observation or referring
to such observations by others as are still scattered through the
wide range of periodical literature, not having yet found a place
in standard works.

" The questions are for information on the following subjects :

" (i) Instances of such strongly-marked peculiarities, whether
in form, in colour, or in habit, as have occasionally appeared in a
single or in a few individuals among a brood ; but no record is
wanted of monstrosities or of such other characteristics as are
clearly inconsistent with health and vigour.

" (2) Instances in which any one of the above peculiarities has
appeared in the broods of different parents. [In replying to this
question, it will be hardly worth while to record the sudden
appearance of either albinism or melanism, as both are well
known to be of frequent occurrence.]

" Note. — The question is not asked now whether such pecu-
liarities, or ' sports/ may be accounted for by atavism or other
hypothetical causes.

" (3) Instances in which any of this peculiarly characterised
individuals have transmitted their pecuUarities, hereditarily, to one
or more generations. Especial mention should be made whether
the peculiarity was in any way transmitted in all its original inten-

360 QUESTIONS BEARING ON SPECIFIC STABILITY.

sity, and numerical data would be particularly acceptable that
shows the frequency of its transmission {a) in an undiluted form,
{b) in one that was more or less diluted, and {c) of its non-trans-
mission in any perceptible degree.

** It is impossible to explain . . . the precise way in which
the derived facts would be utilised. An explanation that would be
sufficiently brief for the purpose could not be rendered intelligible
except to those few who are already familiar with the evidence,
and the technical treatment of it, by which the law of Regression
is established, and with the consequences and requirements of that
law. Regressiveness and Stability are contrasted conditions, and
neither of them can be fully understood apart from the other.

" I may as well take this opportunity of appending a list of my
various memoirs on these subjects. The most important of these
are Nos. i, 3, part of 6, 7, and 8, in the following list. Nos. i to
5 refer to regression only.

'^ List of Memoirs by the Author on Regression

AND Stability.

I. — 'Typical Laws of Heredity.' Journ. R. Institutto?t, 1877.

This was the first statement of the law of Regression, as

founded on a series of experiments on sweet peas.
2. — 'Presidential Address, Anthropol. Section, Brit. Assoc, 1885.

Here the law of Regression was confirmed by anthropologi-
cal observations.
3. — ' Regression towards Mediocrity in Family Stature,' Journ.

Afithrop. Inst.^ 1885. A revised and illustrated reprint of

No. 2.
4. — ' Family Likeness in Stature.' Froc, Roy. Soc, 1886.
5. — 'Family Likeness in Eye-Colour.' Proc. Roy. Soc, 1886.
6. — 'Natural Inheritance.' Macmillan and Co., 1889. This vol.

summarises the results of the previous work.
7. — 'Patterns in Thumb and Finger Marks, and the resemblance

of their classes to ordinary genera. R/ii/. Trans. Roy. Soc,

1891.
8. — 'Discontinuity in Evolution.' Mind, 1894. This is an article

on Mr. Bateson's volume."

[ 361 ]

®n tbe StuJ)^ of flDicio^jfungi.

By W. Thomson. Plate XVII.

THE study of fungi, while being regarded by many as perhaps
one of the most uninviting which the world of nature affords,
is, nevertheless, regarded by others as one of the most
fascinating of the many branches of Natural Science. One man
smites down with his stick every fungoid growth that appears
before him, whereas another man would almost as soon think of
smiting down a friend. If those of us, however, who are regard-
less of the fungi world were privileged to enter the sancticm sancto-
rum of some mycologist who has devoted years to the study and
collection of fungi, our indifference would be supplanted by deep
interest. As he displays the treasures of his collection, drawer
after drawer filled with boxes, and shelf after shelf laden with
bottles, all containing specimens, and describes with enthusiasm
some particular points in their life-history, or some exciting hunt he
had in quest of them, it will begin to dawn upon us that there
must be something in it after all. I have been in the rooms of a
certain mycologist (lately deceased), where every available resting
place was occupied either with specimens or with literature on the
subject, and where even the dining-table was literally covered, save
a small portion reserved at one end for its legitimate use, with
fragments of bark, broken pieces of branches, withered leaves, and
miscellaneous piles of specimens, which had just been brought
home for examination. In the midst of such disorder, however,
my friend was in his element. He seemed thoroughly possessed
with his favourite hobby, and dwelt with manifest pride upon his
specimens. He ate many of the species, talked continually about
them, and indeed appeared to live entirely for fungi.

If we had followed our friend into his happy hunting grounds,
we should have found him prowling about old stick-yards, creeping
along dry ditches, or laboriously examining one by one the fir
cones, leaves, or broken twigs, which covered the floor of some
plantation. Indeed, so enthusiastic and diligent was he that it
was often said that he had fungus on the brain ; but he heeded not

International Journal of Microscopy and Natural Science.
Third Series. Vol. V. aa

362 ON THE STUDY OF MICRO-FUNGI.

the remarks nor the opinions of those who, as he would say, knew
nothing about fungi. His perseverance was rewarded by the dis-
covery of many species which had not previously been found.
He was ever ready to have a chat with kindred spirits, and to try
to influence others to take an active interest in a study which had
afforded so much pleasure and enjoyment to himself No stranger
who visited his rooms and evinced any interest in the specimens
would depart without first having seen his collection of micro-
fungi, and more particularly his collection of those micro-fungi
which grow upon living plants, and we know that those who took
his advice to bestow a little attention on this comparatively neg-
lected study have received an ample reward for their trouble.

Now, it is to this latter-named branch of mycology that we wish
specially to draw attention in this paper, and we will try to show that
the domain of micro-fungi is not such an uninviting and desert
land as it might at first sight appear. The honey-bee finds in
the modest-looking clover more of the sweetness of which it is
in search than in the brilliantly painted foxglove ; and many
insects and animals find a more congenial abode on plants of a
very humble and unattractive character than on many of those
which are most highly esteemed by man. In the same way, there-
fore, as an insect may prefer to live upon a common nettle rather
than upon the Rose of Sharon, so there are men who, in making a
choice of some branch of study as their own speciality, prefer to
pass over the more prominent and fashionable fields of research,
and to settle down in a comparatively obscure corner. There is
doubtless a certain novelty and charm in a choice which leads one
out of the hard-beaten track, and away from the busy crowd of
observers, into a less-populated country, where there are yet many
things to be discovered.

Thomas Carlyle remarks that the Torch of Science has
been brandished and borne about with more or less effect for
5,000 years and upwards, and that " in these times not only the
Torch still burns, and perhaps more fiercely than ever ; but nnu-
merable Rushlights and Sulphur Matches kindled thereat are
also glancing in every direction, so that not the smallest cranny or
doghole in Nature or Art can remain unilluminated." Though
almost every cranny now obtains a share in the general illumina-

ON THE STUDY OF MICRO-FUNGI. 363

tion, still many of them are yet dim enough to render acceptable
the smallest light, and around the subject of our present study
there is still sufficient darkness to give our sulphur matches an
opportunity of letting their light be seen.

There is a certain fascination in poking about hedgebanks and
odd nooks and corners in search of these fungi, knowing that at
any moment some new specimen may present itself, or the missing
link in the life-history of some species be found. This opportu-
nity of turning up fresh soil without very much difficulty should
prove a strong recommendation to anyone who wishes to find out
something new. The study of micro-fungi should also commend
itself to those who desire to take up a subject which will require
the use of a microscope, for in it they will find that their favourite
instrument is in continual demand ; indeed, that it is an absolute
necessity.

It is, of course, a much pleasanter occupation to search for the
fungi which are parasitic upon the leaves and stems of living
plants than for those which are to be found only by grovelling
among rotting wood and decaying vegetation. A beginner may
probably experience some little difficulty at first in finding speci-
mens, and will be sure to overlook many which would be seen at
once by a more experienced eye. As the fungi are small and
many of them inconspicuous, they require to be very carefully
searched for, or else they will never be found at all. A hasty
observer may cover a great deal of ground in an afternoon's
excursion, but, in all probability, he will not secure half so many
specimens as the collector who travels no further than a stone's
throw from the starting-point, and who carries out the search in a
complete and exhaustive manner.

Most of the fungi we are considering grow on the under-
surface of leaves, and therefore^ until some experience has been
gained, a considerable amount of time will be spent in diligently
turning over the leaves without any specimens being found. Very
soon, however, the fungus-hunter will learn to recognise, from
certain signs — such as the sickly appearance of the plant, the dis-
coloration of the leaf, or the abnormal growth — those plants which
are most likely to have a fungus established upon them. Con-
tinual practice will soon develop a sharp eye for the most minute

364 ON THE STUDY OF MICRO-FUNGI.

growths, so that in course of time it will be found that even when
walking quickly along a road or over a field, the suspicious-like
appearance of a plant or a small coloured spot upon a leaf will
often arrest the attention of one who is familiar with such signs.

We remember that upon one occasion, when hastily cross-
ing a field, a slight yellow coloured spot on a leaf of the common
daisy was sufificient to cause a halt in order to see what was the
reason for the discoloration It turned out to be the Cluster Cup
Fungus (^cidium bellidis)^ and although a considerable search
was made, no more than three very small diseased leaves could be
found. This habit of always looking for diseased plants grows
upon one, so that no matter how beautiful the flowers and sur-
rounding vegetation may be, the eye is continually wandering
about in search of any sign which betokens the presence of a
fungus ; and, although it may sound strangely to the uninitiated,
the joy is much greater when the plant is found to be attacked by
one of these parasites than when it is in the full vigour of health.

It is not always easy, by a cursory examination, to distinguish
those marks which are caused by fungi from those which are due
to insects or the natural decay of the tissues of the plant ; indeed,
until the microscope has been brought to bear upon them, it is
sometimes almost impossible to settle the question with certainty.
The common dock by the wayside is a prominent offender in this
respect, as the leaves are very frequently marked by coloured
spots, which prove an abundant source of disappointment, until
the collector is rendered wary and taught not to expect too much
from them. Mistakes of this nature, however, become fewer as
the observer becomes more familiar with his subject.

The majority of the species must be looked for on the under-
surface of the leaves, and there will be found to be a great diver-
sity, not only as regards the microscopical appearance of the
different spores, but also as regards the appearance which they
present to the naked eye, both in colour and in the manner of
their growth on the host plant. The beautiful cluster cups, to
which we shall refer more particularly further on, will, on some
plants, be seen in clusters, on others in circles, and on others
scattered about in no apparent order or running down the leaf-
stem, as is frequently seen on the Violet ; while on the Willow

ON THE STUDY OF MICRO-FUNGI. 365

Herb, for instance, they will cover the whole under surface of the
leaf. In some cases the fungi appear as black, brown, orange, or
reddish patches or spots, and in other cases as a fine black or
golden powder peppered over the leaf. Then we have species
which adorn the backs of leaves like spores on the fronds of ferns
species which give the plants the appearance of having been well
sooted, and species which invest the stems and leaves with a
covering as though enamelled with a coat of white paint. We
shall find fungi which follow the lines of venation, and fungi which
spread themselves quite independently. On the Dog's Mercury
we shall see the parasite ( Uredo confluents) slowly destroying the
leaves on which it is established ; and on the Nettle we shall often
notice how the Cluster Cup (Vadium urticce) irritates the
tissues and causes the stem to swell and to become much bent
and distorted.

Of course, there are species — such as Puccitiia calthce on the
Marsh Marigold — which are rarely met with, and species — such as
the jEcidium on the Coltsfoot — which are very common. In one
locality a certain fungus may be exceedingly plentiful, whereas in
another place, although the host plant is common enough, it may
not be possible to find a single specimen of it. These parasites
make a host of all manner of trees and plants — the oak tree, the
rose bush, and the tender moschatel alike forming a habitation for
them. But it does not by any means follow, that because a fungus
has been recorded as growing upon the young leaves of the oak in
one part of the country, that therefore we are likely to find speci-
mens of it wherever we find an oak tree \ nor should it always be
taken for granted that because we have found a certain fungus in
one locality, that all the host plants of the same species which are
growing even comparatively near at hand will also be infected with
the fungus. The case of the ^cidium on the Daisy before men-
tioned illustrates this, as, although there were plenty of the same
plants growing around the spot where the three diseased leaves
were found, yet all of them appeared to be perfectly free from the
fungus.

What causes affect the distribution of the fungus and lead to its
appearance in one place and not in another, and how it comes to
pass that the spores which grow upon, say, the Primrose will not

366 ON THE STUDY OF MICRO-FUNGI.

develop upon, say, the Dandelion nor on any other of the many
plants which may be flourishing around, will probably become
clearer when we consider their life-history.

In commencing to make a collection of these minute forms, it
would undoubtedly be a great advantage to have the advice of
someone already acquainted with the locality, who could point out
where particular specimens might be looked for, and which were
the most prolific places in the district ; but, though sueh assistance
might often save a good deal of needless searching, it might, on
the other hand, not be very conducive to the acquirement of much
fresh information as to their habitats, nor leave very much scope
for the discovery of new specimens. Neither does it seem an
altogether satisfactory plan for the collector to make out a list of
host plants from a book, and then, searching out these plants, to
examine them for the parasite which has already been recorded as
occurring upon them. This method would no doubt expedite the
making of a collection, but it is manifest that it would curtail the
chances of adding to the number of host plants. It appears to
me that the best plan is to go forth unbiassed towards any partic-
ular plants or district, and to search first one plant and then
another, totally regardless as to whether a fungus has ever been
found upon them or not. By so doing we should, at any rate, put
ourselves into the path of original observations, and have an oppor-
tunity of being successful.

The specimens when collected should be pressed, and then
either affixed to paper or preserved in an envelope, care of course
being taken to keep a record of the place where obtained, and of
the date of finding. When the name of the host plant has been
noted, and the spores of the fungus examined with the microscope,
we shall very probably be able to make out the species without
much trouble, but when this is done we should not let our interest
in it cease, for each fungus has a life history of its own, and it
ought to be our duty to learn something regarding it. There is
certainly considerable pleasure to be derived from collecting the
specimens and ascertaining the species ; but if we content our-
selves merely with gathering together a collection, we do not differ
very much from the man who stocks his library shelves with books
and chooses to remain in ignorance as to what is written within

ON THE STUDY OF MICRO-FUNGI. 367

them. If this man were to try to arrange his library, he might
easily put the parts of a three volume work in different places in
his bookcase, instead of keejMng them together as one work, and
this is exactly what was done with these fungi, for many of them
were classified as being distinct species until their life histories
were studied, and it was shown that one species might have several
stages, and that, though the spores in each stage were different,
they required to be reckoned only as one species.

If we briefly trace the growth of one of these fungi and follow
it through the different stages, we shall, perhaps, be enabled more
easily to understand what is here referred to, and for this purpose
we propose to take as a sort of typical example the species which
grows upon the Nipplewort {Lapsana communis). We have chosen
this species for our illustration because we have found it, in addi-
tion to being one of the commonest, to be one of the earliest to
appear after the winter is over, and because the host plant can so
readily be obtained for purposes of experiment by those who wish
to try to cultivate the fungus. If we were to examine one of these
plants which ultimately produces a fungus, we should at first see
no evidence of the presence of the fungus, although it had already
taken up a lodgment in the tissues of the plant ; but though
nothing is outwardly visible, the parasite is nevertheless gradually
gaining a footing. Within the tissues there is growing and deve-
loping that part of the fungus, the mycelium, which in due season
will make itself manifest and produce the spores which appear on
the surface of the leaf. This mycelium consists of an "assemblage
of hyaline tubes^ which ramify chiefly between the plant-cells, and
these mycelial tubes branch off and unite with one another until
a perfect network is formed within the tissues.

When we remember that the fungus is a parasite, it is scarcely
necessary to say that consequently it lives at the expense of the
plant upon which it has taken up its abode, and it will at once be
evident to us that the mycelium is for the purpose of supplying
the fungus with the necessary nutrition by abstracting the material
which the plant has elaborated for its own use. The fungus
cannot, therefore, be considered as a very welcome guest, seeing
that the host must, nolens vole?is, provide it with sustenance quite
independent of any question of comfort or convenience. When

368 ON THE STUDY OF MICRO-FUNGI.

the mycelium has developed to a certain extent, the areas in which
it is present will be distinguished by the green of the leaf being
changed into a reddish or purplish colour. Not only is the chlo-
rophyll affected, but, as might be expected from the presence of
such a growth in the tissues, the parts will very probably soon
become swollen and bulged out, giving a deformed appearance to
the leaf.

When the mycelium is sufficiently far advanced, large numbers
of very fine hyphse or branches are given off from it. These
hyphse grow towards the epidermis, and their apices incline to a
central point, so as ultimately to form a flask-shaped body, termed
a spermogonium, immediately beneath the epidermis. The apex
of this body, spermogonium, then pierces the cuticle and becomes
visible on the surface of the leaf as a minute elevation. From
the ends of the hyphse, which project into the interior of the sper-
mogonium, are budded off a large quantity of very small, round
bodies, to which the name spermatia has been given. These
spermatia continue to increase in numbers till the whole cavity is
filled with them.

The hyphse which form the apex of the spermogonium then
separate and make, as it were, a mouth to the flask, thus providing
a free passage from the interior of the body. Through this
passage the spermatia, which are held together by a sticky sub-
stance, gradually ooze out to the surface of the leaf, and it is
stated that this propulsion of the contents is due to the action of
moisture in causing the gelatinous matter which binds the sper-
matia to swell. Plate XVII., Fig. i, shows a section of a spermo-
gonium. When the spermatia are placed in water containing
sugar, it has been found that they multiply almost in the same
manner as the well-known yeast spores. Many experiments have
been made by those who make a special study of these objects
with a view of ascertaining definite information regarding their
functions, and of finding out what part they play in the life of the
fungus ; but it does not appear that any of the theories which
have been advanced can be considered as having given a satisfac-
tory explanation.

The exit from the spermogonium is surrounded by the ends of
the hyphse, and they are supposed to act as a sort of hedge to

ON THE STUDY OF MICRO-FUNGI. 369

prevent the spermatia from being washed off. Whilst the viscid
substance in which they are embedded restricts their distribution
by preventing the wind from blowing them away, it has been
observed, on the other hand, that this investing material forms an
attraction for insects on account of the saccharine substance it
contains, and that when the insects depart after their feast of good
things they carry away, adhering to their feet, small portions of
this viscid substance, with, of course, the spermatia that are
enclosed in it. The spermogonia are very small, and appear
immediately before, or at the same time, as the spores about to be
mentioned, and, unless they are specially looked for, may very
easily pass unnoticed ; but if a beginner experiences any difficulty
in making out the spermogonia to his satisfaction, he will have no
trouble in recognising the development we are now to consider :
the aecidiospore stage.

As soon as ever the Nipplewort begins to put forth its young
leaves in spring, just so soon should we look out for the first stage
of the fungus. We have found it bursting through the leaf as
early as the nth February, but it will, as a rule, be most plentiful
about the month of April. By, say, the end of May, the first
stage will have disappeared entirely. If, then, we examine the
plants almost as soon as they appear above the ground, we shall,
if the mycelium is present, very soon see evidence of its existence
in the change of colour which begins to take place in the affected
areas. Before long there will appear, shining through the epi-
dermis, the yellow spots which show that the aecidium is being
formed beneath, and if we look carefully we shall perhaps be able
to find the spermogonia. In a short time the ?ecidium will burst
through, and we shall have the pleasure of looking upon a number
of Uttle cups filled with yellow spores.

We say pleasure, because a cluster of these cups, each fringed
with a margin of white teeth and brimming over with the golden
grains, is a sight which never fails to please, and, especially when
examined with a pocket-lens or low power, it forms an object of
great beauty. When the fungus is further advanced, it will be
noticed that the peridia, or cups, are abundant on both sides of
the leaves, and, as it has been stated already that the aecidium on
many plants appears only on the under surface, it will be noted
that ^cidium lapsaitcB is an exception in that respect.

370 ON THE STUDY OF MICRO-FUNGI.

The peridia grow in very irregular patches or clusters, and
often cover more or less all the leaves of an infected plant.
Indeed, this stage of the fungus affects the host plant much more
prominently than do the succeeding stages, and it is consequently
more easily found. These cups arise from the same mycelium
which produced the spermogonia, and are formed at centres where
the mycelial tubes have become branched and gathered into small,
round masses. These almost spherical bodies increase in size,
and, when about ready to break through the cuticle, it is found
that in the centre of each there has been developed a number
of upright hyphae or branches of the mycelium, each supporting a
column of spores, and that this forest of hyphae and multitude of
spores are enclosed within a covering of barren cells. The spores
become filled with a yellow colouring matter, those at the tops of
the column coming to maturity first, but the enveloping cells —
though in other respects similar to the cells from which the spores
have been formed — remain empty.

As soon as the aecidiospores — that is, the spores of the
Vadium — are ripe, the epidermis is ruptured and the fungus
presents itself to the world. The covering of barren cells gives
way and becomes curved backwards around the margin, thus
turning the body into a small cup, and laying bare the aecidio-
spores which have been produced within. PI. XVII. , Fig. 2,
represents a magnified section of an aecidium, and makes clear its
general structure. The spores at the surface of the cups being
ripe, and having been detached from the tube in which they were
developed, are at the mercy of every wind that blows, and it will
easily be observed how very readily they are scattered abroad.
On examination with the microscope, these aecidiospores will be
seen to be smooth and nearly spherical. In diameter they are
about 18 micromiUimetres (one micromillimetre= i/25,4ooths of
an inch). As we look into one of these cups and see the quan-
tity of spores which it contains, and then glance at the plant and
see the number of cups flourishing all over the leaves, we cannot
but be struck by the prodigious number of spores which there
must be altogether.

Dr. M. C. Cooke, in his book^ Rust, Smut, Mildew, and Mould,
writes, in reference to the JE.cidiuni on the Goatsbeard, that if we

ON THE STUDY OF MICRO-FUNGI. 371

compute 2,000 cups as occurring on each leaf, and suppose each

cup to contain 250,000 spores, then we shall have not less than

five hundred millions of spores on one leaf of the Goatsbeard.*

Whether yEcidium lapsancB can boast of such a wealth as that, we

shall not pause to consider, but the figures will give some idea as

to the sort of numbers attained when the spores are actually
counted.

If, now, we obtain some fresh specimens, and shake or brush
off the ripe spores at the tops of the cups into a little water on a
glass slip, we shall, without difficulty, be able to observe the ger-
mination of the spores. In order to confine a small quantity of
water for this purpose, it will be found very convenient to affix a
small indiarubber band to an ordinary glass slide with balsam or
some proper adhesive substance that will not readily wash off. I
have used cells made in this way for a considerable time and have
found them very satisfactory. When the spores are sown in the
water, the slide should be kept under a glass shade, in which a
dish of water is also placed to keep the chamber moist, so that
the water which is necessary to the germination of the spores does
not evaporate.

In reference to these rubber-band wells perhaps I should men-
tion, by the way, that they answer very well for the examination
of pond water with low powers. They are easily made, and being
much stronger than many types of life slide, can be freely cleaned
without danger of breaking. The cover-glasses adhere closely to
the indiarubber, and do not slip off. When some active organism
is under examination everyone knows how difficult it is to keep
the creature under view in the usual sized well, as it gives such
ample scope for demonstration of agility. If, however, a portion
be cut out of an indiarubber circle, and a small hole be punched
in the segment, it will, when fastened on a sHde, provide a small
well, the whole area of which will be covered by the lens, and
consequently the creature will always be under view (see PI. XVII.,

Fig. 7)-

But to return to the aecidiospores which we have placed in
water. They should be examined every now and then to see what
progress is being made. In two or three hours it will be seen that

* Dr. M. C. Cooke, Microscopic Fungi, 1 870, p. 8.

