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Bs BEvakl MENT OF AGRICULTURE:
BUREAU OF PLANT INDUSTRY— BULLETIN NO. 100.

B. T. GALLOWAY, Chief of Bureau.

MISCELLANEOUS PAPERS.

I. CRANBERRY SPRAYING EXPERIMENTS IN 1905.
By C. L. SHEAR, Pathologist.

Il. THE WRAPPING OF APPLE GRAFTS AND ITS RELATION TO THE
CROWN-GALL DISEASE. :
By HERMANN VON SCHRENK, Special Agent,
and GEORGE G. HEDGCOCK, Assistant.
III. GARLICKY WHEAT.
By J. W. T. DUVEL, Assistant.

IV. METHODS OF TESTING THE BURNING QUALITY OF CIGAR TOBACCO.
By WIGHTMAN W. GARNER, Scientific Assistant.

VY. THE DRUG KNOWN AS PINKROOT.
‘By W. W. STOCKBERGER, Expert.

VI. ORCHARD GRASS.
By R. A. OAKLEY, Assistant Agriculturist.

VIL. THE EFFECT OF COPPER UPON WATER BACTERIA.
By KARL F. KELLERMAN, Physiologist,
and T. D. BECKWITH, Scientific Assistant.

VIII. CONDITIONS AFFECTING LEGUME INOCULATION.

By KARL F. KELLERMAN, Physiologist,
and T. R. ROBINSON, Assistant Physiologist.

IssuED APRIL 25, 1907.

WASHINGTON:
GOVERNMENT PRINTING OFFICE,

BUREAU OF PLANT INDUSTRY.

Pathologist and Physiologist, and Chief of Bureau, Beverly T. Galloway.

Pathologist and Physiologist, and Assistant Chief of Bureau, Albert F. Woods.

Laboratory of Plant Pathology, Erwin F. Smith, Pathologist in Charge.

Investigations of Diseases of Fruits, Merton B. Waite, Pathologist in Charge.

Plant Breeding Investigations, Herbert J. Webber, Physiologist in Charge.

Plant Life History Investigations, Walter T. Swingle, Physiologist in Charge.

Soil Bacteriology and Water Purification Investigations, Karl F. Kellerman, Physiologist in Charge.

Bionomic Investigations of Tropical and Subtropical Plants, Orator F. Cook, Bionomist in Charge.

Drug and Poisonous Plant Investigations and Tea Culture Investigations, Rodney H. True, Physiologist
in Charge.

Physical Laboratory, Lyman J. Briggs, Physicist in Charge.

Taxonomic Investigations, Frederick VY. Coville, Botanist in Charge.

Farm Management Investigations, William J. Spillman, Agriculturist in Charge.

Grain Investigations, Mark A. Carleton, Cerealist in Charge.

Arlington Experimental Farm, Lee C. Corbett, Horticulturist in Charge.

Sugar-Beet Investigations, Charles O. Townsend, Pathologist in Charge.

Western Agricultural Extension Investigations, Carl 8. Scofield, Agriculturist in Charge.

Dry Land Agriculture Investigations, E. Channing Chilcott, Agriculturist in Charge.

Pomological Collections, Gustavus B. Brackett, Pomologist in Charge.

Field Investigations in Pomology, William A. Taylor and G. Harold Powell, Pomologists in Charge.

Experimental Gardens and Grounds, EdAward M. Byrnes, Superintendent.

Seed and Plant Introduction, David Fairchild, Agricultural Explorer in Charge.

Forage Crop Investigations, Charles V. Piper, Agrostologist in Charge.

Seed Laboratory, Edgar Brown, Botanist in Charge.

Grain Standardization, John D. Shanahan, Expert in Charge.

Mississippi Valley Laboratory, St. Louis, Mo., Hermann von Schrenk, Expert in Charge.

Subtropical Laboratory and Garden, Miami, Fla., Ernst A. Bessey, Pathologist in Charge.

Plant Introduction Garden, Chico, Cal., Palemon H. Dorsett, Pathologist in Charge.

Cotton Culture Farms, Seaman A. Knapp, Lake Charles, La., Special Agent in Charge,

Editor, J. E. Rockwell.
Chief Clerk, James E. Jones.

CO NEEN Es.”

Page.
Cranbernysspra vine experimentsnmilO0D) sacs = sees cos oo ee caw aces d
in GEROGU CTO Meet ee ee Ae tO eer ee sr Sos Sn ww ewe 7
SprMyinocaldelts Pesiliisene me sate see ee ene eee ee oh Sk sce 8
iimportanceoearhyapplicationces spss a ee cle oo oa eo ses 9
Bifects ol spraying plants: when amtulllbloome =... 2... 4-5-1 2-2 2 ae 10
Keeping qualities of sprayed and unsprayed fruit...............-----.--- 10
Costand recommendations \ssernr Sie te tee ee ss ih ea ee le 11
The wrapping of apple grafts and its relation to the crown-gall disease - ------ 13
JOMPROCIOR OMS BAS See eee ee rR OES ESE Doe ae aCe ee Mie rein apes eter ae eee 18
PAC COMMIS Ie XPCTIMNC MGS aes oe ersee Poy ee ioe pre es $i toca te 14
Meme xO fe Wa OL Seer ees poy ee ac ee Sr ays ae 15
Garantisple tte umwywina pe deserts tee ee cae re ene ene es y e aiel it ee 16
esti (Se oles witett Olin Cus pe ee rns eee eon ee Geese) eee 16
itectipongthesumioms tea ee ke SE i a as NE ea 16
Bitectonkerown-co | onmation 224... ase ese he ss Se ope 18
VECO MMM CMC AGLON Sie eee ee aa Sen ee ee ey gr een oy BREN. Se {8
SUOERETT OLN WO) AMDT ESSV CYAN OVE esas 5 ee ee Sea ree Sere ee ae 19
UUTMONATAY Se SS ee RS SE ey at a lo er 20
Garlic key ae wale a beset ee ee Os SSNS a Se a ee Lis Re 21
IN ROCKUCELO Mee ee encase to ee a ha se eee i ohana eae 21
Wilea tic oman cy oan Cea ae apo se ee he et 2 ee See Siren 21
Experimentsam separaring carlic trom wheat: .2+.- 22 32...552- 5-2 -5- 22
OO aS ER CSS OSE SS Se ten SER ETRE Te ir Cay ee ee paren ls Aiaeee ace ets 23
BG) eb epee ape rare a eee ae ie nate er Ses ana ea 24
NOt Cases oe at OSE Sas os pe AS i CO oer aap SEAR Yo 25
The total cost of drying and cleaning garlicky wheat................---- 26
he Met Cost OlenemoviNn se CAvliCe a. seo sss cee 2 = os ee see 28
The effect of the drying on the milling qualities of the grain.......-...-- 28
The effect of the drying on the vitality of the wheat .................--- 29
Machimenysuscd tomdrying and cleaning ==... 2. <2-25.-5-2s544-- 5252252 30
SCOOT PW ek oes I A SI Ne II ae ee eee ee Rees 30
Methods of testing the burning quality of cigar tobacco ................----- 31
LEONE SEUBTCETTS Ss i se Re re ke keg a a eee ae 31

RY GG SYMONS TaN EIT Bese ae ea Rat a 3
The effects of the filler, the binder, and the wrapper on the burn of the cigar. 35
Testing the capacity for holding fire and the evenness of the burn ......- 37
Wesiimesehnesburnoncicar-tillerstOMACCOmac se 4c a= re elec cae acne cess 40
piivesdiisaknommsasipiMikrOOteacs as acess Ae se Sask Swe aces euas 41
IMGROGUICLIO NI yo eres eens Gare ates ee eter tee We aL Re ee oe oe 4]
iradeaarieticsiols pinknoote ss =212 a. S22 dee Sn oct alge tet 41
HG emuiGya OlCMCIssUstIbULese ese ene ek eo koe. belsc cease 42

aThe eight papers constituting this bulletin were issued in separate form on February 7, February
28, April 5, June 9, October 9, October 8, October 20, and November 30, 1906, respectively.
100 3

4 CONTENTS.

The drug known as pinkroot—Continued.
Minor adulterants 2555 * ae. 8 eee
; Methods of distinguishing pinkroot from its substitutes ...............--
Orchard. grass '..23 255) See sok se a ee Sha gee
Introd wetions 2 oi eee Es ae a ie aan

Seeding 6 ore. s 18 2 See Sa is Se
Mixtures-wath redsclovers. 1) 2 as ee ei ee
Mixtures withtother erassest5.0 2 os oe eee
Life of meadows) 22 42 os ais 5 Se are a a

Wises err, welt ee ec se a are eee .

Ela yee 2 sa a eel ese Bee eso eee ee ee eeee ey SME 2 S

Seed 5 its ee eae gees ee
Harvestins the'seed (crop 252220 be see ee ee ee
Thrashine: 26222 225 Soe Se ee es ee ee eee
Handling theatterorowth.22 2a ee eee
Value‘of the straw i252 225.0 sk eis ioe
Weeds in ‘orchard grass seed felds2 322 ee ee
Other grasses in fields intended for seed.............-..-.-----:
Summary esc 2 Oe A as ee ee eee eee
Fhe cfiect of copper upon water bacteria = 2 ee ee
Introduction: oc 2 es sae eo cs 3s Pee ee ee ee eee
Resistance: Oivanous bacteriam == aac te ss ee | ae ee ae eee
Effect of carbon dioxid on viability of Bacillus coli and Bacillus typhi...
Copper sulfate and: filtratiome@ 42. > 3 ee ee eee eee
Conditions attecting lesume moculatrone 2 ees oe ee ee
Introduction... 2s. soe owe ce eee
Use of limes. eu Ses. Se ee eee ee
Effect of soil-conditions upon bacteria = 25 2 oe ee
Effect of heavy inoculation {22 = 22. sce a et os eee
Effect-of aeration). 222 Sree so oe ee eee
Associative action: of bacteria: 22220 2S ero ieee ree ey ee ae
SUMAMMIAPY oo le ee Se ee he ae ee ree

100

49

Or Ot Ot Ot Gt OV
bnpre KF So ©

Se)

Or on on
WSs

Or
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1D Dog
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(8) weet I ST SY GSP
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(oe)
Co INS

PiateE I.
We

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LV:
NV
VI.
WATE

VII.

ID.

PIA Us she A (ELON S:.

PLATES.

Wheat kernels and the aerial bulblets of wild garlic. Natural size.
Fig. 1.—4A, 1-pound sample of garlicky wheat, Lot A, as received; B,
amount of garlic in l-pound sample when received, 2.17 per cent;
C, amount of garlic remaining in 1-pound sample after drying and
cleaning, 0.05 per cent. Fig. 2.—A, 1-pound sample of garlicky
wheat, Lot B, as received; B, amount of garlic in 1-pound sample
when received, 0.56 per cent; C, amount of garlic in 1-pound sam-
ple after drying and cleaning, 0.06 per cent. Fi
sample of garlicky wheat, Lot C, as received; 6, amount of garlic
in 1-pound sample when received, 2.04 per cent; C, amount of gar-
lic remaining in 1-pound sample after drying and cleaning, 0.16
JUSTE LONG SS SER Ge ESS a a aN ee eg
Variation in burn of wrappers due to different fillers ..__....------
Variation in burn of fillers due to different wrappers and binders.- - -
PAM KPOOtH ES PIGEON OTN ANGCICO Ma.) sas So ces ee ene Soe See ee
East Tennessee pinkroot (Ruellia ciliosa Pursh) .......-..---------
Fig. 1.—Harvesting orchard grass for seed. Fig. 2.—Method of
shocking orchard grass; shocks showing bands at top- -----------
Pots of red clover, showing the effect of lime on a soil unfavorable
Loehrer TOvytneOlClOVGr =< s a2 oe aoe eae ee eee
Fig. 1.—Pots of garden peas, showing the effect of—aeration on
growth. Fig. 2.—The garden peas illustrated in figure 1, showing
EuereneCt.OF aeravion on noduledormation 9. = 2822" 2222s ==

TEXT FIGURES.

Fra. 1. The apparatus used in the cranberry spraying experiments ----------

H OO ho

o> ON

100

. Apparatus for testing the burning quality of cigars .-.---.-----------
. Apparatus for testing the burning quality of wrapper tobacco ~~ - -----
. Construction of form on which leat is wrapped for use in apparatus

Sh OmpnMiN stun Cr ee ea ay oh ee meee eae See SS bcos = ee

. Cross section of the root of Spigelia marilandica Li -.-----------------
- Cross section of the root of Ruela ciliosa Pursh .-.-..-._-.-----~-----

Page.
2p

80

B. P. I.—200. Vie PoP r= 1505

MISGELEANE OS PAPERS.

l—CRANBERKY SPRAYING EXPERIMENTS IN.1905.

By C. L. SHear, Pathologist.

INTRODUCTION.

In Farmers’ Bulletin No. 221% a brief account was given of cranberry
diseases, and also the results of spraying experiments with Bordeaux
mixture. The results in 1904 were not entirely satisfactory. This was
not due, however, to the inefficiency of Bordeaux mixture, but to cir-
cumstances which prevented the applications being made at proper
intervals. The results obtained in 1904 showed an average of 21.7 per
cent of rotten berries on the sprayed plats, as compared with an average
of 76.8 per cent rotten on the unsprayed check plats. Considering the
unsatisfactory manner in which the Bordeaux mixture was applied, the

prediction was ventured that it would be possible with more thorough
treatment to reduce the loss from rot to 10 or 15 per cent. ‘The results
obtained in 1905 have more than justified this prediction.

The experiments were conducted on what is known as the Bunker
Hill bog at Whitesville, N. J., which is in charge of Mr. James D.
Holman, the same plats being used as in 1904, with the addition of a
small area not heretofore sprayed. This bog was selected because the
fruit had in former years been almost entirely destroyed by disease.
The water was drained from the bog May 10-12. It is the usual prac-
tice of cranberry growers to flood bogs for twenty-four hours during the
first week in June, in order to destroy insects. In these experiments
it was planned to spray part of the experimental plats before this second
flooding and part immediately afterwards, in order to determine the
necessity or desirability of spraying before this flooding. The water
supply of the bog was, however, insufficient to flood it at the usual
time, and it was not done.

The spraying apparatus used was a barrel and force pump fitted with
two lengths of half-inch hose, each length provided with an extension
rod and two Vermorel nozzles. The apparatus was driven about the
bog in a low-bodied spring wagon, as shown in figure 1.

“Farmers’ Bulletin No. 221, U. S. Dept. of Agriculture, ‘‘ Fungous Diseases of the
Cranberry. ”’
100—1I

~]

8 MISCELLANEOUS PAPERS.

The Bordeaux mixture used consisted of 6 pounds of copper sulphate
(bluestone) and 6 pounds of fresh stone lime to 50 gallons of water, to
which was also added 45 pounds of commercial resin-fishoil soap. The
addition of this soap has been found to be indispensable, as Bordeaux
mixture will not spread over and adhere satisfactorily to the glossy sur-
face of the cranberry leaves and fruit without it. Heretofore this soap
has been made as it was needed for use. Its manufacture was not
an altogether pleasant operation. Now that the soap is being manu-
factured and placed on the market at about 3 cents per pound, it is
cheaper and much more convenient to purchase it than to make it.

SPRAYING AND ITS RESULTS.

a

The sprayed plats were numbered 3, 5, 6, 7, and 9, the plats between
being left as checks. Plats 3 and 7 were sprayed five times, as follows:
May 19, June 22-23, July 14-17, July 31-August 1, and August 15-17.
On September 8, accurate counts were made of all the diseased and
sound berries on small areas, showing the average condition of the
berries on the sprayed plats; also of equal areas, showing the average

Fic. 1.—The apparatus used in the cranberry spraying experiments.

condition of the berries on the check plats. Plat 3 gave 3.23 per cent
of rotten berries, plat 7 gave 8.8 per cent of rotten fruit, check plat 2
showed 91 per cent of rotten fruit, and check plat 8 gave 91.53 per cent
of rotten berries, giving an average of a fraction over 6 per cent of rotten
fruit for the sprayed plats and a little more than 91 per cent for the
unsprayed plats. On these two plats it will be noted that the first
application was made on May 19, when the vines had but just com-
100—1

CRANBERRY SPRAYING EXPERIMENTS IN 1905. 9

menced to put out new growth. This application was the one men-
tioned as being made before the usual flooding for insects.

Plats 5 and 9 were sprayed five times, as follows: June 2, June 22-23,
July 14-17, July 31-August 1, and August 15-17. On June 2, when
the first application was made to these plats, there was a good growth
of young shoots and leaves.. Counts of fruit on small areas, as in the
preceding case, gave the following results: Sprayed plat 5, 2.62 per
cent of rotten berries; sprayed plat 9, 2.1 per cent of rotten fruit; check
plat 4, 91.8 per cent rotten; check plat 10, 93.5 per cent rotten, giving
-an average of 2.36 per cent of rotten berries on the sprayed plats and
92.6 per cent of rotten fruit on the unsprayed plats. There was very
little difference in the amount of rot on this series of plats and that on
the series mentioned in the preceding paragraph.

Plat 6 was sprayed but three times, as follows: July 14-17, July 31-
August 1, and August 15-17. Counts made, as in the previous cases,
on September 8, gave the following results: Sprayed plat, 18.3 per cent
of rotten berries; check plat, 91.53 per cent of rotten fruit. It may
also be added that a greater number of the berries from this sprayed
plat decayed before they were ready for shipment than was the case

with the fruit from the plats which received five applications.

' The fruit from an area of 1,048 square feet, showing average condi-
tion of fruit on sprayed plat 7, was carefully hand picked and produced
3 bushels of sound fruit, which is at the rate of about 125 bushels per
acre. The same area from check plat 8, showing the average condi-
tion of fruit, gave a scanty peck, or at the rate of about 10;°; bushels
per acre. In other words, there was twelve times as much sound
fruit on the sprayed as on the unsprayed plat, or a saving of over 100
bushels per acre.

Besides our purely experimental plats, several acres upon another
cranberry bog known as ‘‘Long Swamp” were sprayed by Mr. Holman.
One portion was sprayed five times on the following dates: June 6-10,
June 26-28, July 18-21, August 2-4, and August 18-19. One part was
sprayed only four times. The first plat, which was also sprayed in
1904, was estimated to have from 80 to 100 per cent of the fruit sound
on September 15. On the area sprayed only in 1905 it was estimated
that from 70 to 90 per cent of the fruit was sound. On the plat which
received the first four applications only, the fruit showed somewhat
more rot than on the other plats at picking time. The fruit on these
plats had in former years been almost entirely destroyed by rot.

IMPORTANCE OF EARLY APPLICATIONS.

The difference in the appearance of the fruit on the sprayed and
unsprayed plats was very marked by the middle of July. On the
unsprayed plats a large proportion of the fruit was blasted, owing to the

100—1

10 MISCELLANEOUS PAPERS.

early attack of the scald fungus (Guignardia), while on the sprayed plats
but little blasted fruit was to be seen. _ In many cases at least one-half
of the fruit is destroyed by blasting, the young fruits being attacked
by the fungus at about the time the blossoms begin to fall. In order
to prevent this, one of the applications of Bordeaux mixture should be
made immediately after the vines have reached their maximum flowering
stage, as a delay of a week at this time may make a difference of from
25 to 50 per cent in the amount of fruit destroyed by blasting.

A very striking illustration of this fact was observed upon another
bog where one plat had been sprayed on July 1 and another adjoining
was not sprayed until July 8. On the plat sprayed on July 1, when
the vines had just reached their maximum flowering condition, but
very little blasted fruit could be found, whereas on the plat which had
been sprayed on July 8 about one-half of the fruit had been blasted.
This and other observations indicate the exceedingly great importance
of prompt and thorough early applications of the fungicide. In case
the bog to be sprayed is flooded for insects early in June, the first
application of Bordeaux mixture should be made within a day or two
after the water is removed, the second application just as the plants
begin flowering, and the third just after the majority of the blossoms
have appeared, which in ordinary seasons will be about the first of July.

EFFECT OF SPRAYING PLANTS WHEN IN FULL BLOOM.

In order to determine whether any injury would result from spraying
the plants while in bloom, part of one plat was sprayed when in full
bloom, and the amount of fruit which set upon this plat was carefully
compared with that on adjoining plats which had not been sprayed.
No difference could be noted in the amount of fruit on the sprayed and
on the unsprayed plats. In addition, certain bunches of vines were
dipped in Bordeaux mixture when in full bloom, but without any
apparent injury to the fruit. From our observations and experiments
it does not appear that there is much danger of loss from spraying vines
while in bloom. What little loss might possibly arise from this cause
would be very slight compared with the amount of loss from blasted
fruit in case the spraying was delayed too long.

KEEPING QUALITIES OF SPRAYED AND UNSPRAYED FRUIT.

A comparison of the sprayed and unsprayed fruit at the time of
picking does not give an exact idea of the amount of profit derived
from the treatment, as there was a much greater loss of unsprayed than
of sprayed fruit between the time of picking and the time the berries
were marketed.

In order to compare the keeping qualities of the sprayed and
unsprayed fruit, as well as unsprayed fruit which had been treated

100—1

CRANBERRY SPRAYING EXPERIMENTS IN 1905. i

with a solution of copper sulphate (1 part to 1,000 of water), 3,600
berries, perfectly sound so far as could be seen from external appear-
ance, were selected from fruit picked on September 18,1905. Of these,
1,200 were from the sprayed plats and the remainder from the unsprayed
check plats. These berries were kept in glass dishes in the laboratory
and counted each week, in order to determine the amount of disease
which developed. On October 18, about the time the fruit from the
bog was marketed, 9.8 per cent of the sprayed fruit showed diseased
berries, while 38.1 per cent of the unsprayed fruit and 37.4 per cent of
the unsprayed fruit which had been treated with the copper-sulphate
solution were diseased. In other words, four times as much of the
unsprayed fruit decayed between the time of picking and marketing as
of the sprayed fruit. 7

Parts of the check plats which were worth picking were picked by
hand and the fruit kept separate. This fruit was sorted for shipment
on October 15, 1905, when from 85 to 90 per cent of it was rotten. Mr.
Holman states that 40 per cent of all the unsprayed berries from Bun-
ker Hill bog decayed between the time of picking and marketing. No
treatment of the berries with fungicides after_picking is likely to give
satisfactory results, as we have found that the decay which occurs in
storage does not arise from germs which are on the surface of the fruit
at the time it is picked, but apparently from a dormant form of the
fungus already within the berries, where it is awaiting favorable con-
ditions for development.

As the time for picking approached, so much of the Bordeaux mix-
ture adhered to the sprayed fruit that it was feared enough might be
present when the berries were marketed to interfere with their sale.
This, however, did not prove to be the case, as the greater portion of
the mixture was removed from the fruit during the processes of pick-
ing, sorting, and preparing the fruit for market.

As the result of three years’ spraying experiments, it is safe to say
that by the proper use of Bordeaux mixture the loss from fungous dis-
eases can be reduced to 10 per cent or less. The loss may be slightly
more the first year a badly diseased bog is treated, as the benefit, as
shown in these experiments, is greater the second year than the first,
and is evident not only in the prevention of scald and rot of the fruit,
but in the general improvement, thriftiness, and productiveness of the
vines. Bordeaux mixture has also been applied with very beneficial
results to young vines not yet in bearing, the leaves of which were
badly affected by the scald fungus.

COST AND RECOMMENDATIONS.

The cost of the spraying as it was done in these experiments averaged
from $15 to $20 an acre, the mixture being applied at the rate of four
100—1

ILS MISCELLANEOUS PAPERS.

barrels, or 200 gallons, an acre at each application, making for the five
applications a total of 1,000 gallons to the acre.

In undertaking the application of Bordeaux mixture it is necessary
that all material and apparatus be in perfect readiness before the time
to begin the work, and nothing should be allowed to interfere with the
application of the fungicide at proper intervals; otherwise, the results
will be unsatisfactory, and the remedy is likely to be unjustly con-
demned.

The necessity for care and thoroughness in the preparation and appli-
cation of the mixture must also be strongly emphasized. The mixture
should be made as described in Farmers’ Bulletin No. 221, using only |
good, fresh stone lime and adding resin-fishoil soap. A good nozzle
(the Vermorel type is best) should be used and the vines very thor-
oughly covered at each spraying. Four barrels of the mixture to the
acre are ordinarily sufficient, but where the vines are very dense and
heavy five barrels may be necessary. Where there is an excessive
growth of vines, it will be found advantageous to rake them witha
knife rake and thin them out, as is frequently done in order to prepare
a bog for picking with scoops.

100—1

B. P. I.—208.

II—THE WRAPPING OF APPLE GRAFTS AND ITS
RELATION TO THE CROWN-GALL DISEASE.

By HERMANN VON SCHRENK, Special Agent in Charge of the Mississippi Valley Laboratory,
and GrorRGE G. Hepacock, Assistant in Pathology.

INTRODUCTION.

The crown-gall disease of apple trees, as indicated in a recent pub-
lication of the Bureau of Plant Industry,” appears in three distinct
types—the hard crown-gall, the soft crown-gall, and the hairy-root
forms. While the hairy-root disease of apples has usually been con-
sidered a type of the crown-gall disease, it in reality is an entirely
different trouble, with manifestations which are not in the least like
those met with in the true crown-gall disease. The soft type of crown-
gall on the apple has not yet been clearly differentiated from the hard
type, and in the following discussion the two are considered as one.

The knots which characterize the crown-gall disease of the apple
usually appear at some point, either on the root piece or on the scion,
where the two are united; that is, the gall may form at the end of the
tongue of either the scion or root piece, or at any point where either
piece has been wounded. This fact is one commonly recognized by
all nurserymen and scientific workers who have studied this disease.
About 90 per cent of these knots will appear on the end of the scion
piece. The exact cause of the formation of the gall is as yet somewhat
uncertain. It would seem, however, that, whatever the cause, the
point most exposed to the disturbing factor, whether it be due to a
fungus, to bacteria, or to soil oratmospheric conditions, is the junction
of the scion and root piece.

