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Bulletin No. 23. v. p. p. 76. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 
B. T. GALLONA^AY, Chief. 



SPOT DISEASE OF THE VIOLET. 



Al 1 1 fitii ml lUdld' 11. sp. 



»v 



P. H. DORSETT, 

A-ssoeiate, Divi>sioii < .f Venetahle Physiolocjy and Pathology. 



ISSIIEP NOVEMBKR 2S, 1900. 




WASHINGTON: 

() <) \' !•; R N M I', NT 1' K I \ r I N ( ; ( ) K l' UK. 
I 9 (J (J. 



DIVISION OF VEGETABLE PHYSIOLOGY AN1> rATHOLOGY, 



SCIENTIFIC STAFF. 

B. T. G\\.}.oyfKy, Chief of Dmsnon. 
Albert F. Woods, Amstant Chief. 

associates. 

Erwin F. Smith, Oscar Loew, 

Mertox B. Waite, W.\i. a. Orton, 

Newton B. Pierce, P'rxst A. Bessey, 

Herbert J. AVebber, Flora W. Patterson, 

M. A. Carleton, Hermann von Schrenk,* 

P. H. DoRSETT, Marcus L. Floyd.''' 

IN charge of laboratories. 

Albert F. Woods, Plant Physiology. 

Erwin F. Smith, Phmt Pathology. 

Newton B. Pierce, Pacific Coaxt. 

Herbert J. Webber, Plant Breeding. 

Oscar Loew,* Plant Nutrition and Fermeniaiion. 

1 Special agent in charge of studies of forest-tree diseases, cooperating with tlic Divisinn of Forestry, 
United States Department of Agriculture, and the Henry Shaw School of Botany, St. Louis, Mo. 

2 Detailed as tobacco expert, Division of Soils. 

•'In charge of the tobacco-fermentation investigations' of the Division of Soils. 



Bulletin No. 23. 



V. V. p. 7G. 



U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 
B. T. GALLOWAY, Chief. 



SPOT DISEASE OF THE VIOLET. 

(Alternaria violm n. sp. ) 



BV 



P. H. DORSETT, 

Associate, Division of Vegetable Physiology and Pathology. 



Issued November 28, 1900. 




WASHINGTON: 

O O V i; R N M E N T PRINTING O K K I C E . 
I 900. 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 
Division of Vegetable Physiology and Pathology, 

^Vaddngton, D. C, Amjicst 29, 1900. 
Sir: I respectfiill}' transmit herewith a paper b}- Mr. P. H. Dorsett, 
of this Division, giving the results of some investigations of a disease 
affecting cultivated violets and generally known as spot. There is not 
less than a million dollars' worth of violet flowers sold every year in 
the United States, and were it not for the disease in question the 
amount would doubtless be increased 20 per cent. The annual loss 
from the disease, therefore, represents probably a money value of fully 
1200,000. In view of the general interest in violet culture and the 
importance of the knowledge of a means of preventing the disease, I 
respectfully recommend the publication of the paper as Bulletin No. 
23 of this Division. 

Respectfully, B. T. Galloway, 

Chief of Division. 
Hon. James Wilson, 

Secretary of Agricultxire. 

3 



CONTENTS. 



Page, 

Introduction ' 

General appearance of the disease - 8 

Theories of the cause and treatment of the disease 9 

Weakness of the plants . .■ 9 

Improper soil conditions 10 

Improper conditions furnished the plants during the growing and flower- 
ing season 10 

Fungous nature of the disease 10 

Conditions favoring the development and spread of the disease 13 

Susceptiliility of varieties - 1"* 

Preventive measures 1^ 

Explanation of plates 1^ 

5 



ILLUSTRATIONS. 



Page. 

Plate I. Healthy and diseased leaves of ]\larie Louise violets 16 

II. Young plants of Marie Louise violet from the cutting bed showing 

spot on their leaves 16 

III. A healthy and a naturally infected ^larie Louise plant 16 

IV. A healthy (control) and an artificially infected Marie Louise plant.. 16 
Y. Plate cultures of Alternaria violx and mycelium and spores from a 

diseased leaf 16 

VI. Development and germination of spores of Alternaria violse and pure 

culture upon Lima bean 16 

Vn. Diseased and healthy leaves of California violet 16 

6 



SPOT DISEASE OF THE VIOLET. 



INTRODUCTION. 



The subject of this paper is one of the most widespread and destruc- 
tive maladies known to attack the violet. The disease has been dis- 
cussed in the florists' journals under a variety of names, such as leaf 
spot, leaf rust, leaf blight, smallpox, etc. More commonly, however, 
the trouble is known as the " violet disease," growers not generally 
recognizing the fact that there is more than one malad}^ attacking the 
violet. The disease occurs throughout this countr}' wherever the violet 
is grown, and is probably of American origin. The cultivation of the 
violet has been abandoned in many sections of the country on account 
of its ravages, while in others it has become necessary to adopt new 
methods of handling the plants during the growing season. 

Five or six years ago, for example, 50,000 to 75,000 square feet of 
glass in the vicinity of Alexandria, Va., were devoted to the cultiva- 
tion of this crop, but on account of the disease the industry has been 
practically abandoned. A large grower near Boston, Mass., was 
forced, a few years ago, to abandon growing stock plants at his place 
on account of this trouble. He had to have them grown for him dur- 
ing the summer, at considerable expense, in localities that were free 
or comparatively free from the disease. After transferring these 
plants to his place in the fall and setting them in the houses he expe- 
rienced little or no difficulty in keeping them healthy during the 
remainder of the season. Many other instances of the destructive 
nature of this disease could be cited. 

The large amount of florists' litcn-ature relating to this subject when 
collected and condensed was found by the writer to contain only a con- 
fused mass of contradictory opinions regarding both the cause and 
treatment of the disease. This is not strange to one familiar with the 
violet. All growers know the violet to be variable, seldom if ever 
behaving any two seasons alike. Practical growers recognize the fact 
that methods of handling the plants followed with little disease and 
good results during one season may, though rigidly adhered to, result 
in disease and failure the next. It is also a well-known fact that gi'ow- 

7 



8 

e.rs in the same section and in close proximity to one another often prac- 
tice widel}^ different methods in growing this crop, and 3'et the results 
obtained are practicall}^ the same. A novice in violet growing may 
have little or no difficulty the first few years in growing good flowers. 
After this, however, his troubles usually begin and failure more often 
than success crowns his efforts. Unless he is possessed of peculiar 
abilities and a determination to succeed a few years of reverses are suf- 
ficient to cause him to abandon the culture of violets and turn his 
attention to some other industry where the chances of success are at 
least equal to those of failure. 

GENERAL APPEARANCE OF THE DISEASE. 

Spot disease of the violet {AUernaria molce) attacks the plants at any 
stage of their growth from the small unrooted cutting in the cutting 
bed to the mature plant in full flower. (See Pis. II, III, and IV.) 
Plants that are making a vigorous, rapid, but soft or succulent growth 
are most subject to the disease. The disease may occur on any por- 
tion of the plant above ground, but causes the greatest amoimt of loss 
when present upon the foliage. Its first appearance upon the leaves 
is characterized by small, definite, usualh' circular, greenish or yel- 
lowish white spots, resembling very much the ))ite or sting of an insect. 
They var}' in size from dots scarcely perceptible to the unaided 63^6 to 
spots a thirty- second of an inch or more in diameter. The light- 
colored central portion or point of infection is surrounded by a narrow 
ring of discolored tissue, usually black or very dark brown at first, but 
changing to a lighter shade as the spots grow older. (Pis. II, III, 
IV.) As the spot develops the central portion remains unchanged in 
appearance, while the tissues immediately surrounding it, either to one 
side or more frequently in a circle, become diseased by the ramify- 
ing growth of the mycelium of the fungus through this portion of the 
leaf. This usuall}- takes place within a few hours after infection. 
The freshly diseased portion of the leaf at first presents a water- 
logged appearance, frequently being semi-transparent, and is lighter 
in color than the adjacent healthy tissue. The diseased portion around 
the central point of infection in a few days fades or bleaches to a yel- 
lowish or grayish white, sometimes to a pure white, the time depend- 
ing somewhat upon the conditions of the weather. The development 
of the disease may stop at this point and the plants apparentlj^ entirely 
recover from its effects; in which event the diseased portions of the 
leaves after a few days separate from the healthy tissue and fall out, 
leaving the leaves full of holes. More frequently, however, the 
disease continues to develop in the parts of the leaf adjoining or sur- 
rounding those alreadj^ diseased. These freshly diseased areas in turn 
pass through the same changes as the parts previously attacked. 
Unless checked by some means the disease continues to spread in this 



9 

way until the entire leaf is destroyed. It is seldom, however, that a 
single spot upon a leaf develops to this extent. More frequentl}' the 
leaf is attacked at a number of different points (Pis. I, 11, III, IV), 
and as the disease progresses the spots become larger and one or more 
of them coalesce, forming large irregular areas or blotches upon the 
leaf. (Pis. I, II.) A well-developed spot of this disease therefore 
shows a light-colored central portion, the point of infection, partly or 
wholly surrounded liy alternate rings of dark and light colored tissue, 
the lighter colored portions as a rule being ver}' much broader and 
more conspicuous than the darker. (Pis. I, II.) The majority of these 
spots are usuall}'^ free from fungous spores exc(?pt under conditions 
peculiarly favorable to their development. Spores are produced, 
however, in great abundance upon most of them, especially upon the 
central or older portions of the spots, after the leaves have been placed 
in a saturated atmosphere for from twenty-four to forty-eight hours. 
It is frequently the case that spores are produced in sufficient numbers 
to be discernible by the unaided eye, but usually the aid of a hand lens 
or a microscope is necessarj^ to determine their presence. The spores 
are borne in chains on dark brownish hypha? that rise from the dis- 
eased surface. PI. V, fig. 2, shows a photomicrograph of some of the 
mycelium and spores of this fungus taken from a diseased spot in a 
living leaf. The spores break from their attachment and separate 
from each other easily, and being very small and light they are car- 
ried around liy currents of air and finally settle upon other leaves. 

THEORIES AS TO THE CAUSE AND TREATMENT OF THE DISEASE. 

Perhaps no subject relating to floriculture has received more atten- 
tion in the floricultural and horticultural journals during the past 
eight or ten years than the disease in question. The most varied 
opinions have been expressed in regard to it, and the explanations 
advanced as to its cause and the possible course of treatment are 
numerous. Some of the more important of these hypotheses are 
given here. 

WEAKNESS OF THE PLANTS. 

Some writers claim that the plants are of necessity weakened by 
being forced during the winter into heavy flower production, and 
that the taking of cuttings from such plants, and the rooting and forc- 
ing of them in the same way from year to year has resulted in pro- 
ducing a weak strain peculiarly susceptible to injury of all kinds. 
They reconnnond fall propagation to secure strong, vigorous, health}^ 
wood before the plants are weakened by flowering. The cuttings, 
after being rooted in clean, sharp sand, are transplanted into thumb-pots 
or into flats and carried through the winter in a house or in frames, 
where the temperature is kept as low as possible, not allowing the 



10 

plants to freeze, however. By this treatment the plants are given a 
rest, which is believed b}- many to be necessary to strong, vigorous 
growth. While growers generallj" admit that slightly better results 
are usuall}" obtained b}' this treatment than b}- the one generally prac- 
ticed, the}' are, as a rule, of the opinion that the benefits derived will 
not justify the expense necessary to carry the young plants through 
the winter in good condition for spring planting. This is an impor- 
tant problem, the practical solution of which would no doubt prove of 
great value to all interested in the cultivation of the violet. We have 
this work under way at the present time, and hope in a few years to 
obtain some interesting results. 

IMPROPER SOIL CONDITIONS. 

Other writers claim that the disease is due to improper soil condi- 
tions. The soil is either too heav}^ or too light in texture, and as a 
consequence holds, or gives up. too much or too little moisture, or con- 
tains too much or too little plant food. They advise selecting soil 
suited in every wa}^ to the best growth and development of the plants. 

Since good soil is one of the prime factors governing strong, vigor- 
ous, health}' plant growth, their advice is good, but extremely difficult 
to follow. The question of securing proper soil is one of the most 
perplexing with which the grower has to contend, requiring judgment 
that can be gained only by many years of practical experience. 

IMPROPER CONDITIONS FURNISHED THE PLANTS DURING THE GROWING AND FLOWERING 

SEASON. 

Still others attribute the disease to improper methods employed 
during the growth of the plants, such as growing them in the open 
field, where they are exposed to drought, rains, dews, and the direct 
rays of the sun during the summer, and lack of attention to properly 
heating, ventilating, and fumigating the houses and to cultivating, 
watering, and cleaning the plants. As a remedy they propose fur- 
nishing the necessary conditions for vigorous, healthy plant growth 
at all times. This is a good doctrine, but begs the question. 

FUNGOUS NATURE OF THE DISEASE. 

Over four years ago the writer succeeded in producing upon violet 
leaves spots that were in every way identical with those above described 
by spraying the leaves with distilled water to which spores of the fun- 
gus Alternaria vioim had been added. Since that time he has proved 
by nmuerous laboratory and greenhouse experiments (details of which 
will appear in the following pages) that the so-called ''spot disease" 
of the violet is unquestionably due to the attacks of this fungus. 
Other fungi, Cercosjxjra viohe Sacc, F/iyUostictavwhv Besm.. Sepforia 
violce Wesid., etc., are known to attack the violet, producing upon the 



11 

leaves spots very similar in outline and appearance to those caused 
by xllternaria vlolm (with which they are often confused), but in the 
writer's experience in the study of the violet and its diseases he does 
not recall a single instance where these fungi have come to his atten- 
tion as causing any serious trouble. It is possible, however, for them 
to do considerable damage under conditions peculiarly favorable to 
their development. 

Ninety-live per cent of all the specimens of the .so-called violet disease 
received at the Division laboratory during the past four or five years 
were found, upon careful microscopical examination, to contain spores 
of the particular fungus mentioned.' 

The fungus was isolated by agar poured cultures in Petri dishes, and 
comparatively little difficulty was experienced in securing pure cultures 
for inoculation experiments. The growth and development of the fun- 
gus on artificial media is, as a rule, quite rapid, normally producing 
spores in from four to six days after the sowing of the spores or the 
transferring of a single germinating spore from one plate culture to 

another. 

The growth of the fungus in agar is normally in concentric rings, 
each ring marking the amount of growth made in twenty-four houra 
(PI. V, fig. 1). The color of the fungus growing on agar before spore 
formation is grayish white (PI. V, fig. 3). Spore production begins 
at the center on the older growth, and gradually extends outward, 
until the entire surface of the colony is covered with a dense mass of 
olivaceous spores. The fungus grows well on other culture media, 
especially young lima bean pods (PI. VI, fig. 18). 

The first inoculation experiment with Alternaria molce was made 
February 12, 1896. Two plants of Marie Louise violet, in 4-inch 
pots, were removed from the Department greenhouse to the labora- 
tory. They were quite uniform in size and, as far as could be ascer- 
tained by observation, entirely free from disease. Plant No. 1 was 
sprayed with sterile distilled water and placed under a bell jar in a sat- 

^ SCIENTIFIC DESCRIPTION OF THE FUNGUS. 

Alternaria violse Galloway and Dorsett. 

Amphigenous, but especially epiphyllous, olivaceous, velutinous, on light-colored 
subcircular definitely limited spots 2-4 mm. in diameter, extending into arid 
patches 10-12 mm. in diameter, which show one or more dark concentric lines; 
spore-bearing hyph?e fasciculate, erect, pale olivaceous, septate, simple, 4 l)y 25-30 a; 
conidia borne at or near tips of the hyphte, catenulate, clavately Hask-shapcd, 
muriform, strongly conHtricted at the septa, which are variable in number, oliva- 
ceous, 10-17 l)y 40-60 /.i exclusive of istlnnus, which is 3-5 by 3-25 //. 

Dr. Gino Pollacci has described and figured (Atti del K. Inst. Bot. dell'Univ. di 
Pavia (Laboratorio crittogamico) Ser. II, Vol. V, pp. 1-2, PI. VII, figs. 1-5, 1897) 
a spot disease of violet occurring in Italy which is due to a fungus which he names 
}f(icnjspnriiiiri rlolir. If his description and (h-awingsare correct the two diseases are 
quite distinct. 



12 

urated atmosphere, where it was kept. Plant No. 2 was sprayed with 
sterile distilled water in which spores from a pure culture of Alter- 
naria molce had been sown, and was then placed under the same con- 
ditions as plant No. 1. The temperature of the laboratory at the 
beginning of the experiment — 3.30 p. m. — was about 80- F. The fol- 
lowing- notes, made during the progress of the experiment, are descrip- 
tive of the results obtained: 

February 14, 1896, 9.30 a. m. Plant 1 apparently in a perfectly healthy condi- 
tion, leaves covered with moisture, but showing no ill effects from the spraying or 
from being kept in a saturated atmosphere. Plant 2 liadly diseased, nearly every 
leaf showing one or more spots of infection, which are in every particular identical 
with the first stages of the disease as naturally produced. 

February 15, 1896, 9.30 a. m. Plant 1 still remains healthy and apparently unin- 
jured by the treatment. On plant 2 the disease is progressing rapidly. There is a 
peculiarly disagreeable odor present when the bell jar is removed that is not 
noticeable under the same conditions with plant 1. This odor, so far as I am able 
to judge, is identical with that noticed with plants suffering from an attack of the 
disease under normal conditions. This odor is one of the characteristics of the dis- 
ease, and its presence in the house, frame, or field is usually the first intimation the 
grower has of the presence of the disease among his plants. 

February 19, 1896. Plant 1 still healthy and apparently in good condition. The 
spots on plant 2 are a little further developed and resemble more closely those 
produced under natural conditions. 

A striking example of the results obtained b}' artificial inoculations 
of violets with this fungus is shown in PI. IV. The two plants shown 
in this photograph received the same treatment as that given the two 
plants in the experiment described. The plants were sprayed at 3.30 
p. m., August 26, 1896, and examined first at 2.30 p. m., August 27, 
1896, just twenty-three hours after treatment. At this time plant 
No. 1 appeared free from disease, and showed no ill effects whatever 
from the treatment. On the contrary each leaf of plant No. 2, with 
one or two exceptions, showed from 1 to 30 or more spots of the dis- 
ease, which were in every way identical with those produced on plant 
No. 2 in the previous experiment. 

The plants were photographed August 31, 1896. At this date plant 
No. 1 was apparently free from disease, while the disease on plant 
No. 2 had made considerable progress and the spots w^ere gradually 
assuming the normal colorings which are characteristic of this disease. 

In these spots thus produced a careful microscopic examination 
demonstrated the presence of the mycelium of the fungus, and subse- 
quent observation showed that the fungus pushed through to the 
surface of the spots and fruited, whenever the leaf was put under a 
bell jar in moist air, exactly as it did on spots occurring naturally. 
The disease was again produced in health}- plants by inoculation with 
the spores- thus formed. 

That the spots produced upon violet leaves by artificial inoculations 
with spores of Alternaria violce closely resemble those occurring natu- 



13 

rally can be readily determined by comparing PL III, which is a photo- 
graph of a naturally diseased and a healthy plant from greenhouses 
at Garrett Park, Md., December 18, 1897, with PI. IV, which is a 
photograph of a healthy and an artificially infected plant. The simi- 
larity of the spots is, however, more strikingly shown in PI. I. Fig. 1 
is a healthy leaf; fig. 2 is a diseased leaf from a plant naturally infected 
with the disease, while leaves 3 and 1 were taken from the diseased 
plant shown in PI. IV, which was artificially infected with the disease. 

Spores of the fungus Alternaria violw sown in water in a van Tieg- 
hem cell and kept at a temperature of 65° to 80° F. germinate readily 
in from one and a half to three hours. Fig. 9, PI. VI, is a camera 
lucida drawing of a group of spores that were sown in distilled water 
and placed in a van Tieghem cell at 10 a. m., January 15, 1898. The 
dotted lines at right angles to several of the germ tubes mark the 
amount of growth made by them between the time of sowing and the 
time noted; all subsequent growth and the production of all germ 
tubes not marked with a dotted line occurred between 11.55 a. m. and 
2.10 p. m. the same day. Figs. 1 to 6 show a camera lucida drawing of 
a group of Alternaria spores in distilled water just previous to being- 
placed in a van Tieghem cell, and figs. 7 and 8, two spores in the same 
sowing, nineteen hours later. Figs. 11, 13, and 11: show spores that 
were sown in distilled water in a van Tieghem cell at 10.20 a. m., 
August 19, 1898, at which time they showed no signs of germinating. 
Four hours later, however, at 2.20 p. m., the time at which the draw- 
ings were made, the number of germ tubes had developed as indicated. 
Fig. 12 is a second drawing of fig. 11, made twenty minutes later. 
Fig. 10 is a camera lucida drawing of two spores from four to six hours 
after being placed in distilled water. Figs. 15, 16, and 17 show the 
chain formation of spores and their attachment to the mycelium. 
This drawing was made from a pure plate culture of the fungus. 

Numerous greenhouse and laboratory experiments under strict con- 
trol conditions have confirmed these results, and show that spot disease 
of the violet is due directly to the attack of the parasitic fungus 
Altermiria violce, and not to any of the other causes suggested. Indi- 
rectly, however, other conditions may have their efi'ect. Any one or 
a combination of all of the conditions included in the various theories 
advanced may cause the plants to become susceptible to the attacks of 
the fungus. 

CONDITIONS FAVORING THE DEVELOPMENT AND SPREAD OF THE DISEASE. 

The conditions favoring the development and spread of the fungus 
may be considered under two heads, viz, natural conditions and arti- 
ficial conditions. 

Among natural conditions those of the damp, warm, cloudy weather 
of the summer season are the most diflicult to modify or control. 



14 

Conditions of this nature are almost invariably present during the 
months of August and September. The da^^s are long and usually 
hot and dry, followed, as a rule, by cool, moist nights. The plants at 
this time are subjected to extreme changes, viz, from the hot, dry 
atmosphere during the da}", which frequently causes them to become 
wilted and remain so for several hours, to the cool, moist atmosphere of 
the night, which causes them to become excessiv^ely turgid. Conditions 
of this kind induce a I'apid, weak, soft, or succulent growth of the plants 
which is particularlj' subject to disease and at the same time favors the 
germination and development of the spores of the fungus. It is at 
this season of the year, as a rule, that the spot disease is most abun- 
dant and destructive. This is the time for great vigilance, and every 
condition influencing plant growth must be made as favorable as pos- 
sible to a hardy, health}^ growth which will be able to withstand the 
attacks of disease. The grower who is able to accomplish this and 
tide his plants over this critical period of their growth in a compara- 
tivel}' healthy condition is fortunate, and, as a rule, has little to fear 
from the disease during the remainder of the season. 

Artificial conditions include those wholly or in part under the con- 
trol of the grower. They are too often neglected, resulting as a rule 
in disease and consequent loss and discouragement. They may be 
enumerated as follows: 

(1) Not keeping the houses or frames clean, fresh, and sweet by 
frequently repairing and painting them and b}^ removing and destroj'- 
ing rubbish of all kinds as soon as it appears. 

(2) Not keeping the plants clean and in the best possible growing 
condition at all times. 

(3) Not selecting stock from strong, vigorovis plants that have been 
entireh' free from disease. 

(4) Not being careful to select only strong, vigorous, healthy stock 
from the cutting bed for planting in the spring. 

(5) Not giving the proper attention to the selection and preparation 
of the soil, to the date and method of planting, and to the care and 
cultivation of the plants during the growing season. 

(6) Not giving due consideration to the several varieties and their 
adaptability to the soil and location in which they are to be grown. 

SUSCEPTIBILITY OF VARIETIES. 

While the susceptibilit}" of the plant to disease depends largel}' upon 
the way in which it has been grown, still, as a whole, some varieties 
are more susceptible than others; Marie Louise, for example, even 
under conditions most favorable to growth, is more subject to injuiy 
from spot than is Lady Hume Campbell. The former variety can be 
grown to perfection only under the most favorable conditions, but 
when thus grown it has no equal for size, color, and excellency of flower. 
The hardier, more resistant, and more prolific variety Campbell stands 



15 

next to Marie Louise in qualit}" of flowers, lacking onl}' the deep rich 
color of the latter. The single varieties are as a rule more resistant 
than the double, though occasionally they are seriousl}" afi'ected. 
(Plate VII.) 

PREVENTIVE MEASURES. 

So far as we are aware there is at present no effective remedy for 
this disease when it has gained a foothold. The principal fungicides 
in common use for the prevention and check of plant diseases have 
frequently been tried for this trouble, but with varying results. The 
experiments of the Division in spraying violets with some of the 
more important of these, among them Bordeaux mixture and ammoni- 
acal solution of copper carbonate, seem to show that they possess little 
or no value in preventing the disease, while on the other hand they 
render the foliage worthless for bunching with the flowers, and thus 
occasion considerable loss and inconvenience. From the writer's 
experience and that of many others it would seem that the solution 
of this problem of controlling the disease lies in preventing it by 
giving careful attention to the production of vigorous, healthy, plant 
growth rather than in attempting to check the trouble after it has 
once gained a foothold. 

The successful growing of violets free from disease and the pro- 
duction of flowers of the best quality are governed by a number of 
factors which must be kept in mind. The principal rules which should 
govern the grower are the following: 

(1) Study carefully the behavior of the plants under the varying 
conditions surrounding them. Endeavor by modifying these condi- 
tions, when necessar}", to secure plants of ideal development. Set the 
standard of excellence high and be satisfied with nothing short of its 
attainment. 

(2) Grow the plants during the entire season where the}" can be 
given the conditions necessary for making a vigorous, healthy growth, 
and where they can be protected at all times from conditions likely to 
induce disease. 

(3) Keep the houses or frames clean, sweet, and in perfect condition 
for growing healthy plants, by repairing and painting them when nec- 
essary, and by removing and destro3dng all rubbish likely to harbor 
vermin or disease. 

(4) Propagate only from healthy, vigorous stock (;f known parent- 
age at the season most favorable to the plants. 

(5) Select each spring none })ut perfectly healthy, vigorous plants 
from the rooted cuttings for planting into the houses or frames. Old 
plants are sometimes carried over, and occasionally yield a large crop 
of flowers. They are not as reliable as the young plants, however, and 
are much more liable to all kinds of disease. The best growei's rarely 
use them if it is possible to secur(> strong, health}' young plants for 
spring or early summer planting. 



16 

(6) Keep the plants clean of yellow, dead, or dying leaves, being 
careful to destroy them after removing them from the plants, 

(7) Keep the plants free from insects and other animal pests. 

(8) Give careful attention to ventilating, heating, and shading the 
houses or frames and to watering, cleaning, and cultivating the plants. 

(9) Renew the soil in the beds each season before setting in the yovmg 
plants by removing from eight to twelve inches of the surface soil 
and replacing it with that freshh^ prepared, 

(10) Set the young plants early in the spring in the beds where the}^ 
are to remain during the season, so that they may get well estal^lished 
before the hot. dry weather of summer makes its appearance. 

Careful attention given to the above directions for a number of 
years will, it is believed, result in the production of a strain of plants 
that are not only practicalh' disease resistant, but are also ideal as 
regards regularity and symmetry of growth, length, and strength of 
flower stems, and 3'ield, size, substance, and qualit}' of flowers pro- 
duced. 

EXPLAXATIOX OF PLATES. 

Plate I. Healthy and diseased leaves of Marie Louise violet. (Natural size. ) Fig. 1, 
healthy leaf. Fig. 2, naturally infected leaf. Figs. 3 and 4, artificially 
infected leaves from the diseased plant shown in Plate lY. 
II. Young plants of 3Iarie Louise violet from the cutting bed, showing spot 
on the leaves. 

III. Fig. 1, healthy plant of ^larie Louise violet for comparison. Fig. 2, dis- 

eased plant (natural infection). 

IV. Fig. 1, healthy plant of Marie Louise violet (control). Fig. 2, diseased 

plant (artificial infection). 
Y. Fig. 1, growth of the fungus in eleven days from a single spore <>n an 
agar plate. Fig. 2, photomicrograph of mycelium and spores of Alter- 
narki violee from violet leaves. Fig. 3, pure plate culture of Alfemaria 
riola: 
YI. Figs. 1 to 6, inclusive, show spores as they appear when brushed from a 
diseased spot. Figs. 7 and 8, some of the same spores after nineteen 
hours in distilled water in a van Tieghem cell. Fig. 9, a group of ger- 
minating spores. The length of the germ tubes at the time of the first 
examination is indicated by the dotted lines, and time marked; all 
subsequent growth of these tubes occurred, and all unmarked tubes 
developed, between the time marked and 2.10 p. m. Fig. 10, two con- 
nected spores germinating at several points after l)eing about four hours 
in distilled water. Fig. 11, germinating spore. Fig. 12, the same spore 
twenty minutes later. Figs. 13 and 14, germinating spores. Figs. 15, 16, 
and 17, spores produced on agar, showing manner of attachment to 
mycelium and chain formation of spores. Fig. 18, pure culture of Alter- 
naria rioliv on sterilized lima bean. The darker part of the culture is 
thickly covered with spores; the white marginal portions are young grow- 
ing mycelium. 
VII. Fig. 1, healthy leaf <if California violet. Figs. 2 and 3, diseased leaves of 
California violet, 

o 



BUL. 23, DIV. VEG. PHYS. & PATH., U. S. DEPT. OF AGRICULTURE. 



PLATE 




D. Q. PASSMORE. .\ Horn. X (-...Lilh. Riillim""- 

HEALTHY AND DISEASED LEAVES OF MARIE LOUISE VIOLET. 



Bui. 23, D V. Veg Fhys, &c Path. U. S. Dept. o' Agriculture. 



Plate II. 



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c 
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o 



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o 

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CO 



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Bui. 23, Div. Veg. Phys. 8i Path., U. S. Dept. of Agriculture. 



Plate 11 




Bui. 23, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



Plate IV. 




Bui. 23, Div, Veg. Phys. & Path., U. S. Dept. of Agriculture. 



Plate V. 




Plate Culture of Alternaria viol^, and Mycelium and Spores from a Diseased 

Leaf. 



Bui. 23, Div Veg. Phys. & Path., U. S. DeDt. of Agriculture. 



Plate VI. 




Development and Germination of Spores of Alternaria viol/E and Pure Culture 

UPON Lima Bean. 



Bui. 23, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



Plate VII 




Diseased and Healthy Leaves of California Violet. 



Bulletin No. 24. v p. p.— 77. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 
B. T. GALLOWAY, Chief. 



THE BASIS FOR THE IMPROVEMENT 
OF AMERICAN WHEATS. 



BY 



MARK ALFRED CARLETON, 
Cerealist, Division of Vegetable Physiology and Pathology. 




Issued December 10, 1900. 




WASHINGTON : 

GOVERNMENT PRINTING OFFICE. 
I 900. 



DITISION OF TEGETABLE PHTSIOLOGT AND PATHOLOGY. 



SCIEXTIFIC STAFF. 

B. T. Galloway, Chief of Division. 
Albert F. Woods, Assistant Chief. 

associates. 

Erwin F. Smith, Oscar Loew, 

Merton B. Waite, Wm. A. Ortox, 

Newton B. Pierce, Ernst A. Bessey, 

Herbert J. Webber, Flora W. Patterson, 

M. A. Carleton, Hermann von Schrenk,^ 

P. H. DoRSETT, . Marcus L. Floyd.'* 

^ IN CHARGE OF LABORATORIES. 

Albert F. Woods, Plant Physiology. 

Erwin F. Smith, Plant Pathology. 

Newton B. Pierce, Pacific Coast. 

Herbert J. Webber, Plant Breeding. 

Oscar Loew,^ Plant Nutrition and Fermentation. 

1 Special agent in charge of studies of forest tree diseases, cooperating with the Division of Forestry, 
United States Department of Agriculture, and the Henry Shaw School of Botany, St. Louis, Mo. 

2 Detailed as tobacco expert, Division of Soils. 

s In charge of the tobacco fermentation investigations of the Division of Soils. 



BUL. 24. PIV. VEG. PHYS. & PATH., U. S. DEPT. OF AGR. 



FRONTISPIECE. 




AHCEMftCO e-AUIMORH 



Bulletin No. 24. V. P. P.-77. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 
B. T. OALLOWAV, Chief. 



THE BASIS FOR THE IMPROVEMENT 
OF AMERICAiN WHEATS. 



BY 



MARK ALFRED CARLETON, 
Cerealist, Division of Vegetable Physiology and Pathology. 



Issued December io, 1900. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
I 900. 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 
Division of Vegetable Physiology and Pathology, 

Washington, D. C, July 19, 1900. 
Sir: I have the honor to transmit herewith, and to recommend for 
publication as Bulletin No. 24 of this Division, the manuscript of a 
paper by Mr. M. A. Carleton, on The Basis for the Improvement of 
American Wheats. During the past ten years this Division has had 
under investigation a number of problems connected with cereal pro- 
duction, and in order to carry on this work intelligently it has been 
necessary to make a careful study of the wheat industry generally. 
To this end a thorough survey of the field has been made, and the 
results are brought together here. The bulletin will prove especially 
valuable as showing the lines along which further work must be 
carried on. Part of this work is already under way, and other lines 
will be taken up as rapidly as the means at hand will permit. 
Respectfully, 

B. T. Galloway, 

Chief of Division. 
Hon. James Wilson, 

SeOi etary of Agriculture. 

8 



CONTENTS. 

Page. 

Introduction 7 

Personal exijlorations 9 

Characteristics and needs of the several wheat districts of the United States .. .9 

General needs of all the districts - 10 

Yielding power 10 

Early maturity 11 

Soft wheat district - 12 

Semihard winter wheat district 13 

Southern wheat district 14 

Hard spring wheat district 15 

Hard winter wheat district 17 

Durum wheat district - 18 

Irrigated wheat district 20 

White wheat district 22 

Sources for desirable qualities - - 25 

Characteristics of botanic groups of wheat 26 

Common bread wheats ( Triticum valgare) 26 

Club or square head wheats ( T. compactum) 28 

Poulard wheats ( T. turgidum ) 29 

Durum wheats ( T. durum) 30 

Polish wheats ( T. polonicum) - - - 32 

Spelt (T. spelta) ---- 33 

Emmer ( T. dicoccum) 34 

Einkorn ( T. monococcum ) 35 

Geographic groups of wheats - - - 36 

Improvements accomplished - 37 

Introduction of new varieties 38 

Work of the Department 40 

Wheat breeding 63 

Improvement by selection 64 

Improvement by hybridization 69 

Summary 77 

5 



ILLUSTRATIOXS. 



PLATES. 



Pasre. 



Fkontispiece. Map showing the distriljution by districts of the different nat- 
ural groups of ^Yheat varieties in the United States. 

Plate I. Wheat field near jNIount Vernon, Va 12 

II. Fig. 1, Wheat fields of the Red River Valley near Grand Forks, 
N. Dak. Fig. 2, Self-binders at ^\'oi-k near Grand Forks, 
N. Dak 16 

III. Fig. 1, Field of wheat on "Tule" lands near Stockton, Cal. 

Fig. 2, Steam combined harvester-thresher harvesting on 
"Tule" lands near Stockton, Cal 22 

IV. Fig. 1, Bags of wheat just harvested on the Bidwell estate, Chico, 

Cal. Fig. 2, Wheat field near Tehama, Cal 22 

V. Fig. 1, Harvesting with the combined harvester-thresher near 
Walla Walla, AVash. Fig. 2, Wheat fields before and after 
harvesting, near Walla AValla, Wash 24 

VI. Fig. 1, Combined harvester-thresher at work near Walla Walla, 
Wash. Fig. 2, Harvesting with the wide-cut binder near 

Colfax, Wash 28 

VII. Spelts and Emkorns in exi^erimental plats at Garrett Park, Md. 34 
VIII. Fig. 1, Group of Russian wheats in experimental plats at Garrett 
Park, Md. Fig. 2, Experimental wheat plats at Garrett Park, 
Md. , showing earliness of King's Jubilee 62 

IX. Hybrid wheats. Early Arcadian and Diamond Grit, shown by the 

side of the parent varieties 72 

X. A comjjosite cross by the Gartons, showing samples of the prog- 
eny of the last cross 74 

TEXT FIGURES. 

Fig. 1. Diagram showing pedigree of Early Genesee Giant Wheat 71 

2. Diagram showing pedigree of one of the Gartons' hybrid wheats 74 

3. Diagram showing pedigree of one of the Gartons' hybrid wheats 75 

4. Diagram showing pedigree of one of Farrer's hybrid wheats 76 

5. Diagram showing hypothetical cross of wheat and spelt 76 

6 



THE BASIS FOR THE IMPROVEMENT OF AMERICAN 

WHEATS. 



INTRODUCTION. 

In 1894 the Division of Vegetable Physiology and Pathology began 
experiments on an extensive scale to test the comparative rust resist- 
ance of different varieties of cereals, especially wheat. This work was 
carried on for three seasons at Garrett Park, Md., Salina, Kans., and 
Manhattan, Kans., respectively. An account of the results of this 
work has already been published/ so that it is unnecessary to refer to 
them in detail here. Suffice it to say that in the course of the work it 
became apparent that constant rust resistance is not to be obtained 
among the ordinary bread wheats known at present, though on an 
average a few such varieties are fairly resistant during a long period 
of years. By the results obtained it was rendered highly probable 
that this quality must be bred into a variety either by rigid selection 
of the most resistant individuals of that variety or by crossing with 
resistant varieties of other wheat groups and selecting from the result- 
ant progeny such types as combine in the highest degree the usual 
qualities of the bread-wheat group with that of rust resistance. 

It was found, moreover, that in regard to other qualities than rust 
resistance it is not possible to obtain varieties which even approximate 
perfection, and especially is it rarely, if ever, true that many desara])le 
qualities are found in the same variety. However rust resistant a cer- 
tain variety may be, it will usually l)c found lacking in some other 
^sential quality, and manifestly the most perfect rust resistance is 
of no consequence if other essential qualities are absent. As a rule 
the wheats that are most highly resistant to orange leaf I'ust^ are not 
varieties of the common bread-wheat group {Trlttcxiii vi(lg((r<') at all. 
though it by no means follows that they can not be used in bread 
making. At the same time some of the most valuable sorts for bread 
Hour, including a number of Russian varieties, rust very badly in 
certain seasons. Occasionally good qualities may neutralize bad ones 

__^ ^ ^ • — ■ ■ 

'Cereal Rusts of the United States, Bnl. No. 16, Division of Vegetalile Pliysioiogy 
and Tathology, U. S. Department of Agr., lS!)i>, by M. A. Carleton. 

"■"For descriptions of the two wheat rusts of this country and illustrations of their 
differences see Bui. No. Ki "I" this Division, a))ove referred to. 



8 

in the same variety. For example, a variety may be very susceptible 
to rust when attacked, but usually be able to escape it by virtue of its 
quality of early maturity. 

Consideration of such facts linally led to the determination to study 
thoroughly wheat varieties themselves in all their relations, and not 
simply wheat diseases. Such a study of course naturally presupposes 
the investigation of all associated problems, such as drought resistance, 
early maturity, yielding power, and other matters of great economic 
interest. The different phases of the subject of wheat culture in its 
broadest sense are so intimately connected that no one of them can be 
intelligently studied separate and apart from the others. 

During the iirst season (1895) of the investigations above mentioned 
about one hundred crosses were attempted with wheat varieties (besides 
a number with varieties of oats), mainly to determine the facility with 
which hybrids might be produced by crossing varieties of quite differ- 
ent groups. One-third of these crosses resulted successfully, unless a 
few of them ma}' possibly have resulted from accidental pollination. 
Some of them were readily effected between varieties of common 
wheat {Triticum vidgare) and the durums {T, duTimi)^ as well as 
between varieties of each of these groups and the poulards {T. turgi- 
dum). All the resulting hybrids were planted, but, the weather con- 
ditions of the following season being unusuallj^ severe, these and many 
of the other experimental varieties failed to survive. 

This work was continued, but in the meantime careful studies were 
being made in the several wheat districts with a view of determining 
the particular needs of each. In some districts greater hardiness of 
winter sorts is required; in others, varieties with a particularly tena*- 
cious chaff; in others, stiff er straw; in others, drought resistance, and 
so on. Varieties bred for North Dakota and Minnesota are of no value 
for California, and the best varieties for Texas would be useless in 
Montana. But aside from these considerations a knowledge of the 
different botanical groups of wheats is necessar}', in order to have at 
command all the sources from which ma}' be drawn the qualities 
reciuired for different districts. 

After five vears investigations it can bv no means be assumed that a 
full knowledge of the conditions of wheat culture and the demands of 
the country has been attained by this Division. Nevertheless, it is now 
possible to establish a reasonably complete basis upon which intelli- 
gent and systematic work may be accomplished — work that either 
could not be accomplished ut all from a narrower standpoint, or would 
require much more additional time than has been given to the acquire- 
ment of this foundation, and could not even then be as thoroughly 
done. 



PERSONAL EXPLORATIONS. 

At various times during the years 1894 to 1897 all the wheat States 
except New York, Pennsylvania, and the Pacific Coast States were 
pretty thoroughly explored by the writer, the conditions of soil and 
climate being noted and a careful study made of the nature and distri- 
bution of the wheat varieties. Finally, during the past season (1899), 
it became possible to make a similar investigation of such conditions 
in the Pacific coast and North Mountain States, special attention being 
given in this case to the region usually known as the Palouse Country, 
and also to wheat culture under irrigation. Naturally very valuable 
information was obtained through these personal observations, which 
will be of great use in future work in wheat improvement. 

During the summer and autumn of 1898, under the direction of the 
Section of Seed and Plant Introduction of this Department, an 
exploration was made of the greater part of European Russia, including 
the Caucasus, and of a small portion of the Kirghiz Steppes, as well 
as of Hungary and Roumania, in search of additional cereals for this 
country. A general report of this work has been published.^ In 
Huno-arv and Roumania no varieties better than our own were found 
that had not already been obtained from those countries. In Russia 
some very valuable sorts were secured, which together with four or 
five others yet to be received," give this country now practically 
ever3'thing of importance in the line of wheats from that, the second 
greatest wheat country of the world. All these explorations have 
been of great value in furnishing a long-desired opportunity for a 
comparative study of wheat varieties and the conditions of wheat 
environment in different countries. 

CHARACTERISTICS AND NEEDS OF THE SEVERAL WHEAT DIS- 
TRICTS OF THE UNITED STATES. 

From the standpoint of investigations so far made concerning the 
conditions of wheat environment and the adaptations of varieties in 
the United States, the country may be considered as divided into eight 
wheat districts, each possessing characteristics quite different from 
those of the others. In fact, in some cases they are as different from 
each other as though they lay in different continents. They are as 
follows: (1) The Soft Wheat district, including mainly the New Eng- 
land and Middle States; (2) the Semihard Winter Wheat district, 
including the North Central States; (3) the Southern Wheat district, 
including the northern part of the Southern States; (4) the Hard 
Spring Wheat district, including the Northern States of the Plains; 

^ Russian Cereals adapted for Cultivation in the United States, Bui. No. 23, Division 
of Botany, U. S. Department of Agriculture, 1900, by M. A. Carleton. 
■■'Since this was written these- varieties have all been obtained. 



10 

(5) the Hard AYinter Wheat district, including- the Middle States of 
the Plains; (6) the Durum Wheat district, including a part of the 
Southern States of the Plains; (7) the Irrigated Wheat district, includ- 
ing* in general the scattered portions of wheat area in the Rocky 
Mountain and Basin States; and (8) the White Wheat district, includ- 
ing the larger part of the Pacific Coast States. Just as these districts 
differ from each other in their characteristics, so do the particular 
needs of the wheat grower in each dijfJer widely from those of other 
districts. (See colored map, frontispiece of this bulletin.^) 

GENERAL NEEDS OF ALL, THE DISTRICTS. 

Before describing these districts separately, it will be well to note 
briefl}^ two general needs common to all of them. These are (1) greater 
yielding power and (2) earlier maturity. In the writer's experience 
these are found to be ever present needs, not onl}^ in all our own 
States but in all wheat countries. 

YIELDING POWER. 

This quality is of course always desirable, simply from the stand- 
point of obtaining the greatest possible profit from the same area. 
Nevertheless, on account of peculiar local conditions the demand for a 
large yield is given much more emphasis in some localities than in 
others. Besides, the need of a large yield does not always arise from 
the same cause, and in many cases it is not real, but only appears so 
because of defects in other regards. To illustrate, the Palouse country 
of Washington and Idaho may ])e taken as an example in contrast with 
that of the Southern States. In the Palouse country the regular aver- 
age yield is already probably near 25 bushels per acre, while 35 or 40 
bushels per acre is a common crop in certain seasons, and 60 bushels 
not particularly rare. Yet from no part of the country has the writer 
had more requests for information concerning larger-\^ielding varieties. 
As a matter of fact prices of wheat are proportional^ so low on 
account of the great distance from good mai'kets, and the method of 
summer fallowing, which allows a crop only ever}^ second j^ear, is so 

' It has been a most difficult matter to prej^are this map, and it is not claimed that 
it is accurate. Indeed it would he impossible at present to prepare an accurate map 
of this nature. But it represents ajjproximately the different wheat districts charac- 
terized mainly by the cultivation of certain natural groups of wheats. Of course the 
different groups will lap over more or less from one district to another. In all that 
part of the United States approximately east of the one hundred and fourth meridian 
the uncolored portions represent territory either from which we have no statistics, 
such as the Indian Territory, or in which the wheat itroduction averages less than 1 
bushel to the square mile. West of this line the Mhite portion represents territory in 
which there is practically no wheat grown at all. The reports of the census of 1890 
and those of the Irrigation Division of the Geological Survey have been of much help 
in the preparation of the map. 



11 

much practiced that to overcome losses in these directions exceeding'ly 
laro-e yields are considered necessarj' in order that much prplit may 
be gained in the end. On the other hand, in the Southern States the 
problem of increasing the yield is entirel}^ independent of deficiencies 
in other regards, for the home demand alone is sufficient to make 
prices good as a rule; but the average yield is extremely low, being 
under 10 bushels per acre. It would add one-half to the profit in 
these States if the yield could be increased even to the average of the 
entire country (slightly over 13 bushels per acre). In the South 
manuring the land must also be practiced in order to obtain the best 
results, which is an item not at present considered in the West. 

In the States of the Plains the actual average yield is also rather low 
(a little over 12 bushels), so that here, too, the reason for a demand 
for an increased yield is evident and is usually independent of other 

deficiencies. 

The average yield for the United States is far lower than it ought to 
be. The yield for the semiarid districts, which is much less, can and 
should be as high as that for the entire country at present. 

EARLY MATURITY. 

There is no part of the United States where early maturing wheats 
ar(^ not desirable for one reason or another. The reasons are various 
in difi'erent localities. As before stated, early ripening varieties are, 
in most seasons, more likely tp escape damage by rust. In a large por- 
tion of the country this is a very important matter for consideration, 
but especially so in the Southern States and the States east of the Mis- 
sissippi River, where the whole wheat crop is occasionally entirely 
destroyed by this parasite. But the need of early maturity is most 
ui-gent in the Palouse country, as the shriveling efi'ects of the annual 
dijought in that region which sets in just before harvest may be avoided 
l)y the use of early varieties. In the North Central States and the 
Great Plains region early maturing and winter varieties are less liable 
to the ravages of chinch bugs than are late maturing and spring varie- 
ties. In all the Northern States early maturity also allows the variety 
a l)etter chance to escape early autumn frosts. 

There are instances in which late maturity is apparently an advan- 
tage, but such cases are rare. 

Finally it should be noted that there is quite a distinction between 
early wheats and early-sown wheats. A late-maturing wheat will ripen 
earlier than usual if sown earlier, or will ripen still later than usual if 
sown later. In the case of winter wheats early seeding allows the wheat 
plant to accunmlate more reserve force in th(^ roots during the autunni, 
tluis enabling it to begin growth with greater vigor in the spi'ing and 
get the start of the later-sown crops. In the case of spring sorts earlier 
seeding, of course, simply I'naljles the crop to get an earlier start and 



12 

thereby to ripen earlier. By early sowing and the constant selection 
of the earliest ripening heads for seed a naturally late wheat may bj 
gradually transformed into an early variety. 

SOFT WHEAT DISTRICT. 

In this district are included approximately New York, Pennsylvaj 
nia, New Jersey, Maryland, Delaware, and portions of Virginia (Plate 
I), West Virginia, and eastern Kentucky; also such portions of New 
England as produce wheat to any considerable extent. The region is 
characterized on the whole by the production of rather soft wheats, 
containing a large amount proportionally of starch, though occasion- 
ally they incline to semihard. The color of the grain is usually yel- 
lowish white or amber, but sometimes quite reddish. The soil, 
especially if not heavily fertilized, does not possess the necessary 
amount of alkali, phosphate, and humitied organic matter required 
for the production of hard, glutinous wheats. Moreover the climate 
is against their production, being too moist and cool in summer. 
Nevertheless in New York and Pennsylvania, by means of the plenti- 
ful application of fertilizers and the unusual attention paid to seed 
selection practiced in this region, a large amount of good wheat is 
annually grown in proportion to the entire area. Twenty-five or 
thirt}^ years ago, when the area given to wheat culture in this country 
was much more limited than at present, and when the hard red wheats 
were not so popular. New York had a deservedly great reputation 
both for her wheat production and flour'industry. And even at pres- 
ent, if there is a diminution of this reputation, it is not because of any 
actual decrease in wheat and flour production, but because of the over- 
shadowing increase in districts more favorably conditioned or situated, 
though we should add to this the fact that there has been a corre- 
sponding change in the kind of wheat used for bread making. The fact 
that so high a standard is maintained in the wheats of this region in 
the face of adverse natural conditions, is strong proof of the importance 
of intelligent wheat culture, particularly in respect to seed selection 
and the proper treatment of the soil. In some localities of this dis- 
trict the standard is considerably above what one would expect, while 
in some other districts it is far below what it should be. 

In the most northern portions of this district spring sowing is almost 
entirely practiced, and there is a need for hardy winter sorts which 
will be able to extend the winter-wheat area farther northward. In 
some localities rust is occasionally very injurious, the black stem rust 
sometimes completely destroying the crop. Early maturing and rust 
resistant sorts are therefore desirable for escaping or overcoming the 
attacks of this parasite. 



Bui. 24, Div. Veg, Phys. & Path., U. S. D-pt. of Agriculture. 



PLATiI I. 




13 

SUMMARY OF CONDITIONS AND NEEDS OF THE DISTRICT. 

(1) Chief varieties now grown: 

Fultz, Fulcaster, 

Early Genesee Giant, Longberry, 

Jones's Winter Fife, Mediterranean, 

Eed Wonder, Early Red Clawson, 

Gold Coin, ' Blue Stem. 

(2) Average yield per acre, about 14| bushels.' 

(3) Needs of the grower: 

(a) Harder-grained, more glutinous varieties. 

(b) Hardier winter varieties for the most northern portions. 

(c) Early maturity. 

(d) Rust resistance. 

SEMIHARD WINTER WHEAT DISTRICT. 

Ill this district we may include Ohio, Indiana, Illinois, Michigan, 
and a small part of Wisconsin. It produces a wheat of medium 
qualit}^, and on the whole is one of the most important cereal regions 
of the United States. The wheats grown are generally semihard, 
rather reddish in color, and either bald or bearded. Throughout this 
district, as well as over a large portion of the country, there has been 
a decided tendency during the last twenty years or more toward the 
use of harder red wheats and also of a larger proportion of winter 
compared with spring varieties. The increasing use of the harder 
wheats has been coincident with the advent of the roller-milling proc- 
ess, but not necessarily a forced result of the latter, as some have 
inferred. The two have worked together. The proportion of such 
wheats now grown in this region is nuich larger than ten years ago. 
Especially is this true in Michigan, where special impetus has been 
given to such improvements through the efforts of Prof. R. C. Kedzie, 
assisted by the millers of the State. Similarly the area in which it 
is considered possible to grow winter wheats has been extended much 
farther noi'thward, now including practically all of Michigan, nearly 
all of Illinois, and even a small portion of AVisconsin. Thus this 
group of States may now be properly called the semihard winter 
wheat district. These changes have been accomplished by the grad- 
ual introduction of hardier winter sorts, which are at the same time 
usually harder and red grained. Nevertheless there has been little 
more than a beginning in these improvements, and there is still a 
demand for hard red wheats, and in the northern portion of the 
roo-jon for hni'dicr winter varieties. 

The black stem rust is sometimes very d(>structive in these States, 
particularly in the lower, moist, and timbered portions of Ohio, 
Indiana, and Michigan. Hence there is great demand also for rust 
resistant sorts. 



'Calculated ai^ accurately as possible from data collected by the Division of Statia- 
tics of this L)ei)artmeut covering the perioil IS'.IO-lHUy. 



14 

SUM>rARY OF CONDITIONS AND NEEDS OF THE DISIRICT. 

(1) Chief varieties now grown: 

Fultz, Poole, 

Eudy, Valley, 

Early Red Clawson, Nigger, 

Dawson's Golden Chaff. 

(2) Present average ji.eld per acre, about 14 bushels. 

(3) Present needs of tlie di«trict: 

(a) Hardness of grain. 

(b) Eust resistance. 

(c) Hardy winter varieties. 

SOUTHERN ^VHEAT DISTRICT. 

In area this district includes the larger portion of Kentucky, Vir- 
ginia, West Virginia, and North Carolina, all of Tennessee, and portions 
of South Carolina, Georgia. Alabama. Arkansas, and Missouri. The 
annual production of wheat is comparativeh' small, and is furnished 
principally by Kentucky, Missouri, Tennessee, and Virginia. In the 
greater portion of the region the combination of great rainfall with 
mild temperature is not conducive to the greatest success in wheat 
growing. The soil is also generally not of the best for such purposes. 
Rust is always ver}^ bad, because of the constantly damp, warm climate. 
In spite of these difficulties there is no doubt that with sufficient effort 
the wheat industry might be very materiall^^ improv-ed. Just recently 
there has been much interest awakened in the possibilities of success- 
ful wheat culture, particularly in Georgia and South Carolina. This 
increasing interest in the matter finalh' resulted in the calling together 
of a convention at Macon, Ga.. in July, 1899, when it was unanimously 
decided that Georgia can veiy easily and should supply her own 
demands for wheat for bread making. Man}^ members of the conven- 
tion gave very favorable testimon}" regarding their own experiences 
in wheat growing during the past year. Probably one of the greatest 
obstacles in the way of profitable wheat raising in portions of the South 
is the lack of good flouring mills, much of the grinding being at pres- 
ent performed by the most primitive of gristmills. With a continued 
increase in wheat acreage there will perhaps be a corresponding 
increase in the number of iii'st-class mills constructed. 

On account of the severe rust attacks which occur in this district it 
is highl}' desirable to grow early ripening and rust resistant sorts. 
But there are really not many early matui'ing wheats grown in this 
country, and of the early foreign varieties already tested none have 
yet proved to be sufficiently hardy. Canning Downs, an early Austra- 
lian sort, winterkilled even in so mild a region as Mississippi.^ How- 

^See Tracy, S. M. T^Tieat. Sixth Annual Eeport Mississippi Agricultural Expert 
iment Station, 1893, pp. 23-25; also Eighth Annual Eepoi't, 1895, pp. 44-46. 



15 

ever, there has not been a sufficient number of trials of such varieties, 
and the different experiments have not been often enough repeated to 
give reliable results. As to the matter of rust resistance, experiments 
made in Louisiana^ showed that hard red wheats, including a number 
of Russian origin, resisted rust the best. In Mississippi two Austra- 
lian varieties, Beloturka and Defiance, were quite rust resistant, while 
varieties obtained from England rusted very badly. ^ 

Occasionally wheat is much injured in the noi'thern portion of this 
region l)y late spring frosts. It is on such occasions that late-maturing 
wheats and late-sown crops may have the advantage, since those ripen- 
ing early are likely to be caught by the frost just at blooming time 
and be prevented from "filling out," while the later ripening crops, 
blooming after the frost, escape such injury. It seems possible, how- 
ever, to p-row varieties that will resist the action of these frosts, and 
therefore varieties hard}' in this respect are desirable. 

The wheats at present grown in the Southern Wheat district are 
either soft or semihard, and usually amber or reddish in color. They 
are either bearded, as in the case of the Fulcaster, or beardless, of 
which the Fultz and May wheats are examples. In Arkansas and the 
Carolinas, Nicaragua wheat, a durum variety, is grown somewhat, but 
to no great extent as yet. Wheat from the Southern States is always 
more likely to be infested with weevil than that from other districts, 
and occasionally much annoyance as well as injury to the grain results 
from this cause. Nicaragua and the hard red wheats are more resist- 
ant to weevil than are the soft wheats. 

SUMMARY OF CONDITIONS AND NEEDS OP DISTRICT. 

(1) Principal varieties at present grown: 

Fultz, Rice, 

Fulcaster, Everett's High Grade, 

Red May, Bough ton, 

Currell's Prolific, Purple Straw. 

(2) Present average yield per acre, about 9| bushels. 

(3) Needs of the grower: 

(«) Rust resistance. 
(6) Early maturity. 

(c) Resistance to late spring frosts. 

(d) Stiffness of straw. 

HARD SPRING WHEAT DISTRICT. 

The hard spring wheat area comprises the States of Minnesota, 
North Dakota, South Dakota, the larger part of Wisconsin, portions 
of Iowa and Nebraska, and small portions of Montana and Colorado. 

'SeeStub1)s, W. C. Experiments in wheat. Louisiana Agricultural Experiment 
Station Bulletin No. 19, 1892, 2(1 scries, pp. 555-.562. 

■•'See Tracy, S. M., in Mississippi Agricultural Exiieriment Station reports above 
cited. 



16 

In this district, because of the rich, black soil and dr}-, hot suminoi's, 
there is grown the highest grade of spring wheat in the world, except- 
ing the spring varieties of the middle Volga region in Russia, which 
are very siniihir. 

Two general types of wheat prevail throughout this district — the 
Velvet Blue Stem' and the Fife. A large proportion of the farmers 
in this region know no wheat which does not belong to one of these 
types. The chaff of the Velvet Blue Stem is covered rather closely 
with small hairs, and the plants are bluish gray near harvest time. 
In both types the heads are beardless and the grains are medium or 
small, hard, and red. There are several strains or varieties of each 
type. The gluten content of these wheats is comparatively very large, 
and especially of that quality which gives great lightness in bread 
making. 

The average annual wheat production of this district is larger than 
that of any other siuiilar area in the WT)rld, and is about 30 per cent of 
the entire production of the United States, The average yield per 
acre, however, is not very large — certainly far below what it might be. 
Almost everywhere the self-I)inder is used in harvesting the grain, and 
in some localities the farms given entirelv to wheat culture cover many 
thousand acres. (See Plate II.) On these bonanza farms 50 to 100 
self -binding liarvesters are sometimes at work at the same time. The 
large size of the farms is one of the worst features connected with 
wheat growing in the Northwest. From this cause not enough atten- 
tion is given to details of the work. Operations delegated to the best 
of foremen and other emplo3^ees are never so carefull}' performed as 
when done under the direct scrutiny of the man who owns the farm, 
and wliose interests are therefore at stake. Little things that are of 
importance when summed up are overlooked. The tillage is not thor- 
oughl}^ accomplished, weeds are not kept down, there is more or less 
waste of land, and the grain is allowed to degenerate in quality. 

The needs of the grower in this district are not so great as in some 
others, though there is much to l)e desired. In the northern portion 
earliness of maturity is needed to enable the wheat to escape the early 
autumn frosts which sometimes catch the crop before harvest, while 
in the southern portion chinch-bug depredations and rust attacks might 
often be avoided through possession of the same quality. A combina- 
tion of earliness and rust resistance in the same variety would be espe- 
cially desirable. The average yield could be made ver}^ much larger, as 
already stated, but this is a matter depending fully as much on methods 
of culture as on the improvement of varieties. Proper seed selection, 

' There are apparently four distinct varieties of so-called Blue Stem in the United 
States. The name Velvet Blue Stem is adopted here to designate the spruig variety 
grown in this district. The one grown in the Palouse country will 1)e called Palouse 
Blue Stem. 



Bui ?4 Div. Veg. Phys. & Patn.. U. S. Dept, of Agriculture. 



Plate II. 




Fig. 1.— Wheat Fields of the Red River Valley, near Grand Forks, in. Dak. 

(Original.) 





■ !'■ ' » ». 



Fig. 2.— Self-binders at work near Grand Forks, N. Dak. (Original. 



17 

however, .should be rigidly practiced. The (\stiil)li.shuu'nt of hardy 
winter varieties in place of the spring -varieties now grown would no 
doubt be an improvement of the utmost value in Iowa, Nebraska, and 
portions of Wisconsin, and perhaps a small part of Minnesota. This 
border is now the battle ground between winter and spring varieties, 
and it should be the constant aim to carry the line farther to the north, 
thus increasing more and more the winter-wheat area. Such purpose 
can be accomplished either (1) by the introduction of winter varieties, 
of similar quality to the spring sorts now grown, from the Crimea, 
north Caucasus, and southern Volga region of Russia, or (2) by the 
actual origination of hardier winter varieties of good quality through 
hybridization and selection. As an example of the effectiveness of the 
former method, we have only to point out the work already accom- 
plished by Turkey wheat — a Crimean variety — in extending the Avinter- 
wheat area in Nebraska and Iowa. 

SUMMARY OF CONDITIONS AXli NEEDS OF THE DISTRICT. 

(1) Principal varieties at present grown: 

Saskatchewan Fife, Hayne's Blue Stem, 

Scotch Fife, Bolton's Blue Stem, 

Powers Fife, Wellman's Fife. 

(2) Average yield per acre, about 13 busliels. 

(3) Needs of the grower: 

{a) Early maturity. 
{})) Rust resistance. 

(c) Hardy winter varieties. 

(d) Drought resistance. 

HARD WINTER W^HEAT DISTRICT. 

In this district is comprised approximately the middle States of 
the plains, including Kansas, a large part of Missouri, portions of 
Iowa and Nebraska, and the larger part of Oklahoma. As the name 
implies, it is characterized b}- the production of hard winter wheats, 
such wheats as are rareh' found, but which are of the veiy best ({ualit}'. 
The onl}^ other wheat region in all the world tliat is exactly com[)ar- 
able to this one, so far as known, is that including northern Crimea 
and the country directly between the Sea of Azov and the Caspian 
Sea. The latter region, however, at present produces better wheats 
than are produced in this district, and therefore should ])e drawn upon 
for all improvements that are attempted through introduced sorts. 

The wheats of this district luue slender, stiff stems, narrow com- 
pact heads, usually bearded, and medium or small, hard, red grains. 
In this region there is tiie most interesting exampU* of the changes 
that may take place for the better in the development of the wheat 
industry. Twenty-five years ago the softer wheats (often white- 
grained) were chiefly grown oxer a large portion of this district, and 
.1871)— No. 2i '2 



18 

the cases of winter wheat sowing- as against spring wheat sowing were 
much fewer than at present. Now the hard red-grained varieties are 
principal!}' used, and only in Iowa and Nebraska are spring varieties 
grown to any extent. The introduction of these hard-grained winter 
sorts has added remarkably to the certainty and value of the wheat 
crop, and has greatly decreased the ravages from rust and chinch 
bugs. 

Such improvements are after all l:)ut fairly begun, and there is yet 
great demand for hai'd-grained sorts and varieties that will resist the 
winters of Iowa and Nebraska. As the wheat area extends farther 
westward — to the one hundredth meridian and beyond — there is also 
a special need for drought-resistant sorts. In fact, in this and the dis- 
trict just described there is the most exacting demand of the entire 
country for hardy varieties. The extreme severit}^ of the drought 
and winter cold combined forms a greater obstacle to winter wheat cul- 
ture than exists in any other district. The average j^ield per acre is 
alwa3's low, but the problem in a considerable portion of the region 
is not so much to increase the yielding power per acre as to make 
sure of a crop every year, since there are so man}^ complete failures 
from drought. A constant average of even 12 to 15 bushels per acre 
from year to year would be considered good.^ 

Early maturity is of importance in this district in order to allow 
an escape from the worst eflects of the drought in the western portion 
and from the rust in the eastern portion. Rust resistance is also 
important, but not so much so as in States east of the Mississippi 
River. 

SUMMARY OF CONDITIONS AND NEEDS OF THE DISTRICT. 

(1) Chief varieties at present grown: 

Turkey, -^J^ay, 

Fulcaster, Zimmerman, 

Fultz. 

(2) Average yield per acre, alj(jut 12| bushels. 

(3) Needs of the grower: 

(a) Hardy winter varieties. 

(b) Drought resistance. 

(c) Early maturity. 

DURUM WHEAT DISTRICT. 

The area contained in this district is comparativelj^ small and 
includes a large part of north-central Texas, the southwestern portion 
of Oklahoma, and a small portion of the southwest corner of Kansas. 
It also properly includes a portion of Colorado, but can not be so 
indicated on the map, as the particular portion is not yet definitely 
outlined. Some of this region (southwestern Oklahoma) has only 

^ The problem of successful wheat growing in arid regions is receiving .earnest 
consideration and will be discussed in a later publication. 



1^) 

recently been opened to .settlement, but wheat culture ha« developed 
rapidly in the new lands. The soil is generally black and rich in 
humus, just as in the district last described, and produces wheats with 
a large gluten content, which quality is further increased in the west- 
ern portion by the dry. hot summer weather. The general demand 
is for hard-grained, drought-resistant varieties, and such sorts are 
already grown to a considerable extent. In recent years there has 
been an increasing tendency toward the cultivation of the durum or 
macaroni wheats, the chief variety grown so far being Nicaragua 
which has become quite popular. This variety is very hardy, yields 
well, and the grain is extremely hard and glutinous. It is quite simi- 
lar to Ku))anka. Arnautka, and other macaroni wheats grown in 
southern Russia, and for which there is so much demand in France 
and Italy. Notwithstanding the usual notion concerning such wheats, 
Nicaragua has been very successfulh" ground into flour by a well- 
known milling company at lort Worth, Tex. By mixing slightly 
with other wheats an excellent bread flour is made. However, the 
chief profit to ])e gained frc^ni the cultivation of this variety in futui'e 
will no douljt arise from its use in manufacturing macaroni, just so 
soon as the possibility of furnishing a sufficient supply becomes cer- 
tain. Though its distribution is not yet very wide, Nicaragua is, 
nevertheless, grown over a lar^-e portion of Texas and also sparingly 
in Oklahoma and Colorado. For this reason, and because of the evi- 
dent adaptation of such wheats to this region, it seems proper to call 
it the durum Avheat district. 

These durum wheats grow rapidly, are tall, and have wide leaves with 
a harsh surface, and large heavy-bearded heads, compactly formed. 
The grains are very larg(> and long, and yellowish-white in color, 
becoming darker the blacker the soil in which the crop is grown. It 
being once proved that durum wheats succeed well, there is bound to 
be a still greater demand for them, so that the further introduction of 
such varieties l)ecomes at once one of the needs of the district. Aside 
from macaroni varieties, the red-grained winter wheats, similar to 
those described for the Hard Winter Wheat district, are best adapted 
for the larger part of this region. The best example is the Mediter- 
ranean, which is very conmionly grown. 

In central and southwestern Texas rust is very destructive, so much 
so that wheat cultuie has been completely abandoned in many places 
on account of it. There is, therefore, a great demand for rust resist- 
ant varieties. The durum wheats have the advantage of being highly 
resistant to orange leaf rust, but succumb to black stem rust. In the 
western poi-tion of the district the oft-recurring droughts are very 
detrimental, and therefore in that ])<)rti()n drought resistance and (>arly 
maturity are important (lualities. 



20 

SUMMARY OF CONDITIONS AND NEEDS OF THE DISTRICT. 

(1) Chief varieties at present grown: 

Mediterranean, Fulcaster, 

Nicaragua, Turkey. 

(2) Average yield per acre, II5 bushels. 

(3) Needs of the grower: 

(a) Macaroni varieties. 

(6) Drought resistance. 

(c) Rust resistance. 

(d) Early maturity. 

IRRIGATED WHEAT DISTRICT. 

In this region is included all those scattered portions of the Rocky 
Mountain and Basin States in which wheat is grown at all. The States 
thus included are Wyoming, a part of Montana, southern Idaho, Utah, 
Nevada, Arizona, New Mexico, and the greater part of Colorado. In 
this district we find conditions remarkably difi'erent from those exist- 
ing anywhere east of the Rocky Mountains. Three striking charac- 
teristics not present to so great a degree in any other district are (1) 
the extreme aridity, necessitating the application of water by irriga- 
tion, (2) the very low humus content of the soil, and (3) the superabun- 
dance of alkali usually present. These conditions are closely inter- 
related and mutually dependent upon one another. The absence of 
humus is a natural result of the absence of rainfall, upon which 
depends the existence of plant life. Rainfall also tends to equalize the 
distribution of the alkaline matters of the soil, which in this district, 
however, are concentrated, in places, in high percentages. The prac- 
tice of irrigation is often allowed to make conditions worse by grad- 
ually carrying and depositing in certain localities or on certain farms 
an excess of alkali largely above that which was already present. 
These features of extreme aridity, lack of humus, and excess of alkali 
are so particularly characteristic that they go far beyond any matters 
of temperature dependent upon latitude or elevation in their effects 
upon the nature of wheat varieties grown in this district. That is, 
wheats so far north as southern Idaho are very like those of southern 
New Mexico or Arizona, and in all parts of the district show uni- 
formly a great lack of gluten content, which is dependent mainly upon 
the presence of soil humus. 

Wheat does best in soil that is alkaline rather than acid in reaction, 
but an excess of alkali becomes very injurious. Different cereals are 
able to withstand different amounts proportionally of alkali in the soil. 
Barley and rye seem to tolerate a larger proportion than wheat, and 
the latter will usually tolerate a larger amount than oats. Of all the 
cereals barley will withstand the largest amount. 

The wheats of this district are almost always white-grained, soft, and 



21 

extremely starehy, and lack greatly in gluten content. The straw is 
so white and clean and glistening- that it is dazzling to the eyes in the 
hot sunshine. Rust on wheat is seldom injurious, and in some locali- 
ties is entirely unknown. Smut, howeyer, is often present to a con- 
siderable extent. The stiffness of the straw and the absence of rain 
preyent the grain from eyer lodging, so that haryesting may be 
delayed for weeks with little or no injury to the grain. 

Manifestly the greatest need of this district is an increase in the 
gluten content of the grain. While the introduction of hard-grained 
nitrot'-enous sorts from other sections is at first an improyement, the 
gluten content can not thus be materially and permanently increased. 
No wheat yariety, whatever its nature, can abstract from the soil ele- 
ments that are not present there. Wheats l)rought f rom the black 
prairie soils of other sections to this district show the most striking 
illustration of the radical changes that may be caused in a yariety by a 
simple transference to a new locality, and, eyen when grown under the 
best of care, quite etfectually disprove a notion prevalent eyen among 
scientists that yarieties will not deteriorate. The hardest red Fifes 
from North Dakota, Turkey wheat from Kansas, or Diamond Grit from 
New York become rapidly more starchy and of a lighter color on being 
grown in Utah or New Mexico. The first requisite, therefore, for 
wheat improvement in irrigated sections is the complete amelioration 
of the soil by (1) dispersing the excessive accunuilations of alkali and 
(2) increasing the humus content through the application of nitrogenous 
fertilizers and the growth of leguminous crops in alternation with wdieat. 
At the same time it will aid greatly to gradually introduce the harder 
red-p-rained wheats. 

In many portions of this district, at high elevations in the moun- 
tains, wheat is often seriously damaged by early autunm frosts. It is 
therefore important to obtain for these localities the earliest maturing 
varieties possible, or varieties that may perhaps resist the action of 
the frost. For example, in the San Luis Valley of Colorado wheat is 
trrown at an elevation of over 7,500 feet, where frost is likely to occur 
in any month of the year, but is especially liable to injure the crop in 
August. 

SUMMARY OF CONDITIONS AND NEEDS OF THE DISTRICT. 

( 1 ) Chief varieties now grown : 

Sonora, Little Club, 

Taos, Defiance, 

Felspar, Amethyst. 

(2) Averajje yield per acre, about 21 bushels. 

(3) Needs of the grower: 

(a) Increase of the gluten content, 
(i) Pearly maturity. 



22 



whitp: wheat district. 



This district covers, in a general way, the Pacific Coast region, in- 
cluding California, Oregon, Washington, and northern Idaho. All 
varieties that have become at all acclimated are characteristically white- 
grained, soft, and starchy. Usually the factor which is probably most 
influential in producing a grain of such nature is the lack of humus in 
the soil, as is true in the irrigated district. The generally cool sum- 
mers, however, no doubt give aid to the same end. Hard red-grained 
varieties, when Ijrought to this district, deteriorate in a few years time. 
Nevertheless such introductions have in a number of instances proved 
beneficial. 

A majorit}^ of the more common varieties strictly characteristic of 
the district are of the group usually called club wheats and belong 
to the species Trlticmit cmn].)actum. Sonora, Defiance, and Australian 
of California, Red Chaff of Oregon (distinct from the Palouse Red Chaff' 
of the Palouse country), and Palouse Blue Stem of Washington are 
not, howev^er, club wheats. As the botanical name of the clul) group 
implies, these wheats have their spikelets (meshes) so compactly 
arranged in the heads that they stand out nearly at right angles with 
the rachis (or stem of the head). The head thus becomes squarely 
formed (hence the name square head applied to many of the varieties), 
and, ])eing usually a little larger at the apex than at the base, Appears 
club shaped. Thus, although the heads are usually rather short, each 
contains comparatively a large number of grains, which partially 
accounts, probably, for the large yields per acre in this district. Heads 
of Chili Club are occasionally found that contain over 160 grains each. 

A very valuable characteristic of the club wheats is their ability to 
hold the grain in the chaff so that there is little danger of shattering, 
even durinof the driest season, if there should be much delav in the 
harvest. In some localities the grain, though ripening in July, is 
sometimes left standing till September before harvesting, a habit which, 
however, has no good excuse for its practice. 

For the purpose of clearer discussion, the district may be considered 
as subdivided into three sections — California, Oregon, and the Palouse 
country of Washington and northern Idaho. 

In southern California the varieties Sonora and Defiance are much 
grown, the latter particularly for its rust resistance, which is an im- 
portant need in this part of the State. Sonora wheat has a reddish 
velvet chaff, is beardless, and is white-grained as seen in this district. 
The grain is a little harder than that of the club wheats and is used 
for export, while the grain of the latter is used for home consumption. 

From the latitude of Fresno to the Oregon State line Austndian and 
the various strains of club wheats are principally cultivated. The best 
known varieties that are given special names at all are Golden Gate 
Club, Salt Lake Club, and Chili Clul). The variety Propo is also 



Bui. 24, Div. Veg. Phys &. Path., U. S. Dept. of Agriculture 



Plate III. 




Fig. 1.— Field of Wheat on "Tule" Lands near Stockton, Cal. (Original.) 




Fig. 2.— bTEAM Combinld Harvester-thresher harvesting on Tule Lands near 

Stockton, Cal. i Original. - 



Bul^ 2A Div. Veg. Phys. & Path.. U. S Dept. of Agriculture. 



Plate IV. 




Fig. 8.— Bags of Wheat just harvested on the Bidwell Estate, Chico, Cal. 

(■Original. 







.v •,■ 






•v;:v'?' 







Fig. 2.— Wheat Field near Tehama, Cal. < Original. 



23 

grown to some extent. Other sorts from the East, such as Rudy, are 
occasionalh^ introduced, l)ut these do not seem to yield so well, and 
besides shatter so badly that they soon have to be given up. Nonshat- 
tering varieties are in great demand. In all portions of the State the 
increase of the gluten content is probably the greatest need. All varie- 
ties grown in the State arc winter wheats. 

One of the most interesting sections of California devoted to wheat 
culture is that of the "Tule" lands, near Stockton. (See Plate III, 
fig. 1.) The great grain fields there show strikingly the possibilities 
in a reclamation of immense marshes. They were once vast flats cov- 
ered with water, mud, and a growth of bulrushes {Sc/'rj)u.s lacmtris)^ 
called Tule in Spanish. By means of pumping, dredging, and throwing 
up levees these lands have been reclaimed, and now after many years 
they are among the most fertile of the State. Wheat yields from 50 
to 80 bushels per acre here, and barley sometimes as much as a hun- 
dred ])ushels or more per acre. This remarkable fertility is a result, 
in part at least, of the deep deposits of organic matter. There is still 
apparently a lack of certain mineral ingredients, such as lime and pot- 
ash, which are needed to make the quality of the grain as good as the 
quantity. 

As in the case of the Hard Spring Wheat district the chief difiiculty 
in the way of successful wheat culture in California, so far as agricul- 
tural practice is concerned, is the enormous size of man}^ of the farms 
or ranches. They are even hirger than in the Dakotas and Minnesota, 
containing often from 20,000 to 30,000 acres. On this account it is 
impossible to give the attention to details in farming that are necessary 
for the best results. The lack of attention to nitrogenous manuring, 
and especially to the alternation of wheat with leguminous crops, is 
particularly noticeable. 

The combined harvester-thresher (Plate III, fig. 2) is used in har- 
vesting pretty generally throughout the State. This machine is either 
drawn with an engine or with 28 to 40 horses. By its use the grain is 
thrashed directly from the field, and left piled in bags. (See Plate IV, 
fig. 1.) Inmiense ricks of these bags of grain remain in the field 
sometimes for weeks umnolested and undamaged b}' the weather. All 
grain throughout the State is handled in this form and calculations are 
made in bags and not in bushels. There is therefore no use for the 
grain elevator, in the ordinary sense of the term. Each ])ag contains 
2i Itushels or about 150 pounds. 

West of the ('ascades, in Oregon, conditions are somewhat similar 
to those in California. In a large portion of the State a consid(M-al)le 
amount of spring wheat is grown. In addition to the ordinary club 
wheats some other varieties, such as Oregon Red Chafi" and Foise, are also 
well represented. The midsununci-c limatcMs much cooler than in (Cali- 
fornia, and therefore harvesting is performed nuich later. On account 



2-1 

of the greater dampness of the atmosphere and the smaller size of the 
farms combined harvester-threshers are not used, but self-binders 
instead. There is great need of early maturing varieties, as the cool 
autumn weather begins so early. The nitrogen content of the grain 
is exceedingly small. 

In eastern Oregon climatic and other conditions are quite diflerent 
from those west of the Cascades, and a description of that section is 
more properly included in the discussion of the Palouse country. 

In western Washington the general conditions and the cjuality of the 
wheat are very similar to those of western Oregon, but in southeastern 
Washington and adjacent portions of Idaho and Oregon is a large sec- 
tion known as the Palouse country, which possesses peculiarities of soil 
and climate that are distinctively characteristic and radically different 
from those of the Pacific Coast region proper. Strictly speaking, the 
Palouse country is con.'5idered to be rather limited in extent, compris- 
ing approximately Latah County, Idaho, and Whitman Count}-, and 
very small adjoining portions of Adams and Franklin counties, in Wash- 
ington. Recently, however, the term has come to be applied practically 
to nearly all of these last-named counties, as well as to Garfield, Colum- 
bia, and Walla Walla counties (Plate V), and may even include the 
northern portion of Umatilla County, Oreg. The two features which 
most distinguish this region from the Pacific Coast proper are the dry- 
ness of the climate and very finely divided condition of the soil. The 
particles are so very tine that when dry the soil is practicall}^ mere 
dust. On windy daj's this dust fills the air, forming vast clouds that are 
very disagreeable to the traveler. At the same time, with very little 
rain the soil becomes quite sticky and diflicult to manage. The capacity 
of the soil to al)Sorb and retain moisture is remarkable. It is pretty 
generall3Mjelieyed that a rainfall of 12 inches in this district is sufficient 
to make a crop of wheat, while in the States of the Plains 18 inches is 
considered to be rather low for successful wheat growing. Wheat is 
the chief crop of the region, though barley and oats are grown to some 
extent. The principal wheat varieties (except Palouse Blue Stem) are 
of the cluli-wheat group. They are usually soft grained and starchy, 
and generally white, similar to those of the coast region, but a little 
better in qualit}. The three standard varieties commonly grown are 
Palouse Blue Stem. Palouse Red Chaff', and Little Club. As regards 
the comparative distribution of these varieties, if the region be con- 
sidered as divided into three parallel north and south belts, it will be 
found that Palouse Blue Stem prevails in the western belt, extending 
as far westward as North Yakima; Palouse Red Chaff' in the middle 
belt, passing through the heart of the region, and Little Club in the 
eastern belt, reaching the foothills of the mountains. 

The most serious obstacle to successful wheat culture in the Palouse 
country is the annually recurring drought which occurs about two 
weeks before harvest time, particularly in the western and southern 



Bui 24, Div Veg. Phys. & Path , U. S. Dept. of Agriculture. 



Plate V, 




Fig- 1.— Harvesting with the Combined Harvester-thresher near Walla Walla, 
Wash, i Photographed by A. B. Leckenby. > 




^^^ -r • 



^ 'r'm'^ 



,V,. 



Fig. 



uJ;.-;uiiik\ .k .: »; w'Jtu ■ 'j;iif^^^ ■ '^ Vi>a: ■ 



'^^I^ISi 



-Wheat Fields before and after harvesting, near Walla Walla, Wash 
(Photographed by A. B. Leckenby. ' 



25 

portions. From this cause the wheat is often badly shriveled, and l>oth 
the yield and quality there1)y much att'ected. A slight compensation 
for this loss lies in the fact that shiiveled wheat in this district is more 
in demand for making macaroni than plump wheat, because of the 
greater proportional amount of gluten in the former. In order to 
escape the severe eti'ects of the drought, early maturing sorts are 
exceedingly desirable. It would probably be no exaggeration to say 
that a variety ripening ten to fifteen days earlier than the varieties now 
used, and as good in other respects, would add from one to three 
million dollars a year to the wealth of this region. In the central 
and southern portions of the region fall sowing is chiefly practiced, 
but in the northern and eastern portions, near the mountains, there 
is a larger proportion of spring varieties, and there a good, hardy 
winter sort is needed. In the drier western and southern portions, 
especially in the vicinity of Walla Walla, nonshattering varieties 
are necessary. There the combined harvester-thresher (Plate VI, 
fig.l) is used in harvesting, as in California. In the north and east, 
and in the more hilly portions, as in the vicinity of Colfax, the self- 
binder is more commonly employed. In a few places a comparatively 
new^ sort of machine has recently come into use. (Plate VI, tig. 2.) 
It makes a 10 or 12 foot cut, and is driven in front of the horses, as 
in the case of a header, but unlike the latter possesses a self-])inding 
attachment as well. 

SUMMARY OF CONDITIONS AND NEEDS OF THE DISTRICT. 

(1) Principal varieties at present grown: 

Australian, Palouse Blue Stem, 

California Club, Palouse Red Chaff, 

Sonora, ■» Little Club, 

Oregon Red Chaff, White Winter, 

Foise. 

(2) Average yield per acre, about 14f bushels. 

(3) Needs of the grower: 

(a) Early maturity. 

(6) Nonshattering varieties. 

(c) Hardy winter varieties in the colder portions. 

SOURCES FOR DESIRABLE dUALITIES. 

Having descriVjed the characteristic features of the different wheat 
districts of the country, and having noted the most pressing needs 
of the grower in each one, respectively, it will now l)e api)r()priate to 
discuss the sources from which the desii-able qualities may be ()l)tained 
for satisfying these needs. This subject may be considered from two 
different' standpoints, (1) the botanical subdivisions of th(> cultivated 
varieties of wheat (Triticum) in the broadest sense, and (2) the geo- 
graphic groups of varieties characteristic of difl'crent regions of the 



2(> 

world. Manifestly a complete treatment of the subject can not be 
presented in the present state of om' knowledge, since wheat varieties 
and their adaptations have not been thoroughlj' studied in all parts of 
the world. Nevertheless, considerable investigation has been made in 
this line, and the future promises still more. Such studies are exceed- 
ing-ly interesting, and form an absolutely necessary part of the basis 
for rational wheat improvement. 

CHARACTERISTICS OF BOTANIC GROUPS OF WHEAT. 

The cultivated varieties of Triticum., according to Kornicke and 
Werner,^ whose classification will in the main be followed in this bul- 
letin, may be grouped into eight species and subspecies, as follows: 
Triticuin mdgare, T. conqmctitm^ T. durum, T. turgldimi, T. poloni- 
cimi., T. Kpdta., T. dicoccnim^ and T. monococciiiii. Only T. vulgare^ 
T. polonicum, and T. monococcum are considered to be good species- in 
all classifications. The other five are generally considered as subspe- 
cies of T. vidgare^ though T. coriipacturu is sometimes not even ele- 
vated to that rank. In this bulletin they will all be referred to as 
though they were distinct species. The chief characters of these 
groups of wheats will now be described, with special reference to their 
importance in wheat improvement. 

COMMON BREAD WHEATS [TrUicum vulgare). 

This is of course the most valuable and widely distributed group of 
wheats in the world, and is represented l)y a greater number of varie- 
ties than all other species taken together. Nevertheless a number of 
veiy important qualities can be found only among varieties of the 
other species. 

The characters of this group, both l^otanical and agricultural, are 
well known. The heads are long in proportion to thickness, as com- 
pared with those of some other groups. The}^ are broader in the plane 
of the rows of spikelets, as a rule, and narrower on the sides of the 
fui-row between the rows; taper toward the apex, but may be very 
blunt or even thicker above; are usually looseh^ formed comparatively^ 
bearded or bald, and usually possess smooth chaff, but may Ix^ velvety. 
The spikelets, or meshes, as they are popularly called, generally con- 
tain three grains, but sometimes two and rarely four. The empty 
glumes or outer chaff of the spikelets are slightly keeled above and 
merely arched below. The -stem of th(^ plant is usually hollow, l)ut 
occasionally somewhat pithy within and varies greatly in strength and 
height in different varieties. The leaves also vary in character, but 
are rarel}^ as wide as those of the durum and poulard groups, and are 
velvety in only a few varieties. 

1 Kornicke, Fr., and Werner, H. Handbuch des Getreidebaues, 1885. 



27 

The species is usually divided into a number of botanical subspecies 
and varieties, based upon the presence or absenc-e of beards, nature 
and color of the chatf, color and qualit}' of the grain, etc. For our 
present purpose, however, 'it will be more useful to consider that there 
are live great suVjdivisions of the species, based not upon botanical 
characters, but upon characteristics induced by influences of environ- 
ment, as follows; (1) Soft Winter wheats, (2) Hard Winter wheats, 
(3) Hard Spring wheats, (-i) White wheats, and (5) Early wheats. 

The location of these groups in the United States has already been 
pretty well stated in the descriptions of our wheat districts. Their 
distribution throughout the world is approximately as follows: (1) The 
soft winter wheats, varying in color of grain from aml)er to white, are 
produced under the influences of considerable moisture and mild, even 
temperatures, and are distributed in the Eastern United States, west- 
ern and northern Europe, Japan, and in portions of China, India, 
Australia, and Argentina. (2) The hard winter wheats are red-grained, 
usuall}^ bearded, possess a relatively high gluten content, and are 
more limited in their distribution. They are grown usually on black 
soils and under the influences of a climate characterized by extremes 
of temperature and moisture, but especially by dry, hot summers. 
They are found chiefly in the States of Kansas, Nebraska, Iowa, Mis- 
souri, and Oklahoma in this country, in Hungary and Roumania, in 
southern and southwestern Russia, and to some extent in northern 
India, Asiatic Turkey, and Persia. (3) The hard spring wheats are 
also red-grained and rich in gluten content, and are adapted to con- 
ditions of soil and climate identical with those just mentioned for hard 
winter wheats, with the exception that the growing season is shorter 
and the winters too severe for winter varieties. They are found in 
central and western Canada, our Northern States of the plains, east 
Russia, and western and southern Siberia. (4) The white wheats are 
soft and very starchy, l)ut possess grains a little harder and nuu-h 
drier than those of the soft winter wheats. They are either fall or 
spring sown, and are sometimes sown at both seasons in the same 
localit}'. They are grown chiefly in the Paciflc coast and Rocky 
Mountain States of this CQuntry, in Australia, and in Chile, Turkestan, 
and the Caucasus. (5) The early wheats are soft or semihard and 
generally amber to red in color of grain, but are distinguished from 
oth(n' groups chiefly in their ability to ripen early. They are found 
in Australia and India, ai-e represented by a very few varieties in the 
Southern States of this country, and include some of the dwarf wheats 
of Ja[)an. 

The varieties of this species naturally include the most diverse char- 
acters, because of their cultivation under so many diverse conditions. 
Their greatest characteristic as a whole, how(>vcr, is. of course, the 
well-known and long-esta))lishe(l (juality of their grain for the produc- 



28 

tion of bread flour, for which reason the term ''bread wheat" is 
usually applied to them. Nevertheless, it should be noted that the 
difference between the best and poorest sorts of this group for bread 
making is full}' as great and sometimes greater than between the for- 
mer and some v^arieties of other groups. The hard, red-grained 
varieties are by far the best both in food content and for our present 
system of roller milling. They include the Fifes, Velvet Blue Stem, 
Turkey, Mediterranean, and Fulcaster, of this country and Canada; 
the Ghirkas, Ulka, Crimean, and Buivola, of Russia; and the Theiss 
and Banat, of Hungary and Roumania. On the other hand, the white 
wheats and soft winter wheats give the best success in the manufac- 
ture of crackers. Several of the most popular breakfast foods are 
also made from white wheats. In a few instances macaroni is made 
from the hard spring wheats and the white wheats, but not exten- 
sively. No varieties of the bread-wheat group are well adapted for 
this purpose. 

The special qualities that are found in varieties of this group may 
be summarized as follows: 

(1) Excellence of gluten content for bread making. 

(2) Excellence of certain varieties for cracker making. 

(3) Yielding power of certain sorts. 

(4) Rust resistance in some varieties. 

(5) Hardy winter varieties. 

(6) Resistance to drought (in some varieties). 

(7) Early maturity (in some varieties). 

CLUB OR SQUARE HEAD WHEATS {T. COmpactum). 

By most writers this is not even ranked as a subspecies, but the 
different varieties certainly form an isolated group which is quite 
complete in itself and distinct from all other wheats, and which will 
therefore be considered here as a distinct species. The various varie- 
ties are commonly known under the names "club" or "square head". 
In this species the plant is verv erect, with stiff", usually rather short, 
culm, attaining an average height of probably little more than 2 
feet. The heads are extremely short as a rule, and often squarely 
formed, in some varieties much broader and flattened on the furrow 
side, usually thicker at the apex than at the base, commonly white but 
sometimes red, bearded or bald, the bearded varieties usuall}^ being 
native in hot countries. The spikelets are set extremely close together, 
often standing almost at right angles to the rachis (stem), three or four- 
grained, sometimes with four grains nearly throughout the entire head. 
The outer and inner chaff' are much the same as in the bread wheats. 
The grains are usually short and rather small, white or red, often 
boat-shaped, and occasionally appear much like those of naked barley. 

The peculiar structure of the head in this species allows the varie- 
ties to be comparativelv large yielders, which is naturalh' their most 



Bui. 24, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



Plate VI. 




Fig. 1.— Combined Harvester-thresher at work near Walla Walla, Wash. 
(Photographed by A. B. Leckenby. ' 




Flo. 2. -Harvesting with the Wide-cut Binder near Colfax, Wash. 'Original. 



29 

important quality. They are very deceptive in tliis regard, the short- 
ness of the head leading one to suppose at hrst that it can not contain 
so many grains as are present in reality. The chati' is usually very 
tenacious, so that these wheats may be harvested long after ripening 
without loss from shattering. This is especially true of varieties 
grown in California and Washington. Having short, stiff straw, these 
wheats also usually stand up well, any damage from lodging being 
quite rare among them. Besides producing the class of tlours desired 
in certain localities, club varieties are very good for cracker making 
and for the more starchy kinds of breakfast foods. They are grown 
either as spring or winter varieties except in Turkestan, where the 
winters are too cold for fall sowing. Being grown in dry, hot regions, 
they are usually rather drought resistant. 

Club wheats are at present cultivated chiefly in the Pacific Coast 
and Rocky Mountain States of this country, in Chile, Turkestan, and 
Abyssinia, and to a slight extent in Switzerland, Russia, and a few 
other districts of Europe. The special qualities of the group are as 
follows: 

( 1 ) Great yielding power. 

(2) Stiffness of straw. 

(3) Freedom from shattering. 

(4) Early maturity (in some varieties). 

(5) Drought resistance (in some varieties). 

(6) Excellence of certain varieties for cracker making and breakfast foods. 

POULARD WHEATS {T. turgidum). 

This group of wheats is usually classed as being quite distinct from 
the durum (T. durum) group, the two ranking as subspecies of T. 
vulgare. But as a matter of fact there are intergrading varieties 
which bring them as close together as are the club wheats and common 
bread wheats. They will both be considered here, like T. co7nj?actum, 
as distinct species. 

The poulard wheats are usually rather tall, with broad, in most varie 
ties velvety, hairy, or often glaucous leaves. The stems are thick 
and stiff, and sometimes pithy within. Heads long, often squarely 
shaped, with long beards, that are white, red, or bluish red in color, 
or sometimes black. Spikelets two to four-grained, and arranged 
rather compactly. Outer chaff' strongly and sharply keeled. Grains 
large, proportionally shoit and rounded, sometimes ahnost semicircular 
in middle cross section, rather hard and glutinous, light yellowish red 
in color, sometimes nearly white, and becoming glassy in varieties 
allied to the durum group, or on growing in certain soils. 

The name poulard is most commonly applied to these wheats. In 
Europe they are sometimes called English wheats, a very misleading 
name, as they are really little grown in England. On th(> other hand 
the few varieties that have been grown there are known as rivet 



30 

wheats. A name often used in Germany is hauchigerWeizen^ ^ndi a 
French name of corresponding meaning occasionally used is hU 
Ijetanielle. 

The wheats of this group are used sometimes in the manufacture 
of macaroni and other pastes. They are also occasionally used in 
bread making, but are more often employed for mixing with common 
bread wheats in grinding in order to give the quality of flour that is 
desired in the French markets. 

To a small section of this species, having compound or branched 
heads, some have given the separate name of composite w^heats {T.com- 
2?ositum). Some well-known varieties of this section are Seven-headed, 
Wonder Wheat, Hundred Fold, and Miracle. It should be noted, 
however, that the group of emmers {T. dicoccum) includes several 
varieties with compound heads similar to these. Many facts known 
in connection with the existence of these closely allied forms, together 
with that of the intergrading sorts between the poulards and durums, 
afford strong evidence of the occurrence of natural hybrids among 
the varieties of these three groups. 

The poulard wheats are native usually in hot, dry regions, and are 
therefore often rather drought resistant, but not so much so probably 
as the durums. Many of the varieties are also very resistant to orange 
leaf rust. These wheats are grown chiefly in France, Egypt, Italy, 
Turkey, Greece, southern Russia, and other districts bordering the 
Mediterranean and Black seas. In this country they are only rarely 
grown; so far, in an experimental way. Special qualities of value to 
be found in this group are: 

(1) Excellence of certain varieties for making macaroni. 

(2) Resistance to orange leaf rust. 

(3) Resistance to drought. 

(4) Stiffness of straw. 

DURUM WHEATS ( T. clurum) . 

As already stated, this group of wheats is rather similar to the 
poulard group. As a rule, however, the heads are not so thick and 
the grains are longer and much harder. The plants are rather tall, 
w ith stems either pithy within, or hollow with an inner wall of pith, 
or in a few varieties simply hollow as in the common bread wheats. 
The leaves are usually smooth, but have a hard cuticle, and are almost 
always resistant to orange leaf rust. The heads are rather slender, 
compactly formed, occasionally very short, and always bearded, with 
the longest beards known among wheats; spikelets two to four- 
grained. The outer chaff is prominently and sharply keeled, and the 
inner chaff somewhat compressed and narrowly arched in the back. 
The grains are usually very hard and glassy, sometimes rather trans- 
parent, 3^ellowish white in color, occasionally inclining to reddish, and 



51 

l)ioportionally rather long-. In the variety Arnautka the grains are 
ahnost or fully as large as those of Polish wheat, and are sometimes 
actually mistaken for the latter. 

The varieties of this group are generally best known as the durums. 
In Europe they are often called, and correctly so, simply hard wheats. 
They are the hardest-grained wheats that are known. The Fifes, 
Velvet Blue Stem, Turkey, and others of that class usually called hard 
wdieats in this country are not, strictly speaking, hard wheats at all 
when compared with these. On account of the resemblance of the 
heads of these wheats to those of barley they are sometimes called 
barley wheats or Gerstenimizen. 

Durum wheats are particularly sensitive to changes of environment, 
and quickly deteriorate when grown in a soil or climate to which they 
are not well adapted. Such a change of conditions may be encountered, 
too, within the distance of a few miles. For example, it is well under- 
stood in south Russia that the excellent variety Arnautka gives the 
best results only when grown within a very limited area bordering 
the Sea of Azov. So also the best Kubanka is found east of the Volga 
on the border of the Kirghiz Steppes. In the Caucasus this variety 
has actually developed into a red winter wheat, though the original 
is a yellowish-white spring wheat. 