372 ON THE STUDY OF MICRO-FUNGI.

a germ tube has begun to issue from each of the ripe secidiospores,
and this tube will continue to grow until many times the length of
the spore from which it arises. Some of the tubes will become
much bent and curved about from side to side, and the coloured
protoplasm will be seen to leave the spore and flow slowly along
the tube until it reaches the end. Soon all the protoplasm will
have travelled along the germ tube, and the spore will be left quite
empty. The tube may become branched, and the protoplasm will
flow into the branches. Plate XVII., Fig. 3, represents a ger-
minating secidiospore.

Now that which takes place on the glass slide takes place also
on the Nipplewort. We have already stated that the spores
become scattered about, not only on the host plant itself, but also
on the surrounding vegetation ; when, therefore, there is a shower
of rain or fall of dew, these spores begin to germinate precisely in
the same way as we saw them do in the experiment ; but
the process goes further, for the ends of the germ tubes, or of the
branches of those spores which happen to be upon a leaf of the
Nipplewort, enter through the stomata into the tissues of the leaf,
and there develop, finally producing a fresh mycelium. The
empty spores and the portions of the tubes remaining outside the
leaves then fall off and disappear, as their mission is ended.

It must, of course, be borne in mind that, although all the ripe
secidiospores germinate when moisture is applied, it is only those
which are in touch with the proper host plant that enter the stomata
and give rise to a mycelium. The spores may have germinated in
hundreds on some neighbouring plant, but without producing the
slightest eflect. If we secure a few specimens of Lapsa?ta com-
mimis^ and also of some other plants, all of w^hich should be free
from any traces of fungus, we can easily test the accuracy of what
has just been stated. One or more leaves of the Lapsana should
be well moistened and some freshly gathered aecidiospores brushed
on to the wet surfaces. The plant ought then to be covered with a
globe for a day or two, so as to keep the leaves damp and afford
the spores an opportunity to germinate. If at the same time that
this is done we also inoculate some other plants, say the Daisy or
the Nettle, and in addition preserve a Lapsana from all contact
with any aecidiospores, they will help us to understand the process,
and will serve also as a check.

ON THE STUDY OF MICRO-FUNGI. 373

When these different plants are examined in about a fortnight,
no change will be observed in the Lapsana which was not inocu-
lated, nor will there be any signs of fungus on either the Daisy or
the Nettle ; but on the Lapsana, on which were placed the secidi-
ospores, there will be seen a quantity of very small light-brown
spots. These spots on examination with the microscope will
resolve themselves into sori or clusters of spores. They form,
indeed, the next stage in the life-history of the fungus we are
considering, and are termed uredospores. These uredospores are
the product of the mycelium formed by the development of the
germ tubes of the secidiospores. The mycelial tubes accumulate
in special centres, and from these parts there are branched off
large numbers of upright hyphae. At the apices of these hyphae
the uredospores ate formed, w^hich when ripe become separated
from the hyphae, in order that others may be developed in the
same way. The growth of the fungus at length breaks through
the leaf, and the ruptured epidermis can often be plainly seen
around the sori.

When the uredospores are separated from the beds on which
they have been produced, they usually become detached, not
exactly at the junctions between the spores and the hyphae, but at
a short distance below them. The spores are then free and ready
to be dispersed with the first breath of wind. The sori or spore
clusters, which are scattered over both sides of the leaves, are not
nearly so prominent and easily discovered as the previous stage of
the fungus, neither are the leaves distorted by the presence of the
mycelium as we saw they were when the aecidium was being
developed. The spores themselves are ovate, of a brownish colour,
about 1 8 micro-mm. in diameter, and are covered with short,
sharp points or spines. They will, of course, be found on the
Lapsana immediately after the aecidiospores, say, during the months
of April, May, and June, and if we obtain, as we did with the
previous spores, some of the ripe uredospores, we shall find
that, when placed in water, they will germinate in precisely the
same way.

In a few hours after immersion the germ tube will have been
extended through one of the germ pores in each ripe spore, and
the protoplasm and colouring matter transferred from the interior

374 ON THE STUDY OF MICRO-FUNGI.

of the spore to the distant end of the tube. The tube will become
branched, and, if the spore be upon a leaf of the Lapsana, it will
find its way through one of the stomata into the tissues, and there
grow and give rise to another mycelium. These germinating
uredospores may be placed upon other plants than the Lapsana —
as, e.g.^ the Daisy and Nettle again — but they will produce no myce-
lium in them. In this new mycelium fresh spore beds will soon
be formed, and hyphai given off as before in the direction of the
surface of the leaf. These hyphae become expanded at the upper
ends into oblong spores, or rather compound spores, for a trans-
verse division in the centre of each of these oblong spores divides
it into two chambers, thus practically making two spores, one above
the other. These are called the teleutospores ; that is, the last
spores which are produced. The teleutospores in many species
have only one cell or compartment, but in the present species they
have, as already stated, two cells, and are known by the distin-
guishing name of Fuccifiia. They will be found probably from
May to August, and will appear sprinkled over both surfaces of
the leaves in black or dark brown Httle spots.

We have seen that as soon as the aecidiospores and uredospores
were ripe, they germinated at once on being placed in water ; but
the teleutospores that we are now considering do not germinate
until spring of the following year. Throughout the winter months
they remain unchanged and exhibit no signs of life ; but after this
period of rest is over, and when the season once more comes
round for the Lapsana to put forth its young leaves, they are ready
to germinate. The process is somewhat different from the germi-
nation of the previous spores. Soon after moisture is applied to a
teleutospore two tubes are emitted, called promycelial tubes, one
from each compartment. The protoplasm passes out of the spore
to the far end of the promycelial tubes, where the tubes presently
become divided off into several compartments. From each com-
partment a fine short branch arises, along which the protoplasm
flows and accumulates at the end of it in a small, round body,
which is there formed, called a promycelial spore (see PI. XVIL,
Fig. 4). In a short time this promycelial spore drops off, and then
germinates by emitting a short germ-tube (see Fig. 5). This germ-
tube, when upon a leaf of the Lapsana, pierces through the epi-

ON THE STUDY OF MICRO-FUNGI. 375

dermis with its sharply-pointed end, and thus conveys into the
tissues of the plant the protoplasm from the promycelial spore,
which very shortly gives rise to the mycehum that produces the
spermogonia and secidiospores.

Thus have we arrived at the point where we started, having
followed the fungus through its various stages and described the
cycle of its life-history. The aecidiospores germinated and pro-
duced the uredospores, the uredospores germinated and produced
the teleutospores, and the teleutospores, after resting for several
months, germinated and produced the aecidiospores. From this it
may easily be understood that, until their life-history had been
made out, these several different spore-forms might very well have
been treated as so many different species of fungi ; but now it is
clearly established that they are but so many stages in the life of
one fungus, Puccinia lapsance.

Perhaps the following sketch of how a new species was found
and its life-history worked out may not be without interest to those
who are strangers to this branch of work. In searching any dis-
trict for these fungi it generally happens that some particular
locality at length becomes singled out as one which provides more
chances of success than others. One place which the writer
found particularly rich in specimens was a small, open, boggy spot,
perhaps only about twenty yards in circumference, in the midst of
a small wood. Very few persons ever found their way thither, so
that the vegetation was permitted to grow undisturbed and in a
wild luxuriance calculated to delight the heart of anyone who
loved to see things in a true state of nature. Part of an old tree-
trunk lay rotting amid the herbage, and near at hand trickled a
tiny stream. Around the margin grew various trees and shrubs,
and everywhere there was an abundance of flowers. In course of
time this delightful little spot became, in imagination, my own
peculiar property and a place across which no vulgar feet had any
right to tread. Under such circumstances it was only natural that
great disappointment, if not wrath, should be expressed when, on
proceeding one day to the old haunt, it was found that the wood-
man had been hard at work and levelled to the ground the little
wood and obliterated the happy hunting ground. Sic transit
gloria 7nundu

376 ON THE STUDY OF MICRO-FUNGI.

However, while this spot existed, I had free scope to prowl
about in quest of specimens, being only occasionally startled by
the sudden leap of some surprised frog or wondering toad. One
afternoon, when gathering in this place specimens of Uredo con-
fliietis^ which were growing freely on the Dog's Mercury ( Mer-
curialis pereimis), I noticed among the Mercury plants a single
specimen of the Herb Paris {Paris quadrifolia)^ and that on one
of the leaves there was a small, lightish-coloured spot which
seemed to indicate the presence of a fungus. On closer examina-
tion this proved to be the case, for on turning over the leaf an
JEcidium was seen to have established itself. Further search
revealed the pleasing fact that other specimens of the Herb Paris
which were growing near at hand were also infested with this
parasite. The fungus was growing both on the leaves and on the
stems of the plants, and although not present in any great profu-
sion was nevertheless sufficiently plentiful for all purposes. It was
further noticed that the area in which infected plants could be
found was very circumscribed ; indeed, that they were only to be
obtained within a circle of some six yards or so in circumference.
Beyond this circle a stray specimen or two might be discovered,
but the limit of their habitation was pretty well defined.

I was unable to find any reference to a fungus upon the Herb
Paris in the list of those which had been recorded as occurring in
Britain ; but it appeared probable that it might be the same species
as the one which grows upon the Lily of the Valley, seeing that
that plant is nearly related to the Herb Paris. However, on for-
warding some specimens of it to Dr. Plowright, King's Lynn, for his
opinion, he stated that in all probability it was quite distinct from
that species ; but in order to determine the species exactly its life-
history would require to be worked out. The aecidium was found
in the month of May, and by the end of June it had entirely
disappeared. Now, if this fungus went through the same cycle as
the Puccinia lapsajice^ the aecidiospores should have been followed
by the uredospores and then by the teleutospores, but no further
spores appeared on the leaves of the Herb Paris. It was therefore
evident that a clue must be looked for elsewhere.

Before going further, we should explain that there are a goodly
number of these fungi which spend part of their lives upon one

ON THE STUDY OF MICRO-FUNGI. 377

host plant and part upon another host plant of a totally different
species. For instance, Puccinia obsaira dwells during the aecidium
stage on the common Daisy {Bellis percn?iis), and during the Uredo
and Puccinia stages on the Field Woodrush {Luzida campestris).
Fungi of this nature are termed heteroecious, and they will not
develop unless the necessary two host plants are present. For
instance, the latter two stages could not be produced on the Daisy,
neither could the former stage be produced on the Luzula. When
the aecidiospores on the Daisy are ripe, they fall down upon, or
are blown on to, any specimens of Luzula campestris that may be
near at hand, where they germinate and produce in the ordinary
way the mycelium, which eventually gives rise to the uredo and
teleutospores. These last-named spores develop, in like manner,
when they find a resting-place on the Daisy leaves and produce
the secidiospores. This strange and peculiarly interesting feature
was therefore the clue which had to be followed in the search for
the missing links in the history oi Vadium paradis , as it appeared
highly probable that the species was heteroecious. I was unable to
follow up the quest that same year, but when opportunity served
an investigation of the plants growing in proximity to the Herb
Paris was made, and though there were several other species of
fungi close at hand, yet they were well known and had nothing to
do with the one in question. But just over the place where the
young Paris plants were raising their heads from the soil, a con-
siderable quantity of dry, withered Canary Grass {Phalaris arun-
dinaced) of the last year's growth was lying upon the ground, and
this grass was covered with very minute black spots, which on
examination proved to be little beds of fungi, Puccinia. This
discovery at once gave rise to what proved to be a well-founded
suspicion: that these spores were the very ones that were required,
but the only way in which the truth could be definitely ascertained
was by actually taking the spores and endeavouring to produce
from them the secidium on the Herb Paris.

A number of Paris plants, which were just beginning to unfold
their leaves, were therefore collected from a place where it was
considered they were in all probability free from the disease, and
some of the spores from the canary grass were placed upon the
leaves of several of them. One or two of the plants, however,

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. bb

378 ON THE STUDY OF MICRO-FUNGI.

were not infected, so they were retained as control plants ; so that
if the infected ones developed the secidium and the control plants
did not, then it would be pretty conclusive evidence that the spores
on the grass were the cause of the fungus on the Herb Paris.
Owing to some difficulties I experienced in getting the plants to
grow, my cultures were not successful ; but Dr. Plowright, who
very kindly took a deal of trouble in helping to work out its life-
history, was more successful, and I shall therefore give the results
which he obtained from his experiments.

When infecting with the teleutospores, it is prudent to make
sure, by placing them in water and examining with a microscope,
that they are actually germinating, otherwise spores might easily be
used for the experiments which have already germinated. Such
exhausted spores would, of course, be useless for the object in
view. Previous, therefore, to the spores being applied to the Paris
plants, it was ascertained that the promycelial tubes were actually
being developed. In about eleven or twelve days after infection
spermogonia appeared on the leaves of the plants which had been
infected, whilst the control plants remained perfectly free from the
parasite. This was very satisfactory, and showed at once the
connection between the spores on the two different plants. The
grass in question {Phalaris arundinacea)^ however, forms a host
for several species of Puccinia^ which respectively produce secidio-
spores on Allium ursinmn, A nun fnaculatmn, Convallaria ??tajah's,
and Rhamnus frangula, and it was therefore possible that the
Puccinia in question might be one of these species which, in
addition to producing secidiospores on the already recorded host,
also produced them on Paris quadrifolia.

As the Puccinia spores are in many cases so very much alike,
it is impossible by microscopical examination alone to identify one
species from another, and it is therefore necessary to cultivate the
various spores, and thus show which are related. The spores in
question on the Phalaris grass were therefore applied to Allium
ursinum^ Arum maculatum^ and Convallaria majalis ; but on
these plants they produced no aecidium. This proved that the
Puccinia had nothing to do with the other species referred to, as
it was inefficacious in producing the aecidium on all save the Herb
Paris, and showed that one more Puccinia had been added to

ON THE STUDY OF MICRO-FUNGI. 379

those already recorded as occurring on the Phalaris. It certainly
is very remarkable that, although they all find a congenial home
on the Phalaris and do not differ microscopically very much from
each other, yet each has its own particular host on which to spend
the first part of its life.

In order to understand how the Herb Paris becomes infected
in a state of nature, it is only necessary to remember that the
withered grass bearing the Puccinia was found lying on the ground
directly over the area where the Herb Paris was growing. The
young plants, therefore, required literally to push aside the fallen
grass in order to get space to grow, and multitudes of the teleuto-
spores would consequently be encountered both on the ground
and on the grass. The spermogonia were soon followed by the
secidia, that is the cups containing the secidiospores. The cups
are developed on the under surfaces of the leaves, hypophyllous,
and are arranged generally in the form of small circles. See PI.
XVII., Fig. 6. The circles, which are usually very definite, are
formed by a single row of peridiae or cups, with a vacant or clear
space in the centre. The places on which the aecidia grow, and
for a short distance round the margin of each circular spot, are
lightish coloured, owing to the chlorophyll being destroyed by the
fungus. The number of such circles of cups on each leaf does
not very often exceed two or three, but a leaf may occasionally be
found bearing five, six, or even more of them.

Having thus proved the case so far, the next step was to try
the reverse culture, to see if the secidiospores, when sown on the
Phalaris, would produce the uredospores. This was accordingly
done and also proved successful, for in about three weeks the
desired spores made their appearance on the grass. The sori or
spore clusters are small, of a reddish yellow colour, and were deve-
loped in fair abundance on both sides of the leaves. The spores
are globose, finely echinulate, and measure in diameter 30 — 35
micro-mm. In a state of nature, the Phalaris becomes infected, of
course, from the spores which are blown on to it from the Herb
Paris, and if there be moisture on the grass they straightway emit
the germ-tubes, which enter into the tissues in the usual way.
The uredospores are usually to be found in the month of July.
When they are ripe, they also germinate, and very shortly the

380 ON THE STUDY OF MICRO-FUNGI.

teleutospores (Puccinia) are formed on the same grass. The sori
of the teleutospores are very small, and are scattered about in
abundance like minute black specks upon the grass. The spores
are brown, smooth, and somewhat variable in form. The constric-
tion between the two compartments is generally very slight, and
the measurements are 40 — 50x18 — 25 micro-m.m. When the
teleutospores are fully developed in the month of July or August,
no further change takes place, and they remain inactive throughout
the winter. The grass which bears them withers and falls to the
ground, but when the Herb Paris is again springing up the spores
are ready to germinate and produce the mycelium of the secidio-
spores in the way we have already described.

We have thus completed the cycle of the life-history of Puc-
cinia Paridis, having traced it from the teleutospores on Phalaris
arundinacea to the secidiospores on Paris quadrijolia^ and then
back again from the latter plant to the former one, and so proved
the parasite to be heteroecious.

When we bear in mind the facts which have here been referred
to, the lowly and insignificant fungi will gain a fresh attraction for
us, and will become invested with a halo of interest which at our
first acquaintance with them we scarcely thought it possible that
they could possess. Indeed, it appears to us that because we
obtain a treat where we least expected it, that we are therefore the
more pleased when it is suddenly presented to us.

What has just been described regarding Puccinia lapsa7icB and
Puccinia Paradis no doubt applies in a general way to the develop-
ment of many other species ; but there are, of course, a great
number, to which we have not referred here, which have life-
histories much different from those just given. (Dr. Plowright's
work on The British Uredinece a?id UrtilaginecE will be found a
most useful and deeply interesting book in giving further informa-
tion on the subject.) Neither have we made any reference to
those species which attack the corn, the potato plants, and many
other of the fruits of the earth which are so valuable to man, and
in the study of which there is more than a mere passing interest.
But perhaps we have said sufficient to show that these micro-fungi
are highly deserving of our careful and particular attention.

Journal of Microscopy, 3^'^.^Ser. Vol.S. Plate 17.

W'W*t*nw»-Mi«*(0.-*.*-«W««^«»«HM»^ <ftfiSaW*^rtl3-^SWV«Srt«firt?*SKSJli'

.i,>jWMiiga*'Jt*Mi»''JHf^tf^w*»*'»'' '

7

OOKINESIS IN LIMAX MAXIMUS. 381

EXPLANATION OF PLATE XVII.

Fig. 1. — Section of a sperm ogonium, x 200.

2. — Section of an tecidium, x 150. De Bary.

3. — /Ecidiospore germinating, x 250.

4. — Teleutospore germinating.

5. — Promycelial spore germinating.

6. — Paris quadrifolia, showing secidium on under surfaces of leaves.

7. — Glass slip, with india rubber cell.

©bftineeie in Ximay flDayimue/'

By F. L. Washburn.

THE observations here given are confined to early stages of
the egg while in the oviduct, and before the expulsion of
either polar globule. The article, therefore, deals with
stages which, for the most part, precede any discussed by Dr. Mark
in his excellent treatise on Z. campestris.\

Of the following wood-cuts, Fig. i is a diagrammatic represen.
tation of the oviduct from a laying animal, from which eggs were
taken, and studied serially as numbered. The vitellus averaged

ft,^

Fig I.
i56"2^ in diameter. Various methods were made use of in fixing
— Fols solution : Osmic acid, i per cent., followed by Merkel's
fluid j chromic acid 1/3 per cent., etc. ; but the one which gave

* Reprinted from American Nahcralist, June, 1894.

t "The Maturation, Fecundation, and Segmentation of Limax Catnpestris
Binney," by E. L. Mark, Bulletin of the MtiseuDi of Compaj-ative Anatomy,
Vol. VL, parts 11 and 12, Cambridge, Mass., 1881.

382 OOKINESIS IN LIMAX MAXIMUS.

the best satisfaction was as follows : — The body cavity of a laying
animal was opened with a quick cut of the scissors, and the animal
plunged into a boiling hot solution of corrosive sublimate; allowed
to remain one minute ; transferred to water, and eggs removed
from oviduct and shelled/'^' Vitellus allowed to remain in distilled
water two minutes, then transferred to 35 and 50 per cent, alcohol,
remaining three mintes in each grade; then to 70 per cent, alcohol
for permanent preservation. I found that if eggs were allowed to
remain in distilled water three hours or more, they shelled better,
the vitellus coming out clearer and freer. For examination ofeggs
in toto^ Czokor's alum cochineal gave, as a rule, good results. Ten
minutes' stay in this dye appeared to give the necessary differenti-
ation ; but for examination of sections much longer time was
necessary, two to three hours or more. Picrocarminate of lithium
was also found to be excellent, if anything, better than Czokor, on
account of its differentiating nucleus structures. For examination
in toto, twenty-four hours in this stain, and then washing with
distilled water and pure alcohol, gave good results.

Section staining on slide was also found desirable, and Safranin
was the stain used — two and a half hours, followed by acidulated
(I per cent. HCl) alcohol of 90 per cent, grade for seven to ten
minutes. The Schallibaum should be new, the sections carefully
applied to a well-smeared slide, and kept at 60° C. for exactly
fifteen minutes. If Mayer's albumen fixative is used, only warm,
and as soon as paraffine is melted remove slide from heat.

A number of sections of the hermaphrodite duct {k.d., Fig. i)
were made. One egg was found, in this duct, near the hermaph-
rodite gland, containing two polar corpuscles, each surrounded with
a faintly stained Hof, and each showing striae radiating from cor-
puscle through Hof. About eight chromosomes were observed
irregularly grouped in the well-defined archoplasm of Boveri.t

From these sections it appears that the centres of attraction

* In the upper part of the glandular portion of the oviduct there were a
number of eggs in which the outer membrane or shell was barely formed ; in
some, egg No. i for example, there was no membrane at all, and in others only
the inner membranous coat was present.

t Zellen-Studen von Dr. Theodor Boveri, Jena, 1887.

OOKINESIS IN LIMAX MAXIMUS.

383

which Garnault "^ says do exist in the ovarian egg of Arion and
Helix^ and which were not seen in the hermaphrodite gland of L.
??iaxifmis, do exist in the duct very near the gland. They evidently
appear immediately after the egg has left the ovary. This duct
was lined, for the most part, with ciliated epithelium, and con-
tained much mucus.

Fig. 2 illustrates an optical section of egg No. i from glandular
part of the oviduct (see Fig. i) viewed obliquely to the long axis
of the spindle, and showing the two polar corpuscles and chromo-
somes, there being about twenty of the latter lying in an irregular
cluster in the clear space between the corpuscles. This egg was

Fig. 2.

stained in picrocarminate of lithium for thirty hours. In its exam-
ination a Zeiss Oc. 2 and Obj. E were used. A broken membrane,
" membrane rongee," was seen with apparently chromatic thicken-
ings in it. Observations on this egg coincide closely with those of
Garnault on Arion and Helix ^ and, in a measure, with those of
Vejdovsky on Rhynchebnis.\

The larger corpuscle is the one nearest the observer. The
structural peculiarity of one side of the nucleus should be noted —
where cytoplasm and yolk granules are in intimate relation with
contents of nucleus. This is Garnault's " prophase ; " it is the
stage just previous to formation of nuclear plate leading to the
forming of first polar globule. In another egg, No. 9, from the
same oviduct, an optical section showed rays of hyalocytoplasm

* " Sur les phenomenes de la fecundation chez I'Helix aspersa et I'Arion
empiricorum." — Zool. Anzeiger^ Nos. 297 & 298, Dec, '88, and Jan., '89.

t Die Entivecklungsgeschicete der oligochaeten ( Rhynchelniis), 1888.

384

OOKINESIS IN LIMAX MAXIMUS.

pushing out from clear area through granules of vitellus. Chromo-
somes irregularly placed in a hyaline area. Spindle striae observed
in viewing the egg at right^angles to spindle axis.

Fig. 3.
Fig. 3 illustrates an optical section of egg No. 1 1 from oviduct
of another animal, occupying the same relative position as No. 11
in the oviduct drawn. In an eccentric position, and near the
surface, a clear circular area with radial striae was observed, indica-
ting the presence of the male pronucleus. A portion of the
membrane of the germinal vesicle still present. Egg No. 10, in
the same animal, also showed circular male area in direction of
axis of spindle, and chromatin granules within it. In egg No. 9
the head of spermatozoon was seen in optical section, some little
distance from periphery, circular with narrow Hof about it, and
striae radiating from Hof. Very fine granules were evident within
this pronucleus.