When the newly made grafts are laid away in the grafting cellar
either in sawdust, excelsior, moss, or other bedding material, callous
tissue begins to form on the cut surfaces of both scion and root piece.
This callous tissue from the two pieces will in time fill the intervening
spaces between the surfaces of the scion and the root piece, and ulti-
mately the root callus and the scion callus will join. Where the root
piece and the scion are of exactly the same size and where they are
united so as to fit exactly; a very perfect union will take place. Where

« Bulletin No. 90, Part II, Bureau of Plant Industry, U. 8. Dept. of Agriculture,
“ The Crown-Gall and Hairy-Root Diseases of the Apple Tree,’’ 1905.
100—11 13

14 MISCELLANEOUS PAPERS.

there is a difference in size between the root piece and the scion, or
where they are more or less imperfectly fitted, as is almost always the
case In commercial grafts, the callus formed by the scion and the root
piece will not always meet along equal planes. In these cases there
will be a tendency for the callus forming on any surface of either piece
which is not in direct contact with an opposite surface (no matter how
small this surface may be) to grow out from this surface, either later-
ally or down or up, into the air, with nothing to prevent its growing
into small lumps, which may reach considerable size. Very frequently
the pressure exerted by the growing callus will push the tongue of the
graft outward. <A thick cushion of callus will then form between the
scion and root piece.

The object of all grafting should be to bring about as rapid a union
between the two grafted parts as possible, with the smallest possible
period during which an open wound is allowed to remain into which
disturbing factors may enter. With this in mind, a number of experi-
ments were made during the past year, the specific objects of which
were to confine the formation of callus as far as possible to the spaces
between the root and scion pieces, thereby bringing about a closer and
more effective union and reducing the chances for the entrance of
possible disturbing factors.

—- It is intimated that the formation of the hard and soft types of apple
crown-gall may be due either to a proliferation of callous tissue in cases
where an uneven union is taking place and where the callus has had a
chance to grow out laterally in an unrestricted manner, or to fungi,
bacteria, or unfavorable soil or atmospheric conditions. Whatever the
cause, the making of a perfect union in the shortest possible time may
serve to prevent the trouble almost wholly if the first explanation given
be the cause, and at least largely remove the danger of a possible
infection if the second explanation is found to hold good.

ACCOUNT OF EXPERIMENTS.

In order to confine the formation of the callus, a number of grafts
were wrapped with various materials during the winter of 1904-5. The
wrapping idea is no new one, because cloth and paper were used by
nurserymen many years ago in connection with various types of root
and top grafting. At the present time cloth and paper are used very
little, because the system of thread wrapping will givea larger number
of grafts in a given period of time. The materials used in our ex-
periments were cloth, thin sheet rubber (dental rubber), and waxed
paper. In addition to this, grafts were made with plain thread
and waxed thread, and some grafts were wrapped with plain thread
and afterwards the whole union was covered with grafting wax.
One series of grafts was made without any wrapping of cloth or

100—II,

WRAPPING APPLE GRAFTS AND ITS RELATION TO CROWN-GALL. 15D

thread whatever, the pieces being simply fitted together with
care. All grafts made were of the type known as tongue or whip
grafts. The work was done by an expert, so that all of
the grafts may be considered as especially well made. No. 1 Kan-
sas roots and a selected lot of scions of the following varieties were
used: Winesap, York Imperial, Wealthy, Missouri, and Northern Spy.
The grafts were made in February, 1905. They were stored in chopped
excelsior for about six weeks, were then planted in eight different locali-
ties in Missouri, Illinois, lowa, Nebraska, Kansas, and Arkansas, and
given the usual cultivation during the summer. All showed a fair stand
in November, 1905. Some of the grafts were dug in November, and
December, 1905, one-third of the total number planted in five test plats
in four States being dug. The results obtained are given later.

MANNER OF WRAPPING. =

The manner in which the wrapping was made and the material used
may be briefly described as follows:

Cloth.—The cloth used was a cheap black calico of the poorest
grade obtainable in the market. This was torn into strips 1 inch wide
and 4 or 5 inches long. After the graft was made, one end of the cloth
was dipped for one-half inch into hot melted grafting wax. Starting
with the other end, the cloth was then wrapped tightly around the scion
and the free waxed end pressed down. This completed the operation.

Rubber.—TVhe rubber used was of a quality similar to dental rubber,
which is also frequently used for insulating wires. It was bought in
rolls 1 inch wide, and was cut off in such lengths as were necessary to
completely envelop the union. The rubber was usually wrapped so as
to go around the union twice, and the free end was fastened with rubber
cement applied with a brush.

Waxed paper.—Sheets of ordinary unglazed printers’ paper were
waxed on one side by coating them with hot grafting wax applied with
a paint brush. They were then cut into inch strips, i0 to 20 sheets
being cut at one time, and these again into strips about 4 or 5 inches
long. One paper strip was then wrapped around the union, the waxed
side toward the graft, the free end being stuck down by pressing it on.

Plain thread.—The thread used for the ordinary grafts was a
machine cotton, No. 9.

Waxed thread.—Yhe thread used was a machine cotton, No. 28.
This thread was soaked in hot grafting wax until thoroughly penetrated
and was then allowed to drain while hot. ,

Plain thread with union waced.—These were ordinary grafts made
with plain thread, wrapped as previously described, and then coated
with melted grafting wax nearly at the point of hardening.

100—U

16 MISCELLANEOUS PAPERS.

GRAFTS LEFT UNWRAPPED.

The grafts left without wrapping of any kind were made with special
care, so that when the roots and scions were joined they remained
firmly united.

RESULTS OF WRAPPING.

After digging the grafts, a careful examination of the various series
was made to determine the effect of the wrapping on the union and on
the presence or absence of crown-gall formation.

The following table shows the number of apple trees dug, the char-
acter of the wrapping, and the number and percentage of smooth trees
and rough trees, the latter class including all trees which were found
to have crown-gall, irregular callus, or hairy-root formations:

TABLE 1.—Comparison of smooth trees and rough trees resulting when different methods
of grafting were used.

Total Smooth trees. | Rough trees.
Kind of wrapping. —|
number. Number. | Per cent.; Number. | Per cent.
R |

10 CV eee arn AEE tis SSA OR Maas Son bOboraosde 675 584 86.5 91 By 65
CLOTHE ees Eee ee oe ae. oe eae acetone 709 604 | 85.1 105 14.9
Wie xe Gr papenenne tcc ussee cites ate smyaiscins tise or 671 474 70. 6 | 197 29. 4
Blaimet hens os sates ee se ee) Pas Oo ee 645 442 68.5 203 Bul 51)
Wiese dathinea carrer fase ee secirs tonic versinc siete SESE 675 430 63. 7 245 36.3
Plain thread with union waxed ................... 402 178 44,2 224 55.8
UM Wire ppe diese Aen oes Seca Same eteeeiepacrere 569 312 | 54.8 257 45, 2

Two series of facts may be deduced from this table—
(1) The effect of the various kinds of wrapping on the smoothness
of the union.
(2) The effect of wrapping on the presence or absence of crown-gall
formations.
EFFECT UPON THE UNION.

Some brief notes on the effect of the wrapping on the union follow.
By a smooth graft is meant one which shows no uneven or irregular
masses of callus. In the smooth grafts all parts are firmly united, so
that no ridge or roughness is felt when the union is rubbed with the
fingers. The grafts were graded with the greatest care.

Cloth.—When the grafts were planted in the spring the cloth was
usually intact. When dug in the autumn it had almost entirely rotted
away on all grafts. The union which resulted under. the cloth was
generally smooth and very even. In many cases it was difficult to
detect the original position of the scion and root parts. The cloth had
evidently remained in position long enough to thoroughly confine the
callus to the spaces between the wounded surfaces.

Rubber.—When the grafts were planted the rubber wrapping was

wholly intact. When dug the rubber was still found around the union
100—11 .

WRAPPING APPLE GRAFTS AND ITS RELATION TO CROWN-GALL. 17

in the majority of cases. It had, however, exerted no injurious effect,
because, as the young trees had grown in diameter, the rubber had
expanded. The roots had frequently punctured the rubber freely.
In other words, the rubber had in no way retarded the growth. The
unions formed under the rubber were smooth and even; in fact, they
were the most perfect of all those formed in the experiment. The
rubber. covering was practically waterproof. So perfect were the
unions that in many cases it was possible to detect the line of demar-
cation between the root and scion only by the difference in color.

Waxed paper.—W hen planted in the spring the waxed paper had not
rotted, but it had a tendency to become unrolled, due probably to too
much oil in the wax. When dug in the autumn the paper had mostly
disappeared. The grafts showed many smooth trees, but the percentage
was not nearly so large as in the case of those wrapped with rubber or
cloth. Attention should be called to the fact that in all grafts where
wax was used the wax itself seemed to exert an unfavorable effect on
the union, and the writers are inclined to discourage its use wherever
it comes into direct contact with wounded surfaces.

Plain thread.—W hen planted in the spring the plain thread had in
many instances entirely rotted away. The grafts when dug showed
many callus proliferations. The percentage of smooth grafts was low
when compared with rubber or cloth wrappings. The results were
about as good as those secured by the use of waxed paper wrapping,
and a little better than those obtained with waxed thread.

Waxed thread.—W hen the grafts were planted the waxed thread was
intact. When dug in the autumn the grafts showed from 6 to 8 per
cent with knots caused by the pressure exerted by the thread, which
had not rotted away because the wax protected it more or less. The
percentage of smooth trees aside from this was almost the same as for
the plain thread. No perceptible advantage appeared to be gained by
the use of waxed thread as compared with plain thread.

Plain thread with union waxed.— At the time of planting it was noted
that the wax had in many instances penetrated between the surface of
the two pieces. The callus had formed in irregular masses, there being
nothing to confineit. It furthermore appeared as if the wax had exerted
the unfavorable effect already referred to in connection with the use of
waxed paper. When dug the trees in the majority of instances showed
thread knots, due no doubt to the fact that the wax had retarded the
rotting away of the thread. The unions were usually rough. The
unfavorable effect ascribed to the wax was evident not only in the
immediate wound areas, but also all along the bark on both scion and
root pieces, wherever the wax came in contact with the tissue.

Onwrapped grafts.—The grafts with no wrapping showed the excess-
ive development of callus more than any others. However, many of

18270—No. 100—07——2

18 | MISCELLANEOUS PAPERS.

the resulting trees when dug in the autumn showed fairly good unions.
The grafts as a whole fell below the wrapped ones in the number of
smooth trees. There were more deficient trees in this lot, with the
possible exception of those waxed over, owing to defective unions and
failures to form a union. |

EFFECT ON CROWN-GALL FORMATION.

As indicated in the introduction, one of the objects of the experiment
was to determine whether by wrapping grafts it would be possible to
reduce the number of trees affected with crown-gall. In the following
table the total number of trees dug is given; also the kind of wrapping,
and the number and percentage of smooth trees, crown-gall trees, and
hairy-root trees: 3

TABLE I1.—Comparison of smooth trees and trees affected with crown-gall and hairy-root,
resulting when different methods of grafting were used.

Smooth trees. Crown-gall trees. | Hairy-root trees.

se . . Total ! |
_ Kind of wrapping. raraber =
‘| Number.| Percent. Number.| Percent. Number. | Per cent.

|

| {
RUDDER Biss ate eae reas lege e GuD 584 86.5 65 9.6 | 26 3.9
Clothier eee 709 | 604 | 85.1 70 9.8 35 5.1
Warmed paperss=s 2222 meses 671 474 70.6 | 168 25. 0 29 4.4
Rained des sse ase | 645 442 | 68.5 | 130 20.2 | 73 11.3
Waxed threads -22-s-5--2e--4| 675 430 | 63.7 | 182 | 27.0 63 9.3

Plain thread with union | |
WHE Grin een scene aianas | 402 178 44.2 193 48.1 | 31 Ubu
Umivirap pedesee eee e eee | 569 312 a4. 8 200 30. 2 | 57 10.0

} |

A study of this table will show that the wrapping reduced the number
of crown-gall trees very materially, but the results given should be
considered as preliminary and the figures as relative rather than abso-
lute. Only a small number of the trees under test have so far been
dug. The remainder will be dug after one or two years’ growth.

The most effective wrapping, so far as the true crown-gall is con-
cerned, was that made of rubber (86.5 per cent of smooth trees), fol-
lowed closely by cloth (85.1 per cent of smooth trees). The cloth wrap-
ping, however, shows the highest percentage of smooth trees per 100
grafts planted when not only the crown-gall but also the hairy-root
are considered. The difference is very slight, however. The other
wrappings show less favorable results, least of all in the case of the
grafts wrapped with plain thread and covered with grafting wax (44.2
per cent of smooth trees), followed closely by those with no wrapping
whatever (54.8 per cent of smooth trees).

RECOMMENDATIONS.

From the results so far obtained, the use of either cloth or rubber as
material for wrapping apple grafts is recommended. Owing to the
expense involved in the use of rubber, cloth will be found the most
desirable, and in most cases will probably give results fully as satisfac-

100—II

-

WRAPPING APPLE GRAFTS AND ITS RELATION TO CROWN-GALL. 19

tory as rubber. ‘The writers strongly advise against the wrapping of
grafts with thread and subsequently waxing the grafts.

SUGGESTION TO NURSERYMEN.

The results obtained from the experimental plats having shown that
the wrapping has materially reduced the number of crown-gall and other
types of rough trees, it will be very desirable to test these results on a
larger scale. The grafts in these experiments were all made with the
ereatest care, and it would seem probable that the number of smooth
trees obtained was therefore larger than might be the case where com-
mercial grafts are made. The latter are usually not fitted with as much
care, either with respect to size of scion and root pieces or with regard
to an even and close union in the freshly made graft. It is therefore
urged that nurserymen generally test the wrapping of their grafts
this winter, either with rubber or cloth, after the manner previously
described.

Care should be taken in setting out grafts with different kinds of
wrapping to treat them in the same manner, that is—

(1) Use the same variety of scion.

(2) Use the same stock of roots.

(3) Make the grafts at the same time.

(4) Plant the grafts on the same: date. :

(5) Plant in the same field or at least on similar soil.

(6) Cultivate all grafts alike.

Where such tests are made, it is requested that the Bureau of Plant
Industry be informed, so that all the experiments may be compared.

It may prove of interest to estimate the total number of smooth and
rough trees to the acre which would result from the use of various
wrappings, estimating 18,000 grafts to the acre and using as a basis the
percentages of such trees obtained in the tests described in these pages.
By smooth trees are meant trees free from crown-gall and other dis-
eases; by rough trees, trees affected with true crown-gall, hairy-root,
or manifestations of other diseases at or near the point of union. This
estimate has been attempted in the following table, which should be
regarded only as suggestive, however. The results are averaged from
five identical plats in four different States, containing about 9,000 grafts.

TaBLe II1.—Estimate of the number of smooth trees and rough trees which can be raised
on an acre of land by using various methods of grafting.

| Smooth | Rough | Total

WRN Sen trees. trees. | trees.
| | |
Rubber ....-... Sr aT POO ESB ALAA CATO SORORITIES CIO cir aaa eer eee 12, 600 | 1, 980 14, 580
COM GY BO ae a ent or a al Ae he ee | 12, 960 2,340 15, 300
\AVE OG JON OST SE os en herd oatmeal apy yar eR cael ote hn Cue stage 10, 260 4, 320 | 14, 580
Plena Woweenole parse aeseecen oe secon mS CDSG ne oa SORE a OnE mses ae oee | 9, 540 4, 320 | 13, 860
Wee detained dit se -snccis ster icra cris Sa cee ene ok Salon Bie wes ts SALA IR Cte 9, 360 5, 220 | 14, 580
Plainethreadswach uMiOMmawearmxed! ssesene ssnenee cece see cee Ose = aes c eee 3, 780 4, 860 8, 640
LOfLONG RD) OF NG PS eas poche sa Sota ata oO ee eae are eee eres ger TA 6, 660 5, 580 12, 240

100—II

20 MISCELLANEOUS PAPERS.

SUMMARY.

(1) The crown-gall disease of apple trees usually appears at or near
the union of the scion and root piece.

(2) The crown-gall disease may be due to an excessive growth of
callus, or to an infection of fungi, bacteria, or other agencies at or near
the union. |

(3) Protection of the graft at the union will serve to induce a better
union and may also aid in keeping out disturbing factors.

(4) In making grafts care should be taken to use root and scion
pieces of as nearly the same size as possible.

(5) Grafts wrapped with cloth and with rubber yielded 85.1 per cent
and 86.5 per cent of smooth trees, respectively. |

(6) Ordinary thread grafts yielded 68.5 per cent of smooth trees; |
plain thread grafts with the union waxed, 44.2 per cent; grafts with
no wrapping, 54.8 per cent.

(7) It is recommended that apple grafts be wrapped with cloth or
rubber.

100—II

cee Pr — 204:

II—GARLICKY WHEAT.

By J. W. T. Duvet, Assistant in the Seed Laboratory.

INTRODUCTION.

Wild garlic (Allium vineale Li.) was introduced into the United
States from Europe considerably more than a century ago. Since its .
introduction it has made a slow but steady advance, and is now
found growing more or less abundantly throughout the greater part
of West Virginia, Virginia, Maryland, Delaware, Tennessee, North
Carolina, the northern part of South Carolina, the southern part of
Pennsylvania, New Jersey, and Connecticut, and locally in almost
every State east of the Mississippi River. In all places where it has
become well established it is a veritable pest to farmers, millers, grain
dealers, and dairymen.

Wild garlic is one of the worst weeds to eradicate after it has once
gained a foothold, being propagated by underground bulbs, aerial
bulblets, and in some sections by seeds.

WHEAT CONTAINING GARLIC.

The presence of wild garlic in the grain fields of the central eastern
States and in other sections where it is locally abundant has caused a
very great loss to agriculture. Farmers have been obliged to sell their
garlicky wheat at greatly reduced prices, principally because foreign
markets will not buy it except at a low price, and millers as a rule
refuse to handle it, for they have been able to grind garlicky grain only
at a much increased cost. The garlic bulblets gum the rollers, neces-
sitating the stopping of the mills and the washing of the rollers before
the grinding can be resumed. The frequency with which the washing
must be done depends on the quantity of garlic present. In extreme
cases the washing must be repeated every two or three hours, the
operation requiring from ten to fifteen minutes for each set of rollers.

Furthermore, flour made from wheat mixed with garlic bulblets is of
inferior quality, as bread made from such flour has the garlic odor so
disagreeable to most people. This is especially noticeable if the
bread is eaten warm. Moreover, on boards of trade, wheat containing
garlic bulblets in considerable quantity is graded as ‘‘ Rejected,’’ and
is then sold only on sample. Wheat of this character is generally sold

at a price ranging from 20 to 40 per cent lower than No.2 Red. How-
100—111 21

29 MISCELLANEOUS PAPERS.

ever, if the garlic bulblets are present only in comparatively small
quantity (usually less than one-fourth of 1 per cent) it may pass as
No. 2 Red, depending largely on the other foreign substances present
and the amount of water in the grain.

At present there are no available data showi ing dehitere the extent
of the loss due to the presence of garlic in grain; but in wheat alone
this loss is known to be very great. In many sections the growing of
wheat has been almost wholly abandoned as a result of the reduced
price at which garlicky wheat must be sold. An annual loss of
$1,500,000 is undoubtedly a very conservative figure. It has been
estimated by members of the Chamber of Commerce of Baltimore that
60 per cent of the wheat grown in that section of the United States
contains more or less garlic. The three States in which garlic does
the greatest injury to the wheat crop are Maryland, Virginia, and
Tennessee. The average yield of wheat from these three States
during the five years from 1900 to 1904, inclusive, was just short of
29,000,000 bushels. Allowing that 50 per cent of this wheat contains
garlic, we have 14,500,000 bushels of garlicky wheat in these three
States alone. But granting that only one-half of this amount con-
tains garlic in sufficient quantity to throw it out of grade, we still
have 7,250,000 bushels of wheat which must be sold at a greatly
reduced price. A reduction of only 15 cents per bushel means more
than a million dollars annually to the farmers of Maryland, Virginia,
and Tennessee. The members of a prominent firm of grain exporters
in Baltimore state that the depreciation for the Maryland crop alone,
which amounts to about 12,000,000 bushels annually, will be fully 5
to 10 cents per bushel, or an equivalent of $600,000 to $1,200,000. A
large quantity of garlicky wheat, however, does not get into the ele-
vators, being fit only for feeding purposes. Mr. R. L. Wells® states
that, in Tennessee, wheat containing garlic bulblets has been sold as
low as 15 cents per bushel to feed stock.

EXPERIMENTS IN SEPARATING GARLIC FROM WHEAT.

The presence of the aerial bulblets of wild garlic in wheat has always
been objectionable, principally because of the extreme difficulty of
separating them from the wheat. While some of the lighter, imma-
ture bulblets can be blown out by a good fanning mill, the greater
number are of practically the same size and weight as the wheat ker-
nels. Plate I shows wheat kernels and the aerial bulblets of wild gar-
lic of natural size. This similarity in size and shape makes it impos-
sible to separate them during the autumn or early winter by the use of
the ordinary cleaning machinery usually found in the majority of flour
mills and elevators, 1. e., by screening and fanning. If the bulblets

aThe Wild Onion, Bulletin enmceee Agricultural Experiment Station, July, 1895.
100—III ’

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE lI.

WHEAT KERNELS (A) AND THE AERIAL BULBLETS OF WILD GARLIC (B).

(Natural size.)

GARLICKY WHEAT. 23

are allowed to freeze, they afterwards become dry and are then quite
readily blown out, but this is not always practicable.

In view of this fact experiments were undertaken in June, 1905, in
order to ascertain whether the mixture of garlic and wheat could not
be dried artificially, thereby reducing the weight of the bulblets to
such an extent that they could be satisfactorily removed as soon as
the grain is ready for market. The detailed results of these experi-
ments? are given in the following pages.

LOR A:

Lot A consisted of approximately 44 bushels of “rejected’’ wheat
furnished by the Baltimore Chamber of Commerce. When received
it contained 16.55 per cent of water and 2.17 per cent of garlic. The
amount of foreign seed and chaff present was not determined. The
value of this wheat was placed at 65 or 70 cents a bushel.

Expervment No. 1.—A portion of this wheat was dried in the small
grain drier of the Seed Laboratory at a maximum temperature of 136°
F. for two hours. During this time the moisture content of the grain
was reduced from 16.55 per cent to 9.5 per cent, or from 24 to 43 per
cent less than good American wheat normally contains. But this
degree of drying proved insufficient, as 0.28 per cent of garlic still
remained in the sample after a preliminary cleaning. This same lot of
wheat was therefore dried for an additional half-hour and the mois-
ture content was reduced to 8.94 per cent.

Expervment No. 2.—Another portion of seed from Lot A was dried
a few days later for nearly four hours, the maximum temperature
reading 140° F. At the termination of the drying a moisture deter-
mination of a sample of this wheat showed only 5.87 per cent of water.

The wheat from experiments Nos. 1 and 2 was then mixed and
cleaned, and the average percentage of water in the mixed sample was
found to be 7.41 per cent. After cleaning, an analysis of this wheat
showed that the amount of garlic had been reduced from 2.17 to 0.05
per cent, 97.6 per cent of the garlic having been removed. Plate II,
figure 1, shows a l-pound sample of this wheat as received, the
quantity of garlic in 1 pound when received, and the quantity of
garlic remaining in 1 pound after drying and cleaning.

Concerning this lot of wheat the secretary of the Baltimore Cham-
ber of Commerce wrote as follows:

The wheat which you cleaned and returned was the source of a great deal of interesting

comment upon the floor of the chamber, and the general idea is that a very vast change was
accomplished by running it through the drier. The sample sent originally was of such low

aAcknowledgments are due to the members of the Baltimore Chamber of Commerce and
to Mr. Walter Roberts, of Alexandria, Va., and Mr. E. H. Darby, of Seneca, Md., who kindly
supplied the garlicky wheat for these experiments.
100—IIT

24 MISCELLANEOUS PAPERS.

and inferior grade as to prohibit it from going into the elevators, and the drying and cleaning
to which it was subjected made it No. 2 Red, the contract grade, a difference in value of
fully 17 cents per bushel.

An increase of 17 cents per bushel was equivalent to 24.6 per cent
of the value of this wheat before drying and cleaning.

iOME 183.

A second sample of approximately 38 bushels of ‘“‘rejected’’ wheat
furnished by Mr. Walter Roberts, Alexandria, Va., contained 0.56 per
cent of garlic and 15.08 per cent of water and weighed only 57.5 pounds
per bushel.

The lot was divided into three parts for treatment, as follows:

Experiment No. 3.—In this test the drying was continued for three
hours, the temperature of the air varying from 153° to 158° F. and the
temperature of the wheat from 117° to 155° F. The moisture was re-
duced from 15.08 to 7.92 per cent. The weight per bushel was in-
creased from 57.5 to 59.25 pounds on drying and to 60.6 pounds after
cleaning. The quantity of garlic was reduced to 0.05 per cent, the
same as the combined results of experiments Nos. 1 and 2.

Experiment No. 4.—The period of drying in this experiment
extended over three and one-half hours, the temperature of the air
being the same as in experiment No. 3, 153° to 158° F., the tempera-
ture of the wheat gradually increasing from 95° F. at the end of the
first half-hour to145° F. During the three and one-half hours’ drying,
the water content of the wheat was reduced to 6.88 per cent and the
weight per bushel increased to 59.5 pounds. After cleaning, the
weight per bushel was increased to 60.7 pounds and the quantity of
garlic reduced from 0.56 per cent to 0.06 per cent. Plate II, figure 2,
shows a 1-pound sample of this wheat as received, the amount of garlic
in 1 pound when received, and the amount of garlic remaining in 1
pound after drying for three and one-half hours and cleaning.