The durum group furnishes the great bulk of the world's supply of 
macaroni wheat, though a considerable amount of these pastes is made 
from poulard and Polish varieties and a still smaller proportion from 
the common bread wheats. There is now not the least doubt that 
some if not all these durum sorts used for macaroni can be successfully 
grown in this country, thus adding immensely to the profits of our 
wheat industry. The success that has attended the trials of the variety 
Nicaragua in Texas has already conclusively proved the point. At the 
same time the idea that these wheats can not be successfully used for 
bread has never yet been shown to be more than mere assumption. Sev- 
eral mills in this country have successfully ground them, and i n southern 
Russia, where milling has developed to a high degree of perfection, it 
is no longer an experiment. In that i-egion durum wheat has become 
actually the most popular for bread making, though it is usually mixed 
with a small per cent of ordinary red wheat before grinding. In France 
there is an increasing demand for durum wheats for all ])urposes. 

Durum wheats are adapted for soils rather rich in nitrogenous 
matter but somewhat alkaline, and give the best results in a very hot, 
dry climate. They are, theri>fore, quite drought resistant. Almost 
all varieties are adapted only for spring growing except in mild lati- 
tudes. Tii<> young plants both of this group and the poulard group 
arc very light green in color at tirst and grow up rapidly. They are 
grown in Spain (where they predominate over all other groups) and 
other Mediterranean countries, in south and east Russia, Asia Minor, 



32 

and to some extent in Mexico, Chile, and Arjj^entina. In this countiy 
one variety, Nicaragua, is grown to a limited extent, chiefly in Texas. 
The special qualities to be obtained in this group are briefly: 

(1) Excellence of gluten content for making macaroni and other pastes. 

(2) Resistance to drought. 

(3) Resistance to orange leaf rust. 

POLISH wHE.\Ts ( T. polonicum). 

This group is considered by all writers to belong to a distinct species. 
Though there are several subspecies and varieties, apparently only one 
variety. White Polish, is very widely known. The plant is usually 
rather tall, with stems smooth and more or less pithv witJiin. It does 
not stool extensively. The heads are extremely large and loosely 
formed, and before ripening are bluish-green in color. A special pecu- 
liarity of this species is the rather long, narrow, outer chafi'. papery in 
structure, and standing out slightly from the head, instead of being 
rigid and closely applied to the spikelets, as in other wheats. The 
grains are of great size when normal, proportionately quite long, yel- 
lowish-white in color, and very hard. The name Polish wheat is univer- 
sally applied to this species, though for what reason it is not clear. 
There is no evidence at all that it originated in Poland, and in fact it has 
been very little grown in that region. It is more probable that its 
native home is some portion of the Mediterranean region. A red win- 
ter wheat ofrown rather extensivelv in Poland and southwest Russia and 
also called Polish wheat, should not be confused with this group, as it is 
radically dilierent, being one of the bread wheats. Other names have 
been given to this species but they are quite local in their use; such are 
Giant rye, Astrakhan wheat, Jerusalem rj^e, etc. 

In almost all of the few cases where Polish wheat has been tried in this 
country it has proved a success from both the standpoint of yield and 
quality of the grain. But it seems never to have occurred to anyone 
to make use of the wheat for the production of Auierican macaroni, 
though no doubt it would be excellent for that purpose, and a great 
demand for its increased production could thus be created. As it is, 
there is not sufficient incentive to the farmer for growing this wheat, 
since it is not well adapted for bread making if used alone. 

Though requiring considerable moisture at seedtime. Polish wheat is 
admirably adapted for cultivation in arid districts; in fact, it produces 
the best quality of grain when grown under arid conditions. It is also 
somewhat resistant to orange leaf rust, but not so valuable in this 
respect as the durum wheats. Varieties of this species are grown 
chiefly in Italy. Spain, and other portions of the Mediterranean region, 
and in southern Russia and Turkestan. They are also said to be culti- 
vated to some extent in Brazil. 



33 

The special qualities of value belonging to Polish wheat are similar 
to those of the durum group, and are as follows: 

(1) Quality of gluten content for making macaroni. 

(2) Resistance to drought. 

(3) Eesistance to orange leaf rust. 

SPELT (T. spelta). 

This and the two following species are in several respects very dif- 
ferent from any of the preceding groups. They are also not widely 
cultivated, although more commonly grown than Polish wheat, and are 
used only to a very limited extent for human food. Nevertheless, in 
the intercrossing of wheat groups for the improvement of our bread 
wheats some very valuable qualities may be obtained from varieties of 
these species. 

The varieties of this group are called spelt in English, Sj)eh in Ger- 
man, and ejpeautre in French. In Germany the old name Dinkel is 
also sometimes applied. The varieties often called spelt in this coun- 
try and Russia are not spelt, but emmer (T. dicoccurii). 

The spelt plant (Plate VII) grows to the average height of wheat, 
or perhaps a little higher, and possesses a hollow stem. The leaves 
are of ordinary size, usuall}'^ smooth, but sometimes with scattering 
hairs; heads loose, narrow, and rather long, bearded or bald, espe- 
cially characterized by a very brittle rachis, allowing them to be easily 
broken in pieces in thrashing. The spikelets are usually far apart in 
the head, arched on the inner side, and contain usually two grains; 
outer chaflf oval, four-angled, boat-shaped, and only slightly keeled; 
grains light red in color, somewhat compressed at the sides, with a 
narrow furrow, the walls of the furrow flattened, and with sharp 
edges. The grain is always held tightly within the chatf, and can not 
be hulled in thrashing. 

Spelt is used very little for human food, but is generally fed to stock. 
It is very important, however, for certain portions of our country, at 
least, to obtain for the bread wheats the particular quality of this 
group of holding the grain tenacioush'. This can readil}' be done, as 
the Garton Brothers have amply demonstrated in England, by inter- 
crossing varieties of the two groups. For certain varieties that would 
otherwise be of great value in the Pacific Coast and Rocky Mountain 
States such an improvement of preventing shattering at harvest is the 
most important that can be made. The few varieties possessing this 
(jualit}^ that are now grown in these districts are sometimes not desira- 
ble in other respects. At the same time complaint is oft(Mi made that 
c(M-tain introduced varieties which are most excellent from the stand- 
l)()int of yielding capacity and hardiness are rendered worthless because 
of the irreat loss from shatterino-. It has also been observed bv certain 
experimenters that the (juality of constant fertility, or of producing 
487'J— No. 24 3 



34 

"well-filled" heads, is greatly increased by the introduction of the 
spelt element. No doubt we very little realize the loss in yield that 
is simply the result of the inability of the variety to fill out its heads. 

There are both winter and spring varieties of spelt, and some of the 
former are very hardy. Certain varieties are also rather drought 
resistant, but nearly all sorts are more or less susceptible to rust 
attacks. It is in just such cases as that of the use of spelt varieties 
in intercrossing with bread wheats that the greatest of judgment must 
be exercised because of the presence of undesirable as well as desira- 
ble qualities. While the experimenter is endeavoring to secure the 
qualities of nonshattering, drought resistance, etc. , it is equally impor- 
tant to select from the progeny of such crosses in such a way as to 
eliminate the characteristics of rust liability and brittleness of the 
head. Here also is shown emphatically the advantage of the practice 
of composite crossing (to be discussed further on), as in such case the 
variation induced is so great that there are almost certain to be indi- 
viduals present among the sporting ofispring which possess the desired 
qualities without having preserved the undesirable ones. 

Spelt is chiefly grown in Germany, Italy, Spain, France, and Swit- 
zerland, and perhaps to a small extent in Brazil. It is not grown in 
this country except mainly in an experimental way. Summarized, 
the desirable qualities found in the spelt group are: 

(1) Power of holding the grain in the head. 

(2) Constancy in fertility. 

(3) Hardiness of certain winter varieties. 

The undesirable ones are: 

(1) Brittleness of the head. 

(2) Rust liability. 

EMMER {T. dicoccuni). 

This species has no English name, but is often incorrectly called 
spelt in this country. The German name is Emmer and the French 
amldonnier. As the German name is best known and easily pro- 
nounced, it should be at once adopted with us, and the name spelt 
applied where it properly belongs. In Russia, where the group is 
well represented, it goes by the name of polha, which name is invari- 
ably translated spelt. But either the Russians wrongly apply the 
name polba or this is an incorrect translation. As a matter of fact, 
very little if any true spelt is grown in Russia, though a rather large 
quantity of emmer is produced each year. 

The plants of this species are pithy or hollow, with an inner wall of 
pith; leaves sometimes rather broad, and usually velvety hairy; heads 
almost always bearded, very compact, and much flattened on the two- 
rowed sides. The appearance in the field is therefore quite difierent 
from that of spelt. The spikelets (that is, the unhulled grains as they 



Bui. 24, Div. Vtg. Phys & Path., U. S Dept. of Agriculture. 



Plate Vll. 




35 

come from the thresher), however, look considerably like those of 
spelt, but difi'er principally in the presence always of a short pointed 
pedicel. This pedicel, which is really a portion of the rachis (stem) 
of the head, if attached at all to the spelt spikelets, is always very 
blunt and much thicker. Besides, the emmer spikelets are flattened 
on the inner side, and not arched as in spelt, so that they do not stand 
out from the rachis as the spelt spikelets do, but lie close to it and to 
each other, forming a solidly compact head. The spikelets are usually 
two-grained, one grain being located a little higher than the other. 
The outer chafi' is boat-shaped, keeled, and toothed at the apex. The 
grain is somewhat similar to that of spelt, but is usually harder, more 
compressed at the sides, and redder in color. 

' For the production of new varieties by hybridization emmer has 
qualities similar to those of spelt, but still more valuable. At the 
same time emmer, besides possessing harder grain, is more resistant 
to drought, and usually rather resistant to orange leaf ru.'^t. It is well 
adapted for cultivation in the northern States of the Plains and has 
already proved very valuable as a hardy forage plant in that region, 
besides giving a good yield of grain per acre. Almost all varieties 
are spring grown. Of other countries emmer is chiefly cultivated in 
Russia, Germany, Spain, Italy, and Servia, and to some extent in 
France. The emmer of this country is descended from seed originally 
obtained chiefly from Russia, where a considerable portion of the food 
of the peasants of the Volga region is a sort of gruel ("kasha") made 
from hulled and cracked emmer. 

The desirable qualities furnished by this group of wheats are: 

(1) Power of holding the grain in the head. 

(2) Drought resistance. 

(3) Resistance to orange leaf rust. 

The undesirable qualities are: 

(1) Brittleness of the head. 

(2) Adaptability only for spring sowing. 

EiNKORN (T. monococcum). 

This species of wheat is very distinct from any of the others, though 
the heads resemble those of emmer somewhat. It has no F^nglish 
name, but is called Einkorn in German and erigrain in French. The 
German name is adopted here. 

Einkorn (Plate VII) is a short, thin, and narrow-leaved plant, which 
presents a peculiar appearance in the Held. It seldom reaches a height 
of more than 3 feet. The stem is iiollow, thin, and very stitt". The 
leaves are usually quite narrow, soinetimes hairy. Those of the young 
plant are sometimes bluish-green, and after flowering the plant becomes 
yellowish-green. Portions of the stem may also be brown. The 
heads are slender, narrow, very compact, bearded, and much flattened 



36 

on the two-rowed sides, and always stand erect, even Avhen ripe, but 
break in pieces easily. The spikelets are flat on the inner side, or 
form a concave surface with the projecting edges of the outer chaff. 
They are arranged very compactly in the head and are usually one- 
grained, except in the variety Engrain double (Plate VII), where 
they possess two grains. The outer chaff is deeply boat-shaped and 
rather sharply keeled, the keel terminating in a stiff* tooth. The 
grains, which are tightl}' inclosed in the spikelet, are light red and 
extremeh' flattened, becoming thus bluntly two-edged and possessing 
an exceedingly narrow furrow. 

This species is at present but little improved over the original wild 
form, and only a few varieties have been developed. Nevertheless 
some of the most valuable qualities maj^ be expected from these varie- 
ties if they can be successfully employed in hyl)ridization experiments. 
They are among the hardiest of all cereals and seem to be constant in 
fertility, and in the writer's experience are absolutel}^ proof against 
orange leaf rust. Einkorn is entirely unknown in this country, except 
among a few experimenters, but is grown to a limited extent in Spain, 
France, Germany, Switzerland, and Italy. The two chief varieties 
are common Einkorn and Engrain double. 

The valuable qualities to be obtained in this species may be summa- 
rized as follows: 

( 1 ) Power of holding the grain in the head. 

(2) Resistance to orange leaf rust. 

(3) Hardiness. 

(4) Resistance to drought. 

(5) Stiffness of straw. 

An undesirable quality is: 

(1) Brittleness of the head. 

GEOGRAPHIC GROUPS OF WHEATS. 

From the description of the different natural groups just given and 
the statements concerning their geographic distribution, it may be 
inferred that the localities as well as the natural groups might also 
be given from which particular qualities in wheat can be obtained. 
This can be done, but not with the completeness that could be desired, 
as it is not yet accurately known what kinds of wheat grow in all 
regions of the world. However, the matter may be stated approxi- 
mately and briefly as follows: (1) White Avheats containing much 
starch are grown in the Paciflc Coast and Kocky Mountain States of 
this country, in Chile, in Turkestan, and to some extent in Australia 
and India. (2) Amber or reddish-grained wheats, also starchy, are to 
be found chiefly in the Eastern States of this country, in western and 
northern Europe, and to some extent in India, Japan, and Australia. 
( 3 ) Large proportions of gluten content of the quality considered to 



37 

be necessary for making the best bread are found in the red wheats of 
Canada and our Northern and Middle States of the Plains, in eastern 
and southern Russia, in Hung-ary and Roumania, and in southern 
Argentina, (-i) Resistance to orange leaf rust is to be secured in the 
bread wheats of southern Russia (particularly in the Crimea and 
Stavropol government), in the poulards, emmers, and einkorn of the 
countries bordering the Mediterranean and Black seas, and in a few 
varieties in Australia. (5) Large gluten content of the quality 
necessary for making the best macaroni is furnished by the durums, 
poulards, and Polish wheat of Algeria, Italy, Spain, and especially of 
the northern shores of the Black and Azov seas in Russia, and to a 
limited extent in the State of Texas in this country. (6) Stiffness of 
straw, preventing the lodging of the grain, is found in the einkorn 
and some of the spelts, durums, and poulards of the Mediterranean 
countries, and in the dwarf bread wheats of Japan, and some of the 
club wheats of our Pacific Coast States, Turkestan, and Australia. 
(7) Great yielding power, at least in proportion to the length of the 
head, is obtained in the club wheats of the Pacific Coast States of this 
country and Chile, and Turkestan. (8) The quality of holding the 
grain, or nonshattering, is found in the club wheats of the Pacific Coast 
States, Chile, and Turkestan, and in all the spelts, emmers, and einkorn 
of east Russia, Germany, and the Mediterranean countries, and to a 
limited extent in the emmers of our northern States of the Plains. 
(9) Constant fertilit}^, so far as known at present, is probably best 
obtained in the spelts of Germany and Southern Europe. (10) Early 
maturity is found to a limited extent in some of the bread wheat 
varieties of Australia and India, and in the dwarf wheats of Japan. 
(11) Resistance to drought and heat is best secured in the conunon 
red wheats and durums of south and east Russia, and the Kirghiz 
Steppes, the durums of the south Mediterrean shore, and both the 
bread wheats and durums of Turkestan. (12) Resistance to drought 
and cold is found to the greatest degree in the red winter wheats of 
East Russia. 

IMPROVEMENTS ACCOMPLISHED. 

Looking to the future, the possibilities for wheat improvement 
appear to be unlimited, and it is with these that we are of course more 
directly concerned at present. It will be of interest, however, to con- 
sider briefiv some of the areat cliano(>s for the better that have already 
been made in the wheat industry of this country during its short his- 
tory. Some of tliese changes have been accomplished in line with 
similar ones in othei- countries, and have been coincident with improve- 
ments in the milling process or with the demands of consumers for 
greater variety in food, but in th(^ main they have followed as a nat- 
ural result of the development of the country. As wheat is not native 



38 

in the United States, necessarily all seed was originally brought from 
other regions. At first, the territor}^ being limited and the demands 
of the people comparatively simple, ver}?^ few varieties were sufficient; 
but as the country rapidly developed and new territory was from time 
to time added and thrown open to settlement, new and varied condi- 
tions of soil and climate were encountered, and to meet the require- 
ments of these new conditions other new and different varieties 
became necessary in order for the best success. 

INTRODUCTION OF NEW VARIETIES. 

A full history of the introduction of new varieties of wheat into this 
country, and from one section of the country to another, Avould be a 
matter of much interest but can not be attempted here. Only a few 
of the most important instances will be mentioned — those that mark 
real epochs in the development of our wheat industiy, and have in cer- 
tain localities entirely revolutionized wheat culture. 

By far the most important among the earliest varieties introduced is 
the Mediterranean wheat, obtained first in 1819 from the islands of the 
Mediterranean Sea. At various times after that date this Department 
secured seed of the same variety and distributed it to all parts of the 
country. It soon met with favor everywhere. It is a hard}^, bearded 
variet}'^, productive, and producing a large red grain of good milling 
quality. But more than all this it was found to be quite resistant to 
rust and to damage by the Hessian fly, two enemies of the wheat crop 
which had already begun to be very much dreaded. This wheat has 
maintained its excellence through all decades since, and is to-day one 
of the most popular varieties in certain States, particularh" Texas. It 
has also been used as a parent of several very valuable hybrids. 

A most interesting example of improvements that are possible in the 
adoption of varieties best adapted to a particular region is found in 
the Fife wheats of Canada and the Northern States of the Plains. 
These varieties, which have become the basis of the great wheat and 
flour production of the Northwest, originated, according to the Cana- 
dian Agriculturist of 1891, in the following manner: 

Mr. David Fife, of the township of Otonabee, Canada West, now Ontario, pro- 
cured through a friend in ( ilasgow, Scotland, a quantity of wheat which had been 
obtained from a cargo direct from Dantzic. As it came to liand just before spring 
seed time, and not knowing whether it was a fall or spring variety, Mr. Fife con- 
cluded to sow a part of it that spring and wait for the result. It jjroved to be a fall 
wheat as it never ripened, except three ears, which grew apparently from a single 
grain. These were preserved, and although sown the next year under very unfavor- 
able circumstances, being (juite late and in a shady place, it proved at harvest to be 
entirely free from rust when all wheat in the neighborhood was badly rusted. The 
produce of this was carefully preserved, and from it sprang the variety of wheat 
known over Canada and the Northern States by the different names of Fife, Scotch, 
and Glasgow. 

If the above is an accurate statement of the introduction of Fife 
wheats, indications are rather strong that the}' are of Russian origin, 



39 

judging from the description of the grain and source of the cargo, in 
connection with the present similarity of these wheats to Russian 
varieties. Their subsequent history in the Northwest and the impetus 
given to the wheat industry of that region through their cidtivation 
are well known to agriculturists generally. Various strains have been 
developed till there are now a dozen or more so-called varieties in use. 
They are red, hard-grained wheats (as we use the term) similar to the 
Ghirkas of the Volga region, yield fairly well, and produce flour of 
excellent quality. 

In Michigan there has been an energetic movement for a decade or 
longer to obtain hardy winter sorts, which has resulted in a great 
improvement not only for that State but for adjoining territory. The 
millers of the State have especially been active in this movement and 
the matter has been frequently a prominent topic of discussion at the 
meetings of the State Millers' Association. Budapest from Hungary 
and Dawson's Golden Chafl' from Canada have been introduced and 
become favorite varieties. Another variety, Theiss, introduced from 
Hungary, has obtained a well-merited reputation as a hardy, red 
winter sort in the North Central States and as far west as Kansas. It 
has, however, not even yet received the attention that it should have. 

Perhaps the most remarkable development in wheat culture in this 
country has been made in the Middle States of the Plains, in what we 
may now call the Hard Winter Wheat district, all brought about 
through the introduction of the hardy, red-grained wheats. Twenty- 
five years ago very little hard wheat was grown in this region, the 
seed being brought by the early settlers from States farther east, 
where soft wheats were chiefly cultivated. Also, spring varieties 
formed the basis of a large proportion of the wheat production. But 
the spring wheats were severely rusted, injured by drought because 
of late maturity, and in some seasons almost wholly destroyed by 
chinch Inigs, while the soft winter sorts, such as White Michigan and 
Poole, also rusted badly and were not able always to stand the winters. 
For some time these defects were overcome in great measure by the 
use of the variety Odessa, popularly called "-Grass'' wheat in some 
localities, which is probably equivalent to the variety LTlka of south- 
ern Russia. It is hardy, red-grained, rather rust resistant, and has the 
additional advantage of being adapted for cither autunm or spring 
sowing. A little later, the well-known vai-iety Fultz also became 
quite popular in the West, as it is still in the greater portion of the 
United States. 

But th(>, variety which more than all others tinally completely 
changed the status of wheat culture in this district, is that which is 
commoidy but unfortunately known as Turkey. It is a bearded, hard 
red wheat of the highest class, coming originally from the Crimea and 
other portions of Taurida in southern Russia, and not from Turkey as 
the name would imply. Within a very small area in Kansas, Turkey 
wheat has been grown al)out twenty-five years, but its merits have 



40 

become generally known only during the last twelve or fifteen years. 
It is now a favorite variety in the middle Great Plains. B3' the use of 
this variet}^ autumn sowing is now made practicable in most seasons 
to the northern limit of the district, and the winter-wheat flour from 
this region has obtained a reputation for quality of the very best, and 
distinctively its own, in the foreign markets. At the same time there 
is no longer so much damage resulting from the attacks of rust and 
chinch bugs. As it is also one of the most drought-resistant sorts, it 
has made it possible to extend the winter- wheat area farther westward 
as well as northward. 

In a large part of the Pacific coast region, including the Palouse 
country, the improvements which have resulted in such large yields 
and great profit in certain localities were made chiefly through the 
introduction of club wheats, which are very productive, hold the grain 
in the head, and are in other regards well adapted to the conditions of 
the region. One or more of these wheats came originally from Chile, 
and others probably from Australia and France, but the origin of 
many of them is not accurately known. Two other varieties, not club 
wheats, namely. Australian and the Palouse Blue Stem, are also two of 
the most valuable wheats of this district and probably belong to the 
Purple Straw group of Australia. 

In southern California and the Irrigated Wheat district the variety 
Sonora has had the greatest influence in the development of wheat 
culture. It is a white-grained sort with reddish, velvet chafl', but the 
grains are a little harder than those of the club type and better adapted 
for export. It came originally from the State of Sonora in Mexico. 

Among later introductions is the variety called Nicaragua, a durum 
wheat, alread}^ discussed in another part of this bulletin, which is 
likely to take a considerable part in the future wheat production of 
this country, both because of its adaptation — as is true of all durum 
varieties — to the hot, dry summers of the southwestern Great Plains, 
and because of its suitability for the manufacture of macaroni. No 
facts concerning the origin of this variety are at present known to the 
writer, though one would infer from the name that it came from 
Nicaragua, and it is true that varieties of the same group are known 
in that country. It has been known in Texas for many years, and its 
use has made it possible to grow wheat in portions of that State not 
before successful in wheat growing. A variety similar to this one, 
called Wild Goose, is grown to a very limited extent in North Dakota, 
and probably came originally from southern Russia. It is also likely 
to be of value for the production of macaroni, though it seems to be 
somewhat inferior to Nicaragua. 

WORK OF THE DEPARTMENT. 

In connection with the discussion of the introduction of varieties, it 
is hoped that it will he of interest to give an account of the experi- 
ments made by this Department with wheats from all parts of the 
world. Though the aim in beginning these experiments, as already 



41 

stated, was primarily to test rust resistance, the work naturally soon 
developed into a study of the characteristics in general of the varieties 
of different natural groups of wheats, and of groups considered geo- 
graphically, and some most interesting facts were thus obtained which 
will be of great value in the work of wheat improvement. In fact, 
many statements made in the foregoing discussion of the " Sources for 
desiral)le qualities" are based upon the results of these experiments. 
Varieties were obtained from every wheat country of the woi'ld, 
aggregating about 1,000 rather distinct sorts in all. The manner of 
securing these wheats, and the time and labor thus involved, together 
with the difficulties of nomenclature arising from the confusion of 
varietal names which prevails generally, have all been discussed in a 
former bulletin on Cereal Rusts of the United States, and need not be 
referred to here. The varieties were grown one year in Maryland and 
most of them one year in Kansas, while about 300 of them were grown 
two years in Kansas, or three years in all; that is, during 1895, 1896, 
and 1897, During the same time a number of the varieties, especially 
from Russia, Siberia, Japan, and Argentina, were tested by other 
parties in cooperation with the Department, in other localities, viz, in 
Michigan, Wisconsin, Indiana, Tennessee, and Colorado; and in the 
case of a few of these, the experiments have since then been repeated 
in Colorado, Kansas, and Nebraska, 

In conducting these experiments all the principal characteristics of 
the wheat plant, as shown in its different stages from that of the young 
plant to harvest time, were studied, though complete notes can not be 
given for every variety. These features include in a general way 
(1) the character of the young plant; (2) hardiness, including resistance 
to rust, drought, and cold; (3) character of the head; (1) character of 
the grain; and (5) time of maturity. Field experiments alone do not 
show those qualities of the grain which indicate the value of the variety 
for different uses, and which are after all more important than any 
others; though it must be remembered that certain characteristics of 
the growing plant often indicate quite correctly what these qualities 
will be. Therefore chemical analyses have been made of a large 
number of representative varieties, and for many of them the absolute 
weight and specific gravity of the grain have also ])ecn determined. 

As would be expected, a large number of the varieties either proved 
to be entirely unsuited to the conditions in this countrj^ or were found 
to be in other respects undesirable sorts. It was the purpose from 
the start to discard gi'aduallv all varieties that seemed to be uhjible to 
adapt themselv(!s to their new environment. During the tirst year oi 
the experiments at (iarrett Park, Md,, many of them were planted so 
late, on account of their late arrival in this country, that much allow- 
ance must be mad(^ for their behavior in comparison with others 
which were sown in good season. In other respects the trial for that 
year was very satisfactory, and afforded an excellent opportunity of 
c()m])iiring the behavior and <|ualities of a large number of varieties 
under average conditions. 



42 

But the larger portion of our area most important in wheat pro- 
duction lies much farther westward than Maryland and possesses a 
very different soil and a climate characterized by great extremes of 
drought, cold, and heat. At the same time it is manifestly desirable 
to search particularly for varieties adapted to such extreme condi- 
tions for two reasons: (1) It is found that as a general rule sorts 
which are able to withstand the most rigorous extremes of climate are 
also of the class which makes the best quality of bread and macaroni, 
the two principal purposes for which wheat is used.^ (2) It is com- 
paratively easy to obtain varieties suitable for mild conditions, as 
those which are resistant to climatic extremes are more easily grown 
in a milder climate than the reverse. It was therefore decided to test 
the varieties during the following years in the Great Plains. Accord- 
ingly, in 1896 the field experiments were carried on at Salina, Kans., 
and in 1897 at Manhattan, Kans. At Salina Mr. B. B. Stimmel kindly 
donated the use of about two acres of land for the experiments. At 
Manhattan, by courtesy of the board of regents of the Kansas Agri- 
cultural College, the farm department of the experiment station was 
authorized to cooperate with this Department in the experiments con- 
ducted at that place, by furnishing land and other facilities for the 
work. 

During the years of the experiments in Kansas the seasons were 
unusually severe even for that region. As a result it was found desir- 
able to discard a large number of sorts from year to year. Only about 
300 varieties were grown at Manhattan in 1897 out of the 1,000 origin- 
ally obtained, and of these, less than 200 were selected as being worthy 
of continued trial. Over 100 of the varieties finally remaining have 
been made the basis of a large part of the series of field experiments 
now in progress at Halstead, Kans., while a number of the same vari- 
eties are still being tested at the Nebraska Experiment Station Farm, 
Lincoln, Nebr., and at the Arkansas Valley Experiment Station, 
Rockyford, Colo. Through this process of rigid elimination, which is 
a good example of the practical application of the law of the " .survival 
of the fittest" in agriculture, about 100 varieties have been determined 
upon as being fairly representative sorts of the world as regards hardi- 
ness and quality of gluten content. There are many varieties, how- 
ever, which can not be classed with these hardy, glutinous sorts, ))ut 
which, nevertheless, because of their early maturity or particular 
adaptation in other respects to certain localities where hardiness is 
not necessary, and where these sorts would fail because of the lack of 
other qualities, must be considered as equally important. Palouse 

^ For the present, for the want of space, a full discussion of this proposition in 
detail can not be given, although the experimental proof concerning the qualities of 
varieties originating in regions of different climatic conditions will be brought out in 
connection with the table presented in the following pages. The whole matter is 
one of much interest and may be discussed in detail in another publication, The 
Relations of Soi) and Climate to Wheat Production. 



43 

Blue Stem, Australian, Little Club, Early May, AUora Spring-, Yemide, 
King's Jul)ilee, Early Genesee Giant, etc., are examples of this class. 
Adding still to these a number of other sorts, belonging to the Spelt, 
Emmer, and Einkorn groups, which are also hardy, but are especially 
valuable for certain qualities they may furnish in the work of hybrid- 
ization, and then still a few others, mentioned favorably by other 
experimenters, we have in all 2-45 wheats which may be regarded as 
leading varieties of the world. 

For comparative study the principal qualities of these 245 varieties 
are briefly stated in the following table, which is based mainly upon 
investigations of this Department, but to some extent also upon the 
work of others. As regards the field work, it represents a summary 
of the combined results of the three years' experiments, so that each 
column shows as nearly as can be given an average of that quality for 
each variety for the three years. ^ 

The table is made up of twenty-five columns, and the information 
given in each is in most cases clearly explained by the heading, but in 
a few cases a little further explanation is perhaps needed. In column 
2, the following abbreviations are used: C. for common or bread wheat; 
CI. for club; D. for durum; P. for poulard; Pol. for Polish; S. for 
spelt; Em. for emuier; and Ein. for einkorn. In column 8, "stand" 
refers to the degree of completeness with which the plants fill the drill 
row, and of course often measures, though not always, the stooling 
quality of the variety. In column 9, under "spring condition," 
each number expresses in a scale of 1 to 100 the general condition of 
the variety in all respects about May 1. The figures in column 10 
are percentages showing the comparative amount of leaf rust on the 
plant at the date when this rust was most abundant. This column 
is in the main a reproduction of the column of averages in Bui. No. 
16 of this Division, Cereal Rusts of the United States, pages 26-32, 
table 3. Of course the smallest number represents the greatest degree 
of rust resistance. In column 11, the abbreviations C. and D. indi- 
cate that the variety corresponding is resistant to cold or drought 
and the figure shows on a scale of 1-5 how great is the degree of 
hardiness, 5 meaning extremely hardy. In column 19, the word " vit- 
reous" refers to grain which is not oidy very hard but is somewhat 
transpariMit and presents a glassy surface in fracture. Wheats so 
characterized are usually durums. In column 25 is shown the partic- 
ular wheat district of the United States to which the variety is best 
adapted. The districts are indicated by roman numerals having the 
following signiHcations: I, Soft Wheat district; TI, Semi-Hard Winter 
Wheat district; III, Southern Wheat district; IV, Hard Spring Wheat 
district; V, Hard Wint(u- Wheat district; VI, Durum Wheat district- 
VII, Irrigated Wheat district, and VIII, White Wheat district. 



'There is one exception. In column 9, "spring condition," tlie data given refer 
only to the e\iieriinents of 1894-95 in Marvlaiid. 



44 



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June 24 

Do. 
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June 23 


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June 8 


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59 

In comparing- the value of different Aarieties it is very desirable to 
knoAV both the absolute weig-ht and specific gravity of the grain, as 
these phj^sical qualities bear some relation to the chemical composition 
of the grain and to the nature of the plant in general. All the infor- 
mation concerning specific gravity, as well as a number of determina- 
tions of absolute weight given in the table, are the results of a series of 
interesting investigations made in the Seed Laboratory of the Division 
of Botany of this Department by the late Mr. J. C. Dabney, then a mem- 
ber of that Division. Almost all the data of the table concerning nitro- 
gen content of the grain are the result of chemical analyses made under 
the direction of Dr. H. W. Wiley, chief of the Division of Chemistry. 
The greater part of these analyses were made at the request of the 
chief of this Division with samples furnished b}^ the Division. The 
remainder, together with a number of determinations of absolute 
weight, are taken from reports of work formerly done by the Division 
of Chemistry.^ A few anal3"ses are also given on the authority of 
F. B. Guthrie' and Emerich Pekar.^ 

As the value of the grain for making bread and macaroni is meas- 
ured almost wholly by its quality and quantity of gluten content, only 
the percentage of moist and diy gluten and the total per cent of 
albuminoids are given. 

Jt will be noted that no column for yields is given in the table. For 
this omission, which under other circumstances would be a serious 
one, there are three good reasons: (1) In experiments of this kind each 
variety is given so small a space (an average space of one drill row 35 
feet long) that it is not practicable to obtain accurate estimates of 
yield. (2) Many of the varieties tested are already well-known Ameri- 
can wheats, whose yields have often been reported by various experi- 
ment stations, while as to the foreign sorts it is most important, first 
of all, to know Avhether they will prove to be suited to our conditions 
at all or not, before we an^, ready to test their yielding capacity. (3) 
The 3'ield of a variety, whih^ it is of course directly the biggest thing 
to the practical man, is, after all, not a distinct constant qualit^Mii itself, 
but is the combined result of a luimber of qualities acting indirectly, 
and often not thought of at all. For example, such sorts as Clawson 
and Pool(> are fairlv ji'ood wheats, and under mild conditions would 
probably yield better than Turkey; but in west Kansas or. southern 

'See "Analyses of Cureals collected at the World'w Colnmbiaii Kx|)osition," Bnl. 
No. 4o, Div. CheiH., T^ S. Dept. Agric, pp. 39-5.'5, 1895. 

'^ "Noten oil the inilling qualities of different varieties of wheat," Dept. Agric. N. 
H. W., misc. jml). No. 189, p. 47, 1898; "Milling Jiotes on the Lainl)rigg liarvest of 
1897-98," Agric. (laz. N. S. W., Vol. X, Pt. 9, pp. 90()-9iri, Sept., 1S99, and "Absorp- 
tion of water by the gluten of different wheats," Dept. Agrir. X. S. W., misc. pub. 
No. 104, p. 7, 1S9<>. 

^"AVei/.cii mid :\h'hl nnsercr Krde," ini Auftragedes Kig. Ing. .Ministeriunis fur 
Ackerbaiiiiidustric luid Handel, pji. 277, lUniapest, 1882. 



60 

Nebraska they would fail entirely in certain seasons because of drought 
or cold, while Turkey, being very hardy, would produce a much larger 
yield on an average than either of the former, though its absolute 
yield in a good season might not be so great. So, also, it is found in 
the Palouse country that there are certain varieties which have absolute 
yields in that region greater than those of the Little Club or Palouse 
Blue Stem, but thej^ shatter so badly that the net yield of the latter is 
greater. 

As regards the field trial experiments upon which is based the 
larger part of the results given in the table, it must be said that many 
of those sorts whose behavior indicated that they would not be well 
adapted for our use should be further tested before adverse judgment 
is pronounced upon them, especially so if their qualities in other 
respects are good. Nevertheless, the table as a whole shows pretty 
accurateh' which are the best varieties for different districts of the 
country. 

Nothing can be more interesting than the constant observation from 
year to year of the efforts being made by varieties from every country 
in the world, struggling with new" conditions of soil and climate, to 
obtain a footing in a strange land. The gradual elimination of the 
less-adapted sorts by the severity of winter, drought, etc. , soon shows 
unmistakably which are the varieties that will be most valuable. Of 
course it may truthfully be objected that mere hardiness is not of value 
by itself if other qualities are not also present. But, on the other hand, 
it is a further matter of interest how different qualities are often so 
closely associated in the same varieties that if a variety is adapted to 
a certain district with respect to one quality, it is apt to be so with 
respect to at least one or two other equally valuable qualities, though, 
of course, there are serious exceptions. It is also quite worth 3' of note 
that some apparently insignificant characteristics bear an important 
relation to the presence of qualities of direct economic importance. 
As an example of these we may note especially the characteristics of 
the young plant in its autumn stages in connection with the presence 
of certain economic qualities. Hardy winter varieties are rather slow 
starting in the fall, but produce good roots and soon spread out flat on 
the ground in preparation for the cold and snow of winter. The leaves 
are narrow and usually dark green or purplish at first, especially 
near the roots. Spring varieties and most durums and poulards, as 
well as some of the weaker winter sorts, on the other hand, germinate 
quickh' and make a large growth in the autumn, but are cut short or 
entirely killed b}^ the severity of the winter. They produce coarse, 
light-green leaves, but poor roots. In regions of mild winters durum 
and poulard wheats make excellent pasturage because of their rapid 
autumn growth. There is really very little, if any. check to the growth 
from seeding till harvest in localities well adapted for these varieties. 



61 

One well acquainted with wheat varieties i.s usually able to determine 
largely their general classification simply from their appearance in the 
autumn. 

It will be seen also by a stud}^ of the table that there is a very close 
constant relation between hardiness, color, size, weight, and hardness 
of grain, and chemical composition in varieties of the common group. 
Varieties very resistant to cold and drought have small, hard, red 
grains, possessing a large proportion of albuminoids and a relatively 
high specitic gravity, though the absolute weight is likely to be low. 
It is also a general rule that bearded varieties are less susceptible to 
leaf rust, l)ut there are a number of important exceptions to this rule. 
Varieties with harsh, hairy, or glaucous leaves are also usually rather 
resistant to this rust. Varieties early in ripening are often dwarfed, 
and come from warm regions nearly always. Hard-grained winter 
varieties are bearded, as a rule. Drought resistant sorts, whether 
bald or bearded, white or red-grained, possess a larger proportion of 
nitrogen than those which succumb to drought. 

The effect of a change of environment upon the wheat plant has 
already been referred to. That marked changes are effected in this 
way is proved, with respect to chemical composition, by the facts 
given in the table. In a number of instances duplicate analyses are 
given of samples of the same variety obtained from different localities. 
Almost invariably the samples from hot and more or less arid dis- 
tricts show a larger per cent of gluten content. In some instances the 
difference is considerable. Alsace wheat from Ekaterinoslav (Russia) 
furnishes 13.. 58 per cent of dry gluten, while the same variety from 
Poltava, farther northwest in a moister region, shows only 9.30 per cent. 
Improved Fife, though a much liked variety in Australia, produces 
but 11.20 per cent of gluten there in comparison with 16.16 per cent 
in Colorado. Kubanka from Kursk (Russia) possesses 37.79 per 
cent moist gluten and 13.63 per cent of dry gluten, while as grown in 
Germany it furnishes only 20.93 per cent of moist gluten and 8.50 per 
cent of dry gluten. At the same time a sample from the Caucasus 
shows 41.65 per cent of moist gluten. A remarkable difference is 
shown in the ease of Scotch Fife from Nel)raska and Oregon. The 
former sample contained 14.65 per cent of dry gluten, while the latter 
contained onh^ 5.13 per cent, slightly over one-third as much. There 
is a striking example in the case of Palouse Blue Stem of a differ- 
ence in gluten content between two samples from the same Stiite, 
Washington. These samples, however, were no doubt from diffiMcnt 
localities, and no two regions are likely to be much more different from 
each other than are western Washington and the Palouse country of 
eastern Washington. 

A most interesting example of correspondence between climate and 
chemical composition of the grain is exhibited in the case of samples 



62 

from Kursk. As will ))e seen in the table, all samples from this 
locality not only show a very large per cent of gluten, >)ut also a per 
cent always far above that of other samples of the same varieties from 
other localities. The Kursk samples are uniformly so superior in 
this respect that one naturally looks about for an explanation. The 
matter is no doul)t to be explained in this way: It is a fact already 
discussed by the writer in another i)ublication' of this Department 
and referred to before in this })ulletin that the nitroo-en content of the 
gi'am is greatest in regions having black soils, extremes of temperature, 
and very low rainfall. In Russia extreme heat and aridity increase 
eastward and southward as a rule. The government of Kursk, how- 
ever, presents a remarkable exception to this rule, especialh' as regards 
rainfall. The normal yearly rainfall is 16.9 inches, while in Woronetz, 
Tambov, and Ekaterinoslav, east and south of it, the normal is 21 and 
22 inches. It is apparently situated in an arid area, with greater rain- 
fall all around it. At the same time the extremes of temperature are 
great and the soil is of the best in the ''Chernozem"" (black earth) 
region. 

As before stated, all the experiments and ()l)servations which form 
the basis of this table have been made with the view of obtaining some 
reliable foundation for future wheat improvement. The general con- 
clusions of immediate value to the wheat growers that are to be drawn 
from this work of the Department, and which are of rather wide 
application, maj' be stated as follows: 

(1) Considering all qualities, the best wheats in the world are of 
Russian origin, coming particularly from eastern and southern Russia. 
They are resistant to cold and drought, are more or less resistant to 
leaf rust, and have the best (pialit}- of grain. They are fairly earh^ 
in ripening and are good fielders. Under the head of remarks the 
jnelds per acre of several newly introduced Russian sorts in Kansas 
and Colorado are given in the table. For varieties not yet acclimated 
it will l)e seen that these 3nelds are very good. The yields and weights 
per bushel in Colorado are furnished bj' W. F. Crawle}^, superintendent 
of the Arkansas Valley Experiment Station at Rocky ford in 1897. 
The following may be considered as the best Russian varieties so far 
known: Arnautka, Kul)anka. Kubanka Red Winter, Crimean. Sando- 
mir. ITka. Chernokoloska. Buivola, Red Winter, Bearded Winter, Yx, 
Odessa, Sarui-bug-dai, Ghirka Spring, Ghirka Winter. Russian, Belo- 
turka. Mennonite, and Turkey. (See Plate VIII, Fig. 1.) 

(2) The earliest ripening wheats are often dwarfed and come princi- 
pally from India, Australia, and Japan, though a few are from the 
^Mediterranean region. They are usually soft white wheats, but those 
from Japan are red, rather hardy, and possess a fair gluten content. 



' Russian cereals adapted for cultivation in the United States, Bui. No. 23, Div. 
Bot., pp. 8-11. 



Bui 24, Div, Veg. Phys. & PaTh . U. S. Dept. of Agriculture. 



Plate VIII 




Fig. 1.— Group of Russian Wheats in Experimental Plats at Garrett Park, Md. 

(Original. < 




Fig. 2.— Experimental Wheat Plats at Garrett Park, Md., showing earliness of 
KING'S Jubilee; 1 , Leaks ; 2, King's Jubilee; 3, Tuscan ; 4, Purple. (Original.! 



63 

The ])ost varieties so fur known for our use from these regions are: 
Early Japanese, Yemide, Kintaina, Japanese No. 2, Onigara, Daruma, 
Japanese No. 1, Japanese No. 4, Shiro-yemidashi. AUora Spring, Stein- 
vvedel Early Baart, King's Jubilee (Plate VIll, Fig. 2), Roseworthy, 
Canning Downs, Kathia, and Nashi. 

(3) Though varieties of Russian origin are, on the whole, the best, 
there are certain sorts from other eounti'ies which behave much like 
them. These are P\ilcaster. Lancaster, Tasmanian Red, Fultz, Chu- 
but, Frolifero, Rieti, Nashi, Mediterranean, Tangarotto, and Valley. 

(4) Durum, Polish, and poulard wheats, besides being admirably 
adapted for making macaroni, are all rather resistant to leaf rust. 
The best known varieties are: Arnautka, Kubanka, Beloturka, Medeah, 
El Safra, Galland's Hybrid, Petanielle noire de Nice, Chernokoloska, 
Sarui-bug-dai, Volo, Missogen, Atalanti, Cretan, Wild Goose, Polish, 
and Nicaragua. 

(5) Common bread wheats can not be depended upon to resist rust, 
but the best in this regard are: Turkev, Crimean, Prino-le\s Defiance, 
Rieti, Oregon Club. Fulraster, Odessa, Pringle's No. 5, Mennonite, 
Velvet Blue Stem, Saskatchewan Fife, Mediterranean, Alsace, Nashi, 
Ghirka Sj^ring, Frolifero. Bellevue Talavera, Ghirka Winter, Red 
Winter, Bearded Winter, Theiss, Deitz Longberry, Arnold's Hybrid, 
Sonora, and Banat. 

(()) Einkorn resists leaf rust completel}^, and emmers resists it to a 
high degree at least. 

(7) The very hardiest winter varieties are Turkey, Crimean, Red 
Winter, Ghirka Winter, Yx, and Bearded Winter. During the unusu- 
ally severe winter at Manhattan, Kans., in 1896-97, these varieties 
fared very well when nearly all the experimental varieties of the regu- 
lar experiment station plats at that place winterkilled, though well 
acclimated. 

(8) Club wheats ai'e usually soft grained and tender sorts and 
adapted oidy to mild climates, like that of California. They are excel- 
lent yielders. Among the best of them are: Little Club, California 
Club, Palouse Red Chaff, Sicilian Red S(juare-head, Herissoa barbu, 
Herisson sans barbes, and Chili Club. 

WHEAT BREEDING. 

If we wish to continue our improvements in wheat culture, it is evi- 
dent that we nuist soon depend upon other means than simply the 
introduction of vai'ieties new to the country. During the earlier his- 
tory of the country it was a (juestion even whether wheat could be 
grown at all in many of the new regions open to settlement, and prac- 
tically every variety had to be tested. Their introduction, therefore, 
naturally played the greater part in wheat impro\'ement, and has 
continued to do so, in less measure of course, almost to the present 



64 

time. But the time will soon arrive when there will be no further 
varieties to introduce better than we already have. The work now 
being done by the Section of Seed and Plant Introduction of the Divi- 
sion of Botany of this Department is especially hastening- the approach 
of this period. So far as our knowledge goes at present, there are 
now but two regions in the world which produce varieties likely to be of 
particular value to this country from which we have not already secured 
seed for trial in considerable amounts. These regions are (1) the north- 
ern portions of India and China, including Tibet, and (2) Abyssinia. 
There ai"e still some of the very best varieties to be obtained, however, 
from regions alread}" drawn upon, such as southeast Russia, Turkestan, 
and Japan. No more important work could be done at present than 
that of securing all these new sorts from different regions, for of 
course it is a great waste of^ time and labor to the wheat breeder to 
spend years in the production of varieties having special qualities if 
other sorts alread}^ possessing these qualities can be readily obtained 
from other countries. 

But, as stated at the beginning of this report, although many valu- 
able improvements have resulted and are likely still to result from 
introduction, there are often certain combinations of qualities found 
to be extremely desirable for a particular region which, so far as we 
yet know, do not exist in an}" one variety, native or introduced. Such 
ideal sorts are therefore to be acquired by improvements of the vari- 
eties now in use, which must be accomplished through hybridization 
and selection. Besides, in certain varieties ideal in other respects, such 
qualities as rust resistance, yielding capacity, etc., may exist already, 
but not to a sufficient degree. In such cases these qualities must be 
increased by selection of seed from individuals which exhibit them to 
the greatest degree. But manifestl}" the greater number of varieties 
one has at hand, either native or introduced, especially if these have 
been chosen with great care, the greater are the number of chances 
offered him for selecting and improving these qualities. The trial of 
introduced sorts, therefore, in comparison with native ones simply 
gives one a practical knowledge of the facts herein discussed under 
the heading '"Sources for desirable qualities." With these facts in 
mind, together with those concerning characteristics and needs of the 
different wheat districts, one is prepared for effective work in wheat 
improvement. 

IMPROVEMENT BY SELECTION. 

During the last thirty or forty j'ears considerable work has been 
done in wheat breeding through selection, though it is only a begin- 
ning in comparison with the great amount that ma}' be done. It may 
be of interest to note a few of the most important instances of the 
actual production of new sorts in this wa}'. 



65 

In 1862, in Mifflin County, Pa. , Abraham Fultz, while passino- through 
a field of Lancaster wheat, which i.s a bearded variety, found three 
heads of bald wheat. He sowed the seed from these heads the same 
year, and continued sowing a larger amount each year, until he ol)tained 
sufficient seed to distribute it pretty well over the country. It soon 
became a well-marked and popular variety, called Fultz from the name 
of the breeder, and is now the best known of American wheats. In 
1871 this Department distributed 200 bushels of the wheat for seed. 
This variety is rather early in ripening, fairl}^ hardy, and possesses a 
semihard, red grain of good quality. It comes nearest being a general 
purpose wheat of all our varieties, being grown with good success in 
nearly all parts of the country and in several foreign countries. 

Next to Fultz, one of the best known of our native wheats is White 
Clawson, or >;imply Clawson. This variet}^ originated in Seneca County, 
N. Y., in 1865, through the selection of certain superior heads from a 
field of Fultz by Garrett Clawson. On planting the grain from these 
heads, both a white and red-grained sort resulted the following season. 
The white wheat was considered the best, and the pint of seed obtained 
of this sort was sown, producing 3!J pounds the following season. The 
third year after this 254 bushels were harvested, and that season the 
variety was distributed to other farmers. In 1871 this variety took first 
premium at the Seneca County fair, and in 1874 seed was distributed 
by this Department. Though judged inferior by millers at times, this 
variety has become a very popular one. It must not be confused with 
Earl}^ Red Clawson, a very distinct variety. It is a bald wheat, rather 
hardy, with soft, white, or light amber grains. Early Red Clawson, 
because of its earliness, has taken the place of this variet}^ to a great 
extent in recent years. 

One of the best of the more recently produced varieties is the Rudy, 
which was originated at Troy, Ohio, in 1871, b}' M. Rudy, through a 
careful propagation of the seed from a superior and distinct stool of 
wheat found in a large field. It is a semihard or soft reddish-grained 
wheat, bearded and with white chatf. It is widely grown in Ohio, 
Indiana, and adjoining States. 

A number of tiie different varieties of Fife and Velvet Blue Stem of 
the spring- wheat States were also produced by simple selection. 
Wellman's Fife is a good example. In 1878 D. L. Wellman, of Frazee 
City, Minn., received a sample package of Scotch Fife wheat from the 
Saskatchewan Valle}', in Manitoba. This was sown in the sprmgof the 
following year, and as a result it was found that the seed was badly 
mixed. Removing all plants but those of the true Fife and propagating 
carefully from year to year, Mr. Wellman gradually bred upward a ver}^ 
pure strain of the Fife, which became known as the Saskatchewan Fife. 
From the crop of 1881 were seliM-ted some uinisually large heads, and 
from the seed of these as a beginning he finally produced a rather 
4879— No. 24 5 



66 

distinct sort, now known as Wellman's Fife. In a similar manner 
Powers's Fif e, Hayne's Blue Stem, Bolton\sBlue Stem, and other sorts 
have been produced b}' the men whose names they bear. 

By the process of selection an unusually good variety of white wheat 
for the Eastern States, usually called Gold Coin, has very recently been 
produced by Ira W. Green at Avon, N. Y. Several years ago he 
grew a field of Diehl Mediterranean, a bearded, red-grained wheat, 
and while passing through this field one day found a bald head possess- 
ing white grains. Planting every grain of this head, he found as a 
result next season that he had heads with very long beards, some with 
short beards, and others with none at all. The grain also was mixed, 
some red and some white. He desired a bald wheat, since the beards 
interfered with his success in woolgrowing, hence only the grains 
from the bald heads were again planted. From this as a beginning, a 
practically new variety resulted, which he called '"No. 6." It has 
proved to be of considerable value for certain localities, and is already 
pretty well known. Various names have been given to it by difierent 
seedsmen, but it is best known by the name Gold Coin. 

In instances like those just related the change has been so great as 
to produce really a new variety. But, of course, the majority of 
improvements made by selection do not represent such marked changes, 
though there is a great tendency among breeders to establish new 
varieties on the basis of very slight improvements. In a majority of 
the instances above described the circumstances too are such that one 
can not escape the thought that the abnormal heads found in the fields 
were the result of natural crosses. In fact in the cases of Clawson 
and Gold Coin wheats this is almost certain, since the seed from the 
first heads continued to produce sporting progeny, the following year. 
Or it is possible in the case of Gold Coin that the sporting was simply 
a later cropping out of this phenomena in the Diehl Mediterranean, 
which is itself a hybrid. Besides these cases, there are also instances 
mentioned by other writers which pretty well establish the fact of the 
occurrence of natural crosses among wheat varieties,^ though, of 
course, such occurrences are rather rare. On the other hand, in the 
work of hybridization the selection of parent forms and the after 
.selection of the best individuals from the sporting ofispring are by far 
the most critical operations to be performed. Hence selection is both 
the most important part of all the work of wheat breeding, and is also 
to be considered from two rather difierent standpoints: (1) that of its 
operations in connection with hybridization (natural or artificial), and 
(2) in making the ordinary less striking improvements in the same 

»See especially Rimpau's statements in his article on " Kreuzungsprodukte land- 
wirthschaftlicher Kulturpflanzen," in Landwirthschaftliche Jahrbiicher, Bd. xx, S. 
347-350, 1891. 



67 

variet}'. The former phase will be best discussed under the subject of 
h^'bridization. 

In eases like those of the different varieties of Fife and Velvet Blue 
Stem, such as Wellman's Fife, Haj^ne's Blue Stem, etc., above men- 
tioned, as well as many others that might be described, the new sort, 
if it is rightly called such, has been produced b}^ ver}^ gradual improve- 
ments during many years. It is not a selection of varieties, nor of 
offspring showing combinations of elements from different varieties as 
a result of crossing, but is simply a selection of individuals. The 
process is slower and the changes effected are not so great at an}^ one 
time, but in the end important results ma}^ be reached. 

Selection of this kind is, of course, the most common, and occurs 
constantl}' in nature, especiall}^ in connection with the qualities of rust 
resistance, hardiness against cold, etc. Farmers prett}^ generally 
practice a sort of selection of seed corn, and often too of potatoes, for 
seed. Comparatively little attention, however, is paid to the selec- 
tion of Av heat for seed, although the wheat plant is ver}" susceptible to 
its environment, furnishing therefore many variations as a basis for 
excellent results in this line. 

It is through this kind of w^ork, but carried on thoroughly and svs- 
tematically, that Prof. W. M. Hays, of the Minnesota Experiment 
Station, has attained some ver}^ interesting and practical results with 
the Fife and Velvet Blue Stem varieties of that region. He has prac- 
ticed rigid selection with these varieties for a number of 3'ears, giving 
special attention to yield and quality of grain as shown by the baker's 
test. Certain new strains capable of giving to the farmer substantial 
gains over others have already been produced in this wa}'. He has 
also developed a method of keeping records which is worthy of the 
attention of other experimenters. 

In the preceding pages the special needs of different wheat districts 
have been discussed, and also the groups of wheats from w^hich, in 
crossbreeding, the qualities for satisfying these needs may be secured. 
One must not forget, however, how much such qualities may ))e 
increased in the varieties already grown in the district, and should 
remember too, that even after great improvements have been secured 
through hybridization, very careful selection must be practiced in 
order to maintain the standard of excellence reached, especially if the 
variety is to be grow^n under conditions adverse to the production of 
the particular qualit}' accjuired. 

Some of the most important qualities of the wheat plant that may 
readily be increased on any farm simply by selecting seed from those 
plants which exhibit these qualities to the greatest degree, are yield, 
drought resistance, winter hardiness, rust resistance, earliness in rip- 
ening, quality of the grain in any respect, and nonshattering. If in 
passing through a field certain i)lants jire noticed which are almost or 



('.8 

(juitc I'rrc From rust, \vhil<*- thc.othors aro (;()nsi(l(M"iil)lv rust(Hl, nud tlio 
lociility should 1i!1|)))(mi to l)(^ one in whicli rust is usually vory hud, 
such heads should hy all means he sclecti'd, sown separately, and from 
th(^ ))roj^-eny the most resistant individuals a<4ain selected. It imist of 
(U)urse he noted thai </// .sdectlov-s for' sred xJiovld he inade in the field. 
Kven sele<;ti()iis lor oi'eat(U' yield or for size oi- (juality of grain can 
not he pi'operly mad(^ fi-om the harvested gi-ain. It is fortunate that 
often two or more (pialities may he improved hy scdecting the same 
individuals. Voy example, individuids that arc^ very winter hardy arc 
also lik(>-ly to he I'ust i-esistaid. in miiiiy instances. Great yieldi no- 
power and nonshattei'ino- ni:iy idso occui' in the same individual, while 
gluten content iind drought resistance may (^xist together in ceitain 
othei's. 

Ill Mil ai'ticie \)\ the writer on " Impi"o\cmeiits in wheat culture" ' a 
simple metluxl is suggest(Ml which, if practiced, would enable any 
farmer to constantly and cIlectiNcly im])ro\-e th(^ yield and (piality of 
grain with little lioiihle. hut with grejit profit in the <^w\. As this 
iiK^thod niiiy he employed e(|ually well tor the improvement of any 
othei- (piality of the plant, tiid'e is jjiohahly no mor(^ fitting way of 
closing the discussion of this topi<- than to I'cproduce here the desci'ip- 
tion ot" that method with such modilications as are necessary to make- 
it api)licahle for any improv«>ni(Mit desired. It is as follows: 

Hegin pr:icli<'ing the constant us(> of a wheat-hreeding ])lat of 1 acre 
or more from which to select sccmI each year. Locate this plat at ditter- 
i'nt paits of the farm every two or three years, preferably in alterna- 
tion with cloN'ei' or other leguminous ci'ops, and gix'e it the best of care, 
flust hefore liar\'est go through a tield of a good, hardy, standai'd variety 
that has gi\'en the best results in the locality, and mark ])lants that 
exhihit to the higlu\st degree the special (luality which it is desired 
to incn^ase, su<h as freedom from rust, fertility of head, or ()therwis(>, 
and which are at. the same time at least as good as the ax'cragii in other 
respects. At harvest tim<> cut with a sickle enough of these marked 
j)lants for sowing the plat and, after thrashing them, select the largest 
and most \igorous seed foi' this pur])os(\ by means of a scr(MMi or even 
hy hand picking. Sow the plat early, drilling it at theavei'age rate of 
ai)out \.\ bushels ]M>r acre. Next s(»ason use none of the Held crop for 
seed, but select in the same mannei' enough of the l)(>st plants from 
this brecMling ])lat for r«>seeding the plat and use all the remainder for 
sowing the general cioj). In the following season and eai'h succeeding 
season practice exactly the same method. In this way seed is never 
taken from the g<MU'ral crop, which can not he given the same care as 
the smtdl plat, and there is a constant selection of set'd which is more 
and more rigid e\'t'ry year. Moreover, tlu>re is no extra lahoi" involved 
exc(^pt the small amount iHMpured for seed selection each year. Of 
cours(> the hreediiig plat should he k(>pt constantly free from rye or 
other foreign heads and weeds. 

' YciirlxKiU I'nittMl Stiilcs i)cii;iil mciit <>l' Au'ricultiirc, ISiXl, ])a^es 489-498; also 
ivpiiiito'i. 



IINU'UON KMKN r IH 1 1 V UKl I H/A'l'K )N. 

Ill inanv iiistjuu-os (luiilitics tliiit arc xcry (l('siral)lo or vyvu lu'ccssarv 
for a partifuliir districl aic ciitircly lackinu'. or at least not ])ivs('iit in 
any a])pr('cial)l(' dcurcc. in Niirictics which arc in all other respects 
adinirahly adapted to the district, in such instances th(> iinproN eincnt 
of the vaiMety must be accomplished hy l>r(M>din>i- into it the desired 
quality from som(> other sort ]M)ssessiny- it to m hiu'li deorcc. Thoiinh 
not so simi)lc a process as that just descrihed. and Irauolit with iinich 
more uncertainty in its operations, hyhridi/ation is 5)rten absolutely 
necessary for ])ro(lucinj>- radical chanycsoi' oi-cat moment, or, in ciisesof 
emerj^ency, for satisfyin«i' an inipeiati\-e need, wIumi the ordinary i)roc- 
ess of s(dection alone would either he too slow or f:iil entirely. 'The 
possi))ilities for im])rovement through hyhridi/ation, accomi)anied l»y 
discriminating- sidection, in the hands of skillful hnMulers, s(>em to he 
practically unlimited, especially in the <-asc of a [Anui so closely s(>lf- 
fertilized as wheat. Nevertheless, comi)aratively little work of this 
kind has vet been done with the cereals, and particularly so in this 
country. Also the j^reater part of what has Ix-eii accomplished, thoiiuh 
productive of important residts, has been of rather an elementary 
natui'e. 

It may l)e advisable^ before continuino- the discussion to ^ive lirst 
a l)rief account of some of the principal wlu'at hybrids produced in 
this country. Nearly all of these new sorts have i)roved to be of 
more or less value in wheat improxcment, while a few of them have 
become well-known factors in dev(dopin<;- the industry. 'VUo pioneer 
in the production of wheat hybrids in this country is ('. (i. Pi-in<ile of 
Charlotte, Vt. Sotne of the most im])ortant of his hybiids are Crin- 
gle's No. 4, No. 5, and No. <), Pi'inolc's Best, and rrin<;l(^'s Deliance. 
The last-named vari(^ty was produced in Vermont in 1S77. In ISTS 
it was inti'oduced into soutluu'ii C!alifornia, and has e\'er since been 
a standard soi-t there, ])articulai-ly on account of its lust resistance. 
In the lield experiments conducted by this Department this variety 
and rrinole's No. 5 have always proved to be rather hardy, lust resist- 
ant, and productive. 

I'rof. \. K. Hlount, while connected with the Colorado Aorjcultui-al 
College, did much work in crossing wheats, and lunong a comparatively 
large numbei' of hybi'ids prodiacd some that are now not Only W(dl 
known ill this counti'y, but ai'c among the most valuable soils in 
.Austialiii. They are used by Australian wheat breeders [)robably more 
often than any othei- foi'eign sorts us the jjarents of hybrids pnxhn'cd 
in that country. The most important of Blount's wdieats are perhaps 
the following: Amethyst, ImproNcil Fife, I loiiil)lende, (Jypsum, 
Blount's No. !<>, Felspar, Ruby, and (Jranite. (Jypsum (Blount's 
Lambrigg), Iloi-nblende. Quartz, and Improved Fib' are the mo.st 



70 

popular in Australia. In New Mexico, where field tests of all his 
hybrids were last made, Ruby and Felspar are now most extensiyely 
grown. Blount's No. 10 is much prized in the northern portion of the 
Pacific coast district, where the yariety Oregon No. 10 is probably 
identical with it. An important characteristic of several of Blount's 
hybrids is that they are rather rust resistant and it is partly for this 
reason that the}' are so much used in Australia. Improved Fife, how- 
ever, has also an excellent quality of grain. 

One of the very best varieties of this country, standing probably next 
to Fultz in popularity, is Fulcaster. It was produced in 1886 by S. M. 
Schindel, of Hagerstown, Md., and is a hybrid between Fultz and 
Lancaster. This variety is a bearded, semihard, red-grained wheat, 
considerably resistant to leaf rust and drought. It is grown pretty 
generally throught the country, but especially in the region from 
Pennsylvania to Oldahoma, including Tennessee and North Carolina 
to the southward. 

Recently Professor Saunders, of Canada, has produced a number of 
new sorts adapted for growing in the Northern States and Canada. 
Perhaps a half dozen of these — such as Preston, Percy, Dawn, Alpha, 
Progress, and Countess — are now pretty well known. 

All the hyl)rids just described have been produced, as a rule, in the 
most simple way; that is, they were the direct result usualh" of crosses 
between varieties comparatively closely allied. That they have met 
with so much success, therefore, is convincing evidence that most 
remarkable results must follow extensive hybridization experiments 
with this cereal when composite methods are employed with parents 
selected from wideh^ different varieties. No experiments completely 
of this nature have been made in this country. 

Composite crossing, however, is practiced by A. N. Jones, of New- 
ark, N. Y., but always with parents comparatively closely allied. He 
has without doubt done the most important work in wheat hybridiza- 
tion in this country. Of all American wheat hj^brids recently pro- 
duced, Jones's varieties are to-day most widely used. In composite 
crossing, after one or more regular simple crosses have been made, 
one hybrid is either crossed with a fixed variety or with another 
hybrid, and the offspring of this last cross may be again crossed with 
another fixed yariety or hybrid, and so on. In this way the variations 
that are always induced eyen in ordinary simple crosses are of course 
multiplied many fold, giving practically an unlimited chance of select- 
ing from sporting progeny. The results ol^tained from composite 
crossing, therefore, even with varieties closely allied, are not to be 
compared with those from simple crosses. 

Aside from the practice of composite methods, another feature which 
characterises Jones's work is the tendency he has shown to adhere to a 
particular aim in all his operations. The Avheats grown in New York 
and other Eastern States are inclined, on account of the nature of the 



71 



soil and climate, to be soft and starchy. Recognizing that the best 
bread flour is made from varieties containing a large proportion of 
gluten, Jones has given much attention to raising the standard of 
Eastern varieties in this regard, and has in a large measure succeeded. 
Of his tirst varieties the two most popular are his Winter Fife and 
Early Red Clawson. The former is descended! from Fultz, Mediter- 
ranean, and Russian Velvet, and is a bald, velvet chaff wheat with 
amber grains, soft or semihard. It is grown chiefly in the Eastern 
and North Central States, and would be of great value in the Palouse 
country were it not for its shattering. Early Red Clawson is a hyln-id 

Mediterrane an 

Russian Velvet 
Jjancastev 



JTuhrid 

Earh^ White 
Leader 



)WinterFife 
^Troih Straw 




Go Ide n Cro s s, Jn 



Hiibrid 



jITyhrid 
Iron Straw 

arlxf Genesee Giant 

Fii;. 1.— I>i!iKrani shcuving ix'rtigree of Early Genesee Girtiit. 

of Clawson and Golden Cross, the last named being a hybrid of Medi- 
terranean and Chuvson. Though in some respects similar to Clawson, 
it matures earlier and has a stifler straw. It has a reddish grain. It 
is a bald, red-chaflV<l sort, with rather club-shaped, s(iuarely f(n-med 
heads. In the last eight or ten years it has l)ecome very well known 
in the northern winter-wheat States. Probably the next best known 
variety is Early (ienesee Giant, which has been nuu-h grown througii- 
out New York and Pennsylvania. As a good illustration of Jones's 
method of composite crossing, the full pedigree (flg. 1) of this hybrid, 
so far as known to the writer, is here given. 

It will be noted that all its ancestors are varieties belonging to the 
common bread-wheat group. Yet samples of this hybrid show strik- 



72 



ingly in various ways the effects of composite crossing, especially 
exhibiting- great improvement in vigor. 

In the production of Diamond Grit (Plate IX) and Bearded Winter 
Fife, Jones has most nearly approached the wheats of the Plains States 
in gluten content. The former is a direct cross of Jones's Winter Fife 
with Early Genesee Giant, and is a bearded, white-chaffed, semihard, 
red-grained variety. Bearded Winter Fife is descended from the Win- 
ter Fife as one parent, but is hardier and possesses a grain of better 
quality. Another hybrid which shows well the advantages of a good 
ancestry is Early Arcadian (Plate IX). It is a bald, red-chaffed 
variety, with club and square-shaped heads and light amber grain, and 
is a direct cross of Early Genesee Giant with Early Red Clawson. It 
is very productive and of even growth in the field. 

But even the method of composite crossing, productive as it is of 
valuable results, if practiced only with varieties closely allied, as just 
described, leaves still lacking some important sources for obtaining 
more rapidly and surely the improvements desired. For anything like 
perfect attainment of certain qualities it is necessary to practice com- 
posite crossing with varieties of t-ntirely different wheat groups^ a prac- 
tice which, so far as known to the writer, has only been carried out to 
any great extent by John Garton, of Newton-le-Willows, England, and 
William Farrer, of New South Wales. In all the experiments in this 
country at most but two wheat groups have been drawn from, the 
common and club wheat groups. But by combining the composite 
method with the selection of varieties from widely different groups not 
only are the number of variations induced again multiplied many fold 
over those induced by the composite method in the same group, but 
the deo-ree of variation also is much increased. Certain qualities may 
be obtained in this way that would otherwise even probably not be 
secured at all. For example, to secure the quality of nonshattering 
completely it will probably be imperative to introduce it from the spelt 
or emmer group, while satisfactory resistance to leaf rust must be 
obtained by crossing with the durums. Besides the direct advantages 
of increased and multiplied variations induced through selection of 
parents from different groups for any particular district one is thereby 
able also to produce sorts adapted for other very different districts, 
thus allowing his work to be of much wider usefulness. Thus after 
the production of Jones's Winter Fife, which has been so popular in 
the Eastern and North Central States, the introduction of the spelt ele- 
ment, without loss of other qualities, might have made it of even greater 
value for the Palouse country, where it is very much desired, but can 
not be used because of its shattering. 

The wheat plant being so closely self -fertile, there is within it, lying 
dormant, a wonderful power to vary (a power far greater than in plants 
cross-fertilized in nature), which is thrown into action when different 



BUL. 24, DIV. VEG. PHYS. & PATH., U. S. DEFT. OF AGR. 



PLATE IX. 




0. G. PASSMORE. A.Hotrn A Co. Uni.Rnlllniorc. 

HYBRID WHEATS, EARLY ARCADIAN AND DIAMOND GRIT, BY SIDE OF PARENT VARIETIES. 

1, Early Red Clawson (la, grains); 2, Early Arcadian (2o, qrains); 3, Early Genesee Giant (3ff. grains); 

4, Jones'8 Winter Fife (4a, grains); 5, Diamond Grit (5a, grains.) 



73 

varieties are artifically crossed. But the enormous amount of varia- 
tion induced by composite crossing between diiierent wheat groups, 
though it must be apparent to anyone, can only be appreciated by 
seeing the results in the field. The writer had the opportunity of 
observing such results in the experimental plats of the Garton Broth- 
ers, in Lincolnshire, England. Their experiments in this line are by 
far the best illustration of this kind of work in the world. In certain 
plats were shown the offspring of the second generation from the last 
cross in cases of series of crosses in which parents were taken from 
four or even five different wheat groups. In these plats of the second 
year the progeny had reached the highest degree of variation, and the 
number of very different forms shown, which came directly, of course, 
from two parents, were astonishing. There were forms, apparently, 
of true durums, poulards, spelts, Polish, clubs, and intergradations 
between these groups, and in many cases characters of every group 
were easily observable in the same plant. There were large, small, 
short, longj. bearded, and bald heads; velvet and smooth leaves; broad 
leaves, narrow leaves; leaves glaucous and not glaucous; and plants 
rusted and not rusted, and of all heights. (Plate X.) 

Some of the practical results attained by the Gartons, which are 
of the greatest economic importance and which serve to show the 
superiority of their method of operations, should be mentioned. 
First, it was desired to combine with the yielding capacity of a local 
variety, rust resistance and tenacity of chaff. By intercrossing this 
variety w^ith a spelt and a durum these requirements were readily 
obtained, as witnessed by the writer. But, in addition, the added 
fertility of the head drawn from the spelt, together, possibly, with 
the increased vigor of the seed which is often the result of hybridiza- 
tion, still further increased the yield of the original variety. These 
qualities could not possibly all have been secured by crossing common 
varieties only, since no varieties of the common group are known to 
be satisfactorily rust resistant, and only the spelts, emmers, and ein- 
korns are perfectly tenacious of their chaff". In other hybrids great 
improvement has been made in the hardiness and gluten content of 
grain, size and fertility of the head, etc., while in nearly all cases the 
yio\d has been increased. 

Some examples of the results in crossing oats and barley are also 
very interesting. Common oats have ])een changed into huUess sorts, 
but retaining something near the original size of grain, and at the 
same time one effect of the operations has been to so increase the 
length of the spikelets as to double the usual yield. The wild oat 
{Avena fatua) has been used successfully in many of these experi- 
ments, "'ivino- extra vioor and fertility to the new hybrids. In the 
case of barleys the yield of the .six-rowed sorts has been combined 
with the excellent {quality of grain of the two-rowed Chevalier. This 



74 



combination has been accomplished mainly by forcing fertility in the 
rows of sterile spikelets of the two-rowed variety. Besides the 
experiments with cereals, the Gartons have reached many interesting 
results also with the grasses, beans, and clovers. 

The pedigrees of two of the Gartons' hybrid wheats are here given, 
both in the form of an equation and genealogically for illustration of 
their method, as follows: 

(1) Hybrid= ! [Tala vera X (Hunter's White X Essex Red)] X [Hunga- 
rian Red X (Pedigree A¥hite X Black Spelt)] I X [(Pedigree White X Black 
Spelt) X (Hunter's WHiite X Essex Red)]. (See fig. 2.) 

(2) Hybrid = [(Black Spelt X Hardcastle White) X (Mainstay X Hun- 
garian White)] X ! [Pedigree Red X (Black Spelt X Hardcastle White)] X 
(White ChiddamX Hungarian Red);. (See fig. 3.) 

For many years W^illiam Farrer has been l)usilv engaged in the 
work of improving wheats for Australia, especially with respect to rust 



Fediqree JVJiite 



Hihnte.7'''s JVhite 



SunqartaTi. 



^Jijssexlled 
Tctlcn^era 




ByhridS JSuhridS Miibrid'^ 

^Q Hvhrid 4 

Hiihridd 




Hvhrid 7 

Fig. •.;.— Diagram showing pedigree of one of the Gartons' hybrid wheats. 

resistance, and has not only practiced composite crossing, but has found 
it necessary to use in many cases parent forms from difierent wdieat 
groups, including comjiion wheats, club wheats, durums, and poulards. 
His new^ varieties, although chiefly adapted to Australian conditions, 
are many of them most excellent ones, which show their high breed- 
ing to a marked degree, and represent an enormous amount of work. 
Among the very man}" parent varieties used in his work are the fol- 
lowing j.^xcellent sorts: Improved Fife, Gypsum. Tourmaline, Horn- 
blende, Quartz, Early Japanese. Beloturka. ^ledeah. Sicilian Red 
Square-head, D'Arblay's Hungarian, Ziumierman, Ward's Prolific, 
Fultz, Ward's White, Blount's Fife, several early maturing Indian 
varieties, and others that might be considered just as good as these. 
The following pedigree of one of his hybrids will illustrate his methods: 



Bui. 24, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



Plate X. 



O 

o 

TJ 
O 
W 

H 
m 

O 

c 

CO 
CO 

CD 

< 



> 

X 
H 
O 
Z 
CO 

CO 
I 
O 

S 



CO 
> 



m 

CO 



I 
m 

TJ 
XI 

O 

m 

z 



H 
I 

m 

r 
> 

CO 

H 

O 
3J 

o 

CO 
CO 





75 



Hybrid = ; [(Medeah X Gypsum) X Hornblende] X [Hornblende X 
Ward's White] | X Improved Fife. (See fig-. 4.) 

Medeah is a North African durum wheat. The others are common 
bread wheats. This new hybrid has been tested by the writer in the 
field experiments of this department, and was found to be a vigorous 
sort. 

Among Continental breeders probably the most important work with 
cereals has been done by W. Rimpau, of Schlanstedt, German3\ 
Though not characterized l>y the use of composite methods, Rimpau's 
work shows a number of important examples of the results obtained 
by crossing with parents from different wheat groups. Some of the 
most interesting of the crosses showing various forms similar to the 
parents and intergrading as to form, color, etc., are the following: 
Rivett's Bearded Spelt (poulard) X Red German Bearded. Rivett's 
Bearded X Square-head (club group), and Mainstay X Square-head.^ 



Black 

Spelt 



ffardcastle 
White 

TiTiite 
ChidcLcLm^ 



Hunqarian 



Hungctrian 




^HedL Mainstcm Wrvite 



'Hybrids, 




fijbrid < 



'NubridS 



Huhridj 7 



Fig. 3. — Diagrnin shuwing pudigree of one of the (iartons' hybrid wiipats. 

As already shown in the earlier part of this bulletin, wheat is, of 
all the principal cultivated crops, probably the most intluenced by its 
environment. Connect with this the fact also of its close self-fertiliza- 
tion, and it is readily explained why there are so many different varie- 
ties, each best adapted to its particular district. The same variety 
taken to localities chai-acterized by widely different conditions will 
gradually change to suit the new conditions, thus giving origin to dif- 
ferent strains. At the same time new hybrids, when well Hxed. are 
not likely to be broken up b}' subsequent natural crosses, as in the case 

'For an interesting account of ponio of Riinpau's work, written l)y himself, see 
"Kreuzungsprodukte landwirthschaftlicher Knlturpflanzen." Lanthvirthsehaftliclie 
Jahrbiicher, Ltl. XX, S. o;>5-o71 (lUus.), 1891. 



76 



of some other species. It is important, therefore, that all hybrids 
intended for a particular district should either be produced in that dis- 
trict or transferred there before they have become fixed, in order that 
the careful selection necessary may be continued in accordance with 
the tendencies developed under the influence of the new conditions. 

Ward's White 

^Gypsunh C 

Jiomblenae 



^edeah 



Hybrid 1 




Huhrid 2 



KTjbrid4 



Improved Fife 



SyhridJ 

Fig. 4.— Diagram showing pedigree of one of Farrer's hybrid wheats. 

Another matter of importance should be noted before leaving this 
topic. It was supposed for a time, and is still supposed by some, that 
varieties from different wheat groups will not cross with each other. 
Often this is true if it is attempted to cross them directly; but it shows 
another great advantage of composite crossing that if these same varie- 
ties are first crossed with others of the same group, or with those of 
groups more nearly allied, the resulting progeny will cross more 
readily with that of a widely different group. For example, instead of 
attempting to cross a common wheat with a spelt, the desired result 



Common Common 



Club 



Spelt 



Spelt 




Hiihrid 2 



HvhricL 



Svhrid ^ 



Fig. 5.— Diagram showing hypothetical cross of wheat and spelt. 

would be more certainly and easily attained 1>y means of a composite 
cros.s .similar to that shown in the accompanying diagram (fig. 5), and 
at the same time there is a much better chance offered for selection 
because of the increased amount of variation thereby induced. 



77 

Through long, natural "in-and-in breeding'' the qualities of the 
variety have become specialized, as it were, in harmony with the con- 
ditions of the environment, and do not readily amalgamate with those 
of a widely different sort. But once produce variation among these 
qualities by means of crosses with allied sorts, and it becomes easier 
to blend them with those of very different sorts. 

SUMMARY. 

■ 1. As a foundation for rational wheat improvement, a knowledge is 
required of (1) the characteristics and needs of different wheat districts, 
and (2) the characteristic qualities of the natural groups of wheats. 

2. On the basis of conditions of soil and climate and the nature of 
the varieties adapted to these conditions, the United States may be con- 
sidered to be divided into eight wheat districts as follows: (1) Soft 
Wheat district, including mainly the Middle and New England States; 
(2) Semihard Winter Wheat district, including Ohio, Indiana, Illinois, 
Michigan, and a small part of Wisconsin; (3) Southern Wheat district, 
including approximately the Southern States; (4) Hard Spring Wheat 
district, covering the northern portion of the States of the Plains; (5) 
Hard Winter Wheat district, covering the central portion of the States 
of the Plains; (6) Durum Wheat district, covering the southern por- 
tion of the States of the Plains; (7) Irrigated Wheat district, including 
approximately the Rocky Mountain and Basin States, and (8) White 
Wheat district, including the Pacilic Coast States. 

3. Certain general needs, such as earl}^ maturity and greater yielding 
power, are common to all these districts and must be kept constantly 
in mind in connection with all efforts made to improve varieties. 
Other characteristics and needs are more special and are stated here- 
with under headings of the different districts. 

4. Soft Wheat district: 

(a) Present average yield per acre, about 14f bushels. 

(b) Chief varieties now grown: 

Fultz, Longberry, 

Fulcaster, Jones's Winter Fife, 

Early Genesee Giant, Red Wonder, 

Mediterranean, Gold Coin, 

Early Red Clawson, Blue Stem. 

(c) Needs of the grower: 

Harder-grained, more glutinous varieties. 

Hardier winter varieties for the most northern portions. 

Early maturity. 

Rust resistance. 

5. Semihard Winter Wheat district: 

(rt) Present average yield per acre, about 14 bushels. 

{b) Chief varieties now grown: 

Fultz, Valley, 

TVii.le, Nigger, 

Rudy, Dawson's Golden Chaff, 

Earlv Red Clawson. 



78 

(c) Needs of the grower: 
Hardness of grain. 
Rust resistance. 
Hardy winter varieties. 

6. Southern Wheat district: 

(a) Present average yield per acre, about Of bushels. 
(6) Chief varieties at present grown: 

Fultz, Everett's High Grade, 

Fulcaster, Boughton, 

Red May, Currell's Prolific, 

Rice, Purple Straw, 

(c) Needs of the grower: 
Rust resistance. 
Early maturity. 
Resistance to late spring frosts. 
Stiffness of straw. 

7. Hard Spring Wheat district: 

(«) Present average yield per acre, about 1.3 liushels. 

(b) Chief varieties at present grown: 

Saskatchewan Fife, Wellman's Fife, 

Scotch Fife, Hayne's Blue Stem, 

Powers Fife, Bolton's Blue Stem. 

(c) Needs of the grower: 

Early maturity. 
Rust resistance. 
Drought resistance. 
Hardy winter varieties. 

8. Hard Winter Wheat district: 

(a) Present average yield per acre, about 121 bushels, 
(ft) Chief varieties at present grown: 

Turkey, May, 

Fulcaster, Zimmerman, 

Fultz. 
(c) Needs of the grower: 

Drought resistance. 

Hardy winter varieties. 

Early maturity. 

9. Durum Wheat district: 

(«) Present average yield per acre, 11 5 bushels. 
{b) Chief varieties at present grown: 

Mediterranean, Fulcaster, 

Nicaragua, Turkey, 

(c) Needs of the grower: 

Macaroni varieties. 

Drought resistance. 

Rust resistance. 

Early maturity. 



79 

10. Irrigated Wheat district: 

(a) Present average yield per acre aljout 21 bushels. 
(6) Chief varieties at present grown: 

Sonora, Little Club, 

Taos, Defiance, 

Felspar, Amethyst, 

(c) Needs of the grower: 

Increase of the gluten content. 

Early maturity. 

11. Wliite Wheat district: 

(a) Present average yield per acre about 141- bushels. 
{b) Chief varieties at present grown: 

Australian, Foise, 

California Club, Palouse Blue Stem, 

Sonora, Palouse Red Chaff, 

Oregon Red Chaff, White Winter, 

Little Club. 
(c) Needs of the grower: 

Early maturity. 

Nonshattering varieties. 

Hardy winter varieties in the colder portions. 

12. The cultivated varieties of wheat are naturally divided into eight 
rather distinct groups, corresponding to eight botanic species, as fol- 
lows: (1) Common Bread Wheat {Triticumvulgare)^ (2) Club or Square- 
head {T. compactum)^ (3) Poulard {T. turgidum)^ (4) Durum {T. durwn), 
(5) Polish Wheat {T. polonimm), (6) Spelt {T. spelta), (7) Emmer {T. 
dicoecu7it)^ and (8) Einkorn {T. monococcum). The special character- 
istics of. these groups of wheats that are of prime importance in the 
work of wheat breeding are her^ given: 

(1) Common Bread Wheat group: 

(«) Excellence of gluten content for bread making. 
{h) Excellence of certain varieties for cracker making, 
(c) Yielding power of certain sorts. 
{d) Rust resistance (in some varieties), 
(e) Winter hardiness of certain varieties. 
(/) Resistance to drought of certain varieties. 
{g) Early maturity (in some varieties) . 

(2) C^lub or Square-head group: 

{a) Great yielding power. 
{h) Stiffness of straw. 

(c) Freedom from shattering. 

{d) Early maturity (in some varieties). 

(e) Drought resistance (in some varieties). 
(/) Excellence of certain sorts for making crackers and breakfast foods. 

(3) Poulard group: 

(f/) Excellence of certain varieties for making macaroni. 
{h) Resistance to orange leaf rust, 
(c) Resistance to drought. 
{d) Stiffness of straw. 



80 

(4) Durum group: 

{(() Excellence of gluten content for making macaroni and other pastes. 

( b) Resistance to drought. 

(r) Resistance to orange leaf rust. 

(5) Polish Wheat group: 

(«) Quality of gluten content for making macaroni. 
{b) Resistance to drought. 

(c) Resistance to orange leaf rust. 

(6) Spelt group: 

Desirable qualities — 

(o) Ability to hold the grain in the head. 

(b) Constancy in fertility. 

(c) Hardiness of certain winter sorts. 
Undesirable qualities — 

(d) Brittleness of head. 

(e) Ru.st liability. 

(7) Emmer group: 

Desirable qualities — 

(a) Ability to hold the grain in the head. 
(6) Drought resistance. 

(c) Resistance to orange leaf rust. 
Undesirable qualities — 

(rf) Brittleness of the head. 

(e) Adaptability only for spring sowing, as a rule. 

(8) Einkorn group: 

Desirable qualities — 

(a) Ability to hold the grain in the head. 
(6) Resistance to orange leaf rust, 
(o) Hardiness. 

(d) Resistance to drought. 

(e) Stiffness of straw. 
Undesirable quality — 

(/) Brittleness of the head. 

13. Wheats may also be grouped geographically. On this basis 
groups of varieties having certain special qualities are located approx- 
imatel}^ as follows: 

(a) Starchy white wheats: Pacific Coast and Rocky Mountain States, Chile, 

Turkestan, Australia, and India. 
{b) Amber or reddish grained wheats, also starchy: Eastern States, western 

and northern Europe, India, Japan, and Australia. 

(c) Excellence of gluten content for making the best bread: Northern and Cen- 
tral States of the Plains, Canada, eastern and southern Russia, Hungary, Rou- 
mania, and southern Argentina. 

(d) Resistance to orange leaf rust: Southern Russia, Mediterranean and Black 
Sea regions, and Australia. 

(e) Excellence of gluten content for making macaroni: Southern Russia, Algeria, 
and the Mediterranean region in general. 

(/) Stiffness of straw preventing lodging: Pacific Coast States, Japan, Turkestan, 

Mediterranean region, and Australia. 
ig) Yielding jiower (at least in proportion to size of head): Pacific Coast States, 

Chile, and Turkestan. 
(h) Nonshattering varieties: Pacific Coast States, Chile, Turkestan, Germany 

(spelts), and East Russia (emmers. ) 



81 

(i) Constancy in fertility: Germany (spelts) and southern Europe. 

(j) Early maturity: Japan, Australia, and India. 

(k) Resistance to drought and heat: East and South Russia, Kirghiz Steppes, 

Turkestan, and southern Mediterranean region. 
(0 Resistance to drought and cold: East Russia. 

14. Of the many wheat introductions made into this country in the 
past, the following are among* those of the greatest moment, and which 
have completely revolutionized the wheat industry in places: 

(a) Mediterranean, introduced first in 1819. 

(b) Fife wheats, introduced first into Canada and then into the northern States 

of the Plains. 

(c) Turkey wheat, first introduced into Kansas about twenty-five years ago from 

Taurida, in Russia. 

(d) The California Club, Australian, and Sonora, introduced into the Pacific coast 

States. 

15. Field experiments of the Department have shown that in the 
common bread-wheat group there is a very close constant relation 
between the autumn condition of the young plant on the one hand and 
winter hardiness and quality of grain on the other. 

16. Wheat is very susceptible to changes of environment, but espe- 
cially in regard to color, hardiness, and chemical composition of the 
grain. 

17. In general, regions possessing black prairie soils and character- 
ized by violent climatic extremes, especially extremes of heat and 
drought, produce wheats that are hardiest, have the hardest grains, and 
are the best in quantity and quality of gluten content. 

18. Considering all qualities, the best wheats of the world are of 
Russian origin, coming particularly from eastern and .southern Russia, 
the Kirghiz steppes, and Turkestan. Of Russian varieties so far 
known, the following are among the best, if not the very best: 

Arnautka, Turkey, 

Kubanka, Ghirka Spring, 

Ghirka Winter, Russian, 

Crimean, Buivola, 

Sarui-bug-dai, Kubanka Red Winter, 

Mennonite, Yx, 

Chernokoloska, Beloturka. 

19. The earliest ripening wheats are often dwarfed. The following 
varieties are among the best of this class: 

Yemide, Early Baart, 

Onigara, Early Japanese, 

Shiro-Yemidashi, Japanese No. 2, 

Kinta,nia, Nashi, 

Kathia, AUora Spring, 

Roseworthy, Stein wedel, 

King's Julnlee. 

4879— No. 24 «) 



82 

'20. The following varieties are among the best known of the durum 
and poulard groups: 

Arnautka, Galland's Hybrid, 

Kubaiika, El Safra, 

Beloturka, Petanielle noire de Nice, 

Chernokoloska, Volo, 

Medeah, Missogen, 

Sarui-bug-dai, Atalanti, 

Cretan, Nicaragua. 

21. Common bread wheats can not be depended upon to resist rust, 
but the best in this regard are probably the following: 

Turkey, Crimean, 

Pringle's Defiance, Oregon Club, 

Rieti, Odessa, 

Pringle's No. 5, Mennonite, 

jfashi. Velvet Blue Stem, 

Saskatchewan Fife, Sonora, 

Theiss, Prolifero, 

Bellevue Talavera, Mediterranean, 

Arnold's Hybrid, Deitz Longberry. 

22. Einkorns resist leaf rust completely, and emmers resist it to a 
high degree. 

23. Some of the very hardiest winter varieties so far tried in this 

country are: 

Turkey, Crimean, 

Yx, Ghirka Winter, 

Bearded Winter. 

24. Club wheats are usually soft-grained and tender sorts, adapted 

only to mild climates like that of California. Among the best of this 

group are: 

Little Club, Palouse Red Chaff, 

California Club, Chili Club, 

Herisson barbu, Sicilian Red Square-head, 

Herisson sans barbes. 

25. Some of the most popular and valuable wheats of our country 
have been produced by simple selection, though in some cases the indi- 
cations are strong that they were originally the result of natural 
crossing. The best known of such varieties are: 

Fultz, Rudy, 

Clawson, Wellman's Fife, 

Gold Coin, Currell's Prolific. 

26. Selection plays far the most important part in wheat breeding, 
and necessitates on the part of the experimenter a thorough knowl- 
edge of varieties and their relations to each other and to their envi- 
ronment. 



83 

27. Simple selection of individuals, however, for the improvement 
of the same variety can and should be practiced on every farm. Very 
little extra time or trouble is required, but the gain is great. 

28. Among the most valuable wheats of the United States that have 
been produced through hybridization are the following: 

Fulcaster, Pringle's Defiance, 

Gypsum, Pringle's No.5, 

Improved Fife, Hornblende, 

Quartz, Felspar, 

Ruby, Blount's No. 10, 

Jones's Winter Fife, Diamond Grit, 

Early Genesee Giant, Early Red Clawson, 

Early Arcadian, Early White Leader. 

29. For the most complete success in wheat improvement through 
hybridization it is necessary to practice composite crossing with 
parents selected from widely different wheat groups. 

30. The wheat plant is so closely self-fertilized in nature that the 
practice of composite crossing produces some most interesting and 
remarkable results. There is apparently no end to the variations 
exhibited by the sporting progeny in such cases, and, accompanied by 
discriminating selection, the possibilities of wheat improvement in 
this way are practically unlimited. 



INDEX OF VARIETIES. 



Page. 

Algerian 44, 4.5 

Allora Spring 43, 44, 4.5, 63, 81 

Alpha VO 

Alsace 44,4.5,61,63 

American 44, 45 

American Bronze 44, 45 

Ames 44, 45 

Amethyst . , 21, 44, 45, 69, 79 

Amidonnier. (^'eeEmme^.) 

Arnautka 19, 31, 44, 45, 62, 63, 81, 82 

Arnold's Hybrid 44, 45, 63, 82 

A six rangs 44, 45 

Assiniboine Fife 44, 45 

Astrakhan 32 

Atalanti 44,45,63,82 

Australian 22, 25, 40, 43, 44, 45, 79, 81 

Au.stralian Indian 44, 45 

Au.stralian Purple Straw 44, 45 

Baggi 44, 45 

Banat 28, 44, 45, 63 

Barletta 44, 45 

Barley wheats. {See Durum wheats.) 

Basalt 44, 45 

Bauchiger Weizen. {See Poulard wheats. ) 

Bearded Winter 44, 45, 62, 63, 82 

Bearded Winter Fife 72 

Bellevue Talavera 44, 45, 63, 82 

Belokoloska 44, 45 

Beloturka 15, 44, 45, 62, 63, 74, 81, 82 

Berthoud 44,45 

Bianchetta 44, 45 

Big English 44,45 

Big Frame 44, 45 

Black Spelt 74, 75 

Black Velvet 44, 45 

Bl(5 petanielle. (See Poulard wheats.) 

Blount's Fife 44, 45, 74 

Blount's No. 10 44, 45, 69, 70, 83 

Blue Stem 13, 16, 44, 45, 77 

Bolton's Blue Stem 17, 44, 45, 66, 78 

Boughton 15, 78 

Bread wheats 7, 

26, 28, 30, 31, 32, 33, 37, 43, 63, 71, 74, 75, 76, 79 

Buca Nera 44. 45 

Bucke ve 44, 45 

Budapest 39, 46, 47 

Buivola 28, 62, 81 

California Club 2.5, 63, 79, 81, 82 

Candeal Redondo 46, 47 

Canning Downs 14, 46, 47, 63 

Cape 46, 47 

Cartagena 46, 47 

Chernokoloska 46, 47, 62, 63, 81, 82 

Chcrnouska 46, 47 

Chiddam de Mars rouge 46, 47 

Chili 46, 47 

(;hili Club 22, 46, 47, 63, 82 

China Red 46,47 

China Tea 46, 47 

China White 46, 47 

Chinese 46, 47 

Clhubut 46, 47, 63 

Clawson 46, 47, 59, 65, 66, 71, 82 

Club wheats 22, 

23, 24, 28, 29, 37, 40, 43, 63, 73, 74, 75, 76, 79, 82 
Common wheats. {See Bread wheats. ) 

Composite wheats 30 

Countess 70 

Cretan 46, 47, 63, 82 

(Crimean 28, 46, 47, 62, («, 81 , 82 

Currell's Prolific 15, 46, 47, 78, 82 



Page. 

Dallas 46, 47 

D'Arblay's Hungarian 46,47,74 

Daruma" 46, 47, 63 

Dattel 46,47 

Dawn 70 

Dawson's Golden ChaflE 14, 39, 46, 47, 77 

Defiance 15,21,22,46,47,79 

Deitz 46,47 

Deitz Longberry 63, 82 

De la Basse 46, 47 

Diamond Grit 21, 46, 47, 72, 83 

Diehl Mediterranean 46,47,66 

Dinkel. (See Spelt.) 

Dividenden 46, 47 

Duro di Apulia 46,47 

Durum wheats 8, 15, 19, 2(i, 29, 

30, 31, 32, 33, 37, 40, 43, 60, 63, 72, 73, 74, 75, 79, 80 

Earlv Arcadian 46, 47, 72, 83 

Early Baart 46, 47, 63, 81 

Early Genesee Giant 13, 43, 46, 47, 71, 72, 77, 83 

Early Japanese 48, 49, 63, 74, 81 

Earlv May 43,48,49 

Earl V Red Clawson .... 13, 14, 48, 49, 65, 71, 72, 77, 83 

Earlv Rice 48,49 

Earlv White Leader 71,83 

Einkorn 35, 36, 37, 43, 48, 49, 63, 73, 79, 80, 82 

El Safra 48, 49, 63, 82 

Emmer 30, 33, 34, 35, 37, 43, 72, 73, 79, 80, 82 

English wheats, (.sve Poulard wheats.) 
Engrain. (See Einkorn.) 

Engrain double 36, 48, 49 

Entre Rios 48,49 

Epeautre 33 

Essex Red 74 

Everett's High Grade 15, 48, 49, 78 

Farquhar 48, 49 

Farrer's Durum 48, 49 

Felspar 21, 48, 49, 69, 70, 79, 83 

Fern.. 48.49 

Fife 16,21,28,31,38,65,67,81 

Flourelle 48,49 

Fluorspar 48,49 

Foise 23,2.5,79 

Frampton 48,49 

Frances 48,49 

Frankenstein 48, 49 

Fulcaster 13, 15, 18, 20, 28, 48, 49, 63, 70, 77, 78, 83 

Fultz 13, 

14, 15, 18, 39, 48, 49, 63, 65, 70, 71, 74, 77, 78, 82 

Galland's Hybrid 48,49,63,82 

German Amber 48, 49 

German Emperor 48, 49 

Gerstenweizen. {See Durum wheats.) 

Gharn( )vka 48, 49 

Ghirka 28,39 

Ghirkii Spring .56, 57, 62, 63, 81 

Ghirka Winter 58,62,63,81,82 

Giant Rye. {See Polish wheats.) 

Glasgow 38 

Glvndon 673 48,49 

Glvndon Sll 48,49 

Gold ( -oin 13, 16, 48, 49, 66, 77, 82 

Golden (Toss 48,49,71 

Golden Cross Jr 71 

Goldene Aue 48, 49 

GoliU'u ( iate Club '-'2 

Graf Walderdorff's Regenerated 48, 49 

Granite ^9 

Grass ( .sV'C Odessa. ) 

G viisum 48, 49, 69, 74, 75. 76, 83 

Hairkani 48, 49 

85 



86 



Page. 