Co a <r/ ''o '-^ e <■"-> ^'o

Fig. 4.

OOKINESIS IN LIMAX MAXIMUS. 385

Fig. 4 illustrates part of a section of egg shown in Fig. 2, cut
in such a plane as to show the sperm nucleus near the periphery.
Drawn with Zeiss Oc. i and 1/18 oil immersion. Garnault says,
in speaking of formation of sperm nucleus in Ario7i and Helix,
" the spermatozoon enters just before first kinesis, or immediately
after. The contracted head does not begin to change until after
the expulsion of the second polar globule. The sperm-head first
divides into two chromatin spherules, then, by successive divisions,
there is formed a greater number of spherules which remain
inclosed in a clear areole. This clear areole recalls the hyaline
centre of attraction when that has received the half plate for the
formation of a vesicular nucleus." *

* The following few notes pertaining to the fixing and staining oi freshly
laid eggs may be of interest : —

Eggs placed for five minutes in Fol 99 (i per cent, chromic, 25 vol ; 2 per
cent, acetic, 50 vol ; H.^O, 25 vol), then shelled in water ; vitellus in same
solution for five minutes, H2O ten minutes., and 35 per cent, and 50 per cent,
alcohol five minutes each, 70 per cent, thirty minutes, and 90 per cent, ad lib.,
gave good results, taking picrocarminate of lithium very well if left long enough
in stain. They also took borax carmine very well after the above treatment.

Both of these stains did well after the eggs were immersed in chromic J per
cent, ten minutes, then shelled in large quantity of water, then vitellus in
chromic J per cent, four minutes, and H2O and grades of alcohol as above.

Whole egg in osmic acid i per cent, five minutes, followed by Merkel's fluid
four hours ; shell, then water, and grades of alcohol two minutes each to 70
per cent, for permanent preservation were quite satisfactory. It gave good
results as to nuclei when eggs were left in picrocarminate of lithium for
forty-eight hours.

The Torpedo Fish. — At the last meeting of the Academy of
Science, Philadelphia, Prof. D'Arsonval, of the College de France,
said : — A fish 30 cm. in diameter could give out a shock of 20
volts. He applied some small electric lamps to the fish, and they
were lit by the discharge from its body. In some instances they
were so powerful as to carbonise the lamps. — Sci. American.

[ 386 ]

Ipbotoorapbing fIDinute ©bjccts b^
fIDeane of tbe flDicroBCope.

By T. E. Freshwater, F.R.M.S., F.R.P.S.

(Read before the North Middlesex Photographic Society.)*

I FEAR I have nothing new to bring before you this evening,
but having been pressed into the ranks by your secretary I
will endeavour to do my best. The subject is one that has
been dealt with by many men much more able than I am, and, if
I am not mistaken, you have several good workers in this Society.
I do not intend this evening to touch upon high-power work, but
treat the subject quite from a popular point of view. The slides
which I will show you are a few of the many that I have done to
illustrate various subjects, and taken under different conditions to
show a few of the methods of illumination.

It is not necessary to spend much money in rigging up an
apparatus for ordinary photo-micrographic work, for most objects
can be photographed with very inexpensive tools. The simplest
method is to use an ordinary microscope. Of course, the better
the stand is and the more stage adjustment the better, but it is not
necessary. The instrument should be turned down with the body
horizontal to the base of your apparatus ; then at the eye-piece
end fit up your camera. A half-plate with a long body will give
you plenty of extension for low-power work. For light you may
use that which is most convenient, daylight, lime, or lamp light.
A good large single-wick paraffin lamp will answer for all ordinary
purposes. The bull's-eye condenser on a stand should be placed
in such a position as to fill the object to be photographed with
light evenly all over. This part of the operation must be done
very carefully. Too much trouble cannot be taken with this
part of the work, as so much depends upon even and
proper illumination of the object in the resulting negative. It
is well that the whole apparatus should be fitted up on a
long, heavy, flat board, and very carefully centred, and made as
true and steady as possible. With such simple arrangements as

* From T/ie Amateur Photographer. We beg to thank the editor for the
loan of electros illustrating this article.

PHOTOGRAPHING MINUTE OBJECTS. 387

this, most of the ordinary objects may be photographed, such as
parts of insects, sections of wood, and most of the larger diatoms.

There are many different forms of photo-micrographic appara-
tus on the market now ; most of the opticians make one or other
form a stock article. Of some of the better instruments I will
show slides that I have made on purpose, then perhaps it will be
better to explain them. The most complete apparatus that is in
use, I think, is the one at the Royal Veterinary College. This
cost a lot of money, and is quite out of the reach of the amateur;
you will see by the slide how it is arranged. There are several
vertical instruments made. One by Van Heurck consists of
an oblong box, mounted on four legs of such a length that the
ocular end of the microscope passes through the bottom of the
box ; the box is large enough for the head to pass in for focussing
purposes. Another, designed by Mr. Pringle, has many advantages
over the solid box, as it is made with a conical bellows, and the
screen is made to slide down. For some objects a vertical camera
is necessary ; there are objects that you cannot keep flat unless
the stage of the microscope is horizontal.

When one starts in this line or branch of photography there
are several points to be taken into consideration. First, there is
the apparatus — I should advise anyone who is beginning, to buy the
best and steadiest microscope stand that they can afford, and with
a sub-stage for the various fittings that will be wanted from time
to time ; the long bellows camera, with board, is not an expensive
part of the apparatus, and can be bought for ^3 or ^4. Then
come the lenses ; these are most important, and, like photographic
lenses, rather expensive articles to deal with, if one goes in for
high-power work. But I am not going to touch on this line, so
will leave it to others who go in for deep scientific research, such
as the different forms of bacteria. The Germans have, hitherto,
made most of the best lenses for photographic work, and sell
lenses with a focussing eye-piece for correction — lenses that have
given better definition, flatter field, light, and more even illumina-
tion which come about by the use of the new glass from Professor
Abbe, and again they are cheaper ; but now the English opticians
are beginning to wake up in this direction, and many lenses are
made that are quite as good and no more expensive ; in fact, I

388 PHOTOGRAPHING MINUTE OBJECTS

have some that it would be difficult to beat as regards defining
power and the amount of light that they pass. For micrographic
work it is an immense advantage to have more light than you want,
as it can always be stopped down by the use of the iris diaphragm,
or as some prefer a set of stops, these perhaps, in many cases, have
an advantage. I think it is well never to use a higher power than
you can help ; it is better to get the amount of magnification by
extending the camera, and put in an ocular or compensating eye-
piece ; these are made on purpose, and work with a spiral motion
to the eye-lens, so as to focus the diaphragm stop in the tube. A
simple form of apparatus I have designed and will show you a
slide of presently. The camera is of long extension, and has a
bellows 30 in. long ; the front part is made to rack back, so as to
clear the eye-piece of the microscope, to enable the operator to
revolve the instrument on its centre. The microscope is one of
a new series of stands Messrs. Newton have recently brought out,
and for all ordinary work will answer every purpose ; it has a
simple mechanical substage, fitted with an iris diaphragm and
Abbe condenser, with adjustments for centering ; the mirror is
made to swing out of the way when not in use.

A very convenient way of seeing how to arrange the object is
to place a flat mirror at some distance from the ground glass at
the end of the camera ; the image on the screen is reflected on
to it. You can by this means see that the object is in the centre
of the field, and easily focus the object and centre the light ; in
fact, you can, without any difficulty, get the whole thing ready in
a short time, except the final focussing, which has to be done very
carefully. Having now roughly focussed the object, remove the
ground-glass screen, insert a plate of plate-glass with lines ruled
on it, and it will be found useful to have these lines ruled at a
given distance apart, say one-tenth of an inch, and a Ramsden
eye-piece used for focussing aerial images; coloured screens or light
filters are very useful. It is well to be provided with several differ-
ent ones, such as signal green, bluish grey, and yellow, and a few
cells fitted with coloured fluids, for, in many cases, working in
monochromatic and coloured light, according to the object to be
photographed, is necessary. I had intended to show you a num-
ber of photographs taken with various screens, but have not had

BY MEANS OF THE MICROSCOPE. 389

time to prepare more than one or two. One of the advantages of
their use is that, if the object is very dehcate and likely to be
flooded with light, the use of the screen comes in, and for objects
that it would be almost impossible to expose quick enough ; the
insertion of a suitable screen enables you to make a good expo-
sure and get all detail, notably in the dehcate membrane of some
of the wings of flies, etc.

With regard to illumination, as I have said before, an oil lamp
will do very well ; but if you can get the limelight it is more
satisfactory. The light is more pure in colour, more intense, and
more easily under control.

Working from a small spot of light, and the smaller and more
intense the better, the ray goes more direct through the centre of
the optical system than a large volume scattered about. A blow-
through jet will answer all purposes, and if it is fitted with a
Pringle cut-ofl" — that is, an arrangement for lowering the gases
between the exposure — you save the gas and also make sure of
getting the same amount of light each time.

For time of exposure one can give no fixed rule, so much
depends on the subject, its colour, thickness, the amount of den-
sity, and the magnification wanted. With reference to the plate,
use a slow, thickly-coated one for most work. The isochromatic
will be found very useful for many subjects, but I have not found all
the advantages that are claimed for them, for of the number of
slides that I hope to show you very few are taken on those plates.
Nearly all my negatives were done on Paget xxx or xxxxx.

Each class of object requires a special study. By class I mean
transparent, high or low power, opaque, objects taken on a dark
ground, and objects taken by means of polarised light ; each of
these I shall more or less speak upon. The ordinary objects,
such as a blow-fly's tongue, wing of bee, stings, head, internal and
external organs, sections of scalp, and thousands of others, can be
taken in the way I have explained, and with a 4-ioth to 2 in.
objective with very little trouble and not much practice. High-
power work, using an immersion lens of, say, i-i2th, requires a
very great deal of care and manipulation of the whole apparatus,
from the achromatic condenser to the ocular.

Many objects that are opaque are very interesting to photo-

390

PHOTOGRAPHING MINCJTE OBJECTS

graph. Very little, so far as I can see, has been said about them ;
I allude more particularly to the eggs of the various parasites, the
coarser foraminifera, scales on the wings of beetles in situ. Now,
these are more difficult to do, and some of the best work in this
way I have seen has been done by my friend Mr. Evans, and I
think — in fact, I know — they are not to be equalled. I candidly
confess I cannot do them nearly so well. A few of my attempts
I will show you. As all the light we have to deal with is that
which is reflected from the object itself, it is absolutely necessary
to concentrate all the light possible on the object. There are
several ways of doing this, but first of all your object must be
mounted very flat, and in the centre of a small black disc, so as
to allow the light to pass round the object from your condenser.

The Stomach Bones of Brittle Star Fish.

This light then falls upon a silvered reflector or Lieberkuhn
mounted on the objective, the curve of which must be equal to or
a little longer in focus than the objective, so that when the object
is in focus, a small amount of collar adjustment enables you to
focus down and adjust the rays of light that have been received
upon the silvered surface of your reflector. Of course, the more

BY MEANS OF THE MICROSCOPE. 391

light you can get on your object the better will be the resulting
negative.

Such objects as small shells, eggs of butterflies, polycystina,
light-coloured seeds, in fact, anything that will reflect and not
absorb the light, may be photographed in this way. A parabolic
silver-side reflector is sometimes used, but this is not nearly so
good, you are apt to get strong shadows on one side. I am sorry
I shall not be able to show you many examples of my work in
this direction, but the few I have will show you the beauty of
their structure, and how easy it is to make pictures of such minute
things. I have a lovely specimen of the eggs of the parasite of the
Reeves pheasant in situ clustered on the feather of the bird.

Eggs of Parasite of Reeves Pheasant.

Objects photographed under polarised light are very pretty;
some objects, such as starches, sections of rock, crystals, that are
perfectly transparent under ordinary light, when polarised are very
beautiful. Now if the two prisms are so turned that the object
comes on the dark field, they show up all the beauty of the struc-
ture and varied form and composition that, under other circum-
stances, would not be seen. The polariser, that is the prism near-

392

PHOTOGRAPHING MINUTE OBJECTS

Eggs of House Fly.

Salicine.

BY MEANS OF THE MICROSCOPE.

393

Selected J3rATOMs.

DiATOMACE^— Various.

I«™k.«.K,... JOUK.M.^OP M,CKOSCOPV ..O N.XUK.. SC,..CK.

cc

i

394 PHOTOGRAPHING MINUTE OBJECTS.

est the light, should be as large as possible, so as to pass as much
light as you can through the object. The analyser follows on at
the back of the objective, and should be mounted as close to the
back lens of the objective as possible, otherwise it will cut off some
of the field, and, to get the best result, both the polariser and
analyser should be made to rotate. A secondary condenser may
be placed in front of the Nicol with advantage.

Work done by dark ground illumination has a great charm,
more particularly to the student who has a love of pond life, and
to see the minute organisms scudding about lit up like small par-
ticles of silver on a black ground. The common hydra, vorticella,
and many others may be photographed by one who gives it his
careful study. Diatoms, sponge spicules, polyzoa, and many other
objects look grand done in this way. The few slides that I shall
show I hope will bear me out. I fear that I have taken up a lot
of your time, and you are getting tired of this dry stuff ; there are
several other matters that I might have dealt with, but it would
take up too much time in the one evening.

The Rays of the Solar Spectrum. — The fact is well known
that if we examine the spectra furnished by the light emitted by
the various points of the sun, the rays that appear are very variable
in number. There exist but eleven that are constant — that is to
say, that we find in the light derived from all the regions. Among
these, five belong to hydrogen, two to calcium, and four to
unknown elements. Mr. Ramsay, however, has identified one of
these rays — that of helium, with the ray of a terrestrial element.
There remained then but three, corresponding to extra terrestrial
substances. Mr. Deslandres has decomposed clevite by sulphuric
acid, and then, on studying the spectrum of the gas disengaged,
has ascertained the existence or a ray 447 "i 8, identifiable with
one of the three remaining rays. In consequence of this dis-
covery, there exist but two unknown rays among the permanent
ones of the spectrum. — Set. American.

[ 395 ]

Iprc&acioue & Iparaeitic lEneiniea of apbibee

(tncluMno a Stub^ of IT^i^pet^parasttes),

By H. C. a. Vine.
Part III. Plates XVIII. and XIX.

'^T^HE Hymenoptera as originally arranged by Linnaeus included
X those four-winged flies whose wing venation, differing
wholly from the Hymenopterous type, consists of longitu-
dinal nervures, more or less connected by transverse branches.
The value of this character has been strongly disputed by later
naturalists, but it seems probable that in this, as in so many other
instances, the generalising insight of Linnaeus led him to a con-
clusion which the labours of entomologists will ultimately confirm.
I may be able in the succeeding section to adduce some facts
which bear upon this question of the relationship of the Odonata
to the Flanipetinia, which has a certain interest in connection
with the aphidivorous genera, as establishing their relationship to
a very destructive carnivorous group, which dates back in geolo-
gical times to the Palaeozoic formations, and which may be contin-
uously traced through the Triassic and Oolitic strata. Indications
of the aphis-eating genera are not found until a late date, the
remains being found chiefly, I believe, in the Tertiary deposits.
This may be accounted for partly by the more delicate and fleshy
nature of the HemerobiincB^ and if we accept their relationship with
the Odonata as established, we may consider the probabilities of
their later appearance as arising from their being the product of
selection acting upon the more plastic species of the earlier
Neuroptera.

The beauty and elegance which characterise so many of the
Neuroptera are not wanting in those genera which, being aphidi-
vorous in their larval stage, come within the scope of the present
memoir. It is true that in Hemerobius one sees little save a dull
and often somewhat clumsy brown insect sometimes resembling a
small moth. But a slight examination of the wings reveals an intri-
cate venation and often a beautiful mottling which this genus
shares with many of the larger dragon flies ; while the delicate

396 PREDACIOUS AND PARASITIC

greens of the Chrysopidcs^ the elegant reticulations of their ample
wings, and the metallic brilliancy of their protruberant eyes, place
them among the most beautiful of insects.

It has been already mentioned that the larvae of these two
groups resemble one another very nearly in general characters, but
present also many points of difference.

In the last section I described the more important appendages
of a larva of Chrysopa, which were delineated with some detail on
Plate XII. The tapering length of the organs and the specialisa-
tion of the parts seems to indicate that the development has
progressed considerably beyond that of the Heirierobiidce^ and one
might almost think that in the Chrysopidce the evolution of the
larva had reached its maximum, did we not know that in such
things there is no finality. The corresponding organs of the larva
of an Hemerobius, shown on PI. XVIII. at Figs, i, 2, 3, and 4, will
illustrate this difference very clearly. The chitinous external
casings are much more fully retained, forming upon the palpi a
close series of incomplete rings, or, rather, perhaps, of flat plates
tapering to the ends and bent into segments of a circle. These
rings or plates are of irregular length, and are regular in their
disposition only inasmuch as they are so arranged as to cover the
surface equally. In fact, their appearance at once gives rise to the
notion that the chitinous covering has originally been continuous,
or comparatively so, but that the necessity, and consequent efforts,
at flexion have first wrinkled and ultimately separated (on the lines
of the wrinkles) the hard surface into a series of irregular plates,
which, disposed upon a flexible membrane beneath, present no
obstacle to the free movement of the organ. The palpi are com-
paratively short and thick, while the first and second joints of the
organs which are equivalent to labial palpi are encased in a con-
tinuous chitinous coat. The maxillary palpi — which I have else-
where spoken of as antennae — exhibit in some of the larvae of
Hemerobius enlargements as shown in the drawing, which recall at
once the characters of the antennae in some of the less developed
(or retrograded) Aphidida. The impression thus formed, that the
larva of Hemerobius represents a less specialised development than
that of Chrysopa is confirmed when we observe the short and
slight nature of the terminal bristles.

ENEMIES OF APHIDES. 397

The Mandibles and Maxilla.

The mandibles of this larva, as shown at Fig. 2, are corres-
pondingly shorter and thicker than those of the Chrysopa larva,
shown on PI. XII., and are provided towards the apex with three
or four denticulations, well adapted from their shape to prevent the
escape of prey, when once pierced. Lower down, the inner edge
is finely serrated, but the value of this is far from evident, the
mandible being rarely inserted in the body of a victim to any
depth.

The hollow-grooved shape of the mandible is well displayed in
this specimen. At Fig. 3, on the same Plate, is shown the
maxilla withdrawn from the mandibles. The transverse opening
at the extremity, through which the juices of the aphis are sucked,
is very evident, and a long fold or groove down either side simu-
lates very closely a longitudinal continuation of the slit, but a
careful examination reveals its true nature.

It has been stated by some writers of authority that the maxillae
are so shaped as to simply close the groove of the mandibles, so
that the two together form a hollow tube, which acts as the channel
to the oesophagus at their base. I have been unable to find any
evidence to confirm this view, and after frequendy watching under
the microscope the action of larvae in abstracting the juices of
aphides, I cannot doubt that the latter enter the tubular and
greatly modified maxillae by the narrow opening at their extremity,
and pass downwards by the suctorial action of the oesophagus into
that organ. The action of the mandibles is, in my opinion, limited
to the purposes for which their structure adapts them — the piercing
the skin of the victim, and affording a safe passage for the action
of the maxilloe, which they protect. Anyone who will take the
trouble to watch a larva seize and destroy an aphis under an inch
or half-inch objective, which may readily be done by confining the
insects in a shallow cell, will almost certainly deduce, from the
movement of the maxillae and the downward passage of the
ingested oil-globules from the aphis, that the function of the man-
dibles themselves is merely that of a weapon and a sheath.

The entire absence of any opening at the superior end of the
oesophagus, answering to the ordinary nature of a mouth, is one of
the most curious features of the Neuropterous group to which the

398 PREDACIOUS AND PARASITIC

Aphidivorous larvae belong. The labium appears to be firmly
united to the lower portion of the head, and no representative of
the ligula foreshadows the elaborate mouth-organs of the perfect
insect. This peculiar construction is the more remarkable, as in
other sections of the Neuroptera, in which the larvae, though of
different habits, present many points of resemblance to those of
He7nerobiincB, the victim is likewise seized by a pair of formidable
forceps, but is conveyed to the month to be devoured. So far as
I have myself observed, the absence of mouth in the larvae coin-
cides with certain features of the ligula in the imago (which will be
illustrated), but I am scarcely able to assert this as a general fact.

The Tarsus of the Larva.

Another noticeable feature in the species illustrated on PL
XVIII. is the entire absence of the elongated extension of the
tarsus, carrying at its extension the pulvillus, which is so strongly
developed in the larva of Chrysopa. In the Hemerobius larva
the suctorial pad is situated immediately at the base of the claws,
but although thus much less obvious, it appears to have very con-
siderable adhesive power, as is evidenced by its ability to climb
vertical glass surfaces when fully fed. The larva of C. Perla
during the latter part of its existence seems quite unable to adhere
to such a surface for a much greater height than about twice its
own length, when it usually falls back and regains its feet with a
struggle. The length of the slender articulation bearing the suc-
torial organ in the latter larvae probably has much to do with the
difference, as the leverage must greatly weaken the power of
adhesion.

The Wings.

The Neuroptera Planipennia derive their sectional designation
from the flat and broad expanse of the wings, which, especially in
the typical genus, Chrysopa^ are of great size, and in many species
assume a shape approximating to that of a parallelogram. The
hind wings are never larger than the fore wings, but in many of the
genera are equal in size and similar in shape and venation. They
are not, as in the Hymenoptera, supplied with wing-hooks, but
each pair of wings is propelled independently by its own muscles,

ENEMIES OF APHIDES. 399

and, in some species of the nearly related dragon-flies, are pro-
vided with means of instantaneously reversing their action.

In the ChrysopidcE^ as typified by C. perla^ the venation
of the wings is characterised by three or four longitudinal ner-
vures proceeding in determinate lines from the base of the
wing. In addition, some more or less zigzag veins connect the
numerous transverse veins in such a manner as to form an appro-
ximation to a longitudinal nervure ; but a slight examination of a
few species shows that this appearance is due merely to the coinci-
dence of the junctions of numerous short veins.

The main character of the wing is given by the transverse
veins, which, dividing the longitudinal space into more or less
numerous cellules, give the net-like effect that has obtained for
these flies especially the name of " lace-wing."

Both the anterior and posterior wings in the HemerobiincB are
studded with short, curved, and rather thick hairs along the lines
of the veins, becoming more marked in some species around the
edges and towards the base, and also about the point where more
or less indication of a stigma is sometimes found. No dark
mottling is found in the wings of Chrysopa^ but the green colouring
sometimes varies considerably, especially on the nervures.

The wings of the HetnerobiidcB — one of which, carefully drawn
for comparison, is shown on PI. XIX., Fig. 6 — present less
appearance of transverse venation, and the main longitudinal ner-
vures are fewer, or, at any rate, are not so much in evidence.
The veins, which in Chrysopa are transverse, here become more or
less oblique or longitudinal, some of the short connecting veins
remaining to form the spaces between into cellules. These wings
are often freely motded with a considerable number of dark
patches, affecting the nervures as well as the membrane, and short
hairs are fringed pretty thickly along the lines of the veins, as well
as sparsely on the surfaces between.

Many years ago, Mr. Bowerbank pointed out in the pages of
the Entomological Magazine (Vol. IV., p. 179) the beautiful phe-
nomenon of circulation exhibited in the wing venation of Chrysopa
perla. This interesting illustration of the vital processes of the
insect seems to have been but little noticed by microscopic observ-
ers, owing, no doubt, to the fly being rarely examined while living

400 PREDACIOUS AND PARASITIC

under any higher magnifying power than that of an ordinary hand-
glass. On PL XIX., at Fig. i, I have reproduced Mr. Bower-
bank's excellent drawings showing by means of arrows the course
taken by the currents within the veins. So far as I have been able
to observe, it appears that the veins themselves form the circu-
latory channels or vessels, the fine tracheae which pass through
them being perpetually bathed in the moving fluid.