Experiment No. 5.—The last portion of Lot B was dried for two and
three-fourths hours, the temperature of the wheat reaching 122° F. in
three-quarters of an hour, and 138° F. after one hour, which tempera-
ture was maintained for one-half hour, gradually decreasing during
the last one and one-quarter hours to 117° F., when the experiment
was concluded. The moisture content of the wheat was reduced from
15.08 to 8.48 per cent and the weight per bushel raised from 57.5 to
58.6 pounds. After cleaning, the weight per bushel was 60 pounds
and the garlic present 0.07 per cent.

After drying and cleaning, the wheat from Lot B graded No. 2 Red,
having at that time a value of 85 cents per bushel. As in its original
condition the wheat was purchased for 55 cents per bushel, the drying
and cleaning increased its value 54.5 per cent.

100—I1I

PLATE II.

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture.

FIG. 1.—WHEAT AND GARLIC FROM LoT A

m Lot B.

Fic. 2. —WHEAT AND GARLIC FRO

Fic. 3.—WHEAT AND GARLIC FROM LoT C.

THE QUANTITY OF
THE AMOUNT OF GARLIC

b]

ONE-POUND SAMPLES OF GARLICKY WHEAT AS RECEIVED (A, A, A)

2
4

REMAINING IN ONE-POUND SAMPLES AFTER DRYING AND CLEANING (C, C, C).

GARLIC IN ONE-POUND SAMPLES WHEN RECEIVED (B, B, B)

b o
feb |

GARLICKY WHEAT.
LOT C.

A consignment of approximately 30 bushels of ‘‘rejected’’ wheat,
containing 2.04 per cent of garlic, 16.2 per cent of water, and weigh-
ing only 56.5 pounds a bushel, was lent to the Department of Agricul-
ture by Mr. E. H. Darby, of Seneca, Md.

This lot of wheat was divided into two parts and treated as experi-
ments Nos. 6 and 7.

Experiment No. 6.—This wheat was subjected to an air temperature
of 113° F. for one hour and of 154° F. for two hours, the maximum
temperature of the grain for the last half hour being 149° F. The mois-
ture content was reduced from 16.2 per cent to 8.2 per cent. The
weight per bushel was raised to 57.8 pounds after drying and 60.6
pounds after cleaning, and the amount of garlic was reduced to 0.17
per cent.

Experiment No. 7.—This experiment continued for three hours, as
in experiment No. 6, but the temperature of the air current decreased
gradually from 146° to 122° F., the maximum temperature of the
grain being 131° F. Samples taken at the termination of the experi-
ment showed a moisture content of 8.83 per cent. The weight per
bushel was increased to 57.5 pounds after drying and 60.2 pounds
after cleaning. Plate II, figure 3, shows a 1-pound sample of this
wheat as received, the amount of garlic in 1 pound when received, and
the amount of garlic remaining in 1 pound after drying for three
hours and cleaning. }

A sample of this cleaned wheat was examined by the chief inspector
of the Baltimore Chamber of Commerce.and graded as No. 2 Red, giv-
ing it a value of 84.5 cents per bushel. The highest price offered for
the original lot of wheat was 60 cents per bushel. The removing of
the garlic and the cleaning consequently enhanced the value 40.8 per
cent.

In experiments Nos. 6 and 7 the drying was not continued quite
long enough for the best results, although the quality of the wheat
was raised to ‘‘contract’’ grade. At temperatures from 150° to 158°
F. the drying should continue for two and one-half to three hours, or
until the moisture content of the wheat is reduced to about 8 per cent.

In none of the experiments was it possible to remove all of the garlic,
but im every case the quantity was reduced considerably more than
was necessary to make the wheat grade as No. 2 Red. Moreover, the
quantity of garlic present after the cleaning was not considered suffi-
cient to interfere with the milling of the wheat or to injure the quality
of the flour.

100—1II

26 MISCELLANEOUS PAPERS.

The following diagrammatic figures show the relative quantity of
garlic in the wheat before and after treatment:

Percentages, by weight, of garlic in wheat, Lots A, B, and C, before and after drying and cleaning.

Lor A.
Original sample:
2.17 per cent of garlic.
ST Se SS I FE TT IE ET EEE OT RETESET EEE SEER
Experiments Nos. 1 and 2, combined after drying for 2} and 4 hours, respec-
tively, and cleaning:

0.05 per cent of garlic.
[esa

Lor B.

Original sample:
0.56 per cent of garlic.
2 ae ee eee)

Experiment No. 3, after drying for 3 hours and cleaning:
0.05 per cent of garlic. ;
a

Experiment No. 4, after drying for 34 hours and cleaning:

0.06 per cent of garlic.
ass
Experiment No. 5, after drying for 2? hours and cleaning:
0.07 per cent of garlic.
Bes

Lor C.
Original sample:
2.04 per cent of garlic.
SS ea PE ST PE ES TS POS REE CS OL =) Lene an
Experiment No. 6, after drying for 3 hours and cleaning:

0.16 per cent of garlic.
ae
Experiment No. 7, after drying for 3 hours and cleaning:

0.17 per cent of garlic.
aes

Garlic bulblets as found in wheat contain from 35 to 70 per cent of
water, while the water content of fresh garlicky wheat usually varies
from 15 to 20 percent. During the drying the amount of water in the
wheat is decreased, but at the same time the kernels become more com-
pact and the specific gravity is increased, as is shown by the weight
per bushel before and after drying. On the other hand, the specific
eravity of the garlic bulblets is lowered by the drying. The outer
membranous coverings of the bulblets remain distended and the
shrinkage takes place in the inner portion, thus leaving a small air
space between the bulb proper and the outer protecting layers. This
increased air space, together with the decreased weight due to the loss
of water, makes it possible to separate most of the bulblets from the
wheat by ordinary cleaning machinery.

THE TOTAL COST OF DRYING AND CLEANING GARLICKY WHEAT.

The total cost, including the shrinkage, of drying and cleaning any
given lot of wheat for the removal of garlic depends on four factors:
(1) The amount of garlic removed; (2) the amount of chaff and other

100—IIT

GARLICKY WHEAT. 97

foreign substances, aside from the garlic, removed; (3) the percentage
of water removed from the wheat; (4) the cost of operating the
machinery.

The amount of garlic removed.—In the experiments with the three
lots of wheat herein described practically all of the garlic was removed,
and this must be considered as a loss in weight. The average loss
for each of the three lots of wheat due to the removal of garlic was
2.12 per cent, 0.50 per cent, and 1.88 per cent for Lots A, B, and C,
respectively.

The amount of chaff and other foreign substances, aside from the garlic,
removed.—The loss in weight due to the cleaning, aside from the quan-
tity of garlic, depends entirely upon the amount of light, immature
wheat, chaff, and other foreign substances removed. This loss bears
the same ratio for any lot of wheat. Consequently, strictly speaking,
this additional decrease in weight can not be considered as an extra
expense in the treatment of garlicky wheat. Moreover, the quantity
of foreign substances present has an important bearing on the grading
of the grain. :

The following summary shows the percentages of screenings, includ-
ing the garlic, obtained from the wheat treated as experiments Nos.
a Oe OF al:

Experiment No. 3 gave 611 pounds of clean wheat and 28 pounds,
or 4.4 per cent, of screenings. Experiment No. 4 gave 548.5 pounds
of clean wheat and 15.5 pounds, or 2.8 per cent, of screenings. Exper-
iment No. 5 gave 736.5 pounds of clean wheat and 26.5 pounds, or 3.4
per cent, of screenings. The average percentage of screenings from
experiments Nos. 3, 4, and 5 (Lot B) was 3.54 per cent. Deducting
from this the amount of garlic removed from Lot B, 0.50 per cent,
there is left 3.03 per cent, the proportion of immature wheat, chaff, and
other foreign substances removed.

In experiments Nos. 6 and 7, 1,536 pounds of dried wheat gave 135
pounds of screenings, an equivalent of 8.8 per cent, of which 1.88 per
cent was garlic, leaving 6.92 per cent of immature wheat, chaff, and
other foreign substances removed.

The percentage of water removed from the wheat.—-Garlicky wheat
almost invariably contains a high percentage of water, and the greatest
loss in weight is probably due to the liberation of water during the dry-
ing process. In these experiments the quantity of water was reduced
from 16.55 per cent, 15.08 per cent, and 16.20 per cent to an average
of 7.41 per cent, 7.76 per cent, and 8.52 per cent for Lots A, B, and C,
respectively. In order that the garlic may be removed satisfactorily
it is necessary to reduce the watercontent to approximately 8 per cent,
which is from 4 to 6 per cent less than No. 2 Red wheat normally con-
tains. However, the dried wheat will again absorb water from the
atmosphere, and after the lapse of a few days the water content will be

100—111

28 MISCELLANEOUS PAPERS.

practically the same as that of air-dried wheat. Likewise the clean,
dried wheat can be mixed with any garlic-free lot of wet wheat and the
grade of the latter improved in this way. For this reason, only the
difference between the water content of the wet garlicky wheat and
that of No. 2 Red, which averages about 13 per cent during the first
few months after harvesting, should be considered as actual loss in
weight due to drying. On this basis the loss due to the removal of
water was 3.55 per cent for Lot A, 2.08 per cent for Lot B, and 3.20
per cent for Lot C.

The cost of operating the machinery.—The cost of the actual drying
and cleaning alone is very small. With the low pressure boilers avail-
able for use with the small grain drier in the Bureau of Plant Industry
the maximum temperature possible is only 158° F. At this tempera-
ture it is necessary to continue the drying for from two and one-half to
three hours in order that the weight of the garlic may be sufficiently
reduced so that it can be removed. With the high pressure boilers such
as are found in most grain elevators and flour mills an air temperature
of 170° to 180° F. can be readily maintained, at which temperature the
time factor can be greatly reduced. By careful calculation it is be-
lieved that the actual cost of operating the machinery for the drying
and cleaning should not exceed one-half cent per bushel.

This factor, however, will vary with the capacity of the drier and
the number and size of the other kinds of machinery being operated
simultaneously by the same boilers.

/

THE NET COST OF REMOVING GARLIC.

To ascertain the net cost of removing garlic bulblets from wheat in
order to bring it up to “contract” grade, only the following items need
be taken into consideration: (1) The cost of operating the machinery;
(2) the loss in weight due to the quantity of garlic actually removed,
and (3) the difference in the amount of water normally contained in
good air-dried wheat , which is not farfrom 13 per cent, and the amount
of water in the garlicky wheat before it goes into the drier. On this
basis the cost of drying and cleaning the garlicky wheat discussed in
the foregoing pages was 6.3 per cent, 3.2 per cent, and 5.7 per cent, or
an equivalent of 54 cents, 2? cents, and 44 cents per bushel] for lots
A, B, and C, respectively, as governed by the prices current at that
time. ; :

THE EFFECT OF THE DRYING ON THE MILLING QUALITIES OF
THE GRAIN.

No flour was made from any of the wheat after drying and cleaning;
but the consensus of opinion of the majority of the millers to whom
samples of the dried wheat were submitted was that the milling quali-
ties of the wheat had not been injured by the drying. Such wheat,

100—III

- GARLICKY WHEAT. 29

however, is not fit for milling until it has absorbed water from the
atmosphere, or has been mixed with damp grain, or steamed, in order
to toughen the bran. If the milling is attempted while the wheat
is exceptionally dry, the bran will be easily broken, resulting in the
production of coarse, dark flour.

THE EFFECT OF THE DRYING ON THE VITALITY OF THE WHEAT.

The objection has frequently been made that the high temperature
ordinarily used in the commercial drying of grain will destroy the
germinating power. In the majority of cases the vitality of the grain
after drying is of little importance, as such grain is seldom used for
sowing or planting. The foregoing objections, however, are not well
established, as the vitality of grain is not injured by drying in com-
mercial grain driers at the temperatures commonly employed.

The grounds for the belief that temperatures as high as 140° to 175°
F. for periods of short duration will destroy the vitality of grains are
based on laboratory tests in which no provision was made for tbe cir-
culation of air. Under such conditions the life-giving principles are
readily destroyed, especially when considerable moisture is present.
But when the drying is done in such a way that the moisture liberated
will be readily carried away, as in commercial grain driers, there is
little danger of destroying the vitality of the grains, even though the
duration of drying be several times greater than that given for the
foregoing experiments. —

The following table shows the effect of the drying on the germinat-
ing capacity of the samples of garlicky wheat from lots B and C,
already discussed:

Percentages of germination of wheat from lots B and C before and after drying.

|

| Tempera~- Maximum | Wietor

Dura- | 3 | Cs
Sample mark, | ond | mote | tempers | contene | Germ
| drying. | of wheat.| aaa

| drying. wheat.

Hours. | Degrees F.| Degrees F.| Per cent.) Per cent.
Oricimalssamiples senescence nee Niet Seis etal ea oe Goel le Prenat oe 15.08 8

| 0
IBEX ETTMEMbGNIOR Ses Oe aoe aso Ss eee eee | 3} | 153-158 155 7.92 | 83.5
epee CMiGeINO Asse Oe Se ye Se | 33 153-158 145 6.88 85
RS GOORDIMNGNG NOs Oadacegcssee sol eee ane essee sae | 23 155-108 138 8.48 79.5
Orieimalisamnpol cmp ices sete ais Say sala apieee cee eee nN ee cles ee ei AURIS oe Bele ats | 16. 20 82
SXq EITM eC MibEINIO st OMe a sees See es Ds 113-154 149 | 8.20 83
EXD CRIMECMIGE N One sete. eee ee os Sie tee ee See Se 3 146-122 | 131 | 8.83 85

With but a single exception the percentages of germination were
higher after the drying than before, and such is generally true. In
all cases the germination was low, due to the damaged condition of the
grain when received.. : |

While the tests made are few in number, the results given in the
foregoing table are sufficient to show that a good quality of garlicky
wheat can be dried and afterwards cleaned and used for sowing with
entirely satisfactory results. The garlic bulblets, as found in wheat,

100—III

30 MISCELLANEOUS PAPERS.

contain from 35 to 70 per cent of water. With this high percentage
of water the greater quantity of the bulblets are partially cooked or
scalded during the dryitig process, thus rendering growth impossible.

MACHINERY USED FOR DRYING AND CLEANING.

The drying was done in a small grain drier. In the absence of a
good fanning and screening machine for the larger grains, the wheat
was first run through a fanning mill specially constructed for cleaning
clovers, alfalfa, and timothy. The greater quantity of the garlic was
blown out, but many of the larger bulblets could not be removed in
the absence of screens, and for this reason the wheat, for the final
cleaning, was put through a “‘shaker”’ such as is commonly used for
cleaning rice. *

It is not desired to place any special emphasis on the particular
machinery used for these experiments. Any of the good commercial
driers with any good cleaning m*«*inery should give satisfactory
results.

SUMMARY.

The presence of the aerial bulblets of wild garlic in a large quantity
of the wheat grown in the central eastern United States causes a great
depreciation in its value. The loss to agriculture from this cause
alone is very conservatively estimated at more than $1,500,000 annu-
ally.

The wheat kernels and the garlic bulblets are very similar in size
and weight, which makes their separation by the methods ordinarily
in use next to impossible as long as they are fresh.

If wheat containing garlic is artificially dried, the wheat kernels
increase in specific gravity and the garlic bulblets decrease in specific
gravity, so that practically all of the latter can be removed by good
cleaning machinery.

Garlicky wheat is usually wet, often containing as much as 20 per
cent of water, and the drying should be continued until the moisture
is reduced to approximately 8 per cent.

In estimating the total cost of the treatment of a lot of garlicky
wheat, only the amount of garlic removed, the excess of moisture
above that which good No. 2 Red wheat usually contains, and the
cost. of operating the machinery need be considered. The cost of
removing the chaff, immature wheat, etc., is the same as for the clean-
ing of any sample of wheat free from garlic.

The commercial drying of wheat in a good commercial grain drier
does not injure its vitality, while most of the garlic bulblets are killed,
owing to the higher percentage of water in the latter.

Tt has not been definitely determined, but the more general opinion
is that the drying does not injure the milling qualities of the wheat.

Any of the good commercial grain driers, together with any good
wheat-cleaning machinery, should give satisfactory results.

100—1II1

B. P. I.—212.

IV—METHODS OF TESTING THE BURNING
QUALITY OF CIGAR TOBACCO:

By Wiautman W. Garner, Scientific Assistant, Plant Breeding Investigations.

INTRODUCTION.

As has been pointed out in previous publications of the Bureau of
Plant Industry, a systematic effort is being made to improve the qual-
ity and yield of the tobacco crop by employing the latest and most
approved methods of selection in the old varieties and by creating
and establishing new strains possessing to a marked degree those
characteristics most to be desired in the various classes of tobacco
which the market demands. This work necessitates the careful test-
ing of a large number of types, as well as many individual selections
from each of these types, and for this reason it is very desirable to
have at our command methods capable of showing with certainty even
slight differences in the essential qualities of the various samples to be
examined. It is our purpose to make a careful study of the subject
of testing tobacco from a practical standpoint, as well as the«relation
of the chemical composition of the leaf to its good and bad qualities.

In judging the merits of a cigar tobacco, due regard must be had
for the particular use for which it is intended, since the finished cigar
consists of three distinct components—the filler, the binder, and the
wrapper—each of which must possess certain characteristics. The

«Jn the tobacco breeding experiments conducted by the Plant Breeding Investiga-
tions of the Bureau of Plant Industry, particular attention is being given to the
improvement of cigar tobaccos, including specially high-grade wrapper and filler
types. In connection with these experiments, which are being conducted by Messrs.
A. D. Shamel and W. W. Cobey, of this office, it has been found necessary to com-
pare the characters of a large number of selected individual plants to determine
which ones are superior in their important characters. The means and methods
heretofore used in making such comparative tests were very imperfect,.and one
important preliminary part of the work is to devise special pieces of apparatus which
will enable accurate tests to be made. The devices described by Dr. Garner in the
present paper it is believed will greatly facilitate such testing and add to the accuracy
of the results. The preliminary notes given by Dr. Garner on the influence of
wrapper, binder, and filler on the ‘‘burn”’ of cigars open up an important field of
investigation in connection with the testing and breeding of different types of
tobacco.—HeErBeErt J. WEBBER, Physiologist in Charge of Plant Breeding Investigations.

100—1y 31

Si MISCELLANEOUS PAPERS.

filler must have, above all else, a fine flavor and aroma and a good
‘*burn.” In the case of the wrapper leaf there are a number of
requirements to be met, among which are sufficient elasticity, proper
color, size, and shape, fineness of veins, freedom from objectionable
flavor and taste, a fine ‘‘grain,” and a good burn. Many of these
qualities can be determined by simple inspection, without the use of
any specific tests, while others require special laboratory methods.
The present article has to do only with the practical methods of testing
the burn, deferring to a later day a consideration of the chemical
characteristics of the tobaccos which have been tested.

There are several elements which go to make a good or bad burn,
chief of which are the capacity for holding fire, the evenness of the
burn, the color of the ash and its firmness, the coaling or carboniza-
tion, and the ‘‘ puckering” of the leaf immediately in advance of the
burning zone of the cigar. The final test of any cigar tobacco must,
of course, rest in the smoking of the manufactured cigar, but, while
this gives a direct means of determining the character of the ash, it
does not furnish accurate information as to the evenness of the burn
or the fire-holding capacity of any one of the components of the cigar
except with reference to the other two particular components used in
the experiment. This is particularly true of the wrapper, as was
shown by special experiments carried out to observe the effect of
using different fillers and binders with the same wrapper. The result
of these experiments will be more fully discussed below. Again, it
should be remembered, in this connection, that cigars made by the
same workman and from the same lot of tobacco often vary widely in
their burn owing to the impossibility of avoiding unevenness in the
filler, and this source of error can only be eliminated by several times
repeating the experiment. It is evident, therefore, that, in order to
get reliable data concerning the relative merits of different wrappers
with respect to their burning qualities, the cigar test must be supple-
mented by some other method capable of giving sharp distinctions as to
the fire-holding capacity and evenness of burn.

A method which has long been in use is to ignite the leaf by means
of a lighted cigar or a slow-burning match devised by Nessler,? and
note the number of seconds during which it continues to glow. The
mean of several tests is taken as a measure of the capacity for holding
fire; but the variation in the results obtained, even upon a single leaf,
is so great that little reliance can be placed upon the figures except in
a very general way. In this method no account is taken of the area
of the leaf burned, and the wide differences obtained on a single leaf
are due principally to the fact that frequently the ignited zone soon
ceases to glow except for one or more very small streamers, which

——————

« Landw. Vers. Stat., XI, 399,
100—ry

TESTING THE BURNING. QUALITY OF TOBACCO. 33

continue to burn for a much longer period, thereby giving results
altogether out of proportion to the true burning qualities of the
tobacco in question. Another serious objection to the method is found
in the interference of the veins of the leaf; for it seldom happens
that the glow can cross these veins except around the outer edges of
the leaf, while in the cigar the veins always run longitudinally and
so do not interfere with the burn.

The rational procedure would seem to be to test the burn of the
leaf when wrapped in some such form as is actually found on the cigar,
but without the use of binder or filler. We have devised a method of
this kind in which the leaf, after being properly wrapped and dried, is
burned with the aid of a slow current of air. The current of air com-
pensates in a measure for the absence of the filler and binder, while its
use obviates the unavoidable irregularities of the latter. A detailed
description of the apparatus used and the method of carrying out the
operation will be found on page 37. This test, combined with the
smoking of the cigar, has enabled us to accurately classify a large
number of samples of wrapper leaf with respect to their burning
qualities.

THE SMOKING TEST.

It is evident that no two persons would smoke a cigar in exactly the
same way, nor would the same individual smoke two cigars under
exactly similar conditions. It is necessary, therefore, to use some
means of smoking the cigars artificially in order to eliminate the per-
sonal equation and secure uniformity of conditions. Dr. E. H. Jen-
kins, in the Annual Report of the Connecticut Agricultural Experi-
ment Station for 1892, has described an apparatus for smoking cigars
which was devised by Mr. S. L. Penfield, of Yale University. The
‘* pull” on the cigar is secured by means of an aspirator which is filled
by a continuous inflow of water and emptied at regular intervals by a
siphon. We have modified this apparatus in a number of details in
order to adapt it to our needs, and we give herewith a description of
the form and dimensions which we have finally adopted for use in
our investigations. In this apparatus as many as four cigars may be
smoked simultaneously, while held in such a position that they may
be readily compared throughout the operation.

By reference to the accompanying illustration (fig. 2) it will be seen
that the holders (a, 6, c, and @) for the cigars are so arranged that
they all lie in the same vertical plane, each one 2 inches above and
having its horizontal arm 2 inches shorter than the next lower. A
screen with a white covering is placed immediately in the rear of the
holders to serve as a background, thereby facilitating observation of
the character of the ash. Between the flask bearing the holders and
the aspirator and connected with these by means of ylass tubing is a

18270—No. 100—07——3

34 - MISCELLANEOUS PAPERS.

check valve consisting of a T-tube (¢), the lower arm of which dips
beneath the surface of the water in a suitable vessel (7), thus prevent-
ing a backward draft through the cigars while the aspirator is filling.
The smoke which escapes through this valve has a very disagreeable
odor: hence, it is well to use a bottle fitted with a stopper with two
holes, through one of which passes the lower arm of the T-tube (g),
while through the other passes one end of a long tube (/), which car-
ries away the obnoxious fumes. The aspirator consists of a glass cyl-
sender (7), the upper end of which is fitted with a rubber stopper

Fic. 2.—Apparatus for testing the burning quality of cigars: a, b, c, d, holders for cigars; e, T-tube,
the lower arm of which, g, dips beneath surface of water in/; h, h, tube for leading away tobacco
smoke; 7, aspirator; k, tube leading to water supply; o, p, long and short arms of siphon; J, tube
connecting cigar holders with aspirator; m, tube, with bulb, attached to long arm of siphon; n,
flask carrying the cigar holders.

containing two holes through which pass tubes leading to the water sup-
ply (#) and to the flask carrying the cigar holders (/), respectively.
The lower end of the cylinder is closed with a rubber stopper bearing
the small arm of the siphon (0). The tube furnishing the water sup-
ply is connected with a reservoir provided with a constant-level attach-
ment. To the lower end of the small arm of the siphon is attached a
glass tube (7) bearing a small bulb which materially assists in break-
ing the flow of the water at the moment the aspirator is emptied. The
tubing connecting the parts of the apparatus should not be less than
100—1y

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE Ill,

VARIATION IN BURN OF WRAPPERS DUE TO DIFFERENT FILLERS: A, FILLER GROWN
IN TEXAS FROM CUBAN SEED; B, FILLER GROWN IN OHIO FROM DOMESTIC SEED;
C, FILLER GROWN IN SOUTH CAROLINA FROM CUBAN SEED; D, AN IMPORTED
CUBAN FILLER.

The same sample of Sumatra wrapper was used throughout and the binder was taken from the
same leaf as the wrapper in each case.

TESTING THE BURNING QUALITY OF TOBACCO. 35

6 to8 mm. internal diameter; otherwise the tubes will frequently become
clogged by the condensation products of the smoke. The container
for the cigar holders (7) is filled about two-thirds full with dilute sul-
phuric acid, which serves as an acid wash for the smoke, retaining the
organic bases and thereby further helping to prevent the choking up
of the machine. The lower ends of all the cigar holders should, of
course, extend to exactly the same depth below the surface of the
acid.