Hallett'f? Pedigree 48, 49 

Hardcastlc White 74, 75 

Hayne's Blue Stem 17, 48, 49, 66, 67, 78 

Herisson barbii 50, 51, 63, 82 

Herisson sans barbes 50, 51, 63, 82 

Hickling 50, 51 

Hopetowu 50, 51 

Hornblende 50, 51, 69, 74, 75, 76, 83 

Hudson's Early Purple Straw 50, 51 

Hundred Fold 30 

Hungarian Red 74, 75 

Hungarian White 74 

Hunter's White 74 

Igel mit Grannen 50, 51 

Igel ohne Grannen 50, 51 

Imperial 50, 51 

Improved Fife 50, 51, 61, 69, 70, 74, 75, 76, 83 

Iron Straw 71 

Japanese No. 1 50,51,63 

Japanese No. 2 50, 51, 63, 81 

Japanese No. 4 50,51,63 

Jejar de Valencia 50, 51 

Jerusalem Rye. (See Polish wheats.) 

Jones's Square-head 50, 51 

Jones's Winter Fife 13, 50, 51, 71, 72, 77, 83 

Kastamuni 50, 51 

Kathia 60,51,63,81 

Khel 50,61 

King's Jubilee 43, 50, 51, 63, 81 

Kinney 50, 51 

Kintama 50,51,63,81 

Krasnokoloska .60, 51 

Kubanka 19, 31, .60, 51, 61, 62, 63, 81, 82 

Kubanka Red Winter 62, 81 

Kubb 50, 51 

Ladoga 50, 51 

Lai 50,61 



Lamed 50, 51 

Lancaster .50, 51, 63, 66, 70, 71 

Lehigh 50, .51 

Linaza 50, 61 

Little Club 21, '24, 25, 43, 50, 51, 60, 63, 79, 82 

Longberrv 13, 77 

Lost Nation 50,61 

Macaroni wheat. {See Durum, Poulard, 
and Polish wheats.) 

Mainstay 74, 75 

May 15,18,78 

McKissick's Fife 50, 61 

Mealy 52, 53 

Medeah 52,53,63,74,75,76,82 

Mediterranean 13, 

19, 20, 28, 38, .52, 63, 63, 71, 77, 78, 81, 82 

Meekins 52, 63 

Melka 52, 53 

Mennonite 52,53,62,63,81,82 

Minnesota Fife 52, .53 

Miracle 30 

Mirado 62, 63 

Missogen 52,63,63,82 

Moscow 52, 53 

Mundia 52, 53 

Murcia 52, .53 

Muzaffarnagar .52, 53 

Nab-el-bel 52,53 

Nashi 52, ,63, 63, 81, 82 

Nicaragua 15, 19, 20, 31, 32, 40, 63, 78, 82 

Nigger 14, 52, 63, 77 

Noe 52,63 

Nonetto de Lausanne 52, 53 

Nonpareil 52,53 

No. 6. ( See Gold Coin. ) 

Odessa 39,52,63,62,63,82 

Onigara 52,53,63,8] 

Oregon Club 52, .53, 63, 82 

Oregon No. 10 70 

Oregon Red Chaff 23,25,79 

Palouse Blue Stem 16, 

22, 24, 26, 40, 42, 52, 63, 60, 61 , 79 

Palouse Red Chaff 22, 25, 63, 79, 82 

Pedigree Red 74, 76 

Pedigree White 74 

Penquite's Velvet Chaff 52, 63 

Percv 70 

Petanielle noire de Nice 62, 53, 63, 82 

Pilli 52, 53 

Pissi Hydrabadi 52, 53 



Page. 

Polba. {See Emmcr.) 

Polish wheat.... 31,32,33,37,43,52,53,63,73,79,80 

Poole 14, 39, 52, 63, 59, 77 

Poulard wheats 8, 

26, 29, 30, 31, 37, 43, 60, 63, 73, 74, 75, 79 

Power's Fife 17, 52, 53, 66, 78 

Preston 70 

Pringle's Best 69 

Pringle's Defiance 62, 53, 63, 69, 82, 83 

Pringle's No. 4 69 

Pringle's No. 5 52, 53, 63, 69, 82, 83 

Pringle's No. 6 69 

Probsteier 52, 63 

Progress 70 

Prolifero 52, 63, 63, 82 

Prophet 52, 53 

Propo 22, 54, 55 

Pulavka 54, 55 

Purple Straw 15, 40, 54, 55, 78 

Quartz 54, 55, 69, 74, 83 

Rattling Jack 54, 55 

Red Bearded 54,55 

Red Chaff. {See Oregon Red Chaff and Pa- 
louse Red Chaff.) 
Red Chaff Club. {See Palouse Red Chaff.) 

Reddish White Bearded 54,55 

Red Fife 54, 55 

Red German Bearded 75 

Red May 16, 78 

Red Provence 54, 55 

Red Spring 54, .55 

Red Tyrol 54,55 

Red Winter 54, 55, 62, 63 

Red Wonder 13, 77 

Rice 16,64,56,78 

Rieti 54, 55, 63, 82 

Rio Grande 64,55 

Rivett's Bearded Spelt 75 

Rivet wheats. (iSee Poulard wheats.) 

Roseworthy .- 54, 55, 63, 81 

Ruby 69,70,83 

Rudy 14, 23, 54, 65, 66, 77, 82 

Russian 62, 81 

Russian Hard 54, 55 

Russian Spring 54,55 

Russian Velvet 71 

Rve Wheat -. 54,55 

Safeed 54,. 55 

Saida 54, 55 

Saldom6 54,66 

Salt Lake Club 22 

Samara 64, 65 

Sandomir 54, .55, 62 

Saratov 54, 55 

Sarui-bug-dai 54, 55, 62, 63, 81, 82 

Saskatchewan Fife. . . . : 17, 54, 55, 63, 65, 78, 82 

Saumur Winter 64, 55 

Scotch 38 

Scotch Fife 17,54,66,61,65,78 

Seneca Chief 54, 55 

Seven-headed ■. 30,54,55 

Shirosawa 54, 55 

Shiro-yemidashi 54, 55, 63, 81 

Sicilian Red Square-head 54, 55, 63, 74, 82 

Sindhi 56,.57 

Sonora 21, 22, 25, 40, 66, 67, 63, 79, 81 , 82 

Soules 56,67 

Spelt 33, 34, 35, 37, 43, 72, 73, 76, 79, 80, 81 

Spelz. {.See Spelt.) 

Spring Ghirka (.see also Ghirka Spring) .56, 57 

Square-head 75 

Square-head wheats. (See Club wheats.) 

Steinwedel 66, 67, 63, 81 

Swamp 56, .67 

Taganrog ,. 56, 57 

Talavera 56, 57, 74 

Tangarotto 56, 57, 63 

Taos 21, 66, 57, 79 

Tasmanian Red 56, 57, 63 

Theiss 28, 39, 56, 57, 63, 82 

Tourmaline 56, 57, 74 

Touzelle 56, 57 

Trimenia 66, 57 

Tritieu m 26, 26 

Triticum compact am 22, 26, 28, 29, 79 

Triticum cowpo.srtWHi 30 

Triticuvi dicoccum 26, 30, 33, 34, 79 



87 



Page. 

Triticim durum 8, 26, 29, 30, 79 

Triticum inonoco( cum 26, 35, 79 

Triticu m polonicum 26, 32, 79 

Triticum spelta 26,33,79 

Triticum turgidum 8, 26, 29, 79 

Triticum vuigare 7, 8, 26, 29, 79 

Turkey 17, 

'18, 20, 21, 28, 31, 39, 56, 57, 59, 60, 62, 63, 78, 81, 82 

Tuscan 56, 57 

Ulka 28,39,62 

Urtoba 56, 57 

Valley 14,56,57,63,77 

Varesotto 56, 57 

Velvet Blue Stem 16, 28, 31, 56, 57, 63, 65, 67, 82 

Velvet Chaff 56, 57 

Victoria d' Aiitomne 56, 57 

Victorian Defiance 56, 57 

Volo 56, 57, 63, 82 

Vyssoko-Litovsk 56, 57 

Walla Walla - - 56,57 



Page. 

Walker 56, 57 

Ward's Prolific 56,57,74 

Ward's White 74, 75, 76 

Wellman's Fife 17, 58, 65, 66, 67, 78, 82 

White Chiddam 74, 75 

White Clawson. (See Clawson.) 

White Michigan 39 

White Polish 32 

White Tuscan .58 

White Winter 25,58,79 

Wild Goose 40, 58, 63 

Winter Fife. (See Jones's Winter Fife.) 

Winter Ghirka (see, also, Ghirka Winter)... 58 

Wonder 30 

Wyandotte Red 58 

Yemide 43, 58, 63, 81 

Yx 58, 62, 63, 81, 82 

Zaruta 58 

Zimmerman 18, 58, 74, 78 



o 



Bulletin No, 25. 



V. p. p.— 78. 



U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

B. T. GALL-bwAY, Chief. 



SOME DISEASES OF NEW ENGLAND CONIFERS: 

A PRELIMINARY REPORT. 



BY 



HERMANN VON SCHRENK, 

Instructor in Botany^ Henry Shaw Sr/iool of Botany, 
Special Ayent, Division of Vegetable Physiolocfy and Pathology. 




WASHINGTON: 

GOVERNMKNT PRINTING OFFICE. 
I y oo. 



DIVISION OF VEGETABLE PHYSIOLOfn' AND PATHOLOGY. 



SCIENTIFIC STAFF. 

B. T. Galloway, Chief of Division, 
Albekt F. Woods, Assistant Chief. 



ASSOCIATES. 



EmviN F. Smith, 
Mertox B. Waitk, 
Newton B. Piekce, 
Herbert J. Webber, 
M. A. Garleton, 

r. TI. DoKSETT, 



OsCAli LoEW, 

AVm. a. Orton, 
Ernst A. Bessey, 
Flora W. Patterson, 
Hermann von Sciirenk,' 
Marcts L. Fj.oyo.^ 



IN charoe of laboratories. 

A-lbert F. Woods, Plant PhysioJogij . 

Erwin F. Smith, Plant Pathology. 

Newton B. Pierce, Pacific Con. <it. 

Herbert J. Webber, Plant Brcecling. 

Oscar Loew,-'' Plant Nutrition and Fermentation. 



1 Special agent in clmrgc of studies of forcst-trcc diseases, cooperating with tlie Division of Forestry, 
U. S. Department of AKriculturc, and the Henry Shaw School of Botany, St. Louis, Mo. 
-Detailed as tobacco expert, Division of Soils. 
•*In charge of the tobacco fermentation investigations of tlic Division of Soils. 



Bulletin No. 25. 



V. P. P.— 78. 



U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

B. T. OALLOWAY, Chief. 



SOME DISEASES OF IW ENGLAND CONIFERS: 

A PRELIMINARY REPORT. 



BY 



HERMANN VON SCHRENK, 

Instructor in Botany, Henry Shaw School of Botany, 

Special Agent, Division of Vegetable Physiology and Pathology. 




WASHINGTON: 

GOVKKNMRNT PRINTING OFFICK. 
1900. 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 
Division of Vegetable Physiology and Pathology, 

^Yashin(Jton, D. C, August 8, 1900. 

Sir: I respectfully transmit herewith a paper prepared by Dr. Her- 
mann von Schrenk, special agent of this Division, on Some Diseases of 
New England Conifers. The investigations described were carried on 
in cooperation with the Division of Forestry of this Department and 
the Shaw School of Botany, of St. Louis, Mo., and are of special 
interest at this time, in view of the increasing demand for information 
on forest problems. I respectfully recommend that the paper be pub- 
lished as Bulletin No. 25 of this Division. 

Dr. von Schrenk desires acknowledgment on his behalf to the fol- 
lowing persons for courtesies shown him and assistance rendered in 
his work: Mr. Austin Gary, of the Berlin Mills Company; Profes- 
sor Harvey, of Orono, Me.; Mr. S. Boardman, of the Bangor Com- 
mercial; and Mr. Cram, of the Bangor and Aroostook Railroad. 

Respectfully, 

B. T. Galloway, 

Chief of Dlclsio)). 
Hon. James Wilson, 

Secretary of Agriculture, 



CONTEXTS. 



Page. 

Introduction 9 

Necessity for studying the diseases of forest trees 9 

Where the investigations reported were made 10 

Previous work on diseases of trees 11 

Kinds of fungi growing on forest trees and their relation to forest problems 11 

Extent of destruction 12 

External evidences of decay 12 

Relation to insect attacks 13 

Scope of this report 14 

New England forests 15 

Vegetative conditions 15 

Red Spruce 15 

White Spruce 16 

Balsam Fir 17 

Hemlock 17 

Arbor Vit^e 17 

W^hitePine 18 

Tamarack 18 

Polyporus scJw:einitzii Fr 18 

Occurrence 18 

Structure of diseased wood 19 

Fruiting organ 20 

Effect of fungus on the tree 23 

Trees attacked 24 

Methods of combating this fungus 24 

Fohjporux pinicola (Swartz) Fr 24 

Occurrence 24 

Structure of diseased wood 25 

Fruiting organ 29 

Trarnetcs pin i ( Brot. ) Fr. forma abietis Karst 31 

Occurrence 31 

Destruction of spruce wood 32 

Destnution of fir wood 35 

Destruction ( )f tamarack wood 3.) 

Fniiting organ 3(5 

Hymenium "^0 

Polyporm .vdfumis ( Bull. ) Fr 40 

Occurrence "^^ 

Structure of diseased wood "**^ 

]\Iiimte changes in the wood "*' 

Fruiting organ 

5 



6 CONTENTS. 

Page. 

Poli/poritti subacldm Peck 44 

Occurrence 44 

Structure of diseased wood 45 

Fruiting organ 48 

Remedies 49 

Other diseases 49 

Polyporus vaporarius (Pers. ) Fr 49 

Polyporus annosus Fr 49 

Agaricus melleus Yalil 50 

Conclusion 51 

Explanation of plates ■. 53 



ILLUSTRATIONS. 



PLATES. 

Page 
Plate I. Fig. 1. — Sporophores of Polyporm schweinitzii Fr. Fig. 2. — Polyporus 
volvatus Peck, growing from holes made in the bark by Dendrodo- 

rms sp ^6 

II. Log of Balsam Fir showing decay caused by Polyporus schweinitzu Fr. 56 

III. Log of White Spruce showing early stage of decay caused by Poly- 

porus pinieola (S wartz ) Fr 56 

IV. Log of White Spruce showing advanced stage of decay caused l)y 

Polyporus pinieola (Swartz) Fr 56 

V. Sporophores of Polyporus pinieola (Swartz) Fr 56 

VI. Fig. 1.— Red Spruce: Early stage of the decay caused by Tramefes 
pini forma abietis. Fig. 2.— Red Spruce: Advanced stage of the 

decay caused by Tramcies pini forma abietis 56 

VII. Log of Balsam Fir showing decay caused by Trametes pini forma 

abietis 56 

VIII. Fig. 1 early and fig. 2 late stage of decay of Larch caused by Trametes 

pini forma abietis 56 

IX. Polyporus subaddus Yk., Polyporus pinieola (Swartz) Fr.,and Trametes 

pini (Brot.) Fr. forma abietis Karst 56 

X. Work of Polyporus pinieola (Swartz) Fr. and Trametes p)im (Brot.) Fr. 

forma abietis Karst 56 

XL Stages of decay induced in Spruce by Pohjporus subaddus Pk. and 

Polyporus sulfureus ( Bull. ) Fr 56 

XII. Various forms of sporophores of Trametes pini (Brot.) Fr. forma 

abietis Karst 56 

XIII. Block of White Spruce wood showing injury caused by Polyporus 

sulfurexis 56 

XIV. Fig. 1 early stage and figs. 2 and 3 successively later stages of the 

decay caused in White Spruce by Polyporus subaddus Peck 56 

XV. Fig. 1.— Cross section of log of Spruce showing decay caused by Poly- 
porus subaddus Peck. Fig. 2. — Resupinate form of sporophore of 
Polyporus subaddus Peck on Spruce log 56 

TE.XT FIGURES. 

Fig. 1. Polyporus schvjeinitzii Fr. growing on a fallen Fir 21 

2. Cross section of Spruce wood showing masses of mycelium of Polyporus 

jnnicola (Swartz ) Fr 28 

3. Base of Spruce branch, showing its resistance to the attack of the 

mycelium of Polyporus subaddus Pk •*' 

7 



SOME DISEASES OF NEW ENGLAND CONIFERS. 



INTRODUCTION. 

NECESSITY FOR STUDYING THE DISEASES OF FOREST TREES. 

Very little attention has been paid to the study of diseases of forest 
trees in the United States up to this time, and the reasons are obvious 
enough. Up to within a few years the supply of standing- timber of 
all kinds has been so large that a few diseased trees, more or less, scat- 
tered over wide areas were of little account. The lumberman cut down 
the sound trees and paid no attention to such as he recognized to be 
of inferior value. The situation has changed within the last decades, 
and a wide-felt demand has arisen among all classes of people for a 
more economical and rational treatment of the existing forest lands, 
and for reestablishing forests on denuded areas. In the primeval 
forest the trees diseased because of fungous or insect attack were 
ignored. They were few in comparison with sound trees, and the 
price of a single tree was very low. At the present time, with a marked 
appreciation in the value of timber, the agencies which injure trees for 
timber are of more immediate interest to the owners of woodlands. 
At this time the extent to which insects and fungi destroy trees can only 
be guessed at. Their work of destruction goes on silently here and 
there in the forest, and does not attract the attention of the casual 
observer as do careless lumbering or forest fires. If the dead and 
dying trees in a forest could be collected, they would represent a con- 
siderable percentage of the total forest. Forest fires are already not 
so common as they used to be, and the lumberman of to-day is beginning 
to understand that more can be realized from a given forest tract by 
rational treatment than by indiscriminate cutting. Insects and fungi, 
and othei- harmful agencies of less importance, are being studied with 
the aim of arriving at a more complete understanding of their manner 
of working. 

From \t^ first growth until it falls a tree is subject to attacks of a 
large luunber of insects and fungi, often resulting in stunted growth 
or death. In many cases the injury is to the wood alone; the diseased 

tree may remain standing for many years, and may be useful as a shade 

y 



^0 

tree, but its value for timber has been destroyed. Besides the insects 
and fungi, diseases which may be characterized as physiological are 
not unconmion. They may be due to an insuificient supply of light, 
heat, water, or food, etc. Often insects and fungi act in conjunction 
with other unfavorable agencies, and it then becomes a matter of con- 
siderable difficulty to ascertain the true cause of the disease. The 
present paper deals onl}^ with diseases due to fungi. 

The mycelia of fungi attack living trees as well as dead ones. When 
on living trees they grow either in the living parts, the roots, leaves, 
bark, or newer wood cells, or in the dead parts, the heartwood of the 
roots, trunk, and branches. The character of the injury which the 
mycelium causes depends much upon its place of growth, whether on 
the leaves or within the wood. Injury to the leaves may often be very 
great, as is the case with fungi like the Erysiphece^ TJredinecB^ Exoas- 
cece, and others. The injury caused by those which grow in the living 
bark or cambium, like the species of NectHa^ for instance, is very large. 
A large class of fungi flourishes within the heartwood of trees, 
growing into it through a branch or some wound, and in some cases 
through the roots. The effect of their growth is to destroy the heart- 
wood, iilling it with holes or turning it to a brittle substance which has 
none of the properties of ordinary wood. These changes weaken the 
trunk, and at some period or other the tree is broken by the wind. 
T lose forms which enter through the roots may kill the latter first, and 
t'lus cause a tree to fall. The wood is then rapidly destroyed by a large 
variety of fungi and insects. It is therefore to the interest of the for- 
ester who grows trees for their wood to determine what fungi so 
affect the trees as to render the wood unfit for lumbering purposes. 

In Europe, where forests have been grown for many years, the 
importance of understanding the diseases of forest trees has long been 
recognized, as is well shown by the works of Hartig, Tubeuf , Marshall 
Ward, Frank. Nypels, and others. These show that it is possible to 
prevent the growth of many of these fungi by destroying their fruiting 
bodies, and, in general, by bringing about conditions unfavorable to 
their growth and development. In order that this may be properly 
and successfully done, it is first necessary to know what the destructive 
fungi are and where and how they live. It was with this end in view 
that the writer spent several months during the year 1899 in the for- 
ests of Maine. A preliminary survey was made of the forests of that 
State, and the results are here presented in preliminary form. 

WHERE THE IXVESTIGATIONS REPORTED AVERE MADE. 

The region about Houlton in Aroostook County was first visited, 
then the territory north of Moosehead Lake, and during September 
the region about the Rangeley Lakes. A large part of the summer was 
spent on the coast at Linekin (near Boothbay Harbor, Maine), where 



11 

the extensive spruce groves of both older and younger trees presented 
excellent opportunities for a study of the commoner forms. Collec- 
tions of wood and fungi were made at all points visited. The basis of 
this report consists of lield notes made in the regions visited, together 
with brief descriptions of the various forms of diseased wood. When 
the opportunities permitted, inoculations were made, by means of 
spores and mycelia, the results of which will not be apparent for many 
years. 

PREVIOUS WORK ON DISEASES OF TREES. 

Practically no work has so far been done on the diseases which affect 
the woody parts of the forest trees of the Northeastern States. Many 
descriptions have been published of the fungi whicU grow on these 
trees, but these deal mostly with the fruiting portion of these fungi 
and but rarely with the effects which they l)ring aliout in their sub- 
stratum. Nearly all of the fungi of this class have been very 
thoroughly studied by Hartig^ in Germany, and many of the conclu- 
sions of the present paper correspond with the results which he 
obtained. His studies, however, were confined to the effects of the 
fungi on the forest trees of Germany. The only notes on the forest 
fungi of America which the writer was able to find are those in 
Sargent's Silva of North America.^ A nimiber of the commoner fungi 
are there referred to briefly. The majority of these, however, are leaf 
fungi, viz, Dasyscyj^ha willkommii R. Hartig. ''said to occur in the 
United States, etc.," the various species of Peridermium, and a few 
others. 

The catalogues of floras report many of the fungi herein noted, but 
the mere record of the occurrence of a fungus at one or more locali- 
ties is of so little value in this connection that it was not considered 
worth while to present even an enumeration of them here. 

KINDS or FUNGI GROWING ON FOREST TREES AND THEIR 
RELATION TO FOREST PROBLEMS. 

Of the fungi found growing on the wood of the coniferous trees 
but a small number bring about changes which completely destroy the 
wood. Many fungi grow on the bark of a dead tree or their mycelia 
penetrate into the living bark, where they flourish, but go no deeper. 
Others, again, grow in the bark and sapwood of trees after the latter 
have died, and in so doing destroy these parts. A third class grows in 
the heartwood only, or in heartwood, sapwood, and bark, whether the 
trees are alive or dead. Several of the last-mentioned class attack 
living trees and slowly ])ring about changes which ultimately result in 

^Hartij:, R. Zersetzungserscheinungen des Holzes dor Nadelholzbaumo und der 
Eidie. 1.H78. 
" Sargeut, C. S. Silva of North Ameriai. 12:5,26. 1898. 



12 

death. Others grow within the heartwood, in which case the tree maj'' 
remain alive as long as the trunk is strong enough to uphold the 
crown of l)ranches. Some of these fungi can grow both as saprophytes, 
i. e. , on dead wood, or as facultative parasites on living trees. In the 
following only those fungi are considered which so destroy the wood 
of the trees as to render it unlit for lumbering purposes. 

The fungi to be described all belong to the PohjjWTei. Their sporo- 
phores form during the summer, and in several cases grow on dur- 
ing the winter months. They discharge their spores into the air 
in vast numbers, and these are carried to great distances by the 
wind. The spores germinate, under favorable conditions, in a 
wound or on the roots, and the mycelium makes its way into the 
inner parts of the tree, where it flourishes for a shorter or longer 
period, when the fruiting organ is again formed. The length of time 
which is required for the formation of the sporophores is variable, 
and is known for very few species. In some cases the sporophores 
grow onl}^ on the living trees; in other cases, again, they form for 
many years on the dead stumps or fallen trunks. Seasonal variations 
are to be met with. Some years, when it is exceptionally moist, the 
fruiting forms grow in great numbers, while during a dry summer 
very few are to be found. 

EXTENT OF DESTRUCTION. 

The amount of destruction which these fungi do is actually very 
large. As has been said, the casual observer does not note a dead tree 
here or there, but he is struck with the destruction wrought by forest 
fires. In certain localities the older trees are likely to become infected 
by one fungus or another, and it is a common saying of the lumberman 
that "the older trees are always rotten." If all the dead trees in a 
forest could be brought together, their number would truly be a sur- 
prise to lumbermen, the majority of whom have no appreciation of 
even the approximate destruction which is wrought in the forests in 
this way. Without extended cruisings it would be hazardous to make 
any more definite statement for the present than this: The number of 
dead and decayed trees is sufiiciently large to represent a considerable 
loss in capital, and warrants making efiorts to prevent the destruction 
of what would be valuable timber if harvested in time. 

EXTERNAL EVIDENCES OF DECAY. 

It is often a matter of considerable importance to recognize which 
trees in a forest have been attacked by fungi, so that these trees may 
be removed before the}^ are completely destroj^ed and before there is 
any opportunity for the formation of sporophores. Trees which are 
in an advanced state of decay can usually be recognized by the fact 
that they have the fruiting organ of one or another fungus growing 



13 

on their roots, trunks, or branches. The lumberman of the present 
day naturally tries to avoid trees which are rotted, and his method of 
diagnosis consists in pounding the trunk to see whether it sounds hol- 
low. Hollowness, however, is not always a sign of disease, as many 
trees are hollow at the base and sound above, and therefore satisfy the 
demands of the lumberman at least in part. A test in use all over the 
country is the presence of what are variously known as punks, conchs, 
punk knots, resin knots, etc. A punk is usually the sporophore of 
Trametes jnni, or some other large hoof -shaped sporophore. The other 
terms are more often applied to swellings which occur at points where 
a dead In-anch stub is found on the tree. In diseased trees of Pine or 
Spruce the turpentine is driven from the wood ]>y the action of the 
mycelium of this or that fungus, and passes on before it, up the heart- 
wood of old branches and out through them, forming resinous lumps, 
which harden in contact with the air. These lumps occur at all heights 
on the trunk and increase in size from year to year. The accumulation 
of these resinous masses prevents the normal healing of the wound or 
healing over of the stub of the branch, and results in the formation 
of a marked protuberance at that point, commonly called a knot, with 
its various modifications. The turpentine often drips from such a spot 
or runs down the bark in small streams. It may be many years before 
the decomposition within the tree advances sufficiently to enable sporo- 
phores to form, and a system of prophylactic treatment must take into 
account phenomena such as these to aid in detecting diseases in their 
early stages. What has been said with reference to these resin accu- 
mulations applies particularly to fungi like Trametes jnni {^vot.)FY. 
and its form ahletis Karsten, to Polyporm schweinitzU, and Pohjjyorm 
sulfurcm^ and one or two others not yet definitely identified. 

RELATION TO INSECT ATTACKS. 

The nature of the fungus injury is often very obscure, and there are 
so many factors which have to be considered in tracing the nature of 
any one disease that the results of the present paper are but fragmen- 
tary, and it is very probable that they will be modified largely by 
future discoveries. The intimate relationship which exists between 
the attacks of insects on the one hand and fungi on the other nuist be 
pointed out. There are without doul)t many fungi which find their 
way into the wood of trees through the holes which l)oring insects have 
made in the bai-k. The injury which the insect makes may be very 
slight, but it has opened the way for the action of the fungus, which 
may be very destructive. An example of this kind is to be found in that 
most curious of all the Poh/porel^ Poh/ponis volvatm Peck. This grows 
on the trunks of spruces which have been attacked by various spe(•ie^^ of 
boring beetles, notably species of Dcndroctonus. These be(»tles bore 
throuirh the bark into the cambium laver. The fungus enters through 



14 

these holes and grows in the sapwood of the tree, destroying it in a few 
mouths. Whether it grows there while the tree is still alive, and what 
its possible relations may be to the Dendroctouus, are problems yet to 
be solved. In many parts of the Maine woods every tree where the 
beetles had been or were still active was covered with the rounded 
fruiting organs of this Polyporus. (See PI. I, fig. 2.) Their association 
with this Polyporus offers a promising field for study. The holes made 
by the beetles allow the spores of several other fungi to enter, notably 
those of Poly poTUH pi ni cola. These germinate and grow throughout 
the heartwood, rendering it worthless in a very short period. 

The possible role which beetles and boring larvaB may play in carry- 
ing the spores of a fungus from one tree to another will be referred to 
below. These few instances will serve to show that it is all important 
that a study of the insect and fungus enemies of a tree should be made 
hand in hand. 

There are grave inherent difficulties in deteimining the exact cause 
of death of a large tree, for there are many factors which may influence 
its growth so that the tree becomes weakened. There is a widespread 
opinion that insects or fungi will not attack an absolutely healthy tree, 
but that the latter must be more or less weakened before such an 
attack takes place. That this is not always the case need hardly be 
said, but the mere fact that a fungus is growing in the tree or an insect 
is at hand upon it is no positive proof that one or the other is the 
active agent in bringing about its death. Such evidence, particularly 
if oft repeated, will become very valuable when taken in conjunction 
with other proofs. 

SCOPE OF THIS REPORT. 

In the following a number of fungi will be described, together with 
the characteristic changes which their mycelia induce in the wood of 
the trees in which they grow. These fungi were found again and 
again, always associated with the forms of decay ascribed to them, and 
never was such decay found without the fungus in question, or with- 
out a mycelium from which the fruiting portion of the fungus devel- 
oped. These fungi occurred on all coniferous forest trees, with few 
exceptions. Some of them started in the living trees and caused the 
heartwood to decay. They were found in large numbers destroying 
trees injured by insects, and on some tracts where fire had swept 
through the woods and had injured the bases of the tree trunks sev- 
eral of them had gained a foothold and had destroyed every tree thus 
injured. The principal ones met with were: Pohjporus sclnoeinitzii 
Fr.; Polypmnis pnnicola (Swartz) Fr., Trametes pini (Brot.) Fr. forma 
alietk Karsten; Pohjporm mlfnrew (Bull.) Fr.; and Polyjwrus suh- 
acidns Peck. A number of doubtful forms will be mentioned near the 
end of this report. 



15 

NEW ENGLAND FORESTS. 
VEGETATIVE CONDITIONS. 

The original forests of most of the New England States are gone. 
The White Pine, which at the advent of the white settler formed such 
a large part of the forests, is present in any large quantity only in the 
most inaccessible places and elsewhere as ripe timber only in isolated 
spots. The chief forest trees from the lumberman's standpoint are the 
Red Spruce and the WhitQ Spruce. Millions of feet of Red Spruce 
lumber are now being cut year after year in the States of Vermont, 
New Hampshire, and Maine. The time is not far distant, however, 
when the stand of spruce timber will be in a similar condition to that 
in which the White Pine is now. 

The conditions which prevail in the forests of Maine and New Hamp- 
shire can be touched upon only in so far as they relate to the presence 
of and probable influence on the diseases which form the basis of this 
report. The forests are usually moist. The forest floor is covered 
with a large variety of mosses, which hold water very readily. Sphag- 
num covers many square miles. Springs and brooks are abundant 
everywhere. The annual rainfall, often very heavy during the spring 
and summer months, accounts for the general humidity of the air. 
Near the coast the fogs keep the woods moist for a large portion of 
the growing season. The summer season is usually comparatively 
short, but while it lasts very warm days are not uncommon. Warmth 
and humidity, chiefly the latter, are very influential in promoting the 
growth of many saprophytic as well as parasitic fungi. 

Before describing the various fungi and their efl'ects, it may be well 
to say something of the trees which are affected by these fungi. 

RED SPRUCE. 

Foremost among the coniferous trees of New England at the pres- 
ent time is the Red Spruce, Picea ruhens Sarg. (P. mariana (Mill.) 
B. S. P., P. nigra Link). It is a tall, stately tree, which grows to be 
70-80 feet (21-2^ meters) high and 2-3 feet (0.6-1 meter) in diameter. 
It occurs all over northern New England, together with the Balsam 
Fir and White Pine. Sargent says of this tree:^ 

Picea ru})ens, which is the principal timber spruce of the northeastern United 
States, and, with the exception of the White Pine, the most valuable coniferous 
timber tree of the region which it inhabits, produces light, soft, close-grained wood, 
which is not strong nor durable when exposed to the weather. It is pale, slightly 
tinged witli red, with paler sapwood about two inches thick, and a satiny surface 
* * *. Now that the most valuable White Pine has been exhausted in the forests 
of the Northeastern States, the Red i^pruce is their most important timber tree, and 
immense (piantities of its hun1)er are manufactured every year from trees cut in 
Maine, New Hampshire, Vermont, and northern New York. * * * 

' Sargent, G. S. Silva of North America. 12:35. 1898. 



16 

The wood of the Red Spruce is used for construction, and thousands 
of trees of all sizes also find their way to the pulp mills for the manu- 
facture of paper. During the summer of 1899 several large new mills 
were building in central Maine, one of which was expected to con- 
sume 300 tons of spruce wood daily. In a recent article in The 
Forester, Mr. Lyman, of the International Paper Company, discusses 
at length the use of this spruce for making pulp. 

The tree is one of moderately slow growth. It reproduces itself 
well from seed, and grows up readily to replace the original stand of 
timber. In the forest, when growing in close stands, the lower 
branches die gradually and break off, leaving dead stubs which, in the 
case of larger branches, offer inviting spots for the entrance of fungus 
spores for several years after the fall of the dead branch. Attention 
has already been called b}^ the writer to the manner in which diflferent 
trees heal the wounds caused by dead branches.^ 

There are resin channels scattered through the summer wood. Their 
number varies considerably in the individual tree. In some trees 
there are but one or two in a given ring, while six or eight years 
later there may be two or three dozen. 

WHITE SPRUCE. 

The White Spruce, Plcea ccmadensis (Mill.) B. S. P. (P. alha Link), 
a very much more stately tree than the Red Spruce, grows to a height 
of 150 feet (about 16 meters), with a trunk 3 to 1 feet (0.9 to 1.2 meters) 
in diameter. In the Northeastern States it is found in abundance, 
especially along the coast, and on some of the islands it is the only tree. 
It is widely distributed to the north and northwest, extending into 
Alaska. In the New England States it is not as abundant as the Red 
Spruce and is not used for lumber purposes to the same extent as its 
near relative. 

In the eastern provinces of Canada, where it is prol)a])ly the only Sprnce cut in 
large quantities, it is used in construction and for the interior tinish of buildings and 
for paper pulp. * * * White Spruce lumber is also occasionally -manufactured in 
Dakota and Montana, etc.^ * * * 

The wood of the White Spruce is straw yellow, very light, and not 
strong. Resin passages occur now and then in the very narrow band 
of summer cells. As an ornamental tree it is more extensively used 
than the Red Spruce. 

^Von Schrenk, H., Two Diseases of Red Cedar. Bui. No. 21, U. S. Dept. Agr., 
Div. Veg. Phys. and Path. 
2 Sargent, C. S. Silva of North America. 12:37. 1898. 



17 

BALSAM FIR. 

The Balsam Fir/ Ahies halsamea (L.) Miller, is a tree common all over 
New England, .springing- up wherever the White Pine or Spruce are 
cut away. It produces great quantities of seed, which germinate 
readily the succeeding year. The trees are usually smaller than the 
Spruces, growing to be 50 feet (15 meters) in height and 6 inches to 1 
foot (15 to 30 cm.) in diameter. Its wood is used for a cheap grade of 
lumber, for it is ver^ light and does not have any resisting power. 
In central Maine it is often cut with the Spruce and sent to the pulp 
mills. The trees are very subject to the attacks of insects and fungi. 
The large black ants^ annually destroy hundreds of trees. 

HEMLOCK. 

The Hemlock, Tsuga canadensis (L. ) Carriere, is a stately tree, usually 
60 feet (18 meters) in height, having a trunk 2 to 4 feet (0.6 to 1.2 
meters) in diameter. It is an important element of the northern forest, 
and has long been valued for its l)ark, which is extensivelj^ used in the 
tanning of leather. As an ornamental tree it has few equals among 
our native trees. 

In stately grace it has no rival among the inhabitants of the gardens of the northern 
United States, when, with its long lower branches sweeping the lawn, it rises into a 
great pyramid, dark and somber in winter and light in early summer, with the 
tender yellow tones of its drooping branchlets and vernal foliage.'^ 

It is one of the most valuable trees of the Eastern forests. It is estimated that in 
the year 1887, 1,200,000 tons of bark of this tree were harvested, and although a large 
part of the timber of the trees cut and stripped of their bark is allowed to rot on the 
ground it is believed that the average annual value of the material of all kinds 
obtained from this hemlock is not less than $30,000,000. 

The tree is one which grows ver}^ slowly. The seedlings are very 
sensitive to exposui'e and do not recover I'cadily Avhen inju)-ed. The 
wood is very coarse and ])rittle and is worked with ditKeulty. It is, 
however, used considerably in various localities for a cheap grade of 
lumber, and at times, when other wood is not to be had, for railway 
ties, fence posts, and railing, but its resisting powers to weathering 
inlBluences are very slight. 

ARBOR VITiE. 

The Arbor Vita\ Thuja, occidentalk^ L.,* is a tree found throughout 
the northern parts of New England, pai'ticularly in wet, boggy lands, 
where it forms dense forests, the individual members of which grow 

'Sargent, C. S. Silva of North America. 12:107,108. 18<)S. 
■"Tlopkins, A. I). Preliminary Report on the Jiisect Knemies of the Forests of the 
Northwest. Bui. No. 21, U. S. Dept. Agr., Div. Entomology. 1899. 
•''Sargent, loc. cit. ()(>. 

* Sargent, C. S. Silva of Nortii America. 10: 120. 1896. 
5776— No. 25 2 



18 

to be 50 feet (15 meters) in height, with trunks 6 inches to 1 foot (15 
to 30 cm.) in diameter. The wood is very durable and is on that 
account prized for fence posts and railway ties, for foundation walls, 
and for making shingles. The wood itself is rather coarse, yellow 
brown, and is free from resin ducts. The trees are grown as orna- 
mental trees, particularly in the form of hedges. 

WHITE PINE. 

The White Pine, Pinus 8trohxis L., once so large a factor in the lum- 
ber industry of the New England States, is now comparativeh' rare as 
mature timber. It is subject to a number of diseases which will be 
treated of in a special paper. It is left out of consideration on that 
account in the present report. 

TAMARACK. 

The Larch, or Tamarack, Larix laricina (Du Roi) Koch (Z. ameri- 
cana Michaux),^ is a tall, stateh^ forest tree which is found growing 
with the White Pine and Spruce and in some sections forms extensive 
forests, especially in low swampy lands. It grows throughout the 
Northern States, ranging from Maine westward to the western slopes of 
the Rocky Mountains, and southward to northern Pennsylvania, Indi- 
ana, and Illinois, and to central Minnesota. As an ornamental tree it 
is highly prized because of its graceful habit and thrifty growth. The 
wood of the Tamarack is extensivel}' used in shipbuilding, for railway 
ties, and telegraph poles. It is veiy durable and hard. Compared with 
the AVhite Oak, it has a crushing strength of 1.38. Dudle}'" sa3^s of it: 

The quality of the wood of this tree is such that it deserves to be widely known 
and more extensively used for ties than it has been. * * * The wood is easily 
treated with antisejitics to prevent decay, especially with sulphate or acetate of iron, 
and ties so treated have lasted over thirty years under heavy traffic. 

POIiYPORUS SCHWEINITZII Fr. 

Polyporus schweinitzii Fr., Syst. 1 :351. 
Polyporus schweinitzii Fr. , Epic. 433. 
Boletus sistotremoides Alb. and Schw., 243. 

[Figured in Fries's Icon. Hyni. No. 179.] 
OCCURRENCE. 

This fungus is one which is very common throughout the Northern 
forests on the Spruce and Fir, and, as Dr. Farlow remarks,'' appears 
to be very much more prevalent in this country than in Europe.* It 
certainly stands near the top of the list in point of destructiveness. 

1 Sargent, C. S. Silva of North America. 12:7. 1898. 
^Dudley, P. H. Bui. No. 1, Division of Forestry. Ajjpendix I. 51. 
"Sargent, C. S. Silva of North America. 11:11. 1897. 

''Hartig (Lehrbuch der Pflanzenkrankheiten. 177. 1900) says it occurs only on 
Pines. 



19 

It attacks young trees as well as older ones, entering the tree through 
the root system and growing up into the trunk for sometimes 40 and 
50 feet (12 to 15 meters) from the ground. The mycelium makes the 
wood of the Spruce very brittle. Diseased wood is of a yellowish 
color; it has a cheesy consistency so that it can be cut across the grain 
with a knife quite readily and without much resistance. When dry, 
it is readily powdered. The brilliantly colored. fruiting bodies are to 
be found in July and August growing about the base of the affected 
trees, more rarely on the trunks. (See text fig. 1; also PI. I, fig 1.) It 
was found more frequently in places where the air was laden with 
moisture — for instance, along the coast and near lakes. On many of 
the islands which lie off the Maine coast the fungus was found to be 
very plentiful, even to a distance of 5 miles (8 kilometers) from the 
mainland, showing that the spores must be carried for a considerable 
distance. One small island had some 12 trees on it, all White Spruces, 
of which 7 had old fruiting organs of this fungus growing about the 
bases of the trunks. 

STRUCTURE OF DISEASED WOOD. 

The wood of the Red Spruce or the Fir when first invaded b}^ the 
mycelium turns yellow, and after a time cracks here and there as if 
dried rapidly. A cross section of the trunk of a young Fir, made 
about 6 feet (about 2 meters) above the ground, is shown in PI. II. The 
large crack at the side was made in chopping down the tree; the other 
cracks in the heartwood show plainl}^ how the wood has shrunken. The 
structural changes which take place are as follows: Soon after the myce- 
lium enters the wood of the Spruce the color changes and the wood 
becomes more or less brittle. This is due to the fact that at various 
points in the summer wood cracks appear in the walls of the tracheids 
and extend in the spiral direction around each tracheid. The break 
deepens gradually until it extends entirel}^ through the secondary 
lamella up to the primary lamella. The latter remains unbroken. The 
spiral breaks increase in number and at last the tracheid has the 
appearance shown in PI. IX, fig. 1. There appear to be two series of 
cracks, one extending upward from left to right, the other from right 
to left. This appearance is due to the fact, as Hartig has shown, that 
one sees the breaks in the walls of two tracheids at the same time. 
Hartig mentions that these cracks all extend in a spiral direction, 
none paralh'l to the walls. This is certainly a striking fact, and seems 
to distinguish wood attacked by this fungus from that injured by 
many others. It will be shown that some other fungi, Polyporus sul- 
fureiis and a form of Polyporus destructor possibly, attack the wood of 
the Spruce and the Yellow Pine, respectively, in a similar way. 

The spring wood has few cracks. These aic inaiidy in the 
pits, where four radiating cracks appear in the secondary lamella. 



20 

Wherever a hypha has passed through a wall is to be found the peculiar 
double spiral crack. (PL IX, fig. 1.) 

The diseased wood of the Balsam Fir differs little from similarly 
affected Spruce wood. The summer tracheids as a rule are not so wide 
as those of the Spruce, hence the spiral cracks are not as evident as in 
that tree. They appear to extend more or less parallel with the walls. 
They are likewise present in greater numbers, so that there is very 
little left of the wall. 

Wood which is ir. the last stages of deca}^ is exceedingly brittle. It 
does not partake of the character of brown charcoal as much as does 
Pine wood similarly diseased, but is much firmer. It absorbs water 
very rapidly, and when boiled in water for a few minutes becomes soft 
and putty like and can be kneaded like bread dough. When dry it 
can not be cut with a knife without crumbling, but when soaked in 
water it can be readily cut into the thinnest sections. These have no 
elasticity, however. The walls of the wood cells are very thin and 
swell to several times their size on addition of dilute potash. Here 
and there are found masses of resin, more frequently in the Balsam 
Fir than in the Spruce. As the wood grows older the action of the 
mycelium seems to stop. The wood changes no further except that it 
cracks more or less. It appears to be very resistant to change brought 
about by weathering. 

FRinTING ORGAN. 

The first fruiting bodies observed began to appear toward the begin- 
ning of July. Small rounded masses grew out from the l)ark and very 
soon became flattened horizontally. The specimen shown in the photo- 
graph (fig. 1) was watched closely and measured daily from the time 
of its first appearance until it had reached its full size. By means of 
wires stuck at the edge of the growing shelves, it was easy to measure 
accurately the daily increase in diameter. The hyphaj rapidly grew 
around the wire so that it became embedded in the mass of the sporo- 
phore. One of the wires is visible at the right side of the middle shelf 
of fig. 1. The measurements show that for the first two weeks the 
larger shelves grew about one-fifth of an inch (one-half centimeter) a 
day in all directions; on warm days, however, the increase was more 
than that and on other days not so much. The youngest portion of the 
sporophore was yellow-brown, which in three or four days deepened 
to a red brown. The unequal development of the mass caused concen- 
tric rings to ap[)ear on the top of the pileus, showing b}^ the low ridges 
and shallow furrows, respectively, where any particularh^ rapid growth 
had set in and where it had stopped. On August 15 the growth in 
width suddenly stopped. When full grown, the largest of the three 
shelves was 16 inches (40*"") across at the widest point and 8 to 1-1 
inches (20 to 35*^°^) from front to back. 



21 



The, sporophores grow either on the roots of an affected tree or on 
the trunk, the former being the usual position. When growing on 
the ground the pile us is supported on a ver}' short stalk; it is sessile 
when growing from the trunk. There are usually several shelves 
which are grown together at the center in the ground form, or grown 
one above the other in the trunk form (see text figure 1 and PI. I, 
fig. 1). The whole body varies greatl}" in size. The smallest 
specimens collected during the past summer were 4 inches (lO^"") in 
diameter; the largest about 14 inches (35""^). The hjnnenial layer 
begins to form some three days after the body of the pileus is com- 




Fiu. 1. — Folypuras ncliuxiiiitr.ii Fr. growing on u fallen Fir. 

plete, so that there is always a wide band of sterile h3'phj« on the 
under side of the pileus during the period that the pileus is growing 
in width. When this growth stops, the tubes gradually form close up 
to the edge. The h3'menium when f n^sh is rose colored; when touched 
or bruised it turns dark red very cpiickly. The bright colors of the 
3'oung pileus gi'tiduallv give wa\^ to more su)>dued ones as th(^ fungus 
grows older. A few days after growth has come to a standstill, the 
spores ripen and begin t(^ bi; discharged. T'hey come off in clouds 
plainly visible to the naked eye. Slips of glass placed under the 
pileus and left overnight had so thick a layci- of spores deposited 



22 

on them that it was impossible to perceive anythino- throuo-h the 
glass. Attempts were made to grow the spores in the woods on bread 
cultures. These all failed, however, because of constant interference 
on the part of inquisitive squirrels. 

The spores came off at intervals as if they were being discharged 
by some force acting within the tubes. Pieces of the pileus were 
accordingly turned over in a jar so that the tubes of the hymenium 
pointed up. Glass slips were supported over the tubes overnight, and 
on the following morning a few spores were found on them, but the 
number was so small when compared with the large number discharged 
from a similar piece laid with the pores pointing down, that it did 
not seem probable that there was any very active discharge going on. 
The spores were borne far away from the spot where the^^ fell. Owing 
to their exceedingly small weight, ever}^ disturbance in the air carried 
them ofl'. It was surprising to see how slight a disturbance sufficed. 
The flame of a candle held near the sporophore remained perfectly 
motionless while clouds of spores were swaying to and fro under the 
hymenial layei's. The spores were sown in aqueous decoctions of 
humus, but did not germinate. The facilities for doing more careful 
work were not at hand in the woods, so experiments on the manner of 
germination had to be left for a future time. 

At the time of ripening of the spores it was noticed that hundreds 
of drops of a yellowish liquid were hanging from the hymenial sur- 
faces ever}' morning when the fungus in question was visited. Some 
of these drops were carefully collected and Avere examined. In them 
floated a number of spores and flocculent 3 ellowish brown masses, 
which stained j^ellow with nitric acid. These were present for several 
daj's. Thereafter the liquid was almost clear except for numberless 
spores which were in every drop. For three weeks the drops were 
collected with a pipette during the da}', and during the night a plate, 
carefully protected against dew and rain, was placed under the fun- 
gus. In this way about three-fifths of a pint (300"'') of liquid were 
collected. This was poured into an open dish and put in a cool place, 
where the water was allowed to evaporate. A thick brown sirup was 
left after some weeks, which had the odor of verj^ impure molasses. 
The sirup was transferred to a vial, which was corked and placed in a 
warm place. In a few days delicate needle-shaped cr3^stals shot out, 
which upon examination proved to be melezitose and mycose, sugars 
sometimes found in fungi.* 

At the same time that this secretion appeared on the h^'menium, or 
rather shortly afterwards, a number of small beetles began to devour 
the hymenium with great avidity. So active were they that within 

'The writer is indebted to Dr. O, Lt)e\v for the deterinination of these sugars. 



23 

three weeks of their appearance the hymeniiim was entirely destroyed, 
and of course with it whatever spores had remained. It is suggested 
that the secretion of this sugar and the destruction of the hymenium 
by these beetles may have some meaning in connection with the dis- 
persal of the spores. It is a point worthy of further observations by 
local observers in future years. The rapid destruction of the hyme- 
nium is very marked. It is exceedingly difficult to get perfect speci- 
mens of the sporophores after the end of August. The upper surface, 
which is usually moist, becomes covered with a fine layer of fallen 
spruce needles, and before long a covering of mosses hides the brown 
sporophore completely. It is no unusual occurrence to find these old 
moss-covered sporophores several years after their formation, at the 
base of some old Spruce. 

The basidia and spores have nothing about them which is very dis- 
tinctive. Numerous peculiar hairs project from the hymenium, which 
are surrounded with a film or drop of clear liquid in which numerous 
spores are caught. When viewed by reflected light these glisten like 
dewdrops within the pores. The latter are exceedingly irregular, so 
irregular in fact that one can hardly call them pores. They partake 
more of the nature of pockets, which are divided by many much con- 
voluted walls into various chambers. The pores extend almost to the 
margin of the pileus and are usually about one-eighth of an inch (S™"") 
deep. 

EFFECT OF FUNGUS ON THE TREE. 

The fungus seems to spread through the ground, attacking the tree 
first at its root system, and growing thence up into the trunk. Wher- 
ever one tree is affected, others similarly diseased will usually be found 
close by. Infection may take place through the root on one side of a 
tree. The heartwood of that root will be destroyed and then the wood 
of the portion of the trunk nearest that root becomes affected. Many 
trees were cut down where but one-half of the trunk had been rotted 
by th<» fungus, and oftentimes only a small spot was visible where the 
fungus had just begun to grow. The tree continues to stand until 
either the roots or the trunk become weakened to such an extent that 
they can no longer hold the tree erect, and then the first wind storm 
overturns it. Fig. 1 shows a large Fir, the root system of which was 
almost entirely destroyed. In its fall the lower part of the trunk split, 
revealing decayed wood to a distance of 12 feet (al)()ut 3f meters). The 
tree was probably blown over in the spring of 1S!>!», and in the follow- 
ing July the sporophores formed on the trunk. A large tree thus dis- 
eased is a constant source of danger to all others about it. Not only 
may the disease be comnuuiicated to them, l)ut in its fall such a tree 
breaks down many a small tree, not to speak of the large numbers of 
very small second growth which it destroys. The sporophores form 



24 

on fallen trees for several years in succession, possibly omitting a j^ear 
now and then. As a rule but one set of sporophores is found on one 
tree. As has already been said, young trees are subject to the attacks 
of this fungus as well as older ones, although the latter are probably 
more so, because the points of infection are so much more numerous. 
Nothing is known as yet of the manner in which the fungus enters 
the tree, nor of the rate at which it grows within a tree after having 
obtained a foothold. 

TREES ATTACKED. 

Polyporus schweinitzii was found growing on the roots of the White 
and Red Spruces, Balsam Fir, and Arbor Vitce. It is likewise com- 
mon on the White Pine {Pinus strohus). 

METHODS OF COMBATING THIS FUNGUS. 

Because of its destructiveness Polyporus schweinitzii is perhaps the 
most to be feared, where living trees are concerned. As it spreads 
through the soil it is difficult to detect, and still more difficult to com- 
bat. In the European forests a deep trench is dug around an infected 
tree or group of trees; this trench prevents the spread of the mycelium 
through the ground to neighboring trees. Such a method can not be 
recommended for American forest tree conditions, at least not for the 
present. If a group of infected trees is met wnth in the forest while 
lumbering it may prove advantageous to cut all trees in the vicinity of 
the diseased ones. Some of these may produce a hollow sound when 
hit near the base, an indication that the decay has started. It may not 
have gone up into the tree very far as yet, so that one or more logs 
can be obtained from the top. It will not be profitable to hunt out 
diseased trees as is done in European forests. There is as j^et no 
evidence that the fungus can infect a tree above ground, consequently 
it need not be feared in burned-over regions, or such as have been 
attacked by bark beetles. 

POIiYPORUS PINICOIiA (Swartz) Fr. 

OCCURRENCE. 

This fungus occurs widely distributed over the world, growing on 
conifers and occasionall}^ on Birches and other deciduous trees. In 
the New England forests it is one of the most frequent fungi found 
on living or more often on dead trees of Spruce, Pine, Fir, and Hem- 
lock. From three to ten of its bright colored sporophores may grow 
on a single log for several, varying from three to five, years. At the 
end of that time the mycelium has used up the available food supply 
in the loo' and dies. 

The sporophores grow on living trees, but these alwa5's appear 
weakened or sickly. No vigorous, healthy trees were found on which 
this fungus flourished. It is essentialh^ a wound parasite, entering 



25 

the trunks and branches above ground. Old knot holes or branch 
wounds, wounds produced by fire, or wounds made by animals, are 
favorable spots for the entrance of the spores. Wherever a tree 
dies from any cause this fungus is sure to attack it before long. In 
the sections where the bark beetles had been active some years ago 
there were many trees the wood of which had been destroyed by this 
Polyporus. 

The large holes made by woodpeckers offer excellent opportunities 
for the entrance of spores. As the woodpeckers are very active in 
exterminating insects inha])iting the bark (presumably the bark beetles 
among others), we have here a case of their allowing one enemy to 
enter while destroying another. In old windfalls the dead trees were 
covered with sporophores, some of them many years old, showing that 
these trees had become infected very soon after the trees had been 
blown over. This fact is of importance, as it suggests that these trees 
could be saved by the lumberman if carried to the mills shortly after 
their downfall. This will be referred to again. Plate IV is from a 
photograph of a portion of a Spruce trunk. The small white spots in 
the bark are holes of a borer filled with the mycelium of the fungus. 

STRUCTURE OF DISEASED WOOD. 

Wood of the Spruce in which the m^'celium of this Polyporus has 
been growing for some time deserves the description "entirely rotted" 
par excellence. The wood has been changed to a 1)rittle red-brown 
mass, which has cracked in many directions. The individual pieces 
are barely held together by countless sheets of mycelium which have 
filled the spaces resulting from the cracking of the wood and form an 
intricate network of larger and smaller sheets. In PI. IV a portion 
of a log in the last stages of decay is shown. At one side a sporo- 
phorc one year old and another just beginning are visible. The sap- 
wood has mimerous tunnels of a borer filled with remnants of the 
borings. Such wood has lost all strength, and falls to pieces at the 
slightest touch. If the mycelium attacks a standing tree the decay 
goes on within it until the trunk becomes so weak that an ordinary 
wind blows it over. The shrinkage which takes place in the wood as 
it is being metamorphosed is very considerable, as is evidenced by 
the large number of wide cracks which fill it, passing both across the 
annual rings and parallel to them. 

The changes which result in the wood may be descril)ed as follows: 
In a tnra just attacked the wood a))out the point of entrance of the fun- 
gus turns darker jind finally becomes a decided red-bi'own. Before k)ng 
small whitish areas appear here and there scatt(n-ed irregularly through 
the wood. Some of these are mere lines, while others form white 
patches circular in shape, surrounding small areas of wood about the 
size of a pinhcMid, which are red-brown (PI. III). Others again have 



26 

the .shape of broad, irregular liancls. which extend across the rings of 
growth. The point.s at which these white areas appear and the direc- 
tion which they take do not seem to be controlled by any particular 
factor, for they are exceedingl}^ irregular. The areas are shown in 
PI. Ill, which represents a radial view of a spruce log in the earlj^ 
stages of attack ])y the mycelium. The very fine white lines which 
are visible near the center of the log, extending across the annual 
rings, are of a different character from the white areas spoken of. It 
will be noted that in the white areas the parallel lines which indicate 
the summer wood are ver}' distinct. A microscopic examination of a 
white area shows that at this point the cells of the wood are com- 
pletely filled with fine hypha\ which form a dense mass within that 
area. Mixed in with the mycelium are the granules of an amorphous 
substance, readily soluble in alcohol, which is evidently resin. This, 
together with the mycelium, gives the white appearance to the spots. 
As the summer tracheids have a very small lumen, they have compara- 
tively little mycelium, which accounts for their being visible as lines 
extending through the areas. The size of an ai'ea is thus dependent 
upon the distance to which the mycelium has grown, and probably 
varies from time to time. It is suggested that the smaller areas are 
also the ones most recentl}' invaded. At this stage of the decomposi- 
tion the mass of the wood is already very brittle. Here and there 
cracks have appeared in the walls of the wood cells wherever a hypha 
has passed through them. Some tracheids appear like sieves because 
of the numerous holes. The changes subsequent to this stage of 
decomposition consist essentially in a carbonizing of the wood and the 
formation of the sheets of mycelium. The former change is one proba- 
bly induced by some ferment, the nature of which it is the intention to 
discuss more fulh' in another report. The cells of the wood gradually 
show more and more cracks and fissures, and the diameter of the walls 
decreases about half. The main shrinkage takes place in the secondarj" 
lamella^. The fissures which appear in the spring wood usually 
emanate from the holes formed by hypha?. The outline of these holes 
is irregular, but approaches a circle in form. In the secondary wall a 
fissure is soon formed which extends diagonally from left to right 
across the cell. Viewed from the top there are apparently two 
fissures, but these can readily be shown to belong to the secondary 
lamella? of adjoining cells. The fissures never extend into the primary 
lamella?. Various stages of such fissures are shown at PI. X, fig. 4. 
In the bordered pits at first two and later four fissures are visible in 
the secondary ring, which, as Hartig has surmised,^ are probably 
brought about b}' drving. Here and there (PI. X, fig. -I, c) a hypha 
has passed directh' through a bordered pit and in its passage has 

^ Hartig, Robert. Zersetzungserscheinungen des Holzes, etc. 



27 

dissolved more or less of the iiie]n])rancs. In the summer tracheids 
the iuim])er of fissures in the walls is ver^^ larg-e. They all extend 
diagonally across the tracheids as in the spring- cells, and wherever a 
hole occurs there two fissures seem to cross. The smaller fissures 
have no counterpai't in the secondary lamella of neighboring cells as 
a rule, showing the complete independence of the two halves of the 
cell wall. The margins of the fissures are ragged, and the fissures 
themselves are very irregular in shape, and look as if they had been 
formed suddenly. The wood substance itself has been changed com- 
pletely. With phloroglucin and hydrochloric acid it stains red, and 
when the wood, finel}" powdered, is extracted with absolute alcohol 
quantities of hadromal are obtained. No reaction for cellulose can be 
obtained, and it seems as if the latter has been completely destroyed. 
An aqueous solution yields several compounds — an amorphous sub- 
stance, possibly a humus compound; a faint trace of some sugar, as 
shown by the phenylhydrazine test; and small quantities of citric and 
succinic acids. These are doubtless all decomposition products. 
There is also some compound present which reduces Fehling's solu- 
tion vigorously. After the walls of the tracheids are filled with holes 
and fissures they have reached the last stage of decomposition. A 
touch will then cause them to fall into many pieces. When boiled in 
water, the walls swell somewhat, and a pasty mass results when 
squeezed. With dilute KOH the walls swell to three times their size, 
and portions of them dissolve completely. 

The formation of the sheets of mycelium seems to take place in one 
of two ways. In one case the hyphaj in the white areas mentioned 
above exert a solvent action on the walls. This first becomes evident 
in the cells of the medullary rays. Their walls disappear completely, 
and the spaces are rapidly filled by the growing mycelium. The walls 
of the wood cells adjoining the medullary ra3^s are attacked, possibly 
at the same time. The secondar}^ lamella* shrink and finally disappear 
altogether, leaving a fine framework of the primary lamella. This 
framework is usually broken in hundreds of places, and as a result 
only pieces of the walls remain em])edded in a web of h3'pha?. The 
})ordered pits are destroyed from within outward, the torus resisting 
longest (PI. X, fig. 5). The latter is often freed and can be seen lying 
free in the cell. The triangular areas (as seen in cross section) of the 
primary lamella, formed where several cells join, are the last to dis- 
appear. A hole is thus formed which is completely filled with myce- 
lium. The latter spreads from this point in several directions. The 
writer is of the opinion that very little actual solution of the wood 
takes place, resulting in the fornuition of holes or cavities. Hero and 
there it doul)tless does occur, but rather as the exception, and possibly 
in the early stages of the development of the mycelium. It seems 
very much more prol)ab1(* that the socond mode is the usual o!ie. As 



28 



the m^'celium spreads through the wood it brings about the chem- 
ical changes spoken of, extracting substances from the walls. This 
reduces the volume of the wood and causes the fissures in the cells. 
But before long the shrinkage becomes so great that larger masses of 
the wood suddenly break away from each other at many points 
throughout the wood. Many small fissures are thus formed, which 
extend in every direction, both across the rings and within them in a 
tangential direction. The fissures are very irregular. Sometimes 
the}" extend for a short distance within one ring, then cross over into 

another, and so on. They ap- 
pear both in the spring and sum- 
mer wood, and not infrequently 
start in one ring and extend 
radially through the summer 
wood of that ring into the 
spring wood of the next. Often 
the breaks follow the lines of 
the medullary rays, but just as 
often they do not (PI. X, fig. 1). 
The process is evidently one of 
drying, for the same result is 
seen when wood dries, resulting 
in the formation of fissures, the 
so-called ''checking" of wood. 
If the fissures are near points 
where mj^celium of the fungus 
flourishes, the latter grows into 
the spaces and fills them com- 
pletely. Several fissures may 
join, forming an irregular longer 
^ one. In PI. X, fig. 1, a sketch 











^p?(fi- 




aOoc 






gaSf 



^^OQ 



O 





inr\ 



Fig. 2.— Cross section of Spruce wood showing masses 
of mycelium of Poli/porus pinicola (Swartz) Fr. 



is shown of the cross section of 
several annual rings, showing 
how and where the breaks have 
formed. As the wood dries 
more and more the fissures widen and the mycelium keeps step with 
them. In small fissures it is very evident that the fissure has formed 
as a break and not by the solvent action of the mycelium. Fig. 2 
shows such a fissure filled with mycelium. (The same figure is shown 
at c, PI. X, fig. 1.) A glance at the rows of wood cells will show how 
they have been forced apart, breaking one row. The rows are inclined 
toward one another, as one would expect them to be. The figure also 
shows a medullary ray at the right, the walls of which have disappeared. 
In the cells surrounding the break the mycelium flourishes, and here 
and there some of the walls are destroyed, making a small hole. 



29 

In the last stages of decay the fissures are very numerous, each filled 
with a solid felt of white rayceliuui. The felts extending in radial 
lines join those extending- in tangential lines here and there, and they 
hold in place the wood which would otherwise have fallen to pieces 
long before. In a live tree the heartwood is attacked first, and grad- 
ually the decay spreads to the sapwood. In the latter the browning 
of the wood is more marked, owing to its lighter color. Nothing 
positive can be stated at present as to the rapidity with which the 
decay brought about by this fungus proceeds. It appears to be very 
rapid, for trees l>lown down some two years before were found in an 
advanced stage of decomposition, with sporophores forming on their 
trunks at various places. 

FRUITING ORGAN. 

The sporophores of this fungus are very large and conspicuous, and 
are formed on logs during spring and summer, often many together on 
the same log. The form of the pileus is exceedingly variable (PL V). 
It is entirely resupinate when growing on the lower side of an over- 
turned log (PI. IX, fig. 6). In such a case there is no upper surface 
for several years. After three or four years the edge extends out 
beyond the curved surface of the log, and a narrow surface is exposed. 
Usually the pileus forms a distinct bracket on the side of a standing- 
trunk or log. This bracket is sometimes hoof-shaped, then again very 
much extended. In size it varies from an inch to a foot (2.5 to SO""") 
in width, or even more in extreme cases. The average specimen is 4 
to 6 inches (10 to 15°'") wide. The upper surface of the bracket slopes 
toward the margin, and is divided into a number of regular divisions 
or lobes, which corresjDond evidently to periods of growth (PI. V). 
The lobes are smooth and dark red-brown when old. The youngest lobe 
is bright red, shading into a pale yellow at the very edge of the pileus. 
In many specimens the upper surface is almost black, and some of the 
lobes shine as if varnished. The number of lobes varies with the age of 
the specimen; one of the oldest found had fourteen. It has not been 
determined whether these lobes represent annual increments of growth, 
so it is not possible to say how old any of these large sporophores may 
be. The mass of the pileus is extremely hard and woody, and shows 
division into a number of zones (PI. IX, figs. 5, 6, 7), which are always 
greater in numljer than the lobes showing at the top. The hymeniuni 
is a pale yellow, very smooth, and assumes a watery appearance when 
bruised. It is very rarely perfect, as many insects are constantly at 
work eating away the tissue. The outer edge of the lower surface of 
the pileus is raised, forming a distinct ridge. At the inner edge of 
this ridge the formation of the tubes of the hymeniuni begins. This 
ridirc is continuous around the whole lower surface and forms a char- 
acter which is very constant. In young individuals it is wider than 



30 

in older ones. It is composed of looseh' interwoven hyphse, which 
form a continuation of the main hyphal strands which compose the 
body of the pileus. The hyphse of the latter start from a central 
point on the bark and radiate out in several directions (PL IX, fig. 7), 
forming- a mesh which at first is very loose. The hyphai are almost 
colorless and have a decided lumen. As they grow older their walls 
become brown and very thick, so that the lumen is reduced to a very, 
small one. The peripheral growth of the hyphaj takes place in such 
a way as to form well-defined la^^ers. For .several years these laj^ers 
are added one outside of the other. The lowermost portion of each 
laj'er is usually less dense than the outer portion, and after the hyphse 
turn brown large masses of crystals of calcium oxalate are deposited 
in the meshes of the outer portion. The alternation of layers of less 
density with those of greater densit}" makes a differentiation of laj'ers 
possible. The laj^ers vary considerably in width (PI. IX, figs. 5-7), 
and it is suggested that this is probably due to varying conditions; 
probably the amount of food supplied and the amount of available 
moisture exert a marked influence. The pileus grows in width and 
length by the direct elongation of the hyphie of the last layer. After 
several 3'ears' growth the hypha- on the under side of the developing 
shelf grow down in a vertical direction and give rise to the pores. 

The pores. are ver}^ long and are continuous from year to year. 
After a time the}^ become plugged at the l)ottom by hj-ph^e which 
grow into them from all sides. Different sporophores differ in this 
respect. With some the pores are open through eight or ten of the 
recent layers; in others the growth of hyphai is so vigorous that the 
pores are closed almost as rapidly as they are formed. The h^^menium 
arises on the surfaces of the pores from hyphte of the trama which 
turn at right angles to the general direction of the tramal hyphse. 
The latter have very thick walls (PL IX, fig. 12) and extend longitudi- 
nally, forming a very loose network. The tips of those hypha? which 
form the hymenial laver are thin walled. The hymenial layer itself 
is composed of hyphre of almost equal width. The layer is a very 
narrow one. Cystidia are practically alisent. The basidia barely 
rise above the general surface and do not differ materially in form 
from the paraphyses. The four spores are colorless. Amid the 
tramal and hymenial hyphfe accumulations of calcium oxalate crystals, 
colored red-brown, occur in great numbers, likewise large quantities 
of an oil readil}' soluble in ether and becoming solid at about 59" F. 
(15'^ C). The growth of the hymenial la^^er is very irregular. At 
one and the same time pores ma}' be forming on one side, while at the 
opposite side the old pores are completely plugged. The h3'menium 
renews itself at frequent intervals. The vitality of its hyphsB is very 
great, for it is not at all rare that insects eat away a considerable por- 
tion of the lower side of the pileus. These parts die and turn brown. 



31 

The remaining- portions then form separate centers of growth, which 
gradual!}' spread over the dead portion and unite, after several years 
perhaps, completely covering the dead part. A view of such a pileus 
is shown on PI. IX, fig. 4; several areas have already joined, forming 
a larger one, and a number of small centers are evident. 

The spores begin to be discharged in July. Growth of the lower 
side of the pileus takes place at the same time. Black cloths were 
pinned to the under side in June and by the end of August large por- 
tions of them were found completely overgrown with hypha?, and 
pores were beginning to form on the under side of the cloth. While 
the growing season lasts drops of a glistening yellow liquid are con- 
stantly being discharged from the hymenium. It is of interest to note 
here that the secretion of these drops was noticed b}^ Fries in a 
description of this fungus.^ Several cubic centimeters of these were 
collected and were found to hold in solution melezitose, the same 
sugar discharged from the sporophores of Polyporus schweinitzii. As 
insects, particularly small boring beetles, eat the hymenium with 
great avidit}^, it is possible that the sugar ma}^ serve to attract these 
insects to the sporophores, causing them to carry the spores to unin- 
fected trees. 

TRAMETES PINI (Brot.) Fr. forma ABIETIS Karst. 

Pobjporus jjiceinus Peck. 
Pohjpoi'us abielis Karsten. 

OCCURBENCE. 

This fungus is very common in the forests of the New England 
States, and occurs northward into Canada and Newfoundland. The 
writer found it conmion oh the Spruces and Firs in the Adirondack 
forests. It grows on nearly all the conifers and has been found by the 
Writer on the White Pine {Pimis strohus), the Red Spruce {Plcea 
ruhens), the White Spruce {Plcea ccmadensls)^ the Hemlock {Tsuga 
canadensis)^ the Larch, or Tamarack {Larix larichia), and the Fir 
{Abies halsamea). It attacks living trees after they have reached such 
a size that they form heartwood, and honeycombs the wood in such a 
way that it appears filled with small holes, many of which are coated 
with a shining white lining. The changes which are brought about in 
the wood are difi'erent somewhat for the ditt'erent kinds of trees and will 
be described separatelv. Of the six trees the Tamarack seems to be 
the most readih' attacked. A greater per cent of the older trees of 
this species were fecund affected than of the other five. The Spruces 
came next, and the Balsam Fir last. 

The fungus enters the trees through the stubs of broken branches 

> Friea, Eliaa. Epicrisis Syst. Myc. 468. 1836-1838. 



82 

and through wounds. The ni^x-clium tlourishes in both hcartwood 
and sapwood of the Spruces, the Fir, and Tamarack, and is confined to 
the heartwood in the Pine. It grows up and down the trunk from 
the point of infection, reaching into the root system and extending 
into the larger branches of the top. Affected trees may remain 
standing in the forest for many years until some more violent storm 
breaks the trunk at a weak point. The wood of the trunk is never 
destroyed completely, as in the case of the two fungi described above. 
In the most advanced stages of decaj^ some fibers of unchanged wood 
are to be found. The extent of their presence varies with the tree. 

DESTRUCTION OF SPRUCE AVOOD. 

The first effect noticed when the mj^celium grows in the wood of 
either of the Spruces is a change in color from the light straw yellow 
of the normal wood to a light purplish gray closely approaching the 
color indicated on the Milton Bradley Color Scale as Neutral Gray No. 1. 
Ver}^ soon this gray deepens to a red brown, the gray remaining as an 
outer ring surrounding the portions of red-brown wood. Small black 
lines appear scattered here and there through the red wood. These lines 
are present throughout an annual ring and extend longitudinally in the 
direction of the wood fibers for a distance of ^V to ^V of an inch (0.5 to 1 
millimeter). Gradualh^ the black lines disappear and here and there 
small white areas appear (Fl. VI, tig. 1). The central portion of each 
area is absorbed and small holes are formed, which have white linings 
of loose fibers. The holes are at some distance from one another and 
are generally arranged in rows corresponding to the annual rings. 
Where the latter are very wide there may be a row of holes in each ring. 
The holes generalh' have their centers within the summer wood of the 
annual ring, but as they increase in size portions of the spring wood 
of that particular ring, as well as the spring wood of the following- 
ring, are included. The holes have a more or less spherical shape, 
which soon changes to a more or less elongated form, the greatest 
diameter extending radially. Fl. X, fig. 2, shows a cross section of 
a piece of wood at an early stage of the destruction. Some of the 
holes at this period are filled with a mass of white fibers, so that there is 
practicall}' no hole. The outlines shown in fig. 2 of Fl. X represent 
the outer limiting line of the white fibers, and the dotted lines (where 
present) indicate where the actual cavity begins. As the growth of 
the mycelium progresses, the holes increase in size and their walls 
approach one another until only a narrow lamella is left (Fl. X, fig. 3). 

A large number of holes appear between the original ones, and in 
the final stages there is practically no wood left except the narrow 
walls separating two holes (Fl. X, fig. 3, and Fl. VI, fig. 2). Adjoin- 
ing cavities rarely, if ever, unite to form a larger one in a lateral 
direction. They often unite at their upper and lower ends, forming 



33 

a long-er hole. The holes are never sharply defined, for there is always 
more or less of a white mass of metamorphosed fibers which remain 
in position next to the unchanged wood, and in many cases the whole 
area is thus occupied, and one can recognize the change only by the 
white color. In older holes this lining- is often replaced by felts of 
brown mycelium (PI. X, fig. 3) which partially or completely fill the 
cavity. The lameihe of wood between the holes ultimatel}^ become 
of an ahnost uniform thickness (PI. X, fig. 3), and on cross section 
show one or more black lines which extend completely around each 
cavity at an equal distance from the walls of two adjoining cavities. 
These black lines begin to appear at a stage intermediate ])etween that 
shown in fig. 2 and fig. 3 of PI. X. They are of variable width and 
grow darker and more marked as the decomposition advances. A lon- 
gitudinal section shows that they extend around the holes in a vertical 
direction also; in other words, a thin hwer of dark-brown matter sur- 
rounds the individual cavities. A closer examination shows that the 
brown lines are due to masses of dark-brown hvpha3 which fill each 
separate wood cell so completely as to plug it entirely. The hyphte 
are closely matted together and are incrusted with a brown substance 
which dissolves in part in dilute KOH and entirely in warm nitric 
acid. These hyphal plugs occur in every tracheid surrounding a hole 
and fill it for a shorter or longer distance. The plugs of adjacent cells 
may be continuous, or may follow one another much as a series of 
steps. This is shown in PI. IX, figs. 10 and 13. The latter represents 
a radial view of a number of tracheids at one side of a hole. The parts 
of the tracheids toward the hole (t) are completely changed to white 
cellulose fibers, while the parts on the other side of the plug (l) give 
lignin reaction. The brown hypha? fill the wood between the holes 
rather loosely, and it is only when about half way between two cavi- 
ties that they become matted together so as to form the plugs. The 
brown incrusting substances occur in or on the cell walls in the imme- 
diate neigh))orhood of the holes, and the manner of occurrence leads 
one to suspect that they were deposited in liquid form, for they have 
difiused through the various cells in all directions from the wall of the 
cavities. 

The changes in the cell walls which result when the mycelium 
attacks them are practically those so fully described l)y Hartig.^ 
There is a gradual extraction of those elements which give the 
so-called lignin reaction, the hadromal of Czapek. This begins in the 
tertiary lamella tuid proceeds outward slowly through the secondary 
lamella. The primary lamella at this period splits in the middle and 
is shortly after dissolved, leaving the individual tracheids entirely free 
from one another, each composed of approximately pure cellulose. 

' Ilartijr, Robert. Zersetzungsersclieinungen des Holzes, etc. 32. 
577«j— No. 2.5 3 



34 

The parts of the primar}^ lamella which are situated between three or 
more cells resist longest (PI. IX. fig. d,j)) and can be found free between 
the white cellulose fibers. The change to cellulose apparently takes 
place simultaneously over a considerable area. The first evidence of 
this change is to be seen in the white spots which come after the black 
lines. The white spots are the points at which the change to cellulose 
has taken place. The cellulose fibers are absorbed later on, giving rise 
to the holes already mentioned. Preceding the change from wood 
fiber to cellulose the wood is full of hj^phae, which become massed in 
centers here and there and bring about the dissolution of the wood. 
It is as yet undetermined what causes influence this local initiation of 
the changes, wdiich is characteristic of several other wood-destroying 
fungi. The growth in size of the white spots or cavities takes place 
rapidly. The hyphffi grow out in all directions from the original 
center, and as they do so the products of decomposition pass outward 
likewise, passing along the tracheids faster than across them. After 
a period the advancing hyphal masses of two adjacent holes meet in 
the narrow lamella of unchanged Avood between the two. A quan- 
tity of brown substance, representing decomposition products, has by 
this time accumulated. It fills the tracheids and coats the hj^phje so 
that these turn very dark, almost ])lack. Warm nitric' acid removes 
these substances entirely, leaving the hypha' and wood almost color- 
less. It is the opinion of the writer that this accumulation of the 
products of decomposition ma}^ account for the fact that the destruc- 
tion of the wood stops at this point, thus preventing the total 
destruction of the wood substance. That this can not be true in all 
cases is shown by the fact that many of the cavities join in the direc- 
tion of the fibers, but in this instance it is probable that diffusion takes 
place to more remote places. The mass of cellulose within the affected 
areas consists of free fibers Avhich remain in place for a period and are 
then gradually dissolved here and there, leaving an actual hole with a 
lining of white fibers. 

In the newly invaded parts of a trunk the mycelium is colorless and 
fills the tracheids completely. The Individual hypha- are somewhat 
thick-walled and have numerous short branches which penetrate the 
cell walls in all directions, leaving the characteristic figure 8 holes 
described by Hartig and others. 

Here and there a second form of decomposition occurs in which 
there is no reduction to cellulose. The process, as found in the spruce, 
is essentially the same as described by Hartig. The secondary 
lamella? arc gradually absorbed, leaving the primary lamella intact. 
The wood araduallv changes into a mass of red-brown fibers which fall 
apart at the slightest touch. 

The destruction of the wood takes place throughout the trunk, 
including the heart and sapwood, and finally even the bark (see PI. 



35 

VI). A trunk like that from which the log shown in PI. VI. fig. 2, 
was taken decays no further, and ma}" stand in the forest for man}^ 
years. After a tree has once fallen the destruction seems to stop. 
Two trees under observation for more than a N^ear did not change at 
all. In both the decomposition had reached, in 1898, the stage shown 
in fig. 2, PL VI, and in September, 1899, no further change could be 
detected. Further observations in this connection are desirable. 
This point is perhaps not as important from the standpoint of the for- 
ester as the power of the fungus to form fruiting organs after the fall 
of a tree, and this assuredly takes place with this fungus for several 
years, as will be mentioned. 

DESTRUCTION OF FIR WOOD. 

The destruction of the wood of Balsam Fir, Ahies hahaniea^ does 
not differ materially from that of the Spruce. White spots appear in 
newly attacked wood, which soon grow into larger ones; the black 
lines surround the individual holes sooner or later and then the decay 
ceases. On PI. VII a radial view is shown of a log taken from a Fir 
which had been blown down during the past summer. 

DESTRUCTION OF TAMARACK WOOD. 

The process of destruction is very different in the Tamarack. This 
is proba))ly due to the different nature of the wood of this tree, which 
seems to be far less resistant than the others. In the Tamarack the decay 
goes much beyond that described for the Spruce and Fir. In the 
early stages (PI. VIII, fig. 1) small white spots appear, which usually 
occupy the entire width of an annual ring. Two or more of these 
spots soon join, at first in a longitudinal direction, then laterally also. 
In that way it happens that very early in the process of destruction 
long stretches of one or more rings of wood are transformed to cellu- 
lose. This is well shown in fig. 1 of PI. VIII. This brings about the 
separation of one or more rings from the adjoining ones, forming in 
that way a series of tangential plates which can readily be separated. 
In the figure each one of the plates visible at the upper end represents 
one amuial ring. The line of separation between the rings is always 
at the point where the summer wood stops and the spring wood of the 
following year })egins. As the decay continues, more and more of the 
sound wood fibers are attacked, leaving loose cellulose fibers. When 
most of the wood has disappeared, black lines similar to those 
described for the Spruce appear, but as there are no such centers of 
decay as in that tree the lines are scattered irregularly. It would 
seem as if there were few decomposition products formed in the Tam- 
arack, and then only at a very late date. Ultimately the tangential 
plates become extremely thin; they are then c<)nii)osed of the more 
resistant sunnner wood cells of this or that wood ring, which ar(> more 
or less infiltrated with resin. The whole body of the former wood is 



36 

a mass of separate fibers, which can be pulled out individualh'. This 
can be seen at the ends of the piece of wood shown in lig. 2 of PI. 
VIII. 

FKUITING ORGAN. 

The fruiting^ or^an of this fundus is exceeding-ly common on all the 
affected trees and has been collected in Maine, New Hampshire, Ver- 
mont, in the Adirondack forests of New York, and in the forests of 
Toronto, Quebec, and New Brunswick. It is readily distinguished 
from allied forms by the light red- brown color of the hy menial sur- 
face, the regular small round pores, and characters of the hj'menial 
layer shortly to be described. 

The form of the pileus A'aries exceedingly and is almost a distinct 
one for every host plant. Hartig, in describing what evidently cor- 
responds to this fungus, ascribes the difference in form of the pileus 
and position on the trees to the different amounts of resin or turpen- 
tine which the wood of the different trees contains. Trametoi ijini^ 
according to him, forms brackets around the stump of dead branches 
in the Pine, the Spruce, and the Larch, while on the Fir the sporo- 
phores may appear at any point on the bark. This is true only to a 
certain extent for the trees of the Northern woods. Travietes pini is a 
very common fungus on nearly all the pines so far seen, and on these 
trees it alwaj's forms very large brackets, which grow, as Hartig says, 
from old branches. On the Spruce, the Fir, and the Tamarack this does 
not hold, for on all three of these trees the sporophores form at the 
ends of old branch stubs and at scattered points on the bark. The 
resin content of the Spruce is somewhat higher than that of either 
Tamarack or Fir, and on that account, possibly, the sporophores are 
more common at the ends of branches. In PI. XII a number of the 
forms as the}^ are found on the White and Red Spruces are shown. 
The bark of these trees consists of corky scales which are constantly 
being peeled off by newer ones developing beneath. The mycelium 
of the fungus, after having penetrated through the sapwood of an 
affected tree, grows rapidly into the 3'ounger parts of the bark and 
ultimately appears as small cushions under several of the bark scales. 
These cushions arc bright red-brown and have a velvety margin com- 
posed of thick-walled hyphtv. which rapidly spread out over the adjoin- 
ing scales, forming a flat sheet (tig. 4). While' the growth in a lateral 
direction is going on, and when the flat sporophore is scarcely one- 
sixteenth of an inch (about 1.5™"') in width, some of the central hyphse 
elongate, leaving small pockets Ijetween them which form the pores 
of the hymenium. The lateral growth may go on for several years, 
while at the same time a downward growth of the hyphse which form 
the walls of the pores brings about an increase in thickness. It ought 
to be said that this tvpe of spoi'ophore was found only on the under 
sides of fallen logs or branches. When the sporophores form on a 



37 

living standing tree they take the form of extended sheets on the 
lower side of the uppermost branches or form as sessile brackets of 
varied shape around old stubs of branches or again as sessile 
brackets at scattered points on the side of the main trunk. Fig. 3 
shows a sporophore growing on the under side of a branch. In such 
a case the mycelium grows out through the bark, forming a long vel- 
vety cushion oftentimes several feet in length. This cushion rapidly 
grows laterally, and on its lower surface the pores arise. The growth 
of such a sporophore may go on for many years. The under side of the 
branch shown on PI. XII, iig. 3 was covered for a distance of 10 feet 
with the brown sporophore. As the latter increases in width it sooner 
or later develops a free upper surface where the body of the sporo- 
phore projects beyond the curved surface of the branch. The cracks 
appearing in the wood are due to drying. Fig. shows the sporo- 
phore as it occurs on the vertical trunk of a living tree. Here a form 
results which approaches most closely to Trametes ])ini (Brot.) Fr. 
The mycelium growls out from between the bark scales, forming a 
small knol) or sometimes several beside or above one another. On the 
lower side the pores soon appear as shallow pits, which are increased 
in depth by downward growth of the hyph^ forming their walls. The 
upper surface of the cushions becomes brown and, because of alter- 
nate periods of growth and rest, concentric lines arise which are more 
or less obscured by the hairiness of the surface. In forms of this 
kind the directive influence of geotropic forces on the position of the 
pores is very marked. The pores alwa3^s extend vertically, and on 
that account when found on a perfectly horizontal surface their open- 
ings are almost round. As one passes on into the oblique portion of 
the lower surface the openings become more irregular and the lower end 
portions of the tubes are exposed until they appear as hollow grooves. 
Where for any reason the position of the trunk or branch upon which 
a sporophore grows is changed, the direction of the pores changes like- 
wise, and instances of this kind are very common. 

On old Spruces ends of broken branches are points where the l)rown 
sporophores of this fungus may be found almost without exception. 
Two cases of this kind are shown on PI. XII, figs. 5 and 7. The Spruce 
loses many of its bran(^hes during windstorms, far more so than the 
Fir or Tamarack. The })utt end of a broken branch keeps on growing 
after the death of the outer portion, and in that way large knobs are 
foiined which may in time cover the wound entirely. It is an exceed- 
ingly slow process, however, and where, as is frequently the cas(\ the 
branch ))reaks off jit a distance of a foot or more, as shown on PI. XII, 
fig. 5, it rarely if ever heals over.' Such branches form the places 

' There ia apparently in the Spruces little of that most efficient natural pruning 
which takes place in the Pines, where a dead branch breaks off very close to the 
trunk. 



38 

where the spores of this fungus find a most suitable place for entrance 
into the trunk. The spore germinates and the m3'celium grows down 
through the dead heartwood of the branch. From there it spreads 
through the heartwood of the trunk, growing both up and down. The 
growth in these directions takes place more rapidly than the lateral 
growth. When the sapwood is reached, the progress is a slow one, 
owing to the resinous contents. At about this time the sporophore 
begins to form. The wood of the callus and the living sapwood of the 
knob become so thoroughly impregnated with turpentine that the 
mycelium does not grow in them, but grows out through the dead 
wood of the branch. At the first point where the hyphse can reach 
the air without haA'ing to go through the collar of sapwood they 
emero-e. Where the dead branch has broken off close to the callus the 
hj'pha? grow out from the stub and form a cushion on it. More 
frequently, however, the red-brown cushion is formed at the point where 
the living callus touches the dead wood (PI. XII, fig. 6). The cushion 
is at first very small and looks as if covered with velvet. The hyphse 
rapidly grow radially and form a sheet which adjusts itself to the 
shape of the callus and branch. At the edges this sheet projects from 
the bark and forms an irregular shelf, the top of which after a time 
becomes zonate and brown-hairy, as in the more strictly bracket-like 
forms. On many old Spruces there are deep clefts between the vari- 
ous bark scales, and in them sheets of the sporophores form whose folds 
fill the crevices completely, forming pores on the outer surface of the 
newer bark and the inner surface of the old scale. Growth takes place 
rapidly during the latter part of summer and early fall so far as could 
be noted. The hyphjB at the edge extend the area of the sheet, while 
those forming the walls of the pores grow vertically downward. 
Within the pores many hypha? grow into the holes, so that after a 
3"ear or two these are completely plugged at the base. There are at 
present no means of judging how old one of the sporophores described 
may orow to be. The oldest one found was about four-fifths of an 
inch {2"") in thickness. 

Trametes pi7ii forma ahletis was found ])ut rarely on the Fir. Its 
sporophores assume on this tree a different haliit from those on the 
Spruces. On vertical surfaces a distinct sessile pileus is formed, 
resembling a ])racket, rather than a hoof, as do those on the Spruce. 
The mycelium, after having grown throughout the heartwood, grows 
into the sapwood, where it flourishes much more vigorousl}" than in 
the Spruce because of the absence of resin. From the sapwood the 
hyphie enter the bark and break through it all over the trunk. At 
the points where they emerge they form small cushions, light red-brown 
in color, which are at first the size of a pin head, but rapidly increase 
in size (PI. XII, fig. 1). When barely /g of an inch (2 '"■") in width, a 
differentiation into an upper and lower surface takes place. A band of 



39 

veiy loosely interwoven hypha? grows out at right angles to the bark. 
From the loAver side of this band some hyph* split oil' and grow down- 
ward, adhering closely to the surface of the bark. Other hyph^ also 
turn down, growing faster at several points than at others, thus giving 
rise to small pits, which form the beginning of the pores. The pits are 
very variable in size. When they are still scarcely recognizable the 
hymenial layer begins to form in them, as evinced by the black cystidia 
which can be seen projecting from the lower surface of the band first 
mentioned even before any sign of a ridge is evident to indicate where 
the next pore is to be. Growth in these directions goes on rapidly. 
The hyphffi of the original band grow on horizontally, forming a 
rounded edge of loose hyph^e, which give the hairy appearance to the 
margin. At intervals, where the growth of the sporophore ceases, 
some of these loose hyphee stop growing, and when growth is resumed 
are left, forming a brush-like pi-ojection on the upper surface. These 
hyphse give the concentric appearance noted above for the Spruce. 
The hypha? on the lower side of the band grow downward to form the 
pores, and those adhering to the bark grow in the same direction, thus 
increasing the thickness of the pileus in that direction. A large num- 
ber of small cushions usually start together on thel)ark, many of which 
join as their edg«^s approach one another, forming a series of more or 
less imbi-icated sporophores (see PI. XII, fig. 1). On horizontal sur- 
faces the plicated form is lost, and sheets much like those found in 
the Spruce are formed. The pores in all the specimens on the Fir 
are more irregular than those found on the Spruce, but in all other 
important characters they are identical. 

On the White Pine the pileus is sessile and occurs at old knot holes. 

On the Tamarack both brackets and sheets are formed. The largest 
bracket forms found grew on the Tamarack; they often grow singly, 
and then again together, one above the other. One individual meas- 
ured 4 inches (10"") in width laterally, 2.8 inches (7 '"") from front to 
back, and 2 inches (.5 ''") in thickness at the back along the bark (PI. 
XII, fig. 2). The pores in the Tamarack specimens are exceedingly 
regular, far more so than in those of any of the other sporophores. 

The sporophores of Tixmietes pini forma ahietis grow both on living 
and fallen trees. They were found on trees which had been cut 
down four years before, and new ones were constantly appearing. 
It is this faculty of fruiting on dead trees that nuist enable tiiis fungus 
to spiead through a forest in a very short time, and accounts for 
the fact that it does so. After a Spruce has reached a certain age 
the chances that it will become affected with this parasite are, in 
the Maine woods, the very greatest. Older trees, i. e., Spruces which 
have reached a diameter of 10 to 12 inches, are more often subject to 
attack than younger ones. The fungus enters through any wound, 
and ai)parently spreads rapidly. There is no ('vidcMicc at ])rcsent to 



40 

show how rapidly it spreads, nor whether the (•haracteristic form of 
decay which it induces continues in wood after it has been cut from 
a tree or not. The present view seems to indicate that it does not 
grow after the death of the tree. 

HYIVIENIUM. 

Hartig ^ has given a very full description and numerous drawings 
of the hymenial layer of this fungus, and his observations can simply 
be confirmed. The basidia arise as slender hyphae, which gradually 
become much smaller at the apex and form four slender, rather long 
sterigmata, bearing the spores. These are colorless at first, but turn 
brown later on, and not infrequentl}" contain an oil globule in the 
center. The most striking elements of the hvmenial laver are the 
C3"stidia, called hairs by Hartig. They arise from internal hyphfe, 
which approach the hymenial laj^er at an angle. Pushing between the 
basidia and paraphyses one finds these large, pointed, brown, spine- 
like bodies, which project for a considerable distance into the pore 
canal (PL IX, figs. 2 and 3). They are thick walled and persist for a 
long time after the disappearance of the basidia and spores. 

As the pores grow older they are filled with a network of hyphse 
which grow out from the liody of the sporophore, growing over the 
hymenial layer and completely plugging the hole. The exact period 
when this takes place was not determined. 

POLYPORUS SULFUREUS ( Bull. ) Fr. 
OCCURRENCE. 

This fungus, although more frequently found on the hardwood trees, 
occurs now and then on living Spruces and brings about a brown rot 
of the wood of trunk and branches. The trees found were attacked 
after the trunks were 9 inches (23*^™.) in diameter. Entrance is efi'ected 
through wounds and broken branches, much in the same wa}" as the 
other parasitic fungi which enter above the ground. The mj^celium 
spreads through the trunk of an afi'ected tree, growing up and down, 
and reaching the highest branches in one direction and the roots in 
the other. No evidence of a diseased condition is usually visible on 
the outside, except such as noted for the other diseases. 

STRUCTURE OF DISEASED WOOD. 

Diseased wood is red-brown in color and can readilv be distino-uished 
from wood changed by the other fungi described by the fact that it 
breaks into slabs or flat pieces, which correspond each to an annual 
ring of wood (PI. XIII). The brown rotted wood is hard, verj^ brittle, 

1 Hartig, R. Wichtige Krankheiten der WaldbiiunK'. 50. pi S. 1874. 



41 

and }ireaks into more or less rectangular pieces. When in its final 
stages, it is exceedingly l)rittle and can be crushed to a tine powder in 
a mortar. It is always nuich firmer than wood destroyed by Polyporus 
schveinitzu and differs from the latter in the character of the cracks 
or breaks, which are most readih^ seen on a tangential view. 

The progressive changes which take place in the wood of a Spruce 
may be noted as follows: The wood at first turns slightl}^ red-brown 
in irregular patches, as seen when a trunk is split longitudinally. • 
These, patches grow larger, spreading from ring to ring and in a longi- 
tudinal direction along each ring. Small cracks next appear in these 
areas, extending part way through the thickness of each ring, both 
from the side of the spring and of the summer wood. These cracks 
are ver}- much more visi])le on the tangential view of an annual ring 
(PI. XI, fig. 1). At first but scattered cracks are to be seen extending 
longitudinally, which, however, soon elongate and pass both diagonally 
and directly across the direction of the fibers (PI. XI, fig. -I). At this 
stage the wood is still hard and has acquired a light-brown color. 
Immediately about the fissures it is more deeply colored than else- 
where. A microscopic examination shows that there has been great 
shrinkage in the volume of the cell walls and that the breaks and 
fissures occvir practically throughout the whole mass of the ])rown 
wood; though onh' the larger breaks are visible to the unaided eye. 
The shrinkage goes on rapidly, and after a time the tension becomes 
so great that the annual rings separate one from the other. A break 
usually occurs in a radial direction also, and as a result the free ends 
of the ring sw^ing outward. Breaks along the lines of the larger 
medidlary rays take place at the same time. This gives rise to long 
flat slabs of wood, each the width of an annual ring, Avhich hang 
together loosely at one end and at isolated points on their tangential 
walls (PI. XIII). Very ])adly decayed wood is so thoroughly traversed 
by larger and smaller breaks that it readily fails to pieces when struck. 
It nuist be noted, however, that the nature of the cracks is such that 
individual pieces of wood are, as it were, mortised into each other 
end to end, and this no doubt makes the wood as firm as it is. 

MINUTE CHANGES IN THE WOOD. 

The minute changes which the mycelium of Polyporus Hulfm^e\(i< indu- 
ces in the wood cells are such that the}' can not well be mistaken. It 
has been mentioned that the annual rings break into bands which curve 
inward as the ])rocess of drying goes on. A tangential view of several 
of these bands before they have broken will present an appearance such 
as is shown on PI. XI, fig. 4. A large munber of fissures have formed 
both across the wood fibers and parallel with them. The latter are more 
prominent — the cross fissures never occurring alone, but generally con- 
necting several longitudinal fissures. It will be noted that the Invaks are 



42 

characterized by sharp right angles, and in many places a stepladder 
arrangement is evident. In the early stages of attack the wood fibers 
turn red-brown and shrink. As a resvdt, tissures are formed in the 
walls of the tracheids, which extend diagonally across the wall at an 
angle of approximately 45 degrees (PI. XI, fig. 1). The medullary ray 
cells are at this period still intact, and hold together the more or less 
brittle wood libers. The next stage in the decomposition consists in the 
absorption of the medullary rays. This allows the wood fibers to con- 
tract more than up to that time, and as a result breaks occur. These 
breaks form at first so as to connect adjacent cavities left by the absorp- 
tion of the medullary rays. The wood fibers tend to curve in one direc- 
tion or another and break at the weakest point, namely, between two 
cavities, where the opportunity for curvature is greatest. What deter- 
mines the direction of curvature of the wood fibers has not yet been 
explained. In the illustration the curvature is toward the right. This 
curving has the efl'ect of bringing medullary rays which are in differ- 
ent longitudinal rows approximately into a line. Thus at •'«" two cav- 
ities are shown which are separated bj^ a curved fiber which sooner or 
later will break, uniting the two. At first two ray cavities are joined, 
then more, until long longitudinal holes are formed, such as are shown 
in fig. 4 of PI. XL The reason for the sharp angles' is now very 
apparent, likewise w^h}^ these fissure figures appear only on a tangen- 
tial view while on the radial view one simply sees the fissures as lines 
extending at right angles across a ring of wood (PI. XIII). 