An enlargement of portions of the wing veins is given at Figs.
2, 3, and 4 on the same Plate, showing within^ the trachea easily
visible from its characteristic structure. These tracheal tubes may
be easily seen and their course traced throughout the principal
veins of the wing by placing it in Canada balsam (fairly thin)
under a cover-glass, when, on exerting a slight pressure by means
of a needle while the slide rests upon the stage, the balsam may
be seen following up the tracheae and driving the air before it in a
very striking manner. The diameter of the tracheal passages, as
shown in Fig. 4, is stated by Mr. Bowerbank at about 1/2 2 2 2nd of
an inch, while the circulating passages within which they lie are
about i/4o8th of an inch.

The Antenna of the Imago.

The antennae of the Heinerobiiiice have shared the confusion
which has affected the descriptions of the family. They have
been variously described as moniliform, fiUform, setiform, beaded,
cylindrical, and thread-like.

The antennae of HemerobiidcE are always of the monili-
form or beaded type, although the shape of the segments
varies from that of a shortened and reversed champagne bottle
to almost globular. The number of segments is always con-
siderable, fifty to sixty being about the general number. The
lower segments sometimes present a slight elongation, but
the ultimate segment differs in no respect from those pre-
ceding it, except that it is terminal. The antennae are more
or less hirsute, and some species — as that figured on Plate
XIX., Fig. 8 — are characterised by short, stiff bristles, arranged
almost or quite at right angles to the axis of the antennae, on the
edge of each segment.

The antennae of the Chrysopidce. are long, consisting of some

ENEMIES OF APHIDES. 401

sixty, seventy, or eighty joints. The segments are perfectly cyUn-
drical throughout, closely jointed, and, excepting the third, which
is longer, are of equal length Their appearance is that of a
round cord, divided at short intervals by transverse divisions.
They are covered with small hairs, laid evenly in the direction of
the axis, and I have never observed any deviation in this respect.
An antenna of Chiysopa, containing an unusually small number of
segments, but otherwise typical in structure, is shown on PI. XVIII.,
Fig. 7. The antennae of the Coniopterygidoe are moniliform and
less hirsute than in Hemerobms. The number of joints is also less,
although it does not appear to have any definite relation to species.

The Cocoon.

The material from which the silky threads of the cocoon is
spun is derived from a gland situated in the posterior part of the
abdomen, and which opens by means of a short duct just within
the anal orifice. There appears to be no special organ for regulat-
ing the outlet, but the muscular bands connected with the sur-
rounding parts seem to control the duct, and probably when the
flow of silk-forming secretion is once established the larva has little
power of arresting it until the gland has completed its function.
Consequently, if a larva commences to spin on an unsuitable
surface — such as a glass cell — it does not stop after a few trials,
but goes on until it seems unable to make more silk, exhausting
its supply in making continual attachments to the glass in the
hope of obtaining a sufficient basis for the cocoon. The thread
itself, which is shown at Fig. 5, as spun on a cover-glass, is a fine
cylindrical cord of glutinous substance, which hardens imme-
diately. It is free from enlargements or irregularities of any kind,
and entirely devoid of any structure or duplication. It varies at
times in size, and is sufficiently adhesive as it leaves the larva to
broaden into a sticky mass, which is attached to convenient posi-
tions for the support of the pupa.

The cocoon varies in shape and size, that of Chrysopa being
round or barrel-shaped and of a very dense texture ; that of
Hemerobius oval or egg-shaped, and consisting of comparatively
few fine and gauzy threads ; while in Coniopteryx the cocoon is
also oval, but is composed of dense spun silk.

402 PREDACIOUS AND PARASITIC

In all the genera of ffemerobiince the pupae are far smaller than
the larvae ; in Chrysopa^ about one-half the size ; and are so
utterly disproportioned to the large insects that emerge from them
that it is difficult to believe, after the metamorphosis is complete,
that there can be any connection between the very small pupa-
case and the handsome fly. Dr. Fitch remarks that it is as if a
full-grown larva had hatched from an ordinary egg.

The Classification of Aphis-Eating Neuroptera.

The classification of the Aphidivorous genera of the Neurop-
tera has become strangely confused, the names of one or another
genus having at different times not only being altered, but trans-
posed. At present it will not be needful to address ourselves to
the vexed question of the transference of certain families of the
original order or to the Orthoptera, as has been done by some
naturalists, inasmuch as the Aphis-eaters are to be found among
those genera which are peculiarly typical of the Linnean order of
Neuroptera. But if it be possible in a future section, it will be
extremely interesting to consider the evidence of relationship
between those genera and some genera of the Odonata.

In order to enable the reader to see at once the views of
leading writers on the position of the genera of He?nerobimcB, I
shall give the classification adopted by them, commencing with
that of Professor Westwood. He divides the order as follows : —

Order, NEUROPTERA (Linneus).

Families. — Psocidce (Leach), Book Mites.
Perlidce „ Stone flies.
Ephemerid(B ,, Day fly.
Libellulidcd (Westwood), Dragon flies.

Sub-fam. — Agrionides (Westwood) .

HenierobiidcB (Leach), Lace-wings.
SialidcB (Leach), Alder flies.
Panorpid(B (Leach), Scorpion flies.

Family Honerobiidm : —

Genus Osmylus (Latreille). Ocelli, three, placed in triangle
on forehead.

ENEMIES OF APHIDES. 403

Genus Drepanopteryx (Leach). Ocelli, none ; anterior wings
very broad ; posterior margin, sub-falcate.

Genus Chrysopa (Leach). Ocelli, none ; wings, entire ; anten-
nae, cylindrical ; labrum, notched.

Genus Hemerobius (Linn.). Ocelli, none ; wings, entire ;
antennae, sub-moniliform ; labrum, entire.

Genus Coniopieryx (Curtis). Tarsi, five-jointed ; wings covered
with white powder ; few nerves ; nerves disposed nearly alike in
all wings ; labial palpi terminated by large ovate joint.

Mr. Moseley, of Huddersfield^, arranges the Neuroptera as
follows : —

Order, NEUROPTERA.

Sub-Orders, Trichoptera (Caddis flies) ; Planipennia.

Families. — PanorpidcB. (Scorpion flies).
Hemerobiid(B (Lace-wings).
Raphididce (Snake flies).
Sialidce (Alder flies).

Sub-Order, Pseudo-Neuroptera.

Families. — Libeliulidce (Dragon flies).
Ephemeridce (Day flies).
PerlidcB (Stone fly).
Psocidce (Book-mites).

Moseley says : — " This order of arrangement is exactly the
reverse of that given by the British authority (McLachlan) on
these insects. The Trichoptera are so inseparably connected with
the Lepidoptera, and the Psocidce so much resemble the Ort/ioptera,
that under the present disposition of the orders 1 have been com-
pelled to adopt this course."

Referring to the Heinerobiidce he says : — " The members of the
genus Chrysopa are of largish size, delicate green with light gauzy
wings, and bright brassy eyes. The species of the genus Hemero-
bius are small insects, blackish or huffish, and wings very
iridiscent."

Dr. Hagen, whose series of Synopses of the Neuroptera are
standard, gives thirty-two species of the Hetnerobiidce. as British,
and classifies them as follows : —

404 PREDACIOUS AND PARASITIC

Family He7nerohiid(E.

Genus Osmylus (i species). — O. Chrysops^ a pretty brown
insect, with the wings spotted with black. It is met with in the
month of June, and seems to prefer stony, rapid streams, fringed
with alders. The larva lives partly in water. In this genus there
are ocelli visible.

Genus Chrysopa (15 species). — In this genus the ocelli are
wanting. The larva feeds on aphides.

Genus Sisyra (2 species). — The larva lives in water, and has
been described by Westwood under the name of Bratichiosioma
spongillcB.

Genus Micromus (3 species).

Genus Hcmerobius (7 species). — The larvae of the species of
this genus preys on aphides, and clothes itself with the empty
skins of its prey.

Genus Drepaiwpteryx (1 species).

Genus Coniopteryx (3 species). — These are small and covered
with a white mealy powder. The larvae live in fir trees, the
aphides frequenting which are their food.

Mr. W. S. Dallas removes the Dragon flies to the Orthoptera^
and arranges his Neuroptera as follows : —

Order, NEUROPTERA.

Sab-Order, Planipennia.

Families. — Megaloptera (including sub-family Hemerobiidce),

SialidcB (Alder flies).

PanorpidcB (Scorpion flies).
Sub-Order, Trichoptera (Caddis flies).

Mr. Dallas describes the Hemerobiidcb as having " antennae
either thread-like or necklace-like and not clubbed."

Chrysopa he describes as a delicate green insect, about half-an-
inch long, with gauzy wings traversed by a most delicate network
of green veins. The prominent eyes are of a beautiful golden
colour.

Mr. R. McLachlan, in his " Monograph of the Neuroptera^'''
published in the Transactions of the Entomological Society for 1868,
classifies the Neuroptera Planipennia as follows : —

ENEMIES OF APHIDES. 405

Division I. — Sialifia (Alder flies).

,, II. — Hemerobiince (Lace-wings).
„ III, — PanorpidcB (Scorpion flies).

HemerobiincE, he divides into three families : —

Family I., Hcfnerobiidce. — Antennae moniliform ; wings mostly
with numerous transverse veinlets ; margins ciliated.

Family II., Coniopierygidce. — Antennae moniliform ; wings,
scarcely any ; transverse veinlets ; margins not visibly ciliated,
minute ; covered with whitish powder.

Family III., Chrysopidce. — Antennae setiform ; wings with
moderate number of transverse veinlets ; margins ciliated ; colour,
usually greenish.

The family Hemerobiidce, Mr. McLachlan divides into seven
species, of which two, or perhaps three, are aphidivorous, as
follows : —

^i. — Osmylus (i species), not aphidivorous.

2.—Sisyra „ „ „

3. — Psedra (4 or 5 species) ,,

4. — D^'epanopteryx (i species), aphidivorous.

5. — Hemerobius (13 species) „

6 . — Megaloniiis.

7. — Micromiis. Larva very probably aphidivorous.

The Aphidivorous Genera are divided by him as follows : —
Drepanopferyx. — i species, D. PhalcEuoides (Linn.).
He77ierobiiis. — H. elegans (Stephens).

,, H. pelliicidiis (Walker).

,, H. i?ico7isp€chis (McL.), Fig. 6.

„ ff. niiudulus (Fabr.), Fig. 7.

,, H. micans (Olivier), Fig. 8.

,, H. humnli (Linn.), Fig. 9.

,, H. ?narginati4s (Stephens), Fig. 10.

,, H. limbatus (Wesmael), Fig. ii.

,, H. pint (Stephens).

,, B. Atrifrofis (McL.).

,, H. snb?iebulosis (Stephens), Fig. 12.

„ H. nervosus (Fabr.), Fig. 13.

„ H. Concinnus (Stephens), Figs. 14, 15.

406 PREDACIOUS AND PARASITIC

To assist in recognising these, I have availed myself of the
drawings, given by Mr. McLachlan, of the final segments of the
abdomen of the male in several species, and of both male and
female in one species. These will be found highly characteristic,
and entomologists are much indebted to Mr. McLachlan for plac-
ing at their disposal such definite features in so clear a manner.

The ChrysopidcE the same naturalist has divided into two
genera : —

I. — Chrysopa (Leach). 2. — Notochrysa (McLachlan).

The genus Chrysopa comprises the following species : —

Mostly green, often with black ) C. Flava (Scop.).

markings - - -] C. vulgaris (Schneider).

Ditto

do.

do.

C. Aspersa (Wesmael).

Ditto

do.

do.

C. ventralis (Curtis).

Ditto

do.

do.

C. septem pmidata (Wesmael).

Ditto

do.

do.

C, flavifro7is (Brauer).

Ditto

do.

do.

C. vittata (Wesmael).

Ditto

do.

do.

C. alba (Linn.).

Full green

colour -

-

- C. phyllochroma (Wesmael).

Ditto

do.

-

- C. abbreviata (Curtis).

Blue-green

I

-

- C. per la (Linn,).

The genus Notochrysa consists of two species only, but these

are remarkable for their colour : —

Dark, reddish orange, black, ") iVi/^^/^^V^/>^ (Stephens),
fuscous, and yellow - -] N. capitata (Fabr.).

The Cofiiopterygidce consist of one genus only [Co?iiopteryx),
and it includes but three species : —

C. Psociformis (Curtis) ',
C. Tineiformis (Curtis) ;
C. Alcyrodiformis (Stephens).

This is the most complete classification of the Aphis-eating
Neuroptera with which I am acquainted, and, save for some con-
fusion in the characters ascribed to the main groups, there cannot
well be a more satisfactory arrangement of the species found in
Britain. The larval forms are of great interest, and, being com-
paratively little known in many cases, offer an attractive field for
investigation to any observer who may have time and opportunity
to study their Hfe-histories.

Journal of MicroGCODv 3'^.^Ser. Vol 5. Plate 18.

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ENEMIES OF APHIDES. 407

EXPLANATION OF PLATES XVIII. & XIX.

j»

»>

»>

Plate XVIII.

Details of Aphidivorous Hemerohiince.

Fig. 1. — Maxillary palpus of Larva of Hemerohius, showing the pecu-
liar chitinous incomplete rings.

2. — Mandible of same larva, exhibiting the toothed termination
and the fine serrations of the edge.

3.— Maxilla of same. The opening at the extremity through
which the juices of the aphis victims are ingested is clear,
and also the fold extending longitudinally down the organ.

4. — Labial palpus of same larva, showing in the widened termi-
nal joint the same arrangement of incomplete rings of chitin.

These organs are much smaller than the similar organs of
Chrysopa perla, shown in PI. XII., but are magnified in a
much greater degree.

5. — Threads of silk-like substance, spun by the same larva to
form its cocoon. These threads were spun on a cover-glass,
and the glutinous nature of the secretion is clearly visible at
the points of attachment. No indication of duplication or
structure of any kind is visible.

,, da. — Portion of same, more highly magnified.

,, 6. — Extremity of abdomen of ^ Hemerobius inconspicuous.

,,7. — ., >} ^ H. nitudulus.

,,8. — ,, „ ^ H. Micans.

,,9. — ,, ,, 6 H. hitmuli.

,,10. — ,, ,, 6 H. marginatus.

,,11. — ,, ,, 6 H. liynhatus.

„ 12. — ,, ,, c? H. subnehulosis.

,,13. — ,, ,, 6 S. Nervosus.

,,14. — ,, ,, ? -ff • Concinnus.

,,15. — ,, ,, S H. Concinnus.

The last 10 figures are after those given as characteristic
by Mr. R. McLachlan in his Memoirs on the Neuroptera.

Plate XIX.

Fig. 1. — The wing venation of Chrysopa perla, after Bowerbank, in
the Entomological Magazine, showing the circulation through-
out the nervures. The arrows show the direction taken by
the fluids within.

,, 2. — A branching vein, showing the manner in which the included
trachea divides.

408 ENEMIES OF APHIDES.

Fiofs. 3 and 4. — Veins showing the ringed tracheae within. The dia-
meter of the tracheal tube is about 2 2V2 ^"' 5 ^"^^^ ^^ ^'^^ ^^^'^
is about 4^g in.

,, 5. — Wing of the male of a smaller species of Chrysopa, drawn
directly from the insect.

,, G. — Wing of Hemerobius, drawn under the same conditions as the
last figure, illustrating the differences in structure and
venation.

, , 7 — Antenna of Chrysopa perla. consisting of a very large number
. of similar cylindrical joints.

8. — Antenna of Hemerobius, exhibitingr the moniliform structure.

Cbange of Hir.

THE necessity for change of air not only during convalescence
from illness, but as a means of maintaining the normal
standard of health, is now generally recognised. The father
of a family who fails to make some arrangements for giving his
children an annual holiday, either at the seaside or elsewhere, is not
acting judiciously. Young people who live in large towns and who
have comparatively little opportunity of indulging in outdoor games,
and getting healthful exercise, soon " run down " and become
depressed and debilitated. Many people seem to think that a pre-
liminary illness is requisite as a justification for a holiday, but there
can be no doubt that there would be very much less illness if
change of scene and air were regarded as necessities of life. One
annual outing is not enough for the maintenance of robust health,
but should be supplemented by excursions five or six times a-year.
People are waking up to the absolute necessity of varying their
ordinary daily toil with periods of relaxation. English people are
energetic enough in what concerns business matters, but as a rule
take their pleasures sadly, which may possibly arise from the feeling
that they are doing something unusual. The breadwinner of a
family who cannot take a holiday in the summer should set aside a
weekly sum as a nucleus of a " pleasure hoard " to be devoted to
recreation. A man with an assured income of ^300 is justified in
spending 5s. weekly for this object, which would give a family each
week's end invigorating exercise in the fresh air. When a holiday
is taken the programme should be minutely worked out before, or
there will be loss of valuable time. Trips arranged systematically
every week not only afford a vast amount of pleasure, but obviate
resorting to the doctor and the chemist. — " T/te Faftiily Physician''

[409]

^be Hacomijcetc^.''

THE fourth volume of this comprehensive work on British
Fungi is devoted to the Ascomycetes, and with the kind
permission of Messrs. George Bell and Sons, we purpose
making one or two short extracts.

The very large number of species of fungi included in the
group known as the Ascomycetes are characterised by having their
spores produced in asci^ or mother-cells. In the great majority of
species the asci are numerous, closely packed side by side, and
form the disc or hymenium^ seated on and protected by a structure
called the ascophore^ which is either parenchymatous — that is, com-
posed of a mass of more or less polygonal cells, united to form a
tissue — or consists of densely interwoven septate hyphae.

The Ascomycetes are divided into the following families, viz. :
Gymnoascaceae, Hysteriaceae, Discomycetes, Pyrenomycetes, and
Tuberaceae.

For our first plate in illustration of this work we have chosen
that representing the second family : —

HYSTERiACEiE (Plate XXI.).

Ascopores erumpent, innate, or superficial ; horizontally ellip-
tical or linear, or vertical and laterally compressed ; texture carbon-
aceous or membranaceous ; dehiscing by a narrow slit running the
entire length of the ascophore, black or blackish- brown ; asci 4—8
spored ; spores hyaline or coloured, continuous or septate ; para-
physes usually present. The species are all minute, and mostly
gregarious ; all are saprophytes, growing on old wood, bark, and
also on dry leaves.

Explanation of PI. XXL, showing Figures illustrating the
Hyste7'iacece, etc. — Fig. i, Lophium mytillinum^ Fries, a group of
plants, nat. size. — Fig. 2, one ascophore ; slightly magnified. —
Fig. 3, ascus and paraphysis ; highly magnified. — Fig. 4, spores of

* British Fungus Flora : A Classified Text-Book of Mycology. By
George Massee, author of '' Plant Life," " The Plant World," etc. Vol. IV.
Cr. 8vo, pp. viii. — 522. (London: Geo. Bell & Sons. 1895.) Price 7/6.
We thank the publishers for the loan of the electros, from which the accom-
panying plates are printed.

International Journal of Microscopy and Natural Science.

Third Series. Vol. V. dd

410 THE ASCOMYCETES.

same; x 300. — Fig. 5, Farlowia repanda^ Sacc, group of plants,
nat. size. — Fig. 6, one plant of same, slightly magnified. — Fig. 7,
Section of same ; slightly magnified. — Fig. 8, Ascus and paraphy-
ses of same, highly magnified. — Fig. 9, Spores of same; x 300. —
Fig. 10, Dichcena quercina, Fries; nat. size. — Fig. 11, Ascus and
paraphyses of same ; the spores should not be muriform, as repre-
sented, but 3-septate ; highly magnified. — Fig 11a, Spores of
same; x 300. — Fig. 12, Spores of DichcBna faginea^ Fr., var.
caprece ; x 300. — Fig. i2>i Hysterium puHcare, Pers. ; nat. size. —
Fig. 14, One plant of same, seen from above; shghtly magnified.
— Fig. 15, Ascus and paraphysis of same ; highly magnified. —
Fig. 16, Spores of same; x 300. — Fig. 17, Actidiwn hysterioides,
two plants; slightly magnified. — Fig. 18, Free spores of same ;
X 300. — Fig. 19, Ascus of same ; highly magnified. — Fig. 20,
Group of plants of same; nat. size. — Fig. 21, Schizothyriiun ptar-
micm, plants on a living leaf oi Achillea ptar?ntca; nat. size. — Fig. 2 2,
Plants of same on portion of a leaf; slightly magnified. — Fig. 23,
Ascus and paraphyses of same ; x 300. — Fig. 24, Schizoxylon
Berkeley a7ium^ portion of a spore, breaking up into cells at the
septa; x 750. — Fig. 25, Ascus and paraphyses of same; x 300.
— Fig. 26, One plant of same, slightly magnified. — Fig. 27, Plants
of same on dead stem; nat. size. — Fig. 28, Ephelina radicalism
Mass., showing the blackened swelHng on the stem of Rhinatithus
caused by the fungus; nat. size. — Fig. 29, Ascus and paraphyses
of same ; x 300. — Fig. 30, Stylospores of same ; x 300. — Fig.
31, Ostreion Ajtiericanum, Duby, spore; x 300. — Fig. 32, Hys-
terographiwn fraxini^ group of plants ; nat. size. — Fig. 2)'h^ Spore
of same, x 300. — Fig. 34, Ocellaria aurea, Tul., group of plants
bursting through the bark of a branch, slighdy magnified. — Fig.
35, Ascus and paraphyses of same ; x 300. — Fig. 36, Gloniopsis
curvaia^ Sacc. ; nat. size. — Fig. 37, Ascus and paraphyses of same;
highly magnified. — Fig. 38, Free spore of same ; highly magnified.
— Fig. 39, Nytilidion Iceviuscuhini, Sacc, group; nat. size. — Fig. 40,
One ascophore, slightly magnified. — Fig. 41, Free spores of same;

X 300. — Fig. 42, Xylographa parallela. Fries., three plants seen
from above; slightly magnified. — Fig. 43, Sections of same;
slightly magnified. — Fig. 44, Ascus and paraphyses of same ;

X 300. — Fig. 45, Aulographum vagum^ Desm., plants on portion

PL. XXI.

Figures illustrating the Hysteriacea, etc.

PL. XXII.

Figures illustrating the Helvellece, etc.

THE ASCOMYCETES, 415

of a leaf of goat-willow ; nal. size. — Fig. 46, Two plants of same,
slightly magnified. — Fig. 47, Ascus and paraphyses of same;
X 300. — Fig. 48, Pseiidographis pinicola^ Rehm., plants ; nat. size.
— Fig. 49, One plant of same ; slightly magnified. — Fig. 50, Ascus
and paraphyses of same; x 300. — Fig. 51, Colpoma degenerans,
Mass. ; spores x 300. — Fig. 52, Propolis fagmea, Karst., group of
plants; nat. size. — Fig. 53, Two plants of same; slightly magni-
fied.— Fig. 54, Section of same; slightly magnified. — Fig. 55,
Ascus and paraphyses of same; highly magnified. — Fig. 56, Free
spores of same ; x 300.

Discomycetes.

The most important distinctive feature of the present great
group or third family of the Ascomycetes consists in the disc or
hymenium being fully exposed at maturity. There is a very wide
range in size, form, texture, and colouration, and, as would be
expected, there are transitions to allied groups at various points.
We have selected for our second plate that illustrating the

Helvelle^e (Plate XXII. ).

The principal common feature of this group is that the disc or
hymenium is fully exposed from the earliest stage. There is an
absence of the incurved margin of the ascophore when young, and
the gradual exposure of the disc so characteristic of the Pezizae.

Explanation of Plate XXII., showing Figures illustrating

the Ifelvellece, etc.