In the machine which we now have in operation, the relation between
the short arm of the siphon and the internal diameter of the aspirator
is such that the volume of water delivered at each emptying of the
latter is 600 c.c. This corresponds to an actual capacity of about 450
c.c. for the aspirator, the difference, of course, representing the volume
of water entering the aspirator from the supply pipe while the siphon
isin action. The rate of inflow from the supply tank is approximately
900 c. c. per minute. The internal diameter of the long arm of the
siphon is 8 mm., while that of the short arm is 25 mm. ‘The entire
length of the long arm of the siphon exceeds that of the short arm by
40 cm. An apparatus of the above-mentioned dimensions will smoke
four cigars of the Perfecto type, 4g inches in length, in about thirty
minutes, a rate which is probably somewhat above that of the average
smoker. The pull on the cigar occurs at intervals of thirty seconds
and continues for a period of ten seconds. The frequency of the pull
is controlled by the rate of inflow of the water from the supply tank,
while its duration is governed principally by the relation between the
diameter of the small arm of the siphon and the volume of the
aspirator.

THE EFFECTS OF THE FILLER, THE BINDER, AND THE WRAPPER
ON THE BURN OF THE CIGAR.

As preliminary to the use of the cigar test in examining wrapper
leaf, a series of experiments was carried out to determine the relative
effects of the three components of the cigar on the burn. For this
purpose a number of cigars were made by an expert workman, using
four different types of wrapper on each of four different types of
filler. Ina portion of the cigars the binder used was taken from the
same leaf as the wrapper, while in the remainder a sample of Connecti-
cut Broadleaf tobacco was employed for this purpose. These cigars
were smoked in the above-described apparatus under conditions as
nearly uniform as could be obtained, and the evenness of the burn and
the character of the ash were carefully noted.

With reference to the evenness of the burn, markedly different
results were obtained when wrappers taken from the same sample were
smoked on different types of filler. A typical case of this kind is shown
mm Plate III. The twelve cigars shown were all made from the same

100—Iy

*

36 MISCELLANEOUS PAPERS.

sample of wrapper, and in each case the binder was taken from the
same leaf as the wrapper. In the first group (A), a sample of filler
grown in Texas from Cuban seed was used; in the second group (B), a
heavy filler grown in Ohio from domestic seed; in the third group (C),

a filler grown in South Carolina from Cuban seed; in the fourth group
(D), an imported Cuban filler. The wrapper used on these cigars was
a type of Sumatra tobacco grown in Connecticut and had a very good
burn. The Texas and imported Cuban fillers were known to have an
excellent burn, while the South Carolina filler was markedly inferior
in this respect and the Ohio filler intermediate in burning qualities. It
will be seen that this sample of wrapper burned quite evenly when

used with the imported Cuban and Texas fillers, while with the Ohio
and especially the South Carolina fillers the burn was decidedly uneven.

On the other hand, the effect of using different types of wrapper on
the evenness of burn of any one type of filler was less marked (see Pl.
IV, A, B, and C; also Pi. III, D). The filler used in this experiment
was the imported Cuban, while the wrappers were taken from four dif-
ferent types of Sumatra tobacco grown in Connecticut. Of these four
types of wrappers, that shown in Plate III, group D, had the best burn
and the one shown in Plate IV, group C, the poorest, although little
difference could be seen between the two when smoked on the Cuban
filler. The use of different binders did not cause any marked differ-
ences in the evenness of the burn, as is shown in Plate 1V, groups C
and D. The cigars used in this experiment were all made from the
same wrapper and the same filler, while in group D a sample of Con-
necticut Broadleaf tobacco was used as the binder, and in group C the
binder was taken from the same leaf as the wrapper.

Another important factor in determining the evenness of the burn is
the proper balancing of the component parts of the cigar. It was
found, for example, that a very light’ wrapper will not give good
results on a heavy filler, even though both of these may in themselves
possess a good burn. It will readily be seen that a very thin wrapper
which burns readily and very rapidly will, when placed on a heavy,
slow-burning filler, tend to burn in advance of the latter, and the effect
will generally be an uneven burn. The same result is obtained when
any cigar is smoked very rapidly, for the reason that the oxygen of
the air has freer access to the outer edges of the burning zone and
under the added stimulus it rarely happens that a cigar will burn
evenly. a

As regards the character of the ash, the wrapper and the binder are
relatively of much more significance. It was found, it is true, that
some fillers give an ash lacking in compactness and liable to spht
asunder, but the tendency to flake seems to be controlled almost entirely

«The terms light and heavy as used in this connection refer to the body or thick-
ness of the leaf, which largely controls the rapidity of the burn.
100—1y ° :

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE IV.

VARIATION IN BURN OF FILLERS DUE TO DIFFERENT WRAPPERS AND BINDERS: A, B, C,
THREE DIFFERENT TYPES OF CONNECTICUT-GROWN SUMATRA WRAPPER ON SAME
SAMPLE OF CUBAN FILLER, BINDER BEING SAME AS WRAPPER IN EACH CASE; D, SAME
WRAPPER AND FILLER AS C, BUT CONNECTICUT BROADLEAF USED AS BINDER.

ah

pe

TESTING THE BURNING QUALITY OF TOBACCO. ot

by the character of the wrapper and binder. Furthermore, this lack
of cohesion in the ash of a wrapper may be largely overcome by the
use of a good binder. As to the color of the ash, a binder having a
good burn will impart to the ash of the wrapper a lighter tint and a
more uniform color. The general results of these experiments may
be summarized as follows:

(1) In order to secure a good burn, due consideration should be given
to the proper balancing of the components of the cigar; thatis, a heavy
filler should be wrapped with a comparatively heavy wrapper, while a
light-bodied filler requires a light-bodied wrapper.

(2). Of the three components of the cigar, the filler exerts the strongest
influence on the evenness of the burn.

(3) The influence of the wrapper and binder is shown most strongly
on the character of the ash, and the binder very materially influences
the ash of the wrapper in this respect.

TESTING THE CAPACITY FOR HOLDING FIRE AND THE
EVENNESS OF THE BURN.

The factors of holding fire and of burning evenly are of prime
importance in judging the burn of tobacco, and any sample found
markedly deficient in these points may be rejected without applying
any further test. As has been previously stated, the cld method of
measuring the fire-holding capacity is likely to lead to erroneous con-
clusions, while there has heretofore been no direct method of deter-
mining the evenness of the burn of wrapper leaf. In the process
which-we have used for testing wrapper tobacco with regard to these
elements of the burn, the area of the leaf consumed, rather than the
time elapsing before the glow is extinguished, is measured.

The form of the apparatus used in this method will be understood
by reference to the accompanying illustration (fig. 3). The essential
feature is the form on which the leaf is wrapped, consisting of a col-
lapsible wooden tube, one end of which fits into a glass tube of the
same diameter. ‘This latter is in turn connected with a second glass
tube through which is drawn a current of air. The best material for
making the wooden form is well-seasoned cherry with a straight grain,
but ash has also been found to answer the purpose very well. From the
wood selected is made a cylinder 5 inches in length, ? inch in diameter
at one end, and tapering slightly to the other end (see fig. 4). In the
larger end of the cylinder a 2-inch hole is bored to a depth of 32 inches,
and the shell thus formed is separated into six equal segments by saw-
ing to a depth of 33 inches. The smaller end is cut down for a dis-
tance of 1% inches, so as to fit snugly into the glasstube. The shoulder
_ thus formed should correspond in depth to the thickness of the wall of
the glass tube. Near the larger end of the form a groove (ce) is cut,

into which is fitted a rubber band. The plug (d@) has a diameter such
100—IV

38

that when inserted in the end of the form the latter is expanded to its

MISCELLANEOUS PAPERS.

original size. The receiver (a) for the form is made by drawing out

Ve Hy

Ij er |
Ha SS
H WH

Fic. 3.—Apparatus for testing the burning quality of wrapper tobacco: a, entrance of air current; b,
wrapper to be tested; ¢, c, glass tube to which the form bearing the wrapper is attached by means
of the cork, m; d, d, large glass tube fitted with corks, n, n, through which passes ¢, c¢; f, flask
containing water; 0, small glass tube dipping beneath the surface of the water in f; p, Short glass
tube leading from f; h, pump by means of which the current of air is secured; e, e and g, g, rubber
tubing connecting parts of apparatus; ft, water tap; 7, outflow of water.

one end of a short piece of thick-walled glasstubing. All of the above
dimensions are based on tubing having an internal diameter ‘of 14 mm.
(9/16 inch) and an external diameter of 18 mm. (11/16 inch). The

small end of the re-
ceiver is fitted with
a soft cork (6), by
means of which it is
connected with the
other portion of the
apparatus.

From the leaf to
be tested, which
should be quite
damp, the wrapper
is cut into a form
quite similar to that
used for cigars, and

Fic. 4.—Construction of form on which leaf is wrapped for use in
apparatus shown in figure 8: a, glass tube for receiving the form; ),
cork by which receiver (a) is connected with remainder ofapparatus
shown in figure 3; ¢, rubber band for collapsing the form; d, plug
for expanding the form; e, form on which leaf is wrapped.

the same rules are observed as regards the cutting of right-handed and
left-handed wrappers, etc. Beginning at the outer end the wrapper is

100—IV

.
—-- ee e e

TESTING THE BURNING QUALITY OF TOBACCO. — 39

rolled quite tightly, first on the form and then on the glass. At the
beginning of the process of rolling, the extreme outer ccrner of the
base of the wrapper is attached to the overlapping portion with a bit
of cigar paste, and at the end of the operation the tip of the wrapper
is attached to the receiver by the same means. A number of samples
to be tested are thus wrapped on the forms and set aside until they
have dried out properly. The plug in the end of the form is then
withdrawn and the rubber band causes the walls of the latter to col-
lapse, so that it can be easily withdrawn from the receiver. This
leaves the sample of wrapper securely attached to the glass tube,
and in exactly the same form it would have on a cigar. The tube
carrying the sample to be tested is connected with the remainder of
the apparatus, shown in figure ©, the construction of which will be
understood without further explanation. The current of air is fur-
nished by means of an ordinary filter pump, and its rate can be con-
trolled with sufficient accuracy by measuring the flow of water through
the pump. The end of the wrapper is ignited with a flat gas flame,
and the evenness of the burn and the portion consumed before it ceases
to glow are carefully noted. Our method of recording the results is
to grade each sample on a scale of ten, both with reference to the
evenness of the burn and the fire-holding capacity. Of course, stand-
ards in these tests are purely arbitrary, as the results are only intended
to be comparative. Under the conditions laid down for the expert-
ment, wrappers having markedly good burning qualities will burn up
completely and evenly with only one lighting, and these are given a
grade of 10. 3

For the purpose of comparing the results obtained by this method
with those given by the cigar test with reference to the evenness of the
burn, a number of leaves were selected from different types of wrap-
per tobacco. One half of each leaf was used fcr wrapping a cigar and
the second half was wrapped on the form for testing, as has just been
described. There was a decided lack of agreement in the results
obtained by the two methods when only one type of filler was used in
making the cigars. It was found that frequently a wrapper that
graded only 5 or 6 on a scale of 10 in what may be called the ‘* form
test ” would burn quite evenly on the cigar, whereas another wrapper
grading as high as 9 in this test would show an uneven burn on the
cigar. <A good illustration of this pomt is found in a wrapper which
was scored 10, 9, 10, respectively, in three experiments with the form
test and gave a fire-holding capacity of 65 seconds by the old method
of Nessler. On one type of filler this wrapper gave a very uneven
burn, but when smoked ona lighter filler the burn was perfectly satis-
factory. These results, then, seem to emphasize the fact that, although
the final judgment as to the burning qualities of a wrapper which has
shown up well in the preliminary tests must be based on the smoking.

100—IVv

40 , MISCELLANEOUS PAPERS.

of the cigar, great care must be exercised to avoid the sources of error
in this test which have been previously discussed. The test should not
only be repeated with a single type of filler to avoid the effects of any
possible unevenness or other imperfections in the manufacture of the
cigars, but at least two different types of filler should be used, one of
these being heavy and the other light in the sense in which these terms
are used here.

TESTING THE BURN OF CIGAR-FILLER TOBACCO.

Testing the burn of a filler is a much simpler problem than is the
case with a wrapper. The principal elements of the burn are the
evenness and the capacity for holding fire, and the character of the ash
is unimportant, except that it should be compact. The evenness of
the burn and the fire-holding capacity are best determined by using
the cigar test. In the case of filler tobacco the capacity for holding
fire thus refers simply to the length of time the cigar will continue to
burn after being lghted without being puffed by the smoker. The
effects of the binder and wrapper on the burn may be avoided by
making the entire cigar from the filler leaf to be tested. Another
decided advantage in making the whole cigar from the same tobacco
is that the aroma, which is so important in the filler, can also be tested
at the same time. In determining the fire-holding capacity it is only
necessary to light the cigar and test it at gradually increasing intervals
of time to find whether it has ceased to burn. It is, however, desir-
able to test the fire-holding capacity and the evenness of the burn on
separate cigars if sufficient material is at hand for this purpose.

100—1v

B. P. I.—229.

V.—THE DRUG KNOWN AS PINKROOT.

By W. W. SrockBerGER, Expert, Drug-Plant Investigations.

INTRODUCTION.

The drug known as pinkroot is derived from the underground por-
tions of Spigelia marilandica L. (P1.V), an American herb now found
growing most abundantly in the Southern States and occurring locally
in the Mississippi Valley and eastward. It came into use in America
as a vermifuge about 1723 and because of its valuable properties soon
came to occupy an important place in materia medica. Unfortunately,
_ however, conflicting reports on its physiological effects in time estab-
lished for pinkroot a reputation for uncertain action, and within the
last fifty years the use of this drug, once regarded as highly reliable
and valuable, has greatly decreased. Since it has seldom been held at
high prices the cost has not operated to drive it out of the markets.

The cause of the apparent loss of high efficiency formerly claimed
for pinkroot has engaged the attention of students of crude drugs for
many years. The demonstration by Dr. R. H. True“ that an unsus-
pected substitute had crept into the markets and to a considerable
degree replaced the true article has explained in large measure the
unfavorable commercial and medical status of pinkroot. The results
here outlined of a detailed study of pinkroot and its more important
adulterants may serve to aid collectors in discerning the real pinkroot
and to assist drug experts in distinguishing the plant from its sophis-
tications in its commercial form.

TRADE VARIETIES OF PINKROOT.

The complex nature of the material put upon the market as pink-
root has long been known to the drug trade, and although the real
nature of the spurious article was not understood, its presence was
recognized, and various sorts of pinkroot came to be distinguished by
definite trade names—e. g., true pinkroot, genuine pinkroot, south-
ern pinkroot, Georgia pinkroot, Kast Tennessee pinkroot, western
pinkroot, and true fiber pinkroot. The visible differences by which
these trade varieties are segregated may be utilized in distinguishing

« Pharmaceutical Review, 21: 364, 1903.

100—v 41

49 MISCELLANEOUS PAPERS.

the true from the false pinkroot, as it is now definitely known that
certain of the trade varieties are wholly composed of worthless sub-
stitutes. |

In many cases careless or unscrupulous collectors and dealers have
not regarded the distinguishing features of the various sorts of pink-
root, or have been ignorant of them, with the result that very general
confusion exists as to the character of the real drug and its adulter-
ants. The authors of some prominent publications on crude drugs
have evidently based their observations on trade varieties of pinkroot,
as they have illustrated and described one of the most important adulter-
ants as true pinkroot. 3

IDENTITY OF CHIEF SUBSTITUTES.

East Tennessee pinkroot (2velia ciliosa Pursh), a member of the
plant family Acanthaceae, is the most important adulterant. Observa-
tions on the plant structures present in commercial samples of pinkroot
convinced Dr. R. H. True, in 1900, that the chief part of this crude
drug consisted of a substitute instead of Spigelia and that this substi-
tute was a species of Ruellia. In trying to get plants of pinkroot for
cultivation, Doctor True, in 1903, purchased several hundred roots
from a dealer in eastern Tennessee. These roots were set out in the
testing gardens of the Bureau of Plant Industry at Washington, D. C.,
and the plants kept under close observation. On developing they
were found to differ markedly from Spigelia, and upon flowering were
identified as Ftwellia ciliosa (Pl. V1), a plant which had never appeared
in the list of suspected adulterants prior to this time.

The examination of the microscopic structure of this plant recalled
at once the figures in some text-books purporting to represent Spige-
lia and those illustrating an article by Greenish in the Pharmaceutical
Journal, 1891, on the structure of Phlox carolina, a plant which had
long been regarded as an extensive substitute for pinkroot. It was
evident that a double confusion existed with regard to Ruellia. On
the one hand it was so widely mistaken for Spigelia that its peculiar
structures have been regarded as diagnostic of pinkroot, and on the
other it was recognized as a substitute, but wrongly regarded as Phlox,
a plant lacking many of the striking characteristics of Ruellia.

In order to satisfactorily determine the relation of these substitu-
tions to the true pinkroot, observations have for three years been
made upon plants of Spigelia, Ruellia, and Phlox under cultivation at
Washington, D. C., and fresh material secured from them has been
used in making a comparative study of their structure. The results
of this study do not support the view that Phlox is an adulterant of
pinkroot, and, moreover, several samples of a substitution supposed
to be Phlox have proved, upon examination, to be composed entirely

of Ruellia. It is only through long and familiar observation in the
100—v

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE V.

PINKROOT (SPIGELIA MARILANDICA ES:

ca oe
Sy ae
ee

Pay
a
Nii

bal ‘alee
Sala Foca: Ml
pai at

THE DRUG KNOWN AS PINKROOT. 43

living condition of all species here concerned that it has been practi-
cable to uncover fully the true relations involved in the drug called
pinkroot.

MINOR ADULTERANTS.

Aside from Ruellia,the adulterants of Spigelia may be regarded as
impurities, due in the main either to the carelessness of the collector
in not sorting out the roots with which the plant was associated in its
growth, or perhaps to a lack of familiarity with the plant on the part
of young or inexperienced collectors. With Spigelia other roots
sometimes occur which have a greater market value than the true
pinkreot, and therefore can not be regarded as intentional adulterants.
The worthless roots frequently present, however, may have been
introduced by the collector with full knowledge that a fraud was being
perpetrated. In commercial samples of pinkroot, among other impuri-
ties have been observed roots of golden seal (Hydrastis canadensis L.),
serpentaria (Aristolochia serpentaria L.), soapwort (Saponaria offici-
nalis L.), wild yam (Doscorea villosa L.), and stoneroot (Collinsonia
canadensis M.).

METHODS OF DISTINGUISHING PINKROOT FROM ITS SUBSTI-
TUTES.

Once familiar with the true pinkroot it is hard to see how any drug
collector could confuse it with the plants so frequently substituted in
its place. Spigelia and Ruellia grow over large areas, largely over-
lapping and in much the same habitat, and have on the whole a cer-
tain general resemblance; but they should be readily distinguished by
observing any one of their several striking characteristics.

In Ruellia (PI. V1) the flowers are borne scatteringly along the stem
in the axils of the leaves; in Spigelia (Pl. V) they are aggregated at
the top of the plant in a one-sided spike. In Ruellia the pale magenta-
colored corolla forms a slender tube below, expanded upward into a
broad, flaring limb. The anthers and style are not protruded. In
Spigelia the corolla forms a rather broad tube, narrowest at the throat,
prolonged upward into spreading, narrow, triangular portions. The
exterior is brilliant cardinal in color, bright yellow on the inside; the
style and anthers are exserted. The leaves of Ruellia are bright green,
usually short-petioled or sessile, frequently more or less hairy. In
Spigelia they are dark green, glossy, and sessile.

In the crude drug the forms are separated by less evident gross
characters. Ruellia, however, has a coarser, harsher root system than
Spigelia, and the roots show a tendency to lose the cortical tissues.
leaving the naked, woody cylinder exposed. ‘The roots of Spigelia are.
delicate, fibrous, and usually very numerous. When dry they break
and crumble very readily.

100—y

a4

MISCELLANEOUS PAPERS.

The differences in structure between Spigelia and its substitutions as
seen under the microscope are usually very marked. This is especially
true of Ruellia, the only important adulterant found with Spigelia,
since the other plant parts sometimes present are usually recognized

by their gross characters.

A comparison of figures 5 and 6 will show
the most important differences in minute
structure. The numerous cystoliths present
in Ruellia as a very conspicuous feature are
wholly lacking in Spigelia and Phlox ovata.
The large sclereids of the root of Ruellia are
not found in the other two plants, and starch,
which is present
in Spigelia, is

absent in both

: Ruelliaand Phlox.

SOPNADO: In the powdered

sy | CLS form Ruellia al-

= ee, 26 Y ways reveals its
i) & y @ 5 eee presence by the
Oe) numerous’ stone

Bea cells and cysto-

liths, which usual-

e ly remain intact

Fig. 5. Cross section of the root of
Spigelia marilandica L.: a, ep-
idermis; b, cortex; d, xylem;
e, cambium; 7, pith; 7, endo-

dermis; 7, perieycle. x 180.

even in finely pow-

By a 3 dered material.

= GeO ee @ Powdered samples

); Sn SA rea of the under:

7 Ao Noegeanset tiie & ground portions of
ee es the Phlox at hand
= Kc gaye no reaction

for starch. The

fineness of the

starch grain of
Spigelia and its
lack of striking:
characters render
uncertain its iden-
tification among

Fig. 6. Cross section of the root
of Ruellia ciliosa Pursh: a,
epidermis; 6, cortex; c, bast
fibers; d, xylem; 7, endoder-
mis; 7, pericycle; m, cystoliths;
n, collenchyma; o, sclereids.
x 150.

many other plant starches which might be readily introduced in the

powdered drug.

The starch grains of Spigelia measure about 4 /,

and in powdered pinkroot are associated with parenchyma cells and

long light-colored scleren

chyma fibers. The absence of starch from a

powder supposedly made of pinkroot suggests at once that the material

is not Spigelia. On the

other hand, the presence of starch, while

indicative of Spigelia, is by no means conclusive proof of its presence.

. 100—y

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE VI.

EAST TENNESSEE PINKROOT (RUELLIA CILIOSA PURSH).

eo

B. P. 1.—230.

VI—ORCHARD GRASS’

By R. A. Oaktey, Assistant Agriculturist, Harm Management Investigations.

INTRODUCTION.

Orchard grass (Dactylis glomerata I.) is a well-known standard
grass which is grown to some extent in every State in the Union and
quite commonly in the region east of the Mississippi River and north
of the northern portions of Alabama and Georgia. It attains most
importance, however, in Kentucky, southern Indiana, Tennessee,
North Carolina, Virginia, West Virginia, and Maryland, and seems
quite thoroughly adapted to a variety of soils in these States.

It may be said that the general opinion of farmers in regard to the
value of orchard grass either for hay or pasture is quite unfavorable.
This unfavorable opinion, which is due somewhat to prejudice, exists
to a greater extent in the timothy region than elsewhere, and as the
limits of this region are reached and crossed orchard grass is much
more highly regarded. The objectionable features of the grass are in
general its bunchy habit, coarseness, and the unpalatability of its hay
unless cut at the proper state of maturity. These objectionable
features are not alone the cause of its unpopularity or the reason why
it is not grown more generally. There is no doubt that orchard grass
could be grown very successfully throughout the greater portion of
the timothy region, but as the demand for any hay except timothy is
very limited farmers see little inducement for them to raise it. On

2 In connection with the general plan of the Farm Management work it is contem-
plated to take up the study of various seed crops. Much interest is now being mani-
fested in better seeds for the farmer. This is especially true of forage-crop seeds,
including both grasses and clovers. Mr. Oakley’s paper, which is contributed from
the Office of Farm Management, conducted under tbe direction of Prof. W. J. Spill-
man, is a valuable contribution to the methods followed in growing orchard grass

for hay, for pasture, and for seed. Special attention is called to the fact that orchard

grass seed as usually grown is for all practical purposes pure. The investigations of
this Bureau have shown that considerable quantities of the seed of this grass found
in the market contain seed of other and less desirable, cheaper grasses. That the
seeds of these cheaper forms have 2en added for the purpose of adulteration seems
evident from the fact that the grass bearing them are not found in orchard grass
fields to any extent worth mentii .1g.—B. T. Gauioway, Chief of the Bureau of
Plant Industry.
100—y1 45

46 MISCELLANEOUS PAPERS.

account of its maturing well with a number of other very valuable
grasses and clovers its popularity may in time increase as the advan-
tages of such mixtures become more generally appreciated.

Orchard grass is exceedingly variable and offers a large field for
selection and breeding. Its variable characters of most importance
are its coarseness, bunchiness, and time of maturing. By consistent
selection with special reference to the first two characters valuable
strains may in time be developed which will not possess the objection-
able features of the common orchard grass now being grown.

METHODS OF CULTURE.
SEEDING.

While there are some methods that are generally employed in the
culture of orchard grass, still there is a great difference of opinion
even among the most successful growers in any one locality as to the
best practices. In the seed-producing section of Kentucky and Indi-
ana it is the common custom to sow the grass in February on fall
wheat at the rate of from three pecks to one bushel to the acre... Since
the crop in this section is almost entirely harvested for seed, it is not
considered desirable to sow more than a bushel. In years past as
much as two bushels to the acre were sown, but it is now the gen-
eral opinion that one bushel is sufficient, and even less is often
used. A bushel of orchard grass seed weighs 14 pounds. Orchard
grass to give large yields of seed should be reasonably thin, as
it produces more abundantly when in this condition. It is usually
‘sown broadcast, as it does not feed out well through a press drill,
either by hand or with a wheelbarrow or other type of seeder, and is
covered very shallow. Good results are often obtained by not cover-
ing the seed, and it is quite a common opinion that too deep covering
is the cause of many of the failures to secure a stand.