The marking of the individual wood cells is a very regular one. 
The fissures extend through the secondary lamella, and at first sight 
remind one of those which the m3^celium of Polyporus schiceinitzii 
induces. The latter are very much steeper, however, and do not occur 
at such frequent intervals. 

The mycelium of Polyporm mlfureu.^ is colorless and is present 
only here and there in the wood cells, a fact to which Hartig calls 
attention. No spores, such as are so common when this fungus grows 
in Oak wood, were seen in the Spruce wood, although diligent search 
was made for them. 

FRUITING ORGAN. 

The sporophores of Polyporus sulfureus are among the commonest 
and best known of the largest fungi. The sulphur-yellow shelves of 
this fungus occur widely distributed throughout the United States, 
and are found in late August and September on many of the Oaks, 
Walnut, and other broad-leaf trees. A large number of sporophores 
usually appear together, one above the other, when growing from 
an upright trunk, or scattered here or there on a prostrate log. 
They grow on living trees and on the dead trunks also, for several 
years after the latter have fallen. A marked periodicity iu this respect 



43 

was noted for a particular tree during the past summer. This tree, a 
large White Spruce, had been blown down some years when first seen. 
The standing stump was 12 feet (3| meters) in height, and on its south 
side there developed in August of 1897 a large number of the sporo- 
phores. These dried and broke away during the following winter. 
During the summer of 1898 no sporophores appeared on either the 
standing stump or the fallen log, and it was not until August, 1899, 
that a new lot of the brackets appeared, and then in the greatest num- 
ber. Three large patches broke out on the north and northwest side 
of the trunk, and the lower side of the fallen log was literally covered 
with the yellow brackets. No mention of this periodical occurrence 
of the fruiting portion has been found, and it will be of considerable 
interest to see what will take place this year. Several other large 
Spruces in the immediate neighborhood were caused to decay by this 
fungus, but no sporophores have so far developed on their trunks. 

The shape of the pileus varies materially with the position which it 
happens to occupy. When on upright trunks several sessile sporo- 
phores usually occur one above the other, the upper surfaces of the 
lower ones touching and uniting here and there with the lower surfaces 
of those above. The individual parts are comparatively thin plates, 
which have radiating lines and depressions extending outward to the 
margin. The body of each is soft and fleshv when young and full of 
a clear yellowish liquid. The upper surface when 3'oung is verj^ 
moist, somewhat hairy, and when ])ruised turns brown. As the plant 
grows older it becomes verj^ much harder, and when completel}' formed 
is quite hard and brittle. Masses of the young plants have a peculiar 
fungous odor, which l)ecomes very intense as the parts grow older. 
The lower surface of the shelf is smooth and even. The pores are 
formed verj- early in its development, and almost as soon as thej' are 
completed the formation and discharge of spores begin. The sporo- 
phores are very short-lived. They l)egin to appear on the trunk as 
small I'ounded knobs, formed by thick-walled hypha?, which come out 
from between the bark scales. Their growth is very rapid, even more 
so than that noted for Polyporm schvjeinitzl i . The various small 
kno])s soon flatten into a number of plates, consisting of strands of 
hyphai, some of which grow out horizontally, increasing the width of 
the pileus, while others grow downward to form the pores. When 
the sporophores develop on the under side of a log they grow out in 
all directions from a central point, and sometimes forms with a distinct 
stipe are met with. 

Numerous drops of the clear liquid mentioned before were found 
hanirino- from the under surface of the shelves on some days.' The 
api)earance of the drops does not seem to stand in any relation to the 
amount of moisture in the air, for they weie found alike on very dry 



* Fries notes this fact — Epicrisis, etc. 450. 



44 

and very foggy days. The same sugar, melezitose, that was found in 
IWi/por>/s schweinitzil was obtained from the liquid in quantity. The 
fungus is attacked when barely mature l)y insects and small animals, 
and within a month after the ripening of the spores there is little of it 
left except the harder vipper surface of the shelves and the contracted 
basal portion. This may account for the fact that the spores ripen 
and are discharged so very rapidly. Cultures of spores made in 
water, in sugar water, and on bread showed no signs of germination. 
These experiments are to be repeated with better cultural facilities. 

The spores spread through the air and are carried to all parts of the 
forest. Wherever any wound or broken branch offers suitable condi- 
tions they germinate and induce the rot described. 

Polypmms, sulfureus was found only on trees growing along the coast 
of Maine. They were all older trees of the White Spruce. Further 
search will no doul)t show that it attacks the Red Spruce also, and 
possibly the other conifers. Its large, conspicuous sporophores make 
its recognition easy, and the fact that they are edible in their early 
stages ought to lead to their collection and destruction. 

POL.YPORTJS SUBACIDUS Peck. 

Poria subacida Peck, Thirty-eighth Report N. Y. State Museum. 92. 

OCCURRENCE. 

There are a number of fungi which attack standing trees and destroy 
their wood, of which it is not possible to tell, without continuous 
observation and experimentation, to what extent they are responsible 
for the death of trees, and whether they attack perfectly healthy trees. 
Among these belongs the fungus which for the present will be con- 
sidered as Poly2}(yrus subacidus Pk. It is one which is found on decay- 
ing logs of coniferous as well as other woods, ^ forming its pores in late 
summer and winter. It was found once on a living Hemlock^ twice 
on living White Spruce, and once within the trunk of a living White 
Pine. In many of the spruce forests hundreds of trees, particularly 
the younger ones, were found dead or dying. Man}^ of these trees 
were pulled up, and on their roots yellowish masses of mj^^elium 
were occasionally found. In one locality some thirty of these young 
trees, ranging from 2 to 10 inches (5 to 25 cm.) in diameter, had the 
wood of the trunk decayed by some fungus. The wood appeared 3^el- 
low, was very wet and spongy, and was easily pulled into shreds. No 
fruiting organs could be found. Several of the trunks were taken and 
sawed into pieces a foot (30 cm.) or more in length. These pieces were 
buried to the depth of a foot (30 cm.) in a sphagnum bank and were 
examined every week. Other trees were simply broken near the 

1 See Exsiccati, E. & E., N. A. Fungi. 



45 

ground and left standing, while in still others wounds were made with 
an axe to permit the entrance of air, as it was thought that fructifica- 
tion might thus be induced. After two weeks the ends of the pieces 
buried in sphagnum were covered with a white film of hyphte, which 
gradually turned yellow, and after two months began to form shallow 
pores. The same took place in practically every one of the trees which 
were overturned or wounded. In all the localities visited where trees, 
both older and younger, had been overturned, this fungus was found 
again, and again, and associated with it the form of wood decay 
described below. (Pis. XIV and XV.) 

Masses of yellowish mycelium were sometimes found growing out 
from under the bark scales of the roots of many healthy spruces in a 
way which seemed to indicate that they were ])egiiming to enter the 
root itself. Hypha3 from these masses extend into the soil, V)inding 
together the particles so that dense clumps are formed, varying from 
the size of a pea to as large as two fists put together. The growth of 
the hyphie in the soil is a very rapid one; they can be grown with 
ease in moist soil and form the peculiar lumps in a few weeks. Pieces 
of diseased trunks were buried in soil in a greenhouse in September, 
and in four months the hyphffi had grown through the soil of the bench 
in all directions. It is thus very evident that this fungus grows in the 
ground rapidly and that this is probably one of the ways in which it 
enters standing trees. This is made more probable by the fact that 
one finds all of the trees in a certain area affected with this fungus, 
both younger and older ones. Each probably infected its neighbor 
much in the way in which Polyporus sclviDeinitzii does. The fruiting 
portion of the fungus has been found on living White Pine, Red and 
White Spruce, Fir, and Hemlock. A large Hemlock, almost 2 feet 
(0.6 meter) in diameter (near Houlton, Me.), had been blown over and 
the trunk had broken some 6 feet (2 meters) from the ground. The 
wood was very soft and showed numerous black spots surrounded l)y 
white areas. The fruiting organs were forming in the chinks and 
crevices of the trunk, and on the stump. The tree was alive at the 
time it was seen. 

STRUCTURE OF DISEASED WOOD. 

The decay which the mycelium of this fungus induces is. not to be 
confused with that caused by any other fungus. Spruce wood when 
very much decayed is moist, almost wet at times, and can be comi)ressed 
nuich like a sponge, when (piantities of water will drip from the mass. 
Larger and smaller cavities of very irregular shapes, lined with a tough 
felt of hypha^ yellow on the inner side, are found throughout the 
wood. Such a cavity is shown in part at the bottom of PI. XIV, fig. 2. 
The cavities are scatt«M-ed throughout the wood in most triMvs and are 
generally partially filled with a pale straw-colored liciuid. The wood 



46 

itself dift'er.s markedl}' in ditferent trees. Ttiis difference appears to be 
due somewhat to the rapidity with which the solution of the libers 
takes place. As a rule, the wood in the early stages of the attack has 
numerous black spots scattered throughout its mass (PI. XIV, fig. 1). 
These black spots are surrounded by a white circle before long, and 
somewhat later disappear entireh', leaving very nuich larger white 
spots. The wood around the spots is now straw-\'ellow in color and 
begins to look somewhat frayed, as if groups of wood fillers were sepa- 
rating readily from the rest. A tendency for the different annual rings 
to separate now becomes very marked (PI. XIV, fig. 1, at the right), and 
a log of spruce wood at this stage can be split into concentric rings by 
mere pounding. Gradually the number of white spots increases. In 
one form of decay the white spots are confined almost entirely to the 
summer Avood. The newly formed spots are also in the summer wood, 
and l)efore very long all the summer wood of every ring, including 
also some of the adjacent spring wood of that ring, has turned white. 
This stage of decomposition is shown very well in PI. XIV, fig. 2, a 
longitudinal section of a spruce log, and in PI. XV, fig. 1, a cross 
section of the same log. It will be noted that the change to the white 
masses nowhere passes from the summer w^ood of one ring to the 
spring wood of the adjoining ring. There is evidenth' ^ome agent, 
presumal)ly of a chemical nature, which confines the solvent action of 
the fungus mycelium to the summer wood and prevents it from 
attacking the spring wood. It may be recalled here that where a 
similar change takes place in the spruce wood, induced by the mycelium 
of Traincttxi jjini forma ohkth (PI. X, fig. 2) 1)oth summer and spring 
wood were changed. This localized action of the dissolving agent takes 
place with such regularity and in so many different ways, depending 
upon the kind of fungus attacking the wood, that it suggests the 
presence of specifically distinct dissolving agents, enzymes, perchance, 
for each fungus. 

In the second form of deca}" the appearance of the white spots is 
limited to the summer wood in the same wa}' as above described. The 
white spots do not increase in number so rapidly and consequently do 
not form the white bands spoken of. Changes take place within the 
wood cells of the spring wood, which give to them a ver^^ light and 
porous nature. A cubic inch (16. -l*"") of such wood completely decayed 
weighs but 1.3 grams (sound spruce wood weighs 5.52 grams). 

The mycelium of the fungus spreads through the individual tracheids 
after entering the tree, and collects in spots here and there. Solution 
of the wood cells begins around these centers, which at this time appear 
dark brown or black. They are the black spots referred to above. 
The change which takes place around these centers consists in a solution 
of the hadromal and the other lignin constituents of the cell walls, 
leaving the pure cellulose fibers free from one another. These con- 



47 



stitute the white spots and also the white ))ands spoken of. The 
various steps leading to the complete separation of the cellulose fibers 
are exactly those which have been described for a similar process 
caused by the hyphee of Trametes pini 
forma abietln. 

A xc^vj different change is going- on at 
the same time in the spring wood, and 
gradually spreads from this to the sum- 
mer wood. This change may be likened 
to the one which Hartig has described as 
taking place in pine wood attacked })y 
PoJyjyortis horealix..^ The hypha? of the 
fungus develop in the wood cells with 
great rapidity, filling them completely. 
Numerous hyph« pass through the walls 
in all directions, making large irregular 
holes many times the diameter of the 
hypha^ which pass through them. The 
secondary walls of the Avood cells are 
gradually dissolved; a faint granular 
appearance of the walls is seen at first, 
and little by little the walls become thin- 
ner. At last only the primary lamelhi is 
left, and in the bordered pits the torus 
(PI. XI, fig. 3). The whole wall finally 
disappears, leaving simply that part of 
the wall belonging to two or three cells, 
namely, the portion having a triangular 
cross section. This solution of the walls 
goes on sinudtaneously throughout large 
areas. The medullary rays disappear 
completely, long before the wood cells are 
entirely gone. The spaces left by the 
dissolved cells are rapidly filled with 
hypha^ and these hold poi'tions of the cell 
walls not yet destroyed in place, and 
give consistency to the mass, which thus 
retains th(> shape of the wood befoi-e the 
attack. The whole mass can be compressed by slight pr(\ssurc and 
will not return to its original size. This accounts for the extremely 
light weight of wood thus decayed. In PI. XI, fig. 2, a radial view 
of wood in an advanced stage of decay is shown. The straight black 
lines indicate groups of wood vessels, two or more; the hyphai between 




Fig. 8.— Baso of spruce brnnoli, sliowing 
its resistance to the attack of tlie my- 
celium of Polyporus subacidug Fk. 



' Hartig, R. Zeraetzuiigserscheinungeii dcs Ilolzes, etc. 



48 

them have dissolved out the missing fibers and now fill the spaces. 
Plate XI, fig. 3, represents a cross section of similarly attacked spruce 
wood, showing several wood fibers of the spring wood at one side and 
the gradual dissohition of adjoining ones, leaving onl}^ the more resist- 
ant portions which lie free in the masses of hyphte. These remaining 
parts stain with phloroglucin and hydrochloric acid, showing that they 
are still lignified walls. Heartwood and sap wood of the spruce are 
destroyed with equal rapidity. All parts become spongy, with the 
exception of the resinous basal pieces of the branches, which resist the 
attack of the fungus even after the whole trunk has been destroyed. 
This resistance of the basal pieces of the branches is quite a common 
feature in diseased trees attacked by several other fungi, notal)ly 
Polyparus schwelnitzii^ but nowhere is it more striking than in this 
instance. Text figure 3 shows such a branch piece as it appeared 
immediately after pulling it from a dead standing tree. 

FRUITING OKOAN. 

After the mj'celium has invaded the sapwood it grows out over the 
bark, forming yellow felts. This takes place in the early part of the 
summer, generally about July. A few weeks later the small pores 
begin to form. Certain hypha? of the sheet turn at right angles to 
it and grow out at this angle, forming shallow pores. These are 
almost round and are separated by ver}- thin dissepiments. Fig. 2, 
PL XV, is from a photograph of a spruce log, about the middle of Sep- 
tember, almost natural size. As the season progresses the fungus 
dies and splits up into smaller areas and some of the tubes become 
inclined. No pores occur at the edge of the sheet, thus leaving a 
fringe of sterile hyphae. This distinguishes this fungus from many 
allied forms. The hymenial layer and the pores are generally straw 
yellow, sometimes even more decidedly yellow, the color deepening 
toward the latter part of the fall. The pores do not form until 
December or January, and as a completely fruited fungus was col- 
lected but once, its description will be deferred until more material 
has been seen. 

The fruiting organ frequenth^ develops in cracks and breaks formed 
when a diseased tree is blown over. Fructification was induced in 
many instances, as described above, b}^ allowing the air and moisture 
to have access to completely decayed wood. 

When PoJijporuH siihacidus grows in Northern forests on dead conif- 
erous wood as a saprophyte, its habit and action difi^ers somewhat from 
that described above. Inoculation experiments were made during the 
summer to test how rapidly this fungus destroys sound wood. Dis- 
eased wood from both dead and living trees was placed in holes bored 
in healthy spruces, and the latter were labeled so as to be readily iden- 
tified in later years. The amount of destruction which this fungus does 



49 

in the spruce forests is very large, but careful experiments will have 
to ])e made to determine its relation to trees weakened by other causes, 
also its progress through the soil from tree to tree. 

KEMEDIES. 

This fungus ma}^ be accounted most destructive to dead timber, and 
any remedies spoken of for Polyporus plnicola apply here. Dead 
trees should be utilized before the chance for infection becomes too 
great. No practical remedies can be suggested at present to prevent 
its spread through the soil. 

OTHER DISEASES. 

Besides the diseases described in the foregoing there are a num])er 
of others of which not enough was seen to enable a full description to 
be given. 

POLYPOEUS VAPOKARIUS (PERS.) FK. 

This is frequent on Spruces and Firs, and induces a brown rot of the 
sapwood. The fungus occurs widely spread over the United States 
and Canada on all coniferous woods. Its fruiting body is very 
variable, and there are probably many fungi included under this name 
which do not belong there. From observations made in the Maine 
woods it seems that this fungus attacks dead much more than living 
trees, destroying them for timber very rapidly. A fuller description 
of it will be given at a later date. 

POLYPORUS ANNOSUS FR. 

This fungus is a parasite of European trees much feared by the for- 
esters of the Continent. Diligent search was made for it, but fully 
formed fruiting ])odies were not found. A single Spruce seen on the 
top of Mount Kineo, Moosehead Lake, had its roots covered with tirm 
leathery sheets, such as PoJyjJoi'u.s annosus sometimes forms on the 
roots of the Southern Pines. Unfortunately there were no means at 
hand to cut down the tree, so that an inspection of its trunk was 
impossible. Other diseased trees of Spruce and of the Fir were seen 
north of the Kangeley Lakes. One of those Avas overturned, having 
grown in a dami) locality. Its roots were covered with the yellowish 
leatherv felts which extended into the surroundino- soil. The trunk of 
this tree was completely rotted in the center, th(> decay going up the 
trunk for 25 feet (almost S meters). At this point the wood was brown, 
showed some white areas, and smelled strongly of prussic acid. The 
stumps of many other Spruces were examiniHlfor evidences of this fun- 
gus. Some S})ruces were found which had small holes in the sunnner wood 
of many annual rings. The wood when cut longitudinally showed many 
of thes(> holes, which dUl'ered fioni those formed by Ti'dtitctea pln'i. 
577r) No. 25 4 



50 

Thoy (x-cuiit'd chieHy in the .summer wood, and were lilled with a red- 
brown powder. There is no Avhite lining as in the wood attaeked by 
Trametes jy'mL Black spots appear here and there in the wood, and 
when they disappear the holes take their place. The holes increase in 
size and number, and in the last stages of decomposition the wood has 
become a shredded mass of yellow-brown fibers, which feel much like 
straw. It is completely honeycombed in ever}" direction. The annual 
rings of wood separate from one another, forming thin plates per- 
forated by thousands of small holes. The transformation of this 
fibrous material takes place from the root up into the trunk for from 3 
to 20 feet (1 to 6 meters). In some trees the innermost rings of wood 
are afi'ected. As the wood becomes more and more rotted a hole is 
formed wdiich gradually increases in diameter, eventually sometimes 
becoming so large that the weakened trunk is blown over by the wind. 
On other trees one or the other side of the trunk may be affected. 
Two or more separate holes may be formed which join near the base 
of the tree. 

A more lengthy description of the changes in the wood just described 
is not deemed necessary, in view of the fact that the active agent which 
brings about the changes is as yet not fully determined. If it proves 
to be P(Ayp(>rui< nnno^im Fr. it would seem that the injuiy done in the 
Eastern forests by this fungus is not A'ery large, which may be con- 
sidered a fortunate circumstance, as this fungus is one naturally to be 
dreaded h\ the forester, as it is combated only with the greatest diffi- 
culty and expense. 

AGARICUS MELLEUS VAHL. 

Many trees were fovuid in which the well-known rhizomorph strands 
of this fungus grew under the bark. The summer of 1899 was exceed- 
ingly dry. and on that account the development of Agaricinese of all 
kinds was a very meager one. On the various excursions made through 
the Maine forests but one tree was found on which the yellow fruiting 
organ of this fungus w\as developing. The manner in which this fun- 
gus grows on the roots of the trees and brings about their death has 
been so fully described b}" Hartig and others that it seems hardly 
necessary to describe it here. The fungus grows within the living 
roots and cambium of a tree and speedily brings about a disturbance 
in its absorbing organs which results in ultimate death. The wood is 
rarely if ever affected to any extent, so that lumbermen use the dis- 
eased trees for lumbering purposes, making no distinction between 
them and live trees as long as the wood is entirelj^ sound. Diseased 
trees should be cut at once when recognized. 



51 



CONCLUSION. 



The conditions in the New England forests are very favorable to the 
growth and development of timber-destroying fungi, conditions which 
are made still more favoralile by an ever increasing supply of dead 
wood. Radical changes will be necessary in the present lumbering 
methods in certain localities before any betterment can be hoped for. 
During the summer of 1899 the wasteful cutting of timber was noticed 
in particular in the region north of the Moosehead Lake, where the old 
S3^stem of measuring logs by the top scale is still in vogue. The lum- 
berman cuts the logs on the stumpage plan, and in his endeavor to 
obtain as high a scale as possible he cuts the tree high up on the trunk 
and low in the top, leaving almost half the top in the woods. This is 
not only wasteful lumbering, but ofl'ers an excellent opportunity for 
the development of several of the fungi described in the foregoing 
pages. From the dead trunks and limbs their spores spread to stand- 
ino- trees which mio-ht otherwise remain sound. The same is true for 
the insects, as recently pointed out by Hopkins.^ 

In the foregoing it has been pointed out that as trees grow older 
they become more liable to insect and fungus attack. An old tree has 
many vulnerable points, such as old branches and wounds made by 
animals or by hail, where insects or fungi may gain entrance to begin 
their work of destruction. 

As a tree grows older the chances that it will be attacked become 
greater. This point ought to be taken into consideration in the 
harvesting of a timber crop. In certain sections of the Maine forests, 
particularly in the Rangeley Lake region, the trees have reached an 
age where it appears that the rate of annual accretion, and con- 
sequently the annual increase in value, is very small, while the danger 
of infection is increasing every year. It is recommended that such 
trees he cut immediately where practicable, as they are practically ripe 
and proba))ly at their point of greatest value. This may not alwaj^s 
])e possil)le, owing to practical difhculties in reaching water courses, 
etc., but the principle should ])e established that it will prove more 
protitable in the long run to cut trees after they have reached a certain 
age, to prevent depreciation due to the attack of fungi or insects. 
Future investigation will have to determine what the exact age is at 
which it will be most profitable to do this cutting. 

It has also been pointed out that there are several fungi which attack 
trees after they have been killed by insects or other agents. This is of 
gi-eat practical significance, for it may often l)e possible to harvest such 
dead trees before the fungus in question has had time to l)egin its work. 



' Hopkins. A. I). Ptvliininary Report on llic Insect p]neniies of the Forests of the 
Northwvst. I'.iil. No. 21, Div. of ImiLpiiiuIo^'v, V. S. Dcpt. Agr. 181)9. 



52 

In the Maine forests great areas of forest lands were killed hy bark 
beetles some years ago. If the dead trees had been cut shortly after 
their death, the timber might have been utilized, and it would have 
been as valuable as that from live trees, for the beetles do not mine in 
the heartwood. This was not done, however, and before long the 
whole forest of dead trees was rendered worthless by several fungi, 
notably Polypm^ics pinicola and Polyporus suhaoidm. What is true of 
larger areas holds for individual trees in the forest, and also in those 
sections where strong winds blow over many trees. Such an area, 
technically known as a windfall, offers opportunities for the action of 
destructive fungi, and the same recommendations just made for areas 
where trees are destroyed by insects hold good. A dead tree is as 
valuable as a live tree, provided its wood is sound, and it ought to be 
cut immediately. There is some prejudice among lumber bosses that 
such trees are of no account; nothing can be further from the truth, 
and this fact ought to be insisted on by those in charge of cutting 
operations. 

The trees, now in the forest, which are diseased are beyond help, and 
it is at present neither practical)le nor economical to practice the 
methods in use by the European foresters, which consist in the prompt 
removal and destruction of the diseased trees. The time will come 
when this may prove protital)le in the regenerated forests, but for the 
present the most hopeful method of combating fungi is by conservative 
lumbering. Men who are acquainted with the manner in which insects 
and fungi work and who can direct the cutting operations ought to be 
employed. 

It may not be out of place here to refer to the growing sentiment in 
favor of restricted cutting, which was very much in evidence in the 
localities visited. Much agitation is still going on decrying the lum- 
berman as the greatest enemy of the forest; but with the growing reali- 
zation that it is possible to utilize the timber of the forest and still 
leave a forest which will yield timber from year to year, this feeling 
is gradually lessening. The lumberman has not been slow in realizing 
that restricted cutting will be more economical in the long run than the 
indiscriminate destruction of the past years. It is gratifying to note 
that two of the largest lumber owners of western Maine are employ- 
ing trained foresters, under whose directions the cutting operations are 
carried on.^ These men will not only be able to make operations more 
prolitable, but can also aid in gathering information which may go to 
solve many of the problems still to be unraveled in connection with the 
enemies of forest trees. 



1 See also Graves, Henry 8. The Practice of Forestry l)y Private Owners. Year- 
book, Dept. of Agr. 1899: 415. 1900. 



53 

EXPLANATION OF PLATES. 

platp: I. 

Fig. 1'. Sporophores of Polyporiij^ ^clavemitzii Fr. 

Fui. 2. A piece of the bark of Red Spruce with sporophores of Polyporun volvntun 
Peck growing from holes forinetl by a boring beetle, a species of Deiidroclonua. 

PLATE II. 

Cioss section (X|) of the trunk of a living young Balsam Fir [Abies halsamea (L. ) 
Mill.) at a point 4 feet (1.2 meter) from the ground. Decay, caused by Polyporus 
sclnreluitzii Fr., has shrunk the wood, jjroducing a number of cracks and giving it a 
rough appearance. It is so nonresistant that the saw tore the fibers instead of cut- 
ting them. The large crack at the top, extending through the sapwood, was formed 
when the tree was cut down. A small sporophore of the fungus grew at the base of 
this tree. 

PLATE III. 

Radial view (X j) of a log of White Spruce (Picea canndnisi.'i (L. ) B. S. P.) , showing 
an early stage of decay induced by the mycelium of Polyporus pinicola (Swartz) Fr. 
The fine parallel lines indicate the annual rings of wood. Here and there white spots 
with darker centers are seen; likewise long white lines parallel to the course of the 
wood fibers, and others near tlie center of the figure, which extend in an irregular 
manner across the direction of the libers. 

PLATE IV. 

Radial view (Xz) of a log of White Spruce {Picea canadensis B. S. P.) , showing an 
advanced stage of decay induced by mycelium of Poly poms pinicola (Swartz) Fr. 
The wood has cracked throughout. The white masses are sheets of mycelium. At 
the right of the figure two sporophores are shown — one just beginning to develop, 
the other about 1 year old. The sapwood has been partially destroyed by boring 
larvse, whose tunnels are filled with sawdust. 

PLATE V. 

Three sporophores (Xj) of Polyporus pinicola (Swartz) Fr. The uppermost one 
is a young one. The one on the right is growing on a stump, and its lower surface is 
much eaten by insects. The one on the left is a very old sporophore, in which the 
ridged ujtper surface is very marked. 

PLATE VI. 

Fig. 1. Radial view of a piece of wood (natural size) of the Red Spruce (Picea ruhens 
Sargent), showing an early stage of the decay induced by the mycelium of Trainrtes 
pini ( Brot. ) Fr. forma ahietix Karsten. The white spots indicate where the wood luus 
been (rhanged so as to leave cellulose fibers. Small black lines are visible here and 
there. 

Fig. 2. Radial view of Red Spruce log (natural size), showing advanced stage of the 
same decay. The mimber of white spots has increased. Tlu' decay rarely goes 
beyond this stage. 

PLATE VII. 

Radial view of a lug uf i'.alsain i'ir ( .lA/Vx Ixilsunird (!,. ) Mill.), shitwing advanced 
stagi' iif ilccay due ti> '/'ndiuiis />iiii { ilnil. | l''i-. f<ii-iiia (thiilis Karsten. 



54 

PLATE VIII. 

Fig. 1. Piece (X|) of wood of tamarack or larcli { Larlx I'tricina), showing early 
stage of the decay caused by TrameUss p'nu (Brut.) Fr. forma ahlelis Karst. Note 
how the annual rings separate at one end. 

Fig. 2. Piece (X|) of tamarack wood, showing an advanced stage of the same 
decay. The piece is composed of very little sound wood; the larger portion is 

cellulose. 

PLATE IX. 

Fig. 1. Radial view of two spruce tracheids, showing the manner in which cracks 
appear in the walls when such wood is destroyed by Polyporus sclmehutza Fr. 

Fig. 2. A pore from the sporophore of Trametes pin'i ( Brot. ) Fr. forma aUetU Karst., 
growing on Ahii's Ixdmmm, showing numerous cystidia projecting from the hymenial 
layer. 

Fig. 3. Enlarged view^ of a portion of the hymenial layer shown in fig. 2, showing 
cystidia with thick walls and several basidia with spores. 

Fig. 4. View (Xj) of the lower surface (jf an old pileus of Polyporus pinicola 
(Swartz) Fr., of which a portion has died. This is shaded dark. Hyph?e from the 
living parts are forming a new layer, which is slowly covering the dead parts. The 
pores are indi(;ated by the dots. 

FiG. 5. Young sporoplKjre (natural size) of Polt/porna pinicola, cut in the middle 
to show arrangement of pores and top. 

FiG. 6. Resupinate form (natural size) of pileus of the same fungus. 

Fig. 7. Older pileus (natural size) of the same fungus, sectioned through the 
middle. 

Fig. 8. Diagrammatic representation of a section through the pores of Polyporus 
pinicola. They are continuous from year to year. A firmer layer of hyphte, 
incrusted with crystals of oxalate of lime, forms a line of demarcation between 
successive growth increments. 

Fig. 9. Cross section of wood elements from summer wood of Spruce {Picea ruhnia 
Sarg. ) attacked by Tratiicl>'s jiiiii iormsi ahidis, showing how the fibers are grachially 
changed until only cellulo.se is left; " w," unchange<l w(jod libers; "b," the outermost 
lamelU* (unshaded) now consist only of cellulose; "c," more advanced stage; "e," 
the middle lamella is being converted into cellulose, and is finally absorbed, leaving 
only portions " p" free among the white cellulose libers. 

Fui. 10. Radial view of tracheids from wood of Spruce {Picea ranademia (Mill.) 
B. S. P.) attacked by Trametes pirn forma abielis, in tlie region of a hole fringed by a 
black line. (See PI. VI, fig. 2.) The tracheids are filled successively with hyphse, 
which are incrusted with a brown material so as to completely plug the tracheitl. 

Fig. 11. Tracheid from wood of Spruce {Picea canademift (Mill.) B. S. P.) during 
early stage of attack by Trametes pini forma abietis, showing hyphse. 

Fig. 12. HymeniaWayer oi Polyporus pinicola (Swartz) Fr. 

Fig. 13. Radial view of white area from wood of Balsam fir (Abies bahamea (L. ) 
Mill.) attacked by Trametex pini (Brot) Fr. forma abietis Karst., showing how the 
hyphfe gradually recede from a center, forming plugs in every wood element. The 
pings are colored almost black 1)y a brown product of decomposition. 

PLATE X. 

Fig. 1. Cross section of Spruce wood partially destroyed by mycelium of Polyporus 
pinicola. Large cavities and breaks which are filled with fine hyphse are being 
formed in the wood. The summer wood is indicated l)y the parallel shading, the 
hyphic )jy dots; "c," a small fi.ssure enlarged in text figure 2. The lines at the 
left =0.5""". 



55 

Fig. 2. Cross section of a pwre of Spruce wood, showing early stage of destruetion 
by Trainctrs 2>>nl forma (thirds. Parallel lines of holes filled with cellulose fibers, here 
indicated Ijy dots, appear in the wood. The black lines bounding the cavities siniplj^ 
indicate the limit of change of cellulose, for in reality there is no such sharp line of 
demarcation. The short line at the right equals about 25 of an inch (1™"'). 

Fk;. 3. Later stage of the same form of decay. The wood is now simply a network 
of narrow wood lamelhe separating larger and smaller holes. In these lamelUe ]>lack 
lines are shown, which represent plugs of brown hyphfe incrusted with decomposition 
products. (See PI. IX, figs. 10 and 13. ) Cellulose fibers and mycelium fill some of the 
cavities. The short line at the base equals about ^V of an inch (1'"'"). 

Fig. 4. Longisection of wood (Spruce), showing effects of destruction by hyphje of 
Polyporus pinicola. 

Fig. 5. Cross section of several wood cells, showing changes which take ])lace in 
wood such as shown in fig. 4. 

PLATE XL 

Fk;. 1. Tangential view of Spruce avoo<1 destroyed by mycelium of PoIi/jkh'uk snJ- 
fureus (Bull) Fr. : "a" wood elements which have been curved, bringing two med- 
ullary rays into line; " e" part where a break occurred, uniting two medullary rays. 

Fk;. 2. Radial view 01 wood in last stage of decay, induced by mycelium of Poli/- 
jwnis Kiihitriilus Pk. The straight lilack lines represent one or more wood elements 
held in i)lace by the hyplue wliich are wound all around them. Remnants of medul- 
lary rays are to be seen here and there. 

Fk;. 3. Several cells from such a piece as is shown in fig. 2 (also PI. XIV, fig. 3). 
Normal wood cells of the spring wood are shown at the left, and going toward the 
right various stages in the solution of the cell walls. 

Fk;. 4. Tangential view of a piece of Spruce wood destroyed by mycelium of Poly- 
porus sulfureus, showing characteristic breaks in the wood, formed by the uniting of 
many medullary rays by cross breaks. (See fig. 1 of this plate.) The short line at 
the left is equal to l'""'. 

PLATE XII. 

Various forms of sporophores of Tixnnck's phil forma abietis. 

Fig. 1. On Balsam Fir. 

Fk;. 2. On Tamarack. 

Fig. 3. On horizontal branch of Spruce. 

Fig. 4. On bark (jf trunk of Spruce. 

Fk;. 5. At base of dead branch of Spruce. 

Fk;. t). Semipileate form on Spruce. 

Fig. 7. At base of dead branch of Spruce. 

PLATE XIII. 

Radial view <if a lilock of White Spruce {PIrea rxiiftilrnsis (Mill.) B. S. P.) partly 
destroyed by mycelium of J'n/i//)(triis sulfureus. The darker spots at one side show 
where the wood turns brown and ultimately cracks. The manner in which the 
annual rings sejjarate is indicated near the top of the figure. 

PLATE XIV. 

Fig. 1. Radial view of White Spruce {Picea ainadensis) , showing early stage of 
destnu;tion by Polyporus suhncidus Pk. 

Fk;. 2. Radial vicnv of White Sjiruce log showing ilestruction of wood by mycelium 
of Polyporus subacidus I'k. The white lines show where the wood has been so 



56 

changed as to leave cellulose fibers. Near the bottom of the figure note a cavity 
lined with mycelium. 

Fig. 3. Radial view of White Spruce wood decayed still further by the same fungus. 
The wood is soft and flaky and is being changed to cellulose here and there. 

platp: XV. 

Fig. 1. End view of a Spruce log similar to the one shown on Plate XIV, fig. 1, 
showing how the summer wood of every annual ring has been changed, leaving cel- 
lulose fibers. 

Fig. 2. View (about natural size) of the resupinate sporophore of Polyporus mbaci- 
dus Pk. on Spruce log, showing how it creeps over the bark. 

O 



Bull. 25, Div. Veg. Pnys. 6c Path., U S. Dept. of Agricu 



ture. 



Plate I. 




Fig. 1.— Sporophores of Polyporus schweinitzii Fr. 




Fig 2.— Polyporus volvatus Peck, growing from holes made in the bark 

BY DENDROCTONUS SP. 



Bui. 25, Div. Veg. Phys. &. Path., U, S. Dept. of Agriculture. 



PLATE n. 







Log of Balsam Fir showing decay caused by Polyporus schweinitzii Fr. 



Bui. 25, Div, Veg. Phys. 8c Path., U. S. Dept. of Agriculture. 



PLATE III. 




I. I ,i; 



Log of White Spruce showing early stage of decay caused by 

POLYPORUS PINICOLA (SWARTZ) Fr. 



Bull 25, Div. Veg. Phys. & Path., U. S. Dept of /Sg,, culture 



PLATE IV. 




Log of White Spruce showing advanced stage of decay caused by Polyporus 

PINICOLA (SWARTZI FR. 



Bull. 25, Div. Veg. Phys. & Patn., U, S. Oept of Agriculture, 



Plate V. 



CO 

■V 
o 

O 

■a 

I 
o 

3) 
in 

CO 

O 
-n 

■V 
O 

r 
-< 

T3 
O 

33 

C 

00 



o 
o 



CO 
> 

33 



Ti 

33 




Bui. 25, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



PLATE VI. 




k'^^^itjiim 




Fig. 1. Red Spruce: Early stage of the decay caused by Trametes pini forma abietis 








Fig 2. Red Spruce: Advanced stage of the decay caused by 
Trametes pini forma abietis. 



Bui. 25, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



PLATE VII. 




Log of Balsam Fir showing decay caused by Trametes pini forma abietis. 



Bui. 25. Oiv. Ve|, Phys. & Path., U. S. Dept. of Agriculture. 



PLATE VIII. 





FIG. 1. FIG. 2. 

Fig. 1 EARLY STAGE AND FIG. 2 LATE STAGE OF DECAY OF LARCH CAUSED BY 
TRAMETES PINI FORMA ABIETIS 



Bull 25, Div, Veg. Phys. & Path,, U, S. Dept. of Agriculture. 



Plate IX. 




POLYPORUS SUBACIDUS PK., POLYPORUS PINICOLA 'SWARTZl FR., AND TRAMETES PINI 

(Brot.) Fr. forma abietis Karst. 



Bull. 25, Div. Veg. Phys. & Path., U, S Dept. of Agriculture. 



Plate X. 




Work of Polyporus pinicola iSwartzi Fr. and Trametes pini iBrotj Fr. forma 

ABIETIS KaRST 



Bull. 25, Dlv. Veg, Phys. & Path., U. S. Dept. of Agriculture. 



Plate XI. 




Stages of decay induced in Spruce by Polyporus subacidus Pk. and Polyporus 

suLFUREus I Bull. > Fr. 



Bull. 25, Div, Veg. Phys & Path , U, S. Dept. of Agricultuie. 



Plate XII, 






& ( 7 



I^ 



Various i-ciHMh of sporophores of Trametes pini i Brot.) Fr. forma abietis Karst. 



Bui. 25, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



PLATE XIII. 




Block of White Spruce wood showing injury caused by Polyporus sulfureus. 



Bui. 25, Div. Veg. Phys. & Path., U. S. Dept. of Agriculture. 



PLATE XIV. 




FIG. 1. 





FIG. 3. 
Fig. 1 EARLY STAGE AND FIGS. 2 AND 3 SUCCESSIVELY LATER STAGES OF THE DECAY 

CAUSED IN White Spruce by Polyporus subacidus Peck. 



Bui. 25, Oiv. Veg. Phys. & Path., U. S. Oept. of Agriculture. 



PLATE XV. 




Fig. 1. Cross section of log of Spruce showing decay caused by 

POLYPORUS SUBACIDUS PECK. 




Fig. 2. Resupinate form of sporophore of Polyporus subacidus Peck 

on Spruce log. 



Bulletin No. 26. 



V. P. P. 79. 



U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

ALBERT F. WOODS, CHIEF. 



WAKKER'S HYACINTH GERM. 

Pseudoinonas Jiyacinthi (Wakker). 



BY 



ERWIN R SMITH, 



BOTAAitt^ML 



IN CHARGE OF LABORATORY OF PLANT PATHOLOGY. 



Issued February 21, 1901. 




WASHINGTON: 

GOVKRNMENT PRINTING OFFICE. 
I 90 I . 



OFFICE OF PLANT INDUSTRY. 

B. T. Galloway, Director. 

AFFILIATED DIVISIONS. 

Gardens and Grounds, B. T. Galloway, Superintendent. 

Vegetable Physiology and Pathology, Albert F. Woods, Chief. 

Agrostology, F. Lamson-Scribxeb, Chief. 

Pomology, G. B. Brackett, Chief. 

Section of Seed and Plant Introduction, Jared G.- Smith, Chief. 



DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 



SCIENTIFIC STAFF. 

Albert F. Woods, Chief of Division. 
Mertox B. Waite, Assistant Chief. 

associates. 

Erwin F. Smith, Wm. A. Orton, 

Newtox B. Pierce, Ernst A. Bessey, 

Herbert J. Webber, Flora W. Patterson, 

M. A. Carleton, Hermann von Schrenk,i 

P. H. Dorsett, Marcus L. Floyd.^ 

Thos. H. Kearney, jr. 

in charge of laboratories. 

Albert F. Woods, Plant Physiology. 
Erwin F. Smith, Plant Pathology. 
Neavton B. Pierce, Pacific Coast. 
Herbert J. Webber, Plant Breeding. 

1 Special agent in charge of studies of forest-tree diseases, cooperating with the Division of 
Forestry, U. S. Department of Agriculture, and the Henry Shaw School of Botany, St. Louis, Mo. 

2 Detailed as tobacco expert, Dirision of Soils. 



Bulletin No. 26. V. P. P. 79. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION '' VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

ALBERT F. WOODS, CHIEF. 



WAKKER'S HYACINTH GERM, 

Pseudojiioiias hyacinthi (Wakker). 



BY 



ERWIN F. SMITH, 



IN CHAROE OF LABORATORY 6f PLANT PATHOLOGY. 



Issued February 21, 1901. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
I 90 I. 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 
Division of Vegetable Physiology and Pathology, 

Washington, D. C, October 6, 1900. 
Sir: I respectfully transmit herewith and recommend for publica- 
tion a report by Dr. Erwin F. Smith, of this Division, on a bacterial 
disease of hyacinths commonly known as "the yellow disease" or 
"Wakker's disease." 

The fact that large numbers of hyacinth bulbs are forced each 
year in the United States makes it desirable that their diseases be 
understood. The information gained regarding the biologj^ of the 
organism will also be of great value to those investigating the bacte- 
rial diseases of plants. 

The report confirms earlier work done in the Netherlands and adds 
much new and important information respecting the nature of the 
parasite. The latter belongs to a group of bacteria, hitherto but little 
studied, several members of which (also studied by Dr. Smith) cause 
diseases widely prevalent in the United States. 

The report while primarily for pathologists and bacteriologists will 
also be of interest to florists and any others who wish to detect this 
disease and to avoid its introduction into the United States. 
Respectfully, 

Albert F. Woods, 
Hon. James Wilson, Chief of Division. 

Secretary of Agriculture. 



PREFACE. 



This paper was prepared for publication in August, 1897, at which 
time I had secured characteristic infections and had worked out many 
of the cultural and other characters given in the following pages. 
The fact that I had not again produced the disease with germs isolated 
from mj^ first series of infected plants, the further fact that I could 
not satisfactorily explain the meager growth of the parasite in the 
host plant, and on steamed j)otato and the other culture media which 
I had used, and, finally, a shadow of doubt concerning the accuracy 
of two or three other observations, induced me to withhold tlie paper 
and repeat the experiments. In the time which has intervened I have 
gone over nearly or quite all of the experiments detailed in the origi- 
nal paper, without, however, discovering any serious errors. During 
this time reinfections have been secured, the reason for the feeble 
parasitism lias been discovered, and a number of other interesting 
facts have been brought to light, so that the long delay of publication 
has not ])een without its comiDensations. 

Throughout this study numerous comparisons have been made 
with two other yellow bacteria, Pseudomonas campestris and Ps. 
phaseoU, and occasional mention has been made of them in this paper, 
both being plant parasites. Occasional comparisons have also been 
made with other bacteria, especially with Ps. Stewarti. The leading 
cultural characters of the hyacinth organism are mentioned in the 
synopsis at the end of this paper, but it has been decided to relegate 
an account of the numerous experiments on which these conclusions 
rest to a second bulletin, which is now ready for publication and in 
which they will be discussed in connection with the cultural pecu- 
liarities of the other yellow species of Pseudomonas here mentioned. 

It is too much to hope that this bulletin is entirely free from mis- 
takes. Nevertheless great pains have been taken to make it trust- 
woi'thy, all of the experiments having been performed in duplicate, 
and iiearlj^ all of them having been repeated several times on differ- 
ent occasions to eliminate unsuspected sources of error. 

Some brief statements respecting the morphology and physiology of 
this organism, as determined by the writer, were made at the Detroit 
meeting of The American Association for the Advancement of Science 
in August, 1897, and were pul)lished in tlie Proceedings of the Associ- 
ation for that year (Vol. XLVI, 1897, Salem, June, 1898). 

Erwin V. Smith. 
5 



CONTENTS. 



Page 

Historical ... 9 

Source of material _ 10 

Inoculations of 1 897 ... 10 

Series 1 (hyacinths) 10 

Series 2 (onion) .. 18 

Natural infection of a daughter bulb _ 18 

Inoculations of 1898 19 

Series 3 (hyacinths) 19 

Series 4 (onions) .. ._ 20 

Series 5 (hyacinths) 20 

Series 6 (Roman hyacinths) /. 23 

Series 7 (hyacinths) 28 

Series 8 (hyacinths) 25 

Series 9 (hyacinths) 26 

Series 10 (hyacinths) 26 

Series 11 (cabbage) .. 27 

Series 12 (amaryllis). 28 

Series 13 (hyacinths) 28 

Series 14 (hyacinths) . 29 

Series 15 (onions) ._ 30 

Series 16 (hyacinths) 30 

Series 17 (hyacinths) 31 

Series 18 (plunge experiment) 82 

Inoculations of 1899 ., 33 

Series 19 (hyacinths) 33 

Remarks on pathogenesis . 33 

Morphology of the parasite _ 36 

Size and shape 36 

Motility 37 

Zoogloeae 38 

Spore formation 39 

Involution forms 39 

Behavior toward stains 40 

Synopsis of characters 40 

Remarks on relationship 42 

Explanation of illustrations 44 

I 



ILLUSTRATIONS 



Plate. 

Page. 

Plate I. Pseudomonas; hyacinthi ( Wakker ) Erw. Sm 46 

Text figures. 

Fig. 1. Diseased scale of hyacintli ...,. 22 

2. Inoculated leaf of hyacinth ... 23 

3. Culture of Pseudomonas hyacinthi on slant 30 per cent cane-sugar 

agar, showing '• shagreen"' surface . ..._.. 38 

4. Slightly magnified diagrammatic views of slime of Ps. hyacinthi on 

sweet potato, showing ' ' shagreen '" surface 38 

5. Typical behavior of Ps. hijacinthi in fermentation tubes containing 

peptone water, or peptonized beef bouillon, with addition of vari- 
ous sugars and other carbohydrates 41 

6. Ps. hyacinthi growing in strongly alkaline (0) gelatin with 10 per 

cent cane sugar. No liquefaction. The surface curves are due to 

the very gradual drying out of the gelatin 42 

8 



WAKKRR'S HYACINTH GERM, 

Pseudovionas hyacinthi (Wakker). 



HISTORICAL. 



Dr. J. H. Wakker published five papers on the hyacinth germ 
between 1883 and 1888. His studies attracted wide attention because 
he was one of the earliest investigators in the field of plant bacteriol- 
ogy in a time of general skepticism and uncertainty, and also because 
of the great care with which he seemed to have worked out his results. 
Since the conclusion of Dr. Wakker's studies, which were begun in 
1880, no bacteriologist or plant pathologist seems to have given any 
personal attention to the disease. Several pathologists have written 
about it or referred to it,' but nothing of any value has been added, 
and some of the comments have served only to throw doubt on the 
original inquiry. 

In reading Dr. Wakker's papers for the purpose of making an 
abstract, I was at once struck with the need of a reinvestigation of 
the subject. This seemed necessary for two reasons: (1) Methods of 
isolation were not then as well understood as at present, and most of 
Wakker's successful infections seem to have been direct ones; (2) the 
germ is so imperfectly described that, excluding the test of patho- 
genesis, the identification of any particular organism as Bacterium 
hyacinthi Wakker would be altogether impossible. No disparage- 
ment of Dr. Wakker's beautiful studies is here intended. At the same 
time nothing perhaps better serves to illustrate the important advances 



' De Bary: Vorlesungen iiber Bacterien, Leipzig, 1885, p. 137; also 8. Auflage, 
Leipzig, 1900, p. 173. 

Sorauer: Handbuch fler Pflanzenkrankh. . 2. Auflage. 2. Theil, Berlin, 1886, p. 99. 

Kramer: Die Bakteriologie in ihren Beziehungen zur Landwirtschaft, etc. 
Erster Theil. Wien. 1890. p. 145. 

Comes: Crittogamia Agrai-ia. Napoli, 1891, p. 510. 

Ludwig: Lehrbnch der niederen Kryptogamen. SUittgart, 1892, p. 90, 

Tubeuf : Pflaiizenkr. durcii kryptogame Parasiteii vernrsacht. Berlin. 1895, p. 550. 

Prillieux: Maladies des Plantes agricoles et des Arbres frui tiers et forc^stiers 
causees par des parasites vegetaux, Paris. 1895. Tome I, p. 22. 

Frank: Die Krankheiten der Pflanzen, 2. Auflage, 2. Band, Breslau, 1890, p. 23. 

Migulaj System dei- Baketrien, 1. Bd.. Jena, 1897, ]). 320. 

Hartig: Lehrbuch der Pflanzenkraiikheiten, 3. Auflage. Berlin. 1900, p. 209. 

9 



10 

which have been made in the technique of bacteriology than a perusal 
of the best earh' papers. 

It is not unlikely that the additions which I shall make will also be 
insufficient, exclusive of the pathogenic test, to differentiate this 
germ ten or twenty years hence, but they will at least help toward 
definitely settling the group to which it belongs. Readers who wish 
merely a summary of Dr. Wakker's conclusions will find it in my 
critical review already cited, and those who wish to read the original 
papers will find the necessary references in the same paper. ^ Inas- 
much as that review is very full and readily accessible, I may be 
excused from going over the ground again in this place. 

SOURCE OF MATERIAL. 

The hyacinth bulbs from which the germ that I have studied was 
isolated were said to be in the first stages of the yellow disease, and 
were sent to me in October, 1896, by Messrs. Van Meerbeck & Co., 
growers of bulbs at Hillegom, near Haarlem, Netherlands. The bulbs 
were sound externally. They had been " visited," ^ and some of the 
vascular bundles of the inner scales were yellow, broken down, gummy, 
and full of bacteria. Penicillium was also present in places. No 
difficulty was experienced in isolating a yellow micro-organism from 
the broken down bundles of one of these bulbs, and subsequently the 
same germ was isolated from another bulb of the same lot. By plant- 
ing a third bulb the disease was also obtained tlie following year in a 
daughter bulb. I have now cultivated this organism over four years 
in hundreds of cultures on a great variety of media, and have 
also obtained very satisfactory infections— infections so exactly like 
those described by Dr. Wakker that there can be no doubt either as 
to the nature of the organism with which I have worked or as to the 
substantial accuracy of Dr. Wakker's conclusions respecting its patho- 
genic properties. 

INOCULATIONS OF 1897. 
SERIES 1 (HYACINTHS). 

The first set of inoculations was made February 16, 1897, from a 
pure beef-broth culture. Eight vigorous hyacinths were inoculated. 
They were all of one variety, a robust, single-flowered, deep-blue sort 
(name unknown). The plants were just coming into blossom and 
were the picture of health, six of the eight bulbs being large and well- 
stocked with food, and the other two smaller daughter bulbs. Part 
of the inoculations were by means of ordinary needle punctures and 

1 The Bacterial Diseases of Plants: A Critical Review of the Present State of 
our Knowledge, Parts III and IV, The American Nati(ralist, October and Novem- 
ber, 1896. pp. 797, 912. 

2 Removal of the top of the bulb with a sharp knife for purposes of inspection 
is called •• visiting." This is done after the bulbs are dug. 



11 

the rest by means of a hypodermic syringe, the results being the same, 
except that the symptoms appeared sooner when a large nnmber of 
germs were inserted. All of the inocnlations were made in the middle 
or terminal parts of healthy leaves, with one exception, in which case 
the germs were inserted into the upper part of a flower shaft before 
the buds opened. 

Much to my surprise, the progress of the disease was very slow, 
exactlj^ as described by Dr. Wakker, and the striping down of the 
disease was restricted in most cases to long, narrow areas, with healthy 
green tissue to either side. In case of the hypodermic injections, 
however, a width of three to eight or more vascular bundles was 
involved, i. e., as much breadth of tissue as appeared water-soaked 
after the injection, but not much more. Even when a great quantity 
of germs Avas injected (0.5 cc. or more of a fluid culture) the disease 
did not appear immediatel}^, develop rapidly, or cause widespread 
infection of the bulbs. 

To show how closely my results tally with those obtained by Dr. 
Wakker,^ I will here set down the course of the disease in each of the 
eight plants first inoculated. 



' See Contributions k la pathologie vegetale, I, La maladie du jaune, ou maladie 
nouvelle des jacinthes, causes par le Bacterium Hyaciiithi, Archives neerlandaises 
des sci. ex. et naturelles. Tome XXIII, pp. 18-20. 



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17 

These bulbs were planted close together in a shallow pot of sandy 
earth, only the lower half of each bulb being buried. The plants 
were on a bench in a greenhouse, where there was an abundance of 
light and air and where they received water from time to time as 
required. The external symptoms were so slight and progressed so 
slowly that no record was kept after March 22. The plants were, 
however, under almost daily observation during April and May. 
The}^ made a vigorous growth for two months or more after flowering 
time, but as the warm weather of summer came on the leaves gradu- 
ally dried out and died from the top down, and, with the exception of 
the bases, were pretty uniformly shriveled by the middle of June. 
This shriveling was not, however, the result of the disease. In fact, 
so little increase of symptoms was observed in April and Maj^ that 
when the bulbs were cut open (June 23) it was with no expectation 
that any diseased places would be found. That some of the leaf 
inoculations did dry out and fail after starting was evident, but enoiigh 
succeeded to place the success of the experiment beyond doubt, one 
or more bundles in the bulb scales of each one of the 8 different 
plants being yellow, broken down, and full of bacteria (see PI. I, fig. 1). 

None of these plants became wet-rotten or bad-smelling as a result 
of the bacterial infection, the symptoms being wholly unlike those 
obtained by Dr. Heinz with his Bacillus hyacinthi-septiciis. So far 
as observed the diseased plants had no odor whatever; certainlj^ no 
pronounced odor. No mycelium was present in any of these yellow, 
broken-down bundles, or in any of the bulb scales, and in most cases 
no micro-organism of any sort was present except the one which had 
been introduced into the leaves (and scape) in the preceding Febru- 
ary; i. e., more than four months before and at a distance of from 15 
to 25 cm. from the bulbs. No animal parasites were observed. 

Nearly all the scales of these eight bulbs were still entirely sound, 
but from the condition of the plateau, when the germs had penetrated 
that far, it was evident that a general infection of the scales and a 
more or less complete destruction of the bulbs would have been only 
a matter of time. Even in the attacked scales the greater part of the 
tissue was still sound. 

Previous to making these inoculations I was inclined to attribute 
the slow progr(!ss of the disease in Dr. Wakker's inoculated plants to 
the low temperature at which his plants were kejit, or else to his hav- 
ing used cultures containing very few living germs. ^ Having myself 
inoculated from a culture in prime condition for experimental pur- 
poses (i. e., swarming with motile rods), having in nearly one-half the 
cases inserted great numbers (that is, thousands) of the germs, hav- 



' From my critical review, published in 1896, it will be seen that even then I was 
inclined to regard Dr. Wakker's statements respecting pathogenesis as substan- 
tially correct, and my subseciueut studies have fully contirnied this view. 
8970— No. 20—00 2 



18 

ing kept the plants at considerably higher temperatnres (20° to 30° C), 
and yet having obtained the same results as Dr. Wakker, I am forced 
to the conclusion that the organism is a rather feeble parasite and that 
the slowness of its progress in the plant is due to natural causes, tne 
discussion of which I will undertake later on. 

SERIES 2 (onion). 

On December 13 six shoots of an onion (Allium cepa) were inocu- 
lated with bright yellow slime from a potato culture (tube 12, Decem- 
ber 4), by means of numerous needle punctures. 

Result: The plant developed no leaf symptoms, and when the four 
bulbs (all from one root) were dug and examined in June, 1898, there 
was no trace of yellow bundles or other indication of disease. 

NATURAL INFECTION OF A DAUGHTER BULB. 

In April, 1897, a diseased bulb was potted and placed in the hot- 
house. This was the last remaining bulb of those received from 
Holland the preceding fall, the rest having been cut for study or 
having fallen to pieces in the dry air of the laboratory, to which they 
had been exposed for six months. The planted bulb did not sprout 
for a long time, but finally developed some feeble leaves. No par- 
ticular attention was given to it during the summer and fall, but in 
midwinter I noticed that the leaves were dying at the top and were 
crooked — i. e., came up exclusively from one side of the bulb and 
curved over toward the other side. In February, 1898, the plant was 
knocked out of the pot and examined. The bulb which I had planted 
was completely decayed. All of the leaves were from a small daugh- 
ter bulb, which was not present, or at least not visible, when the 
mother bulb was planted. This bulb was one-sided, had only a few 
leaves, and these were dying at the top. There was no wet rot of the 
leaves or bulb and externally the bulb was sound. On cutting it open 
more than forty vascular bundles in the otherwise sound white scales 
were found to be bright j^ellow, and a careful microscopic examina- 
tion showed them to be full of the hyacinth germ. These yellow 
bundles were in eight different scales. That the daughter bulb had 
contracted the disease from the mother bulb which I planted was 
evident (1) from the fact that there was no other visible source of 
infection — i. e., this bulb was planted in good soil, in which hyacinths 
had never grown and was the only hyacinth in the gi-eenhouse; (2) 
from the fact that the plateau was the most badly affected part of the 
bulb; and (3) from the fact that the scales seemed to have been 
infected from below up, the yellow slime in more than two-thirds of 
the affected bundles being visible to the naked eye only in the lower 
half of the scales, whereas in bulbs which became diseased as the 
result of my leaf infections the upper half of the scales (so far as 
examined) was always the first to show the symptoms. Probably the 



19 

leaves curved toward the decayed mother bulb from whicli the infec- 
tion was received, as in case of one described by Dr. Wakker, but 
this I neglected to determine. 

INOCULATIONS OF 1898, 

The following year these experiments were rei>eated. All the plants 
were in the same greenhouse. The night temjperature of the house 
for a month or two, during which symptoms were slowly extending in 
the hyacinth leaves, was 10° to 18° C. ; the day temperature was 21° 
to 31° C. Subsequently, during May and June, the temperature 
fluctuated more, and some of the time it was considerably higher, 
especially in the daytime — that is, 10° to 20° C. by night and 30° to 
46° C. by day. On quite a good many days during this period the 
air temperature for some hours ranged from 35° to 40° C. — i. e., too high 
for the growth of tliis organism, as shown by maximum temperature 
experim<mts, and probablj'^ high enough to have been of material aid 
to the plant in resisting the attack of the parasite. 

SERIES 3 (hyacinths). 

The third series of inoculations was made January 29. Seven 
well-grown hyacinth plants, not yet in bloom, were selected for this 
purpose, and eight uninoculated j^lants were held for comparison. 
All were inoculated from an alkaline beef-broth culture (No. 4, Jan- 
uary 25), using a hj^podermic syringe. Two were inoculated by 
means of numerous punctures into the short, unexpanded inflores- 
cence. The other five plants were inoculated in the apical i)art of 
the leaves. The leaves at this time were about one-half grown 
(10 cm. long), and three on each plant were inoculated. Including 
what was wasted, about seven to eight cc. of the cloudy fluid was used 
on the seven plants. These plants were single-flowered and of three 
sorts — flowers large white with a tinge of blue, flowers large creamy 
white, and flowers large pink with a deeper strijje down the center 
of the i)etals; names unknown. The germs used for this series of 
inoculations and all of the following were descendants of those iso- 
lated in June, 1897, from the yellow, broken-down bundles in the 
bulbs of the plants inoculated February 16 (see first series). 

Result. — Four of the check plants were destroyed by a rapid soft 
white rot. The other four were sound and free from all trace of the 
yellow disease when examined June IS. 

All of the seven inoculated plants showed distinct above-ground 
symptoms, the progress of which was slow. Three of these were 
attacked in the spring by a rapid soft white rot. In one of tliese, 
which was dug early, the unsoftened part of the bulb showed two 
yellow bundles. Tlie other four — i. e., those not attacked by tlie soft 
rot, were dug June is. Tlie bulbs wen^ souikI externally. Two 
were sound internally, so far as could be determined by the unaided 



20 

eye — i. e., the disease seemed to have died out in the parts above 
ground. In the other two there were distinct symptoms in the bulb. 
In one bulb several scales had yellow bundles, and the plateau was 
also diseased in the upper j^art ; in the other bulb the disease was 
restricted to two bundles in the upper part of one scale. 

SERIES 4 (ONIONS). 

Three onion plants {Allium cepa) were selected for this series, 
which was begun Januaiy 29, using the same culture medium and 
method of inoculation as in series 3. Each jslant was copiously 
inoculated in the aj)ex, middle, and extreme base of several leaves. 

Result. — The young and tender leaves were killed outright within 
a few days of the inoculation, with no distinct symptoms of parasit- 
ism. The older leaves developed no symptoms whatever, or only 
such as were due to the slow growth of the parasite in the immediate 
vicinity of the point of inoculation — i. e., the symptoms were entirely 
unlike those obtained by Heinz with his Bacillus hyacinthi-septicus. 
In case of half a dozen or more leaves the germ was able to hold its 
own in the inoculated tissues and finally to make a bright yellow 
growth in the parenchyma in the vicinity of the punctures. It never 
extended very far, however, and did not kill the parts in which it 
grew — at least not until after many weeks. PI. I, fig. 2, shows the 
appearance of an onion leaf in which the germ has made a slow 
growth. 

On June 22 these plants were knocked out of the pots and their 
bulbs examined. Each plant had a good top at this time and was in 
fruit. One had seven bulbs from a common root, another four, and 
the third three. xVU of these bulbs were sound. None showed any 
trace of yellow bundles. 

SERIES 5 (HYACINTHS). 

The fifth series of inoculations was made February 7, in the same 
way as the two preceding. These plants were inoculated from an 
alkaline beef broth culture (No. 1, Jan. 20), about 0.5 to 0.7 cc. of 
cloudy broth being used on each plant. Nine vigorous plants in full 
bloom Avere selected for this experiment, the variety being a single- 
flowered, pale-blue sort known as Czar Peter. Two were inoculated 
in the scape just under the inflorescence (0.3 cc. each, several punc- 
tures) and the remainder were inoculated in the apical portion of the 
leaves, three to seven leaves on each plant being selected for this 
purpose (generally three leaves).. Twenty-three plants of the same 
variety and growing in the same box were held as checks. 

Result. — Ten of the check jDlants were attacked by a soft white rot 
between Februaiy 7 and June 14, The bulbs of three of these were 
only softened a little in places when dug out and these bulbs showed 
no trace of yellow bundles. The other seven were destroyed by the 



21 

rot. None of the remaining thirteen check plants contracted any 
disease and their bulbs were sound and entirely free from yellow 
bundles when cut open and examined on June 14. 

Two of the inoculated plants were also attacked by the same rapid 
soft-rot. 1 The bulb of one, which was left undisturbed, finally 
decayed completely; that of the other was pried out February 14 to 
prevent the spread of the disease. At this time there were no foliar 
symptoms due to the inoculations. The soft-rot had just begun. It 
started at the base of two leaves in wounds accidentally made by the 
knife of the gardener in cutting away the scape. 

Distinct sjanptoms of the j^ellow disease appeared on the above- 



' This parasite, which is a rapid-growing, bad-smelling, actively-motile white 
germ, probably identical with Bacillus hyacinthi-septicus Heinz, came from the 
hot house where the bulbs were forced. The box originally contained 35 bulbs, 
the rotten. sour-sme!ling remains of 3 being discovered and pried out after its 
purchase. All the plants inoculated in 1898 came from this same forcing house 
and nearly every pot or box developed some cases of this disease. Otherwise the 
plants were very satisfactory. 

This organism was not studied critically, for lack of time, but some notes were 
made. The bacterial .slime and accompanying tissues of the host plant taken 
from the upper inner part of a diseased scape (the advancing margin of the 
decay) were examined microscopically. There was no mycelium or insect injury, 
and the innumerable bacilli were apparently all one thing. The rods were 3 to 
5 // long, and rather less than 1 /< broad, with rounded ends. They were single 
or in pairs. Very few were in motion at first (the slime was diluted with a drop 
of distilled water), but within a few minutes many became actively motile. 
This motion consisted mostly of rapid movements straight ahead, and often 
straight back in the same track, for a distance many times the length of the rod. 
Tiambling and sinuous moveuients, however, were also observed. Toward the 
close of the first hour at least one-fourth of the rods were in motion. In form, 
the motile ones were exactly like the others. While watching, I frequently saw 
stationary rods become motile and dart away. These rods stained readily in basic 
fuchsin water and in gentian violet water. This slime from the host plant gave 
a faint bad smell and was slightly sticky, stringing up 1 centimeter. Cultures 
made directly into tubes of potato from the same part of this scape, after cutting 
it open with a burning hot knife, yielded a rather slow-growing, not very copious, 
wet-looking, smooth, white slime, which was strongly alkaline and somewhat 
sticky, stringing up 1 to 3 centimeters when touched with the loop. The four 
potato cultures were alike at first and three continued to be homogeneous, while 
a pink organism appeared in the fourth tube at the end of the second day. A few 
gas bubbles also appeared in each of the tubes. 

This particular hyat-inth plant was a robust Czar Peter in full bloom, with a 
long stocky scape. The rapidity of the rot may be judged from the fact that 
when the disease was first discovered it involved only one flower. In forty-eight 
hours the scape was soft-rotten (and lopped over) from the point of infection 
nearly to the balb (10 or 15 centimeters) and also 3 to 5 centimeters above the 
point of entrance— i. e., to within a few centimeters of the top of the inflorescence. 
It was a soft wet rot, involving all of the tissues in a general collai)se of slime 
which was strongly all^aline. Another fact worthy of note is that this organism 
is (piite tolerant of acids. 

That we have here a genuine* bacterial disease of the hyacinth, worthy of careful 
study, admits of no doubt whatever. 



22 




Fig. 1. 



-Diseased scale of 
hyacinth. 



neighboring bundle. 



ground jiarts of each of the eight other inoculated plants, and pro- 
gressed slowly in the usual way. The notes upon plant No. 25, given 
below, Avill answer for all. On June 14 the bulbs of these plants were 
examined. One was free from bacterial infection so far as could be 
determined 1 )y careful cutting and microscopic examination. One was 
rotted and gone, as already noted. The six other bulbs were sound 
externally but, within, each one showed distinct symi)toms of Dr. 
Wakkers disease^-i. e., there were few to many yellow bundles full of 

bacteria in otherwise sound scales. In most 
cases the plateau was also involved. Generally 
the yellow disease was closely restricted to indi- 
vidual bundles, the parenchjnna between them 
being sound. In several cases, however, small 
bacterial pockets had formed in the paren- 
ch^^ma around a bundle; in one case all of the 
parenchj^ma between two neighboring bundles 
was yellow ; rarely, some of the smaller anasto- 
mosing veins would be yellowed nearly to a 
All of these features are shown in fig. 1 (from 
plant Ko. 20). In no case was there observed an 3' rupture of the epi- 
dermis of the affected scales or flow of the yellow slime between the 
scales, the bulbs being examined too early for this stage of the disease. 

Notes on No. 25. — Inoculated February 7 in the apical part of 5 leaves by means 
of a hypodermic syringe, suffused stripes resulting in each case. 

February 14. Leaves 12.5 centimeters long. No symptoms. The suffused stripes 
due to the injection soon disappeared. The absence of symi)toms is surprising, con- 
sidering the quantity of germs inserted and the time that has elapsed (seven days). 

March 1. Each of the five leaves now shows a yellow stripe down its center. 
The breadth of these stripes is 3 to 6 mm. A few of them extend from near the 
tip of the leaf almost to its base. Below the shorter stripes is a line of narrow, 
interrupted, water-soaked spots. To either side of thj stripes the leaves are green 
and normal in appearance. On one leaf only has any tissue shriveled, and that to 
but a small e-ctent. The parenchymatic tissue in the stripes has become translu- 
cent, while the parallel main bundles begin to be feebly browned. The greater 
part of each leaf is still healthy, the symptoms being confined to the vicinity of 
the injected parts. The sym:)toms a week ago (fourteenth day) were very slight. 

April 30. A marked increase of symptoms. The stripes now extend one-half 
way down, two-thirds down, and entirely down to the base of the leaf. The parts 
which were striped on March 1 are now dead and diaphanous or brownish. The 
deepest brown is in the larger vascular bundles, and is feeble in comparison with 
the brown veining of the cabbage produced by Pa. eampestris. At the ba-e of 
these dead stripes the disease continues in the form of water-soaked stripes, which 
are more or less interrupted, i. e., the surface symptoms disappear and reappear 
a few millimeters lower. To either side of the dead, brown stripes there is a nar- 
row yellow line beyond which the tissue is green and normal in appearance. Two 
of the leaves have collapsed and dried out at the tip (1 cm. and 6 cm.). The slow 
sidewise movement of the disease is very marked, and becomes astonishing when 
we consider the enormous number of germs o.-iginally inserted into these leaves. 
On one of these leaves there is an interrupted, water-soaked stripe in the narrow 
yellow border, indicating a recent slight sidewise movement of the parasites. All 
of these fcymptoms are shown in fig. 2. 



23 




June 14. The leaves are dead; the bulb is sound externally. On sectioning, the 
interior of the plateau was found to be diseased and there were also twenty -two 
yellow bundles distributed through eleven different scales. These yellow bundles 
were partially broken down and full of bacterial slime. That many of them were 
tertiary infections (from the inoculated leaves by way of the plateau) was very 
plain, since the yellow slime, while always distinct in the basal part of the bundle 
next to the plateau, frequently became less abundant or disappeared altogether in 
the middle or upper part of the scale. The greater part of the bulb was still 
sound. No mycelium was present and there were no injuries from animals. 

SERIES 6 (ROMAN HYACINTHS). 

Four Roman hyacintlis (Hyacinthus aTbulus) were selected for this 
series, wliicli A^as started Feljruaiy 7. The phints were line speci- 
mens, in full bloom. Two of them were inoculated 
in the middle part of tlie scapes (three scapes on each 
plant) and the other two in the apical part of the leaves 
(four leaves on one ]3lant and seven leaves on the other) . 
The infectious material, alkaline beef-broth cultures 
(Nos. 1 and 4, January 29), Avas put in l)y means of a 
hypodermic syringe. Two plants in the same pot were 
held as checks. 

j^esif?/. —The six inoculated scapes gradually shriv- 
eled, but with no symptoms clearly attributable to the 
action of the germs. Each of the eleven inoculated 
leaves slowly developed narrow stripes corresponding 
to the parts of the leaf suffused at the time of the 
inoculation. These stripes did not appear until after 
the seventh day. There was very little sidewise exten- 
sion, and tlie downward movement was very slow. At 
first tlie stripes presented a watef^soaked appearance. 
Later they were pale yellow, with brownish veins, and 
when dead and dry they were yellow-brown. No such 
stripes appeared on any of the uninoculated leaves, of 
which there were many. On June 15, Avhen all the 
leaves were dead and gone, the bulbs were removed 
from the i)ot and examined. Each had formed several 
to many daughter bulbs, but neither in these nor in 
the mother bulbs was there any trace of the yellow 
disease. All were sound so far as could be determined by the 
unaided eye. 

SERIES 7 (HYACINTHS). 

The seventh series of inoculations was made February 7, in the 
same manner as the preceding. Vox tliis experiment I selected sixteen 
vigorous plants of the single, white-flowered liaron van Tujdl, holding 
fifteen plants of the sanu3 variety growing in the same box as checks. 
The plants were in full bloom. Each bore five to seven good leaves, 
three of which were inoculated in the apical part. Each plant received 



Fig. 2.— Inocu- 
lated leaf of hy- 
acinth No. 25. 



24 

from 0.5 to 0.7 co. of the cloucly alkaline beef broth culture (No. 4, 
Jan. 20). 

Result. — Thirty-five bulbs had been planted in this box. Two were 
rotted and gone when it was purchased, and a rapid soft rot devel- 
oped on the scapes of two others a few days later, so that only thirty- 
one healthy plants remained at the date of inoculation. The fifteen 
plants held as checks never developed any leaf sj^mptoms comparable 
to those on the inoculated plants, and fourteen of the bulbs were 
entirely sound when dug and examined June 16. The other bulb was 
free from the yellow disease, but was just beginning to succumb to 
the soft white rot (the extreme top of the bulb). 

Every one of the fortj^-eight inoculated leaves (sixteen plants) 
developed symptoms of the yellow disease. These symptoms 
appeared for the most part only after fifteen to thirty days, and the 
progress of the disease was xery slow, although distinctly visible for 
a month or two, i. e., until the hot weather set in, when the disease 
seemed to die out in many leaves. On June 16, when the bulbs were 
dug and examined, two Avere soft-rotted, with the exception of a few 
outer scales, which showed no trace of the yellow disease. The other 
fourteen plants had better-preserved leaves than the corresponding 
plants of Czar Peter (series 5). Ten of the bulbs were entirely free 
from symptoms of the yellow disease and perfecth'^ sound so far as 
could be determined by the unaided eye. The other four were 
attacked by the yellow disease, but not extensively, and for the most 
part only in those scales which bore the inoculated leaves. All of 
this variety took the disease less rapidly than the Czar Peter. The 
plants were very carefully examined from time to time and notes 
made on the condition of each one, the two sets of notes which follow 
being fairly illustrative of the whole lot. 

Notes on plant No. 4(9.— Inoculated February 7 in three leaves. 

February 14. No symptoms. The plant has five leaves which are now 17.5 cm. 
high. 

March 1. One leaf only shows any decided symptoms. These consist of a stripe 
in the upper central part of the leaf (the inoculated part) which is yellow in the 
wider iipper part of the stripe and water-soaked in the lower 3 to 4 cm. The 
length of the stripe is 9 cm., the breadth is 3 to 3 mm. in the upper part and only 
1 mm. in the lower, water-soaked part. Symptoms in the other inoculated leaves 
are restricted to the vicinity of the needle puncture, and consist of a slight water- 
soaked appearance in the form of narrow, short, interrr.pted lines. All of this 
white variety have taken the disease less rapidly than the Czar Peter. 

March 30. There has been a distinct progress of symptoms. On the first leaf 
there is a stripe of yellow-brown, dry tissue 3 mm. wide and 7 cm. long. On the 
second leaf there is a stripe 3 to 5 mm. wide and 3 cm. long, which is yellow with 
a dry, brown center. On the third leaf the stripe is ~) mm. wide and 3 cm. long. 
Most of this is simply yellow, but the central part is dry and brownish. Below 
the well-defined stripe are narrow, short, interrupted water-soaked lines on a green 
background. These water-soaked lines are separated from the older yellow- brown 
stripeby 3 to 4 cm. of healthy-looking tissue. This appearance must be due to 
germs which have broken out of the bundles and grown or diffused into the par- 



25 

enchyma in these particular places, or which have so destroyed the tissues as to 
allow the juices to flow out. The greater part of the three inoculated leaves and 
all of the other two leaves are sound. The leaves are now about 30 cm. long. The 
opinion of March 1 as to the greater resistance of this variety is certainly confirmed 
by the observations made to-day. 

June 16. The basal 15 era. of two of the inoculated leaves is sound. On the third 
it is sound, except for a narrow, interrupted, water-soaked stripe which extends to 
within 5 cm. of the bulb. The bulb was carefully sectioned at various levels from 
the base of the plateau to the top of the scales, but there was no trace of yellow 
bundles or any other symptom of disease. Of course it does not follow that some 
of these bacteria had not gained entrance to the underground parts or that six 
months later this bulb would not have been diseased. Indeed, E believe it would 
have been. 

Noteii on plant No. 4C.— Inoculated in apical part of three leaves on Februry 7. 

February 14. No symptoms. The plant has five leaves. ir..5 cm. long. 

March 1. Long, narrow, water-soaked lines have appeared in the injected part 
of two of the inoculated leaves. As yet there is no yellowing. The third leaf 
shows no symptoms. 

March 30. There are now distinct symptoms on each of the inoculated leaves. 
The stripe on the first leaf is .5 cm. long and 3 to 5 mm. wide. It is brown in the 
upper (widest) part, where the bulk of the injected fluid must have lodged. The 
tip of the second leaf is dry and brown (3 cm. ) , and in tlie middle of the leaf from 
this point down for a distance of 8 cm. the symptoms continue in the form of nar- 
row, interrupted, water-soaked stripes. On the third leaf the yellow stripe is 
5 mm. broad in its upper part and 1 to 2 mm. wide in the middle and lower part. 
Farther down the stripe is composed of narrow, interrupted, water-soaked lines 
on a green background. No part of the stripe is brown. The rest of the plant is 
normal. Here, as in No. 45, the symptoms on one leaf did not develop until after 
twenty-one days, and from the present appearance probably not until more than 
thirty days had passed. This is very remarkable, considering the number of 
germs used, and can be explained only on the supposition that most of them have 
been destroyed in the plant or, if not killed outright, have been able to overcome 
retarding influences only very slowly. 

June 16. The basal 5 to 15 cm. of each leaf is sound externally; the rest is dead 
and dry. The bulb is sound externally. On cutting open, one scale only was 
visibly afifected. This scale bore one of the inoculated leaves, and the visible 
symptoms were restricted to the upper third of the bulb and to one bundle. The 
p'ateau and all the other scales were free from symptoms, but probably a careful 
microscopic examination would have shown the beginning of disease in other 
bundles of this scale. 

SERIES 8 (HYACINTHS). 

The eighth series of inoculations was made February 11 in the same 
manner as the preceding. For this experiment two pbxnts of the variety 
known as Gertrude were selected, and two plants of the same variety, 
in the same pot, were hekl for comparison. This variety is a deep- 
rose, single-flowered, vigorous-growing sort. The plants were in full 
bloom. One had eight leaves, the other nine. Three leaves on each 
plant were inoculated near the apex from the well-clouded beef-broth 
culture (No. 0, Feb. 5), 0.3 cc. being injected into each leaf. These 
leaves were 10 to 12 cm. long. The needle was inserted about 2.5 cm. 
from the apex of the leaf, and the narrow, su (fused (water-soaked) 
stripe which appeared immediately after the injection of the fluid often 
extended nearly to the base of the leaf. 



26 

j^^s^i^/. —Characteristic symptoms of the yellow disease were visible 
on each of the iiiocvilated leaves as early as February 14. At first the 
disease progressed much more rapidly than on any other variety. 
Later its spread was slow. The stripes in the inoculated leaves 
extended downward slowly untiV the end of March, at which date 
there were symptoms on no otlier leaves. About this time both of 
the inoculated plants and the two check plants were attacked and 
destroyed b}^ the rapid soft white rot. 

SERIES 9 (hyacinths). 

The ninth series of inoculations was made February 11 from the same 
culture and in tlie same manner as the preceding, i. e., 0.3 cc. of the 
cloudy fluid was injected into each leaf. For this experiment I 
selected two healthy plants of a single-flowered, j)ale-rose variety 
known as Gigantea. Six plants of the same varietj^ in the same pot 
were held as checks. The plants were in full bloom. Each i^lant 
had four to five leaves, three on each plant being inoculated near 
the apex. At this time the leaves were 9 to 11 cm. long. 

Result. — On February 17 there were no symptoms on either plant. 
By March 1 there were pronounced stripes on four of the six inocu- 
lated leaves. The other two leaves (seventeenth day) showed no symp- 
toms. These stripes were 2 to 3 mm. wide and 6 cm. long, extending 
down the middle of the leaf. The older portions of these stripes were 
dull yellow and semi-transparent, with pale brown bundles. Above and 
below this portion the striping continued in the form of water-soaked 
spots. To either side of these narrow stripes the leaf was healthy. 
The appearance of one inoculated leaf from each plant (March 5) is 
shown in PL I, figs. 3 and 4. Later, both of these plants Avere spoiled 
by the rapid soft white rot. None of the uninoculated leaves ever 
showed any symptoms of the yellow disease. Two of the check plants 
developed the rapid soft rot and were dug out soon after the experi- 
ment began. In both the rot began in the blossoms, and in one it was 
still confined to a single flower and a small portion of the adjacent 
scape when discovered. The other four check plants were dug and 
examined June 17. All were soft-rotted at the heart, but in the scales 
which remained in condition to be examined there were no yellow 
bundles. 

SERIES 10 (hyacinths). 

The tenth series of inoculations was made February 11 from the 
same culture as the preceding. For this experiment another pot of 
Gertrude was selected. The plants were in full bloom and very 
healthy. Four were inoculated and four others in the same pot were 
held for comparison. Each of the plants bore eight to ten leaves. 
Two were inoculated in the apical portion of the leaves (three leaves 
on each plant) by means of a hypodermic syringe, 0.3 cc. of the cul- 
ture being put into each leaf. The other two were inoculated in the 
same way in the scape, just under the truss of flowers, several punc- 



27 

tiires being made. One of these scapes received 0.3 cc. of the cloudy 
brotli and the other 0.6 ec. 

Result. — Four of the six inoculated leaves showed distinct symp- 
toms on February 14. No stripes were visible on the other two until 
after February 17, and they were slight on March 1, consisting merelj^ 
of some narrow, parallel, water-soaked lines. On March 1 two of 
the other four leaves were shriveled to the base, and a third was 
shriveled halfway down and showed water-soaked places farther 
down. Neither of the plants inoculated in the scape showed any 
sjnnptoms until after February 17, all of the flowers wilting normally. 
On March 1 the scape which received 0.3 cc. showed one very narrow, 
short, water-soaked stripe in the npper i^art under the shriveled flow- 
ers, and at the end of this niontli some of the leaves began to be 
3^ellowish-green between the vascular bundles as if disturbed in their 
nutrition. The scape which received 0.(5 cc. showed on March 1 two 
or three narrow, short, water-soaked lines below the shriveled flow- 
ers. At the end of this month the scape was wholly shriveled and 
the leaves dead at the top (upper 3 to 6 cm.). On June 17, when the 
bulbs w^ere dug for examination, all were spoiled by the soft rot. 

The leaves of the check i)lants never developed any symptoms of 
the yellow disease. On June 17, when the bull)s were dug for exam- 
ination, all of them were soft-rotted at the heart, but none of them 
showed any trace of yellow bundles. 

SEmES 11 (CABBAGE). 

The eleventh series of inoculations was made on young cabbage 
plants in active growth. They were inoculated Februarj^ 11 from the 
same culture as the preceding (No. G, February' 5). On each of two 
plants the germs were forced into several parts of two leaf blades by 
means of the syringe, and on each of the same leaf blades numerous 
delicate punctures were made with the tip of the needle and the fluid 
bearing the germs was carefully rubbed in and not allowed to dry 
immediately. To prevent any injurious action of sunshine or of dry 
air large drops of the culture were Anally put on the punctured parts 
and sheltered from the direct action of the light and of air currents 
until nightfall. The germ-laden fluid was forced into 2 petioles of a 
third plant, so that they showed long, suffused streaks, while here and 
there the fluid oozed through the epidermis in many very tiny drops. 
The blade of a third leaf on this plant was punctured, inoculated, 
rubbed, covered with fluid, and sheltered as described above. 

Result. — After some days the two injected petioles split open, but 
no otlier symptoms appeared, not even in the immediate vicinity of 
the injected and punctured parts. The plants were under observ^a- 
tion nearly four months, and differed in no respect from the check 
plants. Inoculations of such plants with Pseudonionas cnmpestris 
led to very different results, as I have shown elsewhere.^ 

'See Centralb. f. Bakt., 2. Abt. Bd. Ill, July, 1897, p. 284. 



28 

SERIES 12 (AMARYLLIS). 

The twelfth series of inoculations was made February 11 on the 
well-grown leaves of AinarylUs atamasco. Two plants, not j^et show- 
ing any flower shoots, were selected for this purpose, and three healthy 
plants in the same pot were held as checks. Two leaves were selected 
on each plant and 0.3 cc. of the cloudy broth culture (No. 6, February 
3) was injected into each of two places on each leaf. 

Result. — The sjnuptoms developed verj^ slowly as feeble yellowish 
stripes, confined to the parts originally suffused. Subsequently in the 
striped part the plants produced, as is their wont when injured, a red 
pigment. On March 1 this red pigmentation was quite distinct in each 
one of the eight inoculations. On March 31 it was more pronounced, 
occurring mostly in the form of interrupted red streaks on a green 
background. These were visible on one leaf for 10 cm. below one of 
the needle punctures and for 12 cm. above the other. On another 
leaf the red dots and stripes extended 7 cm. above a needle puncture 
and 9 cm. below it. At this point there were more than 100 red dots, 
each less than 0.5 mm. in diameter. These red spots were in parallel 
rows over vascular bundles and not in the parenchyma between the 
bundles. In the widest part of the stripe four vascular bundles had 
these red spots over them. In the oldest and worst stained part of the 
stripe (near the puncture) the red stain also involved the parenchyma 
between the bundles. After this date the disease made only very slow 
progress. On June 18 the bulbs were knocked out of the pot, sec- 
tioned at many levels, and carefully examined. All were entirely 
free from any trace of yellow bundles and j)erfectly sound. 

SERIES 13 (HYACINTHS). 

The thirteenth series of inoculations was undertaken February 12, 3 
p. m., to determine whether infections might not be secured through 
the blossoms. For this purpose I selected four single, blue-flowered, 
healthy i)lants of Baron van Tuyll, four plants of the same variety 
and in the same pot being held as checks. All were in full bloom. Six 
flowers on each of the four plants were inoculated by putting a big 
drop of cloudy beef broth (No. 11, February 3) gently into the throat 
of each one without in any way touching the flower wi^h the needle 
of the hypodermic syringe. The pot and the earth on which it stood 
were heavih' watered and then covered with a large bell jar. This jar 
was removed February 14, at noon, when the drops had disappeared. 
Bees had access to the hothouse and visited these plants freely all 
day, but for the most part they carefully avoided the inoculated 
flowers. In one instance, however, I saw a bee enter an inoculated 
flower. Frequently they passed in front of such flowers and occa- 
sionally prepared to enter and then suddenly withdrew and selected 
uninoculated flowers. 

The throat of the contracted perianth did not wet readily, and so 



29 



much uncertainty was felt as to likelihood of the infection reaching 
the nectaries that this series and the following one were repeated. 
(See series 16 and 17.) 

Eesult — These plants were examined March 2 and again March 31. 
On three of them there were no symptoms whatever and on the fourth 
there were symptoms of ill health, but none clearly attributable to the 
inoculation. (The bulb of this plant subsequently rotted.) On June 
18, when these plants were next examined, one of the l)ulbs had soft- 
rotted, two appeared to be sound, and the fourth was affected with the 
yellow disease. My notes on this particular plant are as follows- 

Notes on plant No. 6.?.— February 12, 3 p. m. Inoculated six flowers. 

February 14, noon. Bell jar removed. The fluid has disappeared from the 
flowers. 

February 17. The flowers are still in good condition. The inoculated ones have 
not shriveled or fallen off. 

March 2. The scape is green and healthy to its tip. There is no evidence of any 
infection. The flowers have shriveled, but it is a normal withering. The leaves 
are sound. They are .JO cm. long and the scape is somewhat taller. 

March 31. The leaves are healthy and there is no sign of yellowing, shriveling, 
or down-striping in the scape, which is still green and perfect to its summit. 

June 18. Leaves dead, bulb sound externally except for a slight dry rot in the 
extreme outer part of the plateau, which entirely disappears 1 mm. in. Consid- 
erably farther up, the bulb shows distinct symptoms of the yellow disease, which 
increase in the plateau from below upward. In the upper part of the plateau 
there are quite a number of yellow bundles and several small cavities full of yel- 
low bacteria. Near the plateau twenty-three vascular bundles in eleven scales are 
yellowed and more or less broken down by the bacterial slime. Farther up (near 
the top of the bulb) only sixteen bundles are visibly affected. These are close 
together on one side of the bulb in eight scales (Plate I, fig. 5). One scale of this 
bulb was photographed by itself and is shown in Plate I, fig. 6. 

None of the check plants showed any symptoms of this disease. On June 18 
three of them were entirely sound, while the fourth was partly destroyed by the 
soft white rot. 

Infection of a daughter bidh.—On the flat side of the bulb (shown 
in Plate I, fig. 5), and still attached to it by a common plateau, was 
a good-sized daughter bulb. This was also diseased, but only where 
it Joined the mother bulb. In the base of its plateau there were 20 
vascular bundles full of the yellow slime, but the upper part of the 
plateau showed no symptoms and all of its scales were sound. 

SERIES 14 (HYACINTHS). 

This series was begun February 12 and was in all respects a dupli- 
(;ate of the thirteenth, except that a large single, white-flowered variety, 
known as Mont Blanc, was used. Six flowers on each of five plants 
were inoculated and three plants in the same pot were held for com- 
parison. 

Residt.—\J-p to March 31, at which date the observations ceased, 
there were no symptoms on any of those plants whicli could be defi- 
uitely ascribed to the inoculations. On June 17, wlien tiie bulbs were 



30 

dug and examined, the three check plants were entirely sound. Three 
of the inoculated plants were also sound, or at least appeared so to 
the unaided eye. The bulbs of the two other plants were sound 
externally, but on sectioning them they showed unmistakable symp- 
toms of the yellow disease. One was slightly affected in two scales. 
The other was more seriously diseased, as will be seen from the fol- 
lowing account of it: 

Notes on plant No. 67. — February 12, 3 p. m. Inoculated six flowers. 

February 14, noon. Removed the bell jar. The heart of the inoculated flowers 
is still moist. 

February IT. The flowers begin to shrivel. The inoculated ones are holding 
up best. 

March '2. The flowers have withered. The scape is large and 80 cm. long. 
Its upper 2 cm. is yellow and shriveling, but there are no symptoms attributable 
to the inoculations. The rest of the scape is green and turgid. The leaves are 20 
cm. long and are healthy. 

March 81. The scape has dry-shriveled and all of the leaves are drying out at 
the tip (3 to 10 cm. j. The plant looks bad, but there are no stripes on the leaves, 
not even at their extreme base. 

June 17. Leaves dead, bulb sound externally. On cutting, twenty-two yellow 
bundles were found in the upper part of the white and otherwise sound plateau. 
The infected bundles were all on one side of the bulb and were beautifully distinct, 
as in case of No. 63. In the upper part of the bulb eleven bundles in four scales 
were visibly affected, the j'ellow slime oozing from the cut surface. Lower down 
(near the plateau) a larger number of bundles were yellow, and one other scale 
was involved (one bundle, in which the yellow disappeared about halfwaj- up). 
The extreme base of the plateau was sound, and. as in No. 63, the progi-ess of the 
infection was clearly from the scape to the vessels of the plateau and from the 
latter to the scales. There was no soft white rot. 

SERIES 15 (ONIONS). 

The fifteenth series of inoculations was made February 12 on Allium 
cepa. Four well-grown onion plants not yet in bloom were selected 
for this purpose. The inoculations were by means of a hypodermic 
sja'inge, using the well-clouded beef broth in tube Xo. 11 (February 4). 
About 2 cc. was injected into one plant, numerous punctures being 
made into old and young leaves. Three leaves were selected on each 
of two other plants and 0. 3 cc. was injected into the base of each one. 
Ilie fourth plant was inoculated in the same way, 0.3 cc. being injected 
into the base of each of four leaves. 

Result. — On March 2 the inoculated leaves, in whole or in part, Avere 
shriveled and white. On March 31 there were no additional symptoms. 
On June 18, when the bulbs were dug and sectioned, all were free 
from yellow bundles and entirely sound. 

SERIES 16 (hyacinths). 

The sixteenth series of inoculations was made February 16, at 11 a. m. 
Two single, white-flowered hj acinths, of the variety known as Baron 
van Tuyll, were selected for this purpose and two plants of the same 



31 

variety, and in the same pot, were iield for comparison. The interior 
of eight to ten flowers on each plant was thoronghly infected by forci- 
bly spurting- 0.2 cc. of cloudy alkaline beef broth (from tube 3, February 
10) into the throat of the perianth. Great care was taken not to spill 
any of the culture on the leaves or to wound the flowers with the tip of 
the needle. The pot was wet down thoroughly, covered with a bell jar, 
and shaded from the light. After twenty-three hours the bell jar was 
removed, the interior of the injected flowers being still moist. The 
plants were in full bloom and very thrifty. 

Result. — On March 2 one scape showed a trace of water-soak in the 
part occupied by the flowers, but there were no additional subsequent 
symptoms. On June 21 these bulbs were dug and examined. Neither 
one showed any trace of the yellow disease. The two check bulbs 
were also sound. This variety took the disease slowly in series 7. 

SERIES 17 (HYACINTHS). 

This series was in all respects a duplicate of the preceding, except 
that I used two single, blue-flowered specimens of Baron van Tuyll, 
and inoculated a third jjlant in the leaves, holding two healthy plants 
in the same pot as checks. On February 16 eight to ten flowers were 
inoculated on each plant, each receiving 0.2 cc, which was spurted into 
the depths of the perianth, where it remained in foam. Of the plant 
inoculated through the leaves, one leaf received 0.4 cc. and the other 
two leaves 0.2 cc. each. Each foliar inoculation was made well toward 
the apex of the leaf. 

Result. — On March 2 one of the two plants inoculated in the flowers 
showed distinct symptoms in the scape. These consisted of a water- 
soaked stripe beginning in the middle part of the inflorescence in one 
of the inoculated flowers. The stripe extended downward about 5 cm. 
and involved about one-third of the circumference of the scape. In 
the ujjper part of it the vascular bundles were feebly browned (PL I, 
fig. 7). The disease moved downward rapidly in the scape, and on 
Mar(;h 31 the soft white rot having set in, the bulb was dug and exam- 
ined. There was some yellow slime in the plateau, and one bundle 
of one scale was visibly invaded by the yellow microoraanism. The 
part of the bulb recently invaded by the soft white rot was the upper 
central part, i. e., that previously injured by the growth of the inocu- 
lated organism. Up to March 31 the other i^lant developed no symp- 
toms on the scape or leaves, but the bulb was wholly decayed when 
dug and examined June 17. The cause of this decay was not then 
(letei'mi liable. 

The plant inoculated through the leaves developed beautifully typ- 
ical water-soaked stripes down the middle of each leaf. On M;irch 
2, two of these stripes were over lo cm. long. On March 31 tlic inocu- 
lated leaves were shriveled over halfway to tlie bulb. This plant 
was not again examined until ,Iune 17, when the bulb was wholly 



32 

decayed and the cause of decay not determinable. The two check 
plants never developed any above-ground symptoms, and on June 17 
the bulbs were entirely sound. 

SERIES 18 (plunge EXPERIMENT). 

The eighteenth series of inoculations was made March 10, to deter- 
mine whether infections could be obtained through the stomata. For 
this purpose I selected six pots of healthy hyacinths of the following 
varieties: Czar Peter, Gertrude, and Gigantea. All were in full 
bloom. 

The material for infection consisted of 1,000 cc, of distilled water, 
sterilized in the ordinary way after adding 10 cc. of alkaline beef 
broth. When sterile, a well-developed beef-broth culture of the hya- 
cinth germ was poured into this flask, the fluid in which was feebly 
clouded next morning and swarming with motile rods. On plating 
out, it proved to be a pure culture of the hyacinth germ. Sterile 
tumblers were filled with this fluid and the apical part of the leaves 
of selected plants were plunged into it as follows, and left twenty- 
three hours shaded from the light. On removal, the fluid adhering 
to the leaves was carefully dried in situ liy exposure to the sun before 
the plants were left, great care being taken not to infect other parts 
of the same plants or of the checks. 

Notes on plant No. SI.— One plant of Czar Peter, six leaves plunged 4 to 7 cm.; 
three healthy plants in same pot held for comparison. 

March ')0. No results. 

March 30. Plunged part of three leaves is paler green, and one of them has a 
long, narrow, brown stripe. This is IS cm. by I mm., and begins 0.5 cm. below 

the tip. 

June 21. Leaves dead, bulb sound, at least to unaided vision. All of the check 
bulbs are free from the yellow disease and all are sound, except the outer part of 
one plateau, which has soft-rotted. 

Notes on plant No. 83:— One plant of Czar Peter, four leaves plunged 4 to 8 cm. ; 
three healthy plants in the same pot held for comparison. 

March 80. No visible symptoms. 

July 1. Bulb entirely soft-rotted. One of the check plants has also entirely 
soft-rotted. The other two are sound. 

Notes on plant No. ,v./.— One plant of Gertrude, eight leaves plunged 3 to 6 cm.; 
seven healthy plants in the same pot held for comparison. 

March 30. For the last ten days one leaf has been curved downward in the 
plunged part, and this part now bears alternating narrow green and yellow stripes, 
the latter lying in the parenchyma between the bundles. One other leaf shows 
slight geotropism in the plunged part and slight yellowing in stripes between the 
bundles. The others are normal. 