Fig. I, Morchella esculenta^ Pers., entire fiingus ; about one-
third nat. size. — Fig. 2, Ascus and paraphysis of same ; highly
magnified. — Fig. 3, Spores of same ; x 330. — Fig. 4, Rhizina
undulata, Fries, entire fungus about one-half nat. size. — Fig. 5,
Section of same, showing the numerous rhizoids ; about one-half
nat. size. — Fig. 6, Ascus and paraphyses of the same ; highly mag-
nified.— Fig. 7, Spores of same, x 300. — Fig. 8, Gleoglossum
glutinosum, Pers., entire fungus ; about two-thirds nat. size. —
Fig. 9, Ascus and paraphyses of the same ; highly magnified. —
Fig. 10, Spores of same ; x 300. — Fig. 11, Leptoglossum micro-
sporuniy Sacc, ascus and paraphysis; highly magnified. — Fig. 12,
spores of same ; x 300. — Fig. 13, Gleoglossjcm viscosum^ Pers.,

416 THE ASCOMYCETES.

paraphyses highly magnified. — Fig. 14, Gyromitra esculenta^Ynts,
entire fungus; about one-half nat. size. — Fig. 15, Spore of same,
X 300. — Fig. 16, Gyromitra gigas, Cooke, spore; x 300. —
Fig. 17, Helvella crispa^ Fries, entire fungus; about one-half nat.
size. — Fig. 18, Spores of same; x 300. — Fig. 19, Verpa digi-
taliformis^ Pers., entire fungus ; about two thirds nat. size. —
Fig. 20, Section of pileus and upper part of hollow stem
of same; about two-thirds nat. size. — Fig. 21, Ascus and
paraphysis of same; highly magnified. — Fig. 22, Spathularia
Jlavida, Pers., entire fungus; about two-thirds nat. size. — Fig. 23,
Free spore of same; x 300. —Fig. 24, Ascus and paraphy-
ses of same; highly magnified. — Fig. 25, Leotia lubrica, Pers.,
single plant; about two-thirds nat. size. — Fig. 26, Section of
pileus of the same; about two-thirds nat. size. — Fig. 27, Ascus
and paraphysis of same ; x 300. — Fig. 28, Free spores of same •
X 300. — Fig. 29, Mitrula paludosa^ Fr. ; about two-thirds nat.
size. — Fig. 30, Ascus and paraphyses of the same; x 300. —
Fig. 31, Morchella conica, Pers., var. deliciosa, Fr., fungus; about
two-thirds nat. size. — Fig. 32, Vibrissea truncorum, Fries, group of
plants ; nat. size. — Fig. 33, Section of pileus of the same, showing
the spores escaping; shghtly magnified. — Fig. 34, Portion of a spore
of same; x 750. — Fig. 35, Ascus and paraphyses of same;
highly magnified. — Fig. 7,6, Peziza ochracea^ Boudier, two plants ;
nat. size. — Fig. 37, Ascus and paraphyses; highly magnified.

Secretions in Plants. — M. Tschirch announces in the
Botanisches Centralblatt that in all the normal cases in which he
has been able to study the formation of a secretion, he has found
that it was a function, not of the protoplasm, but of the cellular
wall. In the oil-glands of the labiates, composites, etc., the
secretion is due entirely to an internal layer of the cellular wall,
and the same is the case with the Papilionaceae. The secretions,
however, are never produced by the metamorphosis of the sub-
stance of the cellulose itself. The observation applies likewise to
the resins, which M. Tschirch considers as aromatic acid com-
pounds with a particular group of alcohols, which he calls resinols.
— Scie?ttific American.

[ «7 ]

Bacteria of tbe Sputa an& Cr^ptogamic
Jflora of tbe riDoutb.

THIRD MEMOIR.

By Filandro Vicentini, M.D., Chieti, Italy.

On Xeptotbiij IRacemosa* Plate xx.

Translated by Professor E. Saieghi.

NEW RESEARCHES ON THE FRUCTIFICATION OF THE
NORMAL PARASITE OF THE MOUTH

(LEPTOTHRIX RACEMOSA?)

I TRUST it will not appear too pretentious on my part if I
propose for such an isolated form — or, better to say, for the tiny
plant which thrives (and appears to germinate and fructify) — on
our teeth, taken as a whole, the name ol Leptothrix racejnosa, instead
of that of Leptothrix buccalis ; and this solely on purpose to qualify
it better, if it be true that the cryptogamic species must take their
name and character from the fructification (if any) rather from the
inferior or rudimentary appearances of their single particles, inci-
dentally incomplete, scattered, or isolated.

In describing the various aspects of the fructification in ques-
tion, we shall endeavour to group them in such a way that,
according to our view, there may be a better connecting of the
varieties ; but, in doing so, we do not wish to prevent a more
matured judgment.

Various Elements and Aspects of the Bunches.

To understand the various aspects which the ears or bunches
of Leptothrix racemosa present, we must value the different con-
stitutive elements of those clusters, which, according to our
observations, we consider to be four, in their natural order of
development.

The principal element, from which the other three proceed and
upon which they are formed, is the fertile filament, generally
slender, pale, containing internal parietal gemmules, invisible in

418 BACTERIA OF THE SPUTA

the iodine solution (simple or acidulated), but distinct enough in
gentian violet. For this kind of stalks we refer to the preceding
memoir. Then is it not strange that these fertile filaments should
be so slender, whilst the severed or truncated {^Bacillus buccalis
maximiis and Leptothrix buccalis fiiaxima of Miller) appear much
thicker and with a strong iodine reaction. We attributed this
thickness, or woody state, to the retrocession of the germinal
matter, somewhat analogous to the action of the saps in pruning-
plants. Our parasite, being a vegetable, or rather a tiny plant,
and having to be studied as such, according to Dallinger,* it is
natural that the form of its stem should resemble that of the cone.
The stalk being, in fact, the proper organ of vegetation, destined
to support the upper organs, it is natural that the lower part
should be stronger and that it should get thinner towards the top,
which, finally, must bear the fruits. It is identical with the
process of other plants.

However, whilst this is the general rule, we shall see, as we
proceed, that certain fertile filaments become rather an exception,
thinning themselves similarly on the top ; but afterwards, on
reaching the base of the future fructification, they thicken in the
shape of a cylindrical club, colouring brilliantly with aniline, but
pale like the rest in iodine solution. We shall speak later on of
the probable meaning of this swelling of the stalk, recalling only
on this subject the other apical swellings, already mentioned and
delineated in the preceding Memoir (Fig. 9, b, c).

To this first element (the internal stem) follows in order of
formation the second, of peduncles or ingrafting threads, destined
to bear the spores, like the sterigmata of many fungi. Such
peduncles are very pale, invisible with less powerful objectives, but
very distinctly observable (under certain conditions) with the
1/2 5th power just mentioned. They are short, funnel-shaped,
with a point on the stalk and the opening towards the spore. In
the young ears, being yet deficient or scanty in the secretion of
the viscid substance, the peduncles are more visible ; whilst in
the older ones they remain more or less opaque.

* Dallinger, TJie Microscopical Organisms atid their Relations to Disease
(Journal R. M.S., i88s).

AND CONTENTS OF THE MOUTH. 419

The spores constitute the third element, and are of globular
form ; pale in iodine solution, more or less coloured in the aniline.
They are smaller in the younger clusters, on which, for this very
reason, the peduncles or sterigmata are more discernible ; whilst,
the spores becoming afterwards larger and covered with a more
viscid substance, the peduncles remain hidden. Besides, the spores
are not equally thick in all the fructifications ; but where the spores
are thinner, as in Fig. 23, a^ there the details mentioned are more
visible. The little or non-visibility of the peduncles may result,
not only from the opacity produced by the abundance and density,
or from the heavy colouring of the viscid substance, but even,
where this is thin and transparent, from the identity of the index
of refraction of the two elements.

The fourth element is the viscid substance or glair, which we
hold to be the last to form. It proceeds from a sort of oozing or
secretion of the stalk or of the spores themselves, for, in the
younger ears, with yet small spores, it appears thinner and
indistinct.

And these are the fructifications which exhibit a more striking
resemblance to real clusters, either in the solution of iodine or
when they are very slightly affected by gentian violet. On the
other hand, in the ears with an internal swelling of the stalk, the
size of the spores, as well as the density and colouring of the
viscid substance, reach the highest degree, as we shall see later on.
That the viscid substance may proceed from the filament is
exhibited by the cited examples, in other species, by Billet, as well
as in our parasite, by those filaments of Leptothrix buccalis maxt?na
and oi Bacillus buccalis max imus, which, with the new i /2 5 th obj ective,
appear thoroughly enveloped in a hyaline sheath. That it may
proceed from the spores is shown by the example of the incapsu-
lated diplococci. However, between the exudation of the old
filaments and that of the ears there is this difference : that the
first has greater affinity for the acidulated solution of iodine, in
which it is better discerned, and the second for the gentian violet.

Keeping in view, on one side, these various elements, and, on
the other, the degree and different nature of the colouring, we may
fully explain the varied aspects of the fructifications.

Concerning the gathering and the preparation of the patina

420 BACTERIA OF THE SPUTA

dentaria and its treatment with the aniline colours, or with the
solution of iodine, there is little to add to what has been said in
the previous Memoir. We gave there the precise rules, in order
to obtain from the patina dentaria the greatest possible number of
fructifications, taking it before a meal or early in the morning.
We found afterwards that the fructifications are more abundant on
teeth with a thin film of tartar, particularly in the superior eye-
teeth. About the disintegration and colouring of the clods we
refer to what has been said. For the acidulated solution of iodine,
we placed on the slide, first, a small drop of lactic acid, disin-
tegrating in it afterwards the patina, and lastly adding to it one or
two drops of solution of iodine. It generally takes a quarter of
an hour to get a proper colouring.

In the preceding Memoir we suggested that the superfluous
liquid should be allowed to trickle down from the sides, after
applying the cover-glass ; but afterwards we discovered that it was
better to let most of the liquid evaporate before applying the
cover-glass, so as to avoid the wave of liquid caused by the pres-
sure, which might remove many bacteria and bacilli and several
isolated filaments and clusters set free from the tiny islands that
often supply the most instructive specimens ; blotting paper would
also take up many of the specimens. To eliminate the air-bubbles
keep the cover-glass on edge (straight up) with the two first fingers
of the left hand, so as to form an acute angle with the slide, at
two centimetres from the preparation ; then with a straight needle,
held in the right hand to support the glass, and with a bent needle
pushing it on the specimen, lower it down gently on to the edge of
the preparation, when the air-bubbles will be set free.

If we wish to institute a comparison between the two stains
adopted in this work, we may say that gentian violet colours
briskly the little spores, but at the same time attacks and obscures
the viscid substance, so that, wherever it fully invests, the peduncles
or sterigmata are either not seen at all, or may hardly be distin-
guished. This happens even by applying very little tint. Never-
theless isolated fructifications slightly affected by the tint may some-
times be found in the preparation, and it is just upon one of these
occasions that we first detected the peduncles in question. For
this reason, the whole image, either of the single fructifications, or

AND CONTENTS OF THE MOUTH. 421

of their branching filaments, is better seen in the anilines (see in
the previous Memoir the Figures lo, 12, 16) ; the solution of iodine
would hardly give the same result. This solution has little or no
action upon viscid matter ; therefore, the fructifications assume
with it a granular aspect, and if the spores are not too thick it
shows the peduncles better ; also because the solution of iodine
acidulated with lactic acid attacks relatively better the peduncles
themselves, whilst the gentian violet invades them less than other
elements. Consequently it happens that the solution of iodine
better exhibits the complex aspect of the clusters or the truncated
sterigmata. (See Fig. 23, d.) It has, however, the disadvantage of
not satisfactorily allowing the use of powerful eye-pieces, thus
limiting the enlargements ; whilst in the fructifications stained
with gentian violet, the details of structure may be (under favour-
able conditions) detected even with a No. 6 eye-piece, as is shown
in Fig. 24, magnified to 3,100 diameters.

Now from the concourse of these various circumstances, either
relative to the age of the single fructifications, and to the more or
less thickening of peduncles and spores, or to the quality and
degree of the colouring, we are able to obtain images conspicuous
in the whole, but with peduncles only partially or not at all visible,
or sometimes less conspicuous in the whole, but with quite dis-
tinct peduncles. The necessary conditions to the clear vision of
the peduncles in question may be summed up in the following
series : — ^, proper optical instruments ; b^ clusters still young ; c,
rather thin spores ; d, a weak gentian violet ; or <?, solution of
iodine. We have already said that the best images are obtained
from isolated fructifications fallen from clods in a clear field, and
it is our intention in this work to consider the two colourings above
mentioned, apart from the use of other tints.

The fructifications in question can be observed by axial illu-
mination or by oblique light. The best images of the clustered
forms and of the single sterigmata are obtained by axial illumina-
tion by properly adjusting the correction collar, and by centering
the iris diaphragm and the Abbe condenser along the optical axis.
On the other hand, the general relief of the ears and the position
of the spores in six longitudinal series, are better detected by
oblique light, by pushing aside the diaphragm and letting it after-

422 BACTERIA OF THE SPUTA

wards go round the optical axis, or substituting for it the dark
diaphragm, pushed on one side, and making the stage rotate with
the upper part of the instrument round the same axis. In the
latter case, a better effect is obtained when the ear is horizontally
disposed and is sti-uck from behind by the pencil of light, almost
parallel with the stalk, beginning from the root, so that the
luminous rays run along its axis. Then, focussing, the general
effect of the six series of spores becomes striking, the whole ear
takes a beautiful mulberry appearance, of which it is impossible
to give a satisfactory representation.

The figures which we have drawn are, however, sufficient to
give a proper idea of the peduncles in question. In Fig. 23, «, we
have represented a short and young ear, as seen stained with the
acidulated solution of iodine, magnified to 1,700 diameters; in it
the spores are thin, and its clustered form is most striking, as we
can even perceive posterior rows of little spores. In c (same
figure) is seen an older ear, thicker and longer (same staining,
and magnified 1,170 diameters) in which, however, the peduncles
are sufficiently distinct. In d^ then (same staining and magnifica-
tion), is drawn a short fragment of a fertile stalk, found by chance
in one of the numerous preparations ; only two spores are seen at
its base, and higher up the peduncles still thick, but without
spores ; the rest of the ear is wanting."^' In the above Fig. 24
(weakly stained with gentian violet, magnified to 3,100 diameters)
the spores are intact, their funnel-shaped peduncles are visible
through the viscid substance, moderately stained. The stalk
exhibits several gemmules of reserve.

The facts hitherto given (in support of the arguments
expounded or simply suggested in the preceding Memoir), which
everybody can verify for himself, are, in our opinion, sufficiently
conclusive to warrant us in affirming the existence of a really
external sporification or fructification of the normal parasite of the
mouth upon six longitudinal series of peduncles and spores. But
for a more evident proof, take the specimen drawn in Fig. 25.
This specimen, obtained by pure chance, amongst the number-
less preparations examined, represents a stalk which, emerging

* The attenuated appearance of this stalk probably depended upon a flowing-
out of its sap or germinal matter owing to rupture.

AND CONTENTS OF THE MOUTH. 423

from the materia alba or heap, was extending horizontally, and
changed abruptly for an upward direction, with the upper part
bearing the cluster. It is seen much aslant, but fortunately in-
tact (stained with acidulated solution of iodine, and magnified
to 1,700 diameters); it has a round end, with a fine rosette
of six rays, formed by six terminal sterigmata, and having the
six last spores, probably yet unripe, to their tops.

Fructifications by Temporary Spores {Sporids ?) and
BY Persistent Spokes {Teleutospores}).

The mycetologists and the algologists call temporary spores
agamic spores, sporids, and conids the spores which are formed
without previous fecundation, and are intended by the multiplica-
tion of the species in more favourable and immediate conditions
(namely, the conids of the Feronospora, destined to diffuse the
species during a part of the year) ; whilst the persistent winterly
spores, oospores, or teleutospores, are produced by the act of con-
jugation, and help to preserve the species from external injuries,
and to strengthen their future shoots (like the hybernating spores
of the Feronospora in the thickness of the hospitable parenchyma,
deputed to reproduce the species in the following year). Of the
two processes of sporification, one (says De Bary) seems intent
upon preserving intensively the species through conjugation, the
other only to increase its extension.^

Of the other processes of propagation through gemmules,
sprouts, etc., we have already treated in the previous Memoir, and
shall refer to the subject again later on.

All the fructifications of our parasite, hitherto described and
drawn, probably belong to the temporary series, with the excep-
tion of the specimen given in Fig. 13 of the preceding Memoir,
which might be included in the persistent series ; but from the
last researches and other isolated cases, of which we will speak
presently, it appears that the same parasite presents also a com-
paratively scanty number of fructifications of another kind, which,
although similar in shape or type, assume special characteristics, so
that we are rather inclined to refer them to the persistent series.

* De Bary, Dti Developpement des champignons parasiiaires (Ann. des
Scien. Nat. Sir. Bot., t. XX.).

424 BACTERIA OF THE SPUTA

We have already mentioned the club-shaped stems, two of
which, stained with gentian violet, are seen drawn in Fig. 26,
magnified to 1700 diameters. The club is generally long enough,
as in a ; but sometimes we meet short ones, as in d, which might
be called an incipient phase. In the first named specimen, the
club, although complete, is still quite bare, and, to all appearances,
represents a hardly-formed expansion, before the sterigmata and
the spores have germinated. In fact, in the Fig. 27 (same staining
and magnification) may be noticed an ear, on the whole larger
and with spores proportionally more conspicuous, exhibiting an
internal stem, club-shaped, and brilliantly coloured, quite dissim-
ilar from the pale and slender stems of the first series, but
analogous to the bare stem of Fig. 26.

To our knowledge, these ears never reach the length of some
others having slender stems (see Figs, 12 and 16), which may
depend upon the comparatively limited length of the club-shaped
expansions. The spores of such ears are, besides, more conspic-
uous and pressed together, so as to form on both sides a sort of
zone or violet aureola, at a little distance from the stem ; and,
between this and the periphery, runs a clearer intermediate zone,
where the viscid substance is less coloured, but yet capable of
disguising the sterigmata. The light proceeding from the con-
denser must, in fact, cross first the deep violet zone, which
is next the slide, then the intermediate clearer substance (the
index of refraction of which is identical perhaps with that of the
peduncles), and finally the opaque violet zone, which overlooks
the cover glass. At any rate, the result of this optical combination
is to hide the peduncles. When in the solution of iodine we come
across such ears, the zones become mixed up, and we perceive, on
the whole, a triplex series of coloured granules, as is shown in
Fig. 13 of the previous Memoir, incompletely represented, which
would lead to the supposition that in these ears the secretion of
glair is more abundant and thick. ^

It appears, besides, that such ears are even more compact and
resisting to the mechanical agents of disintegration ; also, their

^' After presenting this Memoir, we have made further researches (especi-
ally on the presence of such ears in the sputum of pneumonia, and on the manner
of detecting the peduncles), which we will soon make known.

AND CONTENTS OF THE MOUTH. 425

fragments always exhibit a cohesion of the single particles, and
their brilliant colouring becomes more conspicuous with aniline.
We remember having often found similar fragments in sputa ; but,
not then knowing their nature, we overlooked them. We also
remember that some sound ears, or fragments of the same, were
found mixed with many minute ears in fructifications upon small
flakes of urethral mucus, as we mentioned in the previous Memoir.
We may, however, state that, in the preparations of the dental
patina, ears of this sort are scanty in comparison with those of
the preceding form.

In considering now those more robust and conspicuous forms
of fructification, the mind tries, through analogy, to connect them
with the process of fecundation, and finds, although indirectly, its
existence is confirmed. In the preceding Memoir, we have des-
cribed some pseudo-inflorescences in tufts, having points varying
in shape and size, which we held to be future spindle-like bacilli
{Bacillus tremulus of Rappin) and future comma, or serpentine
bacilH, destined, after being dissevered from the stem and becoming
free, to perform the functions of spermatia or antherozoids. We
gave the reason for such hypothesis, as we also pointed out the
likeness of those elements (supposed male organs), with the sper-
matia of certain well-known fungi, like Sphcerella sentijta, Fumago
salicina, Apiosporium citri, etc.

The antherozoids or sperviatozoids in sea weeds, and the sperma-
tia in fungi were considered as elements of fertilisation. The
first {migratory filaments, spiral filaments, seminal corpuscles), now
cylindrical, now ribbon-shaped, furnished with cilia and endowed
with spiral movement in various directions, are originally contained
in a cellule or male organ {antheridium). The spermatia cor-
puscles, oval or in rods, straight or curved, also very motile, like
the analogous forms of the mouth, were, nevertheless, held to have
no cilia. They are originally sometimes contained in an appro-
priate cellule or male organ {spermogonium), sometimes they grow
freely on the apex of the filaments, and get dissevered simply
through disjunction. In our parasite we thought, at first, that the
fertilising elements belonged to this last type, and were formed in
a free state on the stems ; but we shall see, by and by, that perhaps
even they originate within apposite sheaths, and therefore may be

International Journal of Microscopy and Natural Science.
Third Series. Vol. V. eb

426 BACTERIA OF THE SPUTA

referred to the first type. In general, the spermatia, unable to
multiply through fission, have been seen, at times, to germinate
on their own account ; one common example of this kind is
exhibited in the ergot.

Now, we repeat, the existence of fructifications more conspic-
uous and distinct from the others (through their large club-like
stem and their two zones of colouring, etc.), in the normal parasite
of the mouth, would be quite explained, admitting them to possess
fertilising elements constituted by spindle-like, comma, and serpen-
tine bacilli, already described by us, and holding the other spores
as agamous and temporary. Perhaps the persistent spores in
this parasite are destined to go through the intestinal tube unin-
jured, withstanding the dissolving action of the gastric juices, and
emerge into the external world, maintaining in the faeces their
vitahty for the future diffusion of the species.

As regards the function of conjugation, it may be performed
on the already formed filaments, as we see in many other crypto-
gams, where sometimes the act takes place between two contiguous
filaments, the male organ of the one penetrating the female organ
of the other ; but nothing prevents us from believing that a ferti-
lisation of another kind may have taken place between the male
element (spindle-like, comma, or serpentine bacillus) and the
mother spore, before the germination of the fertile filament.

Against these views of ours, a quite opposite hypothesis might
be produced, namely, the hypothesis of a commensalism or sym-
biosis. In such hypothesis the small sporules, and especially the
productions by potJits, would not be proper phases of Leptothrix^
but parasites of the parasite^ or new micro-organisms of another
species, come to implant themselves and thrive at the expense of
the original parasite in the same way as Leptothrix parasitica^
Kiitzing, which with its slender filaments lodges itself on the larger
filaments of Zygnema and Cladothrix dichotoma, as we see in
Fig. 21 (stained with vesuvine and methyl violet, then with solution
of iodine, magnified to 600 diameters). But, in this way, one
might object, for argument's sake, that grapes are so many para-
sites of the vine on which they fructify. In fact, consulting the figure
in question, anyone can see that the secondary parasitical shoots,
Cj c, are less thick than our points, which engraft themselves round

AND CONTENTS OF THE MOUTH. 427

the stem, like the hairs of a bottle brush. They are not, besides,
methodically arranged, but stretch out very much, like stems des-
tined to vegetate on their own account, rather than to complete
the organism bearing them. The filaments of Leptothrix parasitica
implant themselves also upon the stem of Zygnema, a, a, or of
Cladot/irix, b, b, which feeds them, by means of bulbs, or spores
originated in them, s, s, as the Fig. 22 shows still better (same
staining, magnified to 1,600 diameters) : spores which are not
seen at all at the insertion of our points. And still less the fila-
ments of Leptothrix parasitica are seen to drop at last from the
central stem, and swim in the medium with the same briskness of
our spindle-like, comma, or serpentine bacilli.

Various Aspects and Forms.

In the preceding Memoir we have spoken of various forms and
appurtenances of the parasite in question ; we specially point out
the bifurcations and trifurcations towards the seat of certain fila-
ments, with tiny radical swellings, like haustoria; and then the
more pronounced ones, some at the knots, some at the apex : the
latter like small heads. We have already mentioned the other
apical swellings (fertile filaments), club-shaped.