A method of seeding which is often followed in the section men-
tioned is to scatter the orchard grass straw from which the seed has
been thrashed on ground that has been sown to wheat. This is usually
done in February. The straw acts asa mulch in this case and the seed
needs no covering. It is very essential that it bescattered evenly and
very thin; otherwise the stand will be too thick and unsatisfactory.
The greatest objection to this practice is that unless the straw is very
clean the meadow is sure to be weedy, and some are of the opin-
ion that since the seed that is left in the straw or blown over with it
is mostly of poor quality a field of inferior and unequally maturing
grass will be the result.

Orchard grass may be sown successfully after corn by splitting the
rows with a disk harrow as soon as the crop is removed. This may
be done any time during the month of October, and in February or as

100—y1

se

ORCHARD GRASS. AY

soon as the weather is favorable the grass may be sown with a broad-
cast seeder at the ordinary rate, and the ground being uneven at this
time the freezing and thawing which follow will cover the seed suffi-
ciently. Disking seems to give much better results than plowing,
since the ground if plowed will not have time to thoroughly settle
before the time of seeding. Rolling would doubtless be beneficial
after seeding in this manner. ;

In western Virginia and in Tennessee orchard grass is commonly
sown the latter part of September or the first of October with wheat
on the ground at the rate of a bushel and a half to two bushels to the
acre, the wheat being drilled in at the rate of three to five pecks to the
acre and the grass sown either broadcast by hand, with a broadcast
seeder, or an attachment to the drill, and covered as shallow as possible.

Orchard grass is often sown with oats, usually in March, on ground
that has been previously in wheat and which has been plowed the pre-
ceding autumn. A half seeding of oats is usually sown in this case,
and gives as a result only a fair crop. The grass, however, makes
more pasture the first season as arule than when sown with a full
seeding of either wheat or oats. Early fall seeding with winter oats
in sections where the latter can be grown may be depended upon to
give good results, but on account of the Hessian fly it is not possible
to sow it with wheat much before October.

A crop of hay is not expected the first season, whether the grass is
sown in the fall or spring, either alone or witha nurse crop. If sown
alone a light cutting may be secured, provided the conditions are
favorable, in the latter part of August or September; but in general
the grass is pastured and not cut except at the time when the grain
which is sown with it is harvested. The following season it makes a
crop of either hay or seed, as is desired. There may be some advan-
tage in sowing the grass alone for the extra quantity of forage pro-
duced the first year, but whether this and any other advantages that
may come from seeding in this way will compensate for the profit
accruing from the nurse crop is an undecided question.

MIXTURES WITH RED CLOVER.

Throughout almost the entire region where orchard grass is grown
it is quite a common practice to sow red clover with it. This practice
is a good one, not only for the value of the red clover in maintaining
the soil fertility, but also for the fact that its presence greatly improves
the orchard grass either for hay or pasture. In the seed-producing
sections red clovei is a menace to the seed crop, especially the first and
second years. As it is impossible to cut the orchard grass above the
clover, the leaves and heads get mixed in with the seed and are difficult .
to separate from it. Although the presence of the leaves in the

100—y1

48 MISCELLANEOUS PAPERS.

orchard grass seed materially decreases its commercial value, the
advantage of having the clover in the field more than compensates for
this. | ;

In sections where the grass is grown for hay and pasture, red clover
is sown at the rate of one bushel to 5 or 7 acres, usually as early in
the spring as the weather will permit. It is, however, sometimes sown
in the autumn at the same time as the orchard grass, but the seed of
the two are not mixed, as they do not feed evenly through the drill or
seeder. In cases where clover is sown in the spring on orchard grass
that has been sown the fall before, it is either covered lightly by means
of a drag harrow or left uncovered. Less clover is sown to the acre
in seed-producing sections than where the grass is intended for hay or
pasture, the customary quantity being one bushel to 8 or 10 acres.
In these sections the first crop is frequently cut for hay on account of
its containing so much clover. The second crop usually contains very
much less and is cut for seed, as are also the following crops, since
the clover at the end of two years usually disappears. Pasturing the
field appears to materially increase the longevity of the clover, and it
is not uncommon to see meadows that are 6 or 7 years old containing
~almost as much clover as they did the first year.

Much trouble is now being experienced in securing a catch of red
clover throughout the greater part of the region where it is grown.
Asa result alsike is being substituted in some sections, and where it
has been tried thoroughly it is giving good results. This difficulty in
growing red clover will doubtless soon become a serious proposition,
especially in seed-producing sections, and unless alsike or some similar
leguminous crop can be grown it will be only a few years until more
barnyard manure or commercial fertilizer will have to be used. At
the present time there is very little commercial fertilizer applied to
orchard grass, although it is the opinion of some of the more success-
ful growers that an application of about 200 pounds of good fertilizer
in the spring, just as the grass begins to grow, would yield profitable
results.

MIXTURES WITH OTHER GRASSES.

On account of the bunchy tendency of orchard grass it is often
desirable to mix it with other grasses for hay or pasture, and while
this has not been practiced as yet to any great extent the results
obtained from such mixtures are very promising. Aside from affect-
ing the palatability of the grass, the mixtures have a tendency to
increase the yield. Orchard grass matures well with tall meadow oat-
grass and meadow fescue, and in some localities in Tennessee a mix-
ture of it with the latter is attracting considerable attention, especially
‘for pasture. Doubtless in time orchard grass will be more generally
grown for hay and pasture in mixtures with these or other grasses.

100—vV1 :

ORCHARD GRASS. 49
LIFE OF MEADOWS.

Orchard grass is a more hardy and permanent grass than timothy,
and asa result remains productive in a meadow under most conditions
much longer. In the principal sections where it is grown the average
life of a meadow is from five to seven years, although it is a question
whether it might not be broken up profitably at the end of four years.
Throughout almost its entire region Kentucky bluegrass is its natural
enemy and works in around the bunches almost to its ultimate exclu-
sion. Redtop and Canada bluegrass also are present in many sections
with the Kentucky bluegrass, and at the end of five or six years these
three grasses are greatly in the majority. Pasturing seems to facili-
tate the growth of the bluegrass, inasmuch as it has a tendency to
cause the orchard grass to become more bunchy, and it is also a means
of spreading the bluegrass seed. During the last year of its existence
it is customary to pasture the orchard grass field, and late in the
autumn or early in the winter it is broken up and is planted to corn
the following spring. It is well to have the field broken up as early as
possible so as to give the sod time to rot sufficiently before planting
the corn.

USES AND VALUE.

HAY.

According to chemical analysis orchard grass hay should be equal,
if not superior, to timothy, but in real practice it does not seem to be
able to successfully compete with the latter. In large cities there is
practically no demand for any hay except timothy, and the demand for
orchard grass hay is only local and very limited. In the timothy
region orchard grass is looked upon very unfavorably, but where
timothy can not be grown so successfully its hay is used to a erie
extent and is considered of very good quality.

As previously stated, orchard grass should be sown thicker when
desired for hay than for seed, 2 bushels of good seed to the acre
being usually required, for aniltes thick it becomes coarse and woody.
Its value as hay is increased by the addition of red clover or alsike,
and where it has been sown with other grasses, such as tall meadow
oat-grass or meadow fescue, its quality seems to be improved by such
mixtures. The state of maturity at which the grass makes the best
hay is when it is just in bloom. Not only does the quality seem to be
better at this time, but the yield is also at the maximum.

In some sections it is considered a good hay for horses, but it is of
more value for cattle, and especially for fattening them for the market.
As a feed for sheep it is of only fair quality. The value of the hay
depends not only on the state of maturity at which it is cut, but also
on the bunchiness and coarseness of the grass. These characteristics
$ 18270—No. 100—07——4

50 MISCELLANEOUS PAPERS.

are influenced largely by the method of culture, and it is often for the
reason that farmers do not thoroughly understand growing it that they
condemn it as a hay grass. Seeding evenly with the proper quantity
of seed and careful pasturing are important factors in securing a
good meadow.

PASTURE.

For pasture, orchard grass gives best results in mixtures with other
grasses and clovers, and is of special importance from the fact that it
can be grazed early and late in the season. It is quite a valuable grass
if for no other reason than this. It also stands grazing fairly well.
It must, however, be closely pastured; otherwise it will become too
coarse and woody, and stock will not eat it. Stock do not relish the
mature grass, and invariably lose flesh when turned on a field in this
condition. To secure best results from pastures, they should be mowed
some time during June to keep down the weeds, and again later as
needed. In this way they are kept clean and more productive. Blue-
grass and white clover are usually very prominent in most orchard
grass pastures and are valuable additions, as they grow between the
bunches of the orchard grass, thus increasing the yield. The white
clover is also of value in maintaining soil fertility.

SEED.

Orchard grass seed 1s produced to some extent throughout the entire
region in which it is grown. ‘There is quite a quantity raised in west-
ern Virginia, but the greatest seed-producing area is in the vicinity of
Louisville, including Jefferson, Oldham, and Shelby counties, Ky.,
Clark County, Ind., and some of the counties adjoining those
in both States mentioned. Just why there is more seed _ pro-
duced in this section than elsewhere is not definitely known. Some
are of the opinion that it is because orchard grass seeds more
readily there, which may be true. However, the cultural methods
employed by farmers in this section may have something to do with
the success attained in raising it. In Oldham County, Ky., the
average production is about 55,000 bushels, which represents prac-
tically 5,000 acres, as the yield is about 10 to 12 bushels to the acre.
The growing of seed in the section referred to_is a profitable industry,
and there are many farmers who engage in it quite extensively with
uniform success. It is said to be a more profitable crop than wheat,
and when the harvest of the two conflict orchard grass is given the
most attention. The average price of seed for the last ten years has
been about $1.25 a bushel. The seed alone does not represent the
entire return from the field, for after it is harvested the meadows
afford hay or pasture, or both, from which a considerable profit
accrues. Orchard grass seed is the controlling crop in this section,
and the cropping system is planned to accommodate it.

100—v1

Bu). 100, Bureau of Plant Industry, U. S. Dept. of Agriculture. PLATE VII.

FIG. 1.—HARVESTING ORCHARD GRASS FOR SEED.

Fic. 2.—METHOD OF SHOCKING ORCHARD GRASS; SHOCKS SHOWING BANDS AT Top.

ORCHARD GRASS. 5

“HARVESTING THE SEED CROP.

The methods used in harvesting orchard grass seed are practically
the same throughout the whole country. In general, harvest begins
about June 15 and lasts about ten days, though when there is a large
acreage it is often necessary to begin earlier than this, in order to finish
before the seed becomes too ripe. An inferior quality results from
cutting the seed before it is sufficiently mature, and this seed is quite
readily detected by its light-green color. When properly matured
the seed is straw colored, and not at all green. A common test to
determine whether the seed is at the proper stage for cutting is to
beat the heads in the palm of the hand, and if quite a quantity shat-
ters off it is considered ready to cut. To one unfamiliar with the crop
it would seem that the waste from shattering would be great.

Orchard grass is harvested with an ordinary grain binder (PI. VII,
fig. 1), making as small bundles as possible, in order that they may
cure readily. The bundles are placed usually three in a shock and
the shocks tied at the top with two bands of straw, one about 8 inches
below the other (PI. VII, fig. 2). They are bound in this way so as to
make them more stable and to prevent the seed from shattering. The
shocks are made small to facilitate handling at the time of thrashing,
and so that they may be easily tied at the top with the straw bands.
They are left standing from two to four weeks, or until they have had
time to cure thoroughly, and are thrashed without stacking. On an
average it takes about 5 pounds of twine for 100 bushels of seed. The
crop is of such importance that the fence corners and other places that
can not be reached with the binder are cut with the cradle and bound
into bundles by hand.

When the grass is sufficiently tall it is cut from 12 to 14 inches high,
to avoid the low-growing weeds, such as. plantain and sorrel, and also
clover and bluegrass. Another advantage in high cutting is that it
leaves more of the undergrowth to be utilized later for hay or pasture.

THRASHING.

The common grain separator is used for thrashing with the ordi-
nary cylinder and concaves, but with special riddles and with nearly
all the wind shut off to prevent too much of the seed from being blown
over. In hauling the shocks to the machine, racks with tight beds or
with tarpaulins spread over the bottom are used to catch the seed that
shatters off, which is usually considerable. This is always heavy seed,
and is worth saving. Since the shocks are small, a whole one may be
thrown on the rack at one forkful without breaking the bands. This
reduces shattering to a minimum. Unless the grass is very weedy
the thrashing machine cleans the seed sufficiently for the market, but
most of the larger growers have hand fanning mills, which are used.
when necessary. Seeds like those of redtop are easily blown out, but

160—v:

52 MISCELLANEOUS PAPERS.

it is harder to dispose of the bluegrass and some of the weed seeds,
such as plantain and whitetop. From the machine the seed is put into
8-bushel bags for shipping. . Thrashing costs on an average 8 cents
per bushel, with the customary crew furnished.

HANDLING THE AFTERGROWTH.

In cases where orchard grass is cut for seed there is a great differ-
ence of opinion as to how the aftergrowth should be handled. It is
generally considered that pasturing is not in the least detrimental but
is even beneficial. Whether the aftergrowth should be cut for hay
is an undecided question. It is a common practice, however, to cut
it, due to the fact that it is depended upon largely for hay, since tim-
othy and other hay grasses are not grown to any great extent. After
the grass is cut for seed, especially when it is cut sufficiently high,
there is always considerable green undergrowth. This continues to
grow, and during the latter part of August or about the first of Sep-
tember is at the proper stage to cut for hay. If there is clover pres-
ent in the aftergrowth it makes a very fair quality of hay and yields
from one-half to one ton to the acre. The quality of this hay is not
so good as that of the hay made from the first cutting.

While it is a general practice to cut the aftermath during the latter
' part of August or September, there are some who prefer to cut it as
soon as the shocks are removed from the field, as it is believed to be
better for the following seed crop if it is cut then. It is the opinion
of some that the aftermath should be cut in any event, and consequently
if it is not desired for hay it is cut and left on the ground. Others:
are of the opinion that if it is cut at all it materially injures the next
year’s crop, especially so if used for hay, as the two cuttings remove
a large amount of plant food from the soil without much return.

Judicious pasturing, to say the least, is not detrimental to the field,
and in all probability is more or less beneficial. The aftergrowth,
which comes on after the seed crop is removed, furnishes grazing
until it is covered with snow, and in the more southern sections where
the grass is grown lasts nearly the entire winter. Sheep can be very
profitably pastured on this aftergrowth, and in many cases almost as
much money is made from the pasture that it affords the sheep as
from the seed crop, on account of the length of time which it will
furnish grazing. At present prices sheep are equally as profitable as
cattle, if not more so, and can be pastured on orchard grass to much
better advantage.

VALUE OF THE STRAW.

There is much difference of opinion regarding the value as a feed
for stock of orchard grass straw from which the seed has been thrashed.
Some state that it is of almost as much value as the hay, but in general
it is thought to be about equal to wheat straw. Its value depends

100—v1

ORCHARD GRASS. 58

largely on three factors: The state of maturity at the time of cutting;
the amount of aftergrowth, including red clover, contained in it, and
the success with which it is cured. If the grass is cut before the seed
is sufficiently mature to harvest, the straw will be of more value for
feed than when it is cut at the proper stage. The undergrowth which
is present probably furnishes as much feed as the straw itself, if not
more, especially when it contains clover.

It is a common practice to cut the grass as high as possible to avoid
the weeds and clover, but if it is short there is necessarily a great deal
of undergrowth cut with it. If the grass has not received too much
rain while in the shock and is stacked properly or put into a barn or
shed at the time of thrashing, the straw will be of much more value
than if carelessly handled. In general, there is little attention paid to
the stacking of the straw, and it is commonly left in piles just as they
are made by the machine. When utilized for forage it is fed to horses
or cattle, usually the latter, but is of very little value for sheep.
Aside from its value as a feed, straw may be used for seeding meadows,
as previously described. It should never be used for this purpose,
however, unless thoroughly free from weeds.

WEEDS IN ORCHARD GRASS SEED FIELDS.

The weeds which are most troublesome in orchard grass fields, espe-
cially in sections where seed is produced, are whitetop (Arigeron
annuus), red sorrel (Jtumex acetosella), oxeye daisy (Chrysanthemum
leucanthemum), milfoil (Achillea millefolium), and the plantains
(Plantago lanceolata and P. aristata). Most growers pay much atten-
tion to keeping these weeds out of their fields and go to considerable
expense for labor to mow them or cut them out with a hoe just before
harvest. A method which is now quite commonly used and which is
most effective and practicable is to pasture the fields with sheep. This
is an excellent practice and it is comparatively easy to distinguish at
harvest time between fields that have been pastured in this way and
those that have not’ by the absence of weeds in the former. Such
good results have been obtained by pasturing sheep on the grass to
keep down the weeds that farmers are raising more sheep than formerly
and are growing cleaner seed. It is acommon practice to turn the
sheep on in the spring as soon as the grass begins to grow and allow
them to remain until the early part of May. As the grass advances
toward maturity the sheep eat very little of it, but graze mostly upon
the weeds and undergrowth, and especially on the whitetop, which is
one of the worst weeds present, if not the worst. They do little dam-
_age to the field when it is dry,and in wet weather they are kept off, as
they drag down too much of the grass. Although it is the custom to
turn the sheep out of the fields in the early part of May, some of the
most successful growers leave them in until nearly harvest time. Itis

100—v1

54 MISCELLANEOUS PAPERS.

not uncommon to see sheep in fields that are ready to harvest. (When
it is possible to do so the fields should be pastured late, as this prac-
tice is more effective in keeping down the weeds, since it takes them
but a short time to make sufficient growth to interfere with the clean-
ing of the seed. Cattle are sometimes pastured on fields that are
intended for seed, but they tramp down too much of the grass and are
not as satisfactory for this purpose as sheep.

OTHER GRASSES IN FIELDS INTENDED FOR SEED.

Much has recently been said regarding the presence of seeds of other
grasses in orchard grass seed. Those which appear to be the most
common are meadow fescue (/estuca pratensis) and the rye-grasses
(Lolium perenne and Lolium ctalicum). The seed of these grasses is
much heavier, but it resembles orchard grass seed to such an extent
that its presence is not readily detected. Meadow fescue and rye-grass
have very much the same appearance, but there is no difficulty in dis-
tinguishing them from orchard grass, as their seed habits and general
habits of growth are different. If these grasses were present in con-
siderable quantities in the orchard grass fields in Kentucky, Indiana,
and western Virginia, where practically our entire supply of seed is
produced, the presence of their seed in orchard grass seed could be
readily accounted for. The orchard grass fields in these sections, how-
ever, are almost entirely free from other grasses, and only in a very
few cases are there any others present, with the exception of some
Kentucky bluegrass (Poa pratensis) and Canada bluegrass (70a com-
pressa) and a little cheat (Bromus secalinus) and redtop (Agrostis alba).
Bluegrass and redtop, especially the former, come in naturally in the
older fields, and cheat is present practically only the first year, due
to its having been in the wheat which just preceded the grass crop.
The quantity of meadow fescue and rye-grasses in-these fields is insig-
nificant, and there are only a very few cases where these grasses are
present at all. The total percentage of other grasses in orchard grass
throughout the whole seed-producing section is sosmall as to be hardly
worthy of consideration, and statements made to the effect that the
presence of their seed in orchard grass seed is due to the fact that they
are grown with the orchard grass and can not be separated from it are
entirely without foundation. Farmers in general are extremely care-
ful to keep their orchard grass fields free from other grasses, for the
reason that their seeds are readily detected by buyers and as a conse-
quence the seed invariably sells at a lower price. It is a comparatively
easy matter for seed growers to have pure seed for their own sowing,
and there would be absolutely no advantage to them in growing
meadow fescue, rye-grasses, and other grasses with orchard grass.

100—v1 : |

I

f

ORCHARD GRASS. 55

SUMMARY.

Orchard grass is of considerable value for early and late pasture,
and in the southern part of the region where it is grown can be pas-
tured nearly the entire year. When used for pasture, bluegrass and
white clover are commonly grown with it.

Orchard grass hay is of value, especially when it contains red clover,
and can be fed to horses successfully. It is a good forage for cattle
that are being fattened for market.

When grown for seed, orchard grass is a profitable crop, as it yields
on an average 10 to 12 bushels to the acre and sells for $1.25 a bushel.
Aside from securing a crop of seed, the aftergrowth may be either
pastured or cut for hay. This aftergrowth makes a very fair quality
of hay, and when cut during the latter part of August or September
gives a yield of from one-half to one ton to the acre.

Although not previously stated, orchard grass is quite valuable for
binding soils, and on rough land that washes badly it can be used for
this purpose effectively.

Orchard grass may be seeded either in the autumn or spring with
about equally good results. Spring seeding, however, seems to be the
mostcommon practice. In most cases it is sown broadcast on fall wheat
on fields that have been in wheat the previous year. One bushel of
seed is a sufficient quantity when the grass is to be grown for seed.
When grown for hay or pasture, more than this should be used. A
good catch may be obtained by scattering the straw evenly and thinly
on fall wheat in early spring.

Red clover can be profitably sown with orchard grass at the rate of
1 bushel to 5 or 7 acres. Mixtures of orchard grass with other
grasses, especially with tall meadow oat-grass and meadow fescue, are
giving good results for-hay and pasture in places where they are being
tried.

The average life of an orchard grass meadow is from five to seven
years, after which it is plowed up, usually late in the fall, and put into
corn.

Orchard grass is harvested for seed from about June 15 to June 25.
It is cut with an ordinary grain binder and bound into small bundles,
requiring about 5 pounds of twine to 100 bushels of seed. The
bundles are put three in a shock and bound at the top with a band of

grass to make them more stable and to prevent the seed from shatter-
ing. Thrashing is done from the shock after the grass has stood in
the field from two to four weeks, with an ordinary separator, using
special riddles.

100—v1

56 MISCELLANEOUS PAPERS.

Sheep are pastured on orchard grass in the spring to keep down the
weeds. They are sometimes allowed to remain in the field until nearly

time to harvest. This practice is very effective in keeping clean the’

fields that are grown for seed.

The percentage of meadow fescue, rye-grasses, and other grasses in
orchard grass fields that are grown for seed is so small as not to be
worthy of consideration.

100—VvI

——— eee

B. P. I.—228.

Wile tteebereer Or UGEPER UPON WATER
BACTERIA“

By Karu F. KeiuermMan, Physiologist in Charge of Soil Bacteriology and Water
Purification Investigations, and T. D. Beckwitrn, Scientific Assistant.

INTRODUCTION.

Of the many methods of chemical! treatment for water purification,
the copper method has recently received the most attention. The use
of this metal, or its salts, was urged primarily’ for the eradication or
control of polluting algz, though popular attention has been directed
more particularly to the various results obtained in destroying the
typhoid bacillus. |

The discrepancies between laboratory results of some of the investi-
gators of this phase of the subject have deterred many engineers and
sanitarians from conducting important tests of the value of copper
under emergency or epidemic conditions. These discrepancies are
perhaps in some cases due to reasons which are taken up later in this
bulletin, and in some cases to the lack of comprehension of the essen-
tial difference between treatment of drinking water which contains
relatively little albuminoid matter’ and treatment of bouillons or
emulsions.@

« The copper method for controlling algal pollution can no longer be considered
in an experimental stage. The accumulation of results of treatments constantly made
under the direct supervision of officials of the Department of Agriculture and the
numerous results reported to this Department by independent experimenters render
further discussion of this question superfluous. The caution should be reiterated,
however, that no rule for determining the amount of copper sulfate to be added can
be given, and each body of water must be treated in the light of its special condi-
tions. This caution is eminently applicable to copper treatment of a water supply
for bactericidal purposes, and, as Mr. Kellerman and Mr. Beckwith have shown in
their recent work, the problem of using dilute solutions of copper for destroying
Bacillus coli and Bacillus typhi in water is a rather complicated one. Pertinent con-
ditions must be understood thoroughly before an application of copper can be safely
advised, and whether an emergency treatment of an unfiltered and contaminated
water, or a continuous treatment of a filtered water supply, or a treatment of a sewage
effluent is contemplated the work should be supervised by an expert.—A. F. Woops,
Pathologist and Physiologist, Acting Chief of Bureau.

b Buls. 64 and 76, Bureau of Plant Industry, U. S. Dept. of Agriculture.

¢ See also Buls. 64 and 76, Bureau of Plant Industry, U. 8. Dept. of Agriculture.

d A ease in point is a paper by Dr. J. B. Thomas, Report on the Action of Various
Substances on Pure Cultures of the Amceba Dysenteriz. (Amer. Jour. Med.
Sci., vol. 131, No. 1, Jan., 1906, p. 116.) ‘‘ Uniform suspensions of the amceba were
made by pouring 4 cc. of distilled sterile water over the surface of a 48-hour slant
agar culture of the amceba and cholera spirillum, scraping off the surface growth
and mixing with the matter by means of a platinum wire, and pouring the resultant
emulsion into a sterile test tube; 4 cc. of the antiseptic solution (in double strength)

100—viII 57

58 MISCELLANEOUS PAPERS.

In spite of the fact that the field results of several experimenters
have apparently established the point that copper sulfate will not
destroy ordinary water bacteria at concentrations fatal to the colon
and typhoid bacilli, the somewhat fanciful objection has been sug-
gested to chemical treatment of any kind, and to copper treatment in
particular, that bacteria desirable for oxidation of organic matter and
other beneficial changes in a water supply might be injured equally
with the typhoid bacteria, and thus a treated water be more poten-
tially dangerous than an untreated water known to contain typhoid
organisms; in other words, that many bacteria which could be of
decided benefit in a slightly polluted water supply might be eradicated
by copper treatment and that in this way the fractional sterilization of
a reservoir by copper might pave the way for a more dangerous con-
tamination.