July 1. The leaves are gone. The bulb has lost its center by soft rot. The 
scales which remain show no trace of yellow bundles. The checks were also 
examined. Two bulbs are sound. One is white-rotted and soft on one side, but 
shows no trace of the yellow germs. The other four are entirely soft-rotted and 

gone. 

Notes on plant No. 84.— One plant of Gertrude, eight leaves plunged 3 to 5 cm.; 
six healthy plants in the same pot held for comparison. 

March 30. No result. 



33 

June 21. Bulb rotted and gone. Of the six checks one is entirely sound, three 
are slightly soft-rotted, but with no trace of yellow bundles, and two have entirely 
decayed. 

Notes on plant No. 85. — One plant of Gigantea. four leaves plunged 8 to 7 cm.; 
six healthy plants in same pot are held for comparison. 

March 80. No symptoms. 

July 1. The bulb ha.s rotted, and it is too late to determine the cause. The bulbs 
of all the check plants have also rotted. 

Notea on plant No, ,W.— One plant of Gigantea. five leaves plunged 2 to 7 cm.; 
three healthy plants in the same pot were held for comparison. 

March 30. No symptoms. 

July 1. Leaves dead. Heart of bulb rotted out. No symptoms of the yellow dis- 
ease in the scales which remain. The checks are also free from this aisease. One of 
them has soft-rotted. The centers of the other two are also soft from the presence 
of the white rot. 

INOCULATIONS OF 1899. 

SERIES 19 (HYACINTHS), 

This experiment, begun February 22, was another attempt to infect 
through the blossoms. From 4 to 10 flowers were inoculated by put- 
ting several small drops of the Infectious fluid into the heart of the 
blossoms by means of a sterile hypodermic syringe. For infection, I 
made use of slime from an activelj^ motile young bright-yellow cul- 
ture on coconut. This slime was dissolved by shaking in a small 
quantity of distilled water. 

The varieties tested were Regulus,,blue Bar&n von Tuyll, w^hite 
Baron von Tuyll, Gertrude, and Gigantea. 

The experiment was unfortunately interrupted on June 7, at whicli 
time the bulbs of 8 of the inoculated plants were visibly affected by 
the j^ellow disease, i. e., about one-third of the wiiole number. About 
40 ijlants were held as checks, none of which showed any external or 
internal symptoms of the disease. Regulus was affected to a gi-eater 
extent than the others, but in all cases the symptoms were slight, and 
some months more would have been necessai-y for the bulbs to become 
seriously diseased. 

REMARKS ON PATHOGENESIS. 

Th(^ Inoculation experiments were all made with pure cultures, on 
sound i)laut.s, in a liothouse where hyacinths had never before been 
grown, and in a country where tlie disease is not known to occui*. 
Moreover, none of the several luindred check plants contracted the 
di.scasc. It is therefore reasonal)ly certain that all of tlie infectious 
matei-ial was derived fi-om my cultures. The i)athogenic natui-e of 
these cultures is rendered certain (1) because tlie symptoms always 
began in that part of the plant wliich was iiuK'ulated and i)rocee(k'd 
downwai-d, the bulb l)eiug the last part, to show the di.sease; (2) l)ecause 
the organism occurring so abundantly in the yellow bundles of the 
bulbs was demonstrated by cultures therefrom and by microscopic 
examinations to be tlie same as tliat Inserted into tlie leaves and 
scapes months earlier; {:)) because, after cultivation on artificial 
8970— No. 20—00 8 



84 

media for a year, this organism again produced the disease when 
inserted into the leaves and floral organs of health}' plants, and, after 
a lapse of some months, was again demonstrated to be present in 
enormous numbers in yellow broken-down bundles in the interior of 

the bulbs. 

The time of first appearance of sj'mptoms in the inoculated leaves 
varied within wide limits, according to the variety tested and the 
amount of material used, but nearly all the specimens of Hijacintlius 
orientaJis which were inoculated showed the disease in three to thirty 
days in the parts above ground, and 40 of these plants also showed 
characteristic symptoms in the bulbs at the end of two to five months. 
In 1898 the conditions toward the end of the experiments were very 
unfavorable to the progress of the disease, owing to the extreme heat 
of the summer. In 1899 the experiments were disturbed and broken 
off too soon. 

The results I have obtained indisputably confirm Dr. Wakker's 
statements respecting the aetiology of this disease. My studies lead 
me to accept substantially all of his statements regarding the char- 
acter and succession of symptoms in this disease and the lesions in 
the liost plant due to its progress. They seem to show that some 
varieties are more susceptible than others, e. g.. Czar Peter than 
white Baron von Tuyll, and Gertrude than Gigantea. They show, 
as Wakker stated, that daughter bulbs contract the disease from 
mother Imlbs. They do not clearly establish that the germ has any 
other host plant or that the parasite can enter through the stomata. 
They show that it is easy to induce the disease by wounds. Tliey 
also indicate that bulbs may sometimes become diseased as the result 
of germs lodged in the flowers, and that bees sometimes visit such 
flowers. The last two facts point to leaf-eating and nectar-sipping 
insects as probable carriers of this disease. A priori, there is noth- 
ing improbable in this view, since two bacterial diseases common in 
the United States, the cucurbit wilt and the pear blight, are dissemi- 
nated in this way, the former from germs lodged in the leaf, princi- 
pally by the bites of leaf -eating beetles, the latter from germs lodged 
in the nectaries by bees and other insects which visit the flowers for 
nectar and pollen. It remains, however, for some one in the Nether- 
lands, where the bulbs are grown in quantity, and where the disease 
is prevalent, to remove this statement from the domain of likelihood 
to that of actual fact or to show that it has no real foundation. 

Wakker believed the disease to be often transmitted by the knife, 
and there is every reason to think his views well founded. In this 
case the practical deductions are easily made. Knives used on dis- 
eased plants should not be used on healthy plants until they have 
been thoroughly disinfected. For this purpose it is only necessary 
to dip them into boiling water for a few minutes. 

Possibly healthy fields may become infected from the slime of the 
canals, into which, I am told, diseased bulbs are commonly thrown 



35 

and from which tlie fertile mud is raked out at stated intervals to 
spread over the land. From the close resemblance of this germ to 
Ps. camjjesfris, the cause of brown rot in the cabbage, it is probable 
that, like the latter, the hyacinth germ is able to live for a long time 
in the soil of infected fields. 

Diseased bulbs should be burned or put into a jar pf dilute crude 
sulphuric acid, to which more acid is added from time to time. They 
should never be thrown into the canals or on waste land, nor should 
they be allowed to rot in place, for in this way all the soil would 
finally become infected. Land on which the disease is present should 
be used for other plants. 

As suggested by Wakker, new varieties should be originated only by 
hand pollination, both parents being selected from such varieties as are 
naturally free from this disease, or which are at least little subject to it. 

In concluding these remarks on pathogenesis it may be well to call 
special attention to certain features of this disease which seem espe- 
cially instructive. The peculiarities which have impressed me most 
are: (1) The extremely slow progress of the symptoms — a slowness 
which is very remarkable if we compare it with the rapid action of 
such bacterial diseases as pear blight {Bacillus anujlovorus) or the 
wet white rot of hyacinths which attacked some of my plants in 1898. 
(2) The extent to which the disease is restricted to the particular 
vascular bundles which are first invaded, i. e., the very slow invasion 
of the parenchyma and of remoter vascular bundles protected hy this 
parenchyma. 

This disease is not only peculiarly a vascular trouble, as Wakker 
pointed out, but is so restricted to the bundles first invaded that it 
seems to me impossible that there should ever be anj^ general infec- 
tion of the bulb scales until after the vessels which form a network 
in the plateau have become diseased. The disease was not observed 
in the roots. 

The conditions under which this organism can grow parasitically 
appear to be narrowly restricted. It is not known to occur on any 
other host plant. It is a feeble, slow acting parasite and probablj' it 
would be confined to the domain of pure saprophj^tism were it not 
for the aeration and other peculiarly favorable conditions occurring in 
the vascular bundles of the hyacinth. The parenchyma of the bulb 
scales is distinctly acid and plainly unfavorable to its growth, most 
likel.v on account of this acidity, since studies of the organism in a 
variety of culture media have shown it to be peculiarly sensitive to 
the presence of acids, even those of tlie hyacinth (see Bulletin 28). 

If the parench^'matic tissues of the hyacinth were less acid, if the 
germ were a more c()i)ious alkali produciM-, if it were less strictly 
aerobic, if it destroyed cell walls more readily, or finally, if it exerted 
a more powerful diastatic action on starch, it would, in my opinion, be 
a much more active parasite. 



36 

It is probable that a slight difference in the acidit}' of the paren- 
chyma in different varieties of hyacinths is what renders some varieties 
more vsusceptible than others, but this can not be settled without fur- 
ther experinients which were best undertaken in the Netherlands, 
where according to Wakker the growers have long recognized that 
there are susceptible and nonsusceptible varieties. 

The reader will be better able to judge of the correctness of these 
conclusions after reading Bulletin No. 2<S in which the cultural pecu- 
liarities of this organism are discussed and compared with those of 
Ps. campestris, Ps.pliaseoli, and Ps. stewarti, three other 1-flagellate, 
j^ellow bacteria common in the United States. 

MORPHOLOGY OF THE PARASITE. 
SIZE AND SHAPE. 

This organism is a medium-sized slender rod, multiplying b}' fission. 
The ends are rounded. It is slightly variable in breadth and, under 
certain circumstances, greatly variable in length. Indeed, according 
to varying external conditions the length may be said to fluctuate 
enormoush'. Many examinations and measurements have been made. 
In the plant and in exhausted culture media it is generally only a 
single rod 1^ to 2 times as long as broad ; rarely more than twice as long 
as broad. The appearance of some of the rods, which were taken 
from the daughter bulb examined in February, 1808, is shown in Plate 
I, fig. 8«. On slides stained 5 minutes in a saturated watery solution 
of basic fuchsin the}^ were 0.4 to 0.5 by 0.5 to 1.0 //. From the interior 
of a bulb of the first series (the slide stained June 23, 1807, in Avaterj^ 
solution of basic fuchsin and mounted in Canada balsam and measure- 
ments made August 8, 1808), they were O.o by 0.0 to 1.5 //, most of the 
rods on this slide being 0.5 by 1.0 to 1.2 /.i. Taken from fresh cultures 
in beef broth they are a little longer. Plate I, fig. Sh shows tj^pical 
forms from an alkaline beef-broth culture days old. The thickest 
rods observed on slides made from this culture and stained in a 
saturated water}^ solution of basic fuchsin were 0.(] //. Most of them 
measured 0.4 by 1.0 to 2.0/^. On slides made the third day from a 
well clouded 1,000-cc. flask of distilled water containing 20 cc, of beef 
broth, and stained with Dr. V. A. Moore's modification of Loeffler's 
flagella stain, they were 0.5 to 0.7 by 1.0 to 2.0 /<. On slides made 
from slant agar cultures 5 days old (stock 207, acidity -|- 22 of Fuller's 
scale), and stained with Alfred Fischer's flagella stain, the largest 
rods were 0.8 to 1.0 by 2.0 to 8.0 //. Some of these flagella-bearing 
rods are shown in Plate I, figs. Oa and !»6. Flagella stains seemed to 
slightly increase the thickness of the rods or to render visible an 
outer part not stained by ordinary methods. In general the elements 
of this species appeared to me slenderer than those of Ps. campestris. 
Under the same conditions Ps. phaseoli is also a little plumper and 



37 

shorter. Flagella-beariiig rods of the former are shown in Plate I, fig. 
10, and of the latter in Plate I, fig. 11. 

Rods were frequently seen in process of division, and occasionally 
two pairs were found joined end to end. Chains were never seen in 
the host plant or in young cultures. Even in old cultures in beef 
broth (rim excluded) and on potato and standard nutrient agar free 
from sugar, they were very rare. Prolonged search would, however, 
sometimes be rewarded by the discovery of a chain of 6 to 12 seg- 
ments. As in case of Ps. campestris the tendency to form chains in 
the ordinar}' culture media is very slight. In sugar agar, on the con- 
trary, and also on banaiia, sweet potato, etc., chains and long rods 
are ver}'^ common. These are usuallj^ mixed in with zoogloete and 
the short elements. In such media the short elements often grow 
out into undivided filaments 50 to 150 a< iu length. In many of these 
1 was unable to discover even a trace of septa. In others the seg- 
ments were distinct. Transferred to alkaline beef broth or common 
agar the long rods and chains disappear and the ordinary form 
abounds. This growth in the form of chains and filaments was 
observed repeatedly in cultures abounding in sugar; in fact, it may 
be produced at will by inoculating this organism into agar rich in 
grape or cane sugar. Two of these long rods taken from a 30 per 
cent cane sugar agar are shown in Plate I, fig. 8c. Ps. campestris and 
Ps. phaseoU behave in the same way ;n the presence of an excess of 
sugar. 

No branched forms have ever been seen. Like Ps. campestris some 
of the rods appear to be slightly curved, but the chains are not 
crooked or twisted, as in case of vibrios. 

MOTILITY. 

The organism is motile, at least in early stages of its growth, in a 
variety of media. These movements, which are tumbling and dart- 
ing, are accomplished by means of one long polar flagellum. This 
flagellum was stained only after repeated trials. It must be very 
effectually mordanted. I finally succeeded with Van Ermengem's 
nitrate of silver method, with Fischer's stain, and with Dr. V. A. 
Mooi-e's modification of Loeflfiei-'s stain. As a rule tlie flagella were 
only feebly stained. The ai)pearance of this organ is shown in Plate I, 
fig. l». Figures of the flagella of Ps. campestris and Ps. pliaseoli are 
introduced for comparison. In some cases it seems as if the flagellum 
were given off slightly below the end of the rod, both in this species 
and in Ps. campestris, but of this I could not be entirely certain. 
Motility was observed in potato cultures -2 to 4 weeks old, but I was 
never able to see any in rods taken dii-ectly from the closely packed 
yellow masses inside the bundles of diseased bulbs. This material 
was examined very carefully in distilled water. 



38 



^K 



m 



ZOOGLCEJE. 

Zoogloese are usually" developed in solid and fluid cultures after a 
few days, the time of appearance varying greatly with the nature of 
the medium. In general they appeared much sooner in acid fluids 

than in alkaline ones. In beef broth made very 
^1 stronglj' alkaline to litmus (neutral to phenolphta- 
lein) by means of caustic soda, they did not appear 
until the close of the second week. In acid beef 
broth (unneutralized) they were commonly visible 
to the naked eye a daj' or two after clouding. In 
one instance, however, they appeared in an alkaline 
gelatin culture the second day after inoculation and 
were very numerous the third dsLj. This gelatin 
was strongly alkaline with caustic soda (neutral to 
phenolphtalein) and was in a fluid state (28° to 29° 
C), i. e., in a condition where any substance unfa- 
vorable to growth could act on the organism most 
effectively. May it not be that the zoogloea stage is 
a f>rotective state entered into by bacteria whenever 
the physical or chemical conditions of the substra- 
tum are unfavorable to growth, these conditions 
being either independent of the organism, as in this 
case, or brought about by its own metabolism? 

In beef In-oth and other fluid cultures the tiny 
aggregations of this organism showed a marked 
tendencj^ to gather into a ring or rim on the wall of 
the tube at the level of the liquid, and sometimes 
floating islands appeared, but the flocculent matter 
seldom united into any tough pellicle, being easily 
jarred apart and into the depths of the fluid. These zooglo^fe appear 
to the naked eye either as small whitish flecks or, Avhen on the rim at 
the surface of the liquid, as round, yellow, colony-like bodies, espe- 
cially when they have reached some age and 
density. These bodies also formed on substrata 
rich in assimilable sugars; here, perhaps, owing 
to the development of acids. On the solid, sugar- 
rich substrata, e. g., sugar-agar, potato with 
sugar, sugar beet, sweet potato, etc., they pro- 
duced a papillose, verrucose, or shagreen-like 
surface, the tiny rounded elements forming this 
surface being very smooth and distinct in their 
upper part, but fused below next to the substratum. This shagreen 
also appeared, on old cultures, on nutrient starch jelly containing 5 per 
cent glycerol. This appearance is shown in figs. 3 and 4. 



Flu. o.— Culture of 
Pseudomonas hya- 
cinthi on slant 30 per 
cent cane-sugar agar, 
showing "shagreen" 
surface. 




Fig. 4.— Slightly magnified 
diagrammatic views of 
slime of Ps. hyacinthi on 
sweet potato, showing 
"shagreen ■■ surfaoe. 



39 

SPORE FORMATION. 

No spores have been seen, and I am in considerable doubt as to 
whetlier the spores observed in some of his cultures and studied so 
carefidly by Dr. Wakker belonged to this species. He was never 
able to find any in the host plant, and those which appeared in his 
tubes may have been due to the fact that he was working at times 
with contaminated cultures. None of his successful infections with 
sporiferous material were made with spore masses entirel}^ free from 
vegetative rods, and the latter are long-lived. This supposition of 
mixed cultures is the more likely because his work was done at a 
time when it was impossible to decide with ease and certainty on the 
purity of any given culture — i. e., before the era of poured plates — 
and especially because some of his gelatin cultures were certainly 
contaminated, i. e., yielded gas bubbles. (See Fermentation tube 
experiments described in Bulletin No. 28 dealing with the cultural 
characters of this organism.) While, therefore, not wishing to deny 
absolutely the existence of spores in this species, it seems to me that 
further and more exact proof is necessary to demonstrate their occur- 
rence. A great many old cxdtures, grown on a variety of media at 
18° to 26° C, have been examined without finding any spores. None 
were observed in the diseased bulbs, many of which were examined 
with care. Neither did any spores form in cultures exposed for fif- 
teen da3"s to air deprived of its oxygen by the potash-pyrogallic-acid 
method (test by microscopic examination and by exposure for ten 
minutes to 60° to 70° C. in alkaline beef broth). None developed in 
solid or fluid cultures exposed six weeks in the thermostat at 34° to 
35° C. These cultures included alkaline and acid beef broth and 
cylinders of turnip and sugar beet standing in distilled water. Fur- 
thermore, this germ will not grow at all or grows onlj' very feebly at 
the temperature Avliich Dr. Wakker states to be most suitable for the 
formation of the spores viz. 35° C. (See Maximum temperature for 
growth, in Bulletin No. 2S.) Finally, no spores developed in cultures 
which were first grown foi' a week or two at room temperatures and 
then put into the thermostat at 34° to 35° C. Several different media 
were tried, but vigorous growth stopped immediately, and after two 
weeks all such cultures were dead. 

INVOLUTION FORMS. 

Some astonishing involution forms have been observed. They 
formed a whitish i-inx at the surface of the fluid in strongly (soda) 
alkaline beef-broth cultures to which 10 per cent cane sugar had been 
added. The color was so pale that at fii-st the tubes wei-e su])posed to 
be contaminated. Wheu examined mici-oscopically the cultures were 
five weeks old. These bodies wei-e so immensi-ly swollen, fused, 
twisted, and irregular in outline that seen on the slide no one to wliom 
1 showed them liad any suspicion tliat they were bacteria. Involution 
forms were also seen on old tui-nip and banana cultures. 



40 

BEHAVIOR TOWARD STAINS. 

Beyond the fact that the flagelhini was stained with difficulty and 
that old growths, whether in the plant or out of it, took stains feebl}^ 
nothing- peculiar was observed, unless it be that the bacterial j^recipi- 
tate resulting from growth was not stained in Dunliam's solution con- 
taining methylene blue, and was stained in the same medium with 
rosolic acid. The following are transcripts from records scattered 
through my notes: 

Germs from an old culture in strongly alkaline (soda) beef broth 
stained slowly and rather feebly in a saturated alcoholic solution of 
gentian violet diluted with an equal bulk of distilled water and allowed 
to act for half an hour. This culture had lieen killed by heat in the 
thermostat. Germs from an old culture in acid beef broth which had 
become alkaline, stained feebly in Ziehl's carbol fuchsin with ten 
minutes' exposure. This, also, was undoubtedlj- a dead culture. 
Germs from a month-old culture on sugar beet were exposed for some 
time to a dilute watery solution of gentian violet, whereupon all the 
zoogkea^ stained deeply, but tlie loose rods rather feebly. On long 
exposure (over an hour) everything stained deeply. Germs from 
sweet potato cultures a month old (zoogloese, rods, doublets, and 
chains) stained feebly in a deep-colored Avatery solution of gentian 
violet, although exposed for one-half hour. Germs taken from one of 
the bright-yellow bundles of a diseased bulb (June 23, 1897) stained 
feebly in water made deep red with Griibler's basic fuchsin. Germs 
from the yellow bundles of another bulb (Feb. 3, 1808) showed a verj^ 
weak stain after five minutes' exj)osure to water saturated with Grii- 
bler's basic fuchsin. Exposed two minutes to water saturated with 
gentian violet, the stain was much better, but not deep enough. The 
rods from j'oung cultures stain readily. 

SYNOPSIS OF CHARACTERS. 

For convenient reference I have drawn up the following brief 
account of this organism : 

Pseudomonas hyacinth i ( Wakker) . A yellow, rod-shaped organism, 
multiplying by fission; ends rounded; single, in pairs, or 4's, more 
rarelj" in the form of chains or filaments; motile b}^ means of one polar 
flagellum. In the host plant, when the bundles are crowded full of 
the 3'ellow slime and broken down, it is, generally, 0.8 to 1.2 hj 0.4 
to 0.6 /<. In alkaline beef broth or on agar it usually measures 1.0 to 
2.0 b3^0.4 to 0,6 //. In old cultures rich in sugar it often grows out 
into long, slender chains, or into filaments (50 to 100 a^ long) in which 
there are no distinct septa. Nonsporiferous. Color distinctly yellow, 
but somewhat variable. Chrome yellow to pale cadmium in the host 
plant, i, e., bright yellow^ (Ridgway's Nomenclature of Colors). On 



^ Saccardo's Jiavus and citrinus, but brighter (Chromotaxia) . The Standard Dic- 
tionary's i/pjlojc III. lemon . and cauari/. approximately ( under Spectrum ) . Prang's 
yellow. Plate I y. in the Prang Standard of Color. Popular Ed.. No. 1. 



41 



culture media, when not interfered with by the brown pigment, gen- 
erally gamboge, chrome j^ellow, or canary j^ellow, but sometimes paler. 
Old cultures on some media darken from the production of a soluble, 
pale-brown pigment. This feeble brown stain is best developed in 
hyacinth broth, in potato broth with peptone, on turnips, on radishes, 
and on banana rinds. It was not observed in acid or alkaline beef 
broth, on coconut flesh, on sugar beets, in nutrient starch jelly, in agar, 
or in gelatin, with or without sugar. This organism grows readily on 
potato cylinders standing in distilled water, but it never becomes copi- 
ous or fills the water with a solid yellow slime, owing to its feeble dia- 
static action. Potatoes on which it has grown, even for several months, 
always give a strong starch reaction with 
iodine. It behaves the same on nutrient 
starch jelly free from assimilable sugars. It 
liquefies nutrient gelatin and Loetfier's blood 
serum, but does so slowly, and will not liquefy 
gelatin at all if 10 per cent cane sugar is added 
(fig. 6). Growth on nutrient agar or nutrient 
starch jellj^ is inhibited (unless the inocula- 
tion be from a solid culture and very copious) 
by the addition of 10 per cent glycerol, and is 
greatly retarded bj" 5 per cent glj'cerol ; even 



2i 



per cent of glycerol retarded growth. 




Growth in beef broth was much retarded by 
the addition of 1.5 per cent sodium chloride. 
Organism extremely sensitive to plant acids, 
including those of the hyacinth. Aerobic; 
doubtfully, if ever, facultative anaerobic; not 
a gas producer (see fig. 5). Does not redden 
litmus milk, but makes it bluer, and slowly 
separates the casein from the whey b}' means 
of a lab ferment. Produces under some cir- 
cumstances, and slowl}^ a small amount of 
nonvolatile acid (slime acid?) with various 
sugars (grape, cane, etc.), which acid is fre- 
quently obscured by the moderate production 
of alkali. In the presence of air produces an organic acid (probably 
acetic) from ethyl alcohol dissolved in milk or bouillon. Inverts cane 
sugar, but apparently without the intervention of any enzym. Will not 
grow on 30 per cent grape-sugar agar. Resists dry air very well, i. e., 
more than forty-eight days when spread on cover glasses in thin layers. 
In Dunham's solution with methylene blue the color is reduced in 
a few days, but reoxidizes quickly on shaking; final color (56 days) 
bright blue. In Dunham's solution with indigo carmine the color 
changes to a briglit blue, which persists for a long time; final color 
yellowish. In Dunham's solution with rosolic acid and enough IICI 



Fig. 5.— Typical behavior of Ps. 
hyacinthi in fermentation 
tubes containing peptone 
water, or peptonized beef 
bouillon, with addition of vari- 
ous sugars and other carbohy- 
drates. Fluid clear in closed 
end, clouded in U and open 
end. 



42 



to render the fluid yellowish, Ps. hyacinth i did not redden the fluid, but 
made it colorless, the bacterial precipitate becoming rosy or salmon- 
colored. Produces indol slowly in peptonized beef broth and in pep- 
tonized Uschinsky's solution; does not produce nitrites in these 
solutions. Does not reduce potassium nitrate to nitrite in peptonized 
beef bouillon. Not a strong-smelling germ. Not readily destroyed 
bj^ its own decomposition products except in media containing alcohol. 
Will not grow in the thermostat at 37° C, and grows verj- feebly on 
some media and not at all on others at 34° to 35° C. Optimum tem- 
perature 28° to 30° C. , or thereabouts. Minimum temperature approx- 
imately 4° C. Thermal death point (10 minutes' exposure) 47.50° 
C. ; nearly all the rods are killed at 47° and a great many at 46.50° C. 

Did not grow at room temperatures after 6 days 
exjDOSure in alkaline beef broth in the thermo- 
stat at 35° to 36.35°. Does not grow well in 
Uschinsky's solution. Grows much better in 
Uschinsky's solution when j)eptone is added to 
it. Grows well with a bright yellow color on 
cylinders of steamed coconut flesh, standing 
with one end in distilled water. 

Pathogenic to hyacinths. Enters the plant 
through wounds, through the blossoms, etc., and 
multiplies in the vascular system, filling the ves- 
sels, especially those of the bulb, with a bright 
yellow slime consisting of bacteria. The walls 
of the vessels are destroyed and extensive cavi- 
ties are formed in the bundles. The parenchyma 
around the bundles is also involved, but only 
very slowlj-, the organism being a feeble de- 
stroyer of cell walls. The host plant is not 
rapidly destroyed, a year or more being neces- 
sary. The cells are first separated by solution 
of the middle lamella, but the wall itself seems 
to finally disappear. The cavities contain innu- 
merable bacteria mingled with fragments of the dissolved bundles and 
of the surrounding parenchyma. 

First described by Dr. J. H. Wakker from the Netherlands, where 
it often causes serious losses in the hyacinth gardens. Not known to 
occur in any other part of the world. 




Feb. 10 



JMar.l4 



.Apr. 12 



Fig. 6.— Ps. hi/acinthi grow- 
ing in strongly alkaline 
(0) gelatin with 10 per 
cent cane sugar. No lique- 
faction. The surface 
curves are due to the very- 
gradual drying out of the 
gelatin. 



REMARKS ON RELATIONSHIP. 



CloseU" related to Ps. campestris (parasitic on Cruciferous plants), 
Ps. phaseoU (parasitic on beans), and less so to Ps. stewarti (parasitic 
(?) on corn, especially sweet corn). Readily distinguished from the 
two organisms first named by (1) its brighter color; (2) its lower 
thermal death point; (3) its manner of growth on potato cylinders 



43 

standing in distilled water, i. e., by its feeble action on starch; and 
(4) its pathogenic properties. Other distinctions are given in Bulle- 
tin No. 28. Readily distinguished from Ps. siewarti by (1) its differ- 
ent, brighter color; (2) its feeble growth in Ilschinsky's solution; (3) 
its liquefaction of gelatin and Loeffler's blood serum; (4) its lower 
thermal death point; (5) its lab ferment; (6) its much greater sensi- 
tiveness to acids ; (7) its more luxuriant growth on turnip and rutabaga. 

From facts in possession of the writer it is certain that there are 
many yellow organisms moi-e or less closely related to the four men- 
tioned in this paper, i. e., nonsporiferous, rod-shaj)ed, micro-organ- 
isms, multiplying by fission, possessing one polar flagellura, and 
capable of living parasitically or semiparasitically upon various 
plants. All of these parasitic yellow organisms, at least all I have 
examined, are morphologically quite different from Bacillus coU, 
Bacillus amijlovorus, Bacillus tracheiphilus, or any other micro- 
organism having flagella distributed over its whole surface. They 
also differ in many cultural peculiarities. They are, however, related 
to each other in many ways, and appear to form a natural group. I 
have an idea also that in some species the production of the brown 
pigment, and in others the production of the yellow pigment, has 
been nearly or quite extinguished. The species in which both pig- 
ments come the nearest to being equally well developed is, perhaps, 
Fs. cainpestris. The yellow pigment appears to be a lipochrome. 
(See Bui. 28.) 

There are also, I believe, many morphologically similar yellow 
bacteria which are purely saprophytic. 



44 



EXPLANATION OF ILLUSTRATIONS. 

TEXT FIGURES. 

Fig. 1. Porfion of a bull) scale from plant No. 20. inoculated February 7, drawn 
June 14. showing four health}- and four diseased vascular bundles. The 
parenchyma between two of the latter has largely disappeared, its ■olace 
being occupied by a cavity full of bacteria. Smaller cavities in the paren- 
chyma, close to the vascular tissue, are visible in each one of the diseased 
bundles. The bundle in the middle of the scale also shows the bacterial 
occupation of anastomosing veinlets. The diseased portions w^ere bright 
yellow from the presence of enormous numbers of the parasite, which, how- 
ever, had not reached the surface of the scale. The infection of this scale 
was from below upward. (Page 22.) 

Fig. 2. Leaf of plant No. 25, inoculated February 7, drawn April 80. The figure 
shows shriveled apex and dead central stripe, na-row border of yellow, and 
beyond this to either side healthy green tissue (white in the figure). In the 
yellow border on the right side are some dotted areas intended to represent 
water-soaked tissue: i. e., spots recently invaded apparently by a slow side- 
wise movement of the bacteria from the central stripe. ( Page 23. ) 

Fig. 3. Slant. 30 per cent, cane-sugar agar showing the '• shagreen '" surface. 
Culture No. 9. June 30, 1898. Photographed August 2. (Page 38.) 

Fig. 4. Enlarged diagrammaticverticalandhorizontalviewof a similar shagreen 
surface from a sweet-potato culture twenty days old. (Page 38.) 

Fig. o. Fermentation tube showing behavior of Ps. hyacinthi in peptone water 
or peptonized beef broth with various carbohydrates, e. g., grape sugar, 
fruit sugar, cane sugar, milk sugar, galactose, mannit, glycerin, ethyl alco- 
hol, etc. Maltose is a possible exception, tubes with this sugar having 
finally clouded very feebly in th'^ closed end. None yielded any gas. ( Page 41. ) 

Fig. 6. Stab culture in gelatin + 10 jjer cent cane sugar inoculated Febrnary 
10. On March 14 there was a well-developed stab and a good surface growth, 
but no liquefaction, the curved surface being due to the drj'ing out of 
the gelatin. On April 12 the gelatin had dried out as indicated by the 
dotted line, but there was no liquefaction. (Page 42.) 

PLATE FIGURES. 

Fig. 1. Cross section of the bulb of plant No. 8, inoculated in the upper part of 
the scape February 16. 1897. Photographed June 23, 1897. Six vascular 
bundl( s broken down and filled with the bright yellow bacterial slime. 

Fig. 2. Onion leaf, inoculated January 29. 1898. Painted by F. A. Walpole, 
March 5. The yellow color of the leaf in the vicinity of the inoculations 
was due to the slow and long-continued growth of the organisms: i. e.. it is 
the yellow color of the bacteria showing through. 

Fig. 3. Leaf of plant No. 51 (series 9). inoculated near the apex (at x) on Febru- 
ary 11. Painted by F. A. Walpole, .March 5. The water-soaked lines shown 
in the lower pai't of the stripe were conspicuous. This leaf was injected 
with 0.3 cc. of a cloudy beef-broth culture eight days old, but there were no 
sj'mptoms until after the sixth day. 

Fig. 4. Leaf of plant No. 52, inoculated at the same time, from the same culture, 
in the same manner, and with the same quantity of broth as No. 51 (fig. 3). 
Painted March 5 by F. A. Walpole. Symptoms farther advanced than in 
fig. 3, but none visible the first week. 

Fig. 5. Cross section of the upper part of the bulb of plant No. 63, inoculated 
February 12, 1898. through the flowers. Photographed June 18. Eight 
scales visibly affected (16 vascular bundles). Farther down, near the junc- 



45 

tion of the scape with the plateau, a larger number of bundles and more 
scales were affected. The flattened side of this bulb (upper part of figure) 
is where a daughter bulb pressed against it (see text, page 29). 
Fig. 6. One scale removed from the bulb of plant No. 63 (fig. 5) and photographed 
• by itself, to show the course of the disease in the vascular bundles. The 
parenchymatic tissue between these yellow bundles was sound. 
Fig. 7. Scape of plant No. 79, inoculated February 16 in the blossoms. Painted by 
F. A. Walpole, March 5. The infection proceeded apparently from one 
flower. 
Fig. 8. (a) Ordinary form of bacterial rods found in the diseased bulbs. These 
were taken from the daughter bulb mentioned on page 18, and were stained 
two minutes in a saturated watery solution of gentian violet. X 1,000. (b) 
Ordinary form of rods from an alkaline beef-broth culture nine days old. 
Stained ten minutes in a saturated watery solution of Grubler's basic fuch- 
sin. X 1 ,000. (c) Two long rods from a 30 per cent cane sugar agar thirty- 
eight days old. No segments or septa visible. Van Ermengem"s nitrate of 
silver stain. X 1,000. 
Fig. 9. (a) Flagella stained by Dr. V. A. Moore's modification of Loeffler"s stain. 
Bacteria grown for three days in 1.000 cc. of distilled water with addition 
of 20 cc. of beef broth (see 18th series of inoculations). X 1,000. (b) 
Flagella ^stained by Dr. Alfred Fischer's stain. Bacteria from an agar 
culture five days old. X 1,000. 
Fig. 10. Flagella of Ps.ca»ipe.s-f/-/.s. introduced for comparison. Bacteria from an 

agar culture seven days old. Fischer's flagella stain. X 1.000. 
Fig. 11. Flagella of Ps. pltaseuli, introduced tor comparison. Bacteria from a 
culture twenty days old, on nutrient starch jelly with the addition of lactose. 
Van Ermengem's nitrate of silver stain. Ten minutes in the osmic acid 
mordant at 55 to 60 C. X 1.000. 
Fig. 12. Colonies of Ps. hyacinthi from a poured plate (Petri dish) of + 15.5 agar, 
after sixteen days at 22" to 23 C. The smaller colonies are buried ones. 
This plate was made from the 1.000 cc. flask culture (18th series of 
inoculations). The buried colonies are too deep a yellow in the lithograph. 
Fig. 1 3. A stab culture in 8 per cent nutrient gelatin ( + 48 with malic acid) show- 
ing the very slow liquefaction. Photographed six weeks after inoculation. 
Range of temperature. 17 to 20' C. Upper one-half of the gelatin liquified to 
the walls, bright yellow precipitate and copious yellow rim. Lower one-half 
clear, solid, unstained, and showing in the center the whitish slender thread 
of the bacteria growing, very slowly, along the track of the needle nearly 
to the bottom of the tube. 
Fig. 14. A stab culture in the same gelatin as 13, but with the addition of 5 per 
cent cane sugar. Photographed six weeks after inoculation. Range of 
temperature. 18 to 20 C. Anequally good growth, but liquefaction entirely 
prevented by the addition of the cane sugar. Compare with alkaline sugar 
gelatin (text fig. 6. ) 
Fig. 15. A streak culture on nutrient starch jelly, fourteen days after inoculation. 
No visible growth, owing to absence of readily assimilable carbohydrate 
food. Painted by John L. Ridgway. 
Fig. 16. A streak culture on nutrient starch jelly, fourteen days after inoculation. 
This culture was an exact duplicate of that shown in fig. 15. except that 
before the inoculation 20 milligrams of reprecipitated (sugar free) Taka- 
diastase was allowed to act on the starch one and one-half hours at 34° C, 
so that some of the starch was converted into readily assimilable substances. 
The diastase was then destroj'ed by steaming and the slant surface was 
inociilated in the same way as 15. Painted by John L. Ridgway. 

o 



BUL. 26, DIV. VEG. PHYS. & PATH., U. S. DEPT. AGRICULTURE. 



PLATE L 




ERWIN F. SMITH, F. A. WALPOLE 
AND JOHN L. RIOGWAY. 



A-HOfUl & CO.I-rrHOCAUSTlC.BAi.'nMOKr 



PSEUDOMONAS HYACINTHI (WAKKER) ERW. SMITH. 



Bulletin No. 27. 



V. I'. I'.— 80. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OP VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

^ ALBERT F. WOODS, CHIEF. 



THE WILT DISEASE OF COTTON 
AND ITS CONTROL 



BY 



W. A. ORTON, 

ASSOCIATE PATHOLOOIST. 




WASHINGTON : 

GOVERNMENT PRINTING OFFICE. 
I 900. 



OFFICE OF PLANT INDUSTRY. 

B. T. GrALLOWAY, Director. 

AFFILIATED DIVISIONS. 

Gardens and Grminds, B. T. Galloway, Superintendenf. 
Vegetable Physiology and Pathology, Albert F. Woods, Chief. 
Agrostology, F. Lamson-Scribxer, Chief. 
Pomology, Gr. B. Brackett, Chief. 



DIVISION OF VEGETABLE PHYSIOLOCA AND FATHOLOOY. 



SCIENTIFIC STAFF. 

Albert F. Woods, Chief of Division. 
Merton B. Waite, Assistant Chief. 

associates. 

Erwin F. Smith, Wm. A. Ortox, 

Newton B. Pierce, Ernst A. Bessey. 

Herbert J. Webber, Flora W. Patterson, 

M. A. Carleton, HerMxVnn von Schrenk,' 

P. H. Dorsett. Marcus L. Floyd,- 

Thomas H. Kearney, Jr. 

ix charge of laboratories. 

Albert F. Woods, Plant Physiology. 
Ernvin F. Smith, Plant Pathology. 
Newton B. Pierce, Pacific Coast, 
Herbert J. Webber, Plant Breeding. 

• Special agent in charge of studies of forest-tree diseases, cooperating with the Division of 
Forestry, U. S. Department of Agriculture, and the Henry Shaw School of Botany, St. Louis, Mo. 
- Detailed as tobacco expert, Division of Soils. ) 



Bulletin No. 27. , V. i'. P.-ftO. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

ALBERT F. WOODS, CHIEF. 



THE WILT DISEASE OF COTTON 
AND ITS CONTROL. 



BY 



W. A. ORTON, 

ASSOCIATE PATHOLOaiST. 




WASHINGTON: 

GOVERNMENT PRINTING O F 1' I C E, 
I 900. 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 
Division of Vegetable Physiology and Pathology, 

Washington, D. C'., October 30, 1900. 

Sir: I respectfully transmit herewith a report by Mr. W. A. Orton, of 
this Division, describing brief!}' the progress made in the study of the 
Wilt Disease of Cotton, also known as "Frenching" and "Blight." 
This disease has for several years done serious injury in many parts 
of the cotton belt. The areas affected by it are annually increasing 
in size, and each year brings to the Department repoi'ts of outbreaks 
in localities hitherto supj)osed to be free from the malady. It is at 
present a serious menace to the cotton industry. The parasitic nature 
and life historv of the fungus causing the disease have been thoroughlv 
discussed in a former report by Dr. Erwin F. Smith, of this Division. 
The work of the Department on this disease is still in progress, but it 
is thought best to jDresent a brief outline of the more important results 
obtained up to this time. It has been found that certain races are 
resistant to the malady, and results obtained in the experiments and 
bj' certain growers cooperating Avith the Department indicate that 
resistant strains can be obtained quite readily by selection. All other 
methods of fighting the disease have so far proved ineffective. Every 
effort will therefore be put forth to improve and develop these resistant 
strains. 

I resijectfully recommend that this report be published as Bulletin 
No. 27 of this Division. 

Respectfully, Albert F. Woods, 

Clt ief of Division . 

lion. James Wilson, 

Secretary of Agriculture. 
2 



CONTENTS. 



Page. 

Distribution - - - ^ 

Extent of loss - ---- -- - '^ 

Description of the disease - ^ 

Cause of the disease " 

Natural infections — - - ° 

Artificial infectious ... - ■ - - ° 

The failure of soil fungicides - ■ ^ 

Preventive measures 1^ 

Hygienic treatment ... 1^ 

Selection of resistant races - H 

Control of other wilt diseases by selection -- 14 

Conclusions ...... --- l'^ 

Explanation of plates -. ■ I*' 

3 



ILLUSTRATIONS. 



Page. 

Plate I. Fig. l.—Wiltdiseasein upland cotton, Dillon, S.C. Fig. 2.— Healthy 

field of upland cotton, Dillon, S. C. _. 16 

II. Fig. 1.— .Tannovitch, an Egj-ptian cotton, on the left; King, an 
upland cotton, on the right, showing comparative resistance to 
the wilt disease. Fig. 2. —Jackson on the left, Drake on the right, 
showing comparative resistance to the wilt disease ... 16 

III. Fig. 1. — Root tufts produced on Jannovitch cotton l^y repeated par- . 

tial infections by the wilt fungus. Fig. 2. — Egyptian cotton 
plants fi'om infected and noninfected soil, showing dwarfing 
effect of the wilt fungus. -_ _, .. .__ 16 

IV. Sea island cotton resistant to the wilt disease. The result of selec- 

tion from resistant plants _ _ . . 16 



WILT DISEASE OF COTTON AND ITS CONTROL. 



DISTRIBUTION. 



The wilt disease is now known to occur on the coast of South Caro- 
lina, where it attacks the fine sea island cotton, and at Dillon, 
Salters, and other places in the same State, where it attacks upland 
cotton. 

Prof. F. S. Earle, of the State experiment station, reports it to be 
widely distributed in Alabama, particularly in the southern part, 
and states that it is undoubtedly growing worse from year to year. 
It has been reported from many localities in Georgia, and is known to 
occur in Florida and Arkansas. 

It is certain that this disease is widely distributed through the 
Southern States, and it is probable that it occurs in many places 
where it has not yet been distinguished from other troubles, such as 
"rust" and the effects of lightning. 

EXTENT OF LOSS. 

The annual loss from the wilt disease is very considerable. It is 
more keenly felt by the individual planters than most cotton troubles, 
because the disease remains in the soil and grows worse with each 
succeeding crop. On the sea islands of South Carolina alone a careful 
estimate indicates that nearly, if not quite, one-third of the land 
planted to high-grade cotton is affected by this disease, the large)- 
portion of it so l^adly that it is no longer profitable to plant it in cot- 
ton. In many instances it has been necessary to abandon from 20 to 
50 acres on a single plantation. Much of this land is tile-drained and 
in a high state of cultivation. No other crop has been so profitable as 
the sea island cotton, and the iiroblem l)efore these planters is a very 
serious one. The loss to the planters of upland cotton in areas 
affected by the disease has been proportionally great. On one farm 
in Dillon, S. C., where the Department has been conducting some 
experiments, 15 acres of fine land are already affected and the disease 
is spreading rapidly on this and adjoining plantations. The result of 
planting these infected soils with the ordinary varieties of cotton is 
shown in Plate I, in which fig. 1 shows a field of diseased cotton and 
fig. 2 a field of healthy cotton. The loss to this community from the 
wilt disease the past season is estimated at several thousand dollars. 
In Alabama the loss from this disease is reported from many sources to 
be very large. 



6 

The importance of the disease, however, does not lie so much in the 
amount of the present loss as in the danger of its future increase, for 
it must ultimately spread so much as to entail far greater losses and 
possibly threaten the life of the industry unless the methods for its 
control are perfected. 

DESCRIPTION OF THE DISEASE. 

The wilt is very distinct from any other disease of cotton, so that 
there need be no difficulty in its identification. It usually makes its 
first appearance in the spring about the last of May, when the iDlants 
are 6 to 8 inches high. It appears in well-defined areas, which enlarge 
if cotton is planted on the same land again. The first outward indi- 
cation of its presence is a dwarfed growth and unhealthj^ appearance 
of the plants. The leaves turn yellow between the veins, their mar- 
gins shrivel up, and some plants wilt and die at once. In other plants 
the progress of the disease is often slow, and many of them live the 
entire summer and die late in the season. On cutting across the stem 
of a diseased plant, the woody part will be found to be stained brown 
Avherever the disease is present. In the absence of microscoi^ic 
examinations, this brown discoloration of the internal tissue is the best 
ocular evidence of the presence of the wilt disease. 

Plants may partiall}^ recover from a severe attack of the wilt disease 
b}' the development of strong lateral branches near tlie ground. Such 
l^lants may be distinguished by their dwarfed and bushy aiJijearance 
and by the tendency of their branches to lie prostrate on the ground. 

CAUSE OF THE DISEASE. 

The cause of the wilt disease of cotton is a fungus, Neocosmospora 
vasinfecfa (Atk.) Erw. Sm., which attacks the plant from the soil. 
It first enters the smaller roots and subsequently grows from these 
into the taproot and stem, filling the water ducts with its mycelium. 
The result is that the supply of food and moisture carried up from 
the roots is greatlj^ decreased and the symptoms described above are 
produced. The nature of the fungus has been full)' discussed in 
Bulletin No. 17 of this Division,^ and it will not be necessary to enter 
into details here, but only to outline the subject and to record some 
additions to our knowledge. 

The wilt disease of okra is believed to be caused by the. same fungus 
which produces the cotton wilt. No inoculation experiments have 
been tried, but in the experience of the writer okra has never failed 
to contract the disease when planted in fields infected with the cotton- 
wilt disease. 

1 Smith, Erwiu F. Wilt Disease of Cotton, Watermelon, and Cowp6a. 1899. 



7 



Both the wilt disease of okra and that of cotton are sometimes com- 
plicated by the presence in the field of the root nematode, Heterodera 
radicicola. The combined attack of these two parasites results in some- 
what greater injury to the plants than would be caused by either one 
alone. This is particularly true of okra, which suffers considerably 
more from the attacks of the nematodes than cotton growing- beside 
it. It is not believed by the writer, however, that the assistance 
of the root nematodes or of any fungus is necessary to allow the 
wilt fungus to gain entrance to the roots of cotton. Some of the 
worst cases of wilt disease that have been observed were on land 
where no root nematodes could be found. Nor is it believed that 
mechanical injury to the roots from cultivation or other causes is 
necessary to produce infection. Cotton planted on infected fields 
late in the season, after cultivation had ceased, and when conditions 
were not favorable to the growth of damping-off fungi in the soil, 
contracted the disease at the usual time. The indications are that 
the fungus is a sufficiently aggressive parasite to make its way unaided 
into the vascular system of the plant whenever the plant is liable to 
infection. 

The progress of the disease is always slow as compared with that of 
other plant diseases. The period of incubation, or the time elapsing 
after the young seedling is exposed to the attacks of the fungus and 
before the disease becomes manifest, is usually at least forty days and 
often much longer. Much depends onthe individual plant itself. The 
conditions which favor the progress of the fungus through the plant 
are not fully understood, but from some observations that have been 
made it is l:>elieved that highly fertilized plants, growing vigorously, 
succumb more readily than those which have grown on poorer soil. 

In the early history of the wilt disease the cause was supposed by 
the planters to be the excessive applications or injudicious use of 
conunercial fertilizers, and many of tlie leading planters in the Sea 
Islands made careful experiments with various modifications of their 
fertilizers, such as the use of marl, salt mud, kainit, and lime, and 
the increase oi- decrease of the proportions of phosphoric acid and 
potash. Mr. W. G. llinson, of James Island, South Carolina, a very 
successful planter, has informed the writer that the result of all these 
trials has been to convince those who made them that the disease 
can not be controlled by any changes in their system of fertilizing. 

The wilt disease occurs in so many widely separated localities and 
under such varied cultural conditions that it is not probable that any 
errors in tlie agricultural practice are the primary cause of tlie trou- 
ble, although the planting of cotton year after year on the same land 
and tlie common practice of plowing under the last year's stems in 
preparing the ground in the spring ])()th t(!nd to hasten the spread of 
the wilt fungus after it has once been introduced. 



8 

NATURAL INFECTIONS. 

The effect of repeated infections of the small roots of the cotton is 
very noticeable, especially when the plants are somewhat resistant to 
the disease. Small tufts of roots ^row from each i^oint of infection, 
doubtless on account of some stimulus exerted by the fungus. Sev- 
eral short roots will thus start from a place which would normally 
have produced one longer branch. (PI. Ill, fig. 1.) 

Many of these little roots are killed by the fungus and others grow 
in their places, so that the tufted appearance of the rootlets is more 
pronounced late in the season. The same result has been produced 
in the laboratorj^ by inoculating seedling cotton plants with x^ure cul- 
tures of the cotton-wilt fungus. Similar root tufts are found associ- 
ated with the wilt diseases of okra, cowpea, watermelon, and cabbage, 
and they are believed to be characteristic of this class of root diseases. 

In the case of cotton their presence on the roots demonstrates the 
presence of the wilt fungus in the soil, even Avhen the amount is so 
small that no harm is visible aside from the reduced growth of the 
plants. (PI. Ill, fig. 2.) This dwarfing of the plants is due to the 
killing of the small roots and is often visible over a considerable area 
surrounding a badly infected spot. For this reason the loss in yield 
on such a field is much greater than would appear simply from a 
consideration of the badly diseased areas, as the dwarfing due to the 
injuring of the small roots considerably curtails the yield. 

ARTIFICIAL INFECTIONS. 

Since the publication of Bulletin No. 17, the wilt disease has been 
I)roduced in healthy cotton plants by inoculating the soil in which 
the}' grew with pure cultures of conidial stages of Neocosmospora 
rasinfecta. This removes any doubt as to the causal relation of the 
fungus to the disease which might arise from the failure of the pre- 
vious inoculation experiments. The plants were grown for a few 
weeks in pots, and then a small quantity' of fungus from a pure cul- 
ture was placed in the bottom of each one. Eight days later thej'^ 
were transplanted to the open ground. The first case appeared after 
about 35 days. Fourteen out of 24 plants contracted the disease. 
The fungus was abundant in the vascular bundles of 7 i^lants and 
tliej^ showed all the other symptoms of the disease. The other 7 
infected plants were onl}^ slightly diseased, although the fungus was 
found in the vessels of the stem. The check plants, 25 in number, 
all remained healthy. It will be noted that the length of time 
between the inoculation of the soil and the appearance of the dis- 
ease in this experiment (35 to 50 daj's) was practically^ the same as 
elapses in the field between the germination of the seed and the first 
appearance of the disease. That a larger proj)ortion of the inocula- 
tions did not succeed is believed to be due to the small amount of 



9 

fnngiis used and to the natural resistance of the plants. The cotton 
plant inoculations described in Bulletin 17 were all made in the green- 
house and it is now believed that the negative results were due either 
to the slow growth of the plants or to the fact that they were natu- 
rally resistant. 

THE FAILURE OF SOIL FUNGICIDES. 

Careful experiments have been made with a large number of sub- 
stances applied to the soil in the hope of killing the fungus, but all 
the results obtained up to the present time indicate that there is no 
hope of success from the use of any fungicides sprayed on the plants 
or applied to the soil. 

Fields uniformly infected with the wilt disease were selected, and 
over twenty different substances were applied in amounts as large as 
it was thought safe to use. In many cases the expense of their appli- 
cation in such quantities was so great as to make their use impracti- 
cable had they proved efficacious. In other cases, as in the use of 
materials containing copper, continued applications in such large 
quantities would be likely to injure the soil. 

The following were among the fungicides tried, nearly all of which 
were tested in duplicate or triplicate (in different localities): 

1. Bordeaux viixture, 1,200 gallons per acre, applied to the soil ten days before 
planting. 

3. Bordeaux mixture, 1,300 gallons per acrje, applied to the soil before planting 
as above, and also sprayed on the plants and soil at intervals during the summer. 

3. Bordeaux mixture, 1,300 gallons per acre, with the addition of a small quan- 
tity of molasses to increase the solubility of the copper. 

4. Bordeax mixture and.sulpliiir, i>reY)ared by adding to each barrel of a mix- 
ture containing the ordinary amounts of copper sulphate and lime 6 pounds of 
sulphur and (i pounds of lime that had been boiled together one hour. This was 
mixed with the soil in the row ten days before planting. 

5. Bordeaux mixture, 3,600 gallons per acre. This is equivalent to 546 pounds 
of copper sulphate per acre, but the cotton grew well here until attacked by the 
wilt disease. To all appearances neither the cotton nor the wilt fungus was 
affet^teil by this very heavy application, which was on a rather small plot (3.")0 
square feet). 

6. Copper carbonate, applied in solution to the soil just before planting, at the 
rate of 136 pounds per acre. 

7. Copper acctatf, applied in solution to the soil just before planting, at the 
rate of 102 pounds per acre. 

8. Lime (fresh stone lime) was applied to infected land in September. 1899, at 
the rate of 3, 4, 5, and tons per acre. The lime was harrowed in as soon as it 
had become slacked. An equal area was left untrea ed, and cotton was planted 
in the usual way in 1900. Lime was also applied to other infected fields in the 
spring, shortly before planting, at the rate of 3.000 and 4.00:) pounds per acre. 

9. Sulj>linr (flowers of sulphur) was applied to the soil before planting, at the 
rate of 400 and 600 pounds per acre, 

10. Lime-sulphur mixture, consisting of 30 pounds of lime, 30 pounds of sul- 
l)hur. and 00 gallons of watrr. The lime was slackcnT and boiled with the sulphur 
one hour. It was applied at the rate of 6i)0 and 9it0 gallons per acre. 



10 

11. Lii'er of suljiJiur. applied in solution before planting, at the rate of 30 pounds 
per acre. 

12. Iron sulphate, applied in solution before planting, at tiie rate of 100 pounds 
per acre. 

13. Carholic acid, applied at the rate of 12 and 18 gallons of crude acid per acre. 

14. Caustic soda, applied in 8 xjer cent solution at the rate of 1 ,000 pounds of com- 
mercial caustic soda per acre. 

15. Formalhi, applied in 10 per cent solution at the rate of 100 pounds of the 
commercial (40 per cent) formalin per acre. 

16. Kainit, used at the rate of 2,000 and 4,000 pounds per acre. 

For the purpose of comparison, in all cases, untreated plots were left beside those 
subjected to the foregoing treatments. The wilt disease was very bad on these 
fields, and nearly all the cotton died on both the treated and the untreated plots, 
but no difference traceable to the fungicides used could be observed between them. 

A test was also made of "Brown's Watermelon Wilt Remedy", which 
has been put on the market as a preventive for both the cotton and 
the watermelon diseases. This treatment consisted in soaking the seed 
twenty-fonr hours in a patent compound/ with the addition of a small 
amount of air-slacked lime to tlie soil before planting. It was given 
a careful trial, according to the directions of the maker, but no differ- 
ence was observed between the treated plots and the untreated plots 
beside them. 

At the request of the Department, the same remedy was tested on 
watermelons by Mr. T. S. Williajns, of Monetta, S. C, a well-know^i 
grower of melons, who has had much experience with the watermelon 
wilt disease. The seed for 2U( ) hills Avas treated according to directions, 
and 200 other hills beside them were left untreated. A perfect stand was 
obtained, and the plants were thinned out to one in a hill. A careful 
count sixty-five days aftei' planting showed 195 ot the 200 treated plants 
killed by the wilt disease. In the other (untreated) row 187 of the 
plants were killed by the fungus. 

PREVENTIVE MEASURES. 

HYGIENIC TREATMENT. 

In the cotton Avilt, as in many other plant diseases, certain pre- 
ventive or palliative measures, based on our knowledge of the way the 
disease spreads, are very important. These are as follows: 

(1) Rotation of crops. — Land once infected with this disease has 
never been freed from it. It is important, tlierefore, that such land 
should not be planted for several years to okra or anj^ variety of cot- 
ton subject to this disease. The length of time the fungus will live 
in the soil is not yet determined, but four years' rest lias proved 
insufficient in several cases. Other crops — as corn, cowpeas, cabbage, 
watermelon, etc. — may, it is believed, be planted on this land with 
safety. 

' Stated by the Division of Chemistry, to which samples were submitted, to be 
made of a mixture of liver of sulphur and lime, 



11 

The greatest spread of the wilt disease is by the direct growth of 
the fungus through the soil from diseased to healthy areas. On this 
account an area considerably^ larger than that on which the plants are 
wilting should be included in this rotation. 

(2) Removal of diseased plants. — ^Another important source of infec- 
tion is the diseased jjlants themselves. The fungus produces on the 
dead stems and roots great numbers of spores, which are carried to 
other places in a variety of ways. All diseased plants should be 
pulled and burned as soon as discovered, so as to prevent the disper- 
sion of the fungus spores which will finally cover them. 

(3) Avoidance of spread by cattle, tools, etc. — The writer's observa- 
tions in various places in South Carolina during the past two years 
lead him to believe that cattle grazing in the fields spread the disease. 
They should not be allowed to pass freely from infected areas to 
healthy fields, and it would be better not to pasture such infected 
fields. Tools should be carefully cleaned after cultivating the dis- 
eased land. To insure complete destruction of the spores of the wilt 
fungus, such tools should be scoured clean and then washed with a 
2 per cent solution of formalin or a 5 per cent carbolic acid solution. 

(4) Care of the compost heap. — The fungus is sometimes introduced 
into the barnj^ard and compost heap, so that the manure becomes a 
source of general infection to healthy fields. The utmost care should 
be taken to keej) diseased plants out of the manure, and if there are 
any indications that such plants have found their way into the 
manure, or if any new outbreaks of the disease are traced to the use 
of stable manure, all su.ch- manure and compost should be used on 
land where cotton will iiever be planted. 

There is no objection to the use of stable manure which does not 
contain the spores of the cotton-wilt fungus, but experience has shown 
that in the case of the closely allied watermelon-wilt fungus a l)arn- 
yard once infected will remain so for many years, and that all manure 
taken out of it will be likely to spread the disease. The same is 
probablj' true of the cotton-wilt fungus. 

SELECTION OF RESISTANT RACES. 

The most encouraging results have come from the endeavor of the 
Department to find a race of cotton which can be grown on the infected 
lands. There are always some plants in ever}^ field which resist the 
disea.se to a greater or less extent, and it frequently happens that of 
two plants in the same hill, equally exposed to infection, one will die 
and the other live to the end of the season. All degrees of resistance 
may be found, from plants nearly killed by the wilt disease to those 
entirely healthy. The latter are comi^arativelj^ uncommon, however. 

Difi'erent races of cotton vary considerablj^ in their susceptibility 
to the wilt disease. This was shown by an experiment can-i(>d out by 
the Department on the fai-m of Mr. H. L. Galloway, at Dillon, S. C. 



12 

Twenty races, including the more loroniinent ones in cultivation, were 
planted in a field that was thoroughly infected with the wilt disease, 
and their comparative resistance determined in August by counting 
the number of plants remaining healthy, those partiallj'' diseased, 
and those killed. 

None of the races tested were entirely resistant, but some showed 
great promise in this regard. The greatest resistance was shown b}' 
tlie Egyptian cottons, Mitafifi, Abbasi, and Jannovitch, which with- 
stood the disease to a very marked extent. Very few plants Avere 
killed outright, although nearl}^ all were considerablj^ reduced in size 
and yield. The striking difference in resistance between these sorts 
and an ordinary- upland cotton (King) is shown in PI. II, fig. 1. The 
race figured here, the Jannovitch, was imported from Egj-pt hy the 
Department through Messrs. Barbour Lathrop and D. G. Fairchild. It 
is a long-staple cotton of fine quality, said to be the result of a cross 
between the Egyptian and sea island cotton, and regarded as being 
adapted to upland culture. It has been widely distributed during the 
past year, and promises to be of great value. The other Egyptian 
sorts, Mitafifi and Abbasi, which were introduced at the same time as 
the Jannovitch, were also verj^ resistant. They differed from that sort 
chiefl}^ in the yield and the color of the lint. The most productive 
strain of Egyptian cotton grown on infected land w^as Mitafifi, No. 3992. 

Sea island cotton, although closely related to the Egyptian, suffered 
very much. It was practically' no more resistant than the upland 
cotton growing beside it. Nearly all the upland races proved very 
susceptible to the disease, though there were minor variations wiiicli 
must have been due to varietal differences. 

One race only, the Jackson (Limbless), showed a marked resist- 
ance. In this respect it far surpassed all other upland cottons and 
nearly equaled the Eg^qitian. (See PL II, fig. 2.) The yield of this 
race on wilt-infected land was very good. Many plants were injured 
by the disease, but many others were exceptionally vigorous and 
there is no doubt that selection from these healthy plants would 
greatly increase the percentage of resistance. The relative resist- 
ance of these races in the experiment mentioned is shown in the 
following table : 



Table showing varietal resistance of cottons to the wilt disease. 

[The figures denote the comparative resistance of the different races on a scale of one thou- 
sand.] 



Jannovitch . _ . 565 

Mitafifi (average of 3 strains) 559 

Ahhasi _ 479 

Jackson . ^ 453 

Sea island 233 

Eldorado 227 

Texas Wood 162 

Doughty 148 

Hawkins Prolific 142 



Brady 127 

Cook's Long Staple 124 

Excelsior ... 104 

Drake . . 90 

Jones 88 

King . 83 

Peterkin 71 

Truitt ... . 71 

Russell 55 



13 

It will be seen that some of the best kinds are among those most 
injured by this disease; but there were one or more plants in each 
race that entirely withstood the disease, and the seed from these has 
been saved with the intention of securing valuable resistant strains 
by cross-breeding them. 

The ability of certain cotton plants to grow on infected land is due 
to the fact that the wilt fungus is unable to enter their principal root 
system and not to any lack of infection. This has been determined 
by microscopic examination. That infection of these plants has 
really taken place may be demonstrated by an examination of their 
roots for the little tufts of rootlets which mark the location of infec- 
tions (see p. 8). The roots of plants taken from the row of Janno-. ' 
vitch cotton shown in PI. II, fig. 1, were attacked by the fungus in 
over a hundred places, as found by actual count, yet in no case did 
the parasite penetrate as far as the main stem, while plants of King 
cotton in the adjoining row were completely overcome. A part of 
tlie root system of one of these resistant plants is represented in PI. 
Ill, fig. 1. As determined by numerous microscopic examinations 
each little tuft of roots marks a point attacked by the fungus, so that 
there can be no doubt of the thoroughness of the infection and, fur- 
thermore, no doubt that such plants are actually resistant to the 
fungus. 

It is evident that such an effect as the fungus has produced here 
must injure the plant considerably and -this was found to be the case. 
The average height of plants grown on the infected land was 23 inches, 
while plants on adjoining land very slightly infected grew 42 inches 
high. Plate III, fig. 2, shows the difference between these plants. 
Such injury as this would of course greatly shorten the crop, but the 
indications are that seed selected from the most vigorous plants will 
be more resistant than the average. The best plants in our experi- 
mental plots on the infected land were nearly equal to those grown 
on healthy land and also showed a smaller number of root tufts. 

In this connection the most important question is whether this 
quality of resistance to disease is transmissible through the seed to 
succeeding generations. An experiment designed to settle this point 
proved a remarkable success. It was carried out by Mr. Elias L. 
Rivers, of James Island, S. C, who selected a healthy plant of sea 
island cotton that gi-ew in a badly blighted field in 1800. The seed 
from this i-esistant plant was saved and planted in a single row through 
a field, that luul been infected with the wilt disease for several years. 
The adjoining i-ows were planted with seed from his main crop, grown 
on noninfected land. The result is indicated in the photograph (PI. 
IV) taken September, 1000. The wilt disease made almost a clean 
sweep through the oi'dinary cotton, 95 per cent of the plants l)eing 
killed, Avhile in the row planted with seed from the resistant plant not 
a single plant teas killed by IJie wilt disease. 

These plants were vigorous and productive. The dwarfing noted in 



14 

Egyptian and upland cotton grown by the writer on infected land at 
Dillon, S. C, was not so marked here. The quality of the lint was 
good, though not equal to the crop from which the selection was made. 
It ishelieved, however, that by continued cross breeding and selection 
in succeeding years the qualitj' of the cotton maj^ be improved with- 
out loss of resistance to the wilt disease. Work along this line has 
alreadj^ been started in a small way by the Department, Avhicli it is 
hoped may be enlarged. 

It has been shown that much can be accomi3lished in the control of 
the wilt disease of cotton by simply selecting seed from resistant 
plants. It is very probable that better results will be obtained bj^ 
cross-breeding these resistant individuals, for in this way the resist- 
ant qualities of two plants will be combined and there will be added 
the increased vigor wiiich usually comes from crossing. On the other 
hand, if the flowers of a resistant cotton plant should be fertilized by 
pollen brought by insects from a diseased plant, as may easily happen 
in the field, plants grown from the resulting seeds will very likely be 
less resistant than if they had been fertilized by pollen from another 
resistant plant. On this account, in the selection of resistant races, 
it will be desirable to cross by hand as many flowers as possible in 
order to increase the chances of success. 

In connection with tlie M^ork of the Department a large number of 
crosses between resistant plants have already been made. It has been 
our aim to secure resistant strains from our common races by 
cross-fertilizing plants of the same race, and at the same time to 
increase the productiveness and improve the quality bj^ selecting the 
best plants of each sort for breeding. 

The fact that the Egyptian cottons are resistant to the wilt disease 
has led to the attempt to produce a resistant long-staj)le ui^land cotton, 
by hybridizing resistant plants of the common upland races with the 
Egj'ptian cotton. It is very desirable that ever3''one who undertakes 
the breeding of resistant cotton should at the same time pay great 
attention to securing a more productive race and a finer quality of 
staple. 

CONTROL OF OTHER WILT DISEASES BY SELECTION. 

The indications are that other diseases similar to the cotton wilt 
may also be controlled by the selection of resistant races. 

The wilt of the cowpea, which is a troublesome disease in many 
parts of the South, is caused bj' a fungus closely allied to that pro- 
ducing the cotton wilt {Neocomospora vasinfecta var. iracheiijliila). 
In this case we already have a race, known as Little Iron, which will 
grow on infected land. A fine crop of this pea was groAvn during the 
past season by Mr. T. S. Williams, of Monetta, S. C, on fields where 
the whole crop was lost last year and where other races planted 
alongside it this year have been practically ruined. 



15 

Further investigations will probably I'esult in the discovery of other 
races of cowpeas which may be so improved by selection that they 
may be planted on land infected by the wilt disease. 

The wilt disease of watermelons, also allied to the two preceding, 
may prove amenable to the same treatment. The Department has 
under way some experiments to determine the possibility of finding 
a race of watermelon which may be grown on infected land. This 
would be exceedingly desirable, for this disease has made the growing 
of melons for market impossible over large areas in the South which 
formerly produced them in great abundance. 

CONCLUSIONS. 

There is great promise of a successful i-emedy for the cotton-wilt 
disease in selection of seeds from healthy plants growing on infected 
soils and by continuing to select and cross-breed the most resistant 
plants in succeeding crops with a view both to resistance and quality 
of staple. 

It would be well in the case of upland cotton to start with a race 
like the Jackson, which is already highly resistant, and improve and 
fix the quality by careful cross breeding and selection. In places 
where this cluster type of cotton is undesirable a resistant strain of 
the sorts commonly cultivated can probably be obtained by cross 
breeding and selection. It is hardlj^ to be expected that this process 
will result in a perfectly immune race the first year. Even though 
much of the cotton become diseased, the selection should be con- 
tinued each succeeding year until the quality of resistance is fixed. 

In the case of the sea island cotton, where length and fine quality 
of staple are essential, the process of selection and breeding should 
l)e the same. Resistance to disease must be the primary requisite, 
and from the resistant plants those bearing the finest lint may be 
selected. , 

The Egyptian cottons will i^robably prove of the greatest value when 
crossed with our ui)land races so as to add the vigor and quality of 
the former to the productiveness of the latter. It is hoped that the 
Depai-tment will be able to extend its work along this promising line. 

In addition to selection for resistance, all practicable ijreventive 
measures should be applied. Rotation of crops is even more impor- 
tant on these infected soils than on healthy ones, for the continual 
growing of cotton on these lands will increase the amount of disease 
and decrease the resistance of the cotton. 

Prompt destruction of diseased plants is also very important. 
Every effort should bo made to avoid the infection of healthy fields 
l)y anijnals, tools, wash watei- from diseased fields, diseased plants, 
infected compost, etc. As already stated, land once infected with 
this disease reniains infected lor an unknown period. 



16 

EXPLANATION OF PLATES. 

Plate I. Fig. 1. — A field of ordinary upland cotton at Dillon, S. C, showing 
the damage caused by the wilt disease (photographed in August. 
1900). Fig. 2. — Field of healthy upland cotton adjoining the in- 
fected field shown in fig. 1 (piiotographed in August, 1900). 

Plate II. Comparative resistance to wilt disease of different races of cotton in 
experimental plots of Division of Vegetable Physiology and Pathol- 
ogy, on the farm of Mr. H. L. Galloway, at Dillon, S. C. (photo- 



graphed August, 1900) : 



Fig. 



1. — Jannovitch, an Egyptian cotton, on 



the left, and King, a common upland race, on the right. Fig. 
2. — Jackson, on the left, and Drake, on the right. These plots were 
planted at the same time and treated exactly alike. 

Plate III. Fig. 1. — Root tufts produced by partial infection of resistant plants. 
The roots figured here were from a jjlant of Jannovitch c tton taken 
from the row shown in PI. II. fig. 1. There were about one hundred 
and fifty of these little tufts on this root. (Drawn by Mr. W. R. Scholl, 
from a root collected in September, 1900. ) Fig. 2. — Egyptian cotton 
plants, showing the dwarfing effect of numerous partial infections 
of the small roots. The plant at the left came from noninfected soil 
and is healthy, while that at the right grew on infected land near 
by. (Drawn by Mr. W. R. Scholl. from a photograph.) 

Plate IV. Sea island cotton resistant to the wilt disease {photographed Septem- 
ber, 1900, on the plantation of Mr. Elias L. Rivers, James Island, 
S.C). The row in the foreground was planted with seed from a 
single healthy plant that grew in infected land the year before. 
The adjoining rows, now almost entirely killed by the wilt disease, 
were planted with seed of the ordinary, fine sea island cotton. 
There are a few scattered plants in these rows that have resisted the 
disease. It was from such a plant as these that the seeds planted in 
the middle row were taken. 



o 



Bui. 27, Div. Vcg. Phy3. & Path., U. S. D^M. of Agriculture. 



Plate I. 




Fig. 1.— Wilt Disease in Upland Cotton Dillon, S. C 




Fig. 2.— Healthy Field of Upland Cotton, Dillon, S. C. 



Bui, 57, Div. Veg. Phys. & Path., U 5, Dept, of Agriculture. 



Plate II 




Fig. 1 .— Jannovitch, an Egyptian Cotton, on the Left; King, an Upland Cotton, 
ON THE Right, Showing Comparative Resistance to the Wilt Disease. 




BP';. ^ ' ■. 






\f> 




*»*•■ ■" 




.^.ifc 



'r 



^: 






4.. 




Fio. 2.— Jackson on the Left, Drake on the Right, Showing Comparative 
Resistance to the Wilt Disease. 



Bui. 27, Div. Veg. Phys & Path , U. S. Dept, of Agriculture. 



Plate II 




Fig. 1.— Root Tufts Produced on Jannovitch Cotton by Repeated Partial 

Infections by the Wilt Fungus. 




Fig. 2.— Egyptian Cotton Plants from Infected and Noninfected Soil, Showing 
Dwarfing Effect of the Wilt Fungus. 



Bui 27, Div. Veg, Phys & Pcth , U. S. Dept. of Agriculture. 



Plate IV. 




Bulletin No. 28. 



V. P. P.— 82. 



U.'S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 
ALBERT F. "WOODS, Chief. 



THE CULTURAL CHARACTERS 



OF 



PSEUDOMONAS HYACINTHI, Ps. CAMPESTRIS, Ps. PHASEOLl AND 

\\ STEWARTI-FOIIR ONE-FLAGELLATE FELLOW 

lUfTERIA PARASITIC ON PLANTS. 



BY 



ERWIN F. SMITH, 
Paf/io/q^isf, ill C/iar^t' of Laboratory of Plant Pathology. 



Issued August 6, 1901. 





OTANi 
RD& 



WASHINGTON: 

COV K RN M K N r I'RIN'JINC OFFICE, 

I y o I . 



OFFICE OF PLANT INDUSTRY. 

}). T. (taI;T>(i\vay, THrtclor. 
AFFILIATED DIVISIONS. 

Gardensi and Grouivh, B. T. Galloway, Superintendent. 

Vegetiifde Physiology and PatJioIogy, Albert F. "Woods, Chief. 

Agrostology, F. Lamson-Sc;kibner, Chief. 

Pomology, G. B. Brackett, Chief. 

Section of Seed and Plant Introduction, Jared G. Smith, Chief. 



DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY, 



SCIENTIFIC STAFF. 

Albert F. Woods, CJiief of Division. 
Merton B. Waite, A.'ifiistant Chief. 

associates, 

Erwin F. Smith, AVm. A. Orton, 

Newton B. Pierce, Ernst A. Bessey, 

Herbert J. Webbbr, Flora W. Patterson, 

M. A. Carleton, HeriMan von Schrenk,' 

P. H. DoRSETT, Marcus L. Fi-oyb,^ 

Thomas H. Kearney, Jr. 

IX cnARGK OF t,aboratokies. 

Albert F. Woods, Plant Phy.siology. 
Erwin F. Smith, Plant Pathology. 
Newtox B. Pierce, Pacific Comt. 
Herbert J. Webber, Plant Breeding. 



1 < 



' Special agent in oliarge of studies of forest-tree diseases, cooperating with tlie Division of Forestry, 
v. S. Department of .\griculture, and the Henry Sliuw School of Botany, St. Louis, Jfo. 
'-))etailed as tol^aeeo expert, Division of Soils. 



Bulletin No. 28. ^'- ^'- 1'-— ^-• 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 
ALBERT F. WOODS, Chief. 



THE CULTURAL CHAK.ACTERS 



OF 



PSEUDOMONAS llYAflNTHl, Ps. CAMPESTRIS, Ps. PIlASEOLl AND 

PS.STEWARTI-FOUR ONE-FLAGELLATE YELLOW 

BACTERIA PARASITIC ON PLANTS. 



BY 



ERWIN F. SMITH, 
Pathologist^ ill Charge of Laboratory of Plant Pathology. 



IssuKD August 6, 1901. 




WASHINGTON: 

G O V K R N .M E N T " P R I N T I N G OFFICE. 
I 9 O I . 



LETTER OF TRANSMITTAL. 



U. S. Department of Agkiculture, 
Division of Vegetable Physiology and Pathology, 

Was/mu/ton, D. C, January 15^ 1901. 
Sir: I have the honor to transmit herewith the manuscript for a 
bulletin \)\ Dr. Erwin F. Smith, of this Division, on the cultural 
characters of Pseudmnonas hyacintlil^ Pi^. campestris, Ps. 'phaseoli., and 
Ps. stewarti — four one-flagellate yellow bacteria parasitic on plants. 
The first is the cause of a serious disease of hyacinths, described in 
Bulletin No. 26 of this Division; the second is the cause of a widely 
distributed and destructive disease of cabbages, known as brown rot 
and described from a practical standpoint in Farmers' Bulletin No. 68; 
the third is the cause of a serious disease of beans, and the fourth is 
believed to be the cause of a serious disease of sweet corn. The Bul- 
letin also contains occasional references to Bacilhis amylovrnnis, B. coli 
and other bacterial organisms which were used for comparison. It is 
the first exhaustive working over of an interesting group of plant 
parasites, concerning which practicall}'^ nothing was known in 1896 
when Dr. Smith began his studies. The work described is of a purel}^ 
technical nature, but will be valuable to those in experiment stations 
and elsewhere who are engaged in investigating the bacterial diseases 
of plants. I respectfully reconuuond that the paper be published as 
Bulletin No. 28 of this Division. 
Respectfully, 

Albert F. Woods, 

Chief of I))V)i<i()ii. 
Hon. James Wilson, 

Secretary of Agriculture. 



CONTENTS. 

Page. 

Introduction 7 

Growth in fluid media 9 

Alkaline beef broth 9 

Acid beef broth 11 

Salted beef broth 12 

Acid vs. Alkaline beef broth . -. 14 

Uschinsky's fluid 18 

Milk and litmus milk 18 

Growth on solid media 20 

Loeffler's solidified blood serum 20 

Nutrient gelatins 21 

Nutrient agars 29 

Potato 33 

Coconut 35 

Kadish 36 

White turnip 37 

Yellow turniij 38 

Rutabaga 40 

Carrot 41 

Sweet potato 43 

Sugar beet 44 

Sensitiveness to acids 46 

Acid beef Ijroths 46 

Lactic acid 48 

Potato broth 48 

Malic acid 49 

Cabl)age juice .' 50 

Tomato juices 51 

Hyacinth broth 52 

Feeble diastasic action 54 

Iodine starch reaction 55 

Growth on jiotato with addition of cane sugar 56 

Growth on potato with addition of maltose and dextrine 56 

Growth on potato with addition of diastase of malt 57 

Potato starch in peptone water with diastase 57 

Nutrient starch jelly No. 1 59 

Nutrient starch jelly No. 2 63 

Hyacinth starch jelly 64 

Aerobism 65 

Fermentation tubes 65 

Growth in nitrogen 72 

Growth in vacuo 76 

Growth in hydrogen 79 

Growth in carbon dioxide 83 

3 



Page. 

Relative nutrient value of carbon compounds 85 

Bouillon and peptone water with various sugars, etc 85 

Crude vegetable substances 86 

Sugar gelatin - 87 

Sugar agars 87 

Sodium acetate ■ 96 

Nutrient starch jelly with sugars, gums, and alcohols 96 

Temperature experiments 98 

Thermal death point - 98 

Maxinuim temjierature for growth 102 

Optimum temperature for growth - 108 

Minimum temperature for growth 108 

Formation of acids 109 

Formation of alkalies HO 

Rosolic acid test HO 

Acid fuchsin test - - - 113 

Litmus 114 

Reduction experiments 114 

Methylene blue 114 

Indigo carmine. 115 

Litmus 11" 

Tests for hydrogen sulphide 127 

Formation of indol 128 

Tests for nitrites - 129 

Peptonized beef broths ' 1 29 

Peptonized Uschinsky's solution 129 

Nitrate bouillon 129 

Ferments - 130 

Cytase - 130 

Invertase 132 

Diastase 133 

Trypsin 134 

Lab ferment 134 

Oxidizing enzymes 134 

Pigment studies 136 

The yellow color 136 

The brown pigment 140 

Nature of the cell wall 143 

Vitality 144 

Length of life in culture media 144 

Resistance to dry air 145 

Resistance to sunlight 147 

Resistance to heat 148 

Resistance to acids 148 

Resistance to alkali 148 

Growth in presence of calcium sulphite 148 

Growth over chloroform 148 

Means of distinguishing the four species of Pseudomonas. . - 149 

Remarks on the yellow Pseudomonas group 152 

Characters in common 152 

Other spe(!ies belonging to this group 153 



ILLUSTRATION. 



Page. 

Fig. 1. — (a) Evolution of gas on adding liydro'gen peroxide to potato culture 
of Ps. phaseoli. 
(b) Uninoculated tube to which hydrogen peroxide has been added . . 135 

5 



The Cultural Characters of Pseudomonas hyacinthi, Ps. campes- 

TRIS, Ps. PHASEOLI, AND Ps. STEWARTI, FoUR OnE-FlAGELLATE 

Yellow Bacteria Parasitic on Plants. 



INTRODUCTION. 



The morphology and pathogenic properties of Pseudomonas hya- 
cinthi were described by Wakker in 1S83-18S9,' and were redescribed 
by the writer in 1897 in Proceedings of the American Association for 
the Advancement of Science,' and in 1901 in Bulletin No. 2G of this 
Division.^ 

The morphology, cultural characters, and the pathogenic properties 
of Pseudomonas campestris were first established by Pammel (in part), 
in 189p* and were more fully described by the writer in 1897'^ and 
1898.*"' In 1898 they were described also by RusseH and Harding,^ 

1 (1) Yorlaufige Mittheilungen iiber Hyacinthenkrankheiteu. Botanisches Cen- 
tralblalt, Bd. XIV, 1883, pp. 315-316. (2) Het geel-of nieuwziek der Hyacinthen 
veroorzaakt door Bacterium HiiachithiAYsikker. Onderzoek der Ziekten van Hya- 
cinthen, en andere bol-en knolgewassen. Verslag over het jaar 1883. Haarlem, 
August, 1884. 8vo, pp. 4-13. (3) Onderzoek der Ziekten van Hyacinthen, en 
andere bol-en knolgewassen. Verslag over het jaar 1884. Haarlem, May, 1885. 8vo, 
pp. 1-11. (4) Onderzoek der Ziekten van Hyacinthen, en andere bol-en knol- 
gewassen. Verslag over het jaar 1885. Haarlem, May, 1887. Kvo, pp. 1-5 and 27- 
37. (5) Contributions a la pathologic vegetale: 1. La maladie du jaune ou nialadie 
nouvelle des jacinthes, causee par le Bacterium Hyacinthi. Archives neerlandaises 
d. Sci. ex. et nat.. Tome XXIII, 1889, pp. 1-25, pi. 1. 

'"Wakker's Hyacinth Bacterium. Proceedings of the Amer. Assoc, for the Adv. of 

Sci., 1897, p. 274. 

'■* Wakker's Hyacinth Germ, Pseudomonas hyacinthi (Wakker)._ Washington, Gov- 
ernment Printing Office, 1901, pp. 45, 1 pi., 6 text figs. 

^Bacteriosis of RutaV)aga (Barillns campestris n. sjj.). Bull. No. 27, Iowa Exp. 
Station, Ames, Iowa, 1895, pp. 130-135. 

5(1) Science X. S., Vol. V, June, 1897, p. 963. Abstract of a paper read before the 
Biological Society of Washington, May, 1897. (2) Pseudomonas campestris (Pam- 
mel). The cause of a Ijrown rot in cruciferous plants. Centralbl. f. Bakt. 2. Abt., 
Bd. Ill, July, August, and September, 1897, pp. 284, 408, 478, 1 pi. 

« (1) The black rot of the cabbage. U. S. Dept. of Agr. Farmers' Bulletin No. 68. 
Jan. 8, 1898. (2) Additional notes on the bacterial brown rot of cabbages. Bot. 
Gaz., vol. 25, pp. 107-108. Amer. Nat. No. 32, p. 99. Both abstracts of a paper 
read before See. for Plant Morphology and Physiology in December, 1897. 

"A bacterial rot of cabbage and allied i>lants. Wis. Exp. Station Bull. No. 65, 
Feb., 1898. (Issued in March.") 



8 

and by Kussell.^ More recently Harding- has shown that the disease 
produced b}' this organism occurs in ca))bage in various places in 
Europe;^ and Hecke has demonstrated its occurrence in Kohlrabi in 
southern Austria.^'' 

Pseudomonas 2>haseoli was described briefl}' and named bj' the writer 
in 1897,^ after securing numerous infections with pure cultures. The 
disease which it produces had been previously ascribed to bacteria by 
Beach/ and by Halsted,^ as the result of a microscopic examination, 
but the organism itself had not been described, nor had it been shown 
by means of pure culture inoculations to what organism the bean dis- 
ease was due. Quite recently the same or a very similar organism has 
been described briefly by Delacroix, who obtained it from diseased 
beans in fields near Paris." 

Pseudomonas steicarti was found in sweet corn and described in 1897 
by Stewart," who. however, established its pathog-enic nature only 
inferentially. It was named with some additional characterization by 
the writer in 1898 from a culture furnished by Mr. Stewart for that 
purpose.- Doubt still remains as to its pathogenic properties, and 
must continue until the disease has been produced with pure culture 
inoculations from this particular species and under conditions preclud- 
ing its origination by any other organism. Of the existence of a dis- 
ease of maize due to bacteria no one who has examined specimens from 
Long- Island or elsewhere can have a moment's doubt. The question 
as to what species causes it can be settled definitely only by successful 
pure culture inoculations. 

The following pages were originally intended to form part of Bulle- 
tin 26 of this Division, but the manuscript grew to such an extent 
under ui}' hands, and came to include so many references to related 

'A Ijacterial disease of cabbage and allied plants. Proc. 11th, An. Conv. Amer. 
Col. and Exp. Stations, \u 86. (Issued in March, 1898.) 

•^ Die schwarze Fiiulnis des Kohls und verwandter Pflanzen, eine in Europa weit 
verbreitete bakterielle Pflanzenkrankheit. Centralbl. f. Bakt., 2 Abt., Bd. YI, 1900, 
No. 10, pp. 305-3i:l 

^^Eine Bacteriosis des Kohlrabi. Zeits. f. das landw. Versuchswesen in Oester- 
reich, 1901, and subsequent letters to the writer. Inoculating from a pure culture 
furnished by Dr. Hecke, the writer has also recently produced the typical brown rot 
in cabbage. 

^ Descrijition of Bacillus phaseoU n. sp. with some remarks on related species. 
Proc. Am. Assoc, for Adv. of Sci. for 1897, pp. 288-290. 

* Blight of Lima Beans. N. Y. Ag. Exp. Station Bull. Xo. 4S, new series, Dec, 
1892, Geneva, N. Y., p. 331. 

^A Bacterium of Phaseolus. Rept. of Bot. Dept. X. J. Exp. Station for 1892, pp. 
283-285. 

"(1) La graisse, maladie bacterienne des Haricots. Comptes Rend us, T. 129, p. 
656. (2) Aunales de I'lnstitut Agronomicpie, T. , p. . 

''A bacterial disease of sweet corn. Bull. 130, Geneva Exp. Station, X. Y. ; also 
16th Ann. Rept. N. Y. Agr. Exp. Station for the year 1897, pp. 401-416. 

* Notes on Stewart's sweet-corn germ, Psoidoinomis .storarti n. sp. Proc. Am. Assoc, 
for Adv. of Sci. for 1898, pp. 422-426. 



9 

organisms, that, finally, it was decided to add still more references of 
thL character and to publish it separately, making this bulletin, as far 
as possible, a monographic or comparative study of the. cultural char- 
acters of the yellow species of Pseudomonas parasitic on plants. This 
statement will serve to explain the arrangement of the text. Under 
each sul)head 2\ hyacinthi is the organism lirst considered, but when- 
ever comparative studies have made it possible statements are added 
respecting the Ijehavior of related species. Occasionally mention is 
made of species not closely related, e. g. Bacillus amylovonis, B. coli^ 
B. carotovorus, and at the end I have noted some other species which 
belong to this group of bacteria, and which I have here designated The 
YELLOW Pseudomonas group. 

Some particulars have not been worked out as thoroughly as could 
be wished, e. g., (1) the relative nutrient value of nitrogen compounds, 
(2) the effect of antiseptics and germicides, but on the whole it seems 
l)est not to give any more time at present to these particular organ- 
isms, the main features of whose morphology and physiology have, it 
is believed, been made out correctly. 

GROWTH IX FLUID MEDIA. 

Alkaline Beef Bkoth. 

In test tubes of Weber's resistant glass, containing 10 c. c. of 1:2 
alkaline beef broth ^ the fluid always showed a feeble clouding in 48 
hours when inoculated with a 2 mm. loop from a fresh fluid culture of 
Ps. hyacinthi and kept at 23^ C, or thereabouts. Also, when the 
tubes were inoculated with a much smaller number of germs, viz, as 
few as could be transferred from a fluid culture on the extreme tip of 
a platinum needle, the clouding always followed, being a little delayed 

1 This beef broth (stock 286b) was made as follows: Into a large beaker of Jena 
glass I put 1,100 grams of finely minced lean beef, covered it with 1,500 c. c. of distilled 
water (from a tin-lined copper tank), and set into the ice chest for 21 hours. The 
mixture was then strained as dry as possiltle through a clean towel which had been 
thoroughly washed in distilled water before using, an additional 800 c. c. of distilled 
water having been added previous to the straining. The result was 2,350 c. c. of red 
acid fluid. This was put into the steamer, warmed up to 100° C, and left at that 
temperature 45 minutes. • It was then filtered thnjugh S. and S. paper, yielding when 
cold 2,000 c. c. of clear, pale, yelUiw fluid. This was then made up to 2,200 c. c. by 
adding distilled water. After thorough mixture of the broth and water by pouring, 
samples <>f the fluid were titrated against caustic soda, using jihenolphthalein as indi- 
cator, 10 c. c. requiring 2.5 c. <•. of — XaOH to exactly nentralizi' it. A fermentation 

tube filled at this time (25 c. c of fluid) and aftei-wards inoculated witli PxiriUvs 
cloacic yielded 2 to 3 c. c. of gas, indicating the ^jresence of muscle sugar. This acid 
fluid was designated 286a. To ol)tain stock 286b, 600 c. c. of this fluid was rendered 

exactly neutral to phenolphthalein by adding 7.5 c. c. of ^NaOH. On eteamnig 

one-half hour a slight precipitate came down. On filtering again the broth ;vas i)er- 
fectly clear and remained so. It gave a strong blue reaction with neutral litnuis 
paper. 



10 

but in no way restrained. The importance of this fact will be apparent 
a little later when we come to discuss the effect of acid broths. 

On the fourth da}", in this alkaline beef broth, Ps. liyaclntln showed 
a small amount of yellow precipitate. On the 6th day there was less 
precipitate than in tubes of acid beef broth (stock 286a) 11 days old, 
but it was yellower. The clouding was so slight that a penholder was 
easily visible behind a thickness of two tubes. 

On the eleventh or twelfth day there was more of the yellow pre- 
cipitate than on the sixth, but it was not copious. Rolling clouds were 
visible on shaking, but no zoogloeBe, There was no pellicle, but now 
for the tirst time a feeble rim of germs was lo be seen on the wall of 
the tube at the surface of the fluid. Under a Zeiss hand lens (X 6 
aplanat) this rim appeared as a pale amorphous membrane thickly set 
with a series of roundish colonj^-like aggregates, which were white or 
yellowish, and which did not dissolve when shaken down into the fluid. 
Four days later the largest of these colony-like bodies were distinctly 
yellow, the smaller ones being white. On the twentieth da}" the fluid 
was uniformly clouded; there was no pellicle, pnd no ragged zoogloeas 
were visible to the naked e3'e. The bright yellow precipitate on the 
bottom of the tube now covered a diameter of only 1 mm. The rim 
of germs was broad and iilmy. It easily jarred off in large fragments, 
or as a whole, and fell to the bottom. It contained a great many 
zoogloeaB set at regular intervals in what still looked under a X 6 Zeiss 
aplanat like a homogeneous membrane. The upper, larger, and older 
aggregates were decidedly yellow, and set so closely as to form a yellow 
border on the upper rim of tbe ring, which was exposed to the air. The 
lower, smaller, and younger zoogkea? on this ring were white, this 
part being submerged or bareh" out of the fluid. [Subsequent observa- 
tions showed that these white zoogloea? always became yellow with 
increasing age and size.] The greater part of the clouding was still 
attributable to individual germs, but some small zoogloeas could now 
be seen in it, especially when examined with the hand lens. Under 
the compound microscope (Zeiss 16 mm. and 12 comp. oc.) the zoogloeee 
on the rim looked like small, closely set colonies on an agar plate, i. e. , 
they consisted of roundish, colony -like bodies on a paler, homogeneous 
looking membrane. Stained with gentian violet and examined under 
high powers the homogeneous substratum was seen to be composed of 
slender rods, which were often in short chains of 6 to 12 or more seg- 
ments, the individuals forming the chains being distinct and of the 
same size and shape as those not joined. 

On the thirty-third day there was a moderately abundant yellow 
precipitate, and the color approximated Ridgway's canary yellow. 
The fluid was less cloudy than it had been, but was still uniformly so. 
It was not turbid with zoogloeee, but some small flecks were floating in 
it. There was no pellicle, but an easily detached, pale, fragile, homo- 
geneous rim of germs, which was closely set with small, roundish, uni- 



11 

form -looking-, colon^^-like aggregates. These did not dissolve readily 
in the fluid and all the larger ones were distinctly yellow and easily 
visible to the naked eye. The fluid had shown no acid reaction. It 
was now alkaline, and was not brown.* 

On the fiftieth day the fluid was feebly and uniformly clouded, but 
much clearer than it had been. It was strongly alkaline to litmus; it 
was not ropy; there were no rolling clouds on shaking. There was no 
pellicle. The rim was 6 mm. wide and studded with zoogloea?; the 
largest of these were one-third mm. in diameter and yellow to the 
naked eye; the precipitate was still bright yellow and rather copious. 

On the seventieth da}" the fluid was nearly clear, and there was no 
brown stain in it. It had evaporated from 10 c. c. to about 6.5 c. c. 
Eighteen days later the fluid was entirely clear. 

On the one hundred and nineteenth day there was no brown stain, 
and large irregular crystals were present in the sediment. 

Acid Beef Broth. 

This broth was from the same stock as 286b, but no alkali was added. 

N 
Its acidity was +25 of Fuller's scale, i. e., 25 c. c. of — NaOH would 

have been required to render 1,000 c. c. of this broth neutral to 
phenolphthalein. It was feebly acid to good neutral litmus paper. 
This fluid retarded growth slightly and was distinctly favorable to the 
formation of zoogloete. The precipitate was more copious than in the 
alkaline beef broth and was duller 3'ellow — a dirty Naples yellow. 
The clouding began in about 72 hours, when the inoculations were 
made with large loops from fresh fluid cultures and on the sixth day 
when the inoculations were made with as small a quantity of the fluid 
as could be lifted and seen on the tip of a platinum needle. Notes on 
one of eight cultures in this medium are given below: 

Stock 286a, tube 11, February 4, 1898: Tube of resistant glass containing 10 c.c. of 
broth inoculated at 1 p. m. with Ps. hyacinthi from an alkaline beef broth culture 
(No. 1, January 29), which had been cloudy for three days and contained many 
actively motile germs. Only a tiny drop on the tip of a platinum needle was put into 
the tube, i. e., about 1/50 of a good-sized loop. February 5, clear; February 7, clear; 
February 8, clear. [Tubes exposed to the same temperatures as the alkaline beef 
broths.] Two check tubes of alkaline broth (286b) inoculated in the same way were 
cloudy on the third day. This broth exerts a distinct retarding influence which is 
especially noticeable when the dose of germs is small. 

Feljruary 9. Clear. 

Fel)ruary 10, 2.30 p. m. Very feebly clouded; some whitish flecks (zooglcese) on 
the wall of the tube from top to bottom on one side. 

February 19. Fluid turbid from numerous whitish flecks which are easily visible 

' Throughout this bulletin "acid" and "alkaline" refer to litmus reactions unless 
it is otherwise stated. 



12 

to the naked eye. ( No zoogloe?e visible in the two tulles of 286b held for comparison. ) 
Rim well developed; most of its zooglcefe are white, but a few are yellowish. A pel- 
licle consisting of zoogl<Te?e held together by a film has gone to the bottom. Fluid 
homogeneous and now feebly alkaline to neutral litmus paper; in some of the tubes of 
this set the fluid has begun to clear a little at the top. Precipitate dirty yellow-white 
and rather abundant. 

March 12. Xo new pellicle; fluid uniforndy thin cloudy; no crystals. The zooglcefe 
scattered through the fluid and lodged on the walls of the tube are very numerous, 
i. e., fifty times as many as in the two check tubes of alkaline beef broth. They 
consist of irregular, loose, rather large, whitish or very pale yellow-white flecks; 
rolling clouds are also visible on shaking. The tendency to form zooglteie is much 
stronger in this fluid than in 286b, but they also form in the latter after a time. 
There is a thin rim of germs on the wall of tlie tube for a distance of 3 mm. above 
the fluid; this rim bears several hundred small, roundish, colony-like zooglcpte, most 
of which are now distinctly yellow — all the older larger ones. In the other seven 
tubes of this set most of this rim went down easily as a thin broken film on gentle 
shaking. 'The precipitate on the bottom of the tube covers a diameter of 10 mm. and 
is dull yellow — between wax yellow and Naples yellow. The color of the jirecipitate 
in the check tubes of stock 286b is l)righter, and lies between gamboge yellow and 
chrome yellow.^ The fluid is now plainly alkaline to neutral litmus. 

April 13. Fluid nearly clear, no rolling clouds on shaking; no brown stain; moder- 
ately alkaline to neutral litmus paper. Precipitate more copious and certainly of a 
duller yellow than in the strongly alkaline broth. Rim of germs all of one kind, 
i. e., not contaminated, 6 nmi. wide; all of the zooglceee on it are roundish, Init only 
the older and larger ones are distinctly yellow. 

April 25. The fluid has cleared, and there is no brown stain in it; when boileil, a 
vapor was given off which immediately 1 >lued moist neutral litmus paper. 