We now go on to describe a third form of apical expansions,
very scarce, which, provisionally, we shall denominate sheath
expansion.

Such an expansion, represented in Fig. 28 (stained with gentian
violet, magnified to 3,100 diameters), is very pale, has streaks in
its contour, not detected with inferior objectives. Its paleness
cannot be attributed to insufficient colouring, because the examined
form rose on the top of a filament (likewise pale) in the midst of a
thick and very pretty tuft of ears brilliantly stained (of the
kind shown at Fig. 12), and nearly surpassed them with its
point. The external contour is very slender from the base of the
expansion up to its point, and between the internal stem and the
exterior contour are seen numerous slender, tiny, transverse
threads, which are attached to the external sheath by means of
more prominent small dots.

At first we could not understand the probable meaning of this
structure. That it was not to be taken for the club-like expansions

428 BACTERIA OF THE SPUTA

of Fig. 26 was evident from its paleness, being the antipodes of
the bright colouring of these, as well as the presence of the inter-
nal fine beams. On the contrary, after deeper reflection, we
thought we might refer it to other forms already described in the
previous Memoirs. One of these forms would be that of the pseudo
inflorescences in tufts (preceding Memoir, Fig. 14). Comparing
the two figures, it will not appear unlikely that the slender threads
of Fig. 28 in the present Plate, distended like fine beams between
the internal stem and the sheath, growing more and more in a
transverse direction, may end by breaking the external envelope and
become free /^/«/^, perfect fertilising elements (spindle-like, comma,
or serpentine bacilli), at first only free from the surrounding
sheath, in order to constitute the tufts of the preceding Plate, and
at last becoming disjoined from the central stem, so that they may
fulfil their function through that stirring motion, mentioned in the
previous work.

The other form, possibly analogous, would be that delineated
in the first Memoir (Fig. 2, ;/, lower down), similar to a large
bacillus, singularly veined throughout, and for a certain tract
having traces of lineal bacilli. Even this is a rather rare form,
and we have never found it on the top of any filament, but quite
by itself. We have already hinted in the previous Memoir that
that veined bacillus might be a sort of receptacle for the future
fertilising elements, as an antherid or a spermogone.

Now, supposing that interpretation true, the transmutation from
one to the other of the three forms would become clear enough.
We should have, in the first form (or sheath expafisioii) of Fig. 28
(present Plate) an antherid or spermogone, hardly shown,
and in the second form (the tufts of Fig. 14, previous Memoir) a
male organ in full development. The third form (the veined
bacillus of Fig. 2, ;/, below, first Memoir) would be an inter-
mediate form to the other two (an arrested form), or an antherid
or spermogone, prematurely fallen from its stem, having been
unable to attain to the adult form of tuft ; and then strayed from
its destination and remained, as it were, unripe, or even returned
to a neutral condition, which is, we think, common to the severed
or truncated filaments, as, having been unable to attain the fructi-
fication, they limit themselves to a reproductive function of a

AND CONTENTS OF THE MOUTH. 429

lower degree (fissiparous multiplication) through the increase of
the granules or the lineal minute elements, contained in the
interior of their sheaths. If this were confirmed by farther
researches, it would lead us to rectify the first supposition about
the formation of the fertilising elements. They would not form
themselves freely on the top of the respective filaments, but within
a receptacle or male organ properly so called, (sheath expansion).

These are only simple conjectures, aiming at connecting the
various forms hitherto described, reconducting the appurtenances
of our parasite to the general laws of the cryptogamic flora, and
far from pretending to give herewith a full and exact explanation of
them. We shall be quite satisfied if the features of the facts we
have endeavoured to describe can be proved by further researches.

But, even upon a simple descriptive ground, we should perhaps
overstep the limits of a simple preliminary study if we were to
dilate longer in the investigation of other particulars, before seeing
confirmed and set up the points already demonstrated (such being
the most important) by competent authorities. Neither is it our
business to solve the question whether the discussed parasite is a
fungus or an alga. We shall only say that it appears to us to
partake of the characters of both families, to thrive as an alga,
but to fructify similarly to certain fungi. We shall, therefore,
limit our remarks about some apparent irregularities, in the aspect
of the described ears, which, through inattention, might pass for
true irregularities or anomalies of structure.

In the first place, we refer to some gibbosities or irregular pro-
jections, which are met sometimes by the side or upon some ears,
which might lead to the belief that the ears themselves are perhaps
constituted without any order, or that the series or longitudinal
rows of the sporules are not always six in number, but at times
more.

Now, one of the more frequent causes of such irregular appear-
ance is very simple. The breaking up of a contiguous ear, and
the adherence of that extraneous fragment to the ear that we
examine ; having frequently verified this occurrence, we considered
it superfluous to draw a similar specimen on our plate. The
other case, less frequent, is drawn in Fig. 29 (saturated with
acidulated solution of iodine, magnified to 1,700 diameters).

430 BACTERIA OF THE SPUTA

Here it is not the superposition of an extraneous fragment, but
the folding up of the ear itself. In the figure referred to, the third
superior and the point b of the ear are turned up and pressed
back upon the middle third, but in a direction somewhat oblique
to its axis, so that, at first sight, or with inferior objectives, they
simulate a gibbosity. But focussing with the fine adjustment, it is
easily perceived that there is, in reality, a folding due to a mechan-
ical cause, and accidentally rendered even more pronounced by
the pressure of the cover-glass.

We do not speak of a third apparent irregularity, which might
deceive us only when using inadequate optical means — we mean
the accidental apposition of extraneous cocci, of bacteria and comma
bacilli around some ears, as shown in Fig. 23, b^ b. Under lower
power objectives, such cumuli or groups, especially if more con-
spicuous, may, in fact, simulate real protuberances.

There is, however, a special apposition of cocci and bacteria,
sometimes visible on certain ears ; perhaps, those remained longer
with their points in contact with the labial mucous, and there
became incrusted with the above bacterial elements, through a
cement of viscid mucus. Such ears, in fact, are never augmented
on the opposite side, but only on the top, like a very oblong pear ;
and the increase, gradually narrowing itself, seldom goes beyond
the half of their length (Fig. 30, stained with gentian violet, mag-
nified to 1,170 diameters).

When they reach the first colourising stage with the gentian
violet, we can easily perceive there is in reality a sort of cap (at
first, more pale and granular) constituted by cocci and bacteria,
only slighdy coloured, in various layers, towards the point «, and
sloping towards the half, a\ a ; whilst the ear, b, b, with its sporules,
is seen brightly coloured in the interior. In the second stage,
even these adventitious cocci and bacteria become coloured, and
the cap is no longer distinguished from the internal ear.

CONCLUSION.

We have seen how Billet describes the evolutionary cycle of
the Bacteriacese (which would constitute for our parasite only the
inferior cycle), and that his remarks mostly agree with those we
have made on the same parasite. His interpretations of the

AND CONTENTS OF THE MOUTH. 431

various phases of that cycle do not differ from ours, excepting in
what affects the production of bacteria included in filaments,
which Billet considers are real endogenous spores ; and we cannot
positively deny that such is the case in the four species studied by
him ; whilst in our parasite they ought, in our opinion, to be held
as simple gemmules of reserve.

But from the exposition of the facts in our previous Memoir,
and confirmed in the present one, it clearly results that the evolu-
tionary cycle, so nicely delineated by Billet, cannot include all the
morphological phases of our Leptothrix racemosa, but only some of
them. In this parasite, besides that first cycle which we call
inferior, there is another — the superior, which comprises the
organs of genuine reproduction and fructification. Finally, toge-
ther with these two normal evolutionary cycles, there is another
one — accidental, called virulent, in which (according to laboratory
experiments) it seems that certain elements, derived from the
parasite itself, may, as Pommay says, develop themselves in the
sense of virulence.

The first two cycles would, therefore, constitute the morpholo-
gical series, and the third, or virulent, cycle would, in modern
language, constitute the biological se?'ies of our parasite.

Morphological Series. — Inferior Cycle. — The inferior cycle
embraces the following phases : —

I. — Phase of Vegetatio?i. — The characters of this phase are
those assigned by Billet to the filamentous state, only that he con-
siders the intertwined state {etat e7ichevetre) as a distinct and later
phase ; whilst we believe that it, in our parasite, accompanies the
filamentous state, in the same manner as the mycelium or creeping
vegetation in fungi. In other words, the intertwined state is even
posterior to the isolated filaments which lead a wandering life in the
liquid substrata, being unable to attain a more vigorous and stable
one ; but it does not constitute a distinct phase, as it is quite natural
that, when the passage to the superior phases is precluded (aerial
vegetation) for want of a fit soil, the filaments intertwine and drop
to the bottom, without being able to spread like the mycelium of
fungi. However, under favourable conditions, a kind of mycelium
(a more complete phase of the entangled state) may be formed,
giving birth to an aerial vegetation, as may be specially observed

432 BACTERIA OF THE SPUTA

in the patina of the tongue and in the deep strata of the patina
dentaria.

II. — Phase of infernal gemmulation or budding and dissemhia-
tion. This partly corresponds to the dissociated state of Billet,
through the disarticulation of the knots of the single filaments, or
through setting free the included bacteria ; and it is clear that the
unstable condition of the nutrient medium continuing, and conse-
quently the passage to the superior phases being prevented^ no
other way of perpetuating the species is left to these micro-organ-
isms than the inferior reproduction or simple multiplication by
shoots and gemmules. Looked at in this way, this phase would
even comprise that held by Billet as endogenous sporulation, but
which are, at least in our parasite, gemmules of reserve, properly
destined to the multiplication of the species, in a neuter state,
through simple fission of the elements, when the genuine repro-
duction, by means of seminules or spores, is not possible, or when
the fertile filaments have been dissevered or cut by mechanical
injuries.

III. — Protective phase. This phase fully corresponds to the
zoogloeic state and to certain conditions of the dissociated state of
Billet, as we have pointed out in the first paragraph. The presence
of such forms has been undoubtedly detected in the mouth, and
even within the relative epithelia. They would appear to be a
kind of reserved fund, preserved in case of any alteration of the
future conditions of pabulum and surroundings, as the author
properly says. We shall speak by-and-by of the relationship of
this phase with the diplococcus of pneumonia.

Here Billet would end the evolutionary cycle, for us, on the
contrary, these first phases would only constitute a cycle, at times
preliminary, at times succedaneous to the second or superior cycle.
The varied elements of the first cycle, being taken separately and
held as special beings or complete living individuals (filaments,
baciUi, bacteria, and cocci), are in reality only particles, trunks,
organs, series of cellules, or cellules endowed mostly with fissipa-
rous multiplication, but destined to constitute a more complex
organism.

Superior Cycle. — This comprises the phases of the properly
called life of reproduction, and these phases are three.

AND CONTENTS OF THE MOUTH. 433

IV. — Agamous Fructification. — Referring to the general laws
of multiplication of the phanerogams by means of bulbs, tubers,
shoots, or buds, and of their genuine reproduction by means of
seeds, it should be borne in mind that with transplantation are
transmitted the accidental modifications brought about by domes-
tication, grafting, etc., which, in the long run, may end in the
degeneration of the plant ; whilst with seeds, on the contrary, the
species reverts to the natural vigour of the wild state.

Now, we incline to believe that something similar may happen
even with cryptogams. Probably in those which have, besides a
fissiparous multiplication, a true reproduction through spores, the
sporulation will mean that the species resumes its native vigour, in
spite of the attacking or enfeebling causes which, as in our para-
site, may impair its vigour.

The seminule or spore may germinate without previous ferti-
lisation, and (as we have already said) we believe this may happen
more frequently in our parasite. In the species studied by Billet,
this external sporification or fructification was wanting, and it is
remarkable that the cocci, which are found abundantly in the
buccal contents, were likewise wanting. It remains to be seen
whether this want of fructification is really the rule, or simply a
consequence of the nature of its pabulum and the material upon
which Billet based his researches. Under other conditions, upon
media not only stable, but favourable to the production of a myce-
lium-like growth, a true and proper fructification might, even in
the above-named species, take place.

In our parasite, the conditions indispensable for the fructifica-
tion are : — «, The solidity and nature of the soil; ^, the protection
against attrition ; and ^, moisture of the saliva.

V. — Organs and Fertilising Eleme7its. — By the side of the
agamous sporulation we have, in many cryptogams, that of conju-
gation. This admits of male organs and fertilising elements or
spermatic threads, of which we have already spoken. In our
parasite, likewise, we have male organs and fertilising elements.
The male organs would first show themselves in the state of young
spermogones or antheridia (or of spermogones or aborted anther-
idia, not developed or reverted to the neuter state), and afterwards
in the state of tufts of ripe pseudo-inflorescences, proceeding from

434 BACTERIA OF THE SPUTA

the first type. On the other hand, the fertilising elements would
be constituted by the spindle-like, comma, or serpentine bacilli,
already formed in the described organs, and finally set free, through
the disarticulation of the tufts already mentioned.

VI. — Conjugated Fructification — i.e.^ that with clavated stem, a
dual zone of colourisation, clusters, or more conspicuous ears,
more bulky and compact spores, destined, perhaps^ to cross unin-
jured the alimentary canal, and to remain alive in the faeces, with-
standing the dissolving action of the gastro-intestinal juices.

Nature, as we see^ has been prodigal to this parasite, by its
various manners of multiplication, adapting each of them to this
or that condition of the nutrient substratum, in order to preserve
and multiply its species, in the midst of numberless and very
varied difficulties. As soon as a higher phase is precluded, or a
nobler element is thrown back, by external injuries, to an inferior
degree, it does not stop from disseminating everywhere particles
apt to germinate and spread extensively the species when it cannot
do it intensively. We are reminded that Nature has even wished
to endow this tiny plant with such a tenacious life, that its elements
on the human teeth cannot be destroyed for centuries, as exhibited
by the tartar on the teeth of Egyptian mummies {vide the preced-
ing Memoir).

If here ends, at least provisionally, the Morphological Series of
our parasite, it only remains to us to say two words on the Biolo-
gical Series in the modern sense, or, rather, on the pathological
phenomena, assigned to some of its forms, or to specific bacteria
similar to the latter.

Biological Series. — Under this title we comprise but three
forms : the Pjieumococcus^ the Bacillus of Koch, and the Gonococcus
of Neisser, already demonstrated, according to our views, in the
two previous Memoirs.

I. — Pneiwiococcus. Few now hold that the pneumococcus is a
specific bacterium, arising externally. It is generally considered
to be either an habitual germ of the mouth (Micrococcus of salivary
septicemia), or, in common with Pommay, a saprophytic bacterium
evolving itself in the sense of virulence. Perhaps it will in time
be known as a simple dissemination of the zooglceic phase of our
parasite, following on the formation of the pulmonitic exudation,

AND CONTENTS OF THE MOUTH. 435

as its greater abundance in the last stages of pneumonia, its
presence in traumatic pneumonia, and other evidences will
prove it to be so. But even admitting that the evolution in the
sense of virulence may take place in the mouth and not in the
respiratory organs affected (as regards virulence, which may be
inoculated) ; admitting that it has preceded and not followed
pneumonia, we cannot necessarily infer that the disease proceeded
from this coccus. But even the colonies of these diplococci, when
repeatedly transplanted in other culture media, or even the media
themselves, may become contaminating through inoculation, this
circumstance may also occur with other salivary bacteria (for
example, Bacillus crassus sputtgenus), and might be interesting in
experimental pathology ; but, botanically speaking, it does not
implicitly imply a separate specific entity. We repeat that we do
not impugn, but rather try to conciliate the results of the inocula-
tions with those of the morphological research.

II. — Bacillus of Koch. Our remarks concerning this bacillus
are very similar, and we hope at a future time to devote a special
Memoir to it. The reasons which induced us to believe the
bacillus in rosaries to be a dissemination of the small spores of
Leptothrix spread over the tubercular spots, and the rod-shaped
bacilli as proceeding from other elements of Leptothrix^ have been
already given in the preceding Memoirs. Their greater dissemi-
nation in phthisis than under other conditions may depend upon
different causes, and partly, perhaps, from the following simple
reason : — Breathing through the nose, as we generally do, only a
few germs of a purely buccal origin are inhaled ; but the position
becomes altered when we breathe through the mouth as well, as
happens in phthisis, because of panting or burning heat : —

" . . open'd wide his lips,
Gasping as in the hectic man for drought.
One towards the chin, the other upward curl'd."

— Dante, Inferno^ xxx., Gary's Transl.

Now, the small sporules of Leptothrix exclusively originate
from the patina dentaria, and without that particular form of
breathing (/.^., by the mouth) they cannot gather in any great
number into the air-passages. Many also, in sleeping, breathe

436 BACTERIA OF THE SPUTA

likewise with their mouth ; but in the normal conditions, however,
the ciliary action continuing unhurt through the air-passages, the
inhaled leptothrical elements cannot reach the pulmonary tissue,
but are instead thrown out and expectorated with the sputa, as
stated in the other Memoir.

III. — Go?iococcus of Neisser. Probably, says Pommay, a normal
bacterium of the urethra is the progenitor of the gonococcus of
Neisser ; it is useless to repeat here that relationship. Let it
suffice to record the fact that we have detected in the urine num-
berless gonococci, in a case of carcinoma of the bladder, inde-
pendently from any gonorrheal contagium whatever.* According
to the morphological characteristics, the gonococci in question do
not differ from the ordinary arched diplococci, and therefore can
be held, till proved otherwise, to be derivations from the state of
sarcina (one form of the zoogloeic state). As regards the manner
by which the leptothrical elements penetrate from the external
genitals into the urinary passages, as well as the presence of analo-
gous forms (curved diplococci) in the contents of the mouth, in
sputa or the middle ear ; and also as regards the discovery in the
urine or sperm of capsulated forms (forms analogous to pneumo-
cocci), we refer to the previous Memoirs.

From the morphological sketch we have just given, nothing
perfectly absolute and incontroverted is to be inferred, either for
or against any previously acknowledged systematic view ; but
perhaps few people will doubt that, in the field of modern bacte-
riology, much still remains to be done, and a great deal of discus-
sion, combined with careful study, will be required before any
definite and satisfactory results will be arrived at concerning the
pathogenesis of infectious diseases (we are, of course, now alluding
to those cases which are strictly clinical). Many will, we are sure,
agree with us that, with regard to bacteria, our knowledge is so
limited that no method of investigation will appear superfluous in
order to study aright their genesis and properties in order tho-
roughly to understand and appreciate their function in our
economy.

F. ViCENTiNi, Corresponding Member.
Chieti; May, i8q2.

*Atti della R. Accademia Msdico-Chirurgica di Napoli, tomo XLIII., 1890.

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AND CONTENTS OF THE MOUTH. 437

EXPLANATION OF PLATE XX.

Figures taken from Billet :

Fig. 17. — Articulations analogous to the pneumococci, belonging to
various bacteriological species on the point of passing to the
dissociated or to the zoogloeic state, a, A fragment of six
articulations of Cladothrix dichotoma in disintegration, x 320.

b, Articulations of the same alga in more advanced disinte-
gration, X 1600. c, d, Bacterium osteophiUim, ready to pass
to the zooglo3ic state, x 600. e, A fragment of four articu-
lations of Bacterium osteophilum on the point of passing to
the scorpioidal state, x 600. Small zoogloeic group of
Leptothrix parasitica, Kxiizmg^ x 745.

18. — Other analogous articulations. a. Rectilineal forms of
Cladothrix dichotoma in the act of passing to the zooglojic
state (stained first with solution of iodine, then with methyl
violet or fuchsine), x 600. 6, Beginning of the zoogloeic
state of the Bacterium osteophilum (colouring with vesuvine,
then with methyl-violet, and lastly with solution of iodine),

X 600. c. Beginning of its scorpioidal state (same colour-
ing), X 600. f/, Same as 6, enlarged, x 1600. e, Zoogloeic
group of Leptothrix parasitica^ Kiitzing (colouring as in a),

X 320.

19. — Ramified zoogloea of Cladothrix dichotoma, formed by 21
branches, upon a single peduncle (same colouring as Fig.
2, a), X 120.

20. — Superior endings, more enlarged, of two of the preceding
branches (same colouring). «, &, Tops of branches, x 600.

c, A portion of one of them, more enlarged, containing
bacteria and bacilli of diflferent shape and form, x 1050.

21. — Leptothrix parasitica, Kiitzing, vegetating on two crossed
stems : the one of zyynema, the other of Cladothrix (colour-
ing with vesuvine and methyl-violet, then with solution of
iodine), x 600. a, a, Stem of Zygnema. b, b, Stem of
Cladothrix. c, c, c. Filaments oY Leptothrix pjarasitica.
s, s, Their bulbs or engrafting spores.

22. — A part of the previous figure, more enlarged (same colour-
ing), X 1600. c, c, c. Filaments of Leptothrix pjarasitica.
s, s, Their bulbs or engrafting spores.

Original Figures :

23.— Ears or clusters of Leptothrix racemosa, with acidulated
solution of iodine, a, Young cluster, with small, thin spores
upon their sterigms, x 1700. b, b, Groups of bacteria and
comma bacilli, c, A matured cluster, with sterigms and
thicker spores, x 1170. d, Fragment of ear, with sterigms
without spores, excepting two spores, still adhering, x 1170.

24.— Cluster showing the peduncles or sterigms, funnel-shaped,
and the central stem, containing minute gemmules of
reserve, stained with weak gentian violet, x 3100.

>»

3»

438 MOLLUSCS AND BRACHIOPODS.

Fig. 25. — Ear, foreshortened, seen upon a turned-up stem, with a ter-
minal rosette of six sterigms and relative spores on the top,
stained with acidulated solution of iodine, x 1700.

26. — Clavated stems, stained with gentian violet, x 1700. a,
Stem with a perfect clava, but not yet fructified, h, Stem
with a short clava, in formation.

27. — Ear with two colouring zones, with clavated stem (fructified)
and more compact spores (teleutospores ?), stained with
gentian violet, x 1700.

28. — Sheath expansion (young antheridium or spermagonium ?),
containing slunder transversal fine beams (future fecundating
elements ?), stained with strong gentian violet, x 3100.

, , 29. — Ear doubled up at the top, stained with acidulated solution
of iodine, x 1700. a, Long stem, h, Point of the ear,
doubled up obliquely and pressed down on the middle third,
c, Elbow simulating a gibbosity.

30. — Ear, apparently pyriform, through superposition of adventi-
tious cocci and bacteria, stained with gentian violet, x 1170.
a. Cap, at first stage of colourising, pale, formed by adven-
titious cocci and bacteria (through contact of lips ?) up to
the middle, d, d, of the internal ear. 6, b, Internal ear,
brilliantly coloured, c, Stem.

) J

))

)>

»j

flDonu0C6 anb Bracbiopoba.

*

IT is with much pleasure that we are, through the kind courtesy
of Messrs. Macmillan and Co., enabled to direct the atten-
tion of our readers to the first published volume of The
Cambridge Natural History.

The series, which is edited, and for the most part written, by
Cambridge men, is to consist of ten volumes, each of which will
contain about 500 pages and will be complete in itself The
volumes have been numbered on a definite plan, but will be pub-
lished in the order in which they are ready for the press. The
one before us is Vol. III. of the series.

T/ie Cambridge Natural History is intended, in the first

* Molluscs. By the Rev. A. H. Cooke, M.A., Fellow and Tutor of

King's College, Cambridge. Brachiopods (Recent). By A. E, Shirley,

M.A., Fellow of Christ's College, Cambridge. Brachiopods (Fossil).

By F. R. C. Reed, M. A., Trinity College, Cambrid4e. Royal 8vo, pp. xiii. —
535. (London: Macmillan and Co. 1895.) Price 17/- net.

MOLLUSCS AND BRACHIOPODS.

439

instance, for those who have not had any special training, and
who are not necessarily acquainted with scientific language. At
the same time, an attempt is made, not only to combine popular
treatment with the latest results of scientific research, but to make
the volumes useful to those who may be regarded as serious
students in the various subjects.