Investigations of these and other points have been undertaken, and
it is believed that valuable data have been obtained, applicable to
copper treatment for alge, to emergency treatment for typhoid, and
to copper treatment in connection with filtration. The copper treat-
ment of sewage may be influenced by the same conditions that bear
upon the effect of copper treatment of water. For the present, how-
ever, the investigations of Johnson,’ at the Columbus, Ohio, sewage
testing station may be considered sufficiently accurate for practical
purposes.

to be tested was then added to the 4 cc. emulsion of amcebee, thus making a fairly
uniform emulsion of 8 cc. of liquid to one 48-hour slant culture, the mixture con-
taining a definite amount of the chemical to be tested. * * * It would appear
from the above results that it would be disastrous to rely on the action of copper
containers to purify water infected with amcebe or cholera.”’

«Caird. Copper Sulphate Results. Paper read at meeting of American Water
Works Association, Boston, Mass., July 10-14, 1906. ;

Jackson. Journal New England Water Works Association, vol. 19, 1905, pp.
563-568.

Hollis. Journal New England Water Works Association, vol. 19, 1905, pp..571-572.

Stokes and Thomas. The Effect of Copper Sulphate upon the Bacteriological and
Chemical Constituents of Large Bodies of Water. Public Health Papers and Reports,
American Public Health Association, vol. 31, part 1, 1905, pp. 75-90.

The Copper Treatment of Sewage Effluents. Report on Sewage Purification at
Columbus, Ohio, 1905.

‘‘Available data indicate that the removal by either process of applied pathogenic
and nonpathogenic bacteria is in fairly direct proportion, generally speaking,
although, of course, saprophytic bacteria may multiply within the tanks or filters, so
as to obscure the true removal. Under some conditions it might be advantageous to
employ a germicide, such as sulphate of copper, as a final treatment for sewage efflu-
ents of doubtful bacterial purity.’’ (P. 471.)

‘‘Independent of the question of complete sterilization as touched upon * * *
it may be that there is a field of usefulness in some places for copper sulphate or other
germicidal chemical in the treatment of coarse-grain filter effluents, in order to bring
them from a bacterial or hygienic standpoint to a degree of purity strictly compar-
able with that of the effluent of ordinary intermittent sand filters.’ (P. 479.)

100—vII

EFFECT OF COPPER UPON WATER BACTERIA. 59

RESISTANCE OF VARIOUS BACTERIA.

Several species of bacteria occurring commonly in Potomac River
water have been isolated, and comparative tests have been carried on
with these bacteria and with the colon bacillus. An examination of
the tables showing the exact results of these tests indicates clearly
that no danger to most of the common saprophytic bacteria can be
expected from using concentrations of copper sufliciently strong to
destroy Bacillus coli. To allow as little variation as possible in the
different tests all experiments were carried out in triple-distilled water.
This will probably explain the sensitiveness of most of the bacteria to
copper solutions, for, as Gildersleeve” has stated, ‘* The resistance of
bacteria washed in distilled water is lessened, due in all probability to
the fact that some of the slimy substance which surrounds the bac-
terial cell and protects it to some extent from the action of detrimental
agencies Is removed.” For purposes of comparison the table showing
the action of copper sulfate on various bacteria in tap water, pub--
lished by Gildersleeve,’ is reproduced below.

Average} Percentage destroyed in hours specified.
number
tothe eu- | |
Organism. Dilution. | bic cen- | | | | | | | |
timeter | 02 7)2:-| 3.) 4. 5. 6. lo -|\Bee e he NAILS aes at
in | | | | | |
control. eee | |
(eee 250.0008) 11050001008} 82 |- 222 \s6 vac |anne|e eens eee ESE ests asia eters | Sa
He tge SHOE OOONIe LOMO: 1999: OOM ke a5|-euee ai | ree eee Ne c/o Pris eee ie Sere |
B: typhosus..---- Eee OOO COW ITO) COs ete WO esa alleaana||Gooclssacaslooeealesos|isaase Resesesesl eaealine cre |
1:1, 500, 000 | 120,000 | 50) 85 | 99 |100 |....|..-.- focoeellecanllesodclooee
LEZ OVOROOOM IS OSOOON eases Do) SOs B827 Sie S72 93n) 98.5 LOO) erst arcs ee
1: 250, C00 | 105,000 |100 |....|..-- Fae Sea lease ae lssece ess eee [eeodiooss) Seede
OOO NOOO S at 205000 TODS MOON ereeer |eeayarcts|| r= otal rsrsire es crctell ersterallSerere ieee |Senslleacse
B.colicommunis |? 1:1,000,000 | 99,000 | 80 | 99 100 |..... epeeleaoae ec Reet aN Feil bat sel hea Mere
1:1, 500, 000 | 150,000 | 87 | 95 | 99 |100 |....}..-.. [seater fiers ora oer ats faeter Geseliceeea| Gace
1:2, 000, 000 | 110,000 | 8 | 10 | 14 | 27 | 50} 8 | 90 | 92 | 93 | 93} 95 | 98 | 100
(eS PA) C00) 4) IL OO) a Ss BUD) oS cocalloodellossec eel ee eliae as sea ledogloncca|incac
|| 1: 500,000 ; 120,000 | 40 | 95 | 97 |100 eal ieee aes | aease eco are (oaea eee occ
Badysenienrics =| 121 000000:|, 725000") 39) 50) |) 62>) 8d) 1-99 995 100) |e nt Se jean once Tee
|} 1:1, 500,000 | 12,400 | 20 ! 80 | 40! 42 60170 | 75°! 81 | 8 | 87} 90! 91 100
|{ 1:2, 000,000 | 18,600 | 20 | 20 | 25 | 30 | 30} 45 | 60 | 62 | 62 (oto i a a) 98
Helier 2007000 a 9210001 | SOR OOs MOOR We ive | sre [areca =m eal tarrnmarerela | ei | eee ee [Pee
TS FOOL COO S| SOOO) |) Ges | SO) SO) MOOS eesalicocscllacnacllosca lasso) |Sécclloacalinnaa- ear
Be closer. ss2- 1:1, 000,000 | 101,000 | 33 | 85 | 89 | 96 | 96 | 99 |100 |....|.....]...-|. BS ee: eee
|} 1:1,500,000 | 89,000 | 5 | 10} 30) 40 | 70 | 8 SI) |) Sid) hy SE) WD): ees Reese
1{ 1:2,000,000 | 94,500; 3 | 10} 31] 40 | 80] 88 | 8 | 88} 91 | 91 | 93 | 97 100
| 1: 250,000 | 115,000 | 93 ae me ar iiel ee oallossoe| book laSacd|loeos lege eaamanseate
= || 1: 500,000 | 106,000 | 65 2. | HW) Sacorcenss|laccocllososlisenas|looss fievepeeni maisstall re se
B. proteus vul- |) 4:1 000,000 | 111,000 | 28 | 51 | 82 90 | 95| 98 |100 |....|....|. eee es ee
Seats i - | 1:1, 500,000 | 99,000 | 10 | 18 | 27 | 42 | 69 | 90 | 93 | 98 | 99+/100 |....\..... <4
| 1:2, 000, 000 | 118,000 | 0 | 12 | 22 | 36 | 51 | 65 78 | 80 | 85 | 88 | 92 | 95 | 100
IS = PAKO), COO) PO. CLLO) 1) sy 1S) 9) OSE) ceed lsascullsccelsadecl|scocleoa- levsrcrets Keres
|| 1: 500, 000 | 109,900 | 15 | 26 | 80 | 95 | 97 | 99 | 99+/100 }.....]...- isonslicocce Sfes
B. prodigiosus...|% 1:1,000,000 | 110,000 | 9 | 11 | 16 | 33 | 33 | 45 | 47 | 61 | 63 | 69}..-..|..... 93
= HH et 500; 000 || 107, 000" || ~4:)' 12 4 17 | 3 38 | 46 | 46 | 48 | 51 52 | 60 | 61 92
1:2,000,000 | 98,000 | O 1 fe}. |} ts} TIO) ae 15 | 30 | 388 | 41 | 43 | 50 88
1: 250, 000 92E 000) /R99e 100) eae s (eee HESS eoaeers eer losdallecosaliscdalloond|ocace sae
Staphylococcus |} 1: 500,000 | 88,000 | 50 | 70 | 90 100 Hoi leessiS =| tetera) pote losecallscos Werererel | ereverans
pyogenes au- |, 1:1,000,000 |} 86,000 | 15 | 30 | 30 | 70 | 78 | 85 | 97 | 99 | 99 |100]....|.....
REUSE teers |} 1:1,500,000 | 100,000 | 8 | 22 | 28 | 96 58 | 69 Sor} 939/95 | 99FLOOn Re ees lees
'{ 1:2, 000, 000 95, 000 1 87} 10 | 80 | 50 | 64 79 | 82 | 85 | 98 | 99 | 99-+-| 100

@Studies-on the Bactericidal Action of Copper on Organisms in Water. American
Journal of Medical Science, vol. 129, 1905, p. 754.

OOp. cit., p. 759.
100—viI

60 MISCELLANEOUS PAPERS.

The figures in this table are rather surprising in connection with
the statement that ‘* very little difference was found between distilled
and filtered water used in the laboratory.” The similarity here of the
action of copper in distilled and filtered tap water, contrasted with the
marked difference in the action of distilled and filtered tap water in
Washington, emphasizes a point previously mentioned,¢ that the water
itself deserves as carefula study as do the organisms contained therein.
This is suggested again in Phelps’s? report showing that with either
hard or turbid waters the germicidal efficiency of metallic copper is
much lessened. Again, in view of the high toxicity that investigators
have reported. with copper in Philadelphia tap water, it seems neces-
sary to assume that this water either is peculiarly favorable to main-
taining the metal in a toxic state, or, what seems equally probable,
for rendering the bacteria unusually sensitive.

The results of our own experiments are given in the following tables.
‘All the experiments, unless otherwise indicated, were conducted in
Weber resistance glass test tubes, each containing 10 c. c. of water
triple distilled from glass, portions of which had been treated pre-
viously with the desired amount of copper sulfate. All tubes were
inoculated with a 2 mm. loop of the proper organism. The temper-
ature during each experiment varied from 18° to 22° C.

TABLE I.—Effect of copper sulfate upon Bacillus mycoides.

1 part copper sulfate to—

Durationol exposure toaction | check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
OU SOP EER Se 8 parts of | parts of | parts of | parts of | parts of | parts of
water. water. water. | water. water. water.
| Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
QO OU TS teehee bees en 105 | 90 590 | 310 70 250 90
GY OUT Se ae ee pp ee ree 80 | 1 20 80 15 35 15
DAI OUTS Sane ee eee oe eee 185 | 10 130 | 110 | 40 20 50
- | 1
TABLE I1.—Effect of copper sulfate upon Bacillus megatherium.
1 part copper sulfate to—
| | —— Seas
ees ° See Tae action | Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
PRene : parts of | parts of | parts of | parts of | parts of | parts of
| water. water. water. water. water. water.
| | >
| Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
OsnOUTA a feast ee eee eee 70 | 5D 45 ‘ 90 15 50
MAGUS Coie ee ok ee cena eh rae | 50 | 10 | 25 30 40 0 20
GeO UES a eee ae eee 40 | 15 | 20 10 40 ibs 15
DA Wouiss © sss setae See ance ae | 200 | 10 15 5 10 2 | 10
|

« Bul. 76, Bureau of Plant Industry, U. S. Dept. of Agriculture, p. 12; and Keller-

man, Journal New England Water Works Association, vol. 19, 1905, p. 536.

> Journal New England Water Works Association, vol. 19, 1905, pp. 537-639.

100—vII

EFFECT OF COPPER UPON WATER BACTERIA.

TasiE II1.—Effect of copper sulfate upon Bacillus mesentericus.

61

1 part copper sulfate to—
Duron os ca pOsUre te action) Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
EA EOD DOSNT AS _ parts of | parts of | parts of | partsof parts of | parts of
water. water. water. water. water. water.
Colonies. Colonies. | Colonies. | Colonies. | Colonies. Colonies. | Colonies.
O) XG Tir pees 5 Se oe ee rs ere 300 380 400 520 280 440 | 470
DEN OURS Eee eo eee 280 170 310 440 | 260 340 | 360
GR OUESs eSa sate ees 430 | 10 290 320 250 310 | 390
ZAG UES Sha oa = See oe ek Se 1, 350 0 0 530 3} 4 | 30
TaBLE 1V.—Effect of copper sulfate upon Bacillus mesentericus fuscus.
1 part copper sulfate to—
Duration of exposute toaction| check. | 10,000 | 25,000 | 50,000_| 100,000 | 500,000 | 1,000,000
PP one parts of parts of | parts of | parts of | parts of | parts of
water. water. | water. water. water. water.
| |
Colonies. | Colonies. Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
QBN O Utes ee see pean eee 30 | 25 | 25 50 20 30
PROUT S Seta oere eee ee 07 5 | 50 | 10 3 | 0 i
GEN OUTS see esc see aise 2 | af 30 | 5 5 2 1
7211 VOD Rotana y= SR GORE SSE 70 | 110 70 | 45 0 | 220) 80
| |
TaBLE V.—ELifect of copper sulfate upon Streptococcus pyogenes.
| | 1 part copper sulfate to—
Duration ob exposure to action! check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
PP ; | parts of | parts of | parts of | parts of | parts of | parts of
| water. water. water. | water. | water. water.
Colonies. Colonies. } Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
OSH OUT Eee a ee eee ee 180 879 875 300 250 90 | 180
DIN OUTS: ee a Nee ee 210 0 0. 290 180 180 180
Ga OUTS Sh osse aes eee 140 0 Olas 280 | 230 | 240 160
PAR OUIS= Sans es aoe ae 35 0 0 | 390 | 150 | 10 | 20
TaBLE VI.—Effect of copper sulfate upon Bacillus subtilis.
1 part copper sulfate to—
Bee eetS action | Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
P : parts of | parts of | parts of | parts of | parts of | parts of
water. water. water. water. | water. water.
| | | |
: Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
ENO Us eee ae ee Se 310 80 20 | 130 85 100 30
PM OUESH IS ee oe = 220 1 3 | 30 120 | 70 10
BOVIS SS en ee 330 a 1 25 85 50 2
PAE OUIS eee ee ee 2, 800 1 0 30 70 | 65 0
TaBLE VII.—Effect of copper sulfate upon Bacillus prodigiosus.
1 part copper sulfate to—
Duration of exposure toaction | Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
PP : | parts of | parts of | parts of | parts of | parts of | parts of
water. | water. water. water. water. water.
| Colonies. | Colonies. | Colonies. | Colonies. Colonies. | Colonies. | Colonies.
Oph Oimr pes eee = Se ee eee | 350 450 400 | 1, 050 22,000 2, 000 1, 800
PRN OUTS wee ee ee ees 750 65 180 | 1,700 1, 350 2, 050 1,550
Bonie eo ok oe | 1,250 | 4 0 2 | 0 550 200
PART OUNGES Peete ek ke eee | 925 | 0 0 0 | 0 0 0
\

100—viI

62

MISCELLANEOUS PAPERS.

TaBLE VIII.—Effect of copper sulfate upon Bacillus liquifaciens phosphorescens.

|

Duration of exposure to action.

1 part copper sulfate to—

0 -

Check. 10,000 25,000 50,000 100,000 500,000 | 1,000,000
ESCO DES SULTS. parts of | partsof | parts of | parts of | parts of | parts of
water. water. water. water. water. water.
| | :
Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. Colonies.
Ocho UAT Sere ee eel 16, 500 3,400 | 2,400 16, 000 4,500 10, 400 13, 000
Zhou wee eee e nent eee eee eee a ey : i. 4 8 | 2, 900 7,300
OUTS252 5 on eee eee 23, | 640 7, 000
oahours-t ease ee 36, 000 0 0) 0 0 60 5, 300
TaBLeE 1X.—Effect of copper sulfate upon pink yeast.
| 1 part copper sulfate to—
Duration of exposure toaction | creck. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
LAD | parts | parts parts parts | parts parts
|of water. of water. of water. | of water. of water. | of water.
| | i |
| Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
pour Bia ceases oo een Saree 310 550 100 | 110 ~ 100 | 220 108
OUTS ete os ree ee 150 | 5 | ik 0 i 65 85
Biigurseiee cre ae E 70 0 0 0 1 | 3 50
DA OUES Manatee ae ease | 90 0 | 0 0 | 0 | 1 30
|
TABLE X.—Effect of copper. sulfate upon Bacillus coli.
1 part copper sulfate to—
Duration of exposure to action Check. 100,000. 500,000. | 1,000,000 | 2,000,000 | 3,000,000 | 4,000,000
pects : parts of parts of | parts of | parts of | parts of | parts of
water. water. | water. water. water. water.
|
Colonies. Colonies. Colonies. | Colonies. | Colonies. Colonies. | Colonies.
Oe OWT ees We ree tenes as 2, 690 2,300 3,100 | 2, 700 2, 250 1, 800 1,770
QAO UTS eee eo eee 2,350 1, 650 2,690 | 2,000 | 1, 650 | 1, 850 1, 850
Gfhours ese sae ae eee aoe 2, 300 | 0 0 95 | 210 | 850 | 1,070
DAN OULSS hee Soe = ems eee 6, 300 0) 0 0: 0 | 0} 65
TaBLeE X1.—Effect of copper sulfate upon sulfur yellow bacillus.
1 part copper sulfate to—
Duration of exposure toaction | Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1,000,000
PRES : | parts of | parts of | parts of | parts of | parts of | parts of
water. | water. | water. water. water. | water.
| Colonies. | Colonies. | Colonies. Colonies. | Colonies. | Colonies. Colonies.
Q8h OUT ees os eee eee 2. 800 | 40 3, 100 | 2, 800 4, 100 860 | 1,300
DE OUES aoe he he go eee | 2, 000 | 0° 0 0 280 a 2
GSHOUTS ia ere ae ee eee | 1,500 | 07 0 0 | 0 0 |
DAG OUTS es oe oe eee 24,000 | 0 | 0 | 0 0 0 | 0
| |
| |

TaBLe XII.—Eifect of copper sulfate upon Pseudomonas radicicola (soy).

Duration of exposure to action | Check.

1 part copper sulfate to—

; | 10,000 25,000
of copper sulfate. | "parts of | parts of

| water. | water.
_ Colonies. | Colonies. Colonies.
Orhour He woe Sh eee ee fee1eO00)| 520 | 1,300
2 OUTS eee oe eee | 1, 800 0 | 0
Gi ous eee ak pees es | 2,100 0 | 0
PAS OUTS 2S & Bees see se eee 18, 000 0) 0

|

100—yII

50,000 100,000 | 500,000 1,000,000

| parts of | parts of | parts of | parts of
water. water. water. | water.
Colonies. Colonies. | Colonies. | Colonies.

2, 800 650 520 ;

45 0) 25 1, 100

0 | 0 0 30

0 | 0 0 0

EFFECT OF COPPER UPON WATER BACTERIA.

Taste XIII.—EH fect of copper sulfate upon Bacillus sublanatus.

Duration of exposure to action

63

eae Check. 10,000 25,000 50,000 | 1,000,000

of copper sulfate. parts of | parts of | parts of | partsof | parts of | parts of

water. water. water. water. water. water.

ees eRe Bn Bs

Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
ON OUI ee sore aan s Seec een 12, 500 780 2, 700 2,100 | 1,100 | 2, 100 1, 500
DAMON eee a abt eee ee 12, 000 0 0 0 0 35 190
GPO UMS pee ery ernest oceene 12, 500 0 0 0 0 0 80
Oi NOUR ES See eas Seat Sere 40, 000 0 0 0 il 0 0

Taste XIV.—Ffect of copper sulfate upon Micrococcus radians.
1 part copper sulfate to—

Duration of exposure toaction’ Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000 | 1, 000, 000
DOES : parts of | parts of | parts of | parts of | parts of | parts of

water. water. water. water. water. water.

Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
OBO Wee es a ree 1, 200 2,700 10, 500 1, 700 3, 800 2, 500 2, 800
D INOW Sasasecsucseacs saaauesae 1, 200 1 0 alt 20 85 10
GHOULS epoca on see eee 1, 400 0 0 0 0 0 1
DAB OUTS ae ee eee eee ian ses 1, 900 0 0 0 0 0 0

TasLeE X V.—Effect of copper sulfate upon Pseudomonas radicicola (alfalfa).

Duration of exposure to action

1 part copper sulfate to—

25, 000

Check. 10, 000 50, 000 100,000 | 500,000 | 1, 000, 000
Of copperisuliate: parts of | parts of | parts of | parts of |-parts of | parts of
water. water. water. water. water. water.
Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
Osi OUI se etree eae eee 270 300 330 425 3, 700 700 290
DANOUILSH See ie ea eee 210 - 0 0 0 0 0 0
GROUT Sten sects See cere aves 220 0 0 0 0 0 0
DAR OURSHE A eee soo mee esl) 0 0 0 0 0 0

TaBLE X VI.—EKffect of copper sulfate upon Bacillus violaceus laurentius.

1 part copper sulfate to—

Duration of exposure to action Check 10.000 25.000 50.000
of copper sulfate. parts of | parts of | parts of
water. water. water.
Colonies. | Colonies. | Colonies. | Colonies.
OPI OUTER ci Ser ce Sows 7, 200 120 480 740
RIO UR Greer eects aoe oe alert 5, 300 0 0 0
GeHOUTSE or ye eee ease Wi 6, 800 0 0 0
ASO UMS eee ee etn ee nee 40, 000 0 0 0

100,000 | 500,000 /1, 000, 000
parts of | parts of | parts of
water. | water. | water.
Colonies. | Colonies. | Colonies.
470 210 | 520

0 1 25

0 0 0

0 0 0

TasLtE X VII.—Effect of copper sulfate wpon Pseudomonas amethystina.

Duration of exposure to action

1 part copper sulfate to—

: : Check. 10,000 25,000 50,000 100,000 | 500,000
of copper sulfate. parts of | parts of | parts of | parts of | parts of |
water. water. water. water. | water.
|
|
Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
Opn OUI esc See 140 540 90 70 580 670
D INOUE Se eS aA ee Ee ee 190 0 0 i 3 3
GROUT eee eee ee eee 240 0 0 0 0 if
PML VON SS SES 5 ose eee (Dnata 0 0 0 0 0

1,000,000.
parts of
water.

Colonies.
660
15
iL
0

100—viI

64

MISCELLANEOUS PAPERS.

TasLE X VIII.— Effect of copper sulfate upon Bacillus caudatus.

| 1 part copper sulfate to—
Duration of'exposuré to ection ol copper) cheek. | 10,000 | 50,000. || 100,000"||, enon | auaan acne
Fi : | parts of | parts of parts of | parts of | parts of
water. water. water. water. water.
Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
Qu OWT os Bea ects ee eee 875 60 680 2,100 15 70
DNV OURS 2 52s cree mee ee yee uae eee ENOL 390 0 0 iL 0 0
OPO UTS ees oe a ey see lame eea 400 0 0 1 0 0
DATO UNS SE Tee See ae We eee ee 9, 000 0 0 | 0 0 0
TasLe XIX.—Effect of copper sulfate upon Bacillus rubrum.
1 part copper sulfate to—
peer Seer acon’ Check. | 10,000 | 25,000 | 50,000 | 100,000 | 500,000. | 1,000,000
; : parts of | partsof | parts of | parts of | parts of | parts of
water. water. | water. water. water. water.
Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
QU OUTER S ie en. aoe tee 175 10 30 225 90 210 135
DOMES tee wes 2 eens tee er 195 0 07 90 0 0 0
GU OULTS i. Se eeseeate ts ets one ie Sere eee 50 0 0 | 5 | 0 0 0
DAS OUTS So 0e see teres oe ees aie eae 1, 050 0 0 5 | 0 0 0

EFFECT OF CARBON DIOXID ON VIABILITY OF BACILLUS COLI
AND BACILLUS TYPHI.

A careful study of the gas content of both tap and triple distilled
water has shown that for the typhoid and colon bacilli the presence of
carbon dioxid in the water is associated with heightened resistance to
toxic agents, such as solutions of copper salts, precipitated copper
salts, and copper metal. This is the more strange when one considers
that the presence of carbon dioxid in water causes the copper to
remain in solution, and in case of insoluble copper, either precipitated
or metallic, the carbon dioxid serves to bring a considerable amount
of copper into solution. It should be noted, however, that water
heavily saturated with carbon dioxid is toxie to Bacillus coli and
Bacillus typhi.

A series of experiments designed to test the effect of carbon dioxid
on Bacillus coli, the various conditions of triple distilled water with

and without copper, triple-distilled water plus calcium carbonate with

and without copper, and tap water with and without copper are tabu-
lated below. :

TasLe XX.—Tovicity of copper sulfate to Bacillus coli in the absence of carbon dioxid.}

| 1 part copper sulfate to—
Duration of exposure to action of copper! Check, «| "10,000 ||| 50,000, | fn0000 jmpou 000m) st 0 000
8 oe | parts of | parts of | parts of | parts of | parts of
water. water. water. water. water.
| Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Coionies.
QUOT eas eee ee arene ree nave ay ara ae | 6, 800 : 2, 300 2, 200 900 3, 900
D WOWPSs acre gS eee RO A ee ane eee ae | 5, 100 0 0 0 2 80

1 Experiment conducted in Weber resistance glass test tubes each containing 10 c. c. of water triple
distilled from glass, portions of which had been treated previously with the desired amount of

copper sulfate.

Prof. Theobald Smith. The temperature during this experiment varied from 18° to 22° C,

100—yII

Ail tubes inoculated with a 2 mm. loop of culture of Bacillus coli received from

a

‘

EFFECT OF COPPER UPON WATER BACTERIA. 65

Taste XXI.—Hfect of carbon dioxid upon toxicity of copper sulfate to Bacillus coli.