Salted Beef Broth. 

To determine the effect of sodium chloride upon J^s. hyacintld the 
following experiment was instituted: Stock 529, which was an ordi- 
nary 1:2 acid beef broth (containing 1 per cent AVitte's peptonum sic- 
cum and one-half of 1 per cent c. p. XaCl). was divided into two 
parts. To one was added an additional 1 per cent c. p. sodium chlo- 
"ride, forminef stock 535; the other half was held as a check. The two 
culture fluids were then pipetted into clean test tubes of resistant glass 
and sterilized by steaming for a few minutes on each of three consecu- 
tive da^'s. After some time the two sets of tubes, each of which con- 
tained exactl}" 10 c. c. of fluid, Avere inoculated at the same time and 
in the same way, i. e., with approximateh' equal numbers of bacteria 
from a well-clouded sugar bouillon culture (No. 6. October 29). Each 
of 6 tubes (3 of each sort) received a 2 mm. loop of the cloudj^ 
broth. The other 6 tubes each received as small a drop of the 
clouded fluid as could be seen distinctly on the end of a platinum 
needle. The experiment began at 3 p. m. November 5, 1899, and the 
subsequent observations were made at about the same time each after- 
noon. The following table, in which denotes ''clear," + "feebly 

^Ridgway's Nomenclature of colors, 1st ed. 



13 

clouded," and ++, '"very feebly olouded," shows the date at which 
clouding- took place in these tixbes, the temperature being the same, 
i.e., IS- to 22^ C: 

Table I. — Showing effect of sodium chloride on J'seudomonas htjacinthi in beef broth. 





Method of 
inoculation. 


cent 

of 

NaCl. 










November- 


- 








No. 

of 
tube. 


Stock. 


G. 


7. 


s. 


9. 


10. 


11. 

+ 


12. 


13. 


14. 


15. 


16. 


17. 


529 


Needle 


0.5 



























1 


529 


Xeedlf 


0.5 














+ + 
















2 


529 


Xeedle 


0.5 

















+ 














3 


535 


Needle 


1.5 





























+ + 




■1 


535 


Needle 


1.5 











! 


























5 


535 


Needle 


1.5 



































+ + 


G 


529 


2 mm. liiop ... 


0.5 











+ 


















7 


529 


2 mm. loop . .. 


0.5 











+ 


















S 


529 


2 mm. loop . . . 


0.5 











+ 


















9 


535 


2 mm. loop . . . 


1.5 























+ + 










.10 


535 


2 mm. loop 


1.5 























++ 


1 
i 

1 






11 


535 


2 mm. loop ... 


1.5 





% 

















++ 








12 



There was a distinct slight retardation in stock 529, owing to the fact 
that no alkali was added to it other than that which was naturally in 
the peptone and perhaps, also, to the 0.5 NaCl which it contained. An 
examination of the table, however, shows that there was a ver3Mnarked 
additional retardation in stock 535, which could be attributed only to 
the excess of sodium chloride. The retarding influence once overcome, 
growth proceeded, e. g., in tube -i clouding was as twice as heavy on 
Novem])er 17 as on November 16, and in tubes 10, 11, and 12 it was twice 
as heavy on November 15 as on November 13. The date on which the 
clouding would have taken place in peptonized beef bouillon free from 
sodium chloride and neutralized to phenolphthalein by means of caustic 
soda is indicated in the table by # (.see page !>). 



14 



Acid vs. Alkaline Beef Broth. 



The following experiments were undertaken in 1899 to determine, 
approximately, the limits of growth of J^s. kyacinfhi in acid and alka- 
line media. As a standard for comparison, I made use of a peptonized 
1:2 beef broth neutralized to phenolphthalein b}' caustic soda, and well 
adapted to the growth of this organism. Portions of this stock were 
then acidified with varjdng quantities of malic acid, and others were 
rendered alkaline to phenolphthalein by an excess of caustic soda. Each 
test tube was of resistant glass, contained exactly 10 c. c. of the fluid to 
be tested, and was exposed to the same temperature. Except —80, all 
were inoculated June 11, from tube 8, May 11, a coconut culture, the 
growth of which had ])een delayed for some weeks in a U tube (nitro- 
gen). Each tube received a very large number of germs and approxi- 
mately the same number, i. e., a scant 2 mm. loop of the fresh yellow 
slime. Except —80, all of the cultures were carried through in 
duplicate. The approximate date of the clouding (temperature 25^ to 
30° C.) is shown in the following table, in which 0, is "clear,'"' +, 
"feeblj^ clouded," and + + , "very feebly clouded." 



15 



Si 



P 



98 
91 



> 9 



Mi. 






Pi 



1) 



^ 


_• 


o 


^ 


'^ 


^ 




o 


X 


o 


X 


p^ 




i' 


T" 


u 


— 


^ 


*- 


o 


^ 


*- 


.' 


..-. 




^* 


^ 


— 


tf 


::: 


^ 




^ 


;^ 


;::^ 


-! 


^ 


































iS 












L' 


^ 




J3 






s 


'^ 

> 


XT. 


f 


ij:x 


^ 






1—1 

+ 






























— 


— 


;::: 


S 


K 








1^=, 




c 


•^ 


^ 


-5 




'P 


s 


X 


1 


o 


o 


"Tir 


'fc^ 


5 




s 




























-^ 


^ 


i^ 


^ 




c3 


If 


u 


— 


• fH 


+J 


P.O 


< 



























^ i> 



S r. 



C &: O 
C OS 

o so--^ 



eS 




S 




-t^ 






ao 






■C 


•n 


— 


i> 


^ 




Ci 




a 


0. 




o 



is M 



c 


^ 


o 




03 


2 




c 








o 


•i-t 


A 


fi 




H 





o So 



a 

"-5 



TT 


^ 




■c 


O 








o 


!^) 






be 


p. 


C P 






^ 


•t.^ 


■^ 




>. 


•s 






ci 


s 


hH 




c 




M 












>. 




o 














hr 










tr 


^ 


c 





+o 



3 
5 



.2 S 



o 



-* 


i) 


CJ 


a 








-J 


lO 




1— ( 




+ 


rr 




i) 






o 


■a 














^ 


o 


T? 


^ 


O 


■d 



o C 






O « 1^ 



-+ 



::= 






:3 



c 



D 



C , 



03 



a. o 
a 



oo oo oo 



.S£e 



S 

s 






+ 






+ 



X 


3 






-tJ 


a 






O 




CJ 


0) 


w 


■o 


^^ 


c 


r' 


o 












o 


XiH 


•«^ 










id 


a: 



Zl-^ 



16 

From this table it would appear that the limits of growth for Ps. 
hyactnthi, under the conditions mentioned, lie between — 20 and — 40 
on the alkaline side (probably near — 35) and somewhat beyond +30 
(probably near H-iO) on the acid side. For a long time I was in 
doubt as to whether any growth had taken place in +30, and it is not 
at all improbable that with the introduction of a lesser number of 
germs — e. g., a loop from a fluid culture — no growth would have taken 
place. 

At the same time duplicate tests were made of a number of other 
bacteria and some of the results obtained are shown in the following 
table. Here, again, the tests were insufficient in number to bring 
out all of the peculiarities of the organisms. For instance, there should 
have been broths with intermediate grades of alkalinity and acidity, 
and for two of the organisms, B. pyocyanens jjericarditidis and B. 
coli, the series should have been extended on the alkaline side to at 
least — 100. I have partially compensated for this by stating how soon 
the clouding appeared in certain of the fluids. In case of Ps. steivarti 
and B. coli the experiments should have been repeated in the +60 
broth, since the growth was in any event feeble, and I was at times in 
doubt as to whether there had been any whatever. The — 80 bouillon 
was inoculated June 13 with 2 mm. loops from fluid cultures 2 days 
old. 



17 



n 




a 







I 


\ 




























d 










































b-t 














H 










































X 


■J 






.^ 


,^ 




C 








- 


^ 


- 


V 


e 








a 


t- 


33 


> 






a 


\ ^ 


^ 


, 1 


■> 






> 


■> « 






? 


J 


1 1— 


; I 


M 


p: 


; 3: 


1 



21788— No. 28—01- 



18 



Uschinsky's Fluid. 



This fluid proved to be a ver}^ poor medium for the cultivation of 
Ps. hyacinthi. If onl}^ a few bacteria were put in, the fluid remained 
clear. If more were put in, growth appeared, but clouding was retarded 
(sometimes as long as 18 days) and was never other than feeble. On 
standing several weeks, there formed a feeble rim, at first white, then 
3'ellow, and a translucent pellicle dotted with roundish 3^ellow zoogloese, 
which became yellower. If the rim or pellicle was shaken down into 
the bottom of the tube while it was still pale, it never acquired any 
deeper yellow. The fluid was never more than feebly clouded. The 
precipitate was bright yellow, but very scanty, amounting at the end 
of a month to a breadth of only 2.5 mm. on the bottom of the tube. 
At the end of '2 months seven-tenths of the original fluid remained. 
It had cleared, was free from an}- brown stain, and contained no 
crystals. 

Very delicate white films and woolly flocculent bodies formed in this 
fluid and never became yellow. Under the microscope these colorless 
shreds and films consisted of enormous numbers of short, slender, 
motionless rods, so united that when the cover glass was jarred the 
mass moved as a whole. At first these bodies were supposed to be 
contaminations. The rods, however, were of the right size and shape 
for Pa. hyacinthi, and w^hen these films and flecks w^ere removed to beef 
broth, potato, or other suitable media only this one yellow organism 
developed. These bodies seemed so remarkable that a year later the 
experiments in Uschinsky's solution were repeated, with, however, 
identical results. Ps. campestris and Ps. phamoU also grew feebly in 
this solution and with retardation, but without the films characteristic 
of Ps-. hyacinthi On the contrary, Ps. deu-arti grew in it for a long 
time, and very copiously. Ps. hyacinthi grew very much better in 
Uschinsky's solution when 1 per cent Witte's peptone was added to it. 
In 3 weeks the growth in this peptonized fluid was 100 times as 
abundant as in the check tubes. 

Milk and Litmus Milk. 

The milk w^as obtained from a clean dairy and its reaction was 
amphoteric. It was used, nearly free from cream, in 10 c. c. por- 
tions, in test tubes of resistant glass. It was sterilized (about 24 
hours after milking) by subjecting it, in wire crates, to streaming 
steam for 15 minutes at 100- C. on each of 1 consecutive days, and 
none of the man}' check tubes ever spoiled. 

Many tubes of milk were inoculated with Ps. hyacinthi at diflerent 
times. All gave the same result. For some time there is no visible 
change other than the formation of a yellow bacterial rim or pellicle, 
or both, with some yellow precipitate. Accompanying this growth 



19 

there is a slowl}^ increasing alkalinity, which is first clearl}^ visible on 
about the third to fifth da}". Toward the close of the first week, or 
during the second week, a ver}^ slow separation of the casein (paraca- 
sein?) takes place. The first visible separation is usually apparent 
about the fifth to sixth or eighth to tenth day in the form of a 
iiiillimeter-deep layer of clear whey on top of the milk, which is still 
entirely fiuid. By the end of the third or fourth week the fine white 
casein has settled so that it occupies onh' about one-half of the fiuid, 
the supernatant whey being pale yellow and transparent. Above this 
whey in old cultures there is always a 5 to 7 mm. wide, dense, bright- 
yellow ))acterial rim on the tube. The casein does not set on the start 
and is never coarse flocculent. It finally becomes packed together in 
the bottom of the tube, but for a long time it consists of tiny separate 
particles which roll over each other easily when the tubes are shaken. 
This precipitated casein finally changes from white to yellowish and 
is slowl}^ redissolved (peptonized). At no time during this precipita- 
tion and re-solution of the casein is there any acid reaction or au}^ 
formation of gas. The whey from such cultures had a slightl}^ bitter 
taste. 

The reaction of the medium is best observed by adding to the milk 
enough litmus water to make it a deep lavender color; i. e., 10 c. c. of a 
saturated watery solution of c. p., blue, dry, lime-free litnuis to 200 c. c. 
of milk. Man}' cultures were made in this medium with exact results. 
During the first 8 or 10 days the blue color very slowly deepens and 
the separation of the casein begins.^ During the next 10 days or so 
the casein slowly settles and is still blue. Su))sequently the litnuis 
becomes more or less reduced, but at no time is there any appearance 
indicating the formation of any organic acid. When the litmus is not 
reduced the whey is pale wine red Iw transmitted light (normal color of 
the litmus), but is not red by reflected light. If after several weeks or 
months of growth such reduced or partly reduced cultures are killed 
by heating for 10 minutes at 56^ C, and are then exposed to the air 
for some weeks, the color of the litmus returns. The undissolved 
casein is now distinctly blue and the whey is not red ))y reflected light. 

Numerous tiny, white, centrally constricted, sheaf-like crystals of 
tyrosin appeared in old milk cultures. Crystalline plates presumed to 
be leucin also appeared. . 

Ps. camjpeHtrw and Px. jjhaseoli both act upon milk and litnuis milk 
in much the same way. Neither produces any acid or gas. Both cause 
a slowly increasing alkalinity in the milk with the separation of the 
casein from the whey 1)}' means of a lab ferment. In both, a i)ortion 
of this casein is redissolved (peptonized) with the formation of tyrosin 
and leucin. I^a. stewarti^ on the contrary, docs not precipitate the 

L 

'In one iiistaiicc whey appeared in two tnlu-K of l)ln(' litmus milk tlic fourtli day. 
See table uuiler lieduction. 



20 

casein or produce any other visible change in the milk, not even after 
several months, although it forms a distinct bacterial rim and a rather 
alnindant l)right yellow precipitate. (For action of this organism on 
litmus in milk, see Reduction.) 

The kind of litmus used with milk sometimes has an iiuportant bear- 
ing on the results obtained, e. g., an acid reaction was ol)tainod when 
P,s. Injacinthi was grown in milk colored with Sharp & Dohme's neu- 
tral solution of litmus, and, as this was the first lituuis used, it might 
easil}' have led to erroneous conclusions had not further experiments 
been instituted with other brands of litnms. This litnms, which is 
very sensitive, keeps indefinitely, and is in use in many laboratories 
in this country, is preserved from deterioration (as I have since learned 
from the manufacturers) by the addition of 12 per cent ethyl alcohol. 
The acid which uniformly appeared in cultures of 1\. hyackitld con- 
taining this litmus was not developed from the milk, but from traces 
of alcohol remaining in the medium after sterilization (see Formation 
of acids and Reduction — Litmus). This acid is volatile and smells like 
acetic acid. In some cases the acid which was produced from the alco- 
hol inhibited the growth of the bacteria ])efore the casein was precipi- 
tated, and this never did separate out (3 months). 

A similar acid reaction was subsequently obtained by cultivating 
Ps. hxjaclntld in blue litmus milk, to which drops of c. p. al)solute 
alcohol had been added. In this case also only a slight amoiuit of acid 
was formed, and it was not visible for some daj^s. In l)oth tubes the 
casein was thrown down by the lab ferment before there was any dis- 
tinct acid reaction. Meth}-! alcohol was also tried in the same litmus 
milk, but no red reaction was obtained (56 days). The lavender-blue 
milk graduall}' became deep blue, and the whey separated slowly from 
the casein in the way already described. Evidently this organism can 
not break up wood alcohol. 

For notes on the behavior in other fluid media, see Fermentation 
tubes, Sensitiveness to acids, Relative nutrient value of carbon com- 
pounds. Reduction of litmus, Formation of alkali, etc. 

GROWTH ON SOLID MEDIA. 

Loeffler's Solidified Blood Serum. 

This medium was prepared from beef's blood in the pathological 
laboratoiy of Johns Hopkins Hospital under the supervision of Dr. 
Simon Flexner. It was solidified in test tubes in 15 or 20 c. c. por- 
tions, in long slants, with about 1 c. c. of fluid in the bottom of the V. 
The medium was in excellent condition for use, the surface being 
moist and the body of the substratum veiy light colored and clear. 
The slant surface of one of these tubes was streaked copiously, on June 
5, from a coconut culture of 7*s-. hyaclnthl 7 days old. Cultures of 
other yellow germs were laid on this medium at the same time, and 



21- 

all were kept in the dark at room temperatures. Daring the first 5 
days the temperature ranged from 23^ to 31° C; during the next 20 
days the range was from 22° to 34° (25° to 3(»'^ mo.st of the time), and 
during the last 6 days, from 29° to 37° C. 

]^,.sult. — On the fifth day Bs. I/i/acmthiHhowed an abundant, smooth, 
wet-shining, l)right-yellow growth the whole length of the slant, and a 
copious yellow precipitate in the fluid. There was no liquefaction, or, 
if any, only the merest trace on one side at the ])ottom of the slant. 
In corresponding tuhes of Ps. ca7n2)estris and Fs. phaseoll there was a 
distinct liquefaction the whole length of the streak. On the seventh 
day there was a slight liquefaction under the streak. This was plainest 
in the lowermost part, but was not one-twentieth as much as in the 
corresponding tubes of Ps. campedris and Ps. phaseoH. On the 
fifteenth day the precipitate continued to be brighter yellow, and 
there was decidedly less liquefaction than in corresponding tubes of 
the two organisms just mentioned. The serum of the long slant 
preserved its normal shape and color very well, even in the air, only 
the middle part and the sides just above the fluid being sunken in and 
dissolved away. On a scale of 10, the abdity of these three organisms 
to liquefy this serum was marked 7, 5, and 2, Ps. phmeoll liquefying it 
most readily and Px. Jnjactntkl, least readily. On the thirty-second 
day the precipitate in the V was 15 mm. wide and 7 mm. deep, and 
was still a trifle yellower than in corresponding tubes oi l*s. campestris 
and Ps. p)haseoU., but the liquefaction was decidedly less. The serum 
under the fluid still preserved much of its original color and was not 
liquefied, free access of air being apparently necessary, in case of each 
of these three orglmisms, to the operation of the chemical changes 
ending in liquefaction. About one-half as much fluid was now present 
in this tul)e as in the corresponding tubes of Ps. campestris and Ps. 
p)haseoli. This fluid was strongly alkaline. 

On the same uiedium Ps. stevxirti made an excellent bright buff- 
yellow growth, ])ut there was no trace of liquefactioii (32 days). 

Nutrient Gelatins. 

Ps. hy<(cinthi grew better on l)eef })roth gelatins made strongly 
alkaline to litmus (neutral to phenolphthalein) than on those which 
received less caustic soda and were feebly acid or feebly alkaline to 
litmus. It grew well, however, in beef broth gelatin first rendered 
neutral to phenolphthalein and then feebly acidulated with malic acid. 
A still better growth was obtained by adding cane sugar to this acid 
gelatin, the best growth of all being with -f 48 and +54 malic acid 
gelatin with the addition of 5 or 10 per cent cane sugar. The compo- 
sition of the three gelatins on which the best growth was obtained is 
given below: 

(1) ^ock «'05.— l.-'iOO \rr. finely niiiKvil lean l)eef; 3,000 c. c. distilled water. 
Mixed and put into a cool box for 24 hours. Then in steamer U hours at 70° to 90" 



22 

C, and finally at 100° C; vSqueezed fluid through a clean towel, and steamed again 
for 1 hour. Filtered through S. & S. paper, flasked, and sterilized forming stock 204. 
Fermentaticjn tul)es of this l)roth (25 c. c.) yielded ahout li c. c. of gas with BaclUus 
cloacx, showing the presence of muscle sugar. 1,700 c. c. of 204+255 gr. gelatin 
(Coignet Pere et Cie gelatine extra) . Gelatin soaked in hroth 1 h hours, then heated 
in steamer to 100° C, cooled, added whites of 6 eggs (previously neutralized with 
c. p. liC'l) to clarify, steamed, filtered, flasked, and steamed, added 17 gr. Witte's 
peptonum siccum, steamed and filtered; 1,500 c. c. of acid fluid remained; when 

titrated with caustic soda, ?>A c c. -rryNaOH were required to exactly neutralize 10 

c. c., using phenolphthalein as indicator; i. e., the acidity was +34. Reduced the 

2N , 
acidity to +25 by adding 500 c. c. of distilled water. Then added 2.-) c. c. y so(ia, 

and steamed, filtered, flasked, and sterilized. The gelatin was steamed as short a 
time as possible on each occasion. This stock contained about 13 per cent of gelatin. 

(2) Malic acid gelatin. — 680 gr. finely minced, lean beef; 1,500 c. c. distilled water. 
Mixed and put into the ice box for 24 hours. Boiled three-fourths hour, filtered, 
cooled to 70° C, added 3 gr. NaCl, 12 gr. Witte's pept. sic, 100 gr. of brown German 
gelatin, and when the gelatin was dissolved the whites of 6 eggs, which were incor- 
porated by repeated pourings. Steamed 40 minutes at 100° C, filtered through 
flannel, and titrated with caustic soda and phenolphthalein — acidity +45. Measured 
out 300 c. c. into each of three flasks and exactly neutralized each to phenolphtha- 

2N 
lein by addition of 6.7 i-. c.-y^NaOH. To one flask was then added 7.8 c. c, to 

another 10.4 c. c, and to the third 11.7 v. c of a malic acid water, 1 c. c. of which 

N 
exactly Ijalanced 13.75 c. c.^ NaOH; i. e., enough acid so that tlie gelatins should 

be approximately +36, +48, and +54 of Fuller's scale. These three acid gela- 
tins were then filtered, tubed, and sterilized by steaming for a few minutes on each 
of three consecutive days. These stocks contained 8 per cent of gelatin. 

(3) Stock ^44c.^2,000 c. c. distilled water, 1,000 gr. lean minced beef, 300 gr. 

gelatin (one-half white French, one-half Imjwn German), 20 gr. Witte's i)eptonum 

siccum. The beef was soaked in 1,200 c. c. distilled water 16t 1 hour, then brought 

slowly up to 65° C. on a water bath with constant stirring, then steamed 1 hour and 

filtered. The gelatin was soaked for a few hours in 1,000 c. c. of distilled water and 

then added to the hot beef broth, along with the peptone. Steamed 45 minutes, 

filtered, added 50 c. c. water to make up the 2,000 c. c. Fluid acid to litmus. Titrated 

N 
with caustic soda, using phenolphthalein as an indicator. 2.85 c. c. — NaOH was 

required to exactly neutralize 5 c. c. of gelatin, i. e., the acidity was +57. 14 c. c. of 

2N 

^NaOH was then added to 500 c. c. of the medium to make stock 244c, which was 

then flasked and sterilized. This stock, which contained 15 per cent of gelatin, was 
not perfectly solid at 24° C. A fermentation tube of the beef broth (25 c. c. ) used 
for this gelatin yielded several c. c. of gas upon inoculating with Bacillus cloacx indi- 
cating the presence of muscle sugar. 

To test the effect of varying grades of alkalinity, stock 2+ic was 
compared with three other portions of the same gelatin to which dif- 
ferent amounts of caustic soda were added, viz, (1) with a gelatin con- 

N 
taining, per liter, 40c. c. less of y NaOH (stock 2-W:a); (2) with one 

containing, per liter, 20 c. c. less of the normal soda solution (244b); 
and, finally, (3) with one containing, per liter, 25 c. c. more of the nor- 
mal soda solution (244d). These gelatins 1 commonly designate, fol- 



2H 

lowing Mr. Fuller's scale' as +^0 gelatin, +20 gelatin, gelatin (neu- 
tral to phonolphthalein), and —25 gelatin. The litmus reaction of 
these gelatins was as follows: +40, feebl}^ acid; +20, very feebly 
alkaline; 0, strongly alkaline; —25, very strongly alkaline. 

As already stated, the best growth of Ps. hyacinthi, when pep- 
tonized beef broth was used, was in the gelatin (stocks 205 and 2-i4:c), 
the next best was in the +20 gelatin. The difference in growth on 
these two gelatins was more striking at first than later on, the organ- 
ism being able to partially overcome the inhibiting substances in the 
+20 gelatin. The growth in +40 and —25 gelatin fell far behind 
that in the other two. One was too acid and the other too alkaline.^ 
These tubes were kept in a cool box at temperatures varying from 10° 
to 22° C. (most of the time 13° to 18° C). In all the stab cultures the 
growth was best in the upper part, gradually fading out in the depths. 
The yellow color was also best developed near the surface, where there 
was freest contact with the air. There was no indication of yellow in 
the growth in the depths of the stabs. 

The following notes represent the usual behavior of stab cultures in 
15 per cent nutrient gelatin made neutral to phenolphthalein : 

Stock 244c (10 c. c. of very clear gelatin in tubes 16 mm. in diameter): Stab made 
Jmie2, from a fluid culture 11 days old (cauliflower broth); one needle-thrust the 
whole length of the gelatin (5 or 6 cm.); tube kept in the cool l)ox at temjwratures 
varying from 10° to 22° C. (most of the time 13° to 18° C). June 4 (range of tem- 
perature, 17° to 22° C): A whitish thread distinctly visible one-half way down; it 
fades out gradually. J une 5 (temperature, 13° to 15° C. ) : Stab whitish, feeble, visible 
three-fourths of the way down. June 8 (temperature, 13° to 16° C.) : Stab begins to 
fade out two-thirds down; growth decidedly better than in the -f-20 gelatin— at least 
twice as much growth; slight liquefaction — i. e., a pit at the mouth of the stab, 3 nun. 
wide and 2 nun. deep. June 10 (temperature, 10° to 13° C): Rather better growth 
than in the ^20 gelatin, but fading out in the depths; no marked increase of Hciue- 
faction; surface growth pale yellow, rather dry looking, al)out 3 nun. in diameter; 
surface irregular. June 13 (temperature, 12° to 16° C. ) : A better growth than in the 
-f 20 gelatin, but fading out in the depths; surface growth about 4 mm. in diameter, 
pale yellow; pit of iiquefac^tion 4 mm. wide and 2 mm. deep. June 18 (temperature, 
14° to 18° C. ) : Growth a little better than in the +20 gelatin, but not now strikingly 
so; the stal) fades out in the depths; surface growth pale yellow; pit of liquefaction 
only 5 or 6 nun. wide and 3 mm. deep; growth in the +40 gelatin is so slight as to 
be easily (overlooked; growth in the —25 gelatin is confined to the surface and there 
is no liquefaction. June 28 (temperature, 13° to 19° C): The pit of liquefaction is 
now 1 cm. deep and 1 cm. wide; it is a larger i)it than in the +20 gelatin, and there 
is more growth in it, and also more in the depths of the .^tab, but the latter fades out 
at the bottom; the surface growth is distinctly yellow; in the +40 gelatin there is 
a barely visible growth in the upper part of the stab, a pit of liquefaction 3 to 4 mm. 
wiile and 4 to 5 mm. di-ep, with a little whitish sediment at the bottom; in the —25 
gelatin there is no visi))ie stall, l)ut a distinctly yellow surface growth 5 nun. in 
diameter, and a feeble liquefaction under it. 

'Fuller: On the proper reaction of nutrient media for bacterial cultivation. Jour. 
Am. Public Health Association, Oct., 1895, p. 381. 

Tor the varying behavior of Ps. campestris in these four gelatins, see plate in 
The American Naturalist, March, 1899. 



24 

The PTOwth in the streak cultures was better than in the stabs. Even 
on the best gelatin and when large loops of fresh fluid cultures were 
used the streaks came up rather slowly, i. e. , in 3 to 5 days, at 18° to 
2-i° C. When 3 weeks old, these streaks were usually 2 to 3 mm. 
wide and 4 to .5 cm. long. The growth was pale yellow, not very 
dense, finely granular under Zeiss X 6 aplanat, and often fine crenulate- 
serrate along the margins. The streaks were made with a medium- 
sized oese (2 mm. diameter), and the germs did not show much tend- 
enc}^ to spread bej^ond the original streak. 

In streak cultures on stock 205 a much better growth was obtained 
than with concomitant cultures of Ps. campestris^ Ps. jjhaseoli, or 
Bacillm tracheij)hikis. In 14 days, at 22° to 24° C , the streaks were 
about 2 mm. by 5 cm. with fine crenulate-serrate margins; the surface 
was very pale yellow and finely granular under Zeiss aplanat. There 
was no liquefaction at this date, but ♦> weeks later all of the gelatin 
(10 c. c.) was fluid except a little in the bottom of the tubes and in the 
extreme top of the slant, and there was a moderate amount of pale 
yellow precipitate. During this period the tubes were in a cool box 
at approximatelv 20° to 24° C. 

Some interesting results were obtained with the malic acid gelatins. 
They did not inhibit growth, as fluids of the same grade of acidity 
w^ould ha^e done, and in the +36 gelatin growth Avas not retarded. 
In the +48 and +54 gelatin growth was slightly retarded at first, and 
in the depths of the latter it was never as vigorous as in the less acid 
media, the separate colonies in the lower parts of the stabs always 
remaining smaller. After a tuue, however, the growth in the upper 
part of the stab and on the surface of the +48 and +54 gelatin out- 
stripped that in the +36. On the fifth day there was most growth in 
the +36 gelatin and least in the +54. On the eighth day the retarding 
influence was still visible in the +54 gelatin. Subsequently it was 
overcome except in the depths. Two other interesting differences 
were observed. In 56 days, at 17° to 20° C, there was no liquefac- 
tion whatever in the +36 gelatin, and the color of the organism was a 
very pale yellow. In the -t-48 and +54 gelatins, on the contrary, the 
surface growth was bright j^ellow, and liquefaction set in at the end of 
the third week, involving the upper me-third of the 10 c. c. of gelatin 
in the course of the next 10 or 12 days. At the end of 66 days two- 
thirds to three-fourths of the gelatin in these tubes had liquefied. 

A repetition of the tests with the +36 gelatin gave no different results. 
In 40 days, at 8° to 20° C. (mostly under 15°), there was no liquefac- 
tion and no bright yellow color, although the stab was well developed 
and the surface growth was 7 by 8 mm. in breadth. Additional cul- 
tures in the +48 and +54 gelatin yielded no new or different results. 
After 40 days there was an abundant bright-yellow growth, and the 
upper one-third of the gelatin was liquefied to the walls. The remain- 



25 

der of the 10 c. c. of gelatin was unchanged, the stab fading- out in the 
depths to scattered round white colonies. 

It would seem, therefore, that excess of malic aid favored liquefac- 
tion and the production of the yellow pigment. PossiI)l\% however, 
these results are to l)e ascribed solely to changes in the physical char- 
acter of the gelatin. The melting point was slight!}' reduced by the 
addition of the acid and was lowest in the stocks which received 
the most acid. 

The most growth obtained on any gelatin was with +54 malic acid 
gelatin to which 10 per cent of cane sugar had been added. This was 
a slant culture kept in the ice chest at 10° to 25° C, for 6^ months, 
during all of which time it was overlooked, so that if there was any 
retardation of growth at iirst, there is no record of it. When exam- 
ined at the end of 6i months, there was a most copious growth, but no 
trace of liquefaction. At some time during the summer the ice was 
allowed to get low and the gelatin melted, allowing a copious bright 
yellow surface growth to fall to the bottom. Subsequent!}^, with the 
addition of more ice, the gelatin resolidified and a new surface growth 
formed. When examined at the end of the 6^ months, there was a 
dense bright yellow rim 12 to 15 mm. wide, and a copious surface 
growth separated from the yellow precipitate, already mentioned, by 
a mass of solid gelatin free from browning and clear, except for tiny 
scattered masses of bacteria imprisoned when the gelatin resolidified. 
The bright yellow surface slime was still alive. 

In the +4:8 gelatin with 5 per cent cane sugar, at the end of 40 days, 
at 8° to 20° C. (mostly under 15° C), there was a compact bright yel- 
low surface growth, 12 mm. in breadth and a distinct stab, but no 
liquefaction. This experiment was repeated at 12° to 20° C, using 
both +48 and +54 gelatin with 5 per cent cane sugar and continuing 
the experiment 30 days. During this time there was no liquefaction 
whatever in the +54 gelatin and only a very feeble liquefaction in the 
+48 gelatin, i. e., the distinctly yellow surface growth, 5 or 6 mm. in 
diameter, was sunken in slightly. In another experiment with +48 
and +54 gelatin with 10 per cent cane sugar, kept at 7° to 21° C. 
(most of the time above 14° and below 19°), there was no liquefaction 
in 49 days. 

The same results were obtained with gelatin (stock 244c), to which 
10 per cent cane sugar was added. After fJl days at 15° to 20° C. 
there was no liquefaction whatever in one tube and only the very 
slightest in the other, and no brown stain in either. The growth was 
better than in tubes of sugar-free gelatin which liquefied. 

There can be no doubt, therefore, that, while powerfully stimulating 
growth, cane sugar in small doses retards and in large doses entirely 
inhibits the liquefaction of the gelatin, whether the medium is acid or 
alkaline. 



26 

In all of the gelatins liquefaction took place very slowly. In the 
gelatins it seldom appeared earlier than the sixth day and often not 
until after the fourteenth day (temperatures 13° to 18° C., 18° to 21° C, 
and also 22° to 24° C), and nuich later on gelatins not so well adapted 
to its growth. Even when once initiated the peptonization of the gda- 
tins proceeded at such a snail's pace that 6 to 8 weeks usually elapsed 
before the whole 1(> c. c. became fluid. This ver}" slow liquefaction 
could not possibl}' have been due to the amount of gelatin used in my 
cultures, since this varied from 8 to 15 per cent, or to the fact that in 
preparing the media the gelatin was boiled only a verj^ short time so 
as not to injure its solidifying properties. Neither does the tempera- 
ture at which most of the experiments were made (8'-' to 21° C.) appear 
to haA^e been the retarding cause, since liquefaction was not more 
rapid at higher summer temperatures. To test this, a tube of stock 
2-14c was inoculated in June, 1897, and left for some weeks at room 
temperatures. These ranged from 25° to 34° C, the temperatures 
nearl}" all of the time being above 27° C, and often for many hours 
29° to 32° C, i. e., near the optimum for this organism. The folloAv 
ing notes on such a culture may not be without interest: 

Stock 244c. — Tube of 10 c. c. inoculated June 14, noon, with a large loop from a 
beef-brotli culture made June 3. Temperature, 25° C, gelatin fluid. 

June 15, 1 p. m. (temperature, 28° C. ). Feebly clouded throughout, no clouding 
down from the surface on shaking. Not so cloudy as concomitant cultures of Ps. 
pJiaseuU. 

June 16 (temperature, 29° C. ) : Much less cloudy than a corresponding tube of Ps. 
pliaseoli. Hundreds of tiny zooglcete have gathered into the top layers of the fluid 
gelatin and give to it, when shaken down, a granular appearance, 

June 17 (temperature, 28° C. ): Clear in comparison with a tube of Ps. phaseoH. 
Growth largely in shape of small zoogloeae, some of which are agaiii gathering into 
the top layers of the fluid gelatin. 

June 18 (temperature, 26° C. ): Very slowly increasing cloudiness with some tend- 
ency of zoogloete to gather into top layers of the fluid gelatin. 

June 19, temperature 26° to 27° C. ; June 20, temperature 29° C. 

June 21 (temperature, 27° C): A pale yellow rim on the tube at the surface of the 
gelatin. No pellicle, but some gathering of zoogloepe and individual rods into the 
upper layers. Not mucli precipitate. On gentle shaking the fluid clouds down 
from the surface. 

June 28 (temperature since last record, 25° to .31° C. ): A moderate amount of 
yellow precipitate, much more than on the 21st. A copious yellow rim on the tube 
at the surface of the gelatin. Gelatin nearly clear until gently shaken, when it 
clouds down from the aggregation of germs in the surface layers. Numerous small 
zooglcese still visible. On putting into ice water the gelatin soon became solid. 

July 8 (temperature since last record, 29° to 33° C. ; i. e., very hot summer weather) : 
Body of the gelatin nearly clear. A decided rim of yellow on the walls of the tube 
at the surface and some clouding of the upper layers of the gelatin. Considerable 
yellow precipitate. The fluid clouds down on shaking. It still solidifies quickly in 
ice water. 

July 29 (temperature since last record, 26° to 34° C. ): The gelatin has become 
clear. There is a yellow rim on the walls of the tube above the surface of the fluid 
and a copious yellow precipitate. The gelatin still solidities in ice water, but it is only 



27 

semi-solid at 15° C, and is perfectly fluid at 18° C; i. e., the meltin-ic point has l)een 
rednced (> to S deirrees, indicating a partial peptonization. 

The most rapid liquefaction obtained was witli a .streak culture on 
stock 205. It was inoculated with a large loop from a fluid culture 
10 days old and was kept at 18^ to 24^ C. On the twelfth day there 
was a thin, pale-yellow streak 2 to 3 mm. wide and 5 cm. long, in the 
middle part of which there was a small hole containing fluid g-elatin. 
This liquefaction began the ninth or tenth day with a slight sinking 
in of this part of the streak. On the twentieth day the liquefaction 
involved about one-fourth of the gelatin (10 c. c). On the twenty- 
ninth da}' fully three-fourths of the gelatin was fluid and there was a 
copious pale-yellow precipitate (temperature since last record, about 
22° C). Not until the thirty-ninth day was all of the gelatin fluid. 

All of these gelatins contained some muscle sugar, which may have 

slightly retarded liquefaction, since various writers have shown for a 

numlier of bacteria that small doses of grape sugar retard and large 

ones prevent liquefaction. 

2N 
In stock 208 (stock 205 + enough -j- c. p. HCl to make it neutral 

to sensitive neutral litnuis paper) there was no growth whatever at 
10° C. This inoculation was a streak the whole length of a long slant. 
It was made with a large loop of fluid from a beef -broth culture 7 
days old and well stocked with living germs, as shown by the result of 
concomitant inoculations into other media. This culture was kept 
under ol)servation 22 days. Inasnuich as the organism grew well in 
stock 205, and will also grow at 10° C, the failure of this tulje was 
ascribed to the sodium chloride developed in the gelatin by the addi- 
tion of the HCl, enough being produced to give a feeble taste of salt. 
(See p. 13.) 

In the + 20 gelatin (stock 244b) this organism and Fs. phaseoU 
behaved nuich alike, both growing very much better than Pd. 
campestris. 

In poured plates (+ 20 gelatin in Petri dishes) the buried colonies 
were round, roundish, or ellipsoidal, with smooth margins. No spin- 
dle-shaped colonies were seen and none or few having rough, irregu- 
liir margins. (See plate cultures under Nutrient Agars.) 

The si/e of these buried colonies in densely crowded ])lates (2,00() to 
3,000 colonies per held of Zeiss 16 nun. aprochromatic and 12 com- 
pensating ocular), after 5 days at 13° to 16° C, was usually 16 by 16/^ 
or 16 by 20//. Some, however, were smaller, and others were as large 
as 24 by 24/< or even 28 l)y 32/^. The colonies were nearly colorless 
and very finely granular, with margins sharply defined and free from 
irregular outgrowths. Occasionally there were queer looking com- 
pound colonies i-t^sulting apparently f rf)m the growth of tlu^ coiuponent 
meml)ers of small /.oogloiac. The jilates were distinctly clouded to the 



28 

naked eye, but there was no liquefaction. Ten da3^s later the colonies 
were decidedl}^ larger, l)ut otherwise much the same. The margins 
were still well defined and regular and there was no liquefaction. In 
less crowded plates of the same gelatin (ii(»0 to 600 colonies per field) 
at the end of 5 daj^s (13° to 16° C.) the buried colonies were like those 
just described, only larger — 28 by 28yM to 56 by 61yU, the greater num- 
ber being 32 by 32/^ to 36 by 36yM. Ten days later, at 12° to 16° C, 
the colonies had doubled in size, were round, roundish, or broadly 
elliptical, pale and fineh^ granular (16 mm., 12 oc), with clear, well- 
defined margins. The colonies in the deeper layers of the gelatin were 
decidedl}^ smaller than those near the surface. The largest of the 
buried colonies, including some of the clumpy compoimd ones, were 
then a feeble tint of yellow. This color was onl}' visible in the upper 
colonies. No spindle-shaped colonies were visible. Only two small 
pits of liquefaction were observed. These arose from surface colonies, 
of which very few were visible; i. e., the buried colonies did not easily 
break through and come to the surface, and free access of air appeared 
to be necessar}^ for liquefaction. 

None of the man}- pure cultures of Ps. Jiyacinthi in gelatin developed 
any gas bubbles (see Fermentation tubes), and the gas bubbles observed 
b}^ Dr. Wakker in his gelatin cultures must be attributed to some 
contaminating organism.^ Contrary, also, to Dr. Wakker's statements 
the gelatin did not become brown. In all of the gelatin cultures 
(tubes under observation from 3 to 6 weeks or more) it remained free 
from browning; i. e., was of the same color as when inoculated. 

Ps. co/mpestris and Ps. phaseoli both liquefy gelatin, and more readily 
than Ps. hyacinthi., but none of them are rapid liquefiers. 

In nutrient gelatin stock 178, consisting of 1,000 c. c. stock 473b 
(beef broth acidity +17) and 100 grams of gelatin with 17 c. c. of 

^ NaOH, Ps. stewartt, made a good growth. At the end of the fort}"- 

first day (temperature 17° to 22° C.) there was along the track of the 
needle puncture a thin line of growth, increasing towai'd the surface, 
and a dense, rather dry, and slightly roughened bright buff-yellow 
surface growth 7 mm. in diameter, but no liquefaction. 

^ The only gas that ever appeared in any of my cultures was in one of four gelatin 
tubes made June 23, 1897, in Dr. Wakker's manner, i. e., directly from the yellow 
interior of a disorganized bundle in an otherwise sound bulb scale. This tube was 
inoculated with great care to avoid external contaminations, and it appeared to be 
all right for some time, but after 22 days a gas bubble appeared in the gelatin near 
the bottom of the stab (temperature 12° to 18° C. ). This was then the only evidence 
of anything wrong, but two weeks later the nature of the contamination became 
perfectly plain, the gelatin becoming fluid to the walls of the tube in the upper 
two-thirds, the upper part of the liquefied i^ortion Ijeing greenish fluorescent and 
the bottom covered with a copious whitish precipitate with a little of the yellow 
Ps. kyacinthi mixed in. Undoubtedly this was an aerial contamination, as Ps. hyacinthi 
is never greenish fluorescent. 



29 

The following may be noted as some of the most characteristic pecu- 
liarities of Px. kyac'mtkl on gelatin culture media: 

(1) Liquefaction in neutral, acid, or alkaline gelatins, made with pep- 
tone and beef broth containing muscle sugar, proceeds very slowly at 
all temperatures (8*^ to 32° C), reaching out to the walls of the tube 
long before it has involved the whole of the gelatin in stab cultures. 

(2) The addition of 5 or 10 per cent of cane sugar greatl}^ favors the 
long-continued growth of the parasite and does not interfere with the 
development of the yellow pigment, but entirel}^ prevents liquefaction, 
or reduces it to an insignificant phenomenon easily overlooked. 

(3) An extremely superficial, whitish, chemical film appeared after 
some weeks around the surface growth, even when cane sugar was 
added (see Nutrient Agars). 

(4) None of the gelatins showed any brownmg or other stain of 
the substratum. 

(5) No gas bubbles appeared, except in one tube which turned out 
to be contaminated, 

(6) Quite unlike strong growing facultative anaerobic species, such 
as Bacillus coll or B. cloaccB^ the stabs always faded out gradually in 
the depths, being best developed near the surface, and least in the 
deeper parts of the gelatin. 

(7) The separate colonies, which in many instances formed the 
lower part of the stab, were always round or roundish, never spindle- 
shaped, and were never distinctly 3'ellow, i. e., the}^ were white or 
whitish, the free access of air appearing to be requisite for the devel- 
opment of the bright 3'cllow pigment. 

(8) Even in Petri dish cultures the surface colonies developed better 
than the buried ones, and the buried colonies in the surface layers 
grew better than those in the deeper parts of the gelatin. 

(9) Peptonized beef broth gelatin which is only neutral or feebly 
alkaline to litnms exerts a retarding influence on growth. The reac- 
tion for best growth of this species lies somewhere between +15 and 
of Fuller's scale. Litmus neutral gelatin also exerts a retarding 
influence on several other plant parasites, e. g., Pseudomonas cwm^es- 
triH and Bacdhim amylovorus. 

NUTKIENT ACiAKS. 

(1) Streaks of Ps. %(7(?/w/A/ on brown agar No. 207 (-f 22) yielded a 
good pale yiOlow growth and the same sort of crystals as cultures of 
/^•. ca/nj)r.sfrl.s^ viz, large compound X -shaped crystals of magnesium 
ammonium phosphate.' These crystals were, however, less abundant 
than in cultures of Z^-. cavijicHtris of the same age, and this was attrib- 
uted to a feel)ler production of ammonia. The streak was still pale yel- 

'The composition of this agar is givt'ii in Cmtralbkitt fur Baklerlologie, 2 Abt., Bd. 
Ill, p. 480. 



30 

low at the end of a month (livi ng-rooni temperatures of March and April) 
and not at all sticky or gelatinous; Growth on this agar was retarded 
a little at first, but b}^ the fifth day, when inoculated with large loops 
from })eef -broth cultures a week old and kept at 21"^ to 23"^ C, there 
was a good, dense, yellow streak. 

Fifteen months afterwards, a carefully preserved flask containing 500 
c. c. of this same agar was opened and 100 c. c. of distilled water added 
to make up for what had slowl}' evaporated. The agar was then 
steamed, filtered, and filled into clean test tubes, forming stock 307. It 
was slightly browner and less elastic (more brittle) than when first made. 
Duplicate streak and stab cultures of this organism and also of Ps. cam- 
pedris and Px. phnseoli^ both of which formerly grew well upon this 
agar, were made, using large loops of fluid cultures twelve dajys old. 
The loops were drawn lengthwise of the central part of the slant and 
were easily visible after the removal of the oese. Ps. j^^Mseoli re- 
fused to grow on this agar, either in streaks or stabs (4 tubes, 56 
days). Pa. caiapeatris refused to grow in streak cultures and there 
was no \'isible growth in the stab cultures until after the sixth day 
(temperature 20° to 25°). This agar also exerted a powerful, restrain- 
ing influence on Ps. hyacinthi. To the twelfth day the streak cultures 
showed no growth (temperature 20° to 25° C). On the nineteenth day 
one of the streak cultures showed a distinct growth, but it was only 
1 or 2 nmi. by 10 nmi. and was mostl}' in the agar. On the twenty- 
sixth day the streak measured only 25 mm. I^y 3 to 5 mm. The streak 
was dense, 3'ellow, smooth, and wet-shining. The margins were thin 
and well defined. The organisms had grown down into the agar. On 
the fift3'-sixth day the streak was 42 mm. by 5 to 8 nmi. It was yel- 
low, smooth, wet-shining, and contained several of the large X shaped 
cr3^stals. No growth ever appeared in the other streak cultui-e. 
Growth in the stab cultures was also much retarded and was verv slow 
to appear upon the surface. This agar was not retitrated, to deter- 
mine its acidity, but it was acid to neutral litmus paper, or, at least, not 
alkaline. When the moistened paper was dry, it seemed to be neutral. 

(2) The following agar made by Mr. P. H. Dorsett was also tried: 

1,000 c. c. of distilled water. 

10 grams of Witte's peptonuiu t^iccum. 

10 grams of agar. 

2.5 grams of Liehig's extract of meat. 

This fluid was cleared b}^ the addition of the whites of 2 or 3 eggs 
and rendered moderately alkaline to litnuis by the addition of carbon- 
ate of soda. It contained no muscle sugar and was +15.5 of Fuller's 
scale. 

Repeated tests were made on this agar, usually in the form of streak 
cultures. There was no I'etardation of growth. The streak was dis- 
tinct in 22 hours, at 27°, when the inoculation was made from a coconut 



31 

culture 8 days old, and in 28 hours, at 22° to 28°, when the inocula- 
tion was made from an agar culture 13 daj's old. This orowth was 
thin, distinctly yellow, smooth, wet-shining, translucent, homogeneous- 
lookino-, and not scanty. There were no down-groAvths into the agar, 
and the margins, while thin, were well defined, i. e., not nebulous. 
Even on recent!}' slanted agar the organism showed little tendency to 
spread widely. The streaks remained translucent for a long time, a 
penhokler being easily visil)le through them after a month or more. 
No crystals were formed and there Avas no ])rowning of the agar even 
in old cultures. (An undescribed, white, endosporc-bearing Schizo- 
mycete, isolated from rotting tomato fruits, lirowned this agar readil3\) 

After a month or two the streaks began to dry out, ])ut the surface 
remained smooth, even in old cultures, and was homogeneous looking, 
except that, after some weeks, colonies of the same species frequently 
formed on the surface of the yellow slime. Tested on the seventeenth, 
forty-seventh, and fifty-third days, with neutral litmus paper, the 
slime was feebh^ to plainly alkaline. On the sixty-sixth day it was 
stronglv alkaline. No acid reaction was ever observed. 

An extremely thin, whitish, chemical deposit appeared on the surface 
of the agar beyond the streak, after a week or two, and slowly in- 
creased, l)eing best developed on the lower part of the slant where the 
growth was best. This film dissoh^ed in h) per cent acetic-acid water 
in about one minute. 

On the fort3^-seventh day the slime consisted of short slender rods, 
single or in pairs. Four rods joined end to end were rare, and chains 
were A'er}' rare. After a long search oidy one chain was found (about 
10 segments). In none oi these tubes did the growth increase much 
after the second week, and it never became what might be called 
copious. No reticulate or shagreen surface ever appeared in any of 
these cultures. (See Sugar agars under Relative initrient value of 
carbon compounds.) 

Streak cultures of T*s. eampesiris, Pi<. phaseoll., and occasionally of 
Ps. stetvarti^ were made for comparison. The Ijehavior of these three 
parasites on this agar was nmch the same as that of P.s. Ityacintlu. All 
grew without retardation, and after a few days there was about the 
same amount of smooth, translucent yellow slime. No crystals were 
formed in the agar and no ])rown stain appeared, even in old cultures. 
The whitish chemical film appeared around the streaks whichever 
organism was used, and in some cases it was noted that it was best 
developed in the lower part of the streak. In case of 7\-. camjyentris^ 
this film was examined microscopicalh' and found to consist of very 
minute granular bodies, which were readily soluble in 10 per cent 
acetic-acid water, but did not show any decided crystalline structure 
when examined with the polariscope. 

In one series of tubes, after five days on this medium, Pa. hyaclnthi^ 



32 

Ps. camj)estrls, and Ps. phaseoli looked much alike, Init the hyacinth 
germ was the brightest ^^ellow and the cabbage germ the palest. On 
the seventeenth day Ps. liyacinthl was also noted as brighter yellow 
than the others. In another series of cultures the slime of Pa. liyacin- 
thl was distinctl}' 3'ellower on the sixteenth day than that of Pa. cam- 
pestris, Ps. jylimeoli., or Pa. stetvarti. On the fortj^-seventh day the 
color of Ps. hyacinthi was saflfron yellow (Kidgway, VI— 1). The color 
of each of the other three organisms was paler, lying between buflf 
j^ellow and chrome yellow. The cultures of these three organisms 
were also alkaline to litmus on various dates, and in cultures of the 
same age the slime on the seventeenth and forty-seventh da}^ was more 
stronglv alkaline than that of Pa. hyacinthi. All said, however, the 
cultures of all four of these organisms were much alike on this 
substratum at all stages of growth. 

(3) Poured plates of Ps. hyacinthi were made in Petri dishes, using 
one of Mr. M. B. Waite's standard (litmus) neutral agars,*in which 
Bacillus amylovorus had been found to make a good growth. In very 
crowded plates containing 8,000 to 10,000 colonies per field (Zeiss 16 
mm. and 1:2 ocular), the agar, at room temperatures (25" C), became 
milk}^ cloud}' on the fourth day. There were no distinct surface colo- 
nies, and the buried ones were irregular in outline, i. e., with ragged 
margins like the colonies of Ps. cainpestris. In a plate of the same 
age, but containing only about 600 buried colonies in each field (16 
mm. 12 ocular), the colonies were larger, but otherwise of much the 
same character, i. e., roundish or somewhat irregular in shape with 
rough margins. No distinctly fusiform colonies were to be seen. 
Fusiform buried colonies were, however, observed in plate cultures 
made from Mr. Dorsett's agar. 

In thin sowings of Ps. j^haseoli on nutrient agar in Petri dishes 
(25 surface colonies and about 40 buried ones), on the seventh day 
(25° C), the surface colonies were pale yellow, smooth, wet-shining, 
not piled up, and had thin, distinct margins. The}^ were 1.5 to 4 
mm. in diameter. The buried colonies were elliptical or bluntlj^ 
pointed (0.6 to 0.7 by 0.3 to 0.4 mm.). The margin of the buried 
colonies was distinct but frequently a little roughened under the 
Zeiss aplanat. On the eleventh da}" some of the buried colonies 
were breaking through to the surface. The entirely buried ones 
were still small and elliptical, with either pointed or rounded ends 
The}' were yellow in color and their margins were more or less rough- 
ened by small blunt projections. The surface colonies were now 3 to 
8 mm. in diameter, smooth and wet-shining. Buried in the colony 
were a number of lighter and darker rings. The color was distinctly 
yellow, but pale rather than bright, i. e., somewhat like straw yellow. 
The margins were thin and well defined. Under high magnifications 
zoogloefe were visible in the colonies. There was nothing peculiar in 



33 

the margiiuii growth and the individual rods on the margin were not 
ver}' distinct (Zeiss 16 mm. and 8 mm. apochromatics with compensat- 
ing oculars up to No. 18). 

Potato. 

More than 100 cultures of 7^s-. hy<(ct)ithl have been made on potato. 
This medium was usually prepared by steaming slant cylinders (5 to 6 
cm. long b}' 1 to 1.3 cm. thick) in well plugged clean test tubes of 
resistant glass, in 1 to 3 c. c. of distilled water. Occasionally I made 
use of drier cylinders, onl}" the curved bottom of the test tu])e 
being tilled with water. The potatoes found in the Washington 
markets usually bear three steamings of 15 or 20 minutes each without 
cracking open or losing their smooth surface and white color, and, if 
they are prepared beforehand in a cleanly way, this short cooking on 
3 consecutive da3^s is suihcient to render them sterile. 

The color of the organism on this substratum varies from bright 
yellow to pale or dirty j^ellow. Usuall}^ the color is distinctly l)righter 
than in corresponding cultures of Ps. campestris or Ps. 2)h(f'S&oli. 
During the first week or two in most cases the color may be said to 
approximate Ridgway's Indian yellow (VI-5); i. e. , it is nearly as l)right 
as gamboge. As the culture becomes old the color dulls. In well- 
grown cultures not too old the color approximated Ridgway's wax 
3'ellow (VI-7). The color of the slime from a typical potato culture 
30 days old was exactly Ridgway's gallstone yellow. Frequentl}' the 
germs from very old cultures were brownish yellow in mass. The 
slime from a culture -18 days old was between ocher yellow and tawny 
olive. 

Usually, at temperatures of 20° to 25° C, in inoculations made from 
broth cultures, the bacterial mass was not plainly visible along the 
streak until after 2 or 3 days. In one case it was distinctly visible in 
24 hours, but then the temperature was 28° C, and the inoculation 
was with a mass of yellow slime from the surface of a potato culture. 
After a week or two the germ appeared in potato cultures as a thin, 
rather feeble, wet-shining, pale yellow or bright yellow growth, 
covering a part only or nearly the whole of the exposed potato, but 
showing no inclination to fill up the water. 

There is, of course, a moderate clouding of the fluid aroimd the 
cylinder, and after some days or weeks there is a scanty yellow pre- 
cipitate which does not increase (14, 24, 41 davs). All distinctly 
\'ellow growth is restricted to that part of the cyliMder above the 
water. This growth is so thin that very often the slight irregularities 
of the surface of the sul)stratum are not obscured and. as the lluid evap- 
orates, the bacterial layer shows no tendency to follow down flic sides 
of the cylinder and occupy the exposed surface of the potato. There 
is never any lilling up of the fluid with yellow slime, such as always 

21788— No. 28—01 3 



34 

appears in potato cultures of /i'. camjjestrls and Ps. j>haseoU. In 
comparison with eitlier of these species the growth of 7*y. hyacinth I on 
potato lao-s far behind, e. o-., at the end of 2 days at 20° to 25° C. it is 
not one-twentieth as much, and at the end of 2 weeks it is not one one- 
hundredth as much. After the second week the h3'acinth germ shows 
very little increase t)f growth on potato, whereas the other two germs 
continue to multiply for many days, converting the fluid in the bottom 
of the tubes into a solid mass of yellow slime even when as much as 2 
or 3 c. c. of water is present (see Tafel VI, fig. 4, Central!), f. Bakt., 2 
Abt., Bd. III). This feeble growth on potato serves as a ready means 
of distinguishing this organism from the cabbage germ and the bean 
parasite, but not from some other yellow bacteria, e. g.. Pa. stewarti. 
The surface of this 3'ellow growth, in Pa. hyadnthl even after several 
weeks, is usually homogeneous, smooth, and wet-shining. Ver}^ rarely, 
after the third week, I have seen a shagreen surface on the extreme 
upper part of the potato cylinder. After a few weeks (3 to 4) the 
bacterial layer is slightly sticky, often stringing up 1 to 2 centimeters 
when touched with the loop. After 3 or 4 weeks, when a considerable 
portion of the bacterial layer may ])e presumed to be dead, pale j'ellow, 
smooth, shining colonies, 1 to 3 mm. in diameter and gradually rounded 
up from the margin to a rather thick center, are sometimes seen dot- 
ting the surface. Zoogloete occur in this slime, at least after some 
weeks (30, 37 days), even when they are not visible in the form of 
shagreen. In one culture which was examined microscopically in 
water on the thirtieth day they consisted of numerous tiny ragged 
aggregates of 10 to lOO or more individual rods. 

All the cooked potatoes I have ever tested have been feebly acid to 
litmus. This acidity is overcome by the growth of Ps. JiyactntJi!, the 
fluid first changing to feebly alkaline, and then becoming and remain- 
ing strongly alkaline (13, 22, 24, 30, 37, 56, 67 days). 

The substratum out of the water is changed (as happens in case of 
many other bacteria) to a pale gray within a few days, and this color 
extends downward slowl}^ into that part under the water, until after 
3 or 4 weeks all is grayed; usually by the eighth or ninth day the 
gray color extended down under the water 1 centimeter. This color 
is a pale smoke gray, lighter than Ridgway's smoke gray (1-12). 
Its depth of color varies in dift'erent cultures, depending apparently 
on slight chemical difl'erences in the potatoes used. The fluid in the 
bottom of these tubes remained free from color for a time, but after 
3 or 4 weeks it became feebly browned. This brown color was distinct 
enough to be detected without check tubes, but it was never more 
than a weak stain (67 days). 

The cylinders were firm and resistant between the fingers, even after 
the hj^acinth organism had grown on them for 6 or S weeks, and their 
cellulose was certainly not acted upon to any marked degree. The 



35 

starch was also but little affected (see Feel)le diastasic action). In 
3^oung- cultures there was no smell; in old cultures there was a feeble 
odor. 

Ps. stevxirtl behaves on potato much like Fs. hyacintld. 

Potato c^dinders on which Ps. caiiipeHtrls and Ps. phaseoli have 
grown are somewhat softened as if the middle lamella of the cell wall 
were attacked. 

Coconut. 

This substratum was made by putting clean, washed slices of coco- 
nut flesh into sterile, cotton-plugged test tubes, adding 1 or 2 c. c. of 
distilled water (from a tin-lined copper tank), so as to cover the lower 
one-third or one-half of the slice, and steaming 15 or 20 minutes on 3 
consecutive days. The coconut flesh contains no starch and very 
little grai^e sugar (reducing substance), but is rich in oil. With the 
exception of rice it is the whitest culture medium known to the writer. 
All the yellow germs which I have tried make a satisfactory growth on 
this medium, and owing to its whiteness the contrast in color is very 
striking. 

Ps. kyacinthi grows on this substratum without retardation. Cul- 
tures at room temperatures of 20° to 25° C. usually appeared in 36 to 
48 hours, Avhen not too sparingly inoculated, and made a good growth 
in 3 or 4 days. Growth continues for several weeks and usually 
becomes quite abundant (in one culture on the fiftieth day the bright 
yellow slime was over 1 mm. deep), but the organism shows no tend- 
ency to thicken the fluid or make it yellow, or to cover the submerged 
parts, any more than on potato, and there is little precipitate. The 
growth on this medium is smooth, wet-shining, and homogeneous. It 
is not sticky except in old cultures, which sometimes string up slightly. 
After 50 days in the ice chest the bacterial layer was not noticealdy 
sticky, but it dissolved slowly in water and then lifted up 1 cm. when 
touched with the loop. 

The color of Ps. Kyacinthi on coconut is bright yellow. After 7 
da3's' growth on coconut the organism was yellower than an equally 
good growth of the same age on turnip. At the end of the same 
period it was decidedly yellower than a corresponding culture of Ps. 
campestrls. After 7 days and 25 days its color was about the same as 
that of a corresponding tube of Ps. phaseoli. After 49 days the color 
differed, if at all, from the color of a corresponding tube of Ps. phaseoU 
in being a trifle brighter, i. e., in containing less orange. 

After 50 days at I'oom temperatures of 18° to 27° C. its color was 
between Ridgway's lemon yellow and his gaml)oge yellow (VI-10 and 
11). After the same period in the ice chest, at 7° to 15° C, its color 
was between canary yellow (light cadmium) and chronie yellow (Kidg- 
way, VI-8). 



36 

No spores could he found in ji culture which had grown in the ice 
chest for 50 days. 

A culture at room temperatures w^as feebly alkaline to neutral litmus 
after 50 da^-s. A culture which had been kept in the ice chest for the 
same lenotli of time, and consecuiently was not so far advanced in 
growth, was distinctly alkaline, i. c., more so than the preceding. 
After Si days in the ice chest a culture was strongly alkaline to neutral 
litmus. 

No acid reaction was observed. 

No brown pigment was developed. After -19 days at room temper- 
atures the substratimi was as white as when inoculated. 

No cy^tohydrol3'tic action was observed. After the organism had 
grown on it for 81 days (ice chest) the substratum was as tough as 
when iirst inoculated. 

No cr3^stals were observed and there was no decided smell. 

Ps. .sfewartl grew in nmch the same waj^ on this substratum, but 
frequenth" made less growth. The color of its slime was buff j^ellow, 
and cr3\stals were formed. 

Radish. 

Slices of small, tender, red-skinned, turnip-rooted radishes were pre- 
pared in the same way as the potato. 

On this substratmn the hyacinth organi^^m made a good growth, as 
the followino- record shows: 

Stock 211. — ]Mufh water. Inoculated February 19, 5 ]>. iii., from a lu'cf-broth cul- 
ture 14 days old, and kept at room temperatures. 

February 22, 3 p. in. A good growth on the surface above the water, pale yellow, 
wet-shining. Fluid clouded, no precipitate. 

February 26. A wet-shining, pale yellow growth over the whole exposed surface. 
A good grf)wth, Init not more copious than that in a corresponding tube of Ps. cam- 
pestris. A moderate amount of precipitate. This is a yellower germ than J's. nnn- 
pestris. It shows so, plainly, on all four media (radish, turni}), carrot, and coconut). 

March 5. A copious growth. No l)rown pigment. 

March 16. No brown stain. 

April 9. The culture has begun to dry out, Init there is still about one-half c. c. of 
fluid in the bottom of the tube. There is a thin pale-yellow precipitate. The sub- 
stratum has changed color decidedly. The check tubes are still white, l)ut the sub- 
stratum in this one is of a color not easily described, i. e., unlike any in Ridgway's 
color system. It approaches his raw Sienna ( V-2) , and if that color had in it a very 
slight amount of brown it would closely resemble the color of this substratum. On 
long standing, therefore, a brownish pigment appears in tubes of radish. 

A year later this experiment was repeated, using globose red and 
oblong white radishes. The results were substantiallv the same. 
There was a copious, very wet-shining, very pale-yellow growth, which 
never became ])right yellow like that on coconut. In each case the 
substratum tinally became brown, but this change took place very 
slowly, and the color never became deeper than a pale russet (64 days). 



37 

The slinio was feebly alkaline on tlie thirty-fourth and sixty- fourth 
daj^s whit'hi^'ei- niodiuni was used. 

AVjiite Turnip. 

Slices from the roots of smooth, green-leaved (nong'laucous), flat- 
bottomed, edible, white turnips were prepared in the same way as the 
potato cylinders. 

The hyacinth organism grew well on this substratum and without any 
marked retardation. On the third day, at 21'^ to 23'^ C. , the growth was 
very feeble in comparison with that of Ps. cmrq^estris or Ps. plumeoli. 
On the seventh day, at 20*^ to 23°, the growth was copious over the whole 
of the exposed part of the cylinder and the fluid was ver}' cloudy, but 
there w^as little or no precipitate. On the twenty-second day growth 
was copious in the air and also in the upper part of the water, i. e., 
there was a better growth than in corresponding tubes of potato. 
After 54: days there was still a copious growth. 

The surface of the slime was smooth and wet-shining, even in old 
cidtures (54 da3\s). 

After 7 da3's at room temperatures the color in one tube was pale 
3^ellow, except the scanty precipitate, which was canary yellow. After 
22 daj^s the same culture was pale 3'ellow. In another tube, on the 
seventh da}', the color was unlike any in Ridgwav's book, but approxi- 
mated his Naples yellow (VI-IS). This slime was plainly yellower 
than the equall}' copious growth in a corresponding tube of P><. caiii- 
■peKtriK. At the end of 25 days the slime in the upper part of the tube 
against the glass had developed a pale reddish-yellow color, quite in 
contrast with the color of a corresponding tube of Px. p^iaseoll. There 
was also the merest trace of this color in the first cultures on radish. 
After 50 da3's at room temperatures the slime in one tube was "dirt}'^ 
yellow," while in another it was "pale 3'ellow," i. e., much paler than 
in a culture of the same age on coconut. In mass, on white paper, 
this pale yellow slime was between Ridgwa3''s ])uff 3^ellow and maize 
yellow (VI-19 and 21). 

After 54 da3'^s, at room temperatures, the slime snowed no alkaline 
reaction, but was plainly acid to neutral litnuis paper (only one tube 
tested). This red r(MU'tion was appar(;nt at once and l)ecamft stronger 
as the paper dried. 

A brown stain slowly developed in the substratum, ))eing clearly 
visi))lc onl3' after 2 or 3 weeks. On the twent3"-second day and the 
thirt3'-eighth da3' the substratum was not browned as much as in corre- 
sponding cultures on 3'ellow turnips. On the thirty-eighth da}' the color 
in one tu))e approximated Ridgwa3''s russet. In another culture of 
the same age the ))rown was paler, approximating his tawny olive. 
On the foi-ty-ninth da3' the substratum was darker than on the nine- 
teenth, and was several shades daiker than in a corresponding tube of 



38 

radish. At this time the color was approximately burnt umber (R. 
1II-8), but it was a trifle lighter than that color and appeared to have 
a trace of red in it. 

The stain in old cultures was always a distinct but feeble brown 
and differed from the stain of P><. campestris principally in being a 
shade or two lighter. 

Yellow Turnip. 

This medium was made in the same way as the preceding. The 
turnips were of the same habit of growth as the white ones but were 
sweeter to the taste and were distinctly yellow. The relative amount 
of sugar in the two kinds was not determined. 

Ps. hyacinthi grew remarkably well on this substratum and without 
any marked retardation. At room temperatures of IS"' to 25^ C. the 
bacterial layer was usually visible on the third day. A week after 
inoculation growth in the air was "copious" to "very copious," and 
growth in the water had been sufficient to produce a sirup}^ liquid. 
This growth continued for several weeks, entirely hiding the aerial 
part of the cylinder and converting all of the fluid (1 to 2 c. c.) into a 
solid slime which would not flow. In one tube, at the end of 8 days, 
there was 100 times as much growth as in corresponding cultures on 
potato. In other words, the organism behaved on this substratum 
exactly after the manner of Ps. canqMstris and Ps. 2yhmeoU on potato. 

At room temperatures the growth was smooth, wet-shining, and 
homogeneous-looking from the start, and it remained so for 2 months. 
There was never any shagreen surface or other surface indication of 
zoogloeifi; nor was the dense copious slime stick}^ (eighth day). 

The color of the slime was pale yellow; i. e., distincth^ paler than 
on some other media. Examinations of 4 difi'erent cultures on the 
third, fifth, seventh, eighth, twelfth, twentieth, twenty-second, and 
thirty -second days all agree in this particular. On the fifth day the 
slime was a little brighter than Naples yellow. On the eighth day the 
color of the slime from another tube closely resembled Naples vellow, 
but was lighter j^ellow than the slime from a corresponding culture on 
carrot. In one instance the precipitate was canary yellow, while the 
aerial slime was paler yellow. On the fifty-fourth day, viewed without 
removal from the tube, the slime appeared to be russet color, but on 
putting a mass of it on white paper and comparing with Ridgway's 
plates its color was ochraceous. 

On the eighth day the slime was distinctly alkaline to neutral litmus 
paper (one tube only was tested). In another tube, on the fiftj^-sixth 
day, the slime was feebly alkaline. 

No stain of the fluid or of the substratum was visible during the first 
week of growth, but during the second or third week a brown color 
appeared and slowly increased in depth. On the twentj^-second day 



39 

this color rcsoiiihlod tawin' olive, but was paler. On the thirty-second 
da}' it was still only a pale brown. After 69 days the color of this 
pigment was between Ridgwa3^'s russet and burnt umber. 

Bdc/Uux <(i)iylovo7'us made only a moderate g-rowth on this substratum, 
and produced no brown stain, but developed an acid. 

After a 3'ear or two this test of Ps. hy acini hi was repeated at 20° to 
25*^ C, using yellow globe turnips (a rough-leaved, nonglaucous sort). 
On the third day 5 sq. cm. of the slant surface was covered with a 
smooth, wet-shining slime, which was abundant enough to hide the 
sul)stratum. On the seventh day there was a copious yellow, smooth, 
wet-shining growth over the whole cylinder and in the water, but no 
browning- of the substratum. On the eighteenth day the fluid was so 
full of the yellow slime that it would not flow when turned bottom up, 
and there was a slight browning of the upper part of the substratum. 
On the twent}' -seventh day there was a distinct pale-brown stain in the 
upper part of the substratum. On the thirty-fourth day the slime 
was neutral to neutral litmus paper. On the fiftieth day the color was 
between 1)urnt imi})er and mummy brown, and the fluid was grown solid 
with the yelloM^-brown bacteria. On the sixty-fourth day the color of 
the substratum was burnt umber. The culture had a faint, peculiar 
smell. The outline of the substratum was preserved, but on being 
removed from the tube it was mushy soft to the fingers, and even to a 
piece of litmus paper which could be thrust into it. The substance 
was feebly alkalin(\ throughout. There were some involution forms, 
but nothing resembling spores. Large crystals were present. 

No starch remained, if any was originally present. The middle 
lamella was dissolved or greatly softened. The cell wall proper (of 
the turnip) was apparently intact, but for the most part the contents 
of the cells were gone, although some large and small rings of dou))tful 
origin remained. With Russow's cellulose test many of these cells of 
the substratum did not stain at all, a few became deep blue, and a few 
deep purple. In most, the walls remained colorless, but the contents 
of the cells reacted pale blue. Corresponding results were obtained 
with chlor-iodide of zinc. The contents of the cells frequently became 
blue while the walls remained colorless or turned to brown or reddish 
brown. Doubt was thrown on these results, however, by the behavior 
of the check tul)es, which also gave an uncertain cellulose reaction 
with these reagents; i. e., cell walls purplish in the chlor-iodidc of 
zinc (on long soaking), and bright blue only in a few cells and parts of 
cells with Russow's test. 

Ps. campestris also made a prompt and copious growth on this sub- 
stratum, but there were some difl'erences. On the seventh day the 
growth, while very abundant, was scarcely distinguishable in color 
from the substratum; i. e., it was plainly less yellow than that of P.h. 
hyacinthi. At this date the fluid was grown full of the bacteria 



40 

(solidifiofl). Oil the eighteenth day the whole sabstratuni was browned 
and this color was a much deeper l)rown than in the corresponding 
tul)e of J's. hyaclntlii. On the fiftieth day the color was l)urnt umlier, 
and on the sixty-fourth day dark burnt uuiber. The slime was neu- 
tral or slighth' alkaline on the thirtj'-fourth day, and feebly alkaline 
on the sixt3'-fourth da}". The tissues were softened. 

On this substratum Ps. stewarti made a thin buff yellow, slightly 
iridescent growth. On the seventh day there Avas one-fifth as much 
growth as in corresponding tubes of P>i. hyaeintJu and one-tenth as 
much as in Ps. camjjestrls. Growth did not increase much after the 
first or second week, and there was no browning or softening of the 
substratum. The culture was alkaline on the thirty-fourth and sixty- 
fourth daj's. After a time the water surrounding the turnip contained a 
moderate amount of buft" yellow precipitate, but it never became thick 
or solid from excessive multiplication of the bacteria. 

Rutabaga. 

Test-tube cultures of this turnip (which had smooth glaucous leaves) 
were prepared with distilled water in the ordinary way (see Potato). 
The tests were made at the same time and in the same manner as on 
the 3"ellow globe turnip, and the results were much the same. 

With ^s-. hyacintJil the growth was copious from the start, and not 
onh' covered the cylinder, but filled the fluid (solid). There was no 
stain of the substratum until after the twentj^-seventh da}', but this 
was covered by the bacterial growth so as not to be exposed any- 
where directly to the air. On the fiftieth da}^ the bacterial slime exhib- 
ited a smooth, wet, dirty, brownish yellow surface. The upper part 
of the sul)stratum was now browned. The slime was acid to neutral 
litmus, leaving a distinct reddish color as it dried, ajid the cylinder was 
softened so that it mashed easih" with a glass rod. The fluid was still 
plainl}' acid after adding 25 c. c. of water and stirring. On boiling 
only a trace of acid was given off in the steam. On continuing the 
boiling so that the fluid was reduced to 6 c. c. it was more strongly 
acid, and the acidit}' became still more pronounced on reducing it to 3 
c. c. The boiled fluid had a slighth' bitter taste. There was a slow 
evolution of gas and no white precipitate when this rather thick slime 
was put into barium chloride water (acid). 

On this substratum Ps. campestrtx grew ver}' promptly. By the 
seventh day the fluid was grown solid and the cylinder in the air bore 
on all parts a very copious, wet, shining, smooth, yellow growth. At 
this time there was alread}- a slight stain of the substratum. This 
stain became more pronounced and extended to the whole substratum 
on or before the eighteenth day. This color (slime and substratum) 
gradualh' deepened through raw umber (fiftieth da}-) to mummy brown 
(sixty-fourth day). On the thirty-fourth and sixty-fourth days the 



41 

thick slime was acid to litmus, especiaH^^ when diluted with distilled 
water. The tissues were softened and there was a peculiar smell, which 
was not rank or strong. 

The l)ehavior of Ps. stevjarti on this substratum differed from that 
of Ps. hyacintJd and Ps. campestHs in the same way as on the yellow 
globe turnip and was even more pronounced, so that it might be used 
as a means of distinguishing these organisms. The growth on the 
seventh da}^ was about one-tenth as much as Ps. kyacinthi and one- 
twentieth or one-thirtieth as much as Ps. carnpestris. 

On the eighteenth day the differences were as follows: 

Ps. stevxvrt'i : Growth, buff yellow, thin, covering the whole of the 
air-exposed surface, but not dense enough to hide the slight irregu- 
larities of the substratum (not smooth). Surface slightly iridescent 
and with fine striaj (Zeiss X 6 aplanat), precipitate buff yellow and 
moderate in amount, water not grown full of the solid 3'ellow slime, 
substratum not browned. 

Ps. hyacinthi and Ps. carnpestris: Slime in the air copious, smooth, 
ver}' wet-shining, pale yellow, surface not iridescent. Fluid grown 
full of the yellow slime (solidified). Substratum browned or read}^ to 
brown. 

In old cultures of Ps. stcirarti there was no increased growth, no 
brown stain, and no softening of the tissues. On the thirty-fourth 
da}' the thick slime would not wet litmus paper until water was added, 
when it gave an alkaline reaction. On the sixty-fourth day there was 
"a peculiar smell" and a feebly alkaline reaction. The iridescence 
persisted. 

Carrot. 

Cylinders of carrot were prepared in the same wa}' as the potato 
cylinders. 

Ps. hyacinthi grew well on this medium at 20° to 23° C. , and gen- 
erally without any distinct retardation. Usually growth was visible 
on the third day, and continued for several weeks, covering the aerial 
part of the cylinder with a bacterial layer a millimeter thick. The 
fluid in the bottom of the tube (1 to 2 c. c.) was also filled with a thick 
yelloAV slime, so that after 3 weeks it could usually be turned bot- 
tom up without flowing. Generally, though not always, growth was 
copious enough by the end of the first week to obscure the oi*ange red 
of the substratum, which was not the case with Ps. camjjcstris. 

The surface was always wet-shining, even in very old cultures. In 
some it was smooth and homogeneous-looking from the start, and 
remained so. In others the surface was shagreened at first, but after 
eight days became smooth and homogeneous-looking. The bacterial 
slime was not sticky on the eighth da}', in which particular it is very 
unlike Bacilhis tracheiphihis. Subsequently (thirty-first and sixty- 
seventh days) it became slightly sticky. 



42 

The color on the fifth day was " bright yellow." On the eighth day 
it was between chrome yellow and maize yellow (R. VI-8 and 21). 
These two colors are compounded of varying amounts of orange cad- 
mium, pale cadmium, and white. The slime in old cultures became 
dark(U', as if from admixture with a brown stain. On the thirty -fir.st 
day the color was between ochraceous and raw sienna (R. V-2), being 
near the latter color. After sixty-nine days the slime in one tube was 
noted as "dark yellow" and in another as ochraceous to tawny ochra- 
ceous. In one of these tubes the carrot was observed to be decidedly 
deeper orange than when it was inoculated; i. e., than check tubes. 
On the fourteenth day the color and general appearance of this slims 
closely resembled that of a culture of Ps.jjhnseoli made for comparison. 

On the eighth and twenty-third days the slime was distinctly alka- 
line to neutral litmus paper. On the same da}^ the slime was more 
alkaline in a tube 31 days old than in one of the same age and origin, 
but in which the organism had grown for onl}' 23 days; i. e., was 
restrained from growth by heat during the first week. In a culture 
67 daj'S old the slime was plainly alkaline. 

After two and one-half months'' growth, the carrot cylinders retained 
their form perfectly (2 tubes), but went into pulp easily under pres- 
sure of the fingers, as if the middle lamella had been partially dis- 
solved. These cylinders had a soapy-feeling, and a feeble but distinct 
smell suggestive of ammonia and amin compounds. 

In one instance crystals or crj^stal-like bodies were observed in the 
slime of old cultures (09 days). 

Penicillium grew readily on carrot covered by this organism, was 
found associated with it in a number of the l)ulbs received from the 
Netherlands, and is mentioned by Dr. Wakker as sometimes occurring 
in badly affected Indbs. 

A repetition of the carrot cultures in 1899 led to similar results. 

In two test-tube cidtures which were examined after seventy-two 
days the growth appeared to be tj^pical for Ps. hyacinthi^ but in one 
the carrot was browned and in the other not. In both cultures there 
was a feeble smell, like glue; in both the cylinders were softened and 
went to pieces under slight pressure of the fingers. In the one which 
was not browned the carrot was distinctl}" but feebh' acid to neutral 
litmus paper (it was also acid on the fortj'-second day). In the other 
the surface slime was neutral to litmus (it was alkaline on the fortj"- 
second day). The interior of the carrot was also neutral or nearly so. 
Lead acetate- paper placed for six weeks in the mouth of this tube, 
below the cotton plug, was not browned. The C3dinders are believed 
to have been derived from different carrots. Both cultures were 
inoculated from the same tube. The difference in brown staining is 
believed to be attributable to slight differences in the chemical com- 
position of the carrots. (See Ps. phaseoli under The Brown Pigment.) 



48 



Sweet Potato. 



This medium was prepared in the same wa3^ as the common potato. 

Ps. hyacinth! orew well upon it and with little, if any, retardation. 
Usually, by the end of the first week, at 18^ to 25'^ C, the growth on 
the aerial part was copious. This growth did not stop early, as in case 
of the common potato, but continued for a long time, covering the 
whole of the exposed part and filling up the water with a solid yellow 
slime. In one set of cultures, at the end of the twent3"-second day, 
the growth was 10 times as abundant as on the common potato, and on 
the fift3^-sixth day 100 times as abundant. In another set of cultures, 
made some months later, there was "much more growth than takes 
place on the Irish potato." Usuall}^, by the end of the third week, 
the 1 to 2 c. c. of water in the bottom of the tube was grown full of 
the yellow slime, so as not to flow when tilted. 

The surface of this growth was wet-shining even in old cultures (55 
days). At first the surface was smooth, but after some weeks it 
became unev^en, i. e. , thickly set with smooth-roundish prominences, 
which appearance I have designated as shagreen. This uneven surface 
remained wet-shining and homogeneous in color, and I have no doubt 
as to the purity of the culture. Even in cultures not older than one 
week the bacterial mass did not readily dissolve or shake apart in 
water. 

The color of Pa. hyacinthi on this substratum at the end of the first 
week was wax-yellow to gamboge-yellow in one set of tubes and in 
another it was '* bright-yellow." On the thirty-first da}" the slime was 
slightly sticky and its color in mass, on white paper, was maize-yel- 
low. Examined microscopically at this time there were no spores but 
a great many slender chains (6 to 12 rods) mixed in with zooglcete and 
single and paired rods. After 55 da3's the slime in one set of tubes 
was "dull-3'ellow" and in another set "dirt3" 3'ellow," but there was 
no distinct brown pigment. At this time, in one set of tubes, the 
slime consisted of a mixture of long and short rods, chains, and zoo- 
gloese. Some of the rods and chains were ver}' long, extending one- 
sixth to one-fifth of the way across the field of the microscope (Zeiss 
-t nun. apochromatic and 12 compensating ocular). At this time, in 
the other set of tubes, there were numerous roundish zooglcese embed- 
ded in the bacterial la3'er. These zoogloea? were a little whiter than 
the body of the slime and dissolved slowl}' in water. Under the micro- 
scope they presented the same appearance as all the zooglcBie of this 
organism, and I had no reason to suspect contamination. 

An acid appears to be formed out of this substratum. After 31 
da3's the slime from the bottom of a tube showed no alkaline reaction, 
])ut was neutral to good neutral litnuis paper. After 56 days slime 
from the same cultures was still " neutral or slightly acid'" to litmus, 



44 

there being- no alkaline reaction whatever (2 tubes). After 55 days' 
growth the slime from another set of tubes showed no trace of alka- 
line reaction. That from one tu])e was "neutral or slightly acid"" 
when stirred up in a drop of distilled water and tested with neutral 
litmus-paper, while that from another tube was "feebly acid.'' These 
results may ))e compared with those obtained from old cultures on 
common potato. 

Sugar Beet. 

The white sugar beet was prepared for use in the same way as the 
potato cjdinders. 

Ps. hyacintld grew copiously on this medium and for a very long 
time. Usually, at 20'^ to 25'^ C, growth was visible by the end of the 
fourth day, and sooner if very copious inoculations were made; but 
in some instances growth did not appear until the sixth da}^ i. e., 
there was some retardation. Once, on rather dry cylinders 3 months 
old, the germ refused to grow, although it grew promptly in check 
tubes of freshly prepared coconut. Moreover, although inoculated 
very copiously on several different occasions, the organism could not 
be induced to grow in a flask containing several hundred grams of 
ground ]>eets covered with 100 c. c. of distilled water. This failure was 
attributed to the acidity of the beet juice, since the organism grew 
readily in another flask, which was prepared at the same time and from 
the same beets, and differed from the preceding flask only in having 
the flrst 100 c. c. of water poured ott' after some hours and another 100 
c. c. added. 

Generally, by the end of the first week, the whole or nearly the 
whole of the aerial part of the cylinder was covered, but the early 
growth was not as copious as in corresponding tubes of P^. cahtpestrk. 
In time this growth became very copious, and the fluid gradually 
filled up with a solid yellow slime. In 20 days (2 tubes) the growth 
was "much better" than on potato. In 22 days (another series) 
the growth was 3 times as much, and in 31 days 20 times as 
much as on potato. In 37 days (another series) there was a copious 
growth over the whole cylinder, and the fluid in the bottom (1 to 2 
c. c.) was full of the yellow slime, there being at least 50 times as 
much development as on the potato. Judging from its appearance, 
this culture continued to grow for another month. After 65 days 
(another series) there was a much better growth than on potato. The 
growth in the air was copious, but not all of the fluid was filled with 
the slime. After 52 days (another series) the beet cylinder was 
entirely covered with a very copious growth and the fluid around the 
lower one-half was filled full of a yellow slime, exactly as if it were 
the cabbage or bean parasite growing on potato. In tubes of potato, 
inoculated at the same time from the same culture, the organism had 



45 

niiidc only a feeble to moderate growth and had formed no yellow 
slime in the water, the contrast being very striking. After 135 days 
this culture on sugar beet was still fresh-looking, and the solid yellow 
slime where the water had been was 2 cm. deep. 

The surface of this growth was always wet-shining, but sometimes 
it was smooth and at other times shagreened. Of two cultures exam- 
ined on the fifth day, the one grown at room temperature was smooth, 
th(^ one kept in the thermostat was shagreened. Of two other cultures 
examined on the twenty-second and thirtieth days, both grown at room 
temperatures, one was smooth and the other was shagreened, i. e., 
thickly set with smooth, roundish papilL^, which appeared gelatinous 
to the eye but lifted out readily when touched with the loop. The 
smooth culture was paler yellow than the other. Portions of the latter 
did not dissolve readily in water. Under the microscope this culture 
appeared to be all one thing. In a pale-yellow culture 30 days old 
there were no spores, but many dense aggregates (zoogloea?) not readily 
dissolving in water. The rods were short and slender, and no chains 
or motile elements were visible. In the same culture, after 55 days, 
there were colonies or zoogkp{\? in the surface slime. These had 
roundish margins and were paler yellow than the body of the slime. 
In a beaker of water they did not dissolv^e in one-half hour. 

At first the cultures were not sticky (8 days), but eventually they 
became slightly stringy (30 days). 

The color of the growth was distinctly yellow from the start, in most 
cases becoming })right yellow. In mass on white paper, on the eighth 
day, this color was between gamboge yellow and chrome yellow (Ridg- 
way). After 21 days another culture was gamboge yellow and was 
several shades brighter than a corresponding culture on potato. After 
17 davs in the thermostat the color was "dull yellow." One culture 
remained pale yellow for 57 days. Several others grown at room tem- 
peratures were bright yellow after 2 months, and one was noted as 
still bright 3^ellow at the end of 135 days. 

Tubes inoculated from a culture 52 days old took readily, showing 
that a considerable portion of the culture was living. 

An acid seems to be slowly developed in small quantities by the 
growth of the organism on this substratum. In one tube, at the end 
of 7 days, there was no acid reaction, the fluid being feebly alkaline 
to neutral litmus paper. On the eighth day, in a tube from another 
series, the slime was not alkaline and not acid, but exactly neutral. 
After 21 days, in a tu))e from another series, the fluid was feebly 
alkaline. On the thirtieth day, in cultures of another series, the 
vellow surface slime was not alkaline, but neutral or slightlv acid. 
The lluid in the hottoni of this tu))e was neutral, but the paper red- 
dened on drying. The fluid, however, from a check tube was also 
neutral at first, but was e(iually and plainly acid when dry. After 



46 

55 days the yellow slime on the aerial part of the c^'linder and the 
fluid in the bottom of this tube were both acid. There was no trace 
of any alkaline reaction, but this acidit}^ was feeble, i. e., not much, 
if an}^, more pronounced than in the dried-out juice of the check 
tubes. On the thirtieth day, in another tube of the same series, a 
mass of germs from the top of the cylinder reacted feebly acid, or at 
least there was no alkaline reaction on neutral litnuis paper. After 
55 days a large loop of yellow slime from the same tube showed no 
alkaline reaction when rul)bed on neutral litnuis paper, not even 
when stirred up in a drop of distilled water. At the same time no 
acid reaction could ])e detected. The slime was neutral. 

No brown stain appeared in an}^ of these cultures (67 da3^s). 

See also Fee])le diastasic action and Relative nutrient vahie of carbon 
compounds for additional notes on growth on solid media. 

SENSITIVENESS TO ACIDS. 

The failure of /*.y. hyacintld to produce any inmiediate s^'mptoms, 
even when inserted into the hyacinth-leaf parenchyma by the million, 
the slow progress of the disease when it tinally appeared, and the 
extent to which growth is restricted to the immediate vicinity of the 
vascular )>undles, have been described in Bulletin No. 26. This behavior 
of the organism in the host plant, which resembles that of Ps. cani- 
pestris in the turnip and cabbage, led me to suspect it might be xqyj 
sensitive to acids. To test this supposition the following experiments 
were made: 

Acu) Beef Broths. 

In all cases the rate of growth in beef broth made neutral to phenol- 
phthalein was assumed as the standard. 

(1) The first trials were with stocks 286a, 286b, and 286d. Stock 
286a was a 1:2 beef broth, to which no sodium chloride or alkali was 
added, and the acidity of which was -f-25 of Fuller's scale. Stock 
286b was a portion of the same broth rendered neutral to phenol- 
phthalein (0 of Fuller's scale), by caustic soda. Stock 286d was a por- 
tion of 286a boiled down so that it was quite yellow and strongly acid, 
i, e., -|-80 of Fuller's scale. Each tube contained 10 c. c. of broth. 
All were inoculated at the same time from an alkaline beef -broth cul- 
ture 4 days old, and were kept together in feeble light, at room tem- 
peratures of 20"^ to 24° C. 

Besult. — The alkaline broth (286b) clouded in 26 to 72 hours, accord- 
ing as the infection was made with a large loop or with a tiny drop 
from the tip of a platinum needle. Stock 286a (feebly acid) clouded 
in 48 to 168 hours, according to manner of infection (loop or needle). 
Stock 286d, whichever way inoculated, remained clear until the close 
of the experiment (49 days). 



47 

(l2) Stock 30(\' was an old, partially evaporated flask of 286d brought 
back to its original volume b}' adding' distilled water. Its acidity 
was +80; i. e.. exactly 80 c. c. of ^ NaOH would have been required 
to neutralize 1 liter, using phenolphthalein as the indicator. Stock 
3001) was a portion of 300c diluted with an equal l)ulk of distilled 
water, so that its acidity was reduced to +40. Stock 300a consisted 
of ;i portion of 300c diluted with twice its bulk of distilled water, the 
acidit}' being consequently reduced to about +27, Three tubes of 
each stock were inoculated from an alkaline beef -broth culture 11 days 
old. All of the tubes were kept together in feeble, diffused light, in 
well-plugged tubes of resistant glass, at room temperatures of 20*^ to 
23'' C. Two of each set were inoculated with large loops, the third 
with a tiny dro}) from the tip of a needle. 

liesult. — In 300c there was no growth whatever (21 days). In 300b 
growth was nmch retarded, the fluid remaining clear for 8 days, and 
probably for a much longer period. On the twenty -first da}^ when 
next examined, the two tubes inoculated b}- loop were feebl}' clouded, 
and showed a moderate amount of 3^ellow precipitate. There were 
also quite a good many large ^^ellowish flecks (zoogkjeae), on the walls 
and floating in the fluid. In the tube inoculated by needle the cloud- 
ing was veri/ feel)le, there Avas only a .s//(7//?' precipitate, and there were 
no zooglo3?e. On the twentj^-fifth day the fluid in the needle culture was 
neutral to sensitive neutral litmus paper, while in the loop cultures it 
had become feebly alkaline. In 300a clouding was visible on the sixth 
day in the loop cultures, and on the eighth day in the needle culture. 
Here also growth was retarded, but not so long as in 300b; e. g., on 
the twentv-first day the tube of 300a, which was inoculated by needle, 
was about twice as cloudy, and contained ten times as much precipi- 
tate as the tubes of 300b, which were inoculated by loop. The organ- 
ism changed the fluids from acid to alkaline, and in the end (55 days) 
all of the cultures were much alike. 

(3) The last experiment was repeated, more attention l)eing paid to 
the time of first clouding in 300b. Each tube contained, as usual, 10 
c. c. of broth, was tightly plugged, was inoculated with one loop {oese 
2 mm. in diameter) from an alkaline beef broth culture 12 days old, 
and was set away in feeble light at room temperatures of 19'^ to 26° 
C. (mostly 20'=' to 21^ C. during the first 6 days). 

ReKnlf. — In 300a clouding was first visible on the sixth day, but was 
then very feeble. In 300b the fluid remained perfectly clear for 1!) 
days. On the twenty-sixth day, when next examined, it was feebly 
clouded. In 300c there was never any growth (20 days). 

Pfi. eampestris^ Ps. p/iaseoli, and BacUliiH amylovorm also refused to 
grow in 300c. On the contrary, Pn. stewarti^ inoculated from a solid 
culture, grew in it for a long time and very luxuriant!}-, although 
clouding did not appear until the eighth day. 



48 



Lactic Acid. 



Schering's diabetinc (fructose) in 1 j^rani doses was added to test 
tubes containing 10 c. c. portions of standard nutrient agar (acidity 
+ 15.5 of Fuller's scale), on which Ps. hyacintld was known to grow 
well. This agar was resterilized, slanted, and inoculated b}- streak- 
ing, but no growth could be obtained (58 days). The inoculation was 
from an agar culture 13 days old, a large loop of the 3"ellow slime of 
Ps. hyacinthl being rubbed thoroughly over the whole surface. That 
the culture used for inoculation was alive was shown by the fact that an 
inoculation therefrom into the san)e agar without the sugar produced 
a decided growth in 24 hours. This fructose agar was distincth^ acid 
to neutral litmus paper, owing presumably to the presence of a small 
amount of lactic acid which is said by the manufacturers to be put into 
the sugar to improve its keeping qualities. Ten grams of this sugar 
required 10 c. c. of /„ NaOH to render it moderately alkaline to litmus. 
When 0.7 c. c. and 1.0 c. c. portions of this alkaline sirup were added 
to tubes of this agar a substratum was obtained on which, after a 
time, the organism grew luxuriantly. The inoculations were made 
with a loop of slime from solid cultures. In the 0.7 c. c. tubes, growth 
was feeble during the first 4 or 5 days, then excellent and long-con- 
tinued. In the 1.0 c. c. tubes, growth at the end of 7 da3\s was still 
very feeble, i. e., not one one hundredth as much as in the tubes 
containing onl}'^ seven-tenths as much of the alkaline sugar. On the 
twelfth da}" there was about one-third as much growth; on the six- 
teenth day growth had much increased. After this the 2 sets of tubes 
looked much alike and the growth was at least 10 times as abundant 
as on the same agar without the sugar. 

Potato Broth. 

This broth was half strength, i. e., VA. It was made by putting 500 
grams of thinly sliced potatoes into 1,000 c. c. of distilled water 
and heating on a water bath 2 hours at 10° to 55^^ C. The broth was 
then filtered, steamed one hour, cooled, made up to 2,000 c. c, filtered, 
tirated, and divided. Its acidity was +30 of Fuller's scale. For 
comparison, a portion of this l)roth received enough caustic soda to 
make it +24, another portion received one-third as much soda and 
registered an acidity of +2S, a third portion received 1 per cent of 
Witte's peptonum siccum. This last was not titrated, but the peptone 
is known to give an alkaline reaction with litmus, and this addition 
must have considerably reduced the acidit}' of the fluid. 

(1) Each tube contained 10 c. c. of ])roth and was well plugged. 
All were inoculated at the same time and were kept together in feeble 
diffused light, at room temperatures ranging from 20'^ to 25^^ C. Each 
tu])e was inoculated with a large loop from a well clouded alkaline 
beef broth culture 11 days old. 



49 

BesulL— The simple potato broth (+30) powerfully retarded the 
growth of Fs. hyacinthi, the fluid remaining perfectly clear for 8 
days, and probably much longer. On the twenty -fourth day, when 
next examined, the fluid was clouded, showed some precipitate and 
had become alkaline. The +24 and +28 broths were both feebly 
clouded in 72 hours. The peptone potato broth must have clouded 
somewhat earlier than the last two, as it showed distinctly more 
growth at the end of the third day. Query: What was the inhibiting 
substance represented by the difference between +30 and +28 and 
removed by the addition of this small amount of sodium hydrate? 
Could it be oxalic acid ? 

(2) The preceding experiment was repeated, all of the conditions 
remaining the same, except that fewer germs were put into the tubes. 
The inoculations were from an alkaline beef broth culture 12 days old, 
and each tube received a moderate sized loop instead of a large loop. 

Remit.— In the +30 broth, which was feebly acid to litmus, no 
growth ever appeared (31 days). In the +24 broth a very feeble 
clouding was visible in 68 hours. In the +28 broth clouding was 
visible in 44 hours. Feeble clouding also appeared within 44 hours 
in the peptone potato broth. 

Ps. campestris and Ph. phaseoU also refused to grow in the +30 
broth. Ps. stewarti grew in it readily. 

Malic Acid. 