The general plan of classification adopted in the work before
us is not that of any single authority. It has been thought better
to adopt the views of recognised leading specialists in the various
groups, and thus place before the reader the combined results of
recent investigation.

Fig. I, — Eye of Helix pomatia, L.,
retracted within the tentacle ; c. , cornea ;
ej>. , epithelial layer ; /. , lens ; op. n. ,
optic nerve ; r. , retina. (After Simroth).

'^cpji

The volume opens with a Scheme of the Classification of the
Mollusca adopted in this book ; followed by chapters on the Posi-
tion of Mollusca in the Animal Kingdom ; Origin of Land and
Fresh-water Mollusca ; Their Habits and General Economy ;
Their Enemies ; Means of Defence, etc. etc.

As the publishers have very kindly placed some of the illustra-
tions at our disposal, we will now pass on to Chapter VII., which
treats of the Organs of Sense: Touch, Sight, Smell, Hearing;
The Foot and the Nervous System, and quote briefly —

The Organisation of the Molluscan Eye (p. i8i). — The eye in
Mollusca exhibits almost every imaginable form, from the extremely
simple to the elaborately complex. It may be, as in certain
bivalves, no more than a pigmented spot on the mantle, or it may

440

MOLLUSCS AND BRACHIOPODS.

consist, as in some of the Cephalopoda, of a cornea, a sclerotic, a
choroid, an iris, a lens, an aqueous and vitreous humour, a retina,
and an optic nerve, or of some of these parts only.

In most land and fresh-water Mollusca the eye may be re-
garded, roughly speaking, as a ball connected by an exceedingly
fine thread (the optic nerve) with a nerve-centre (the cerebral
ganglion) In Helix (Fig. i) there is a structureless

op.n

2. — Eyes of Gasteropoda, showing arrest of development of successive
A, Patella; B, Trochus ; C. Turbo; D, Murex ; ep., epidermis;

Fig.
stages :
/., lens ; oj). n., optic nerve ; r., retina; v.h., vitreous humour (after Hilger).

membrane, surrounding the whole eye, a lens, and a retina, the
latter consisting of a nervous layer, a cellular layer, and a layer of
rods containing pigment, this innermost layer (that nearest the
lens) being of the thickness of half the whole retina.

Comparing together the eyes of different Gasteropoda, we find
that they represent stages in a general course of development.

MOLLUSCS AND BRACHIOPODS. 441

Thus, in Patella the eye is scarcely more than an invagination or
depression in the integument, which is lined with pigment and
retinal cells. The next upward stage occurs in Trochus^ where
the depression becomes deeper and bladder-shaped^ and is filled
with a gelatinous or crystalline mass, but still is open at the top,
and therefore permits the eye to be bathed in water. Then, as in
Turbo, the bladder becomes closed by a thin epithelial layer,
which finally, as in some Murex, become much thicker ; while the
' eye-ball ' encloses a lens (Fig. 2), which probably corresponds
with the ' vitreous humour ' of other types.

In Chapter VIII, is described The Digestive Organs, Jaw, and
Radula, and Excretory Organs. As the mouth-organs are always
specially interesting to microscopists, we make a few short extracts.

The mouth is generally, as in the common snail and periwinkle,
placed on the lower part of the head, and may be either a mere
aperture, circular or semi-circular, in the head-mass, or, as is more
usual, may be carried on a blunt snout, which is capable of varying
degrees of protrusion. From the retractile snout has doubtless
been derived the long proboscis, which is so prominent a feature
of many genera. ... As a rule, Mollusca provided with a
proboscis are carnivorous, while those whose mouth is on the
surface of the head are vegetable feeders ; but this rule is by no
means invariable.

The Pharynx, J^i^s, and Radula. — Immediately behind the
lips the mouth opens into a muscular throat, pharynx, or buccal
mass. The pharynx of the Glossophora — i.e., of the Gasteropoda,
Scaphopoda, and Cephalopoda — is distinguished from that of the
Pelecypoda by the possession of two very characteristic organs for
the rasping or trituration of food before it reaches the oesophagus
or stomach. There are {a) the Jaw or jaivs, and (b) the radula/"'
odontophore, or lingual ribbon. The jaws bite the food, the radula
tears it up small before it passes into the stomach to undergo
digestion. The jaws are not set with teeth like our own ; roughly
speaking, the best idea of the relations of the molluscan jaw and
radula may be obtained by imagining our own teeth removed from
our jaws and set in parallel rows along a greatly prolonged tongue.

* Radere, to scrape ; hlo^g, tooth ; tpipuv, to carry.

International Journal of Microscopy and Natural Science.
Third Series. Vol. V. ff

442

MOLLUSCS \ND BRACHIOPODS.

The radula itself is a band or ribbon of varying length and
breadth, formed of chitin, generally almost transparent, some-
times beautifully coloured, especially at the front end, with red or
yellow. It lies enveloped in a kind of membrane, in the floor of
the mouth or throat, being quite flat in the forward part, but
usually curving up so as to line the sides of the throat farther back,
and in some cases eventually forming almost a tube. The upper

Fig. 3. — Portion of the radula of Melongena verpertilio, Lam., Ceylon, x 30.

surface — i.e.^ the surface over which the food passes — is covered
with teeth of the most varied shape, size, number, and disposition,
which are almost invariably arranged in symmetrical rows. These
teeth are attached to the cartilage, on which they work by muscles,
which serve to erect or depress them ; probably also the radula,

Fig, 4. — Portion of the radula of Ebiirna japonic a ^ Sovvb., China, x 30.

as a whole can be given a forward or backward motion, so as to
rasp or card the substances which pass over it.

The extreme importance of a study of the radula depends
upon the fact that in each species, and, a fortiori^ in each genus

MOLLUSCS AND BRACHIOPODS.

443

and family, the radula is characteristic ; thus, in Melongena vesper-
tilio (Fig. 3), the central tooth is tricuspid, the central cusp being
the smallest, while the laterals are bicuspid ; in Ebtirna Japofika
(Fig. 4) the central tooth is 5-cusped, the two outer cusps being
much the smallest. The teeth, on the whole, are sharp and hooked,
with a broad base and formidable cutting edge.

Fig. 5. — View of the left half of
Cistella ( Argiope) neapolitana, which
has been cut in two by a median longi-
tudinal incision to show the disposition
of the organs. Partly diagrammatic.
The inorganic part of the shell only is
shown. The tubular extensions of the
mantle and the organic outer layer are
not included, and hence the pores
appear open.

I. — The ventral valve.

2. — The dorsal valve.

3. — The stalk.

4. — The mouth.

5. — Lip, wMch overhangs the mouth
and runs all round the tentacular arms.

6. — Tentacles.

7. — Ovary in dorsal valve.

8. — Liver diverticula.

9. — Occlusor muscle ; its double or-
igin is shown.

10. — Internal opening of left neph-
ridium.

II. — External opening of left neph-
ridium.

12. — Ventral adjustor. The line from
10 crosses the dorsal adjustor.

13. — Divaricator muscle.

We will now turn to Chapter XVII., which treats of Recent
Brachiopoda. The body of a Brachiopod is enclosed within a
bivalve shell, but the two halves are not, as they are in the Pele-
cypoda, one on each side of the body, but occupy a different posi-
tion with regard to the main axis of the body (Fig. 5).

The shell of a Brachiopod is secreted partly by the general

444 MOLLUSCS AND BRACHIOPODS.

surface of the body, which is situated at the hinder end of the
shell and partly by the two leaf-like extensions of the body, which
are termed the dorsal and ventral mantles. These are, in fact,
folds in the body-wall, and into them the body cavity and certain
of its contents, such as the liver and generative glands, etc., extend.

Microscopic examination of thin sections of the shell shows
that it consists of small prisms or spicules of calcareous substance,
whose long axis lies, roughly speaking, at right angles to the
surface of the shell. These spicules are held together by an
organic matrix, in which, however, no cellular elements can be
detected. In sections made through a decalcified shell the posi-
tion of the spicules which have been dissolved by the acid is
indicated by spaces, and the matrix remains as a network of
fibrils, which end on the outside in a thin cuticular layer of
organic matter.

We trust we have said sufficient to interest our readers in these
very interesting classes, and to show how thoroughly the subject
has been treated by the authors. Our best thanks are due to
publishers for the use of the electros, and for permission to make
the above extracts.

Solders for Glass. — Mr. Chas. Margot finds that an alloy
composed of 95 parts of tin and 5 of zinc melts at 200 degrees,
and becomes firmly adherent to glass, and moreover is unalterable
and possesses a beautiful metallic lustre ; and, further, that an
alloy composed of 90 parts of tin and 10 of aluminium melts at
390 degrees, becomes strongly soldered to glass, and is possessed
of a very stable brilliancy. With these two alloys it is possible to
solder glass as easily as it is to solder two pieces of metal. It is
possible to operate in two different manners. The two pieces of
glass to be soldered can either be heated in a furnace and their
surfaces be rubbed with a rod of the solder, when the alloy as it
flows can be evenly distributed with a tampon of paper or a strip
of aluminium, or an ordinary soldering iron can be used for melt-
ing the solder. In either case, it only remains to unite the two
pieces of glass and press them strongly against each other, and
allow them to cool slowly. — Set. American.

[ 445 ]

1Revicv\)6.

Open-Air Studies: An Introduction to Geology Out-of-doors.
By Grenville A. J. Cole, M.R.I. A., F.G.S., etc. Crown 8vo, pp. xii. — 322.
(London : Chas. Griffin & Co. 1895.) Price 8/6.

The aim of the author of this interesting book has been to keep in view
the fact that Geology, like true zoology and true botany, is a study for the open
air. The twelve chapters into which the book is divided treat of The Material
of the Earth ; A Mountain Hollow ; Down the Valley ; Along the Shore ;
Across the Plain ; Dead Volcanoes ; A Granite Highland ; The Annals of the
Earth ; The Surrey Hills ; The Folds of the Mountains. There are 1 1 plates
and 33 illustrations in the text.

Studies in the Evolution of Animals. By E. Bonavia,
M D. Cr. 4to, pp. xxxiv. — 362. (Westminster : Archibald Constable & Co.
1895.) Price 21/- net.

In the preface to this handsomely got-up book the author tells us that,
" Thinking over the rosettes of the Leopards, and more especially those of the
Jaguar, and seeing spotted Horses constantly in ihe streets of London, some
new ideas flashed across my mind regarding the origin of all this spotting and
rosetting in mammals." The subjects of the curious callosities on the legs of
the Horse, its solitary leg digit, its possible close relationship to the pair of
digits in the ruminants, and various monstrosities, also came under his notice ;
and he was led to the conclusion that they must have a deeper meaning than may
have hitherto been attributed to them by evolutionists. We feel sure our read-
ers will be deeply interested in a careful perusal of this work. There are 128
illustrations.

A Laboratory Guide for the Dissection of the Cat: An

Introduction to the Study of Anatomy. By Fredric P. Gorham, A.M., and
Ralph W. Tower, A.M. 8vo, pp. ix. — 87. (New York : Charles Scribner's
Sons. 1895.)

This book will prove a valuable laboratory guide for elementary classes in
anatomy. The instructions are very concisely given. There are 7 capital plates
showing Skeleton ; Superficial Muscles of Right sight ; Deeper Muscles on
Right side ; Superficial and Deeper Muscles of Ventral side ; Arterial System ;
Venous System ; and Nervous System.

Year Book of the Scientific and Learned Societies of

Great Britain and Ireland. 8vo, pp. v. — 254. (London : Charles Griffin &
Co. 1895.) Pj^ice 7/6.

The 1 2th annual issue of this exceedingly useful work is before us. It
gives us a chronicle of the work done during the year 1894 by all the various
societies, together with information as to official changes. By referring to this
list we find full particulars of the various societies, date of formation, name of
the President, name and address of the Secretary, date and time of the Meet-
ings, and list of Papers read ; also where these Papers are published. We
find the Year-Book a valuable work for reference.

Science Readers. By Vincent T. Murche. Book IV. Cr.
8vo, pp. 216. (London: Macmillan & Co. 1895.)

This book foUows'the three noticed in our last issue ; the whole forming a
valuable and very instructive series of school reading books. The illustrations
are very effective.

446 REVIEWS.

Curious and Instructive Stories about Wild Animals and
Birds. Cr. 8vo, pp. xii. — 340. (Edinburgh: W. P. Nimmo& Co.) Price 2/6.

We have here nine instructive and amusing stories, with some good illus-
trations.

A Chapter on Birds, Rare British Visitors. By R. Bowdler
Sharpe, LL. D., F. L.vS. , etc. Cr. 8vo, pp. x. — 124. (London : Society for
Promoting Christian Knowledge. 1895.) Price 3/6.

Mr. Bowdler vSharpe, of the Zoological Department. British Museum, gives
here very nice descriptions of eighteen of our very beautiful visitors, each des-
cription being accompanied by a fine coloured plate of the bird, drawn to scale,
and the egg, natural size.

An Introduction to the Study of Zoology. By B. Lind-
say, C.S., of Girton College, Cambridge. Cr. 8vo, pp. xix. — 356. (London:
Swan Sonnenschien & Co. 1895.) Price 6/-.

The aim of the author of the volume before us has been to supply a simple
outline sketch of the animal kingdom. Part L treats of General Principles of
Zoology ; Part IL of Systematic Zoology ; and Part III., Advice to Students
on the Use of Books and on Practical Work. ' Animals as Fellow Creatures '
is the title of the 3rd chapter of this part. There are 124 illustrations, and a
glossary. The volume goes very thoroughly into the subject of which it treats,
and the general student will doubtless gain much information from a careful
study of it.

Consider the Heavens : A popular introduction to Astron-
omy. By Mrs. William Steadman Aldis. Cr. 8vo, pp. 224. (London : The
Religious Tract Society. 1895.) Price 2/6.

This book has been written for those who are at present quite ignorant of
astronomy, and especially for such as have not much time for study. The book
is written in a thoroughly interesting manner and is nicely illustrated.

Hidden Beauties of Nature. By Eichard Kerr, F.G.S.

Foolscap 4to, pp. 256. (London : The Religious Tract Society. 1895.) 3/6-
The chapters in this book contain, in simple language, the main points of
lectures delivered to scientific societies, colleges and upper-class schools, and to
large audiences in various parts of England. A few of the subjects are : On
the Study of Nature ; How to Begin ; The Sea-Urchin ; Nature's Fireworks ;
The Euplectella; Atlantic Ooze; Diatoms; Eggs of Insects; &c. &c. There
are 59 beautiful illustrations.

Light from Plant Life : Truths derived from and illustrated
by the Life History of Plants. By H. Girling. Cr. 8vo, pp. xiv. — 178.
(London: T. Fisher Unwin. 1895.) Price 3/6.

This work is chiefly designed for those who desire to exercise their powers
of thought, and sets forth the spiritual life as illustrated every day by plants
and trees.

Angling and How to Angle : A practical guide to Bait-
fishing, Trolling, Spinning, and Fly-fishing. By J. T. Burgess. Revised and
brought down to date by R. B. Marston ; with a special article on Pike-fishing
by A. J. Jardine. Cr. 8vo, pp. x. — 212. (London: F. Warne and Co. 1895.)
Price i/-

A comprehensive, practical, and handy manual, which is neither too large
for the pocket, nor too brief to be useful. Besides some 70 illustrations of
tackle, flies, etc., it contains a number of practical hints on the making and
mending of fishing gear, fly-dressing, and other memoranda which will be duly
appreciated.

REVIEWS. 447

The Plants of the Bible. By the Rev. George Henslow,
M.A., F.L.S., &c. Foolscap 8vo, pp. 128. (London: The Religious Tract
Socety. ) Price i/-

One of an interesting series of books published by the Society and known
as "Present Day Primers." It gives some of the most interesting features
rekting to the 120 plants mentioned in the Bible; there are several illustrations.

The Story of the Plants. By Grant Allen. i2mo, pp.
232. (London: George Nevvnes. 1895.) Price r/-

This is a most interesting and instructive Httle book, in which the author
yives a short and succinct account of the principal phenomena in plant life, in
language suited to the comprehension of unscientific readers.

Die Naturlichen Pflanzenfamilien. By A. Engler. Parts
120, 121, 122. (London: Williams & Norgate. Leipzig: Wilhelm Engelmann. )

These parts contain the completion of the Loganiacece, by fl. Solereder ;
Gentianaceee, by E. Gilg ; Apocynacece . by K. Schumann, and the commence-
ment of the Asclepiadacese, by the same author. There are 34 illustrations,
consisting of 411 figures. The price of these numbers is 3 marks, or by sub-
scription, I '50 m. each.

The Art of Massage : Its Physiological Effects and Thera-
peutic Applications. By J. H. Kellogg, M-D. 8vo, pp. xvi. — 282. (Battle
Creek, Mich., U.S.A. : Modern Medicine Pub. Co. 1895.) Price $3 = 12/6

The work before us goes thorougly into the subject on which it treats and
is profusely illustrated with a great number of well-executed photo-mechanical
plates. The author directs special attention to the classification of the different
procedifres of massage, and by a careful study of those described by the best
authorities, and employed by expert manipulators, it was found possible to
include all in seven different general classes with sub-divisions, each of which
has been described with a very considerable degree of painstaking care. In
this work there are 45 excellent plates, each showing on an average 4 distinct
figures.

Cholera : Its Protean Aspects and its Management. By
Dr. G. Archie Stockwell, F.Z.S.

Whooping Cough. Vols. I. and II. By Dr. H. Richardiere,
Paris. Translated by Joseph Heleman.

Antiseptic Therapeutics Vols. I. and II. By Dr. E. L.

Troussardt, Paris. Translated by E. P. Hurd, M.D.

Modern Climatic Treatment of Invalids with Pulmonary

Consumption in Southern California. By P. C. Romondino, M.D.

Cerebral Meningitis : Its History, Diagnosis, Prognosis,
and Treatment. By Martin W. Barr, M.D.

Intestinal Diseases of Infancy and Childhood : Physiology,
Hygiene, Pathology, and Therapeutics. By A. Jacobs, M.D.

A Treatise on Diphtheria. By Dr. H. Bourges. Trins-
lated by E. P. Hurd, M.D.

Pernicious Fever : A clinical study of the Fevers of Rio de
Janeiro. By Dr. Joas Vincente Torres Homem. Translated by Surgeon
George P. Bradley, U.S. Navy.

All the above are volumes of the Physician's Leisure Library. They
contain short practical treatises, prepared by well-known authors, and give

448 REVIEWS.

the gist of what they have to say regarding the treatment of diseases commaily
met with and of which they have made a special stud)'. Many of the vohmes
are ilkistrated, and are published by George S. Davis, Detroit, Mich., U.S.A.
Price 25c. each, in paper covers, or 50c. , bound in cloth.

Microbes and Disease Demons. The Truth about ihe

Anti-Toxin treatment of Diphtheria. By Edward Burdoe, L.R.C.P. Ec. ,
M.R.C.S. Eng., etc. Cr. 8vo, pp. 93. (London: Swan Sonnenschein a:id
Co. 1895.) Price i/-

The author commences by saying "The most ancient and wide-spread
theory of disease is the demon theory." On page 12 he says : '" The disease
demon has now reappeared as a germ. Some 36 diseases, many of which are
the most terrible, which afflict men and animals are attributed by bacteriologists
to micro-organisms." And goes on to say : " I cannot think it can ever be true
scientific medicine to pour poison into the blood current to counteract other
poison ; we may in one sense convey an antidote, but we may work untold mis-
chief by our ignorant meddling, which we have no means of combating."

Dreamy Mental States. By Sir James Crichton-Browne,
M.D., LL.D., F.R.S. , etc. Svo, pp.32. (London: Bailliere, Tindall, &
Cox. 1895.) Price i/-.

This is the Cavendish Lecture delivered before the West London Medico-
Chirurgical Society, on Thursday, June 20th, 1895.

Herbal Simples approved for Modern Use or Cure. By W.
T. Fernie, M.D. Cr. 8vo, pp. xvi. — 432. (Bristol : John Wright & Co.
London : Simpkin, Marshall, & Co. ; and Herschfield Bros. 1895.) Price 5/-

" Various British Herbalists," the author tells us, "have produced works,
more or less learned and voluminous, about our native plants ; but no author
has hitherto radically explained the why and the wherefore of their ultimate
curative action. . . . Chemically assured of the sterling curative powers
which our Herbal Simples possess, and anxious to expound them with a com-
petent pen, the present author approaches the task with a zealous purpose."
Some 300 plants are named and their properties described.

Eyesight and School Life. By Simeon Snell, F.R.C.S.
Ed., etc. 8vo, pp. xii. — 70. (Bristol : John Wright & Co. London : Simp-
kin, Marshall, & Co. ; and Herschfield Bros. 1895.) Price 2/6.

A large amount of valuable information is here given. The author states
that there is abundant and convincing evidence that the vision of children,
which should under normal conditions have remained good, is constantly deteri-
orating during the school period. He points out many of the causes of this
deterioration, and suggests remedies. There are 15 illustrations.

A New English Dictionary on Historical Principles. Ed.
by Dr. James A. H. Murray. Deject — Depravation. (Oxford : The Claren-
don Press. London : Henry Frowde. July, 1895.) Price 2/6.

This section (a portion of Vol. HL), which covers the words from Deject
to Depravation, contains 1269 main words, 37 combinations explained under
these, and 138 subordinate words ; to which may be added 125 obvious combi-
nations recorded and illustrated without definition, bringing up the total to
1569 ; and of these 1365 are illustrated by quotations.

REVIEWS. 449

Arithmetic Prize Papers. By W. P. Workman. Foolscap

8vo, pp. 60. (London: Joseph Hughes & Co. 1895.) Price 2/-

For many years past a silver medal has been awarded annually at Kings-
wood School (of which the author is Head Master) 'to the best Arithmetician.'
The endowment for this purpose was left to the School at a time when Arith-
metic was the only equipment of an educated gentleman. The author has
no doubt the donor meant 'the best Mathematician,' but he did not say so, and
consequently a few of the most difficult questions capable of being answered
by Arithmetic have been prepared. Four papers, each containing 12 to 15
questions, cover 8 pages of the book, the remaining 48 being required for their
working out. We think it would take a very clever boy to answer most of
them.

An Elementary Text-Book of Mechanics. By William
Briggs, L.L.B., F.R.A.S., etc., and G. H. Bryan, M.A., F.R.S., etc. Cr.
8vo, pp. vii. — 336. (London : W. B. Clive. 1895.) Price 3/6.

This is one of " The University Tutorial Series," in preparing which the
aim of the authors has been to afford beginners a through grounding in those
parts of Dynamics and Statics, which can be treated without assuming a pre-
vious knowledge of Trigonometry. The section devoted to Dynamics is divi-
ded into three parts: — I., Velocity and Acceleration; II., Mass and Force ;
and HI., The Parallelogram Law. And Statics : — I., Equilibrium of Forces
at one point; II., Moments and Parallel Forces; and HI., Centres of Gravity.
The answers are at the end of the book.

Elementary Trigonometry. By Charles Pendlebury, M.A.,
F.R.A.S., etc. Cr. 8vo, pp. xvi. — 336. (London : George Bell & Son.
1895.) Price 4/6.

The examples in this book are numerous and varied, and have been care-
fully graduated ; and at suitable places sets of oral examples have been inser-
ted, similar to those in the "Arithmetic for Schools," by the same author ; and
towards the end of the work there will be found a set of questions on book-
work, based upon the text. Answers are at the end of the book.

Mathematical Questions and Solutions. Edited by W. J.
C. Miller, B.A. Vol. LXiii. 8vo, pp. 128. (London: F. Hodgson. 1895.)

This volume consists of Mathematical Questions with their Solutions, taken
from the Educational Tvnes^ with many others which were not published in
that Journal. There will be found in it contributions in all branches of Mathe-
matics from many of the leading Mathematicians at home and abroad.