1 part copper sulfate to—

Duration of exposure to action of copper Gheck 10.000

SF. 50,000 100,000 | 500,000 | 1,000,000

parts of | parts of | parts of | parts of | parts of
water. water. water. water. water.

Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
(D) TAC WER SS Se Re ee ee cee 9, 200 - 8,200 5, 800 11, 600 7, 500 6, 200
DEH OURS Ce nome sake enews = Monica oe neumietersis 2,000 0 110 38 900 350

1 Experiment conducted in Weber resistance glass test tubes, each containing 10 c.c. of water triple
distilled from glass, portions of which had been treated previously with the desired amount of copper
sulfate. All tubes inoculated with a 2mm. loop of culture of Bacillus coli received from Prof. Theo-
bald Smith. The temperature during this experiment varied from 18° to 22° C.

Taste X XII.—Lifect of water containing calcium monocarbonate and various quantities
of copper sulfate upon Bacillus coli.*

1 part copper sulfate to—

Duration of exposure to action of copper:

SHE 10,000 50,000 100,000 500,000 | 1,000,000
° Check. | parts of | parts of | partsof | parts of | parts of

water. water. water. water. water.

Colonies. | Colonies. | Colonies. | Colonies. | Colonies.| Colonies.
oF

Op OUT are Sa snc Ge Sinc eee ona e wane eeek 2, 950 3,510 2,670 3, 150 4, 290 3, 760
GUNOUUS Sees ase etarsaee Ones seine Sain eee ee 240 0 ‘ 0 0 105 80
Dal TARO ORES SAE SN gates pn SIS oa Se Rh hae 5 0 0 0 | 0 0

\

1 Various dilutions of copper sulfate were tubed in Weber resistance glass, thoroughly boiled, a small
measured quantity of calcium carbonate added to each tube, and these solutions cooled and kept in
a Novy jar in an atmosphere free of carbon dioxid. All tubes inoculated with a 2mm. loop of cul-
ture of Bacillus coli received from the Bureau of Animal Industry and isolated from hog. The tem-
perature during this experiment varied from 18° to 22° C,

TasLE X XIII.—Effect of carbon dioxid content of water containing calcium carbonate
and various quantities of copper sulfate upon Bacillus coli.*

1 part copper sulfate to—

Duration of exposure to action of copper Ghe ele

Saitates 10, 000 50,000 | 100,000 500,000 | 1,000,000 .

parts of | parts of | parts of | parts of | parts of
water. Water. | water. | water. | water.

Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.

ABINO Watts eeeecie ac cie sai = ae ceicicleicie siestere 4, 650 4, 730 3, 850 3, 980 | 4,100 4, 470
@ LNG UIESS SoS sec esuescce se eEeE oe eos oeseeee 4, 500 0 0 5 | 415 620
0 15 60

2. INGUIN. = Eo eE ae as gaeiaee a Sea aneeee 5, 200 0 205)

1Various dilutions of copper sulfate were tubed in Weber resistance glass, thoroughly boiled, a
small measured quantity of calcium carbonate added to each tube, and these solutions cooled and
kept in a Novy jar in an atmosphere composed largely of carbon dioxid. All tubes inoculated with
a 2mm. loop of culture of Bacillus coli received from the Bureau of Animal Industry and isolated
from hog. The temperature during this experiment varied from 18° to 22°C.

TasLe X XIV.— Toxicity of copper sulfate to Bacillus coliin tap water free of carbon dioxid.*

|

1 part copper sulfate to—

Duration of exposure toaction ofcopper | Check. | 49,900 | 50,000 | 100,000 | 500,000 | 1,000,000
ae parts of | parts of | parts of | partsof | parts of

water. water. water. | water. water.
| eae i |S eS E ( eetcieee se

| | |
Colonies. | Colonies.| Colonies. | Colonies. | Colonies. | Colonies. -

OREO UT Se AS seas wena Sasnese cowee nes 6, 800 |. 7,600 6, 000 | 1,050 | 4,800 5, 200
2 AQT 2 82 ae ie ee 1,500 0 0 |- 07} > > Lostt 60
o LOSS Se oe toc Bee aac ee eee 280 | Ae) 0 | 0 | 0 0
Su) TTI eae en oe on ee 0 0 0) 0 | 0 0

1 Experiment conducted in Weber resistance glass test tubes, each containing 10 c.c. of Potomac tap
water, portions of which had been treated previously with the desired amount of copper sulfate.
All tubes inoculated with a 2mm. loop of culture of Bacillus coli received from the Bureau of Anima]
Industry, isolated from hog. The temperature during this experiment varied from 18° to 22° C.

18270—No. 100—07——5

>

66

MISCELLANEOUS

PAPERS.

TABLE XX V.—Towvicity of copper sulfate to Bacillus coli in tap water free of carbon dioxid.?

Duration of exposure to action of copper

sulfate.

wt ee ee ee eee ee te eee ee ee ee

1 part copper sulfate to—

Check. 10,000 50,060
| parts of | parts of

water. water.
| Colonies. | Colonies. | Colonies.
4, 600 1, 800 4, 800
1, 450 0 0
1,500 0 0
250 0 0

/ 100,000
parts of
water.

3, 700
20

0
0

| Colonies.

500,000
parts of
water.

Colonies.

1,000,000
parts of
water.

Colonies.
4,000
100
2
0

1 Experiment conducted in Weber resistance glass test tubes, each containing 10c. ce. of Potomac tap
water, portions of which had been treated previously with the desired amount of copper sulfate.
All tubes inoculated with a 2mm. loop of culture of Bacillus coli received from Prof. Theobald Smith.
The temperature during this experiment varied from 18° to 22° C.

TABLE XX VI.—Effect of carbon dioxid upon toxicity of copper sulfate to Bacillus coli.*

Duration of exposure to action of copper | Bel
sulfate. Check. |

| Colonies.
(1) oVORUN eos Se ss Semen Cems eestay peg en eee dia | 4,200 |
OXON SIE Sid ot et rec ere ese Sint eas 2,800 |
GRINO WSR ee es hee eee eae PE Ce 1, 460 |

DART OULS Aare ese eee ee ies pert ey |

|
|
|
}

1,540 |

1 part copper sulfate to—

{
10,000 | 50,000 100,000 500,000 | 1,000,000
parts of | parts of | parts of | parts of | parts of
water. water. water. water. water.
Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
4,000 | 9, 800 1,270 5, 100 1,100
10 | 0 0 110 260
15 15 20 10 35
0 0 0 0 0

1 Experiment conducted in Weber resistance glass test tubes, each containing 10 c.c. of Potomac tap
water, portions of which had been treated previously with the desired amount of copper sulfate.
All tubes inoculated with a 2mm. loop of culture of Bacillus coli received from the Bureau of Animal
The temperature during this experiment varied from 18° to 22° C.

Industry, isolated from hog.

TasBLeE XX VII.—Effect of carbon dioxid upon toxicity of copper sulfate to Bacillus coli.'

Duration of exposure to action of copper

JANN OUMSe seer eereeee ee Be ee

sulfate.

| 1 part copper sulfate to—
Check. 10,000 90,000 100,000 500,000 | 1,000,000
parts of | parts of | parts of | parts of | parts of
| water. water. water. water. water.
| |
Colonies. | Colonies. | Colonies. | Colonies. | Colonies. Colonies.
3, 800 3, 000 8, 500 5, 200 . 4, 400 5, 500
2,300 0 5 15) 2,150 1,500
1, 600 10 12 10 120 100
3, 500 0 0 10 35 0

1 Experiment conducted in Weber resistance glass test tubes, each containing 10 ec. c. of Potomac tap
water, portions of which had been treated previously with the desired amount of copper sulfate.
All tubes inoculated with a 2mm. loop of culture of Bacillus coli received from Prof. Theobald Smith.
The temperature during this experiment varied from 18° to 22° C.

An examination of the foregoing tables shows that with the three
types of water the presence of carbon dioxid increases the resistance of

the bacilli in question.

In the solution containing monocarbonate of

lime and copper sulfate the bacteria are extremely sensitive, even the
bacteria in the check solutions dying rapidly, while in the solutions
charged with carbon dioxid the bacteria were able to persist in con-
siderable numbers in the dilute copper solutions in spite of the fact

that most of the copper must have remained in solution.

This point

is interesting in connection with the work of Engels,“ who reports a

«Weitere Studien tiber die Sterilization von Trinkwasser auf chemischen Wege.
Centralbl. i. Bakt., Parasit., u. Infekt., vol. 32 Orig., 1902, pp. 495-021.

1v0—VII

EFFECT OF COPPER UPON WATER BACTERIA. 67

rather high toxicity for calcium chlorid, and of Pfuhl,“ who suggests
a calcium salt—milk of lime—for water sterilization. The use of lime
or a similar agent may be highly desirable in connection with treathe
a contaminated reservoir with copper, though the inferior germicidal
power of lime makes it improbable that the latter alone could be used
safely. ;

In regard to chemical water analysis, it seems probable that the
determination of carbon dioxid or the determination of monocarbon-
ate and bicarbonate alkalinity may have importance hitherto unrecog-
nized, and the variations in the longevity determinations of Bacdllus coli
and Bacillus typhi may be due in part to the mineral constituents of a
water, in part to methods of experimentation, and in part to the car-
bon dioxid content. Extended field tests must be made before gen-
eralizations on the possible effect of the gas content of a water supply
can be determined. :

The carbon dioxid content of a water may possibly explain the
peculiar results obtained by Clark and Gage.’ They have reported
practically no toxic action from metallic copper, or at least very little
difference in the action of metallic copper, iron, tin, zinc, and lead.
Their figures are rather misleading because of the great number of
days the experiments were carried on, and, as Phelps’ has shown,
metallic copper is coated with some insoluble substance after a few days’
exposure to Boston tap water and no longer has great toxic action.
The lack of toxicity of metallic copper and the similarity of its action
to the action of other metals, as reported by Clark and Gage, is
entirely at variance with the work of Kraemer,’ Pennington,’ Gil-
dersleeve,’ Stewart,’ and Moore and Kellerman.” Investigators
generally have agreed that it would be possible to practically sterilize

« Uber die Disinfection der Typhus and Cholera-ausleerungen mit Kalk. Zeitschr.
i. Hyg. u. Infekt., vol. 6-s, 1889, pp. 97-104.

The Use of Copper Sulphate in Water Filtration. Journal of Infectious Diseases.
Supplement No. 2, February, 1906, pp. 172-174.

¢ Experiments on the Storage of Typhoid Infected Water in Copper Canteens.
Public Health Papers and Reports, American Public Health Association, vol. 31, part
1, 1905, pp. 75-90. -

@Copper Treatment of Water. American Journal of Pharmacy, vol. 76, December,
1904, pp. 574-579.

The Use of Copper in Destroying Typhoid Organisms and the Effects of Copper on
Man. American Journal of Pharmacy, vol. 77, June, 1905, pp. 265-281.

eThe Action of Electrically Charged Copper Upon Certain Organisms in Water.
American Journal of Medical Science, vol. 129, 1905, pp. 751-754.

f Studies on the Bactericidal Action of Copper on Organisms in Water. American
Journal of Medical Science, vol. 129, 1905, pp. 754-760.

9A Study of the Action of Colloidal Solutions of Copper upon Bacillus Typhosus,
American Journal of Medical Science, vol. 129, 1905, pp. 760-769.

% Buls. 64 and 76, Bureau of Plant Industry, U. S. Dept. of Agriculture.

100—vir

68 MISCELLANEOUS PAPERS.

drinking water by exposing it to the action of clean metallic copper.4
Perhaps this opinion should be qualified by adding that the action is
more rapid if the water contains no free carbon dioxid, although the
following tables show only slight differences between the toxicity of
metals because of the presence or absence of carbon dioxid.

TaBLeE XX VIII.—Effect of carbon dioxid upon toxicity of metals to Bacillus coli.

|

Duration of exposure to action of metals. | Check. | Copper. Iron.2 | Zine. | Lead. Tin.

| Colonies. | Colonies. Colonies. Colonies. | Colonies. | Colonies.

(Oi avo YD NOs Sey eee eae bee, Pet A hed Mee Rear eee 3,700 1,100 | 3,300 | 3, 050 3, 700 3, 500
A NOUISS- 23s Feaasa ear en es ae anon wen one 440 7d 30 | 125 | 275 410
SIN OUTS Sere ep thes Na oe La Se 305 3 3 30 | 120 190

1 Experiment conducted in Weber resistance glass test tubes, each containing 10 c. c. of water triple
distilled from glass, to portions of which were added sterile blocks of the proper metals, each having
approximately 2 sq. cm. surface area. All tubes inoculated with a 2 mm. loop of culture of Bacillus
coli received from Prof. Theobald Smith. The temperature during this experiment yaried from 18°
to 22° C.

2Tron impure and presumably more toxic than pureiron. (See Table No. XXII.)

TaBLeE XXIX.—Tovicity of metals to Bacillus coli in the absence of carbon dioxid.'
Duration of exposure to action of metals. Check. | Copper. | Iron.? | Zine. | Lead. | ‘Tin.

Colonies. | Colonies. | Colonies. | Colonies. | Colonies. | Colonies.

WHGUL-e aegis Saxena ee eee oe Loe 2s Q50: lee e300 1, 200 | 1,450} 1,300] 1,600
MSH ites Ss ee Spee, eee ee | 965 | 10 10 65 | 40 770
SUR OUTS Hee tees Beene aes Sn eee 740 0 0 | 5 | 5 | 700

1 Experimeat conducted in Weber resistance glass test tubes, each containing 10 c. c. of water triple
distilled from glass, to portions of which were added sterile blocks of the proper metals, each having
approximately 2 sq. cm. surface area. All tubes inoculated with a 2mm. loop of culture of Bacillus
coli received from Prof. Theobald Smith. The temperature during this experiment varied from 18°
to 22° C.

2Tron impure and presumably more toxic than pureiron. (See Table No. XXII.)

«There is a seeming discrepancy in this statement due to the fact that Mr. Earle
B. Phelps, assistant hydrographer, U. S. Geological Survey, has carried on experi-
ments on the storage of typhoid infected water in copper canteens, some results of
which, with conclusions of a nature unfavorable to the use of metallic copper in
practically sterilizing water, were issued in a press circular of the Geological Survey.
A quotation from Mr. Phelps’s paper paralleled with a quotation from Bureau oi
Plant Industry Bulletin No. 76 shows clearly that Mr. Phelps’s work is a corrobora-
tion instead of a contradiction of the fact reported in Bulletin No. 76 that metallic
copper has a high germicidal value. Mr. Phelps has stated: ‘‘The fact that organisms
do survive the copper treatment even in small numbers [Per cent reduction usually
over 99.999.—K. F. K.] seems, in the writer’s view, to lessen considerably the value
of the canteen as a safeguard against typhoid infection. A second point of interest
is the fact that the efficiency of the canteen decreases as time goes on, probably
owing to the accumulation on the surface of the copper of a film of basic carbonate
or other insoluble copper compound.’’ A paragraph from Bureau of Plant Industry
Bulletin No. 76 reads as follows: ‘‘Complete sterilization is a standard to which even
the best filters seldom attain, and under the most unfavorable conditions the reduc-
tion in the number of bacteria in water exposed to the action of metallic copper for
twelve hours will be approximately as great as filtered water. The copper must be
_ kept clean, not, as is popularly supposed, to protect the consumer from copper
poisoning, but because it is possible for the metal to become so coated with foreign
substances that theres is no longer any contact of copper and water, — hence no
antiseptic action.’

100—VII

"
7. Va

EFFECT OF COPPER UPON WATER BACTERIA. 69

_ To determine whether the peculiar variation in the germicidal power
of solutions or metals is due to the use of ordinary laboratory glassware
made of a rather soluble glass instead of carefully selected highly
insoluble glass, a parallel series in good and poor glass was carried on.
The following tables show the slight difference in results:

TABLE XX X.—E fect of glass upon toxicity of metals to Bacillus coli.

Duration of exposure to action of metals.| Check. | Copper. Iron. | Zine. Lead. Tin.

| Colonies. | Colonies. | Colonies. | Colonies. Colonies. | Colonies.

Onur aes teen or eh 2,600 | 1, 925 1, 850 2, 450 2, 600 3, 100
QUNOUTSa eee ee 8 SE eR es Ro 2, 650 | 779 2,100 715 | 2, 800 | 2,300
(G1 OX OND BSUS 2, Aes ae eee er I ee ee ae 2,700 525 2,350 70 | 2, 450 4. 200

DAC OWS oer cress ei eee cae eisieis see Relaciones [tae 20s. OOO 15 4,350 | 1} 13,750 | 12, 000

if

1 Experiment conducted in ordinary glass test tubes each containing 10 ec. c. of water triple distilled
from glass, to portions of which were added sterile blocks of the proper metals, each haying approxi-
mately 2 sq. em. surface area. All tubes inoculated with a 2 mm. loop of culture of Bacillus colt
aso from Prof. Theobald Smith. The temperature during this experiment varied from 18° to

TABLE X X XI.—Effect of glass upon toxicity of metals to Bacillus coli.

|

| | |
Duration of exposure to action of metals. Check. Copper.| Iron. | Zine. Lead. | Tin.

. ’ . | Y * | ce ¥ . .
Colonies. - Colonies. | Colonies. | Colonies. , Colonies. | Colonies.
. | i>)

ORIN O UI he ae ne ere emcee ae ais a 2,300 4,825 | 4,750 | 2,400 2, 800 3, 000
D3 OXOND LS (Soe ee es ae ne ee eOn2 975 | 2,400 | 200 1, 800 3, 600
GNOMES A ae a a ee ek S aa eS 1, 400 190 | 3, 050 20 2, 000 3, 850

PASO UTS Baers leet tops qe en eee sl ae ee 10, 825 if | 6, 700 | 1 | 19,000 14, 000

1Experiment conducted in Weber resistance glass test tubes each containing 10 c. c. of water triple
distilled from glass, to portions of whith were added sterile blocks of the proper metals, each having
approximately 2 sq. em. surface area. All tubes inoculated with a 2 mm. loop of culture of Bacillus
coli received from Prof. Theobald Smith. .The temperature during this experiment varied from 18°
to 22° C.

COPPER SULFATE AND FILTRATION.

The use of copper sulfate in connection with filtration has been
mentioned in previous bulletins. Further experiments in this field
show that in mechanical filtration with alum it is necessary to limit
the use of copper sulfate to treatment some hours before coagula-
tion. When solutions of aluminum sulfate and copper sulfate are
mixed and alkali or hard water is added in quantities sufficient to
cause precipitation the copper is coagulated at once, while the alu-
minum is deposited on the copper and incloses it, with the result that
the copper-alum coagulum is no more toxic than is the pure alum coag-
ulum. When copper and iron salts are precipitated together the
reverse of this seems to take place and the precipitate retains its toxic
properties.“

@See also H. W. Clark, Sulphate of Alumina as a Germicide. Thirty-sixth Annual
Report of State Board of Health of Massachusetts, 1904, p. 288.
100—vit :

70 MISCELLANEOUS PAPERS.

The following table shows the various combinations of precipitates
tested and the exact results:

TaBLe XX XII.—Tozicity of combined precipitates to Bacillus coli.

| |
=! | Copper
Duration of exposure to action of . | Copper Iron | Alumi- | Copper arias ie
eth -| Check. : num jandiron! “-:

precipitate. hydrate. } hydrate. hydrate. | hydrate, | 272um

Nees SS ‘| hydrate.

| Colonies. | Colonies. | Colonies. _ Colonies. | Colonies. | Colonies.
OUR OUTS. S35 See ee eee ene. 2,250 } 1, 525 645 7,790 3, 450 | 1, 750
DN OUTS ae neon eee Se eee ee eae 675 0 230 1, 800 25 320
GnOUTS =. os een eee ee oe eee ners 465 | 0 230 195 0 15
DAN OUTS eiaseas cee ea cee ee ae oer see 165 0 230 | 5) 0 | Ht

1Experiment conducted in 100 c.c. Jena glass flasks, each containing 15 mg. of the proper precipi-
tate. All flasks inoculated with a 2mm. loop of culture of Bacillus coli received from Proi. Theobald
Smith. The temperature during this experiment varied from 18° to 22° C.

TaBLeE XX XIITI.—Tozxicity of combined precipitates to Bacillus coli.

| | | | | .
| | Alumi- | Copper | Copper

Duration of exposure to action of Gucci | Copper |_ Iron and alu-

zat | d iron | :
precipitate. | hydrate. |} hydrate. nur ay | minum
| hydrate. | hydrate. | hydrate.
| Colonies. \Colonies. | Colonies. | Colonies. | Colonies. | Colonies.
Quh OUR Sao eecs Srctea ec ateee te cece acees | 3, 800 | 380 | 1, 065 2, 650 3, 100 | 2, 390
DON OUTSE ean vem es oo Se araa ainas Ee eel aemsee 305 | 0 | 1,900 | 3 1 | 80
Ovh OUTS LBS es gaa Se coacnne eee eee 300 | if 1, 350 | 1 0 0
DAN OUTS Seen erect Sane ee eae aan ae ee | 200 0 | 850 | 1 0 | 0

|

1 Experiment conducted in 100 c.c. Jena glass flasks, each containing 15 mg. of the proper precipi-
tate. All flasks inoculated with a 2mm. loop of culture of Bacillus coli received from the Bureau of
ae Industry, isolated from hog. The temperature during this experiment varied from 18° to

The presence or absence of carbon dioxid is probably important in
this connection. If the laboratory results will hold for field condi-
tions, a copper precipitate or a precipitate of iron and copper will
be highly toxic to Bacillus coli and Bacillus typhi in a water whose
alkalinity is chiefly monocarbonate; and, conversely, the action of a cop-
per precipitate or a copper-iron precipitate will be reduced if a water
contains free carbon dioxid. This is probably the reason that small
quantities of copper are toxic” ina mechanical filter using the proper
quantities of iron and copper, and gives an additional reason for the
advice given by Ellms?and Brown“ that before filtration or distribu-
tion of a copper-treated water all free carbon dioxid and part of the
semicombined carbon dioxid should be neutralized by caustic lime.
Copper treatment of water previous to slow sand filtration should be
made under similar conditions, and as this is seldom practicable it is
perhaps advisable to limit the use of copper in connection with slow
sand filtration to treatment after passing the filter, and before distri-
bution the proper quantity of caustic lime may be added. An excel-

¢Bul. 76, Bureau of Plant Industry, U. S. Dept. of Agriculture.

6 Journal New England Water Works Association, vol. 19, 1905, pp. 496-503.
¢ Journal New England Water Works Association, vol. 19, 1905, p. 578.
100—VII

EFFECT OF COPPER UPON WATER BACTERIA. (a

lent example of the results to be expected from incorrect use of copper
in connection with slow sand filtration is furnished in Clark’s“% report.
Not only was copper found in the effluent of the experimental filter,
but Bacillus cola was found in a rather high per cent of the bacterial
samples.

The carbon dioxid content of the Ohio River is a possible explana-
tion also of the fact reported by Brown? that samples of Ohio River
water yielded between 0.00772 and 0.00657 grain of metallic copper to the
gallon, though Lacillus coli was occasionally present. To use his own
words, ‘‘ It is seen from the work done, as above stated, that the copper
is present in an insoluble form and probably as the oxid united with
the suspended mineral matter which the water carries. If inthis form
it would be unable to exert any germicidal power, and, as far as could
be determined, this seems to be the case. It was decided that the cop-
per was present in a spent condition.” As there was no monocarbon-
ate alkalinity noted, the Ohio River water at this time doubtless
contained some free carbon dioxid, and from the analogy of the labora-
tory results it seems fair to assume that Brown’s explanation must
be supplemented by the theory of the heightened resistance of Bacal-
lus coli due to carbon dioxid.

« Journal New England Water Works Association, vol. 19, 1905, pp. 505-505.
6 The Purification of Water at Marietta, Ohio. Official Report to Board of Public
Service, 1906.
100—vi1

B. P. I.—233.

VIIT—CONDITIONS AFFECTING LEGUME INOCULA-
TION.

By Karu F. Ketierman, Physiologist in Charge of Soil Bacteriology and Water
Purification Investigations, and T. R. Rosrnson, Assistant Physiologist.

s

INTRODUCTION.

The widespread use of bacteria for inoculating leguminous crops
has made possible more accurate study of the conditions under which
a particular species of legume might be successfully inoculated and
the conditions under which failure to obtain inoculation might be
expected. Inoculation tests carried on in different soils and under
different cultural and climatic conditions but. using the same stock
culture have shown results so conflicting in certain cases that one is
bound to be misled by any general statement based on one factor
alone, such, for instance, as the condition of the bacteria used.

To accept as indicative of the general usefulness of pure cultures
results obtained on a single type of soil is clearly opposed to progress
alone a line of investigation now recognized as closely connected with
soil fertility problems. The advantage of numerous tests covering
many types of soil becomes increasingly apparent. The effect of pre-
vailing cultural practices is no less to be considered; aeration by cul-
tivation, the use of lime, and the effect of such factorson the bacterial
flora, the bacteriological testing of the soil itself—all these problems
call for extensive field experiments to determine how far they may
become part of practical routine for successful farming.

The work here recorded emphasizes the intimate connection of soil
bacteriology with certain phases of soil fertility. Soil fertility is a
strictly relative term; it is possible for a soil to be fertile in regard to
one crop and unfertile in regard to another, the conditions of tem-
perature and moisture being optimum in each case. The interaction

«The identification of soil bacteria and their distribution in and correlation with
different types of soil, the changes in the bacterial flora with different modes of
treatment and different systems of rotation, the individual and combined action of
the species in producing changes in the soil favorable or unfavorable to plant growth,
the introduction of favorable species and groups of species and their improvement
by selection or special cultivation, and the elimination of unfavorable forms are
problems calling for extended investigation; but with the information already at
hand and work under way both in this country and in Europe it is not too much to
expect large increases in our present knowledge along these lines. —B. T. GaLLoway,
Pathologist and Physiologist, and Chief of Bureau. =

100—virr 73

ee MISCELLANEOUS PAPERS.

between prevailing soil conditions and biological phenomena becomes
apparent at once and lends confirmation to the belief that in practice
cecological conditions may be so modified as to promote the activity
of the desirable organisms and retard the development of the unde-
sirable, although under certain conditions the control of the bacterial
flora undoubtedly will depend upon the introduction of virile cultures
of desirable bacteria.
USE OF LIME.