This acid was added to gelatins (see Nutrient gelatins) and to the 
potato broth already described. A portion of this potato broth was 
measured out and enough of this substance was added to raise the acidity 
of the broth from +30 to +45. A tube was inoculated with a large loop 
of Ps. hyacinthi from the same culture used for the first potato-broth 
experiments. The tube was exposed to the same favorable conditions 
as the potato-broth tu})es, but no growth ever appeared (55 days). A 
month later the experiment was repeated, inoculating with a moderate 
sized loop from the culture used for the second potato-broth experi- 
ments. This tube was subject to the same conditions as the latter, but 
no growth ever appeared (31 days). A month later, 2 more tubes 
were incK'ulated, using an enormous number of germs, viz, for each 
tube a mass of bright yellow slime 2 mm. in diameter, which was 
taken from the fresh surface of a starch-jelly culture 9 days old. 
These well-plugged tubes were kept in very feeble diffused light, at 
room temperatures of 23° to 30° C, but no growth ever appeared 
(80 days). 

Ps. campestris and Ph. phaseoli also refused to grow in this broth. 
On the contrary, BacillxLS amylovorus., inoculated from a colony, 
clouded it in 48 hours and in the end made a better growth in it than 
21788— No. 28—01 4 



50 

in alkaline beef broth. Ps. steivartl grew in this broth without 
retardation. Three .saprophytic bacteria, obtained by Mr. A. F. 
Woods from the surface of carnation leaves, also clouded this broth 
in 2 to 7 days, viz, a pink buff germ, a lemon yellow germ, and an 
orange colored germ, the latter probably identical with Bacterium 
diaiithi AYt\\\x\' and Bolley. (See also Growth in fluid media.) 

Cabbagk Juice. 

This fluid was prepared by grinding green cabbage leaves and 
extracting the juice under pressure. No water was added. The leaves 
were from old, slow-growing, hothouse plants. This juice was 
divided into two portions, one of which was sterilized by forcing it 
through a Chamberland filter, and the other b}^ steaming for a few 
minutes on 3 consecutive da} s. There was no difference in the acidity, 
each titrating +40 with caustic soda and phenolphthalein. The boiled 
juice smelled strongly of cabbage. Each stock was inoculated in the 
same way, i. e., with a small mass of bright yellow slime from a 
starch-jelh' culture 28 days old. The tubes were well plugged and 
set in a dark place exposed to room temperatures of 22° to 33° C. 
(mostly 25° to 29°). 

Result. — One tube of the filtered juice was under observation 44 
days, but no growth appeared. Two tubes of the boiled juice were 
under observation, respectivel}", 29 and 44 daj^s, but there was no 
growth. Five tubes of slant agar were inoculated at the same time 
from the same culture, and all took readih'. Knowing that bac- 
teria will tolerate more acid in a solid than in a fluid medium, 150 
mgs. of Lautenschlager's neutral agar flour was added to one of 
the tubes on the twenty-ninth day. This was then steam sterilized, 
slanted, and the surface carefull}" streaked with at least a cubic milli- 
meter of bright yellow slime from an agar culture 4 da^^s old. This 
slant culture was under observation, in conditions favorable to growth, 
for 45 days, but no growth ensued, except on the wall of the tube above 
the slant in a place which Avas accidentalh" touched by the loop and 
where a little moisture condensed. 

Ps. 2)J(CLseoh' and Ps. campestris also refused to grow in this acid 
cabbage juice; but when the fluid was solidified b}" adding 150 mgs. of 
the agar flour the latter made a ver}- copious and prolonged growth — 
i. e., much better than on ordinar}- agar, although it was started upon 
it with great difliculty (3 copious inoculations). On the contrary. 
Bacillus amylovorus and Ps. stewarti grew in the boiled juice without 
retardation. The latter, inoculated from a solid culture, clouded the 
fluid (2 tubes) in less than 48 hours iind made a ver}' prolonged and 
copious growth. B. amylovorus grew nearl}' as well. 



51 



Tomato Juices. 



Four tomato juices were tried, all from fruits of thrift}^ hot-house 
plants of one variety (Lorillard). The fruits were picked and sorted 
into groups as follows: (1) Stock 331, fruits red and ripe, with a fine 
odor, excellent for the table; (2) stock 332, fruits full grown and 3'el- 
lowish-green, i. e., commencing to ripen; (3) stock 333, fruits entirely 
green, but nearly or quite full grown; (4) stock 331, small green fruits, 
one-twentieth to one-fourth grown. The juices were olitained by 
pulping the fruits and extractmg imder pressure. These fluids were 
then filtered, steamed, filtered, filled into tubes, and sterilized ))y steam- 
ing 10 minutes on 2 consecutive days and 15 minutes on the fourth day. 
Each juice was carefully titrated for acidity and sugar content. Starch 
was abundant in the green fruits, but there was ver}' little in the yel- 
lowish-green fruits and none whatever in the ripe fruits. Grape sugar 
was most abundant in the yellowish-green fruits. The acidity of the 
yellowish-green and of the ripe fruits was nearly the same, but 
undoubtedly thej^ contained more than one acid, and the proportions 
were probably different. Each of these stocks was inoculated with at 
least one-half cubic millimeter of the yellow slime of P.s. hyacinthi 
from a coconut culture 7 days old, a check inoculation (which grew 
promptlv) being made into alkaline beef broth. All of the tubes were 
kept together in feeble difl'used light' at room temperatures which 
ranged from 22° to 34° C. (mostly 25° to 28°) during the first 25 days, 
and after that 29° to 35° C, and occasionally for a few hours as high 
as 37° (Washington summer heat). The results obtained are given 
below : 

(1) Stock 331. No growth (35 days). The acidity of the stock was +64, and the 
sugar content was such that 2.5 c. c. were required to reduce 5 c. c. of the standard 
solution of CuSO^ 5H./J in Soxhlet's sohition. 

(2) Stock 332. No growth (35 days). The acidity of this stock was ^68, and the 
sugar content was such that only 1.8 c. <•. were required to reduce 5 c. c. of the 
standard solution of CUSO4 5H2O. 

(3) Stock 333. No growth (35 days). The acidity of this .stock was +55, and the 
sugar content was such that 3.7 c. c. were required to reduce 5 c. c. of the standard 
solution of CUSO4 5H,0. 

(4) Stock 334. No growth (35 days). The acidity of this stock was +59, and the 
sugar content was such that 2.2 c. (;. were required to reduce 5 c. c. of the standard 
solution of CuSO^ 5H,0. 

The acidity here recorded marks the first perceptible trace of change 

N 
of color on adding vTjNaOH drop by drop to 5 c. c. of the juice in 50 

c. c. of water plus 1 c. c. of the standard alcoholic solution of phiMiol- 
phthalein. More alkali was re({uired to produce a bright pink, and, if 
this ))e taken as the standard color, th(;n the readings would bo, respec- 
tively, + 71, +75, +05, and +72. Still more alkali was required to 



52 

produce a red which could not be made deeper. The readings when 
addition of more alkali did not deepen the color were, respectively, 
+111, +88, +81, and +93. 

In each case these figures are the average of three titrations at room 
temperatures. Titrated boiling hot, each of the fluids required con- 
siderabh" more alkali. 

Ps. campestris, Ps. phmeoli^ Bacillus amylovoriis^ and B. olem also 
refused to grow in these juices. On the contrary, stocks 333 and 331 
were well clouded by Ps. stewarti on the fifth day, and 331 became 
well clouded some time between the eighth and fifteenth day. In each 
of these 3 fluids this organism made a copious and prolonged growth, 
but it refused to grow in 332, although this contained more sugar than 
the other stocks; and even when reinoculated copiously from 331, after 
the latter had become well clouded, it remained clear. It is probable, 
therefore, that the limit of toleration of Ps. stevMrti for the acids of 
the tomato lies between +61 and +68. 

Hyacinth Broth. 

Perhaps the most interesting result of all was obtained with hyacinth 
broth. This was made from 13 rather small l)ulbs of a single-flowered 
white variety of Ilyacmthus orientalis. The bulbs had been kept 
in a closet in the laboratory all winter and had lost some water, but 
were not shriveled. In March the plateaus were removed (the most 
alkaline part of the bulbs) and the remainders were pulped and an 
effort made to extract the juice. Only a very sticky slime oozed 
throuoh the ))ao\ and this would not flow. I then added 100 c. c. of 
distilled water and squeezed out as much juice as possible under an 
iron press. An endeavor was made to pass the fluid through a Cham- 
berland filter, but it would not go through with a pressure of 25 
pounds per square inch. The fluid was then thoroughly steamed and 
filled into test tubes after filtering out a very copious white coagulum, 
consisting principall}^ of nitrogenous substances, starch, and raphides. 
There resulted a hazy, yellow, acid fluid, which never precipitated 
entirely clear. Titrated with caustic soda and phenolphthalein, 1 c. c. 

N 
exactly balanced 0.28 c. c. of j^NaOH (first trace of color), and con- 
sequently the acidity was +28 of Fuller's scale. Pushed far enough 
to give a bright pink, the reading was +10. This fluid was moder- 
ately acid to neutral litmus paper. Four clean, well -plugged tubes, 
each containing 10 c. c. of this fluid, were inoculated with a large loop 
of Ps. hyacinthi from an alkaline beef-broth culture 2 days old, which 
broth was inoculated from a solid cultore and had been cloudy for 21 
hours. The tubes were kept in a dark place at room temperatures 
very suitable for growth, viz, 19*^ to 25"" C. 



53 

Bemdt. — This fluid exerted a profound restraining influence. In 
two of the tubes the first bacterial clouding appeared on the seven- 
teenth day, at which time there was no rim of germs, pellicle, or pre- 
cipitate. The other 2 tubes were not clouded on the seventeenth 
day, but on the thirty-seventh day, when next examined, there was a 
copious growth in each. A large loop taken from each of these 2 tubes 
on the eighth day and put into tubes of alkaline beef broth did not 
cloud the latter until the fifth day, from which we may infer that 
multiplication had gone on in the acid broth very slowly. When once 
the restraining influence was overcome, the organism ran riot in the 
fluid making a magnificent and long continued growth, more growth in 
fact than I had been able to obtain with any other fluid. On the thirty- 
seventh day the fluid in each tube was plainly alkaline to litmus; there 
was no pellicle but a dense bright yellow rim i mm. wide, and a yel- 
low precipitate 5 to mm. deep. The rim was homogeneous, i. e., not 
composed of scattered yellow zoogloea^on a paler film, as was, however, 
the rim in tubes of alkaline beef broth inoculated directly from these 
cultures. This rim was wrinkled, or traversed crosswise, by many 
denser bands. The color of the bacteria was as bright as in the vessels 
of the host plant; compared with Ridgway's tables it exactly matched 
his chrome yellow (VI-S). On the fifty-second day all the tubes were 
alike. Each had a thick dark yellow ring above the fluid, and a copi 
ous, distinctly yellow pellicle. The fluid was nearly clear and dis- 
tinctly pale brown, which was not the case with the broth in theunin- 
oculated tubes. The yellow precipitate was three times as abundant as 
that obtained in alkaline beef broth, i. e., 6 to 7 mm. deep. The fluid 
was now strongly alkaline, and the germs were somewhat ropy. The 
cultures had a feeble, fishy odor suggestive of amin compounds. On 
boiling, gases were given off which immediately and strongly blued 
neutral litmus paper. Conducted into a tube of Nessler's solution, the 
vapor from the boiling fluid caused an immediate copious rusty pre- 
cipitate. The same result was obtained by putting one-fourth c.c. of 
the filtered fluid into Nessler's solution, but no such reaction could be 
obtained from the uninoculated fluid. An attempt was made to deter- 
mine the amount of alkalies present and the results are given, but I 
am not confident that either one is of any value. . The fluid did not 
redden with a small quantity of phenolphthalein, hut reacted with a 
larger quantity. Titrated in ice water with 6 c. c. of the standard solu- 

N 
tion of phenolphthalein, H c c. of the fluid required 0.20 c. c. of — HCl; 

N 
titrated with neutral litmus, 3 c. c. required 0. 30 c. c. of — HCl. It 

was difficult to drive off all the volatile alkalies by boiling, the blue 
reaction on wet litmus paper showing plainly in the steam when the 
fluid was half boiled away. 



54 

This experiment with hyacinth bi'oth was repeated, inoculating a 
tube of the same stock with a moderate-sized loop from an alkaline 
beef -broth culture 12 days old, i. e., with more germs. All the other 
conditions were the same. 

Besult. — The first trace of growth was on the fifteenth day. On 
the nineteenth day there were distinct rolling clouds and a yellow rim, 
but no precipitate. Subsequently there was a copious growth and a 
ver}'^ heav}' precipitate. No crystals formed. 

Ps. jplujLseoli and Ph. campestris both grew in this fluid, the latter 
much more readih^ than the h3^acinth germ. 

The discovery of this sensitiveness to acids furnished a satisfactory 
explanation of some perplexing contradictions obtained with unneu- 
tralized beef, potato, and cauliflower broths early in my stud}^ of Ps. 
hyacinthi. It also aflorded a partial explanation of the slow progress 
of the disease in the host plant, but apparently not a full one, since 
once well established in the vessels, it is not clear whv the parasite 
does not immediately advance into and destro}^ the acid parenchj-ma 
under cover of the alkalies which it produces. Evidently there are 
additional difliculties to be ov^ercome, one of which will be discussed 
in the following section. 

FEEBLE DIASTASIC ACTION. 

The meager development on cooked potato led to the belief that 
something in this substratum inhibited the growth of the h3'acinth 
organism. In the beginning it was thought that the feeble growth 
might be confined to certain varieties of potatoes and that on others a 
better growth could be obtained. To test this, cultures were made on a 
variety of tubers, new and old, but with the same result. Subsequently 
tubers were procured from a variety of soils and from climates as 
different as New York and Florida, but there was little difference in 
the amount of growth. The growth was comparatively feeble no 
matter what the age or origin of the potato. It was then thought 
that possibly the acidity of the potato might be the restraining cause, 
and dilute caustic soda was added to potato cylinders, so as to render 
them neutral or feebly alkaline after thej^ were steamed. On such 
c} linders the organism grew little if any better than on the untreated 
potatoes (-1:1 days), and this hypothesis was also abandoned. I then 
began to suspect that the feeble growth was wholly a matter of insuffi- 
cient nutrition, and found that on adding considerable quantities of 
cane sugar the growth increased rapidh' and became very abundant. 
About the same time tests with iodine showed that the starch of the 
potato, even close under the bacterial layer, had been very little acted 
upon by the organism. 

The rather meager growth of this germ on potato now appears to me 
attributable to its feeble diastasic action, i. e., to its inabilit)" to get 



55 

from the starch enough food for its normal growth, and I am surprised 
that this explanation did not occur to me at once. The organism grows 
fairly well until the small amount of grape sugar present in the potato 
is exhausted, and thereafter, when thrown wholly upon its own 
resources, makes only an extremely feeble growth, corresponding to 
its very feeble diastasic powers. This conclusion rests upon the fol- 
lowing experiments: 

Iodine Starch Reachton. 

My uninoculated potato cylinders when tested with iodine potas- 
sium iodide diluted with water, or with iodine crystals dissolved in 
absolute alcohol to saturation and then diluted with water as required 
for use, always yielded an immediate bright blue reaction. The starch 
reaction was also strong after the /^s. hyacintid had been grown on 
them for several weeks, although there was always evidence of slight 
diastasic action to be found in the purplish color assumed by some of 
the grains. The following are transeripts from my notes. 

(1) Some fragments of potato scraped from immediately under the 
yellow slime on a culture 30 days old were put into an old solution of 
iodine-glycerine. They became black at once, and when crushed out 
and examined under the microscope were brownish purple — i. e., more 
brown purple than the starch from a check tube. Tested with alcohol- 
iodine diluted with tifteen or twenty times its bulk of water, the starch 
of the potato in the check tubes became pure blue. In the culture, 
immediately under the yellow slime, most of the starch-bearing cells 
became purple, but occasionally one was nearly pure blue. Cells deep 
in the cylinder reacted blue. 

(2) On the thirty- first day another tube of the same lot was tested 
with alcohol-iodine, diluted with thirty or forty times its bulk of 
water. When this fluid was put on scrapings from a check tube, the 
reaction was pure blue; when it was put on scrapings from imme- 
diately under the yellow slime, the starch reaction was purple and blue 
purple. 

(3) A year previous scrapings were made close under the bacterial 
layer of a culture 30 days old and tested with iodine potassium iodide. 
There was a strong blue-black reaction. Under the microscope, how- 
ever, some of the cells were paler than others, indicating that some 
of the starch grains had been acted upon slightly. 

(4) On the twenty-ninth day a potato cylinder, bearing a typical 
growth of the yellow slime and uniformly grayed, w^as broken across 
the middle and tested with iodine alcohol in water. The middle part 
of the cylinder reacted l)lue. The outer pait, close under the bacte- 
rial layer, gave either a reddish or purplish blue reaction. 

No potato cultures of this organism were ever tested which did not 
give a very decided reaction with iodine. The importance of this fact 



56 

will be brought out to best advantage b}' comparison with Ps. cain- 
pestris or Ps. jphaseoU, both of which exert on starch a very powerful 
diastasic action. When either of these germs is grown on potato cyl- 
inders in water for 30 days, not simply all of the starch in the surface 
cells, but also all of that in the deeper parts of the cylinder, is acted 
upon, and this action is not feeble, but so vigorous and far-reaching that 
if the whole cylinder is crushed in a large bulk of the iodine water 
there is either no color reaction whatever, or merely in places a feeble 
brownish-purple tinge, indicating that all of the starch, or almost all, 
has been converted. 

Growth on Potato with Addition of Cane Sugar. 

These cylinders were the ordinarj^ potato cultures in test tubes, to 
each of which was added 1 gram of cane sugar. At first growth was 
retarded — e. g. , on the fourth day it was slight and white or nearly 
white. On the thirty-seventh day it was yellow, extended down into 
the fluid, and was 20 to 25 times as abundant as in the check tubes. 
The surface was wet-shining, but not smooth, owing to the protrusion 
of rounded zoogloeai. On the sixty-seventh da}" the slime was wax yel- 
low, and covered the whole cylinder, just as Ps. campestris or Ps. 
phaseoli would have done without the addition of sugar. The entire 
culture now looked like shagreen from inequalities in its surface due 
to the protrusion of rounded masses. The slime was neutral, or at 
least not alkaline, and the small amount of fluid remaining in the bot- 
tom of the tubes was plainly acid to neutral litmus paper. The brown 
stain of the fluid was less than in the check tubes. 

Growth on Potato with Addition of Maltose and Dextrine. 

This medium consisted of potato cylinders standing, two-thirds cov- 
ered with distilled water, in well-plugged test tubes. To each tube 
was added 100 milligrams of maltose and an equal quantity of dex- 
trine. They were then re-steamed as usual (20 minutes at 100'-' C, on 
3 consecutive days), constituting stock 301. Each tube was inoculated 
with a large loop of Ps. hyacinthi from a well-clouded beef-broth 
culture 11 days old, check tubes made from the same tuber being held 
for comparison. 

Result. — During the first few days (4 at least) there was not as 
much growth in the 2 maltose-dextrine tubes as in the 2 check tubes. 
However, at the end of 24 days (temperature 19° to 25° C.) there was 
an abundant yellow, wet-shining growth over the whole of the exposed 
part of the cylinder, down into the upper part of the water, and on 
the wall of the tube, at least 15 times as much growth as in the check 
tubes. This growth continued for several weeks. 



57 

Growth on Potato with Addition of Diastase of Malt. 

This medium consisted of 4 potato cylinders from the same tuber as 
301, to each of which was added 500 milligrams of Merck's " diastase 
of malt absolute." After remaining over night in a water bath at 50° 
C, these tubes were sterilized by steaming about 20 minutes on 4 
consecutive days. Each tube received a large loop from a beef-])roth 
culture 11 days old — the same tube that was used to inoculate the tubes 
of potato-maltose-dextrine. Two tubes without the disastase were 
inoculated for comparison. The tubes were kept together in the dark 
at room temperatures of 20" to 25° C. 

Result. — By the end of the third day the check tubes had developed 
a thin, distinct, yellow growth over nearly the whole of the exposed 
part (one-third) of the cylinder. The progress of these check cultures 
from this time on was typical for Fs. kyacmthi^ there never being any 
copious growth or any development of the yellow slime under the 
water. The tubes to which the diastase was added were under obser- 
vation 55 days. In 3 of them there was never any growth. In 
the fourth tube growth was retarded until the eighth day (tempera- 
tures 20° to 23° C), on which date a yellow patch 1 cm. square was 
visible. On the twenty- fourth day the organism had entirely overcome 
the retarding action of the medium and had made an abundant, dis- 
tinctly yellow, smooth, wet-shining growth over the whole cylinder 
down into the water and up on the wall of the tube. This growth was 
estimated at 50 times that in the check tubes and was greatl}^ in excess 
of any growth ever before obtained upon potato. 

The 3 tubes in which there had been no growth were reinoculated 
on the twenty-fourth day, using for one a large loop of 3^ellow slime 
from one of the check tabes, and for each of the other two an equally 
large loop of slime from the other check tube. This slime was rubbed 
carefully over the surface. No growth ensued, although the tubes 
were watched for a month. The fluid in these tubes was neutral to 
litmus, or very feebly acid when dry, and the restraining influence 
was therefore attributed to an excess of maltose or dextrine liberated 
by the diastase. On mashing one of these cNdinders in alcohol-iodine 
water there was no starch reaction whatever nor any red reaction. 

Potato Starch in Peptone Water with Diastase. 

This medium was prepared in test tubes of resistant glass, using about 
1 gram (estimated dry weight) of freshly prepared thoroughly washed 
potato starch to about 9 c. c. of distilled water which had received 4 per 
cent of Witte's peptonum siccum. The tubes were then put into the 
steamer and the starch solidified in a slanting position. Some of these 
tubes were held as checks, and the surface of the remainder was flooded 



58 

with about 1 c. c. of distilled water containing the commercial Taka- 
diastase. Each tube received 20 milligrams of this diastase, which was 
allowed to act U hours at 23^ C. and then destroyed b}^ steam heat. 
These tubes were then inoculated from three different cultures of Ps. 
ht/aemthl, a beef-broth culture 14 days old, a turnip culture 9 days 
old, and a carrot culture 9 days old. The fluid loops were streaked; 
the solid loops were rubbed carefully over the whole slant. The tubes 
were then kept in the dark at room temperatures ranging- from 19° 
to 23^ C. 

Result. — In the check tubes at the end of 48 hours there was a slight to 
very slight growth. On the eighteenth day from one-fourth to three- 
fourths of the slant surface in these tubes bore a thin Ijright yellow 
growth, which never increased nuich. The development of the germ 
in the tubes which received the diastase was plainly different. At the 
end of 48 hours the growth was distinctly yellow and much better than 
in the check tubes. On the ninth day the principal difference was still 
the amount of growth which was several times that in the check tubes. 
On the eighteenth day the growth was dirty yellow, wet-shining, and 
copious, i. e., at least 10 times as much as in the check tubes. The dif- 
ference in color was very decided. The slime in the check tubes was 
pure yellow; that in the others was dirty yellow, verging into brown- 
ish. The tubes were now thought to be rather too dry, and 2 c. c. of 
sterile Potomac River water was pipetted into each one, the result being 
a somewhat increased growth. On the forty -fourth da}^ the growth in 
the check tubes was still feeble and much less than in the tubes which 
received the diastase. The substratum of the latter had become brown- 
ish-white with the merest trace of pink in it. The same stain appeared 
in the check tubes, but was much feebler. 

Tubes of Ps. camj)estris and Ps. jyhaseoli yielded some instructive 
comparisons. In the check cultures, on the sixteenth day, the growth 
of these two germs was at least 20 times as abundant as that of Ps. 
Jtyacinthi. On the seventy-third day, in the check tubes, the layer 
of Ps. hyacinthi was still feeble, and was still distinctly yellow; 
that of Ps. campestris and Ps. phaseoU was 100 times as abundant and 
had lost all of its pure yellow color, this having changed into a decided 
brown. The starch in the check tubes of the hyacinth germ was as 
firm, elastic, and insoluble as when first inoculated, and was but little 
stained; that in the corresponding tubes of Ps. campestHs aad Ps. 
phaseoli was gray, soft-mushy, and soluble in water. Tested in alco- 
hol-iodine diluted with 50 volumes of distilled water, the check cultures 
of Ps. hyacinthi gave a strong starch reaction; those of Ps. cmnpestris 
and Ps. phaseoli gave no color reaction whatever. One culture of each 
was also tested with Soxhlet's solution for the presence of reducing sub- 
stances. Ps. campestris and Ps. phaseoli each reduced 25 c. c. of the 
standard solution of copper sulphate (34.639 grams of c. p. CuSO^ 5 H^O 



59 

in 500 c. c. of H.,0). The tests were made in the usual way with 5 c. c. 
portions of the copper sohition and 5 c. c. of the alkaline solution in 40 
0. c. of distilled water, boiling 2 minutes in white porcelain capsules. 
The check culture of P><. hi/acint/u was estimated to have reduced only 
a small fraction of 1 c. c. of the copper solution. On settling- there was 
only a little red precipitate and the fluid was still quite green-blue, so 
that perhaps not more than one one-thousandth of the starch was con- 
verted. The cabbage and the bean germ grew as well, or very nearly 
as well, on the peptone-potato starch without the diastase as with it, 
the cultures looking much alike. 

Inasmuch as the Taka-diastase contained a trace of some reducing 
substance and the peptone in water was able of itself to nourish the 
hyacinth germ for a time, it was thought best to repeat this experi- 
ment, using solutions of mineral salts, sodium asparaginate and ammo- 
nium lactate in place of the peptone, the same kind of starch, and a 
Taka-diastase, reprecipitated for me by Dr. John M. Francis. 

Nutrient Starch Jelly No. 1. 

This medium was prepared from Uschinsky's solution, substituting 
potato starch for the glycerine. My method of preparing this medium 
and the following one need not be given here, as it has been published 
in Proceedings of the American Association for the Advancement of 
Science, Boston meeting, 1898, page 411, and in Centralblatt fiir Bak- 
teriologie, 2. Abt., Bd. V, page 102. All that is necessary to say is 
that each tube contained from 5 to T c. c. of the solution and 1 to 1.5 
grams of the dry starch. After the starch had set and was ready for 
use the check tubes were counted out and the slant surface of the jelly 
in each of the others was flooded with 1 c. c. of distilled water contain- 
ing exactly 20 milligrams of the diastase. These tubes were then put 
into the thermostat at 34° C. for li hours, and afterwards the diastase 
was destroyed and the tubes sterilized in the usual way, i. e., by steam- 
in cf for a few minutes on 8 consecutive days. 

Before using, the diastase was carefully tested for the presence of 
reducing substances and found to be entirely free. This diastase like- 
wise gives no blue reaction with guaiac resin and hydrogen peroxide. 
The starch jelly was also tested in the same way, using Soxhlet's solu- 
tion, and was found to be entirely free from reducing substances. 
On the contrary, bits of starch jelly from the tubes which had been 
treated with the diastase gave an immediate rusty precipitate when 
dropped into the boiling fluid. 

Three tubes of this medium were inoculated, along with 3 check 
tubes. These 6 tubes were divivided into 3 lots, each group being 
inoculated from a separate culture. All were kept in the dark at 
room temperatures, which ranged from 19° to 25° C. during the first 
2 weeks and then from 25° to 34° C. (mostly 25° to 29°). 



60 

Result. — Two of these groups of tubes failed to catch and were 
reiuoculated later so that the first group will be considered by itself. 

(1) These 2 tubes were inoculated in the same way from a fluid 
culture 32 days old. During the first 18 da}' s there was no trace of 
color or sign of growth in the check tube. On the twenty-seventh 
day there was a slight growth with feeble yellowing of the surface, but 
careful scrutin}- was necessary to detect it. On the thirty-fifth day a 
slight increase of growth was noted. The starch had not dried out 
much and the whole of it was still bluish white, indicating that there 
had been no considerable diastasic action. The streak was very thin, 
very pale 3^ellow, did not hide the substratum, and had no well-defined 
margins. On the sixty-second day there was decidedly more growth, 
the whole surface being covered with a thin, distinctly 3'ellow, smooth, 
homogeneous, wet-shining layer. The body of the starch still pre- 
served its bluish white luster and retained its water well. The amount 
of growth in this tube after 62 days was not greater than that present 
in the other tube at the end of 5 days. In the tube which received 
the diastase there was, on the fifth day, a distinct but not very copious 
growth, covering about two-thirds of the slant surface. On the 
twelfth day there was an abundant bright j'ellow growth covering the 
whole surface and affording a striking contrast to the check tube. 
This contrast continued for some time, the difference in the 2 tubes 
on the fourteenth da}^ being shown in figs. 15 and 16 of the plate 
accompany ing bulletin 26 of this Division. The color was approxi- 
mately Ridgway's canary yellow (VI-12). On the twenty-seventh day 
the slime was still bright yellow, and the amount of growth was esti- 
mated at 200 times that in the check tube. On the thirty-ninth day 
there was still no brown stain. 

(2) After 8 days the other 1 tubes were reinoculated copiously over 
the whole surface with yellow slime taken from the culture just 
described. They were under the same conditions as to light and tem- 
perature, the greatest difference between these and the preceding 
being the enormous number of germs used in making the inoculation. 

Result. — The 2 check tubes behaved alike. On the fourth da}^ there 
was a trace of 3^ellow growth at the bottom of the slant, but it was 
feeble, and was visible on not more than one-fiftieth of the whole sur- 
face. At this time the tubes which received the diastase showed an 
abundant bright yellow growth over the whole surface, a growth several 
hundred times as abundant as that in the check tubes. On the sixteenth 
day, in the check tubes, there was only a feeble growth of 9 or 10 square 
millimeters. This growth was bright ^'Cllow, but it was not one one- 
hundredth as much as in the tubes which received the diastase. On the 
twent3^-seventh da3^, in the check tubes, the growth had doubled, but 
the substratum was hidden onl}' over a few square millimeters, and the 



61 

ratio of growth in the 2 sets of tubes was still about tlie same, viz, 
1 : 100. The starch was still bluish white. On the twenty-seventh day, 
in the tubes which received the diastase, the growth covered the whole 
surface of the slant (800 to 900 sq. mm.) with a smooth, homogeneous, 
wet-shining, canary yellow layer, which was abundant enough to hide 
the substratum. There was a trace of pink in the starch, but no brown 
stain. On the thirty -fifth day the starch jelly was removed from one 
of the check tubes. It was as firm and elastic as when first prepared. 
On breaking it into fragments and throwing it into boiling Soxhlet's 
solution (5 c. c. standard CuSO^ 5 H^O solution; 5 c. c. standard alkaline 
solution; 40 c. c. distilled water) and continuing the boiling 3 minutes, 
the fluid was as blue as at the beginning, and the only precipitate of 
copper oxide was an extremely slight one restricted to those fragments 
of the jelly which were immediately under the bacterial layer. Cer- 
tainly not more than one one-thousandth of the starch was converted. 

(3) The experiment just described was repeated 3 months later in 
the warmer weather of midsummer. A new stock of the medium 
was prepared and in this case each tube received 2 gr. of the dry 
potato starch and 8 c. c. of the nutrient mineral solution. Instead, 
however, of converting the starch with diastase, the carbon food was 
supplied by the addition of various sugars, alcohols, and gums. 
No mention will be made here of anything but the check tube 
and a tube of the same stock fortified by the addition of 500 mg. of 
a dextrine, which contained a substance reducing Soxhlet's solution 
but no amylodextrine and no substance reducing Barfoed's reagent. 
Both tubes were inoculated at the same time and in the same way; i.e., 
each with a large loop of yellow slime from a fructose-agar culture 
17 days old, but still in excellent condition owing to its having grown 
slowly on the start. The tubes were kept in a dark closet at room 
temperatures ranging from 25° to 32° C. (30° to 32° during the first 
5 days). Tubes of Ps. campestris and Ps. ■phaseoU were also inocu- 
lated at the same time and kept under the same conditions. 

Result. — In the check tube of Ps. hyaclnthi there was no visible 
growth during the first 18 hours. On the third day there was a very 
slight growth (barely visible), and the bluish white translucent appear- 
ance of the starch remained unchanged. In the tube which received 
the dextrine, growth was visible in 18 hours, ))ut it was still feeble on 
the third day; i. e., growth was retarded. On the third day, in the 
check tubes of Px. campeHtrk and T^s-. phaseoll, there was 20 times as 
much growth, and the starch jelly under the slime, to a depth of 2 
mm., was changed to a dead, opaque white. Returning to the hya- 
cinth germ, there was on the seventh day, in the check tube, a very 
thin, pale yellow streak or film down the middle of the slant. In the 
tube which received the dextrine the whole surface was covered by a 



62 

thin distinctly yellow layer; i. e., there was several times as much 
growth as in the check tube, but there was no visible diastasic action. 
The growth of P.s. phaseoU on the check was now at least 100 times as 
abundant as that of Ps. hyacmthi on the same medium. 

On the starch jelly with addition of the dextrin Ps. carn.pestris and 
Ps. phaseoli both made a good growth. On the seventh daj^ Ps. 
canvpestris covered the whole surface of the long slant to a depth of 1 
to 3 millimeters with a semifluid, smooth, wet-shining slime, and the 
diastasic action now involved nine-tenths of the starch. The conver- 
sion of the starch was clearly visible, proceeding slowh^ and uniformly 
from the surface of the slant inward. There was a distinct line of 
demarcation between the converted and unconverted starch. The 
latter was bluish white, opalescent, translucent, firm, elastic, insolu- 
ble; the former was dead white, opaque, soft, inelastic, and soluble in 
water on gentle shaking. This part gave no color reaction whatever 
on adding iodine water. On washing it all out the unchanged one- 
tenth in the bottom of the tube was seen to have presented the shape 
of the original slant, and on adding the iodine water it became bright 
blue. In the corresponding tube of Ps. phaseoli the growth at this 
time appeared to be equally as good, but only about two-thirds of the 
starch was converted. The diastasic action proceeded from the surface 
inward in the same regular manner, the line of demarcation between 
converted and unconverted starch was equally sharp, and the converted 
portion had all the peculiarities recorded for that acted on by Ps. 
catnpestris. A fragment of this soft white starch as big as two peas 
was stirred up in 5 c. c. of the very sensitive pale brown alcoholic 
iodine water, but no color reaction could be obtained. This changed 
starch included all of the outer 5 or 6 millimeters of the slant; on fill- 
ing the tube part full of water and shaking gently all of it dissolved 
readily, leaving in the bottom a translucent, bluish white, insoluble, 
miniature slants which immediately reacted bright blue on pouring in 
the same iodine water. These experiments show that the presence of 
albuminoids is not necessar}' for the production of the diastasic fer- 
ment and also that it is excreted b}' these two species in the presence 
of an abundance of readily assimilable food. 

On the twelfth da}', in the check tube of Ps. Kyacinthi^ the thin, 
pale yellow gi-owth had extended over most of the slant surface, but 
it was still not one-hundredth part as abundant as in the correspond- 
ing tube of Ps. phaseoli^ and there was no evidence of any dia- 
stasic action, whereas in the latter more than nineteen-twentieths of 
the starch had been digested. In the tube which received the dextrin, 
Ps. hyacinthl had made, on this date, a good, bright yellow but rather 
dry growth over the whole surface. On the thirtieth day, in this 
same medium, there was a plentiful, smooth, wet-shining, bright 3^el- 
low slime over the whole surface, i. e., growth enough to hide the sub- 



68 

stratum, but no brown stain, no decided smell, and no ocular evidence 
of any diastasic action. The germs were carefully scraped off and 
iodine water poured into the tube, whereupon there was an immediate 
and general blue reaction, showing that very little of the starch had 
been changed. This shows clearly that increased growth does not 
necessarily imply an}' increased secretion of the diastasic ferment. 
The check tube could not be compared owing to a contamination. 

(4) A few days later another check tube was inoculated and a similar 
feeble growth ensued. A tube containing 500 milligrams of dextrin, 
which was inoculated for comparison, gave a much better growth. On 
the third day the whole surface of the slant in this tube was covered 
bj" a thin, distinctly j^ellow, dr}^ layer, and there was no visible dia- 
stasic action. On the twelfth day the growth was smooth, Avet-shining, 
bright yellow, and about S times as abundant as in the check tube. 
There was also a decided diastasic action, involving the outer 5 milli- 
meters of the starch. This result contradicts the preceding experiment 
with dextrin and is probabl}^ attributable to the action of some unde- 
tected, intruding organism (see p. 64). 

Nutrient Starch Jelly No. 2. 

The nutrient solution used in preparing this medium differed from 
the preceding by addition of sodium sulphate; by a considerable reduc- 
tion of the magnesium sulphate and calcium chlorid; b}- a slight 
reduction of the sodium chlorid, sodium asparaginate, and ammonium 
lactate, and by a slight increase of the dipotassium phosphate (for 
exact composition see loco clt.). Each tube received exactly 10 c. c. 
of this solution and 2 grams of dry potato starch free from an}^ trace 
of sugar. For comparison a culture was laid at the same time on 
starch jelly No. 1, containing 2 grams of the same starch and 10 c. c. 
of the glycerin-free Uschinsky. The slant surface of each substratum 
was inoculated in the same way, carefully and very copiously, with 
bright yelloAv slime from a starch-jell}^ culture IT days old. The tubes 
were kept in a dark place at room temperatures ranging from 21° to 
31° C. (most of the time below 28°). 

Result. — On the fifth day there was a feeble, bright yellow growth, 
much alike in each tube, and no visible diastasic action. On the elev- 
enth day there was a thin, bright yellow growth over nearly the whole 
surface — i. e., a considerable increase of growth, but still no diastasic 
action. Both tubes were much alike, but there appeared to be slightly 
moi-(^ gi-owth in starch jelly No. 1. On the twenty-fourth day the 
growth in starch jelly No. 2 had increased but little. This growth 
was wet-shining and distinctly yellow, but so feeble that the substratum 
was not hidden; there was no brown stain in the substratum, and no 
visible dia.,tasic action. In starch icily No, 1 there was distinctly 
more growth, but no visible diastasic action. An intruding colony 



64 

(the product of a spore which passed through the sterilizing oven 
uninjured) had come to the surface, and I suspected that sugar liberated 
by this colony had diffused through the substratum and stimulated the 
growth of Ps. hyacinihi. On the thirty -fifth da}^ there was no increased 
growth and no visible diastasic action in jelly No. 2, but in jelly No. 1 
the bright 3^ellow growth was 3 or 4 times as abundant and was now 
clearly attributable to diffusion of sugar, or some other assimilable sub- 
stance, liberated by the intruding organism. There was no visible 
diastasic action except in the starch immediately around where this 
white colony had come to the surface. The effect of the growth of 
this intruder was most clear cut and interesting. 

For comparison with these two tubes a culture was laid at the same 
time on starch jelly No. 2 with addition of 50U milligrams of dextrin. 
The organism grew well on this substratum, making 4 to 6 times as 
much growth as in the check tubes. On the twenty-third day, when 
last examined, there was an excellent growth and had been for 3 weeks, 
but there was no visible diastasic action. 

J*s, jphaseoli was very pale and made a much less abundant growth 
on nutrient starch jelly No. 2 (made with the modified Uschinsky's 
solution minus the glycerin) than it did on potato, or than did Pi<. cmn- 
pestris. In Uschinsky's solution, on the contrary, it was yellower and 
grew rather better than Ps. campestris. 

Hyacinth Starch Jelly. 

This was made by adding 1 gram of dry sugar-free hyacinth starch, 
obtained from bulbs, to .5 c. c. portions of Uschinsky's solution. Three 
tubes were prepared, to one of which was added 500 milligrams of 
cane sugar. The tubes were steamed 2 hours on each of 3 consecutive 
days at 91° C, this low temperature being obtained by putting the 
tubes in the top of the steamer with the vents left open. The tubes 
were inoculated with Ps. hyacinth/ very copiously in the same manner 
soon after the third steaming from a starch jell}" culture 7 days old. 
They were kept together in a dark place at room temperatures ranging 
from 15° to 26° C. 

Result. — At the end of 48 hours (temperature, 21° to 22° C.) growth 
was visible in each tube. At the end of the fourth daj'^ the 2 check 
tubes were alike, the whole surface of the long slant being covered 
with a very thin, distinctly yellow growth. There was, however, no 
visible diastasic action, the organism behaving on hyacinth starch 
exactly as on potato starch. In the tube which received the cane 
sugar there was 4 or 5 times as much growth as in either of the check 
tubes. This growth was bright yellow and covered nearly the whole 
surface of the slant, but there was no visible diastasic action, the 
increased growth being due to the presence of the cane sugar. A lit- 
tle later this tube was accidentally broken.. The check tubes were 



65 

under observation for an additional 24 days, during which time a great 
change took place in one of them, the growth increasing tenfold. 
This increased growth of the organism was due to no diastasic action 
of its own, but to the diffusion of maltose or dextrin liberated from 
the starch by some buried, slow-growing, white, starch-converting col- 
onies, which originated from spores that found their way into the starch 
during its preparation and which passed through the steamings 
uninjured. 

The foregoing conclusion is also supported by the fact, already set 
forth, that Pa. hyachithi grows well on a variety of crude vegetable 
substances I'ich in sugar. That this feeble diastasic action partially 
accounts for the feeble parasitism admits of little doubt. Probably 
its feeble cytohydrolytic action and its strict aerobism are also restrain- 
ing influences. 

AEROBISM. 

As already noted, th(> l)uried colonies of Ps. hyacinthi in plate cul- 
tures grew slowly, and those deepest in the layer of agar or gelatin 
remained smallest. In the stal) cultures also the bacteria gradually 
faded out in the depths, making nuich the best growth near the surface. 
The additional results bearing on the inability of this germ to grow 
in the absence of free oxygen are thrown together in the following 

paragraphs. 

Fermentation Tubes. 

The form of tube used in my laboratory is that devised by Dr. Theo- 
bald Smith and made by E. Greiner, of New York.' This, by reason 
of its size and shape, the writer has found more satisfactory than sev- 
eral other sorts he has tried. 

First is a table, which sets forth the results obtained with fermen- 
tation tubes in 1897. The tubes were filled with distilled water con- 
taining 1 per cent of Witte's peptonum siccum and 1 per cent of the 
sugfar or other substance to be tested. 



^ The fermentation tube, with special reference to anaerobiosis and gas production 
among bacteria. The Wilder Quarter Century Book, Ithaca, N. Y., 1893, p. 187. 

21T88— No. 28—01 5 



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68 

Each of these tubes was inoculated February 12 with one loop from 
a beef broth culture made Februar}^ 5. This culture was well clouded 
and becoming moderately turbid from the presence of numerous 
small zoogloeae. It also contained a moderate amount of yellow 
precipitate. The tubes were very clear when inoculated, and perfecth^ 
sterile, the third steaming havnng taken place some weeks previous. 
The fluid in each tube was feebly alkaline, to litmus when inoculated. 
The cultures were kept at living-room temperatures (20^ to 23^ C). 
February 19 the cultures were first tested with litmus (the best neutral 
litmus paper procurable). The fluid in each was plainh' alkaline 
(much more so than on the start). March 1 the fluids were again tested. 
All were alkaline to neutral litmus paper. ]\larch 12 the cultures were 
again tested. Each was plainly alkaline, although not strongly so. 
The blue color faded out when the paper dried. If anj- acid was 
formed it was masked by the alkali originally present in the tubes 
and by that produced during the growth of the organism. 

The above results were obtained in 1897. In 1899 additional fer- 
mentation-tube experiments were instituted with the following results: 

(1) One of the fluids used was a 1:2 nonpeptonized beef bouillon 
(stock 382) rendered neutral to phenolphthalein with sodium hydrate 
and deprived of its muscle sugar by growing Bac'iUus coll in it over 
night. It was then cleared by passing it through a Chamberland 
filter. The following substances were tested in this bouillon: Grape 
sugar, cane sugar, and galactose (3 tubes of each). Each tube con- 
tained 5 per cent of the sugar to be tested except those with the 
grape sugar which contained 2.8 per cent. The inoculations were 
made February 2 and the experiment was closed March 4. The tubes 
of grape sugar and cane sugar were all well clouded (in the bowl and 
outer two-thirds of the U) on the fifth day, with exception of one of 
the grape-sugar tubes which was then only ver}" feebly clouded, but 
was well clouded 2 da3's later. In each case the closed end of the 
tube and the inner one-third of the U remained clear until the end of 
the experiment. The reaction to litmus was watched carefully. The 
fluid in the bowl of each of the tubes was plainly alkaline to litmus 
paper (wet or dried) on the ninth, fifteenth, and twenty-third days. 
On the thirtieth da}' in each tube, whethe^i* of grape sugar or cane 
sugar, the litmus reaction was distinctly different. The tests were 
made with two freshly prepared sensitive litmus papers, the one 
purplish red. the other pale lavender blue. The fluids how blued the 
purplish red paper slightly and at the same time reddened the bluish 
paper. The contrast in each case to inoculated check tubes of the 
plain bouillon (which were now intensely alkaline and blued both 
papers) was striking. The only conclusion I could come to was that a 
definite but small amount of acid had been formed slowly from the 
grape and the cane sugar. In comparison with plain bouillon these 



69 

sugar bouillons stimulated growth. No gas was formed. The growth 
in each was typical for Ps. hyacinthi. 

In 2 of the 3 tubes of galactose Ps. hyacinthi refused to grow, and in 
the third clouding did not appear until after the seventh day. On the 
ninth da}^ the fluid in the bowl and outer two-thirds of the U was 
feebly clouded. After a time there was an abundant 3'ellow growth 
on the operr end of the tuVje, but the closed end remained clear 
throughout the experiment. The fluid, as we have seen, was neutral 
to phenolphthalein (strongly alkaline to litmus) on the start. It was 
still strongly alkaline to litmus on the ninth day; on the fifteenth day 
it was moderatel}^ alkaline. On the twenty-third da}^ it was neutral 
to litmus or nearh^ so, but so was an uninoculated tube. On the 
thirtieth day the fluid was distinctly acid, even to the purplish red 
paper. No gas was produced. The cloudy fluid was now pipetted 
from the open end of the bulb into a clean test tube and reduced b}'^ 
boiling to one-third its original volume. Moistened litmus paper was 
reddened in the vapors which first came oft' (CO.j::). Afterwards there 
was no reddening of the litmus paper in the steam and the concentrated 
fluid was more acid than before. 

The fact that the organism failed to grow in two of the tubes and 
was retarded in the third was attributed to the effect of a soluble 
brown substance which appeared in the tubes as a result of the 3 
steamings which followed the addition of the galactose. 

(2) Absolute ethyl alcohol was also pipetted into 4 tubes of the same 
stock. Two of the tubes received 2^ per cent and two 5 per cent of 
this alcohol. Each tube was then inoculated with two 3 mm. loops 
from fluid cultures 13 days old (tubes 1 and 2, January 20, 1899). 
This experiment was suggested by the results obtained with Sharp 
and Dohme's litmus solution in milk. In one of the 5 per cent alco- 
hols the organism failed to grow. In the other 3 tubes clouding 
occurred on the fifth to the seventh day; i. e., growth was retarded very 
decidedly. The tubes never became heavily clouded; growth ceased 
early and the closed end remained clear (30 days). The fluid was 
plainly alkaline to litmus at the beginning and on the ninth and the 
fifteenth days. On the latter date the appearance of the cultures was 
that of simple toleration of the alcohol rather than of any use of it for 
growth. The alkalinity in one of the 2^ per cent tubes on the fifteenth 
day was rather feeble; i. e., much less than in an uninoculated tube or 
than in inoculated tubes of the simple bouillon. On the twenty-third 
day the fluid had settled clear and was feebly acid to litmus. On the 
thirtieth day the fluid (in each tube) was clear and was distinctly acid 
to both the litnuis papers. No gas had formed. The precipitate was 
distinctly yellow but scanty; i. e., there was only about one-twentieth 
to one-fiftieth as nuich as in the tu])es of simple bouillon and about 
one one-hundredth as much as in the tubes of grape sugar and cane 



70 

sugar. The least growth was in the 5 per cent alcohol. Evidently 
the acid which was formed inhibited growth, although it did not 
immediately kill all of the organisms. This was determined by mak- 
ing 6 cultures from the 5 per cent alcohol on the twenty-third day (2 
carrot, 2 potato, and 2 coconut cultures— 1 loop for each). The 
oro-anism erew in all the.se tubes, but its development was slow. It 
was not visible in any of them on the fourth day. The yellow growth 
appeared in 5 of these tubes on the sixth day and in the sixth tube a 
day or two later. A fact which shows the remarkably slow diffusion 
of the acid is that the fluid in the closed end of the tubes (2i per cent 
alcohol) remained alkaline while that in the open end became acid. 
On tho thirtieth day, in 1 tube, the fluid in the bowl was " distinctly 
acid to the blue paper and also to the pale red paper;" in the other it 
was "'strongly acid to both red and blue papers." Nevertheless, 
when the contents of these 2 tubes was poured out into a clean test 
tube and thoroughly mixed it was no longer acid to either paper, but 
had become slightly alkaline; i. e., not enough acid was produced in' 
the open end of the tube to neutralize the sodium hydrate in the 25 
c. c. of fluid (25 c. c. of ^ NaOH per liter). This fluid was then reduced 
one-half by boiling, but no acid vapors appeared in the steam. 

(3) The experiments with glycerol and maltose were repeated to see 
whether the faint clouding which finally appeared in the closed end, 
in the experiments of 1897, should be attributed to facultative anae- 
robism or only to some accident. The stock used was a 1:2 slightly 
alkaline non-peptonized sugar-free beef bouillon (No. 450).^ 

To this was added 2 per cent of Schering's twice distilled c. p. 
glycerin in the one case and 2 per cent of Merck's c. p. maltose in 
the other. The experiments were carried through in duplicate. Hav- 
ing been on the shelf 15 days since the last sterilization, the tubes 
were resteamed for 20 minutes but no air bubbles appeared. Each 
tube was then inoculated with one 3 mm. loop from a cloudy broth 
culture 3 days old. The observations were continued 23 days. 

Beaiilt. — The tubes of glycerin bouillon clouded in the bowl and outer 
three-fourths of the U on the second day, but remained entirely clear in 
the closed end during the whole time. The glycerin gave no increased 
clouding, i. e., not more than the simple bouillon. The line of demar- 
cation in the U remained sharp. The fluid was slightly alkaline to 
litmus when inoculated and was neutral to feebly alkaline at the close 
of the experiment. 

The maltose bouillon was feebly clouded in the bowl and outer three- 
fourths of the U on the second day. The line of demarcation in the 
U was sharp on the third day. On the seventh day the bowl and outer 
three-fourths of the U were uniformly and well clouded. This cloud- 
ing was decidedly more than in the corresponding tubes of gh^cerin 

' Freed from muscle sugar by B. coli and clarified with white of egg. 



71 

bo,uillon. The closed end and inner one-fourth of the U were still 
perfectl}^ clear. On the twelfth day the line of demarcation in the U 
was less distinct and there was a faint haze in the lower part of the 
closed end (3 cm.). On the twenty-third day the faint haze had involved 
the whole of the closed end, but had not become any denser, i. e., the 
clouding- in the closed end was not one one-hundredth part that in the 
open end. The fluid was feebly alkaline at the beginning of the exper- 
iment and was decidedly acid (to neutral litnuis paper) at the close, i. e., 
the reaction was in marked contrast to that of the glycerin bouillon. 
Both tubes of the maltose bouillon behaved alike. They had been pro- 
tected from jarring and inequalities of temperature, and steaming for 
50 minutes at the close of the experiment did not clause the formation 
of any air bubble in the closed end. This very feeble clouding in the 
closed end after the second week would seem therefore to be due either 
to some contaminating substance in the maltose or else to that sub- 
stance itself. 

(4) The nitrate bouillon (stock 474) was also tested in fermentation 
tub^s. Two tubes were inoculated from solid cultures 7 days old. Both 
clouded on the second day, both remained entirely clear in the closed 
end and inner one-fourth of the U until after the eighth day. On the 
fourteenth day both were feebly clouded in the whole of the closed 
end. No gas was formed and the fluid remained strongl}^ alkaline. 

On steaming these two tubes a bubble appeared in the closed end of 
each, and the feeble clouding was consequently attributed to growth 
stimulated by the presence of air absorbed from the open end. 

The closed end of fermentation tubes fllled with the following sub- 
stances and inoculated with Ps. campestrk remained entirel}'- free from 
clouding: Potato broth; cabbage broth; cauliflower broth; peptone 
water with grape sugar, fruit sugar, cane sugar, milk sugar, galactose, 
maltose, dextrin, and glycerin. The open end clouded. 

Dibasic calcium phosphate added in 5, 10, 20, and 30 milligram 
doses to test tubes holding 10, 15, and 20 c. c. of a peptone water con- 
taining grape sugar and glycerin, doubled the growth of Ps. cainpestris. 
Other species were not tried. This fluid was then tested in fermen- 
tation tubes. The calcium salt stiumlated growth in the open end, but 
the closed end remained clear for three weeks. Afterwards there was 
clouding. This stock consisted of 200 c. c. of Altered Potomac water, 
2 grams of Merck's c. p. anhydrous grape sugar, 4 c. c. of Schering's 
glycerin, and 2 grams of Witte's peptonum siccum; the whole dried 
out one-half by long standing and diluted with three times its hulk of 
di.stilled water before flUing into the tubes and adding the phosphate. 

Dibasic sodium phosphate used in the same stock also favored the 
growth of Ps. cainpestris. 

From the above account it will be seen that in various ways the 
behavior of Ps. hyaclntld in fermentiition tubes closely resembles that 



72 

of Ps. camjpestris. Ps. phaseoli has not been tested so extensivelj^ but 
reacts in the same way, so far as tried, i. e. , it produces no gas and is 
strongl}^ aerobic. Ps. stewarti produces no gas and appears to be 
strictly aerobic, but is able to get along w^th a relatively' small amount 
of air. A small amount of some non-volatile acid or acids appear to be 
produced by it from grape sugar, cane sugar, galactose, and mannitol, 
but not from glycerol. 

Growth in Nitrogen. 

The tests were made in U tubes holding 250 c. c. and open at each end. 
Two verv short cotton-plugged test tubes containing the freshly steamed 
culture medium were inoculated with Ps. hyacinthi and thrust, one 
above the other, into one arm of the U tube, which was then tightly 
closed with a soft rubber stopper and plunged, for greater security, 
into a beaker of glycerin. Into the other arm was thrust quickly a 
longer test tube filled with a mixture of pyi'ogallic acid, caustic pot- 
ash, and water. This end of the tube was then plunged into a beaker 
of mercury and held down until the absorption of oxj^gen equalized 
the pressure and enabled it to remain down of its own weight — a period 
of some hours. The following experiments were tried in these tubes: 

(1) The first experiment was with cylinders of freshly prepared 
coconut, a medium on which this organism was known to grow with- 
out retardation. Four tubes were inoculated. Two received each one 
loop of yellow slime from a solid culture T days old, which slime 
was rubbed carefully over the whole surface. Two received each two 
loops of fluid from the bottom of a potato (?) culture 7 da3''s old, 
after shaking. One tube of each set was held as a check. The other 
2 tubes were put into one arm of a U tube the other end of which 
received a tube holding 2 grams of pyrogallic acid and 25 c. c. of 13 
per cent caustic potash water. The room temperature during the 
experiment ranged from 17° to 26° C. The oxygen was gradually 
absorbed and the tubes remained exposed to the nitrogen for 15 days. 

Result. — In 48 hours from the time of inoculation the check tubes 
showed a good growth. On the eighth day the check cylinders were 
covered with an abundant, smooth, wet-shining, canary-yellow growth. 
In each tube there was at least 6 sq. cm. of this growth. During the 
same time, in the tubes exposed to the nitrogen, there was no visible 
growth. 

On the fifteenth day the mercury seal was broken and the tubes 
were taken out and examined more criticall}". One tube showed no 
growth whatever and the other an extremely slight pale-3'ellow 
growth, best seen with a hand lens, and aggregating not over one- 
fourth of 1 sq. mm., 1. e., not more than might have grown around one 
of the coarser fragments of the inserted slime before all of the oxygen 
was absorbed. At this time the contrast with the checks was very 



73 

striking. The tiny bacterial mass referred to contained no chains, no 
spores, and no invohition forms. It consisted of slender rods, single 
or in pairs and very short, as if not now dividing. Exposure of these 
rods for 10 minutes to a temperature of 74'^ C. falling to 60° C. killed 
all of them. 

The unexpected feature of this experiment was that after removal 
to the air growth did not appear in these tubes as soon as it did in the 
check tubes; in other words, the sojourn in the nitrogen seemed to have 
exerted an injurious influence. One of the tubes (that inoculated from 
the solid culture) showed a slight growth at the end of the third day, 
the other one not until the fifth day. Five days after removal from 
the nitrogen the bacteria in one tube had made al)out as much growth 
as the check tubes made in 48 to 60 hours. In the other tube they 
had made a thin pale yellow growth covering not more than 1 sq. 
cm. — i. e., not more than one-tenth as much growth as the check tube 
made in the same time. In the course of another 3 or 4 days the 
bacteria in both tubes made an abundant bright yellow growth. 

Ps. Stewart i tested at the same time behaved in the same way. At 
the end of 15 days, when the seal was broken, there was no 3^ellow 
precipitate or visible slime, colored or colorless, in either tube. The 
two check tubes showed a distinct growth in 48 hours, and continued 
to grow in a typical wa}". On the contrary, there was no visible 
grow^th in either tube on the fourth day after removal from the nitro- 
gen. On the fifth day in the tube which was inoculated from a solid 
culture there was a slight yellow growth over a few square millimeters. 
In the other tube no growth was visiVjle until the eighth day after the 
removal, and then it was scanty. This cylinder stood in one-half c.c. 
water and was still moist. Two days later there was a good growth 
on both cylinders. 

(2) The stock in the second experiment with Ps. hyaclnthi consisted 
of 6 tubes of white turnip. Each of 3 was inoculated with one loop 
of a ver}' cloudy beef-broth culture 6 days old. Each of the other 
3 was inoculated with one loop of very cloud}' fluid from the bottom 
of a young bright yellow and very vigorous culture on coconut 
after prolonged shaking.. Two of the tubes were held as checks. The 
other 4 were put into 2 U tubes in the way already described. In 
each case a test tube (capacity 25 c. c.) packed nearly full of pN'rogallic 
acid was then filled with 6i per cent caustic potash water and imme- 
diately thrust into the other arm of the tube, which was then plunged 
into the mercury. By the end of 24 hours, and prol)abl3^ sooner, the 
absorption of the oxygen was complete — i. e., there was no farther 
rise of the mercury or change in the color of the pyrogallic acid. 

Penult. — In one of the check tubes growth was plainly visible on the 
third day, in the other not. On the sixth day in one check tube there 
was an abundant smooth, wet-shining growth over the whole cylinder 



74 

out of the water; the fluid was also heavily clouded, and there was 
considerable pale yellow precipitate. In the other check tube growth 
was not so abundant, but about 3^ sq. cm. of the slant surface was 
covered with a smooth, wet-shining, pale j^ellow growth. 

The tubes were removed from the nitrogen on the fifteenth day. In 
none of the 4 had there been any growth whatever, although there 
was an abundance of moisture in each. Moreover, in none of them 
did any growth subsequently appear (17 days). 

The pyrogallic acid used in this instance was a fresh supply and had 
a peculiar penetrating smell. Whether the failure of these cultures to 
grow after removal to the air is to be ascribed to the nitrogen or to 
some substance emanating from the pyrogallic acid must be left an 
open question. 

Pa. cainpestrls and Ps. stevxirtl were tested at the same time with 
identical results. The check tubes grew promptly. The others (2 of 
Ps. ca/mpestris and 4 of Ps. stewarti) made no growth whatever, either 
while in the nitrogen (15 days) or after being taken out (17 days). 
The temperature during this experiment ranged from 20° to 25° C. 

(3) The third experiment did not fully accomplish what was intended, 
but is perhaps just as instructive. Each U tube received a tube con- 
laining 10 grams of an old stock of pyrogallic acid, not previously 
used, and 20 c. c. of 5 per cent caustic potash water. It browned 
slowly, and at the end of 48 hours a considerable part of the oxygen 
remained unabsorbed (perhaps one-third), and meanwhile the bacteria 
had begun to grow. The cultures were on coconut. Each tube was 
ino(;ulated with two 3 mm. loops of Ps. liyacintld from a cloud}^ beef- 
broth culture 5 days old. 

Result. — The check tube grew promptly. During the first 46 hours 
the bacteria in the two tubes in the nitrogen (+ some oxygen) made 
al)out one-half as much growth as in the check tube. The column of 
mercury was now 40 mm. high. There was some additional growth in 
these tubes on the third day, but it was paler yellow than in the check 
tube. At the beginning of the fifth day the mercury stood at 58 mm. 
and the oxygen was proljably all absorbed. From this time on there 
was no increase in growth. On the fifteenth day the seal was broken 
and the tubes removed for a more careful examination. The pale yel- 
low growth in each tu})e was not more than one-twentieth as much as 
in the check tube. 

The results were much the same in another U tube. At the end of 
the second dav the mercurv stood at 35 mm. At the besrinnino- of the 
fifth da}' it had reached 59 nun. During this very gradual absorption 
of the oxygen there was some growth, but it was less than in the check 
tube (not over one-fifth as much), and it ceased after this date. The 
color of the slime in the check tube at this time was canar}^ yellow. 



75 

The color of the slime in the tubes from the nitrogen was paler, i. e., 
between primrose and Naples yellow. This U tube was also opened on 
the fifteenth day, at which time the g-rowth was still pale 3'ellow and 
not over one-thirtieth as abundant as in the check tube. 

In 8 days from the time these 4 tubes were removed from the nitro- 
gen there was an abundant, smooth, wet-shining, bright yellow growth 
in each tube. This new growth began to ])e visible at the end of the 
second day. That a considerable portion of the germs were injured 
by exposure in the U tube was, however, shown by the fact that scrap- 
ings taken from the rather dry bacterial laver in each one of these 
tubes when they were tirst opened and put into as many tubes of beef 
broth failed to cloud them in 8 days. 

I^s. canipestris and Ps. stewarti were tested at the same time. Ps. 
cam,pestris was grown on cylinders of flat white turnip in distilled 
water and P^. stewaHi on similar cylinders of sugar beet, i. e., each 
one on a medium specially adapted to its growth. In the check tubes 
growth was prompt and abundant. 

In the U tube containing Ps. campestris the mercur}' had risen only 
30 mm. in 46 hours, and there was nearly or quite as much growth 
in these tubes as a\ the check. On the beginning of the fourth day 
the mercury stood at 50 mm., and the growth was comparatively 
feeble, i. e., not one-twentieth as much, as in the check. On the fif- 
teenth day when the seal was broken the slime had dried away and 
there was no apparent growth in either tube. Eight days later each 
cylinder was covered with a copious pale yellow, smooth, wet-shining 
slime which also filled the fluid. This increased growth began to be 
visible the second day. A second U tube gave identical results. 

In the U tube containing Ps. stewarti the mercury had risen only 
15 mm. in 46 hours and there was about as umch growth as in the 
check. At the beginning of the fourth daj' the mercury stood at 50 
mm., and the growth was now not one-fifth as much as in the check 
tube. At the beginning of the fifth day the mercury stood at 55 mm., 
i. e., nearly all of the oxygen was absorbed and the growth was not 
one-tenth as much as in the check tube. At this time the color of the 
growth in the check tube was between buff yellow and deep chrome, 
that in the tubes in the nitrogen was ''pale yellow.'" On the fifteenth 
day when the seal was broken there was not in either of these tu))es 
over one-thirtieth as nuich growth as in the check, and it was paler 
y.'llow. In the fluid in the bottom of the check there was also a 
copious bufi'-yellow precipitate, but there was none in either of the 
tubes which had been in the nitrogen. Here, again, something scem-s 
to have done injury to the organisms, for after })reakiMg the selil 
and exposing them to the air there was little increase in growth (8 
days). The check was deep buft" yellow. In the tubes which had 



76 

been in the nitrogen there was no buff yellow, but only a thin whitish 
growth. These 3 tubes were each inoculated in the same way, i. e., 
with 2-3 mm. loops from a beef-broth culture 5 daj'^s old. 

Growth in Vacuo. 

(1) The hrst test was in a partial >'acuum with the remnant of the 
oxygen absorbed. Under the bell jar with the cultures was a beaker 
containing 6 grams of pyrogallic acid. In this beaker was a U tube, 
the short arm open, the long arm closed, and containing 30 c. c. of 13 
per cent caustic potash water, with a small bubble of air at the top. 
The size of this bubble was so regulated that its expansion would 
begin to force over the potash water into the p3^rogallic acid when 
four-fifths of the air was exhausted. The exhaustion was continued 
until the mercury in the cistern barometer stood at 2i inches. The 
stopcock was then turned and the apparatus separated from the pump, 
well sealed, and put away in the dark. The temperature during the 
experiment was 20° to 26^' C. 

Eight test-tube cultures of Ps. hyacinthi were subjected to this 
experiment. Four were on coconut (stock 395), each being inoculated 
with one loop of 3'ellow slime from tube 27, February 2. Four 
were on potato (stock 385), each being inoculated with two loops of 
fluid from the bottom of tube 29, February 2, after long shak- 
ing. Two tubes of each set were placed under the bell jar and the 
other 4 tubes were held as checks. The experiment was begun on 
February 9 and the seal of the jar was broken February 18, at which 
time the vacuum continued as perfect as when hrst made. 

Result. — The 4 check tubes each showed a distinct vellow growth at 
the end of 48 hours, and this growth continued in a typical manner. 
The 4 tubes in the vacuum showed no growth whatever at the end of 
the ninth day, when the vacuum was broken. Twenty-four hours 
later there was no visible growth in any of these tubes. At the end 
of 48 hours the 2 potato cultures showed no growth; the coconut 
cultures showed a slight yellow growth on the inoculated face. At 
the end of the third day the coconut cultures showed two or three 
times as nmch growth as at the end of 48 hours, but the growth was 
still thin and did not cover all of the cjdinder, i, e., was not more 
abundant than the growth in the check tubes at the end of the third 
day. One of the potato cultures now showed a feeble yellow growth 
(less than the check tube showed at the end of the second day), and 
there was still no visible growth or graying of the substratum in the 
other tube. Six days after removal from the vacuum there was a 
moderately abundant bright canarj" yellow slime covering all that part 
of the coconut cylinders which projected out of the water. One of 
the potato cultures now contained about as much growth as the check 
tube, while the other also showed some growth (4 sq, cm.). In other 



77 

words, there was no growth in the oxygen- free vacuum; and 9 days' 
exposure to it while not killing all of the organisms probably killed 
many of them, since subsequent growth in the air was distinctly 
retarded. 

Cultures of J-*s. stewarti and of Bacillus amylovoms were also 
exposed to this vacuum. Bacillus amylovorus was inoculated on ordi- 
nary slant beef extract peptone agar. On this substratum, which 
probably contained a little muscle sugar, it made a slight but distinct 
growth. The check tube developed promptly, and made a good white 
growth the whole length of the streak. The growth in vacuo was 
about one-tenth to one-fifteenth as much as in the air. The 4 check 
tubes of Ps. stewarti (2 coconut, 2 potato) developed a distinct buff 
yellow -growth within 48 hours. The 4 tubes in vacuo made no growth 
whatever during the 9 days' exposure, and after removal to the air 
growth in each one was even more distinctly retarded than in case of 
Ps. hyacinthi. 

(2) The second test was made in the same manner as the first, except 
that the vacuum was not so complete and the remnant of oxygen was 
not removed. The experiment was begun March 8, and the seal was 
broken March 20. The mercury in the cistern barometer was down to 
3 inches when the jar was sealed, and the vacuum kept quite well. 
The temperature during the experiment was 16° to 25'-' C. (mostly 20° 
to 22° C). 

Four organisms were tried in this jar, Ps. liyacinthi., Ps. campestris., 
Ps. stewarti^ and Bacilkis carotovorus. The media used were carrot 
(stock 402), alkaline beef broth (stock 382), coconut (stock 412), and 
potato (stock 406). All of the check tubes but one made a "feeble" 
to "good" growth within 48 hours, and all showed a "good growth" 
at the end of the third day except one tube of Ps. hyacinthi on potato, 
which lagged and was doubtful, but which 2 days later showed the 
typical yellow growth over about 4 sq. cm. The tubes in the vacuum 
were distinctly different. On the fifth day Ps. hyacinthi showed some 
growth on coconut and potato, but it was not as yellow as in the air. 
The same was true of Ps. campestris and Ps. steivarti. Each showed 
some growth, and neither was as yellow as in the checks. On the 
eighth day the mercury stood at 3f inches, and none of the potato 
cylinders were grayed. The condition on the twelfth day (March 20), 
when the seal was broken, and on subsequent days, was as follows: 

Ps. hyacinthi: 

(a) Carrot. — March 20, no visible growth (there was no check upon this tube); 
March 23, no growth; March .31, no growth; April 5, a smooth, wet-shining, trans- 
lucent growth now covers the whole exposed surface of the carrot, and the precipi- 
tate is yellow; April 17, slime and fluid distinctly acid. 

(b) Beef broth. — March 20, fluid clear, precipitate very slight (2 mm. broad), 
colorless; no rim, no pellicle, iio zoogloeee; March 23, feebly clouded; March 31, well 
clouded. 



78 

(c) Coconut. — March 20, a very thin pale-yellowish growth, not one one-hundredth 
as much growth as in the check tube; the difference in color was not due to unlike 
volumes; bulk for bulk on white paper the slime from the check tube was yellower 
than that from the tube exposed to the vacuum. March 23, a thin growth covers 5 
to 6 sq. cm.; it is yellow, but rather pale for this substratum. March 31, a bright- 
yellow growth now covers most of the aerial portions of the cylinder. 

(d) Potato. — March 20, a distinct but feeble pale-yellow growth; about one-tenth 
as much growth as in the check tube; the potato has not grayed; bulk for bulk 
on white paper the slime from the check tube is yellower; compared as a M'hole the 
culture in the check tube was a canary yellow; that from the vacuum was primrose 
yellow. March 23, a thin growth covers 2 to 3 sq. cm.; it is yellow, but seems 
unusually pale. 

Ps. camj)estri.^: 

(a) Carrot. — ^larch 20, a very feeble growth; no check tube. March 23, a feeble, 
wet growth which does not mask the color of the carrot. March 31, a feeble growth; 
substratum not hidden. April 17, slime and fluid distinctly acid. 

(b) Beef broth. — March 20, clear; a very slight white precipitate closely resembling 
that of Ps. hyacinthi; not over one-twentieth as much precipitate as in the corre- 
sponding tube of Ps. s^tewarti. March 23, feebly clouded; March 31, well clouded. 

(c) Coconut. — March 20, a thin, pale-yellow growth over the whole aerial part of 
the cylinder; about one-fiftieth as much growth as in the check tube, and paler yel- 
low; the difference in color was also apparent when equal volumes of the slime 
were placed side by side on white paper. March 23, 8 to 9 sq. cm. of rather pale- 
yellow slime. March 31, a distinctly yellow growth over the whole exposed surface. 

(d) Potato. — March 20, the fluid is moderately cloudy and a thin, very pale-yellow 
growth covers the whole aerial part of the potato; there is no precipitate, no gray- 
ing of the potato, no thickening of the fluid or color in it; the check culture is 
much yellower and contains fully 100 times as much growth; the check tube is wax 
yellow; the other culture is as pale as primrose yellow; side by side on white paper 
in equal quantities the slime of the check tube was yellower. March 23, the entire 
aerial part of the potato is covered with a yellow slime which also begins to fill the 
water; it is still rather pale but begins to recover its color and vigor. March 31, a 
copious typical growth. 

Ps. stevarti: 

(a) Carrot. — March 20, only the slightest trace of growth; no check tube. March 
23, a slight growth, scarcely visible. March 31, fluid v/ell clouded; out of the water 
there is a thin slime which does not hide the carrot. April 17, slime and fluid, dis- 
tinctly alkaline. 

(b) Beef broth. — March 20^ fluid very feebly clouded; a pale-yellow precipitate, 
6 mm. in breadth, i. e., more than in the corresponding tubes of Ps. hyacinthi and Ps. 
campestris; check tube twice as cloudy and with double the precipitate, which is 
yellower; this organism seems to be able to get along with less oxygen than Ps. 
hyacinthi or P.s. campestris. March 23, fluid feebly clouded; cloudier than when 
taken out. March 31, well clouded. 

(c) Coconut. — March 20, a very thin, very pale-yellow growth; the check tube 
contains several times as much growth and it is yellower; the one is buft yellow, 
the other is cream (Ridgway); removed from the tube and examined bulk for 
bulk and side by side on white paper, the slime from the exposed tube was also dis- 
tinctly paler. March 23, a very thin, buff-yellow growth covers 4 to 5 sq. cm; it is 
paler than usual. March 31, there is now a thin, buff-yellow layer over the whole 
expo.sed surface. 

(d) Potato. — March 20, a pale buff-yellow growth about one-third to one-half aa 
abundant as in the check tube; potato not grayed, color only a little paler than 



79 

that in check tube. March 23, a very thin, pale buff-yellow growth covers 4 to 5 
sq. cm; the slime is very pale yellow for the amount of growth; the potato in the 
air begins to gray. March 31, growth feeble. 

Growth in Hydrogen. 

Two tests were made in hydrogen. The gas was prepared by the 
action of zinc on c. p. sulphuric acid dissolved in distilled water (acid 1 
part, water 9 parts). It Avas produced in quantity in a Kipp generator 
and was freed from impurities by passing it through strong solutions 
of argentic nitrate, potassium permanganate, and sodium bA'drate. It 
was finally allowed to bubble through a jar of distilled water and then 
passed into the culture chamber. This zinc was certified to be free 
from arsenic and subsequent tests did not reveal an}^ of this substance. 
To facilitate the removal of air, the gaseous contents of the well-luted 
bell jar was pumped out before allowing the hydrogen to enter. The 
jar was then repeatedly pumped out and refilled with the hydrogen, so 
that only a trace of oxygen could have remained. During the prelimi- 
nary trial exhaustions, leaks were of course discovered in various places 
and were waxed or screwed tight. At the beginning of each experi- 
ment everything was gas tight and remained so until its close (16 days). 
The exposures were in a large Novy jar. At the close of each experi- 
ment the tightness of the seal was demonstrated by the fact that when 
the -i clamp screws were loosened hydrogen passed out through the 
broad vaselined rubber joint (with a slight sound) in hundreds of tiny 
branching whitish rivulets and then air began to pass into the jar in 
the same curious way. 

(1) The first experiment Avas begun June l-i and closed June 30. 
The temperature during this period was the ordinary room tempera- 
ture of Washington (usually 25^ to 30^ C. in June). The inocula- 
tions were all into test tubes, using in case of each tube and of each 
organism one 2-mm. loop of cloudy beef broth 3 days old. The cul- 
ture media tested were potato (stock 519), +15 beef broth (stock 473a), 
and +15 nutrient slant agar (stock 516), i. e., media well adapted to 
these organisms. Various bacteria were tested. The observations 
on opening the jar June 30 (sixteenth day) and on subsequent days 
are given Ijelow: 

Ps. hyacinth i: 

(a) Potato. — June 30, no growth. July 2, no growth; plenty of water in the tube. 
July 5 (end of fifth day), doubtful; there seems to be feeble clouding and a slight 
growth on the potato out of the water. July 9, distinct feeble, pale-yellow growth; 
potato grayed; fluid feebly browned. July 16, a thin, yellow, typical growth covers 
a portion only of the exposed potato; there is also a small amount of yellow pre- 
cipitate; fluid abundant; a marked retardation of growth. 

(b) Beef broth. — June 30, clear; no growth. July 2, clear. July 5, no growth. 
July 9, not cloudy; July 16, clear; no grf)wth. 

(c) Agar. — June 30, no growth. July 2, no growth. July 5, no growth. July 9, 



80 

no growth. July 16, no growth; the agar is still quite moist, i. e., it has dried out 
only a little; this tube and the two preceding were inoculated from the same 
culture, tube 4, June 11 (stock 473a) , which was well clouded. 
Ps. cavipestris: 
{a) Potato. — June 30, no growth. July 2, no growth. July 5, no growth. July 9, 
no growth. July 16, no growth; plenty of water in the bottom of the tube and the 
aerial part of the potato moist; this tube and the two following were inoculated 
June 14 with a large 2-mm. loop from tube 13, June 11 (a beef-broth culture inocu- 
lated with a 2-mm. loop of yellow slime from a potato culture 36 days old); tube 
13, June 11, clouded in 24 hours, and was well clouded in 48 hours. 

(b) Beef broth. — June 30, clear; no trace of growth. July 2, clear. July 5, lost by 
accident. 

(c) Agar. — June 30, no growth. July 2, no growth. July 5, no growth. July 
16, no growth; failure is not to be accounted for l)y any drying out of the agar. 

Ps. stevarti : 

(a) Potato. — June 30, no growth. July 2, no growth; plenty of water in the tube. 
July 5, no visible growth. July 9, potato grayed, a very feeble buff-yellow growth, 
not over one-fiftieth as much as in the corresponding tube of Ps. hyacinthi. July 17, 
a feeble buff-yellow growth in the air; potato quite gray; fluid feebly browned; 
very little precipitate; a marked retardation of growth; this culture and the two 
following were inoculated from tube 22, June 11 (stock 473a), a well-clouded culture. 

(b) Beef broth. — June 30, clear; no growth, or a very slight one which has settled; 
the nature of the slight precipitate is doubtful; it was not examined microscop- 
ically; it is possible that a trace of oxygen was left in the medium, and this organism 
seems to require less 0. for its growth than Ps. hyacinthi or Ps. campestris. July 2, 
fluid feebly clouded; no rim or pellicle, but many small zoogloese. July 5, well 
clouded. July 9, well clouded; no pellicle or rim. July 16, moderately cloudy, no 
rim or pellicle, but numerous small zoogloese and a moderate amount of yellow pre- 
cipitate; no decided retardation of growth in the air. 

(c) Agar. — June 30, a distinct but very feeble growth; it is visible to the naked 
eye in the V and on the slant, if the tube is held up to the light, but it is best seen 
with a Zeiss X 6 aplanat; under this magnification there appear to be 300 or 400 
tiny whitish colonies on the slant surface, and in the fluid a feeble clouding and 
some tiny zoogloese; no yellow color is visible. July 2, a streak composed of 
several hundred small white colonies barely visible to the naked eye. July 5, a pale 
yellow growth now covers about 1 sq. cm. in the lower part of the streak. July 9, 
some increase of the yellow growth, but not over one-third of the slant covered; 
farther up there are more than 100 minute colonies, which can be seen only with a 
lens. July 16, growth on the lower part of the. slant has doubled and is yellower 
than it was (buff-yellow) ; the tiny colonies on the middle and upper part of the slant 
have not increased any in size; they are dead; the agar has dried out but little. 

B. pyocyaneus-pericarditidis: 
(a) Potato.— June 30, no visible growth. July 2, an abundant growth, whitish 
with a tinge of yellow; no fluorescence. July 5, potato grayed throughout. July 9, a 
thin dirty white (or brownish white) growth; no fluorescence; growth in the air 
not retarded by the hydrogen. 
B. aniylovortts: 
(a) Potato. — June 30, no growth. July 2, fluid well clouded and a distinct white 
growth on the potato out of the water. July 5, fluid heavily clouded; potato feebly 
grayed; growth in the air not retarded. 
B. coli: 
(a) Potato. — June 30, fluid well clouded, doubtful as to growth out of the water; 
if any, it is slight and of the same color as the potato; potato not grayed. July 2, 
scanty wet-shining white growth on the potato out of the water; organism will 
grow in hydrogen. 



81 

(2) The sccoiul test was })ei>un ,)une 16 and closed July 1. Four 
media Avere used, viz, +15 peptonized beef broth (stock lT3a), peptone 
water with addition of grape sugar and methylene blue (stock 489), 
peptone water with sodium chloride and rosolic acid (stock 1:93), and 
Uschhisky's sohition (stock 196). Various organisms were tested. 
Each tu1)e received an equal quantit}' of the culture fluid, i. e., one 2mm. 
loop of cloudy l)roth from cultures live days old. The media used had 
already- l)een tested and the various organisms were known to grow 
well in it. The inoculations were all made from media in which the 
various organisms grew well, viz, peptonized beef broth neutral to 
phenolphthalein (stock 515e). The general management of the experi- 
ment in other particulars was the same as in the preceding. 

The seal was broken, as before, on the sixteenth day (Julyl), and the 
results were as follows: 

Ps. hyacinthi: 

(a) Beef broth. — Julyl, no growth. July 2, clear. July 5, clear. July 9, clear. 
July 16, feebly clouded; good rolling clouds on shaking; a great retardation of 
growth. 

(b) Gh'dpe sugar peptone water ivith methylene blue. — July 1, no growth; on removal 
the fluid was nearly colorless^, but the surface layer in contact with the air immedi- 
ately became greenish l^lue and in a few minutes the whole fluid was t)xidized to this 
color; this result also shows that the jar remained free from oxygen. July 2, clear, 
.July 5, clear; July 9, clear; no visible growth. July 16, well clouded; color wholly 
reduced, except in a thin layer at the top next to the air; this gnjwth and reduction 
of color began about July 12, on shaking, the color comes back, but is again reduced 
on standing for a few minutes; marked retardation of growth. 

(c) Salted peptone vmter tiMtli rosolic acid. — July 1, no growth; color of the fluid 
the same as in the uninoculated tubes. July 2, clear. July 5, no growth. July 9, 
clear. July 16, no growth visible; no change of color. 

Ps. campestris: 

(a) Beefbrotli. — Lost by breaking. 

(1)) Grape i^ngar peptone vndet' ivitli viethylene blue. — July 1, no growth; fluid nearly 
colorless when taken from the jar; on contact with the air it began to color at once and 
in a few minutes was greenish blue. July 2, clear. July 5, clear. July 9, clear. 
July 16, fluid greenish blue; no growth. 

(c) Salted pejHone water tnth rosolic acid. — July 1, no growth; the fluid is the same 
color as when iiKx-ulated. July 2, clear. July 5, no growth. July 9, clear. July 
16, clear; no cliange in color. 
P.s. steicart'i: 

(a) Beef hrolli. — July 1, no growth. July 2 (temperature 28° C. ), very feebly 
clouded. Jul}- o, moderate clouding, most in the upper 6 mm. where there are numer- 
ous small zooglaea3 wl ich stream down on gentle shaking; much increase in growth 
since July 2, >)ut no rim or pellicle; July 9, moderately cloudy; no rim, but a delicate 
pseudo-pellicle of separate z(3oglcp;p. July 16, feebly clouded.; a moderate amount 
of yelhnv precipitate and a thin fragile yellow iridescent pellicle, which breaks up 
on slight shaking into a great many roundish zoogloefc; growth in the air not dis- 
tinctly retarded. 

(b) (traj)e .sugar jieploiie tvalcr witJi methylene blue. — July 1, clear. There seems to 
have been a little growth — i. e., there are a few tiny floating flecks of uncertain 
iKiture, there is a small amount of colorless j)recipitate which is wanting in the cor- 

21788— No. 28— OL 6 



82 

responding tubes of P.s. liyacinthi and P.s-. campesfris, and the reduced fluid oxidizes 
back on contact with the air to a c(jlor which is l)hiei' than that in the tubcH already 
mentioned, and which resembles that in a tube of Jones's carrot rot organism {Bacillus 
(■(irotovorus) , where there has certain!}' ])een some growth. July 2, feebly clouded; 
rolling clouds on sliaking. July 5, feebly clouded. July 9, clear or very nearly so; 
no rim or pellicle. July 16, clear; no reduction; fluid a pure blue; a feeble growth 
after removal to the air, l)ut no marked retardation. 

(c) Snlted pe^^tione water with rosolic acid. — July 1, no growth; fluid the same co'dr 
as when inoculated. July 2, clear. July 5, there seems to be a slight deepening of 
the color, the clouding is not distinct. July 9, not much change. July 16, as on the 
9th; fluid slightly pinker than in the corresponding tubes of Ps. hyacinth i and J'x. 
cajiijwstri.s; not cloudy. 

(d) Uschinnky' s KohUion. — July 1, no growth. July 2, clear. July 5, clear. July 
9, clear. July 16, clear; no growth. 

B. jjyocyaneus pericarditidis: 

(a) Beef broth. — July 1, a slight growth, which has not increased any of late; the 
fluid is clear and there is no rim, but there is a small amount of precipitate (10 nun. 
wide), and a bacterial film invisible to the naked eye, but distinct under the lens, 
and covering al)out one-sixth of the surface. July 2, moderately cloudy; fluid 
green fluorescent in the upper one-fourth and bearing a thick white pellicle. July 
5, very heavy clouding and a marked increase of the fluorescence; an abundant 
white i)recipitate, a thin white rim, and a white pellicle which settles easily on 
jarring. July 9, very cloudy, Imt fluorescence not pronounced. July 16, fluid 
well clouded; very ropy; only slightly fluorescent, feebly browned; precipitate 4 
mm. deep; no retardation of growth after removal to the air. 

(b) Grape sugar peptone ivater with methylene bhie. — July 1, no growth or only the 
merest trace; fluid nearly colorless; it becomes greenish in a few minutes on 
exposure to the air. July 2, fluid clcjuded, with a thin pellicle; color half reduced. 
July 5, fluid well clouded and uniformly blue, if any reduction of color it is uni- 
form; some of the pellicle has fallen; under the fluid there is a thin white rim 
1^ mm. wide. July 9, cloudy blue with a thin white rim and pellicle. July 16, 
the pellicle has fallen; the fluid is pure blue; there is no distinct fluorescence or 
reduction of color. 

(c) Salted peptone water with rosolic acid. — July 1, a trace of growth; not cloudy, 
but with a slight precipitate and a membranaceous pellicle visible only under a lens; 
no rim. July 2, fluid clouded, pellicle more distinct; the color has turned toward 
pink. July 5, moderately cloudy; no pellicle, that of July 2 lies on the bottom 
unbroken; there is a thin rim under the surface of the fluid; the latter is now- 
bright pink; it was originally yellowish rosaceous and the uninoculated tul)es are 
still that, color. July 9, nmch as on 5th. July 16, fluid moderately cloudy, color 
bright pink red. 

' B. amylovorus: 

(a) Beef broth. — July 1, clear; no present growth; there is a slight precipitate, 
chemical (?); it is much less than in case of B. roli. July 2, clear. July 5, clear. 
July 9, clear. July 16, clear; no growth, unless possibly when first placed in the 
hydrogen. 

(b) Grape sugar peptone water with methylene bine. — July 1, no growth; fluid nearly 
colorless when removed, but soon changing to a greenish blue, as in case of Ps. hyacinthi 
and Ps. campestris. July 2, clear. July 5, clear. July 9, clear. July 16, no reduc- 
tion; no clouding; fluid "pure blue." 

(c) Salted peptone water 7vith rosolic arid. — July 1, no rim, pellicle, or clouding. 
A slight rosy precipitate (2 mm. wide), which is possibly chemical; the color of the 
fluid is the same as when inoculated. July 2, clear. July 5, no growth; no change 
in color. Julv 9, as on the 6th. Julv 16, as on the 5th. , 



83 

B. roll: 

(a) Beif hnith. — July 1, Home growth; no rim or pellic^le; only the merest trace 
of clouding and no rolling cl<iudy on shaking, but a white precipitate 10 mm. l)road. 
July 2, well clouded; a thin white rim, and a gathering of zooglrepe into the upper 
layers which are cloudiest. July 5, heavily clouded, more so than on the 2d; a 
thin white pellicle and a white rim 8 mm. wide. July 9, as on the 5th; the pelli- 
cle settles on very gentle shaking. 

(b) (rrupc sugar prptoiii' initcr wiUi inetliyJenc blue. — July 1, a slight growth; fluid 
feebly clouded; no rim, but some slight fragments of pellicle and a precipitate 4 mm. 
wide; fluid nearly coh^rless; on exposure to the air the fluid becomes bluish, i. e., 
like the carrot-rot culture; the uninoculated tubes are greenish. July 2, heavily 
clouded; there has been no reduction of the color; it is now a pure ))right blue 
(brighter than yesterday) . July 5, well clouded; no rim or pellicle; fluid (by trans- 
mitted light) a uniform l)right blue. July 9, as on the 5th. July 16, fluid pure 
blue, no reduction of color; moderately cloudy, no rim, no pellicle; a scanty bacterial 
precipitate which is blue. 

(c) Salted peptone water with rosolic add. — July 1, a rosy precipitate 3 nun. wide; 
no clouding, no rim, no pellicle. July 2, moderately cloudy; fluid is changing to 
pink. July 5, well clouded; no rim or pellicle; fluid deep pink; at least twice as 
much color as in the corresponding tube of B. jjyocyaneus pericarditidis. July 9, as 
on 5th. July 16, feebly clouded, slight precipitate; no rim or pellicle; fluid deeper 
red than that in the corresponding tube of B. pyocyaneus-pericarditidis. 

. Growth in Carbon Dioxide. 

The carbon dioxide was prepared in quantity in a Kipp generator 
from boiled marble chips and c. p. hydrochloric acid diluted with dis- 
tilled water (1 part acid, \) parts water). The gas was allowed to flow 
until all air was displaced from the apparatus. It was washed in 1 
per cent caustic potash water and then in distilled water. The tubes 
were exposed in a deep specimen jar with a flat brass top provided 
w^ith inflow and outflow tubes having very perfect stopcocks. When 
all was ready a waxed rubber gasket was laid on the top of the jar and 
the solid l)rass top was clamped down securely. The jar was first 
exhausted of air utitil the mercury stood at 3 inches. It was then 
tilled with the CX)., five times, and as many times pumped out. After 
the sixth tilling th(> stopcock was turned off' and everything sealed 
securely. Preliminary exhaustion tests had shown onl}^ a slight leak- 
age, i. e,, in 2-4 hours the mercury in the cistern barometer rose only 
from 2i to 3i inches. 

The following media were tested: Tubes of beef l)roth Tieutral to 
phenolphthaiein (stock 382); tubes of potato (stock 405); tubes of 
coconut (stock 412); slant beef -extract peptone agar neutral to litmus. 
Each tube was inoculated copiously and in the same way, i. e., with 
large loops from well-clouded beef ])roth cultures 13 days old. Two 
or more tubes of each medium were inoculated and one of each medium 
was held as a check. The exposui'e was begun March 10 and the tubes 
were removed to the air after 1(» days, i, e., on March 2<>, On taking 
off the brass cover, lighted matches were repeatedly plunged into the 



84 

jar und as often extinguishod. They went out instantly they were 
depressed l)elow the level of the top of the jar. The checks behaved 
well. On the sixth day in each one there was a w-ell-developed typical 
growth of the particular organism used. 

The results obtained in the COg and on continuing the cultures in 
the air are stated below. The temperature during the experiment did 
not Viiry much from 22° C. 

Pg. Iii/(n-iiitlii: 

(a) Beef />ro//(.— March 20, no growtli. :Slaifli 21, clear. :\Iarch 23, no growth. 
March 27, moderately cloudy with rolling i-louds on ^;haking; a slight precipitate. 
March 31, well clouded; growth retarded by the CO.. 

(b) Po/(//o.— March 20, no growth. March 21, no growth. March 23, no growth. 
March 27, a typical growth, wet and dis^tinctly yellow on the lower one-half of the 
exposed part of the potato; that part out of the water is graying. March 31, the 
yellow slime now covers all of the potato out of the water. 

(c) Potofo.— :March 20, no growth. :March 21, no growth. :\Iarch 23, no growth. 
March 27, same appearance as in the jireceding; growth retarded by the COj. March 
31, like the preceding. 

(d) CoconwL— March 20, no growth. :MaR-h 21. a thin yellow growth now covers 
about 1 sq. cm. ; growth in the air not retarde<l l)y the exposure. March 23, a thin 
distinct yellow growth now covers 6 to 7 sq. cm. March 27, 9 sq. cm. of bright 
yellow growth. 

(e) CocfMuL— March 20, no growth. :\Iarch 21, a thin, yellow growth now n.vers 
about 3 sq. cm. March 23, like the preceding. :\Iarch 27, like the preceding. 

Ps. campedris : 

(a) Beefhroth.—Maxvh 20, no growtli. :Marcli 21, clear. March 23, no growth. 
March 27, no growth. March 31, no growth; fluid still alkaline; it was now rein- 
oculated with a small amount of yellow slime from potato culture />, and on April 5 
was well clouded with a yellow rim and numerous zoogloese; exposure to CO.^ 
appears to have destroyed the organism. 

(b) Potato.— March 20, no growth. :\Iarch 21, no visible growth. March 23, a 
feeble pale-yellow growth now covers part of the potato; growth retarded by the 
COj. March 27, a copious wet-looking, distinctly yellow slime on the exposed parts 
of the potato and in the fluid. 

(c) Potato.— March. 20, no growth. March 21, no visible growth. IMarch 23, 
resembles the preceding— less growth but more color; growth retarded. ^larch 
27, like the preceding. 

(d) C'oco;mL— March 20, no growth. March 21, no visiVjle growth. INlarch 23, a 
thin yellow growth now covers 5 sq. cm. March 27, a yellow growth now covers 
nearly all the cylinder out of the water; no distinct retardation. 

(e) Coconut.— March 20, no growth. ]\Iarch 21, no visiVjle growth. March 23, a 
thin yellow growth covers 3 sq. cm. :March 27, like the preceding. 

Ps. stewarti: 

(a) Beef broth.— March 20, no growth. March 21, clear. March 23, no growth. 
March 27, no growth. March 31, no growth; reinoculated with a small amount 
of slime from the coconut culture cl On April .5 the culture was well clouded and 
had a good rim; exposure to the CO.^ appears to have destroyed the organism. 

(b) Potato.— March 20, no growth. March 21, no visible growth. March 23, a 
feeble, patchy, buff-yellow growth now covers 6 sq. cm. March 27, a typical buff- 
yellow growth; marked graying of the potato in the air. 

(c) Potato.— March 20, no growth. March 21, no visible growth. March 23, a 
feeble, patchy, buff-yellow growth covers 3 sq. cm.; neither potato has grayed. 
March 27, like the preceding. 



85 

(d) Coconut. — March 20, no growth. March 21, extremely thin (barely visible) 
bnff-vellow growth over 3 sq. cm. March 23, a thin, pale, buff-yellow growth now 
covers al)Out 5 sq. cm. March 27, a rather scant buff-yellow growth over 8 sq. cm. 
No retardation. 

B. amylovorus- 

(a) Affcir. — March 20, no growth. March 21, a distinct growth on the lower end 
of the slant. March 23, the white growth slowly increases. 

This closes m}" studies of the aerobism of Ps. hyacinthi and related 
species. All the various experiments lead to substantially the same 
conclusions: (1) Px. hyacinth! and the other yellow species of Pseudo- 
monas are more strictly aerobic than most species of bacteria; (2) while 
somewhat variable among themselves none of these yellow-plant para- 
sites will survive exclusion of oxygen for more than a very few weeks; 
(3) nitrogen, hydrogen, and carbon dioxide seem to be only negatively 
harmful; (-1) the organisms were more tolerant of these gases on some 
media than in others. They were especially susceptible in beef broth, 
in peptone water, and on agar. 

RELATIVE NUTRIENT VALUE OF CARBON COMPOUNDS. 
Bouillon and Peptone Water with Various Sugars, etc. 

The few results obtained may be summed up as follows: 

(1) A feeble clouding was obtained with Ps. hyacwthi in a fluid con- 
sisting of 1 part of strongly alkaline beef broth (286b) in 500 parts of 
distilled water. Ps. campestrls and Ps. 2>haseoll also clouded this fluid. 
These cultures were made in clean tubes of resistant glass. 

(2) Ps. hyacinthi grew readily in distilled water containing 1 to 2 
per cent of Witte's peptonum siccum, and the precipitate was yellow. 
Growth in I per cent peptone water in the open end of fermentation 
tubes, as we have already seen, was increased by the addition of 1 per 
cent doses of grape sugar, fruit sugar, cane sugar, or dextrin, and 
was not perceptibly increased by the addition of 1 per cent doses 
of milk sugar, maltose, mannitol, or glycerol. If under these condi- 
tions any acid was formed from any of these substances^ it was over- 
looked or obscured by the alkali. 

(3) In distilled water (10 c. c. portions in tubes of resistant glass) 
containing -1 per cent of Witte's peptonum siccum and 4 per cent of 
dextrin there was little or no retardation of growth. On the tAvelfth 
day the fluid was plainly alkaline to litmus. On the twenty-ninth 
day there was an a])undant yellow rim and a very copious dull-yellow 
precipitate (<> nnn. deep). The cloudy fluid was plainly and rather 
strongly alkaline. On this date there was several times as much pre- 
cipitate as in the corresponding tubes of Ps. carnpestris and Ps. plmstikli. 
On the fortieth day the fluid was strongly alkaline. It was still cloudy 
with rolling clouds on shaking, and thcrc^ was no brown stain in it. 
On the sixty -fifth day the fluid was moderatel}' alkaline. No crystals 



86 

were present, and a feeble brown stain, thought to have been 
detected on the fifty-fourth day, was not well enough developed to be 
recorded as certainly present. On this date there was more than twice 
as much precipitate as in the corresponding tube of J^s. catnpestris. 
This dextrin had been ten times precipitated with alcohol in the 
Division of Chemistry, United States Department of Agriculture. It 
gave a heavy yellowish precipitate on boiling 1 minute in Soxhlet's 
solution, ])ut no precipitate on boiling 2 minutes in Barfoed's reagent. 