Matriculation Directory. June, 1895. Cr. 8vo, pp. 64

-I- 132. (London Ofhce : 32 Red Lion Square, Holborn. )

This volume of " The University Tutorial Series " contains articles on the
special subjects for January and June, 1896, with the Calendar for 1894 — 5.
Those students who contemplate going in for their ' Matric.,' will do well to
study this book. The Calendar for 1894 — 5 occupies the first part of the book.
The subjects treated in the Directory proper are : I. — Matriculation Regu-
lations ; II. — Text Books; HI. — Special Subjects for January and June, 1896 ;
IV. and V. , which we advise all would-be candidates to study, give the papers
set on the various subjects in June, 1895, with their solutions.

Stenopaic or Pin-Hole Photography. By F. W. Mills,
P\R.M.S., and A. C. Ponton. 8vo, pp. 27. (London : Dawbarn and Ward.
1895.) Price i/-.

450 REVIEWS.

«
Good results may be obtained from pin-hole photography, as will be seen
from the frontispiece of this little work. The authors state that a hole i/iooth
of an inch in diameter, accurately drilled in a very thin plate, can "be used with
perfect success for ordinary out-of-door work, from i-in. focus up to 5-in. focus,
over almost any angle, and in studio work for enlarging the same sized hole
can be advantageously used from 5-in. focus up to 30-in. focus.

Texte et Tables de la Collection des Diatomees Du Monde

Entier. ByJ. Tempereand H. Peragallo. 8vo, pp. 304 + 62. Price 18 francs.
Mons. Tempere appears to have given special attention to the various
diatomaceous deposits, the first portion of this work being taken up with an
enumeration of gentra and species found in each deposit. On the last 50 pages
is given a classihed alphabetical list of genera and species, and w^here found.
The diatomist will find this a valuable w^ork of reference. We are sorry to
notice there are no illustrations ^

Science Progress : A Monthly Review of Current Scientific
Investigation. (London : The Scientific Press.) Price 2/6 monthly. Sub-
scription price, 25/- per annum post free.

The third volume of Science Progress, conducted by Henry C. Burdett,
edited by J. Bretland Farmer, M.A. , was completed with the August part.
The volume contains articles by well-known scientists on the following
subjects: — Pathology: Antitoxin; Mountain Sickness; The Antitoxins of
Diphtheria ; and Pathological Results of the Royal Commission on Tubercu-
losis. Geology, Mineralogy, and Palceontology : Foreign Work among the
Older Rocks ; Recent Contributions to the Geology of the Western Alps ;
Methods of Petrographical Research ; Pithecanthropus Erectus ; Geology of
the Sahara ; A Type of Palaeolithic Plants ; and Views on Mineral Species.
Botany : Insular Floras (Parts 4 & 5) ; Reserve Material of Plants ; Metam-
orphism in Plants ; What is a Tendency ? ; Notes on the Reproductive Organs
of Olive-brown Seaweeds ; and New Aspects of an old Agricultural Question.
Physiology: Peptone; Coagulation of Blood ; Two Fundamental "Laws" of
Nerve Action in relation to the Modern Nerve-Cell; and Fonnation of Lymph.
Animal Alorphology : Budding in Tunicata. Anthropology : Spanish Anthro-
pology. Chemistry and Physics : The Arrangement of Atoms in a Crystal ;
Light and Electrification ; Progress in Physical Chemistry during 1894 ; Ratio
of the Specific Heats of Gases ; Recent Values of the Magnetic Elements at
the Principal Magnetic Observatories of the World ; Chemical Affinity ; and
Space Relation of Atoms. Cytology : On the Protoplastid Body and the
Metaplastid Cell ; Notices of Books and Titles of Chemical Papers.

The Buried Cities of Vesuvius: Herculaneum and Pompeii.
By John Fletcher, M.D., D.Sc, &c. 8vo, pp. viii. — 115. (London: Hazell,
Watson, and Viney. 1895.) Price 3/6.

In this interesting work, illustrated with six plates, the author gives an
account of Vesuvius and its Eruptions ; Rediscovery of Pompeii and Hercula-
neum ; Handicraft, Literature, and Art ; Social Life of the Pompeians ; Mar-
riage, Divorce, Death, and Burial, etc. The book is nicely got up and photo-
process plates good.

Friends in Fable : A Book of Animal Stories. By various
Authors.

Stories in a Shell. By various Authors. Cr. 4to, pp. 80
and 64. (London: Raphael Tuck and Sons. 1S95.) Prices 3/6 and 2/6.

Two handsome and beautifully illustrated books for young people ; the
stories are sure to delight the little folks, and the coloured plates are, we think,
the best of the kind we have seen.

REVIEWS. 451

Notable Answers to One Thousand Questions. Cr. 8vo,

pp. xvi. — 463. (London: George Newnes. 1895.) Pi'ice 2/6.

These are a reprint of the Sixth Thousand Questions in the Inquiry
Cohmins of Tit-Bits^ with the Replies. These questions appear to embrace
ahiiost every conceivable subject, and their answers afford a large amount of
valuable information.

The Chess Openings. By J. Gunsberg. Post 8vo, pp. xv.

— 104. (London: Geo. Bell and Son. 1895.) Price I /-

Those who are not proficient at this roost interesting game will derive much
valuable information from the study of Gunsberg's openings. Here he will
gain an idea of the best methods of opening a game, besides learning the methods
and tactics of the best players.

Chess Problems. By Philip H. Williams. i6mo, pp. viii. —

58. (New Barnet : W. W. Morgan. London : Simpkin, Marshall, & Co.
1895.) Price i/- '

This little book contains 56 and two special problems, making 58 in all.
Many have appeared in various newspapers, but all have been composed within
the last four years.

The Book of the Fair. Parts XL and XIL (Chicago :
The Bancroft Publishing Co.) Price $i each.

In these parts is concluded Chapter 14, which gives a full description of
the Electricity section ; Chapter 15 describes the Horticulture and Forestry
section ; and Chapter 16 is commenced, showing exhibits of Mines, Mining,
Metallurgy. Too much cannot be said in praise of the very excellent illustra-
tions in these and earlier parts ; those relating to Horticulture and Forestry
are especially fine.

• Jarrold's Guide to Great Yarmouth and Neighbourhood.
Jarrold's Guide to Cromer and Neighbourhood. Cr. 8vo,
pp. 116 and 133. (London: Jarrold & Son. 1895.) Price 6d. each. '

Two handy and nicely illustrated little books which will be found useful to
the tourist.

The Great Eastern Railway Company's Tourist Guide to the
Continent. Edited by Percy Lindley. Cr. 8vo, pp. 158. (London: 30 Fleet
Street. 1895.) Price i/-

This will t)e found a handy book for the continental tourist. Among its
fresh features are a series of Continental Maps ; a special chapter on Holland
and its Exhibition, and Excursion round Amsterdam ; and a chapter " Dull
Useful Information," giving particulars as to the cost of Continental travel.

[ 452 ]

3n&ey IPol. F.

Page
Absorption of Organic Matter by

Plants 66

Address to Members of the Bath

Micro. Soc. - - - - 62
Adherence of Metals to Glass - 227
Agar-Agar, Filtiation of - - 106
Ages, The Ice - - - - 138
Air, Change of - - - - 408
Aluminium .... 109

Anhydrite, Artificial Production of 223
Aphaniptera .... ^^^

Aphides, Parasitic Enemies of the 33,

121, 254, 395
Aphis-Eating Neuroptera, Classifi-
cation of - - - - 402
Apochromatic Objectives for the

Microscope - - - - 91
Aquarium, The - - - - 96
Argillaceous Muds, Treatment of - 30
Acidians, Preservation of - - 338
Ascomycetes .... 409

Atmosphere, Another Constituent

of the - - - - 217

Bacillus buccalis maxim us - - 166
Bacillus crassus sputigenus - - i77
Bacteria of the Sputa and Crypto-

gamic Flora of the Mouth - 67,

161, 300, 417
Bacteriological Examination of

Blood ----- 224
Bath Micro. Soc, Address to - 62
Beginners in Microscopy Notes for 147
Benham's Artificial Spectrum Top 135
Biondi, The Fungus of - - 178

Blathwayt, Col. L., on Aphaniptera 345
Blood, Bacteriological Examina-
tion of - - - - - 224
Bodington, Mrs. A., Leaves from

my Note- Book - - - 155
Borofuchsin as a Stain for Tubercle

BacilU .... 225

British Fungus Flora - - - 409
British Hydrachnidcie - - 152, 298
Brooks, W. K., On the Origin of

the Oldest Fossils - - 269

Brown H. Langley, On the Deve-
lopment of the Germ Theory- 19
Bryan, G. H. , On Benham's Spec-
trum Top - - - -135

Page
Bryan, G. IL, On Relaxing Insects

for Cabinet - - . - 357

Cabinet, Relaxing Insects for 226,357

Canada Balsam Fir - - - 112
Cats and Rats in Cold Storage

Warehouse - - - - I55

Celloidin Sections, Fixing - - 106

Centipedes, Plabit of - - - I97
Centrosomes and Iron Hsematoxy-

lin 108

Change of Air .... 408

Chemical Activity of Sunlight - 160

Cherry-Tree, Denizens of an Old - i

Clarification, Some Remarks on - 204
Clayton, George, On Co-operation

in Plants .... 209

Coelenterates, Preservation of - 337

Compressor, Hodgson's - - 105

Co-operation in Plants - - - 209

Ctenophores, Preservation of - 338

Cycle of Life, A - - - - 45

Denizens of an Old Cherry-Tree - i

Development of the Germ Theory- 19

Diatomacere, Technology of the - 29

Diatoms, Extraction of - - 31

Diatoms, Staining and Fixing - 339

Discomycetes - - - - 415

Dust to Dust, From - - - 45

Echinoderms, Preservation of - 337

Eels, Vinegar - - - - 148

Embedding Medium - - - 106

Etching Fluid for Glass - - 224

Eyes, Pain in the - - - 154

Famines in India - - - - 18
Filtration of Agar- Agar - - 106
Fir, Canada Balsam - - - 1 1 2
Fish, The Paradise - - - I57
Fixing Celloidin Sections - - 106
Flora of the Wabash Valley, The - 220
Floscularia Hoodii - - - 291
Fossil Microbes - - - - 226
Fossils, Origin of the Oldest - 269
Freshwater, T. E., On Photograph-
ing Micro. Objects - - 286
Yxom Dust to Dust - - - 45
Fungi of Biondi, The - - - 178

INDEX.

453

Page

Fungi of Miller, The - - - 178

Fungi of the Mouth, Pathogenic - 175
Fungi of the Mouth, Stained with

Iodine - - - - - 173
Fungi of the Mouth, which may be

Cultivated - - - - 173

Fungi, Pathogenic, Cultivable - 177

Fungi, Pathogenic, Not Cultivable 176

Galton, F. , On Specific Stability - 359
Germ Theory, Development of the 19
Ghost Flower, The Indian - - 158
Glass, Adherence of, To Metals - 227
Glass, Etching Fluid for - - 224
Grand Falls of Labrador, The - 113

Hall, A. J., On the Physiology of

the Special Senses - - 139

Harkness, W. , On the Magnitude

of the Solar System - - 189

Heat, Radiation of - - - 134

Hodgson's Compressor - - 105

Holmes, Oliver Wendell, and the

Microscope - - - - 296

Hood, John-, on Floscularia Ploodii 291

How Young Spiders are Fed - 1 1 1

How the Musk Rat Breathes under

Ice 268

Hydrachnidre, British - - 152, 298

Hysteraceae ----- 409

Ice Ages, The
Impressions in Sulphur
India, Famines in
Indian Ghost-Flower, The
Influence of Light on Life

- I3«

- 227

- 18

- 158

- 233

Insects for Cabinets, Relaxing 226, 357
Insects, The Use of Parasitic and

Predaceous - - - . 222
Iron-Hoematoxylin and Centro-

somes - - - - - 108

James, F. J., On Lacquering Micro

Tubes, etc. - - - - 150
Japan, The Paradise Fish of - 157

Jodococcus vaginalis - - - 168
Jupiter, The Planet - - -32

Koch's Solution of Methylene Blue 223

Labrador, The Grand Falls of - 113

Lacquering Micro-Tubes, etc. - 150

Leaves from my Note-Book - 155

Leptothrix buccalis - - - 164

Leptothrix buccalis maxima - - 167

Leptothrix gigantea ■ - - 171

Page
Leptothrix buccalis. Morphology

and Biology of - - - 180

Life, A Cycle of - - - - 45
Light, The Influence of, on Life - 233
Limax maximus, Ookinesis in - 381

Magnitude of the Solar System - 189
Marine Animals, Preservation of - 336
Medium, An Embedding - - 106
Metals Adhering to Glass - - 227
Methylene Blue, Koch's Solution - 223
Micro-Fungi, The Study of - - 361
Micro - Organisms of Mouth,

Secondary - - - - 17 I
Micro-Organisms of the Teeth - 147
Micro. Tubes, etc., Lacquering - 150
Microbes, Fossil - - - - 226
Micrococcus tetragenus - - i77

Microscopes, Achromatic Objec-
tives for - - - - 91
Microscopes of 1894, The - - 324
Microscopical Purposes, New Clar-

ifier for ----- 204
Microscopical Technique 105, 223, 336
Microscopy, Notes for Beginners in 147
Microtome, Knife to Sharpen - 336
Miller, The Fungi of - - - 178
Molluscs and Brachiopods - - 438
Monotropa Unifolia - - - 158
Mounting, Styrax for - - - 107
Mouth, Fungi of, Stained with

Iodine 173

Mouth, Fungi of, which may be

Cultivated - - - - 173
Mouth, Pathogenic Fungi of - I75
Musk Rat, How it breathes under
Ice 268

Neuroptera, Aphis-eating, Classifi-
cation of - - - - 402
Note Book, Leaves from my - 155

Notes no, 226

Notes for Beginners in Microscopy 147

Objectives, Apochromatic - - 91
Ocean, Discovery of the Bottom

of the 269

Ookinesis in Limax maximus - 381
Organisms of the Mouth, Opinions

hitherto held on - - - 161

Pain in the Eyes - - - 154

Paradise Fish of Japan, The - 157

Parasitic Predacious Insects, The

Use of 222

Pathogenic Fungi of the Mouth - 175

;j47;:i4

454

INDEX.

Page
Pathological Casts, New Material

for no

Photographing Minute Objects by

the Microscope - - - 386
Physiology of the Special Senses - 139
Plants, Absorption of Organic

Matter by - - - - 66
Plants, Co-operation in - - 2C9

Plants growing at Great Elevations 61
Plants, Number of Species of - 227
Plants, Purification of Water by - in
Predacious and Parasitic Enemies

of the Aphides 33, 121, 254, 395
Pr-eparation of Tooth Sections - 198
Preparing Large & Thick Sections 226
Purification of Water by Green

Plants Ill

Radiation of Heat - - - 134
Rays of the Solar Spectrum - - 394
Relaxing Insects for Cabinet 226, 357
Reviews - - 114, 228, 340, 445
Reynolds, Dr. R. N., Notes for

Beginners .... 147
Royal Natural History, The - - 102

Saturn's Rings .... ^23
Schultze, E. A., on a Clarifier for

Micro. Purposes - - - 204
Sea Weeds, Preservation of - - 339
Sections, Celloidin, Fixing - - 106
Sections, Large and Thick, Pre-
paring 226

Senses, Physiology of the Special - 139

Sharpening a Microtome Knife - 336

Snow Crystals - - - - 88
Soar, C. D., on British Hydrach-

nidse - - - - 152, 298

Solar Spectrum, The Rays of - 394

Solar System, Magnitude of - 189

Soundings, Treatment of - - 29

Species of Plants, Number of - 227

Specific Stability, Questions on - 359

Spectrum Top, Benham's - - 135

Spiders, Young, How Fed - - in

Spirillum sputigenum - - - 168

Spirochoete dentium - - - 1 70
Sputa, Bacteria of the 67, 161, 300, 417

Sputa, Collecting and Preparing
Stain for Tubercle Bacilli
Staining and P'ixing Diatoms
Starch, Wheat, and Rye
Staphylococcus pyogenus albus
Streptococcus pyogenus
Stubbs, Rev. E. T., Address

Bath Micio. Soc. -
Styrax for Mounting
Sulphur, Impressions in
Sunlight, Chemical Activity of

to

Page

- 82

- 225

■ 339

- 107

■ 177

■ 177

62

107
227
160

Technique, Microscopical 105, 223, 336
Technology of the Diatomaceoe - 29
Teeth, Micro-Organisms of the - 147
Tempere, J, , On the Technology of

the Diatomaceae - - - 29
Thomson, W., On the Influence of

Light on Life - - - 233

Thomson, W., On the Study of

Micro-Fungi - - - - 361
Tolputt, W. B., On the Prepara-
tion of Tooth Sections - - 198
Tooth Sections, Preparation of - 198
Top, Benham's Artificial Spectrum 135
Torpedo Fish, The - - - 385
Tubercle Bacilli, Stain for - - 225
Turner, J. Sidney, On a Cycle of

Life 45

Vermes, Preservation of - - 338
Vicentini, F., On Bacteria of the

Mouth, etc. - 67, 161, 300, 417
Vine, C. A., On Predaceous and

Parasitic Enemies of Aphides- 33,

121, 254, 395
Vinegar Eels - - - - 148

Wabash Valley, The Flora of - 220
Washburn, F. L., On Ookinesis in

Limax maximus - - - 381
Water, Purification of, by Plants - in
Watkins, C. J., On the Denizens

of an Old Cherry Tree - - i
Weather-Charts - - - . 208
Weed, C. B., On the Use of Para-
sitic and Predaceous Insects - 222
Wheat and Rye Starch - - 107

INDEX.

455

1Re Views.

Page
1
- 340

120

118
446
230

Across the Common after Wild

Flowers
Adventure, Stirring Tales of Colo-
nial - - . .
Album of English and Welsh

Cathedrals
Angling and How to Angle -
Animal World, The
Animals, Study in the Evolution of 445
Annals of a Fishing Village - - 1 1 7
Annual of the Universal Medical

Sciences - - - - 119

Antiseptic Therapeutics - - 447

Arithmetic, McDougal's Higher

Grade - - - - - 114
Arithmetic Prize Papers - - 449
Around a Corn-field after Wild

Flowers . . . . ^40

Bacteriology, Directions for Labo-
ratory Work in -
Band of Mercy, The -
Battles of the 19th Century -
Bible, The Plants of the
Biology, Practical Lessons in Ele-
mentary . . . .
Biology, Outlines of - - -
Birds, A Chapter on - - -
Birds About Us, The -
Birds, A Dictionary of -
Birds of Great Britain, A Hand-
book to ....
Book of the Fair - - 231, 344,
Botany for Beginners, Practical
Botany, Laboratory Exercises in -
Botany, Object Lessons in -
British & Colonial Druggist, Diary
Buried Cities of Vesuvius

Carbon Printing - - - -
Carnivora, A Handbook to the
Cassell's New Technical Educator-
Cerebral Meningitis
Chemist and Druggist Diary -
Chess Openings - - -
Chess Problems - - -
Child's Pictorial, The -
Cholera - . . .
Common Things - - -
Consider the Heavens -

116
231
344

447

116
116

446

115
115

232

451

228

340
340
120

450

118

341
229,

344
447
119

451

451
120

447
117
446

Page
Darwinian Theory, Lectures on 1 17, 229
Diatomees, Texte et Tables - - 450
Dictionary, A New English - 114, 228,

343. 448
Dictionary, The Standard - - 343
Die Naturlichen Pflanzenfamilien - 116,

228, 341, 447
Diphtheria, Treatise on - - 447

Divining Rod, The - - - 117
Down the Lane and Back in Search

of Wild Flowers - -. - 340
Dreamy Mental States - - 448

Earth, The - - - -

Earth, The Planet

Electricity, Intro, to the Theory

of

European Butterflies and Moths

231, 344
Eye, The, in Relation to Health - 342
Eyesight and School Life - - 448

115
228

- 230
■IIS,

Fishes, British Freshwater
Flower of the Ocean, The
Friends in Fable -
From Spring to Fall

- 341

- 119

- 449

- 117

Games for Winter Evenings - - 120
Gamekeeper, Autobiography of an

English - - - - 344
Gardening, Amateur's Handbook of 228

Great Eastern Tourist's Guide - 451

Gynaecology, Landmarks in - - 119

Half-Hours with the Microscope - 116

Plealth, The Elements of - - 344

Herbal Simples - - - - 448

Hereafter and Judgment - - 118

Hidden Beauties of Nature - - 446

Holiday Tramps - - - - 344

In Sunny France - - - 344
Insects, A Manual for the Study of 341

Intensity Coils . . . - 229

Intestinal Diseases of Children - 447

Jarrold's Guide to Cromer - - 451

Jarrold's Guide to Gt. Yarmouth - 45 1

Laboratory Guide for the Dissec-
tion of the Cat - - - 445

456

INDEX.

Page
Laboratory Guide for the Bacte-
riologist .... 240
Lepidoptera, A Handbook to the - 232
Light from Plant Life - ■ - 446
Light, The Theory of - - - 342
Lone Inn, The - - - - 120

Magic-Lantern, The - - - 230
Mammalia, Handbook to British - 231
Marsupialia and Monotremata, A

Handbook to - - - 232

Massage, The Art of - - - 447
Mechanics, Elementary Text-Book

of ----- 44Q

Medical Annual, The - - - 230
Medical Sciences, Annual of the

Universal - - - - 119
Memories of Gospel Triumphs

among the Jews - - - 120
Microbes and Disease Demons - 448
Microscope, Half-Hours with the - 116
Microscopy, Practical - - - 341
Model Steam Engine - - - 232
Modern Climatic Treatment - - 447
Mollusca, Monograph of Land and

Fresh Water - - - 114

Monism - - - - - 118
Murche's Science Readers - 342, 445
Museae, Synopsis of the - - 228

Nature in Acadie - - - - 342

Nature Knowledge, Short Studies

in 343

Notable Answers to 1000 Questions 451

Open Air Studies

- 445

118

447
119

Parish Councils' Act
Pernicious Fevers
Photo-Micrography
Photographic Almanack, British

Journal 119

Photography, American Annual of 231
Photography, Intro, to the Science

and Practice of - - - 342
Photography, Beginner's Guide to- 229
Photography, Pinhole - - - 449
Physics, Lessons in Elementary - 342

Physiology for Beginners
Plants of the Bible
Plants, Practical Physiology of
Plants, The Story of the
Pocket Flora of Edinburgh -
Ponds and Rock Pools
Popular Science -
Primates, A Handbook of the
Primitive Man, The Story of

Page

- 230

- 447

- T16

- 447

- 115
115

- 229

- 231

- 343

Salt Water Hero, A - - - 120
School Method, A New - - 114
Science Progress - - 117, 232, 450
Sherlock Holmes, Adventures of - 344
Sound, a Text-Book of - - 229
Stirring Tales of Colonial Adven-
ture 120

Stories in a Shell - - - - 450

Story of the Stars - - - 232

Stroll in a Marsh in Search of

Wild Flowers - - 340

The Lone Inn - - - - 120
Theophrastus on Winds and

Weather Signs - - - 117

Theosophy, Outlines of - - 118
Through the Copse in Search of

Wild Flowers - - - 340
Travant d'Electrotherapie Gyne-

cologique . . . . 230

Trigonometry, Elementary - - 449

Vaccination Question, The - -119

Wayside and Woodland Blossoms - 341
Whooping Cough - - - 447
Wild Animals, Stories of - - 446
Winds and Weather Signs, Theo-
phrastus on - - - - 117
With the Woodlanders and By the

Tide 117

Woodside, Burnside, Hillside, and

Marsh 118

Year- Book of Scientific Societies - 445

Zoology, Intro, to the Study of - 446

C. SEERS & SON, PRINTERS, ARGYLE STREET, BATH.

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