Samples of soil have been obtained from fields in various parts of
the United States where attempts to inoculate legumes have failed, and
greenhouse tests have been made combining various quantities of air-
slaked lime with these soils. The effect of applying lime to certain
types of soils is rather striking when nodule formation is considered.? —
This is especially true of those soils which give an acid reaction to lit-
mus,’ although several of these unfavorable soils did not give an acid
reaction to litmus, but were nevertheless benefited by lime. Outlines
of a few typical cases selected from our experiments follow.

«The fact as shown in numerous cases that legumes can be successfully inoculated
by the use of pure cultures of the nodule-forming organisms with a consequent large
gain in yield and amount of nitrogen fixed is in conflict with the statement that ‘‘An
enhancement of the desirable bacterial activities of the soil can only be encouraged
by the proper improvement in the physical and chemical composition of the soil.’’
(Lipman, ‘‘The Measure of Soil Fertility from the Nitrogen Standpoint,’”’ N. J. Agr.
Expt. Sta. Rept., 1905, p. 243.)

bFruwirth. Neue Impfversuche mit Lupinen. Deutsche Landw. Presse, vol. 18,
1892, pp. 18 and 127.

Fruwirth. Dreijihrigen Impfversuche mit Lupinen. Deutsche Landw. Presse,
MOlESIOS 1893p. G6:

Heinrich. Action de la chaux sur les lupins. Zweit. Ber. Landw. Versuchsst ,
1894, p. 272.

Passerini. Sur l’influence améliorante des légumineuses dans des sols de composi-
tions différentes. Staz. Sper. Agr. Ital, vol. 30, 1897, p. 68.

Deherain and Demoussy. Recherches sur la végétation des lupins; deuxieme
partie, Lupins bleus. Ann. Agron., vol. 26, 1900, p. 169.

Deherain and Demoussy. Etudes sur les légumineuses de grande culture. Lupins
jaunes. Ann. Agron., vol. 28, 1902, p. 449.

Bilwiller. Cited by Miller. Journal Roy. Agric. Soc. England, 1896, pp. 236
and 423.

Mazé. Les microbes des nodosités des légumineuses. Ann. Inst. Pasteur, vol. 13,
1899, p. 145. :

Salfeld. Vernichtung der Leguminosenpilze durch #tzkalk. Deutsche Landw.
Presse, vol. 21, 1894, p. 785. i

Tacke. Action de la chaux vive sur les bactéries des tubercules des légumineuses.
Centralbl. f. Agriculturchemie, vol. 25, 1896, p. 297.

eG. A. Billings (N. J. Agr. Expt. Sta. Rept., 1905, p. 358) shows the efficient action of
lime in promoting the growth of alfalfa and that the vigor of the plants seemed to be
correlated with the form and greater abundance of root nodules. He suggests that
soil acidity, conditions of ventilation or soil porosity, and different bacteria which
may influence the form of the nodules are determining factors, controlled at least
partially by the action of lime.

106—VIII

Ray

CONDITIONS AFFECTING LEGUME INOCULATION. 75

A quantity of soil was obtained from Blue Hill, Me., where the
culture tried last year had shown no benefit with garden peas. One
portion of this soil was placed in ordinary greenhouse pots; a second
portion was thoroughly mixed with pulverized lime at the rate of 1 ton
to the acre, approximately, and placed in similar pots, and inoculated
seed sown in half of each series. Of 15 plants unlimed, 10 were with-
out nodules, 5 having a single nodule each; of 17 plants limed, 15 were
well noduled and 2 apparently free, but nodules were evident on close
examination. The uninoculated pots in the unlimed series had no
nodules; in the limed series there were only a few scattering nodules,
the majority of the plants, 10 out of 18, being free.

This experiment was repeated, the soil itself being inoculated with
the liquid culture, with results even more striking. Of 17 plants
unlimed, 12 were without nodules, 5 having a total of 8 nodules; of 16
plants limed, all were well noduled, having a total of STnodules. The
uninoculated pots in the unlimed series had no nodules; in the limed
series, 15 out of 17 plants had no nodules, the other two having a
single nodule each.

The combination of liming and inoculation was again strikingly
shown with alfalfa grown in a poor sandy soil from Lanham, Md.
In this case it seems reasonable to assume that alfalfa bacteria of low
virility were present in the soil. Under the normal unfavorable soil
conditions the native bacteria were unable to produce inoculation, and
the virile ones from the pure culture, while able to inoculate the alfalfa
plants, could benefit them only shghtly. In the limed soil, however,
the native bacteria were able to produce nodules in considerable
numbers and to be of moderate benefit to the plants. The pure cul-
tures of virile bacteria under similar conditions, however, caused more
than double the increase that may be ascribed to the native bacteria.

The following table shows the relative virility of the two types of
alfalfa bacteria in soil from Lanham:

\r |x Average
Number of Numberof; Average =
Treatment. plants. | nodules. | height. ‘ dry
| | | weight.
| | |
Lime: | Inches. | Grams.
Ti CS RE ee oe ey ee ae oa io nieemineineeeee 9 12 | 156) | 0.39
iin OG] abe beeen sie ha hee os aces Scat ces cece 13 | 15 133 | .15
No lime: | | |
ITO C wl aed wepeee cess sree Ge ners ears os cen been ees | 10 | ial | OR . 09
Wiainocul atedeae ce ota on Wats ose cece ease wees | 9 | 0 | Ones . 06
|

Similar results were obtained with a large number of soils concern-
ing which unfavorable reports had been received regarding attempts
at inoculation with cultures furnished by the Department of Agri-

culture. Field observations on the nodule formation of various

legumes showed the effectiveness of using lime or some other agent
100—viit

76 MISCELLANEOUS PAPERS.

to counteract the influence of substances in the soil unfavorable to
the growth of the bacteria.¢

EFFECT OF SOIL CONDITIONS UPON BACTERIA.

The constitution or character of the soil solution has great effect upon
the growth of nodule bacteria as well as upon the formation of nodules. —
In the large number of soil samples tested simultaneously in the green-
house and in the laboratory it seems to hold true generally that the
possibility or impossibility of securing effective inoculation on a par-
ticular crop in a certain soil can be predicted by the relative growth
of the specific culture in the sterile extract of the soil in question.
There also seems to be a somewhat close relation between the soil
solution necessary for the growth of host and bacteria, so that in many
cases, at least, it is possible to determine the suitability of a legume
crop to a certain soil by the growth of the specific culture of Pseudo-
monas radicicola iv the extract of the soil. The probability of an
extract not truly representing the soil solution and the disturbing
factor of sterilizing certain extracts will in some cases introduce error
in interpreting results. The use of sterilized soil extracts as culture
media forthe bacteria has been found to give fairly true indications
of the growth of the respective hosts of these bacteria in a consider-
able series already tested, however, and contemplated improvements
in technique will doubtless increase the probability of securing trust-
worthy indications. The testing of the soil extract in its behavior
toward specific bacteria may even indicate that some treatment is
necessary, but can not prescribe the method of amelioration, and for
the present direct experimentation is necessary to determine the proper
treatment of an unsuitable soil.

Asanexample of the relation between the growth of the specific
bacteria in the sterile soil extract and the growth of the legume host
in this soil may be cited the following result of a fairly representative
test, using different quantities of lime on an unfavorable soil which
responded favorably to treatment with lime: 3

| Number of
Green - bacteria ina
Quantity of lime. weight of pepe Ce | cubic centi-
plant. * | meter of soil
|. extract.
Grams.
Wnilimeds s223255 Pandas Sere oa ee ee eee eee 15) 31 87
Limed: |
2:000: pounds:to theyaere saecer oe enone ay en a x5 | 63 | 71, 950
4,000 pounds: to*thelacneky 22 Aha ee pee Ree eee eee 8.5 | 88 128, 650

| id
@¥For the presence of substances in poor soils deleterious to higher plants, see
Bureau of Soils Bul. No. 28, 1905, ‘‘Studies on the Properties of an Unproductive
Soil.”
100—VvUulI

PLATE VIII.

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture.

Pots oF RED CLOVER, SHOWING THE EFFECT OF LIME ON A SOIL UNFAVORABLE TO THE GROWTH OF CLOVER.

1.—Unlimed. 2.—Limed at the rate of 2,000 pounds to the acre. 3.—Limed at the rate of 4,000 pounds to the acre.

CONDITIONS AFFECTING LEGUME INOCULATION. (age

The accompanying illustration (Pl. VIII) shows characteristic pots of
red clover from a series of soils from South Salem, N. Y., where clover
had been steadily diminishing in vigor for years. The nodules on the
unlimed plants were small and clustered around the crown of the
plant, while the limed plants showed numerous nodules well dis-
tributed. The stand secured in a series of limed pots was four
times as heavy as without the use of lime.

In comparison with this unfavorable soil, the extract obtained from
soil sent in from a favorable field test at Carlisle, Pa., gave an excel-
lent growth of the red clover bacteria, and the inoculated red clover
grown in this soil in pots showed numerous nodules and a better
gr owth than in the uninoculated pots, thus confirming results obtained
in the field.

It may be noted that there is a difference exhibited among different
legumes in their behavior toward lime. While for most legumes its
effect is beneficial, a few species, such as lupine and serradella, are
actually injured by its use® and some other legumes, such as Lima bean
and cowpea, do not respond to lime even in soils where clover refuses
to grow without lime. It has been noted? that serradella is not suc-
cessful when following red clover, and that results are also unsatisfac-
tory when red clover follows serradella. These varying relations
shown by legumes belonging to different groups in their relation to
lime and other conditions emphasize the necessity of determining as
accurately as possible the adaptability of different soils to the crops
for which they are intended.

Observations upon the occurrence of nodules in certain soils have
been found to correspond quite closely with the behavior of the soil
solution toward the bacteria of the legumes tested. The preceding
table illustrates this point, though perhaps not so clearly as the follow-
ing examples.

In the case of a fairly rich garden soil, soy beans would not form
nodules even after very heavy inoculation, and the extract from this
soil used as a culture medium was found to inhibit the growth of the
soy bean bacteria. On the other hand, alfalfa readily formed nodules
in this soil and the soil extract was not unfavorable to the growth of
the alfalfa bacteria.

A soil from Niles, Mich., which had grown a fair crop of soy beans
for four years without the occurrence of nodules, was tested. The
so:l extract in this case was found unfavorable to the growth of the
soy bacteria. In greenhouse pot tests soy beans of several varieties
failed to produce any nodules in this soil even when heavily inoculated
with cultures which produced abundant nodules in other soils tested

@See Rhode Island Agr. Exp. Sta. Rept., 1896, p. 256; also Bul. 96 of same
station, 1903.

> Deutsche Landw. Presse, vol. 32, 1905, p. 799.

10G—VIII

78 MISCELLANEOUS PAPERS.

in comparison. Heavy liming of the soil-extract at the rate of about
6,000 pounds to the acre gave a fair growth of the bacteria, and cor-
responding to this result one pot that received lime in the same pro-
portion produced a well-noduled plant. In this same soil without lime
and without inoculation cowpeas formed nodules abundantly.

A soil from Lanbam, Md., gave an extract which as a culture
medium was distinctly unfavorable to the growth of red clover bac-
teria, and plants of red clover in this soil made a very sickly growth,
producing few nodules. A few pots were boiled by immersing in a
tub of water and blowing live steam into the water; the soil was of a
sandy character, so that there was little danger of puddling from this
treatment. The growth of red clover was markedly improved in the
boiled series and the roots were well noduled after inoculation. The
extract of this soil, sterilized by boiling, had proved an unfavorable
medium for the growth of the bacteria. It is probable, therefore, that
boiling the soil changed the character of the soil solution at least in
regard to the unfavorable materials or conditions which had inhibited
bacterial activity.

Soil from Lanham, Md., was further tested with alfalfa, treating
the soil in three ways: (1) Lime at the rate of one ton to the acre;
(2) lime and one-fourth humus, composed of leaf mold; (8) humus.
The combination of lime and humus gave. the greatest growth and
most abundant nodule formation. With humus alone the growth was
especially inferior and nodules were lacking even where the soil was
inoculated. Inoculation doubled the number of nodules where lime
was used and increased them six times where both lime and humus
were used.

Effect of humus and lime upon the growth of alfalfa in sou from Lanham, Md,

[Ten plants in each series. |

Average

| Average
Treatment. (green) number of
weight of | VET VTLAS
plant. y
Lime alone: Grams.
Um IN OC ulate disse Hee See Oe ae ee 0. 86 | 0.5
TBoKOveRDULe irey6 Leesa ye ee rem ee een Te ee aoe Be a a ee Par eh ee | 1.56 1e0
Humus alone:
Wminocilated ae sae ae Se cr ee ae =) 0
Inoculated ees 2508 ee eee Ae ee ee Re eee ee .8 0
Humus and lime:
TmMLMO Cul ated a ee re Re BE Sy ey ee 08 1.4
ENV OCULAE CC are oe ee ae en ae ee I e020 ra 2.45 8.6
No lime; no humus:
Uninoculated t's 5.25. Faas ree ae ete See oe eee eee (*) .3
Im@culated teas. Mews yas ose eso le See eae aie ae ie tee See eee eae aise (*) .d

* Not weighed; growth so small as to bea practical failure—2 to 5 inches as compared with 12 to 18
inches high in the limed pots or those containing lime and humus.

‘The sterilized extracts of soil from this series of pot tests gave
results seemingly contradictory when used as culture media for bac-
teria in comparison with the growth of plants and nodules. The

100—vilII

CONDITIONS AFFECTING LEGUME INOCULATION. 79

extract of untreated soil gave a growth of the alfalfa bacteria which
might be designated *‘ fair,” while with lime, with lime and humus,
and with humus alone the extracts gave uniformly a growth which
might be designated ‘‘excellent.” In the pots, however, no nodules
developed in the humus series. The sterilization by heat of the
extract from a soil containing such a relatively large quantity of
humus, one-fourth by volume, probably changes the material so that

the solution becomes favorable to the growth of the bacteria, but this

material in the soil pots, not heated, remains unchanged and may in
this form be unfavorable to the activity of the bacteria introduced
into the soil.

Aside from the effect of the soil on nodule formation there seems
to exist a marked difference among different varieties of legumes in
their susceptibility to infection—that is, their readiness to form
nodules. With a similar soil and one which is favorabie to the
growth of the respective species, nodules will occur in abundance upon
one species or variety and another species or variety will exhibit none
or onlya few. This is particularly noticed with varieties of soy beans
and with certain species of Phaseolus, the Lima bean (Phaseolus
lunatus) and some varieties of soy beans being very difficult to inocu-
late. It would seem that such species were actually resistant to
infection, especially in soils rich in nitrogenous matter.

EFFECT OF HEAVY INOCULATION.

The decided advantage of very heavy applications of pure cultures
reported from some field and pot experiments and reports of other
experiments showing that cultures diluted to almost infinitesimal limits
gave as good results as undiluted cultures seem at first diametrically
opposed. Greenhouse tests seem to confirm the beneficial effect to be
expected from heavy inoculation provided excessive quantities of cul- |
ture are applied. The following experiment is fairly representative:

Effect of light and heavy inoculation of garden peas on soil from Blue Hill, Me.

Re [eee Ai |
| Number} Number of} Average

Treatment. | of plants | plants with | number of
| grown. | nodules. | nodules.
Chel avwaHoOuULsMOcCWIAWM ONY == 542 4. ec cco e tes Societe oewie eee anne ee | 11 | 2 | 1
ih ei O CU a alge tee tee ne Ree i ee ieee | 9 | 6 | 3
ICaNp VEIN OCUI ATI OMe tas) ter eee a ce em Ve ee ae | ee 6 | 6 | 7
|

It is here shown that heavy inoculation not only doubled the average
number of nodules upon inoculated plants, but insured all plants
becoming infected; while with light inoculation in this unfavorable
soil one-third of the plants failed to produce nodules, and with no
inoculation nodules were almost entirely lacking.

100—vyIiI

SO MISCELLANEOUS PAPERS.

Garden peas in a garden soil naturally inoculated showed the follow-
ing difference where a heavy inoculation was made:

Effect of heavy inoculation of garden peas on a naturally inoculated garden soil.

Number | Number of| Average

Treatment. of plants/ plants with | number of
grown. nodules. nodules.

Gr ay keV oY Ue Sa ee cS RE ee te Ps a Ue ire Speen the 15 15 62
Elieavay imo Gulla tlony eer serene ees een ee cis aera ee eee aaah eae eee 18 18 19

It is highly probable that the cause of the formation of more numer-
ous nodules in some cases is due not to the great numbers of bacteria
which are introduced into the soil but to the quantity of culture medium
introduced, which renders the soil solution a materially richer food for
the active growth of the nodule organisms. Thus, if a few bacteria
are brought into a favorable soil they will multiply rapidly, and it is
of no particular moment in such a case whether a very few or a large
number of bacteria are originally introduced. If, however, enough
culture is added so that the soil solution is appreciably improved in
food material for both plant and bacteria, then growth will be much
more active and nodule formation will be greater. On this hypothesis
the two results are not at all at variance, the effects produced depend-
ing on the soil conditions encountered by the bacteria and the crop.

The suggestion in a former bulletin@ that the slight varietal charac-
teristics exhibited by legume bacteria can be readily broken down by
cultivation on synthetic nitrogen-poor media seems to hold only for
bacteria isolated from plants physiologically related to the subsequent
hosts.”

A typical experiment is given below:

Number of nodules produced on two varieties of mung bean (Phaseolus viridissimus and
P. calcaratus) by cultures from various hosts.

[Ten plants in each of seven series. ]

Seal - | Bacteria
Bacteria Bacteria :
Variety of mung bean. from cow- | from soy Sr om P... | Withont
viridissi- | bacteria.
pea. bean. sane
IPhasecolushyalniGissinn Seeeer see ose ene eee ne eee * 0 77 0
Phaseolusicalcaratlisis. oases eee eee eee Cee ee | 0 0 88 0

* Fifteen plants in this series.

It may be added that the soil used was unsterilized garden soil,
naturally inoculated for our common bean, Phaseolus vulgaris, so that
the uninoculated check may be said to serve as a cross-inoculation with
these organisms also. This theory of varietal differences of nodule-

a4 Bul. 71, Bureau of Plant Industry, 1905, pp. 25-27.
b See Schneider, Ill. Agr. Exp. Sta. Bul. 29, 1894, p. 301.
100—vu1I

PLATE IX.

Bul. 100, Bureau of Plant Industry, U. S. Dept. of Agriculture.

Fic. 1.—POTS OF GARDEN PEAS, SHOWING THE EFFECT
OF AERATION ON GROWTH.

1.—Ordinary unglazed pot; surface of soil frequently stirred.
2.—Glazed pot; surface of soil paraffined and water intro-
duced through separatory funnel.

Fig. 2.—THE GARDEN PEAS ILLUSTRATED IN FIGURE 1, SHOW-
ING THE EFFECT OF AERATION ON NODULE FORMATION.

1.—Plant from unglazed, aerated pot. 2.—Plant from glazed pot
from which air was partially excluded.

i
2 oe

CONDITIONS AFFECTING LEGUME INOCULATION. 81

forming bacteria is closely in accord with field results reported by
various investigators, among whom perhaps Hopkins“ is best known
for his observations upon the cross-infection between sweet clover
and alfalfa and the absence of such cross-infection between many
other legumes.

EFFECT OF AERATION.

The aeration of soil for securing plentiful nodule formation is an
important if not a determining factor. The Ontario Agricultural
Experiment Station (Report for 1905, p. 39) reports a decided gain from
aeration in the case of a leguminous crop (peas) and no gain from the
aeration of a wheat crop. In the former case the result may be either
a direct one, affecting the activity of the nodule bacteria, or it may be
that because of the abnormal growth of the host plant the bacteria are
unable to penetrate the root. ?

Our own experiments upon the effect of aeration are in accord with
those quoted in regard to the legumes, and the following is typical: A
light sandy soil, moderately limed, was used and the lezume selected was
the garden pea. The aerated series was started in ordinary unglazed
4-inch pots, seedlings dipped in liquid culture when placed in position,
pots watered with a fine sprayer, using tap water. The surface of the
soil was frequently stirred. The nonaerated series was made up of an
equal number (6) of glazed 4-inch pots with bottoms plugged with
paraffined cotton and the tops covered with paraflined paper to reduce
aeration. A separatory funnel (shown in PI. IX, fig. 1) was thrust into
each of these pots to admit water for growing the peas, and after inocu-
lating as with the other series the seedlings were introduced through

“Til. Agr. Exp. Sta. Bul. 94, 1904, Nitrogen Bacteria and Legumes.

b Livingston (Bot. Gaz., X LI, 2, 1906, p. 143; see also Bureau of Soils Bul. No. 28)
reports a close relation between the growth of roots and tops in wheat, due to a dit-
ference of soil, which he explains as follows: ‘‘It would seem that the poor soil by
inhibiting branch growth and causing the enlargement of cortical cells may render
the root system unable to carry on an adequate amount of absorption for normal
growth.’ If this effect upon the cortical cells should be found to hold true with the
legumes, it might have a direct bearing upon the ability of the bacteria to penetrate
and form nodules. The enlargement of the cortical cell is regarded as a phenomenon
of age, and it is reported (Maria Dawson, Phil. Trans. Roy. Soc. London, Ser. B,
vol. 192 (1899), p. 24) that infection takes place most readily in quite young radicais.

Aside from the effect of root development upon nodule formation, there is a pos-
sible interaction resulting in some way in greater root development where inoculation
takes place. In many cases which have come to notice where inoculated plants had
shown a superior development of the root system, it seemed at least justifiable to
regard the inoculation as assisting in providing the conditions favoring a healthy
root growth. In Bulletin No. 237 of the Cornell Agricultural Experiment Station,
page 165, it is noted that where no nodules occur the roots of alfalfa are simpler and
not so ramifying as where nodules occur.

18270—No-. 100—07——6

82 MISCELLANEOUS PAPERS.

a hole in the parafiined paper. After a month’s time the roots of the
plants were examined, with the following results:

Nodules on plant No.—
Treatment.

See Plate VIII, figure 2, noting the difference in the plants in favor
of the noduled (aerated) plant.

ASSOCIATIVE ACTION OF BACTERIA.

Undoubtedly the pure cultures of nodule-forming bacteria are sub-
ject to contamination when planters, using convenient rather than bac-
teriological methods, prepare quantities sufficient to inoculate their
seed. Yet the purity of a culture immediately before it 1s applied to
seed or introduced into the soil of a cultivated field is unimportant,
provided there is present a sufficient number of virile nodule-forming —
bacteria. | |

Preliminary experiments at Washington some years ago indicated
that in the nitrogen-poor solution generally used the nodule-forming
bacteria would develop much more rapidly than other bacteria or con-
taminating yeasts-and molds. It might be expected that different
localities would have different contaminating forms, and during the past
year samples of cultures have been obtained from farmers in various
parts of the United States immediately before the seed or soil was
treated. Investigation of contaminating forms isolated from these
cultures shows that there are certain forms which inhibit the growth
of the nodule organism when both are grown for some time in the
usual nitrogen-poor solution.“ Using an extract of a favorable soil as
a culture medium, results very nearly parallel for the competing bac-
teria were secured, though one organism which resembles Bacillus cola
checked the growth of Pseudomonas radicicola in the synthetic medium
and not in the soil extract. - The relative virility of the competing cul-
tures at the time they begin their struggle is an exceedingly important
factor in determining which species of bacteria survives.

Extended experiments on the interaction of groups of bacteria in
various media must be carried on before it will be possible to deter-

«In view of this fact, the reason for our present method of distribution is apparent.
A relatively large amount of pure liquid culture used as a ‘‘starter’’ cuts down the
chances of ruining the farmer’s culture through the competition of contaminating
forms; the time required to fill the solution with the organisms is shortened, and, as
shown subsequently, the quicker the bacteria can be introduced into the soil and
make use of the soil solution as a culture medium the less becomes the danger from
competition.

100—vIII.

CONDITIONS AFFECTING LEGUME INOCULATION. 83

mine all of the conditions incident to success or failure in legume
inoculation.“ It is safe to assume, however, that the action of a bac-
terium in the soil is conditioned not only by the chemical and physical
characteristics of the soil solution at a particular time, but also, and
perhaps essentially, by the biologic conditions obtaining in that soil.

SUMMARY.

1. Lime is of decided benefit in obtaining successful inoculations
of legumes in some soils. These soils often show an acid reaction to
litmus.

9. Soil extracts serving as culture media often indicate the probable
success of inoculating a leguminous crop. This, however, may not
always hold true.

3. At least during the first season’s growth no general cross-
inoculation takes place. Bacteria from one host may, however, inocu-

late a physiologically related species.

4, Heavy inoculation by a pure culture increases nodule formation
if the soil solution is enriched by the excess of culture medium; how-
ever, in a favorable soil a light inoculation well distributed is as
effective.

5. Thorough aeration is favorable to nodule formation.

6. Whether in a synthetic medium or a natural soil solution, the
functions of a bacterium are influenced by the associative or competi-

tive action of the various groups of organisms with which it comes in

contact, as well as by the nature of the culture material.

a@See Maria Dawson, Phil. Trans. Roy. Soc. London, Ser. B, vol. 193 (1900), p. 65.
100—yiIr

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