(4) In distilled water (10 c. c. in tubes of resistant glass) containing 
4 per cent of Witte's peptonum siccum and 4 per cent of maltose 
there was no retardation of growth, and for the first week or so the 
culture closely resembled the preceding. On the twelfth day the fluid 
was distinctly alkaline to litmus, but it was less cloudy than the pre- 
ceding and there was far less precipitate. On the twenty -ninth da}" 
the fluid was plainly and rather strongly alkaline, but there wa; only 
about one-tenth as much precipitate as in the tube containing the 
dextrin. On the fortieth day the fluid was still cloud}-, but was not 
browned. The rim was not very aljundant and was paler than in the 
preceding. The precipitate was the same shade of pale yellow as in 
the tube containing the dextrin, but there was only one-tenth to one- 
fifteenth as much. On the sixty-fifth day the fluid was strongly 
alkaline, but both in this and in the preceding the blue color soon 
disappeared from the neutral litnuis paper, leaving it redder than 
before. No crystals were formed. 

In the corresponding tube of Ps. canipestris there was a distinct 
browning of the fluid, which was first noticed on the fortieth day. 
Ps. p]i((f<eoli browned neither fluid. 

Crude Vegetabi.e Substances. 

The behavior of Ph. hyacinthi in contact with steam sterilized solids 
and fluids derived from plants has been discussed so fully under 
Sensitiveness to acids and Growth on solid media that it is only neces- 
sar}'^ here to recapitulate a few of the more important discoveries. 

(1) All my observations tend to show that plant acids, even in 
comparativel}' small doses, prevent growth, and that still smaller 
quantities retard growth. It is, therefore, probable that these acids 
do not serve directly as food. Certainly the behavior of this organism 
in nutrient fluids containing malic acid is extremely unlike that of 
organisms which are believed to use this acid as a food, e. g. Bacillus 
amylovortis. 

(2) Starch, as we have seen, is transformed into substances which 
can be assimilated onl}^ with the greatest difliculty. 

(3) Growth on steamed vegetables poor in sugar was always rather 
meager. Substrata containing rather more sugar gave a correspond- 
ingly better growth. 



87 

(4) Growth on vegetables rich in grape sugar or cane sugar was 
copious and long continued. These two sugars are excellent foods, 
and when not present in such excess as to inhibit growth (probably by 
plasmolysis) they greatly favor the multiplication of this organism. 

Sugar Gelatin. 

(See Growth on solid media.) 

Sugar Agaes. 

Some interesting results were obtained b}^ adding large doses of 
sugar to 10 c. c. portions of Mr. Dorsett's +15.5 meat-extract peptone 
agar (see Growth on solid media) and growing on it the various yellow 
organism in slant cultures. Their behavior on these media was always 
compared with that on chock tubes of the sugar-free agar. 

NINE PER CENT .SUGARS. 

First Series. 

Agar recently tubed and slanted (10 cc. to 1 gram of the sugar) . Inoculations with 
Ps. liyacinthi, using bright-yellow slime from a starch jelly culture 28 days old. All 
the inoculations were made in the same way and with approximately the same 
amount of material. 

Third day. 

(1) Check. — Streak 2 by 75 mm., distinct the whole length of the track, best devel- 
oped at the lower end, where it is distinctly pale yellow. In the middle 3 c. m. it 
consists of separate colonies. 

(2) drupe sii(j<(r {l,grarii of Merck's c. p. anhydrous). — Streak invisible except in 
a very favorable light, where it looks like a colorless film. 

(3) ('(oic muftr [1 gram of ir}dte commercial). — A thin pale yellow growth over 
the whole slant. In strong contrast witli the grape-sugar agar. Also more growth 
than in the dieck tube. 

Seventh day. 

(1) Check. — The streak is now 3 to 5 mm. wide. All of the colonies have fused 
into a smooth, yellow, wet-shining homogeneous surface. 

(2) Grape sugar. — (irow'th mostly in the form of separate colonies and less than in 
the check tube — i. e., a distinct retardation. There are many of these colonies, and 
where they have coalesced the color is about the same shade of yellow as in the 
check tube. 

(3) Cane sugar. — The whole surface of the slant agar is covered and hidden by a 
copious pale yellow growth. Six times as much growth as in the check tube and 8 
or 10 times as much as on the grape-sugar agar. 

Sixteenth day. 

(1) Check. — The streak has not wideiu'd any. It is smooth, translucent, wet- 
shining, anil distinctly pale yellow. The margins of the streak are thin but distinct. 
A penholder is plainly visiV)le under the streak. 

(2) ''.'/vfyv .sv/^fH'. — ( irowtli has (luadruplcd and is now about 3 times as abundant 
as in the check tube, but its surface is very unlike that of tlie latter. The surface, 



88 

which h i>ale yellow, has a peculiar rougliened or areolate appearance, which 
appears to ])e due to wrinkles extendinir in various directions. The shallow pits are 
2 to 3 nun. in diameter. 

(3) CWn<' .sug^or.— Fully 6 times as much growth as in the check tul)e. The pen- 
holder can not be seen under it. Color pale yellow, a little paler than in the check 
tube. Surface not smooth as in the check tube nor wrinkled as on* the grape-sugar 
agar, ))ut finely roughened. 

Twenty-nintli day. 

(1) CZ/rt-A-.— Little change. The streak is 3 to 6 mm. wide. Its surface is smooth 
and wet-shining, and to either side, on the lower part of the slant, there is a slight 
chemical whitening of the surface of the agar. No l)rown stain. 

(2) Graj)e sugar. — About 4 times as much growth as in the check tube. The 
bacterial layer covers all but the upper part of the slant and there is some growth 
between the agar and the walls of the tube. Growth the same shade of yellow as in 
the check tube, or only a trifle ])aler. No brown stain. No whitish chemical film 
on the agar beyond the .streak. Surface wet, but not smooth as in the check tube. 
The extreme upper part of the streak is still composed of separate colonies, and the 
rest of it is areolated i. e., covered with tiny ridges and depressions. 

(3) Cane )<ugar.— Color uniformly pale yellow. Surface drier than it was and 
slighth- roughened, but not coarsely areolate, as on the grape sugar agar. Streak less 
translucent than in the cheek tube, i. e. almost opaque. No brown stain. The cul- 
ture has a feeble smell. On boiling the contents of this tube for one minute in 
Soxhlet's solution there was a very heavy precipitate of copper oxide. Sugar and 
agar had both l:>een tested for reducing substances previous to inoculation and neither 
one gave any trace of copper oxide on boiling two minutes in Soxhlet. The slime 
remaining in the tube was very feebly alkaline to litmus, i. e., much less alkaline 
than might have been expected from the amount of growth. This is presumptive 
evidence that most of the alkali had been neutralized by some acid. 

Forty-seventh day. 

(1) Cherl:— The streak is drying out. It is (Jo l)y 3 to 6 mm., i. e., it has spread 
but little. It is still smooth, wet-shining, and so translucent that a penholder can 
be seen through it. The streak has well-defined margins, beyond which the surface 
is feebly whitened. On neutral litmus paper the saffron-yellow slime has an alka- 
line reaction. Examined microscopically, this slime consists of zoogloe» and siiort, 
slender rods, single or in pairs. Rods in fours are rare, and chains are short and 
exceedingly rare. 

(2) Grape sugar.— The liacterial layer is gallstone yellow. It now covers almost 
the entire slant (70 by 16 nun. ), and is about 20 times as abundant as in the check 
tube. It scrapes off easily and gives an acid reai'tion on neutral lituuis jjaper. A 
few separate colonies persist on the ujiper dried-out part. The surface is not smooth, 
but roughened, and wrinkled slightly in the lower part of the slant. Examined 
microscopic-ally, the slime consists of zooglrtw, chains, and short, slender rods, 
single, in pairs, or in fours. Chains of 10 to 20 or more segments are numerous. In 
some the individual segments are easily discernible, in others not. Apparently 
some of the rods are motile. No spores. 

(3) Carie sugar {aiwfJwr lube of ihe same age, hut containivg onhj 6.75 per cent of 
.sugar) .—Growth dense and finely roughened (fine wrinkles under the hand lens). 
No brown stain. No crystals. No chemical film. At least 10 times as much growth 
as in a check tube. Slime, buff yellow (R. VI-19), acid to neutral litmus paper. 
Examined microscopically, the slime consists of zoogl(e;e, numerous chains of 10 to 
40 segments, and many single rods, i)airs, and fours joined end to end. In many of 



89 

the chains, but not all, the individual elements are visible. No spores. The niiero- 
scopii' appearance closely resembles that of the slime from the grape-sugar agar, the 
principal difference l>eing the tendency to longer chains or filaments. 

Second series. 

The check tube had the driest surface; the surface oi the fruit-sugar agar was the 
moistest. Inoculations from a slant-agar culture of Ps. hyadnthi 13 days old. All 
made in the same way and with approximately the same amount of material. 

Third day. 

(1) Check.— Streak 78 by 5 to 12 mm., pale yellow, translucent, smooth, wet- 
shining, homogeneous looking, and not scanty, i.e., a good growth over the whole 
length of the slant. 

(2) Fruit sugar {1 gram of Schrring'n 'Jiabetine). — No growth, although inoculated 
just as copiously. 

(3) Grape sugar [1 gram of MercF x c p. a)ihf/drous).—A ieehXe growth consisting 
of scattered colonies which, in some places, have fused into a very thin layer. Not 
one-twenty-fifth as much growth as in the check tube. Grape sugar in 9 per cent 
doses distinctly retards growth. (This growth doubled during the next 24 hours.) 

Fifth day. 

(1) Check. — Much as before. 

(2) Fruit sugar. — No growth. 

(3) Crra;je A-Np-t/r.— There is now nearly as much growth as in the check tube. The 
lower one-half of the slant is covered, and the upper one-half bears scattering yellow 
colonies. The surface is not smooth, as in the check tube, but is distinctly shagreened 
to the naked eye. The yellow slime is very feebly alkaline, inducing only the barest 
trace of blue on wet or dry neutral litmus paper. 

Eighteenth day. 

(1) Check.— A thin, smooth, moist, pale-yellow slime covers nearly the entire 
slant. There is no brown stain in the agar. 

(2) Fruit sugar. — No growtli. Fragments of the moist agar pressed on neutral 
litmus paper redden it. 

(3) GrajK sugar.— A copious, pale-yellow, coarsely wrinkled growth now covers 
the whole slant. This layer scrapes off easily, and is very feebly alkaline to neutral 
litmus paper. There is no V)rown stain in the agar. 

Fifty-third day. 

(1) Check. — Slime feebly alkaline. 

(2) Fruit sugar.— 1^0 growth. Failure to grow was attributed to the' restraining 
influence of lactic acid juit into this sugar by the manufacturers to improve its 
keeping iiualities. 

(3) (Iraj)i' sugar. — Streak somewhat wrinklc<l and on the margins slightly areolate. 
Slime now distinctly acid to lunifral litmus paper, no trace of any alkaline reaction. 
Culture diluted (shaken) with 40 c. c. of distdled water and retested. It is now 
neutral or oidy very feebly aciil. On boiling this watei- a little acid is given off in 
the first vapors (CCy), but less than from a corresponding culture of Ps. canipestris. 
On concentrating this llnid by continued boiling it became plainly more acid to 
litmus ])aper, indicating the i)reseiu'e of a small anioiuit of some non-volatile acid. 
Cultures of Ps. camjjcslris behaved in the same way. 



90 



RENEWED EXPERIMENTS WITH FRCCTOSE. 

The fructose (Schering's diabetine) was first titrated with caustic 
soda and litmus to determine its acidity. This was such that 10 c. c. 

\ 

of j^ NaOH were required to render 10 g-rams moderately alkaline 

to litmus. One-half c. c. of this thick alkaline sirup was then pipetted 
into 7 c. c. of Dorsett's agar for one experiment and 1 c. c. of the sirup 
into 10 c. c. of the agar for another experiment. The agar was then 
resterilized and slanted in the usual way. The check tubes had been 
slanted longer than the others and their surface was somewhat dr^^ 
All were inoculated with Pn. hyacintkl from a slant agar culture 24 
days old, in the same wa}' and with approximately the same amount of 
material. 

Second day. 

(Ij Check. — A feeble growth in the form of scattered colonies. 

(2) Fruit sugar {one-half e. c. sh'up). — A feeble growth, which was visible sooner 
than in the check tube, i. e., within 18 hours. 

(3) Fruit sugar (1 c. c. sirup). — A very slight growth, not one-fourth as much as in 
the preceding. 

Fourth day. 

(Ij Check. — Not a good growth. It occurs colony-wise over the streak. This agar 
had been slanted a long time and the surface was becoming too dry for good growth. 

(2) Fruit sugar {one-half c. c. siru})). — A distinct multiplication during the last 48 
hours, but not yet a homogeneous streak, i. e., growth thin in some places and more 
abundant in others. Not yet more growth than would have appeared in the same 
time on a freshly slanted check tube. 

(3) Fruit sugar {1 c. c. sirup). — Very little growth, i. e., not one-twentieth as much 
as in the preceding. This substratum evidently retards growth. 

Seventli day. 

(1) Check. — A much better growth. The colonies touch or nearly touch, forming 
a thin, distinctly yellow slime over nearly the whole slant. 

(2) FVuit sugar {one-half c. c. sirup) .—There is now more growth than the agar alone 
would give. The streak is dense and rather abundant (47 by 10 mm. ), pale yellow, 
smooth, and wet-shining. 

(3 ) Fruit sugar {ic. c. sirup ) . — Growth very feeble. There has been a slight increase 
during the last 3 days, but the growth is not now one one-hundredth, perhaps not 
one one-hundred-and-fiftieth, a.s much as in the preceding tube. 

Twelfth day. 

(1) Check. — The colonies, for the most part, have now fu.sed into a smooth surface. 

(2) Fhmit sugar {one-half c. c. sirup). — A very copious, pale yellow, smooth, wet- 
shining growth covers the whole slant, and is growing in between the tube and the 
agar. At least 4 times a.s much growth as in the check tube. 

(3) Fruit siujitr {1 c. c. sirujj). — The restraining influence is being overcome. About 
one-third as much growth as in the preceding, and excellent where it has obtained a 
foothold. This growth is of the same character as in the preceding. 



91 

Sixteenth day. 

(1) C'/iec/:.— Growth decidedly yellow, still thin. ■ 

(2) Fruit sugar {one-half c. c. .sirup).— Growth has continued. It is wet-shining, very 
smooth, and extremely copious. About 10 times as much growth as in the check 
tube. Fructose distinctly favors growth unless all of this excess is attributable to 
the sodium lactate formed by neutralizing the lactic acid, which is extremely improb- 

aV)le. 

(3) Frml sugar {1 c. c. sirup). — A marked increase of growth during the last 4 
days. A considerable part of the slant which was then free is now covered. The 
slime is i>ale yellow; the surface is very smooth and wet-shining. 

Thirtieth day. 

(1) Gieck. — Surface so dry that not ail of the colonies have fused. No crystals. 
No stain of the agar. 

(2) Fruit sugar {one-half c. c. siru})).— The pale yellow, wet-shining, smooth slime 
is 3 mm. deep over the whole surface of the slant. The color is dull yellow, but there 
is no reason for thinking it contaminated. No brown stain. No crystals in the 
agar. Growth has been enormously stimulated by this sugar. 

(3) Frintmgar [1 c c. sirup). — The entire surface of the slant (15 by 53 mm.) is 
now covered with a pale yellow, smooth, very wet-shining slime. There is no brown 
stain, and there are no crystals in the agar. 

SEVENTEEN PER CENT SUGARS. 

Mr. Dorsett's +15.5 sugar-free agar was also the basis of all of these tests. Each 
tube contained exactly 10 c. c. of agar to which was added 2 grams of the sugar to be 
tested. The slant surfaces were all inoculated in the same manner, and with approxi- 
mately the same amount of material, viz, loops of bright-yellow slime from a coconut 
culture 8 days old. 

First day (22 hours at 27° to 30° C). 

(1) Check. — A distinct, wide, pale yellow streak. 

(2) Grape sugar {2 gr. Merck's c. p. anhydrous). — Streak not visilile. 

(3) Qme sugar [2 gr. white commercial). — A meager growth. Gne-tenth to one- 
twentieth as much as in the check tube. For the most part, tlie streak is mvisible 
and nowhere shows more than a trace of growth. 

Fourth day (temp. 27° to 31°). 

(1) Clieck.— 'Streak smooth, wet-shining and rather bright yellow, but not dense 
enough to be opaque. It is 72 by 5 to 6 mm. The margins of the streak are distinct 
and there is no whitish efflorescence on the surface of the agar arcjund tlie streak. 

(2) drape su.g(tr.—Do\\hiiu\. No visible growth excei)t in very favorable lights. 
If any growth at all, not one one-hundredth as much as in the check tube. There 
can be no doubt that 17 per cent grape-sugar agar exerts a very distinct retarding 
influence on I's. hyacinth i. 

(3) Cane sugar.— A well-developed streak 62 by 5 to 8 nun. It appears to beas dense 
as in the check tube, but is paler yellow, i. e., the color is exactly that of a 4 days' 
growth of I's. (■a)iipeslris on tlu^ check agar. This tube and the check tul)e are in 
marked contrii,«t with the preceding. 

Eighth day. 

(1) Check. — The streak has thickened ;i little, but has not wid('ne<l. 

(2) drape sugar.— \\\vAt looked on the fourth day like mere drieil-out portions of 
the slime used in making the inotuilation has now devehjped as a distinct growth in 



92 

two places, aggregating 2 square cm. "Where the organism has secured a foothold the 
slime is distinctly pale yellow, but much of the part which was streaked hears no 
growth whatever, and altogether there is not one-tenth as much growth as in the check 
tube. The surface of this slime is not smooth, as in the check tube, but is mmutely 
fissured and roughened all over. 

(3) Cane augar. — As much growth as in the check tube, but paler yellow. Thus 
far the sugar has not stimulated growth. The streak is now 5 to 9 mm. wide. It 
has thickened some since the last record, but has not widened much. 

Thirteenth, day. 

(1) ('heel:. — Streak well developed, smooth, wet-shining, and distinctly yellow. 
The margins are well defined, and the body of the streak is not opaque, i. e. , the pen- 
holder can still be seen through it. It shows very little tendency to spread, i. e., it 
is still only 5 to 7 mm. wide. There are no projections from the under side of the 
streak into the agar (such growths appeared in case of an undescriVjed, white, spore- 
bearing organism, derived from rotting tomato fruits, and grown on this .same agar). 
There is now a slight but distinct bloom (chemical whitening) on the surface of the 
agar beyond the streak. 

(2) Grape augar. — About one-tliird, or i)Ossil)ly one-half as much growth as in the 
check tube. The color is the same, but the surface appearance is very different. 
The wet surface is not smooth, but is roughened, or areolated, as if made up of fused 
zooghe.'e with grooves between them. There is no chemical whitening of the sur- 
face of the agar beyond the streak. 

(3) Cane sugar. — Streak mostly 6 to 10 mm. wide. Surface drier and paler yellow 
than in the preceding or in the clieck tube. No growths into the agar from the 
under surface of tlie streak. Seventeen per cent cane-sugar agar is not nearly so 
favoraljleto the growth of this organism as 9 per cent. There is now but little more 
growth than in the check tube, whereas on the 9 per cent cane-sugar agar there was 6 
times as much growth in one-half this time, the temperature in both cases being 
approximately the same, i. e., near the optimum. 

Seventeenth day. 

(1) Check. — The yellow slime is jilainly alkaline to good neutral litmus paper, much 
more so than that on the grape-sugar or cane-sugar agar. 

(2) Grape sugar. — Slime neutral or very slighth' alkaline. 

(3) Cane sugar. — Slime neutral or only very slightly alkaline. 

Thirtieth day. 

(1) CIterk. — The streak begins to dry out. Its surface is smooth. There has been 
no widening. Beyond the streak the whitish chemical film remains, but is not very 
pronounced. No brown stain. No crystals. 

(2) Grape .'ill gar. — A pale yellow well-developed .<treak (50 by 5 to 9 mm.). It has 
not spread widely, and is still translucent. The surface is rather coarsely roughened 
and looks as if many large zooglcese had fused, leaving grooves between each one. 
The surface of the individual hummocks is smooth, wet-shining, firm, elastic, and 
scrapes off only after the use of considerable force. Examineil under the micro- 
scope, this growth consists of slender rods mixed in with some chains. The rods are 
single, in pairs, and in fours joined end to end. There is no brown stain. 

(3) Cane sugar. — The growth is now two or three times as abundant as in the check 
tube. It is very dense, especially on the lower part of the slant, where it is crowded 
up into high folds. The upper part shows lesser wrinkles. No brown stain and no 
chemical film on the clear agar to either side of the streak. The slime is pale yellow 



I 



93 

and very feebly alkaline. It is made up of small roundish zooglcese, short chains 
of a dozen or more segments, and slender short ro<ls, single, in pairs, or fours. Some 
of the rods are actively motile. 

Sixty-sixth day. 

(1) Check. — Slime strongly alkaline to neutral litmus. 

(2) Grape mgar. — Slime n(jt alkaline. Distinctly acid on neutral litnms paper. 

(3) Cane sugar. — No alkaline reaction. Slime distinctly acid on neutral litmus 
paper. 

TWEN'TV-THKKE I'KR (KNT .Sl'dAKS.^ 

These cultures were like the preceding- except that for each 10 c. c. 
of ag'cir 3 grains of the specified sugar was used. The check tubes 
had been slanted longer than the others and their surface was drier. 
All were smeared with Ps. Ivyacinthi from an agar culture 24 daj's old 
in the same way and with approximate!}^ the same amount of material. 
The alkaline fruit-sugar agars already described were inoculated at the 
same time and from this same culture, which was the check tube 
described under the 17 per cent sugar agars. 

Seventh, day. 

(1) Chech. — A thin distinctly yellow growth over nearly the whole slant. 

(2) Grape sugar {3 grams Merck's c. p. anhydrous) . — No growth. 

(3) Cane sugar {3 grams white comrnercial) . — A very feeble, scrappy growth, not 
forming a streak, but confined to the immediate vicinity of some small fragments of 
slime, which were left unspread when the agar was inoculated. Not more than two 
or three times as much slime present as was put into the tube in making the inocu- 
lation. Twenty-three per cent cane-sugar agar strongly retards growth. 

Twelfth day. 

(1) Clieck. — Fully twice as much growth as on the cane-sugar agar. 

(2) Grape sugar. — No growth, although the surface of the entire slant was rubbed 
with a mass of yellow slime as large as a pin head. 

(3) Cane sugar. — A distinct, rather thin, wet, yellow, rough-surfaced growth, which 
covers about one-half of the slant (lower half). 

Thirtieth day. 

(1) (Jhcrk. — Surface of the streak smooth, wet-shining, and distinctly yellow; no 
reticulations or shagreen. 

(2) Grape sugar. — \o growth. V'.s. hi/acliilhi \v\\\ not grow on 23 per cent grape- 
sugar agar. 

(3) Cane sugar. — The lower three-fourths of the slant is covered with a distinctly 
yellow growth, which is rather dry, Init looks wet under the hand lens. The surface 
is not smooth, but is reticulate, areolate, or shagreened, the portions between the 
grooves being lighter yellow and very smooth. This areolation is sliown in Bulletin 
26 of this Division, in text fig. 3, which was made from this culture on the thirty- 
third day. Theagarhas not dried out much, but the slime shows no tendency to flow. 



' The expressions 9,17 and 23 per cent are used for convenience. Of course, the 
writer is aware that 3 grams added to 10 c. c. does not make exactly 23 per cent. 



94 

Thirty-seventh day. 

(1) Check. — No record. 

(2) Grape >! I (gar. — No record. 

(3) Cane .'<ugar. —No crystals. No .«taiii in the agar. Tlie bacterial layer peels off 
easily in fragments, leaving a smooth, clean agar surface. This layer is not sticky or 
elastic, and dissolves with difficulty in water, V)reaking up into rather coarse frag- 
ments. Examined under the microscope, it consists of zooglcea}, single rods, doublets, 
and chains. The latter are 50 to 100 jti- long. 

.SUMMAKY OF RESULTS WITH SUGAR AGARS. 

(1) Z^-. Jiyacinth! grew without retardation on the check tubes, and 
the surface was always smooth. 

(2) Addition of per cent grape .sugar retarded growth. Finalh' 
growth was more abundant than in the check tubes, and the surface 
was areolated. 

(3) Addition of LT per cent grape sugar retarded growth for a longer 
time. This was linally more abundant than in the check tubes, and its 
surface was areolated. 

(4) Addition of 23 per cent grape sugar entirely prevented growth. 

(5) Addition of 9 per cent cane sugar did not retard grow^th, and 
after a few days greatly stimulated it. The surface was wrinkled or 
finely roughened. 

(6) Addition of 17 per cent cane sugar retarded growth. This 
finally became more copious than in the check tube, but it was never 
as abundant as on the 9 per cent cune-sugar agar. The surface was 
wrinkled. 

(7) Addition of 23 per cent cane-sugar agar retarded growth for a 
longer time, but did not prevent it. The surface was areolated or 
shagreened. 

(8) Addition of 9 per cent acid fructose {Schering's diabetine) 
entirely prevented growth. When the lactic acid was neutralized by 
caustic soda growth ensued, but was retarded for some time. In the 
end it was very abundant. 

Some interesting comparisons were obtained from concomitant cul- 
tures of /-^y. cain2)estri% Ps. phwitoU^ and 1\. stewarti. 

(1) On the check or sugar-free agar all three grew without retarda- 
tion, and did as well as Ps. kyacinthi. This agar was not stained 
brown and no crystals were formed, but the superficial white chemical 
film appeared whichever organism was used. This film also failed to 
appear on the sugar agars. whichever germ was u.sed. In the check 
tubes of each the slime was feebly alkaline at first and finalh' became 
strongly alkaline. On the contrary, with grape sugar or cane sugar, 
the reaction of the slime changed very slowly from alkaline to acid, 
whichever organism was used. All four invert cane sugar. All are 
alike in producing a small amount of non-volatile acid when grown on 



95 

this agar in the presence of grape sugar or cane sngar. All were much 
alike in color, l)ut frequently the hyacinth germ wa.s the brighter 
yellow. 

(2) The growth of Ps, campestris, Ps. phaseoH, and Ps. steunrti 
wa.s not retarded )>y 9 per cent grape sugar. On the contrary, it 
was stinudated from the veiV start. At the end of the iirst 48 hours 
on this agar P>i. cavipestris showed about twice as nmch growth, 
Pa. phaHeoU "more growth," and /^v. xtewarti four times as nmch 
growth as in the corresponding check tu])es. On the seventh da^^ Ps. 
campestris showed ten times as much growth as J^x. /li/acint/ii, and 
three times as nuu*h as in its own check tube (ten times as much on 
the sixteenth day). On this date Ps. p/mseoli had made twice as much 
growth as in the check tube (ten times as nmch on the sixteenth day). 
On the same date Ps. steiiiarti had made at least live times as much 
growth as in the check tube. 

In a second series of experiments with this agar Ps. campeatTis 
showed, on the third day, twice as much growth and Ps. phaseoli 
two and one-half times as much as there was in the check tubes. 
There was no retardation whatever. 

(3) Addition of IT per cent grape sugar retarded the growth of 
Ps. eamjjestris and Ps. phnseoli {Ps. stevMrtl was not tried), but they 
overcame the injurious influence sooner than A-. hyacinthi. If the 
volume of growth of Ps. kyacmthi on this agar on the sixth day be 
taken as 1, then that of Ps. ccmipestris was 10 and that of Ps. ])haseoli 
was 15 to 18. 

(4) Addition of 23 per cent grape sugar entirely prevented the 
growth of Ps. phaseoli and seriousl}^ retarded that of Ps. eainpestris., 
but did not prevent it. On the contrary, when the retarding influence 
was overcome growth was greatly stimulated. On the seventh day 
this growth was only about one-flfteenth as much as in the check tube, 
or as on the 23 per cent cane-sugar agar. On the sixteenth day there 
was a marked increase of growth, but there was not one one-hundredth 
as nmch as in the corresponding tube of cane-sugar agar. On the 
thirtieth day the streak was 23 by 6 to 8 ram. On the thirty-seventh 
dav growth had doubled, the streak now being 40 bv 3 to 12 mm. The 
slime dissolved I'eadily in water and consisted largely of chains 50 to 
loo /Hong. In a repetitif)n of this series of experiments, 23 per cent 
grape sugar retarded but did not prevent the growth of ]*s. phaseoli. 
The surface was rubbed with loops from agar cultures, but growth did 
not appear until the fourth day, and then only colony-wise. 

(5) On the 9 per cent (acid) fructose agai' I*x. pliaxeoll refus(>d to 
grow. Ph. ca/rapestris obtained a precarious foothold, but grew oidy 
a little. 

(iS) Addition of 17 or 23 per cent cane sugar did not retard the 
growth of I*s. eawpestrix or ]*s. phaseoli^ at least, not to any notice- 



96 

able extent. On the contrary, within a fewdays growth was enor- 
mously .stimulated. If the volume of growth of 7's. hy<ichitki on the 
17 per cent cane-sugar agar at the end of eight days be reckoned as 1, 
then that of Ps. campestr'iH was 2 or 3 and that of Ph. phaseoli was 3 or 
4. On the 23 per cent cane-sugar agar, on the fourth day, the growth 
of Ps. campestris was five times as much as in the check tube, and that 
of i^s. phiseoli -'vastly better." On the twelfth day the cultures of 
Ps. campestris and Ps. jjhaseoll resembled each other closely in color, 
general appearance, and amount of growth, which latter was ten 
times that in the corresponding tube of Ps. hyacinthl. On the thirty- 
sixth day the slime of Ps. pluiseoU consisted of rods. doul)lets, fours, 
and many chains 50 to 120 }x long. 

(7) The growth of Ps. cainpesfris and Ps. jyhaseoli on the sugar agars 
was smooth, wet-shining, and often abundant enough and thin enough 
to flow like thick sirup on tilting the tubes. That of Ps. hyacinthi 
would never flow and was distinctly areolated, reticulated, wrinkled, 
or shagreened, as already described. 

Sodium Acetatk. 

The stock (1:95) containing this substance was compounded as fol- 
lows : 

Distilled water, 400 c. c. 
Dipotassium phosphate, 0.800 gram. 
Magnesium sulphate, 0.0-40 gram. 
Ammonium phosphate, 0.040 gram. 
Sodium acetate, 2 grams. 

This medium was filled into cotton-plugged test tubes and sterilized 
in the usual way. It was inoculated with Ps. hyacinthi x^vy copiously 
from a young culture on coconut. It was under observation 5 weeks 
at 25° to 30° C, but growth progressed very slowly and was never 
anything more than feeble. At the end of the 5 weeks the fluid 
was still feebly clouded and there was no rim of germs or pellicle, 
but in the fluid on the wall of the tube were several hundred small, 
ragged, whitish flocks and on the bottom there was a pale yellow pre- 
cipitate 5 mm. wide. The growth was not better than in Uschinsky's 
solution. 

Ps. campestris 'also grew feebly in this fluid, and Ps. stcwarti would 
not grow at all (only one test). 

NUTRIENT STARCH JELLY WITH SUGARS, GUMS, AND ALCOHOLS. 

Some comparative tests of these four yellow organisms as to color, 
rate of growth, etc., were made in tubes of slant nutrient, starch jelly 
to which 500 milligrams of special kinds of carbon foods were added — 
e. g., dextrin, lactose, maltose, etc. The growth in these tubes was 
compared with that in tubes of starch jelly to which the sugars, etc., 
were not added. My general conclusions are as follows: 



V>7 



Table V. — Behnrivr i>f I'x. InjariutJil, etc., on. iintrifnt darch jelly imth various carbon foods. 



Substance 


Organisms. 


added. 


Ps. hyacinthi. 


Ps. campestris. 


Ps. phaseoli. 


Ps. stewarti. 








A marked stimu- 
lating effect. 
Growth very copi- 
ous, sirupy and 
with a magnifi- 
cent production 
of the yellow pig- 
ment. 


No increased growth. 










Dextrin ... 


A stimulating effect. 
Bright yellow. 
Growth several 
times as abundant 
as in tlie check tuljes. 






No increased growth. 








Maltose 


Feeble at first, then 
s e V e r a 1 t i m e s as 
much as on check. 
Bright yellow. j 






No .stimulating ef- 






fect. Very fee- 
ble pale-yellow 
growth. 


Galactose.. 


A stimulating effect. 
Several times as 
mucli growth as in 
check. Slime very 
bright yellow. 






Marked stimulating 






effect. As much 
growth or nearly 
as much as on cane 
sugar. 100 times 
as much growth 
as on the glycerine 
jelly. 


Cane sugar 


Copious bright-yellow 
growth. Several 
times a s abundant 
as in check. After 
128 davs the starch 
immediately under 
the bacterial layer 
gave a marked re- 
action with iodine, 
blue and purple. 
Litmus reaction 
feebly acid. 


Copious, smooth, 
wet-shining pale- 
yellow growth. 
Not much more 
abundant a n d 
not so yellow as 
finally in the 
glycerinated jelly. 




Marked .stimulating 




effect. A copious, 
smooth, wet-shin- 
ing, buff-yellow, 
sirupy growth. 


Maiinit 


No stimulating effect. 
Not more growth 
than in the check 
tubes. 






No stimulating ef- 






fect. 


Glycerin... 

* 


Growth feeble for some 
weeks as if retarded, 
color pale. After 128 
dav.s the whole sur- 
face of the .slant (7 
s<|. cm.) was covered 
with a dense growth. 
The color was a uni- 
form dull yellow, a 
little brighter than 
wax yellow. The 
entire .surface was 
shagreen ed. The 
s t !i r c h was not 
iM-owncd. It had 
lifted a little from 
the bottom on which 
was a small amount 
of yellow fluid due 
to the solvent action 
of tlie gl ycerol. 
Neither slime nor 
fluid were alkaline, 
both appeared to Ijc 
neutra when wet, 
and tlie litmus was 
only .slightly acid 
when dry. The 
slinu' WHS not sticky. 
The starch even im- 
mediately under the 
yellow layer reacted 
at once blue: (i r 
purple with iodine. 


Retardation of 
growth, of yellow 
pigment, and of 
diastasic action. 
After 24 days, 
however, a co- 
pious, sirupy 
smooth, wet-shiii- 
ing, rather bright 
yellow growth 
over whoje slant, 
and (uiUtire then 
in marked con- 
trast to I'x. phd!'- 
e oli an d P s . 
stcwarti. 


Retards growth, 
diastasic action, 
and formation of 
yellow pigment 
(only one test). 
After 24 days not 
one n e - h u n - 
dredth as much 
growfh as in the 
check or the lac- 
tose jelly and no 
distinct yellow 
pigmentation. 


No stimulating 
effect, and appar- 
ently a dist net 
retardation. 



21788— No. 28—01 7 



98 

TEMPERATURE EXPl'.RIMENTS. 

Thekjial Dkatii Point. 

Some difficulty was experienced in determining accurately the ther- 
mal death point of Pa. hyacinthi owing to the slight Aariability in 
sensitiveness of individual rods. Considerable trouble was also expe- 
rienced for some time owing to the frequent unaccountable failure of 
the germs to grow in some of the fluid cultures (see Sensitiveness to 
acids). 

Most of these experiments were made in thin-walled test tubes 
16 to IT mm. in diameter, and containing exactly 10 c. c. of fluid 
(usually beef broth) entirely free from any trace of sediment or 
cloudiness. These tubes were inoculated in each case with big loops 
from fluid cultures only a few days old (1 to 11), and great care was 
taken in making the inoculations not to wet the walls of the tube above 
the fluid, and also to keep the tubes upright from flrst to last. The 
exposures were made by plunging the inoculated tubes into a hot- 
water bath nearly to their top, and keeping them in it at the given 
temperature for exactly 10 minutes. They were then removed, and 
either cooled quickly under running water or left to slowly acquire 
the temperature of the room. Duplicate tul)es were always inoccu- 
lated and maintained at the living-room temperatures for comparison. 
On two occasions poured plates were also made, using a large quantity 
of the cultiu-e fluid so as to determine more .precisely the proportion 
of the germs killed by the heating. 

The hot-water bath employed was the Ostwald-Pfeifer, using a very 
sensitive Roux metal-bar thermo-regulator, and a stream of com- 
pressed air for the motive power. The thermometer employed was a 
very sensitive one, belonging to a set made by Max Kaehler and Mar- 
tini, of Berlin, and compared with the standard hydrogen thermome- 
ter of the International Bureau of Weights and Measures, Washington, 
D. C. With this apparatus, wdiich keeps the water uniformly in 
motion, it was easy to maintain approximately constant temperatures 
for short periods. 

The following is a detailed account of these experiments: 

I. December 3: One tube of stock 204 inoculated with a large loop from tube 6 
December 1. This tube was? allowed to stand 1 hour and then plunged for 10 min- 
utes into water at 54.30° C. Cooled at room temperature. Result: Under observa-. 
tion several weeks, but no growth. 

II. December 3: One tube of stock 204 inoculated with a large loop fnjm tube 6 
December 1. This tube was allowed to remain 3 hours at room temperatures and 
then plunged for 10 minutes into water at 49.80° C. Cooled at room temperatures. 
Result: No growth. Tube under observation several weeks. 

III. Decembers, 1896: One tube of stock 204 (1:2 acid beef broth, i. e., no pep- 
tone or alkali added ) inoculated with a large loop from tul)e 6 December 1, which 



99 

was a well-clouded/ 43-huur culture in t^UK-k 204. The germs were allowed to grow 
in the liroth 1 hour, after which the tube was plunged for 10 minutes into water at 
46° C. and then cooled at room temperatures. Eesult: Tube under observation 
several weeks, but no growth. 

Check.— On December o, at the same time as I, II, and III, another tube of stock 
204 was inoculated with a large loop from tube 6, December 1, and left at room tem- 
peratures. Kesult: Growth was retarded, but not prevented. On the eighth day 
the medium w^as still clear, but on the thirteenth day the fluid was faintly clouded 
with a little precipitate and with good rolling clouds on shaking. This broth was 
not titrated, and consequently its grade of acidity was not known. It was feebly 
acid to litmus and contained a small amount of muscle sugar. 

IV. December 8: Two tubes of stock 204, one inoculated from tube «, December 1, 
and the other from tube 7, Deceml)er 1 (a beef-broth culture inoculated with 
descendants of germs isolated from another hyacinth bulb). Each tu})e received a 
large loop of the fluid, and as the cultures were some days older, more germs than 
tubes I, II, III, and their check. After 1 hour both tubes were plunged for 10 min- 
utes into water at 43.25° C, and then cooled at room temperatures. Result: Decem- 
ber 11 l)oth tubes are faintly clouded; December 17, moderately cloudy with rolling 
clouds on shaking and a small amount of yellow precipitate. The germs are not 
killed by 43° C, and are little, if any, retarded, the two check tubes clouding in 
about the same time and manner. 

V. December 8: Two tubes of stock 204, one inoculated from tube 6, December 1, 
and the other from tube 7, December 1. In all respects a duplicate of IV, except 
that the water bath was 44.35° C. The tubes were cooled at room temperatures. 
Result: December 11 both tubes are faintly clouded; December 17, no pellicle, but 
a moderate amount of yellow precipitate and a good many small, roundish zoogloese 
in the top layers of the fluid. These zooglceas diffuse through the fluid on gentle 
shaking. Temperature of 44.35° C. does not kill or much retard growth. These 
tubes were compared with the 2 check tubes mentioned under IV^. 

VI. December 8: Two tubes of stock 204, one inoculated from tube 6, December 1, 
and the other from tube 7, December 1. In all respects like V, except temperature 
of water bath, which was 45.20° C. The tubes were cooled at room temperatures. 
Result: December 11, both tubes perfectly clear. On December 17, when next 
examined, the fluid iu eaih tube was moderately cloudy, wiHi distinct rolling clouds 
on shaking. Cloudiness easily visible without shaking. A little precipitate. Tem- 
perature of 45.20° C. does not kill, but consideralily retards growth, the 2 check 
tubes (those mentioned under IV) being cloudy on December 11 . The germs in tubes 
6 and 7, December 1, were derived (as already stated) from different hyacinth buUjs. 

VII. May 14: Six tubes of stock 217 (cauliflower broth feebly alkaline to neutral 
litmus), each inoculated with a loop from tube 5, May 10 (stock 218, a potato broth 
which came up slowly and was moderately cloudy, with rolling clouds on shaking). 
Four of these tubes were plunged for 10 minutes into water at 45.60° C, and two 
were held as checks. Result: The tubes were under observation for several weeks, 
but all of them, including the two checks, remained sterile. There was no apparent 
reason for the failure of the two checks, since the material used for inoculation was 
living (see VIII), and closely related organisms grew well in this broth, e. g., Ps. 
pliaseoli. 

VIII. On May 14, from two tul)es of litmus neutral beef brotli peptone agar, two 
poured plates were prepared in the following manner: 

(1) One cubic centimeter of the well-clouded potato-broth culture (tube 5, May 



1 It is po88it)le that part of this clouding may have teen due to dead or feeble indi- 
viduals derived from the original inoculation, whicii was probal)ly from a solid 
culture. 



100 

10) was transferred by means of a sterile pipette to lU c c. of fluid agar { cooled to 
41° C. ), and after thorough shaking was poured into a sterile Petri dish. 

(2) The remainder of the culture was then plunged for 10 minutes into water at 
46.05° C. ; it was then cooled at room temperatures for a few minutes and 1 c. c. taken 
out liy means of another sterile pipette, put into another tube of melted agar (10 c. c. 
at 41° C. ), and when thoroughly shaken poured into a second sterile Petri dish. 

These two dishes were then kept at living-room temperatures and compared from 
time to time by turning them bottom u]) under the microscope. Result: May 18 
(1) agar uniformly milky cloudy. Under the microscope innumerable small colonies 
are to be seen. Number of colonies estimated at 8,000 to 10,000 per field (Zeiss 16 
mm. and 12 comp. oc.) (2) This plate was also milky cloudy, but the colonies 
were larger and not nearly so numerous, a1>out 95 per cent liaving l)een destroyed by 
the heat. 

These two plates were kept under observation for a week or two, but with no con- 
flicting results. 

IX. June 3, 1897, six tul)es of stock 245, a beef l)roth made feebly alkaline to 
litmus by means of sodium carbonate, were selected for this experiment. Each was 
inoculated with a loop from tube 4, June 2, a 26-hour culture in stock 245, which was 
not yet distinctly clouded, but became so after a few hours. Four tul)es were heated, 
but not until over an hour after inoculation (room temperature 28° C. ) The tem- 
perature of the bath was unusually variable, ranging from 46.70° to 47.10° C, it being 
most of the time below 47° C. 

Results: (1) Two of the tubes were cooled slowly at room temperature. These 
tubes were examined at intervals of a few days until July 29, but both remained 
clear. 

(2) Two of the tubes were cooled quickly under running water. One of these 
tubes remained clear for 56 days, after which the exjieriment was discontinued. 
The other remained clear until the sixth day. It then became feebly clouded, and 
contained numerous small zoogloepe, most of the germs seeming inclined to pass at 
once into this state, i. e., growth was retarded but not all of the germs were killed. 
June 10, feebly clouded, zooglciw larger, mimerous, ragged. June 14, moderately 
clouded; slight rim on tul)e at level of liquid; the larger zooglwae are distinctly yel- 
low. June 16, well clouded with rolling clouds on shaking. Considerable distinctly 
yellow precipitate. A thin pellicle in shape of a delicate membrane thickly dotted 
with small zooglfcre is present. This membrane sinks on gentle shaking, breaking 
up into ribbons which are fine granular under X6 Zeiss aplanat. June 28, copious 
yellow precipitate. The pseudo-pellicles have all settled. July 6, abundant yellow 
precipitate. Fluid nearly clear. On this date the other three (sterile) tubes were 
reinoculated from this tube, but they remained clear. 

(3) Two of the tubes were kept as checks. One of them became contaminated 
with a white organism growing best on the bottom of the tube (Oospora?) . The other 
remained clear imtil after the third day. On the fifth day it was distinctly but 
feebly clouded, and the surface layers contained small zoogloese which streamed 
down cloudily on gentle shaking. June 9, clouded more than yesterday, but not 
heavily so. June 10, well clouded with considerable yellow precipitate. June 14, 
a pellicle consisting of yellowish more or less united zoogl(ra\ June 16, well clouded 
with rolling clouds on shaking. No new pellicle. The broken one (shaken down 
on the 14th) has not gone to pieces, but lies on the bottom with hundreds of tiny 
zooglcpfe embedded in it very regularly. June 28, a copious yellow precipitate. 
July 6, fluid nearly clear, i. e., becoming exhausted of nourishment; otherwise as 
before. July 29, washed out; precipitate yellow. 

X. On June 3 three tubes of stock 244b (+20 gelatin) were converted into 3 
poured plates as follows: 

(1) One cul>ic centimeter of the cloudy Huitl from tulie 4, June 2 (see IX), was 



101 

transferred to 10 c. c. of srolatiii at .'!0° ('., shaken, and ponred into a sterile Petri 
dish to form the clieck plate. 

(2) Tlie remainder of the cnlture (approximately 9 c. c.) was then plunged for 10 
minutes into water at 4().r>0° to 46.60° C, and another 1 c. c. immediately pipetted 
out into another tiihe of 10 c. c. of gelatin at 30° C, shaken, and poured into a 
second Petri dish. 

(3) The culture was then allowed to cool to room temperatures after which 1 c. c. 
was pipetted into another 10 c. c. of gelatin at 30° C, shaken and poured into a 
third Petri dish. 

These 3 dishes were then put into the cool box, where they were kept at 12° to 16° 
C, and examined and compared from time to time in the same way as the dishes of 
agar. 

Results: (1) Colonies to the number of 2,000 to 3,000 per field (Zeiss 16 mm. and 
12 comp. ocular) appeared in this dish. (2) More than 80 per cent of the germs 
were destroyed by the heat, i. e., there were only 200 to 600 colonies per field in this 
dish. (3) About 400 colonies per field appeared in this plate. 

The culture from which these 3 plates were inoculated was made with a single loop 
from a broth culture 1 1 days old and this fact, together with its own age (28 hours at 
24° to 28° C), precludes the idea that spores played any part in the results obtained. 

XI. February 3, 1898: Six tubes of alkaline beef broth, stock 286b (stock 286 con- 
sisted of the broth from 1,000 grams of minced lean beef covered with 1,500 c. c. 
distilled water and left in the ice box 24 hours. The fluid was finally made up to 
2,000 c. c, titrated, and divided into four ecjual parts. Stock 286b received enough 

2N 

^ NaOH to render it exactly neutral to phenolphthalein, i. e., strongly alkaline to 

neutral litmus paper). These tubes were of Weber's resistant glass, 169 by 17 mm., 
and very thin walled. Each received exactly 10 c. c. of the l)roth, in which, from 
previous tests, the germ was known to grow readily, even when added in very small 
'quantities. Each of these 6 tubes was inoculated with a drop of fluid from tube 1, 
Jan. 29, a l)eef broth which was nicely clouded with good rolling clouds on shaking. 
This broth had been clouded about 55 hours, but showed as yet very little precipitate 
and no pellicle or zoogloea;. As much fluid was put into each tube as could be lifted 
out on a medium sized (2 mm.) loop and 5 or 6 cm. of wire above it, i. e., an enor- 
mous number of germs, as microscopic examination showed. About 15 or 20 
minutes after inoculation 4 of the tubes were plunged into the hot water, while the 
other 2 were held as checks. The exposed tubes were \mt well down into the bath 
so that the surface of the broth was 5 to 8 cm. below the surface of the water, which 
was in constant motion. The exposure was exactly 10 minutes. On removal, 2 of 
the tul)es were cooled innnediately umler flowing water, while the other 2 were 
allowed to cool gradually at room temperature (23° C. ). All were then screened 
from the diffused light of the room and set away at room temjieratures which varied 
from 15° to 25° ('. The temperature of the water l)ath at the beginning was 47.80° 
C, falling slowly to 47.58° C. at the end. During the middle 8 minutes the range of 
temperature was from 47.70° C. to 47.60° ('. These tubes were under observation 
33 days. 

Results: (1) Checks. Both tubes clouded inside of 48 hours and passed through 
a normal course of growth. (2) Cooled quickly. Both tubes remained perfectly 
clear. (3) Cooled slowly. Both tubes remained perfectly clear. 

XII. February 3, 1898: This experiment was in all respects a duplicate of the 
preceding, except that the water was a trifle cooler and that after iin)culation the 
tubes were allowed to stand one-half hour before plunging. The temperature of the 
water waa 47.45° C. at the beginning and 47.17° C. at the close. After one minute 
the tem|)erature of the bath fell to 47.30° C. and during the next ^ minutes it gradu- 
ally fell to 47.20°. During the remaining 3^ minutes the temperature fluctuated 
between 47.16° C. and 47.18° C, being at the latter point most of the time. 



102 

KowiiUh: (1) CheclcH. I'.olli lulxs clinnlcd inside of 4S liniirs and 'Icveloped 
iiuniially. (2) Coolcrl i|iii<kly. Butli tul)cs rcmairKMl })erl'ectly clear till the end of 
the experiment (.33 davH). (3) (V)olc(l sluwly. Both tubes remained clear until the 
ninth day. Then one i)f them l)eciime very feehly clomled and jiradnally pasned 
throuKli the same chan^ieH as the check fnhes, hut never caught up with tin' latter. 
Tlic (itlicr tulic cnntiinicil clear till the cikI of the ex prrinicnt. 

As !i result, <tl' tlicsc cxpcriiiicnts we may conclude that exposure of 
7V hyactntJii for in luiiuites to a temperature of 43*^ C. does not 
apprecia])ly retard j^rowth; \\ retards u-rowth slinlitly; 45'^ retards 
considera])ly; 40' to 4(5.50 destroys the oreater part of the or<ran- 
isms; 47.17 to 47.45' (mostly 47.20 to 47.80 ) desti-oys ahiiost all; 
47. ns to 47.SO' (mostly 47.r>0 to 47.70' ) destroys all. 

The thermal death point, therefore, under the exact conditions 
named, may l)e recorded as ai)proximat«dy 47.60' , Imt a majority of 
the rods are killed at 46.50° C. 

Pro})al)ly some of the rods are destnn'ed hy lo minutes' exposure 
to temperatures as low as 45 ' or 45.50°. Exposures lor nuu-h longer 
|)eriods to temperatures a few degrees lower, e. g., 7 days at 40° C, 
liave the same effect, as may be seen from what follows. 

Tlu^ thermal death ])oint of Px. Kf(^mrt/ in +15 ))eef l)ouillon is 
ai)proximately 53° C. In Uschinsky's solution it is a little higher. 

The thermal death point of Z^-. phaxeoJl is approximately 4H.50°, 
and that of 1\. campcKiriK^ is 51-50 . 

Maximcm 'i'i;Mi>i;nA riKic i-oit < titowTii. 

The maxiimun temi)erature at which V's. Injucivtlti will grow in 
favora))h! media is 34' to 35° C, the exact temperature limit varying 
somewhat with the medium used and with the heat resistant power of 
individual rotls. This conclusion rests on the following experiments, 
which were made in a R()hr])cck thermostat, covered with thick hair- 
cloth and provided with a lai'ge water reservoir, so that the culture 
chamber is not ([uickly sensitive to changes in gas ])ressure or in the 
temperature of the room. 

(1) In stock 244c (0 jielatin), kej)t in the thermostat at 40° C, there was no 
•jfrowth whatever, and noni' ai)peare(l when this tube was removed from the thermo- 
stat at the end of 7 days and kept at room tem])eratnres for an additional 3S days. 
This tube was inoculated with a very large loop from a beef-bidth culture, which 
had been cloudy for (i days. In a second tube of this gelatin, in(tculated from the 
same culture at the same time and in the same manner, but kept throughout at 
room temperatures of 24° to 34° C. (mostly 25° to 29°), the organism developed 
normally, clouding the fluid in 24 hours. 

(2) Three |)()tato cylinders (stock 24(>) were inoculated at the same time and from 
the same culture as the 2 tubes of gelatin. One of the.se was i)ut into the thermostat 
at 40° C. and the other 2 were kept at room temi)eratures. 

Result: In each of the 2 check tubes the organism developed normally, the first 
distinct sign of yellow growth being visible in about 47 hours. No trace of growth 
appeared in the tube which was put into the thermostat, although a very large loop of 



103 

broth wa8 used in making the inoculation, and there was plenty of water in the bot- 
tom of the tube. After 7 days this tube was removed from the thermostat and kept 
in the dark at room temperatures for 38 days, but no growth ensued. 

(8) Three well-plugged tubes of 1:2 moderately litmus alkaline beef broth (stock 
245) were inoculated at the same time from the same tube, and in the same way. 
Two of these were put into tlie thermcjstat at 40=' C. and the other was kept at room 
temperatures. 

Result: The check tul)e clouded on the fourth day and i)assed through a normal 
course of develoimient. The tubes in the thermostat remained perfectly clear until 
the end of the experiment (45 days). 

(4) Three tubes of cauliflower broth (stock 217 ), whicli l)y long standing had dried 
out one-fifth (2c.c.), were also inoculated at the same time from the same culture 
and in the same way. Two of these tubes were kept at room temperatures and the 
third was put into the thermostat at 40° C. 

Result: One of the check tubes clouded on the third day, the other some time 
between the fourth and seventh day. Both developed a yellow pellicle and threw 
down a yellow precipitate. The tul)e in the thermostat was imder observation 45 
days, but there was no growth. 

(5) Three tubes of 1:2 acid beef broth (stock 204) were each inoculated with a 
large loop from a beef -broth culture of Ps. hyaciMhl 7 days old. This culture, which 
was moderately cloudy, showed many small zoogloeje floating in the fluid, and on 
the bottom a small amount of decidedly yellow precipitate. Two of these tubes 
were put into the thermostat at 36° to 38° C. and the third was kept at room tem- 
peratures (mostly 21°). 

Result: On the third day the check tube became feebly clouded and contained 
many tiny zoogkwe. On the eleventh day this tube was moderately cloudy, showed 
a yellow precipitate, and bore on the wall of the tube at the surface of the fluid a 
yellow rim of loosely adhering zooglo^a?. An agar culture inoculated from the same 
tube at the same time and kept at room temperatures also developed normally. 
The tubes in the thermostat remained free from bacterial growth as long as the 
experiment continued (22 days). 

(6) Three tubes of resistant glass, each containing 10 c. c. of strongly alkaline beef 
broth (stock 286b, neutral to phenolphthalein), in which Px. Iti/aciritlti was known to 
grow well, were each inoculated with a loop from a clouded tube of alkaline beef 
broth days old. After remaining for an hour at room temperatures, 2 of these 
tubes were put into the thermostat and kept at 35° to 36.35° C. during the first 5 days, 
then at 32° to 33.50° for 24 hours, and afterwards at 34. 15° to 35.35°. The third tube 
was kept m the dark at rtjom temperatures ranging from 18° to 23° C, except on one 
day when the room temperature fell to 8° C. Each of the tubes put into the thermo- 
stat received a large loop of the cloudy l)roth; the tube left at room temperatures 
received a smaller loo]i of this liroth, i. e., not one-fourth as many germs. 

Result: In 43 liours the (-heck tube was distinctly clouded. On the fourth day it 
was well cloude<l, free from zooglcea;, and showed some yellow precipitate. The 
other 2 tubes remained clear as long as they were left in the tliermostat. One was 
removed on the thirteenth day and left for 24 days at room temperatures (mostly 
22° C), but no growth ensued. Tlie other was removed on the sixth day and left at 
room temperatures 31 days, but no growth ensued. At the close of the experiment 
the tubes still contained 8 c. c. of ])roth, i. e., the concentration was not beyond what 
this organism bears ri'adily. 

(7) Tliree cylinders of sugar ))eet (stock 292) were inoculated at the same time 
and from the same tube as the preceding, each tube rec-eiving a large loop of the 
cloudy fluid. Two of these tubes were put into the tliermostat along with the beef 
broth (6), and tlie third was kept at room temperatures. 

Result: The che<k tube showed no growth at the end of the fourth day, i. e., there 



104 

was some retardation. On tlie sixtli <lay, when next exaniine<l, there was a ilistinct 
yellow growth over a large part of the cylinder. On the eightli day this growth was 
bright yellow and copious. The development of this culture was nurmal, and con- 
tinued for a month or niore. The 2 tubes put into tlie thermostat remained free 
from ])acterial growtli. Both were taken out on the thirteenth day and left at room 
temperatures (19° to 26° C. ) for 54 days, l)Ut there was never any growth. 

(8) Four well-plugged tubes of resistant glass, containing 10 c. c. of strongly alka- 
line beef broth (stock 286b), which had evaporated to 8 c. c. by long standing, were 
each inoculated with a large loop from a Ijeef-ljroth culture of I's. liiiitchdli'i 48 hours 
old, which liad been inoculated copiously from a solid culture and was cloudy from 
growth. Two of these tubes were kept in the dark at room temperatures of 20° to 
25° C. The other 2 were jtut into the thermostat at 33.35° to 35.58° C. (mostly 34.32° 
to 34.55°) during the first 8 days, and after that at 32.45° to 35.55°. 

Result: The 2 check tubes clouded in 48 hours and developed normally. The other 
2 tubes remained clear as long as they M'ere kept in the thermostat — 37 days for one 
and 13 days for the other. The latter was removed on the thirteenth day and kept 
at room temperatures for 24 days, l)ut no growth ensued. The germs were dead, 
however, in each tulje considerably in advance of the thirteenth day, for 2 tubes of 
the same beef broth which were inoculated therefrom on the eighth day, using large 
loops, and left in the dark at room temperatures, remaine<l entirely free from growth 
as long as the experiment continued (29 days). 

(9) Two cylinders cut from a yellow turnip and steamed in the usual amount of 
water were inoculated at the same time, from the same cultuie, and in the same 
copious manner as the preceding. One of these was put into the thermostat and the 
other was kept at room tcmijcraturcs. 

Result: The check tube showed a distinct yellow growth on the third day. On 
the fifth day this growth was copious and typical for Ps. hyacinth). The tube in the 
thermostat showed no growth on the fifth day and was then reinoculated with a large 
loop of yellow slime from the check tube. The tube was then shaken until the slime 
was washed over the cylinder and dissolveil in the fluid, and the yellow color invis- 
ible. The tube was tlien put back into tlie thermostat. In 26 hours there was a 
slight yellow growth on the upper part of tlie cylinder (temperature 34.45°, falling 
slowly to 33.35° C. ). Two days later there was, ajiparently, no increase of growth 
(temperature 34.53° a. m., 34.15° p. m., 34.32° a. m.), and iiot one one-hundredth 
part as much growth as in a tube inoculated at the same time f(jr ciomparison. On 
the eighth day (temperatures 34.40° to 35.55° C.) growth was very scanty and the 
color scarcely visible. The amount of growth at this time was not one three- 
hundredth as much as in the check tube held at room temperatures. On tlie twelfth 
day after this reinoculation growth had increased a little, but was still very feeble 
and certainly not one one-hundred and fiftieth as much as the same culture would 
have given at room temperatures. During these last 4 days the thermo.stat was 
consideralily cooler, the temperature of the culture chamber ranging from 32.45° 
to 34.45° C, and being most of the time below 34°. After 49 days in the thermostat 
a tube of alkaline beef l^roth was inoculated very copiously from this tube and left at 
room temperatures 27 days, but no growth ensued, i. e., tlie Aegetati\-e rods were 
dead and no spores were present. 

(10) Two cylinders of steamed sugar beet were inoculated at the same time, from 
the same culture, and in the same manner as in the two jtreceding experiments. 
One of these tubes was put into the thermostat and the other was held at room tem- 
peratures. 

Result: On the fifth day there was no visible growth in either tube and both were 
reinoculated very copiously with the solid slime from a turnip culture 5 days old 
(the check of series 9). The tube which came from the thermostat was shaken thor- 
oughly before replacing, so that if there were any subsequent growth it might not be 



105 

confused with any uudisMolved slime uHcd in making tlic inoculafinn. At the end of 
26 hours there was a slight growth on the e>'linder in eaeh tube. On the third day, 
in the thermostat (temperatures 34.45° p. m., 34..35° a. m., 38.35° p. m., 34.53° a. m., 
34.15° p. m., 34.32° a. m.) the germs covered 2 s(j. cm. on one side of the cylinder. 
This growth was jjlainly yellow but extremely thin. On tlie fifth day (temperatures 
34.32° p. m., 35° a. m., 34.40° p. m., 34.85° a. m.) there seemed to be a slight 
increase in growth. This growth was very thin, distinctly yellow, not smooth, and 
rather dry, i. e., not wet-shining. In the check tube there was from 10 to 20 times 
as much growth, but not as much growth as there should have been, owing to the 
fact that the check cylinder was rather dry. On the eighth daj^ (temperatiires 34.85° 
a.m., 34.55° p.m., 35.55° a.m., 35.45° p.m., 34.83° a.m., 34.65° p.m., 34.95° a.m.) 
there was some increase, the growth being distinctly yellow, but too thin to hide 
minute irregularities of the substratum. The ^'olume of growth at this time was not 
one-fiftieth that in the check tuVje. Examined microscopically, this growth con- 
sisted of zoogloete, short rods and long rods. The short rods were single, in doubles, 
or in fours; the long rods were slender threads, 10 to 20 or more times the length of 
an ordinary rod. These threads were numerous and their segments were not well 
defined. No involution forms were observed or anybodies suggestive of spores. On 
the twelfth day (temperatures .34.05° a. m., 33.35° p. m., 34.45° a. m., 33.35° p. m., 

32.75° a. m., 32.45° p. m., a. m. ) the growth was meager, thin, dull yellow, and 

its surface was shagreened. There was no yellow slime in the water, but the germs 
on the cylinder out of the water appeared as if still growing, although very slowly. 
After 49 days in the thermostat a large loop of slime from this tujje was removed and 
put into alkaline beef broth. This tube was kept at room temperatures for 27 days, 
but n(j gro\\-th ensued. 

(11) This experiment was undertaken to see ij cultures started at room tempera- 
tures would not do better when put into the thermostat than those which had been 
inserted soon after inoculation. For this purpose I selected a tube of alkaline beef 
broth, which had been kept as a check on series No. S, and a tube of yellow turnip, 
kept as a check on series No. 9. The turnip culture was put into the thermostat on 
the fifth day, at which time there was a coinous, yellow, wet-shining, homogeneous- 
looking growth covering most of that part of the cylinder out of the water. The tube 
of beef broth was put in on the eighth day, at which time the fluid was moderately 
cloudy and had thrown down a little yellow precipitate, but had not yet developed 
any pellicle, rim of germs, or zooglceae. The temperatures were 34.15° to 35.55° dur- 
ing the first 9 days (once as low as 33.35°) and then 32.45° to 34.45° C. There was 
no exact check tube for the turnip, but a transfer was made from it into another tube 
of the same medium; for comparison witli the beef l)roth the other check tube of 
series No. 8 was used. 

Result: (a) The beef broth in the thermostat at once fell behind the check tube 
in growth. On the fifth day the clouding appeared to be feebler than on the start 
and the trifling precipitate had increased proportionately to the decrease in clouding, 
but scarcely more. The check tulje was distinctly cloudier. On the ninth day there 
was no increase of precipitate. On the twenty-ninth day there was no pellicle, no rim 
of germs, no zoogloeae, and not more precipitate than on the fifth day, i. e., there 
appeared to have been no growth whatever during the whole time of the exposure. 
On this date the check tube was uniformly clouded, showed a yellow rim, and had 
thrown down a yellow precijjitate 12 mm. Ijroad and 2 mm. deep. On the twenty- 
ninth day a large loop of fluid was taken from the tube in the thermostat and put 
into a sterile tube of the same l)eef broth. This tube was under observation 17 days, 
in conditions very well suited for growth, ])ut no growth ensued. At the end of 46 
days in the thermostat this experiment was repeated, inoculating copiously into 
alkaline beef broth diluted with distilled water. The tube was kept at room tem- 
peratures and watched for 27 days, but no growth ensued, i. e., no spores were pres- 



]06 

ent. (h) On thf fiftli day in the thermostat the slime on the turnip cylinder was 
still \vet-.«hinincr, but it ^va^; not as homogeneous looking, being uniformly mottled 
lighter and darker yellow. On the eighth day the culture was less vigorous and the 
substratum had browned slightly. The slime was now examined microscopically 
for several liours. It consisted of the ordinary short rods and of slender threads 
which were of the same diameter as the rods but were often 50 times as long. These 
threads were numerous. No involution forms were observed injr any bodies resem- 
bling spores. On the tw'elfth day the culture was in a much worse condition. Growth 
had ceased and the slime out of the water had so much dried out that the substratum 
under it was now visiljle. Nineteen days after this date the turnij) cylinder which 
had been inoculated froju this tube and kept at room temijeratures was still covered 
with a thick, smooth, wet-shining, homogeneous-looking, pale yellow layer of slime, 
entirely hiding the substratum. The fluid in the bottom of the tube was also grown 
full of the slime, which was not the case with the culture in the thermostat. After 
49 days in the thermostat a large loop from this tube was put into alkaline beef 
broth and watched at room temperatures for 27 days, but no growth ensued. 

(12) Two steamed cylinders of carrot (stock 290), standing in several cubic centi- 
meters of distilled water in tubes of resistant glass, were each inoculated with a large 
loop of the yellow slime of Ps. hi/dcinlhi from recent growths in a turnip culture 5 
days old. These tubes were then shaken until the slime was dissolved in the water 
and washed over the cylinder. One of the tubes was put into the thermostat at 
33.35° to 35.45° C. (mostly 34.35° to 35°) and the other was held at room temperatures. 

Result: On the thir<l day the check tulte showed a plentiful yellow growth, cover- 
ing nearly all of one side of the long cylinder. On the fifth day this growth was 
dense enough to hide the orange color of the substratum. The tube in the thermostat, 
on the eighth day, showed no growth whatever, although it still held 2 c. c. of water 
and was consequently moist. This tuloe was now removed to room temperatures of 
19° to 25° C. On the fourth day thereafter a copious, smooth, wet-shining, homo- 
geneous-looking, bright yellow growth, dense enough tri liide the substratum, covered 
about 3 sq. cm. of the inoculated cylinder. 

(13) Two cylinders from a yellow, flat-bottomed turnip, prepared in the same way 
as the carrot, were inoculated at the same time as the latter and from the same culture, 
each tube receiving a large loop of the yellow slime. These tubes were then shaken 
until the slime was dissolved in the water and spread over the cylinder. One of the 
tubes was held at room temperatures and the other was put into the thermostat. 
The tube in the thermostat contained several cubic centimeters of water; the check 
tul)e contained only a small amount of water. 

Result: On the third day, in the dieck tube, there was a copious, smooth, wet- 
shining, yellow growth over nearly the entire cylinder. On the fifth day this growth 
had become more abundant, covering the whole cylinder and flllihg up the small 
amount of fluid in the bottom of the tube. The other tube was left in the thermostat 
8 days at 33..35° to 35.55° (mostly 34.35° to 35°), during which time no growth was 
visible either to the naked eye or with a Zeiss X 6 aplanat. The tube was now 
removed to room temperatures of 20° to 25° C. On the fourth day after this removal 
two-thirds of the cylinder (all out of the water) was covered with a copious, yellow, 
smooth, wet-shining, homogeneous-looking bacterial layer, which developed nor- 
mally for Ps. hyacinthi. 

(14) Four tubes of 1: 2 acid beef broth (stock 286a, acidity + 25), originally hold- 
ing exactly 10 c. c, but dried out about one-fifth by long standing and consequently 
more acid than the original stock, were each inoculated with two large loops from 
an alkaline beef broth culture of Ps. lujacinthi 10 days old. This culture was uni- 
formly clouded, and showed considerable yellow precipitate, but there were no 
zoogloea? and the rim of germs was only commencing to form, i. e., the fluid was 
crowded full of living germs and in excellent condition for use. Two of the tubes 



107 

inoculated therefrom were get away in the dark at room tt'iii|ieratures of 19° to 25° 
C. (mostly 21° to 23°). The other two were j.ut into thr thcrnioi-tat at 34.o5° to 
35.55° for the first 4 days and then at 32.45° to 34.45° C. 

Result: The check tuhes were feebly clouded on the tliird day. They were first 
examined at tlie end of 72 hours, and probably clouding could not have been detected 
more than 6 or S hours earlier. These two cultures passed through a normal devel- 
opment. The other tubes were left in the thermostat 27 days, during all of which 
time they remained perfectly clear. On the twenty-seventh day both were removed 
to room temperatures and watched for 6 weeks, Init they never clouded. When 
removed from the thermostat each tube still contained about r).5 c. c. of fluid. 

The following- inferences respecting /*s. hf/actnf/u' appeiir to ])e war- 
ranted hv these experiments: 

(a) The organism will not grow on any medium at-iC^ C, and after 7 
days exposure to this temperature it will not grow at any temperature. 
Prol)ably a much shorter exposure to 40"^ C. would kill it. 

(])) The organism will not grow in un neutralized (acid) beef broth 
at W' to 38° C, and consequently it is not likely that it will prove 
pathogenic to warm-])looded animals. 

(c) The organism will not grow in strongl}^ alkaline beef broth at 
35 to 36.35'^ C, and after 6 days' exposure to this temperature it 
will not grow at any temperature. 

(d) The organism will not grow on sugar-beet cylinders at 3.5° to 
36.3.5° C, and after 13 days' exposure to this temperature will not 
develop at any temperature. 

(e) The organism will not grow in strongly alkaline beef broth at 
31:. 15° to 35.58° C, and after 8 days' exposure to this temperature it 
will not grow at an}^ temperature. 

(f) When inoculated ver}' copiousl}' from a young solid culture, the 
organism grew scantily on yellow turnip at 33.35° to 34.1:5° C. 

(g) When inoculated very copiously from a young solid culture, 
the organism grew very feebly on sugar l)eet at 34.15° to 35^ C. 

(h) Growth already well under wa}^ in strongly alkaline beef broth 
and on yellow turnip was stopped at 34.15° to 35.55° C. 

(i) In 8 days the organism made no visible growth on steamed carrot 
at 33.35^ to 35.45° C, but all of the germs were not killed. 

(k) In 8 days the organism made no visible growth on yellow turnip 
at 33.35° to 35.55° C, but all of the germs were not killed. 

(1) In 27 days the organism made no growth in unneutralized (acid) 
l)eef broth at 34.55° to 35.55° C, and all were dead before the twenty- 
seventh day. 

/^s. stewarti refused to grow at 40° C, in UschinskA^'s solution and 
in strongly alkaline beef broth (0 of Fuller's scale). It grows in the 
thermostat at 36° to 37° C, on most media, but not so well as at room 
temperatures of 24° to 25° C. Ps. campestris did not grow at 40° C. , 
and grew not at all or very feebly at 37° to 38° C. — i. e., about as Ps. 
hyacinthi grows at 34° to 35° C. 



108 



C>i>Ti>n>r Temi-khatihk ii>k (iRowni. 



No special experiments have been instituted to determine at what 
temperature growth of ]%. hyacinth! is most I'apid. })ut from a careful 
collation of the records of several hundred cultures made during- the 
past four years and kept at room temperatures — i. e., of all cultures 
which were examined frequently enough during the first few days of 
growth, and for which the necessar}'^ temperature records were set 
down — I find that, on good media, growth was slow at lO*^ to 12^ C, 
moderate at 18° to 25° C, and fast (for this organism) at 28° to 30° C. 
These cultures were instituted at all seasons of the 3'ear, and some- 
times for several days together the room temperature would be nearl}^ 
stationary — e. g., at 18°, 25°, or 30° C. In a few instances I have thus 
been able to compare at difterent temperatures the rate of growth 
when the inoculations were made with the same amount of material 
taken from cultures of the same age and kind 

Using these records, therefore, as a basis for judgment, the opti- 
mum temperature for growth ma}^ be placed at 28° to 30° C. 

Minimum TKMPEKATtTRE fok Growth. 

On very favorable media this is believed to be about 4° C. for Ps. 
hyacinth). Only four sets of experiments have been made. (1) On a 
sugar beet cylinder inoculated copiously with bright yellow slime from 
a starch jelly culture 8 days old and kept in the ice chest at 1()° to 
12° C. (temperature possibly at times as low as 7° or 8° C, but never 
lower) no visible growth appeared in 12 days. The tube was now 
removed to room temperatures. Five da3^s afterwards there was a dis- 
tinct yellow growth coA^ering more than 2 square centiiuetei-s of the 
surface. 

(2) A tube of unneutralized 1:2 beef broth (stock 204), inoculated 
with a large loop from a well-clouded beef broth culture 7 days old 
and put into the ice chest at 10° to 12° C, was clouded verv feebly at 
the close of the fifth day. A check tube at 21° C. clouded feebly in 
67 hours. 

(3) Two freshly prepared cjdinders of coconut, standing in test 
tubes in an abundance of distilled water, were each inoculated with 
approximatel}^ 1 c. mm. of 3'ellow slime from a coconut culture 4 days 
old. These tubes were put into the ice chest. In 42 hours there was 
a slight but distinct growth in each tube, the tempcnniture, however, 
had been higher than was anticipated — i. e. , 10° to 15° C. These tubes 
were now shaken for 10 minutes — i. e., until all trace of the yellow 
growth was washed off and dissolved in the fluid. They were then 
put back into the chest with a larger quantity of ice. On June 2, 4 
p. m. (after 54 hours), there was a slight growth in each tube, although 
the temperature had remained under 8° C. On June 3, 9 a. m. (tern- 



,109 

peraturo 8.2^ C), there had been some further growth. On June 4, 9 
a. m. (temperature 8.5° C), there was a distinct increase of growth 
over what was present 24 hours earlier. One of the two tubes was 
now removed to room temperatures of 25° to 26° C. During the next 
2(5 hours the growth in this tube doul)led. During the same period 
there was a slight growth in the other tube (temperature 8.5° C). 
At this time, in this tube, a bright yellow growth covered more than 
1 sq. cm. of the surface where 5 days before (after the shaking) no 
growth whatever was visible. All of this growth took place ]>etween 
7.4- and 9° C, the temperature most of the time during the 5 days 
ranging between 7.5° and 8.5° C. 

(4) Four tubes of strongly alkaline beef broth (stock 382 neutral to 
phenolphthalein) were each inoculated with a 3 mm. loop from a well- 
clouded beef broth culture 3 days old. One of these tubes was held 
at room temperatures of 20° to 25° C. This culture was moderately 
clouded on the third day and passed through a normal growth. The 
other 3 tubes were placed in the ice chest for 18 days at 2.8° to 4.5° C. 
(mostly 3° to 4° C), during the whole of which time they remained 
perfectly clear. On then removing them to room temperatures they 
clouded in 16 hours at 21°-23° C. The rapidity with which they 
clouded when removed from the ice box suggests that the bacteria 
grew slightly at times while exposed to the low temperature. 

The mininumi temperature of Ps. campestris is not known. It lies 
below 7° C. The minimum temperature of Ps. steioartl is not known 
exactly, but it is believed to be a degree or two higher than that of 
Ps. hyacinthi for the following reason: Tubes of Ps. stewartl were 
exposed in the ice l)ox at 2.8° to 4.5° C, along with those of the 
hyacinth germ. There was no clouding in 18 days, and on removing 
to room tempcrtitures the tubes were not clouded until the third or 
fourth day, and then only feebly. The check tubes clouded on the 
second and third days. The fluids used were Uschinsky's solution and 
an alkaline l)eef broth (stock 382). Each tube was inoculated with 
one 3-millimeter loop from a young fluid culture (3 days old). The 
date of clouding on removal indicates clearly that, contrary to the case 
of Ps. hijaelnthi^ there had >)een no growth whatever during the 18 
da3^s' sojourn of the tubes in the ice chest. 

FORMATION OF ACIDS. 

With exception of the production of a small amount of acid from 
ethyl alcohol (probably acetic acid), the formation of acids t)y Ps. 
hyacinthi is rather oliscure, in spite of all the attention I have given 
to it. At times, especially when small cpiantities of the carbohydrate 
were used, no acid was detected from the growth of this organism in 
the presence of sugars. Even when large quantities of the various 
sugars were used there was no promj)t change from alkaline or neutral 



110 

to acid. After 8ome week.s, however, many of these cultures changed 
from alkaline to neutral, and others became decidedly acid, and the 
acidity increased on concentration by Vjoiling rather than diminished. 
It would seem, therefore, that a small quantity of some non-volatile 
acid is formed by this organism from a variety of substrata, but that 
the formation of this acid is in no way associated with facultative 
anaerobism or with the production of gas. 

The other yelloAV organisms, so far as tested, behaved in the same 
wa}' as Ps. liyoAimtM^ so far as relates to the slow development of a 
non-volatile acid in the presence of certain sugars and of certain vege- 
table substances rich in sugars. 

FOKMATION OF AT.KALIES. 

Feebly acid or neutral culture media of various kinds were finally 
rendered alkaline by 7^s-. /uj<icl)it]ii., but not rapidh' so, and all the tests 
instituted lead me to the conclusion that this organism is a relativelv 
feeble alkali producer. This alkali is volatile, and a part of it, at least, 
is undoubtedh" aimnonia. Neutral or acid reactions were observed in 
the following old and very old cultures: Carrot, sugar beet, sweet 
potato, 3'ellow globe turnip, grape sugar agar, cane sugar agar, nutrient 
starch jelh" with cane sugar, nutrient starch jelly with glycerin. The 
following culture media became and remained alkaline: Potato, coco- 
nut, ordinary nutrient agar, salted peptone water, milk, milk with 
grape sugar, milk Avith methyl alcohol, milk with gh'cerin, hj^acinth 
broth. 

The results obtained by special tests are givein under the following 
heads : 

KosoLic Acid Test. 

The action of I*s. InjaclntJil on rosolic acid was tested in Diuihaurs 
solution. To each 100 c. c. of this salted peptone water was added 1 
c. c. of a solution made of 0.5 gram rosolic acid; 20 c. c. distilled 
water; 80 c. c. absolute alcohol. The alkali in the peptone (Witte's) 
made this culture medium too red, and the fault was remedied b}' 
adding to each 90 c. c. of the solution 6 drops of V HCl, which ren- 
dered the medium yellowish and suitable for the experiment. The 
results obtained with this organism and with others used for compari- 
son are given in the following table: 



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113 

Acid Fuchsix Test. 

The action of Ps. hyachithi on acid fuchsin was tested in peptone 
water. The culture medium was prepared as follows: 

200 c. f. distilled water. 

2 gm. Witte's peptonum siccum. 

4 c. c. aeid fuchsin water. 

2N 
10 drops -, HCl (to counteract the alkalinity of the peptone). 

The acid fuchsin water consisted of 150 mg. of Griibler's Fuchsin 
S. (after Weigert) dissolved in 30 c. c. of distilled water. 

The tubes each contained 10 c. c, of the rose-red fluid. The}^ were 
inoculated on March 21. Tubes 1, 2, and 3 were inoculated from fluid 
cultures; tubes 1', 2', and 3' were inoculated from solid cultures. The 
results obtained with Ps. hyacinthi (tubes 1 and 1'), Ps. canipestris 
(tubes 2 and 2'), Ps. stmnarti (tubes 3 and 3'), B. j^yoc. perlcarditidis 
(tube 1), B. coll (tube 5), B. amylowms (tube 6), and B. carotovorus 
(tubes T to 10) are summarized below: 

March 24- — Slight variations in color, l)ut each tube paler than the check tubes. 

March -27. — Nos. 1', 2, 2', 3', 4, and 5 are much alike in color. They have faded 
considerably; i. e., they are now rose color. Nos. 1, 3, and 6 are deeper red. _ None 
are colorless, but all except 7-10 are paler than on the twenty-fourth. 

March 30. — There has been a marked loss of color in 1, 1^, 2, 2', 4, and 5, and the 
fluids in these tubes are now only pale pink. In 3, 3' and 6 there has been only a 
moderate fading. 

Aprils. — About one-tenth of the color is left in 1 and V; i.e., 1 c. c. of the red 
fluid from a check tube diluted with 9 c. c. of water gives a color a trifle deeper than 
that in these tubes. Only one-twelfth to one-fifteenth of the color remains in 2 and 
2'. In 3 about one-fifth of the color remains, in 3^ about one-eighth, in 4 about 
one-tenth, in 5 about one-ninth, in 6 about one-seventh. In 7-10 there is no fading. 

April 11. — The cultures still fall into three groups, i. e. : (a) Those in which nearly 
all of the color has disappeared, viz, P.s. hyacinthi, Ps. campcstri.'^, and B. pi/oc. peri- 
carditidia. (])) Those in which a considerable portion of the color remains, viz, Ps. 
slewarli, B. coli, and B. amylovorus. (c) Those in which the color remains the same 
deep red as on the start, viz, Bacillus carotovorus. 

April 18. — About one-twentieth of the color is left in 1 and V; i)recipitate yellow. 
Only aljout one-fortieth of the colcn- remains in 2 and 2'. In 3 there is a})out 5 times 
a.s much color as in 1 and F; in ?/ about twice as much. The color in the latter tube 
is Ridgway's rose pink. The precipitate in 3 and 3^ is yellow; it is most abundant 
in 3^. No. 4 is like 1 and V; ]irecipitatt! white. In 5 and 6 the color is rose pink; 
precii)itate white, more copious in 5 than in 6. In 7-10 a slight wh^'te precipitate 
and no change in color. 

April 2!). — Color gone in 1 and V. On looking through the fluid endwise there is 
a trace of vinaceous buff, but held uyi vertically to the light (Ifi mm. diameter) it 
appears colorless. Nos. 2, 2\ and 4 are like 1 and V, and there is no change in 7-10, 
i. e., it is as red as on the start. The rest of the tubes (3, 3^, 5, and 6) still show 
some color. 

May 16. — Color iias not entirely disapi)eared from 3, '.V, 5, and 6. The color in the 
4 tubes of B. caroiovonis is now only one-half as deep as it was on April 29. The 
vest are still colorless. 

21788— No. 28—01 8 



114 



Litmus. 

For tests made with litmus see under Reduction experiments and 
in various other parts of this paper. 

REDUCTION EXPERIMENTS. 
Methylene Blue. 

The reducing^ tendencies of Ps. hyacinthi and other organisms were 
tested on methylene blue in Dunham's solution (1 per cent peptone and 
0.5 per cent sodium chloride in distilled water). To each 100 c. c. of 
the Dunham's solution, which was made from Witte's peptonum siccum, 
was added 2 c. c. of a solution of 50 mg. of methjdene blue in 50 
c. c. of distilled water. The results obtained are expressed briefly in 
the following table, each organism grew in the medium, but as there 
was no repetition of the experiment some of the statements ma}^ be sub- 
ject to revision: 

Table VII. — Effect of Fs. hyacwthi, etc., on methylene blue in salted j)eptone water. 
Experiment begun March 21. Color of fluid, bright blue. 



Species. 


Reduction. 


Effect of 
shaking. 


Color at close 
of experi- 
ment. 


Precipitate. 


Dura- 
tion of 
experi- 
ment. 


Ps. hyacinthi (2 
tubes). 


Distinct (within a few 
days), and long con- 
tinued. Mar. 27, about 
one-third and one-half as 
blue as checks. Apr. 11, 
one-thirtieth and one- 
fiftieth as much color as 
in chocks. Apr. 18, still 
nearly reduced. Ps. hya- 
cinthi has a marked effect 
onmetliylenebluein this 
solution^ and for a long 
time. Apr. 25, color be- 
gins to return. May 2, 
as much, and nearly as 
much, color as in checks. 


Color returns 
quickly and 
is blue. 


Bright blue. 
Does not 
deepen on 
shaking. 


Notstained 


56 days. 


Ps. campestris 


Distinct (within few days). 
Mar. 30, one-half as blue 
as check. Apr. 11, one- 
fiftieth as blue as check. 


Color deep- 
ens rapidly 
on shaking. 


Green. Does 
not change 
on shaking. 


do 


Do. 


Ps. stewarti 


None. (Observations on 
Mar. 24, 27, 30; Apr. 6, 11. 
18, 25: May 2, 16.) Fee- 
bly but distinctly cloud- 
ed in March, then clear. 


No change ... 


Bright blue. 
Same color 
throughout 
progress of 
experiment 
as on start. 


Deep blue . 


Do. 


B. p y o c y a n e u s 
pericarditidis (1 
tube). 


Distinct (on Mar. 30) . Apr. 
6. Fluid uniformly pale 
greenish instead of bright 
blue; distinctly unHke 
Ps. hyacinthi and Ps. 
campestris; they are 
paler than this tiibe but 
rapidly deepen their col- 
or on sliaking, whereas 
this does not change 
much even on prolonged 
shaking. Apr. 11, about 
one-fifth the color re- 
mains. Apr. 25, one-sixth 
as much color as in check 
tubes. 


Does n o t 
change 
much even 
on long 
shaking. 
Fluid uni- 
formly pale 
greenish. 


Green. Does 
not change 
on shaking. 


Notstained 


Do. 



115 



Tablk VII. — Effect of Ps. hyacinthi, etc., on metJu/lene hhie in salted peptone iruler. 
Experiment begun March 21. Color of fluid, bright blue — Continued. 



Species. 


Reduction. 


Effect of 
shaking. 


Color at close 
of experi- 
ment. 


Precipitate. 


Dura- 
tion of 
experi- 
ment. 


B. coli (1 tube) .... 


Doubtful. Soon heavily 
clouded. Paler blue a"t 
first (in March), then 
doubtful. No reduction. 
Possibly the paler blue on 
start was due to the heavy 
clouding. 


Does not 
change. 
Uniformly 
blue. 


Blue. Does 
not change 
on shaking. 


Dark blue . 


Do. 


B. amylovorus (1 
tube). 


Doubtful. No distinct re- 
duction. Less clouding 
than in B. coli. 


Does not 
change. 


Blue. Does 
not change 
on shaking. 


Deep blue. 


Do. 



From the above table the 6 organisms mentioned appear to fall into 
4 categories: 

(1) Marked reduction, prompt reoxidation on shaking, hnal color 
the same as at the beginning — i. e. , pure blue. Precipitate not stained. 
JPs. hyacivthi. 

(2) As in 1. Ijut the final color of the fluid green. Ps. canipestris. 

(3) Distinct slow destruction of color. Color does not return on 
shaking. Final color green. Precipitate unstained. B. pyocyaneus 
pericarditidis. 

(4) Reduction feeble or doubtful or absent. Final color of the fluid 
blue. Bacterial precipitate stained deep blue. Ps. stewartl, B. coll., 
B. amylovorus. 

Indigo Carmine. 

The reducing tendencies of Ps. hyacinthi and other organisms on 
indigo carmine were tested in the same way as in case of methylene 
blue. The culture medium consisted of 100 c. c. of Dunham's solu- 
tion, to which was added 2 c. c. of a solution of 500 milligrams of 
indigo carmine in 100 c. c. of distilled water. The results obtained 
are shown in the foUowino- table: 



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50th day; 
fewer alive 
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and the pre- 
ceding than 
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on boiling 
acid vapor 
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able smell 
suggestive 
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acid: fluid 
acid after 
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an hour. 


1 
£ 

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Slightly acid. 


No acid reac- 
tion detected 
in either 
tube. Is pep- 
tone neces- 
sary? 


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Reduction be- 
gins. 




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Separation of 
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121 





Slight acidity 
in whey at 
close. 


Slight acidity 
3d and 4th 
weeks. 


casein gray 
white, whey 
pale yellow; 
all reduced 
, except a few 
pale blue 
flecks on yel- 
low rim. 


After 13th day, 
partial before 
22d(inwhey); 
27th, whey 
yellowish; 
43d, w hey 
pale yellow, 
curd grayish 
brown. No lit- 
mus color ex- 
cept in the 
y*> low r i m 
where there 
are man y 
small pale 
blue patches. 


Doubtful, pos- 
sibly some on 

' 7th day: whol- 
ly reduced in 
upper 1 cm. 
on 22d; 27th, 
nearly re- 
duced. 


'i 


After 13th day 
and before 
15th. 


|g 

a) * 
> 


casein blue, 3 cm. deep, not 
solidifled, and settles very 
slowly; 27th, casein blue: 
50th, colorreturniiig; whey 
pale brownish red, casein 
gray below, purjile blue 
above; (I.'itli, lower one-half 
of casein gray, upper one- 
half purple bliie, whey pale 
purplish. 


15th day, 3 to 4 mm. whey on 
top of the uniformly blue 
casein; color deeper than 
check; 22d, curd, uniformly 
blue, not solidified; about 
same color as check; as in 
all of the milk cultures the 
casein has separated out 
slowly as a voluminous, 
noncoherent prei'ipitate; 
27th, curdo em. deep, blue, 
with a traceof purple in it; 
Both, eolor oxidizing back; 
whey dull brownish red, 
upper one-half of casein 
deep hyacinth blue, lower 
one-haif adirtygray: tioth, 
casein hyacinth b 1 u <? , 
whev dull wine red (re- 
flected light). 


15th day, slightly redder by 
reflected light than check 
tube; 22d, litmus in deeper 
parts of tube dull purplish 
blue; 27th, the litmus 
which is not reduced is pale 
purplish red by reflected 
ight: 43d, fluid'and casein 
dull )>urple: 50th, casein 
dull hyacinth blue; whey 
dull wi'ncred (color is bare- 
ly visible by reflected 
light); (i5tli, casein dark 
blue, no purple in it; whey 
dark by reflected light. 


c 

t) o 
a)" 


9th day, no red; 
if any change 
incolor,bluer; 
13th, milk uni- 
formly blue 
and slightly 
deeper than 
the check. 


9th day, no red 
color, l)ut a 
lighter blue 
than check; 
13th, casein 
blue, but pal- 
er than check, 
not solidifled. 




1st, 2d, 8d days, 
n change; 
Gth and 7th, 
color like 
cheek. 


1st, 2d, and 3d 
days, no 
change; 6th, 
no change; 
7th, a trifle 
lighter blue 
than check. 




Good: excel- 
lent yellow 
s u r"f a c e 
growth on 
7th. 


Good; copious 
s u r face 
growth on 
9th day. 




o 


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• 

• 




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122 



cq 



X! 



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n 
< 



Remarks. 


Very slight in- 
dication of 
acidity on 
23d day. 


Slight indica- 
tion of acid- 
ity on 27th, 
43d, and 60th 
days. 


o 


Reduction be- 
gins. 


Doubtful; case- 
in grey blue 
and whey yel- 
lowish on 38th 
day. 


After 13th day. 
Partial in 
whey before 
22d. 


After 15th day. 
Partial on 
31st; nearly 
complete on 
43d. 


Separation of 
casein begins. 


7th or 8th day 
(1 mm. whey 

on 8th). 


After 13th day 
and before 
the 15th, 
whey 4 mm. 
deej) on 15th. 


No separation 
of whey from 
the casein. 


S 
"2 

.a 

o 
o 


17th day, casein blue (R's 
lavender, but twice as deep 
a color); whev not red bv 
reflected ligh't; 23d, fluid 
dull purple by retlected 
light; 3.stli. heated 10 min. 
at6(iO('.; IDlh, casein bluer 
than it was (litmus reoxi- 
dizing), whey dark blue 
by reflected light. 


15th day, casein Alls the 
greater jiart of the culture, 
and is a uniform opaiiue 
lilue, deeper than the 
check; 22d. casein uniformly 
decj) blue, and not coherent 
(solidifleil); it occupies nil 
but uppcrO mm. of llie cul- 
ture: 27tli, whey yi'ilowish 
(reduced); most of culture 
occiqiied by the ^lovvly set- 
lliiig casi'in, wliicli is'blue 
with a purplish tinge; 43d, 
fluid dull inniile liy reflect- 
ed light; nearly ail of the 
casein dissolved; •''lOth, case- 
in dull liyacinth blue; 
whey dull wine red (reflect- 
ed light); (l.'illi, cusein blue; 
whey dark (not red). 


15th day, bluer than check; 
22d, distincdy bluer than 
check; 27th, tiuid uniform- 
Ivblue; growth slower than 
in the other 1 lilies (■l:i0-445) ; 
31st, a decided dulling of 
blue, but no acid reaction; 
.'lOtli, color reluniiiig; fluid 
uniformly deep blue; (i5tli, 
fluiii dee|> blue, wholly 
opa(|ue; distiiicl yellow 
rim and precipitate. 


Color second 
week. 


8th day, same 
as on 5th. 


9th day, no red 
color, doubt- 
ful if any 
change, pos- 
sibly slightly 
bluer; 13th". 
fluid uniform- 
ly blue; slight- 
ly d e e J) e r 
than the 
check. 


9th day, slight- 
ly bluer than 
check; 13 th, 
milk u 11 i - 
formly blue, 
distinctly 
deeper than 
check. 


m 

O 


4th day, bluer; 
6th, deep 
blue— i. e., 
bluer t h a n 
when inocu- 
lated. 


1st, 2d, and 3d 
d a y s , no 
chaiige; 6th 
and 7 th, same 
color as 
check; no 
reddening. 


Ist^ 2d, and 3d 
days, no 
chaiige; 6th, 
like check; 
7th, slightly 
bluer than 
check. 


5 

a 

o 


Prompt; good. 
11 17th 
day, a wide, 
bright yel- 
low rim. 


Good;diatinct 
yellow pel- 
licle on 4th 
day. 


A good sur- 
face growth 
on 7th day; 
22d, bacte- 
rial rim 
bright yel- 
low, but 
n 1 over 
one- ten t h 
as much as 
in 1 h e r 
tubes. 


o 
o 

"i 
o 


Between lav- 
ender and 
royal pur- 
ple. 


o 
•o 


o 


. stock. 

44-1 (430 + 1* 
mill tose); 
i noculated 
anionth lat- 
er from an- 
other cul- 
ture. 


5 


446 (430 -f 24?« 
c. p. glycer- 
ine). 


SI 


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124 

From an inspection of the foregoing table it is evident that, as a 
rule, under the conditions named, Ps. hyacinthi reduced litmus only 
ver}^ slowly. In litmus milk its first visible effect was a deeper bluing 
of the milk, which persisted for some time; the casein was then thrown 
down slowly, and a partial or complete reduction of the litmus usually 
followed. Upon reoxidation, the litmus was again blue. Addition of 
methyl alcohol led to no acid reaction. Addition of ethyl alcohol 
caused the development of a slight quantity of acid, which inhibited 
further growth, but did not immediately destroy the organisms. This 
acid is volatile and the boiling culture smells like acetic acid. Glycerin 
retarded growth, no acid was formed, and the casein did not separate. 
Addition of other substances to the litmus milk — e. g.,mannit, galac- 
tose, cane sugar, grape sugar — led (during the first few weeks) either 
to the formation of no acid or to the production of so slight a quantity 
that it was easil}' obscured by the alkali. 

Ps. campestrls and Ps. jjhmeoU were also tested in litmus milk and 
other litmus cultures. In general, their behavior was like that of Ps. 
JnjactntJii The milk first became deeper blue, the casein was then 
thrown down slowly, and the litmus was reduced. In some cases, at 
least, the litmus was reduced more rapidly by these two organisms than 
by Ps. hijaclvthl. On reoxidation the litmus was blue. 

The relative rapidity of the reduction of litmus is worth noting. 
For instance, in some broths tinctured with this substance and inocu- 
lated with Ps. hyacinthi, all of the litmus color disappeared except in the 
uppermost layers in contact with the air, but this reduction took place 
slowl}^ requiring several weeks, where Bacillus cloacm consumed only 
as many da} s. 

In a litmus cauliflower broth inoculated with Ps. hyacinthi reduc- 
tion was first visible toward the end of the second week and was not 
complete until after the third week. In the same broth inoculated 
with Ps. phastoli reduction })egan to appear at the end of the first 
week and was complete at the end of the second week. In the same 
broth inoculated with an undescribed organism belonging to the B. 
cloacce group ^ there was partial reduction of the litmus in 20 hours 
and complete reduction in 48 hours. 

Ps. stewarti cultivated in the same litmus milk behaved differently. 
It grew well, but the casein was not thrown down and a slight amount 
of acid was formed. This is usually not observable the first week and 
it is often obscured for a long time by the reducing action of the organ- 
ism. The action of this germ on litmus milk is shown in the following 
table: 



^ Isolated from rotting potato tul.iers recei^•e(l from Florida and designated in the 
writer's notes as "The Florida gas-forming wet rot." 



125 





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05 


None to 13th day; 
slight at bottom 
on 15th; on 22d, 
uniform slow re- 
duction. 


On 6th day litmus 
uniformly paler 
than i n c lecks; 
13th, more reduc- 
tion (at top). 


o 
•2.2 

Q 


No separation 
(65 days). 


No separation. 


3 

.a 

o 
§ 


5 

0) 

K 

.Q 

-a 

c 

oi 

.!^ 

0) 

?: 


15th day, no reddening: 22d, color 
now very unlike that of check: 
over one-half the color is dis- 
charged, the tint now being a 
iiniform pale lavender; 27th, col- 
fir pale hi vender except in bot- 
tom, where it is whiter; 32d, color 
lilac; 43ii, lilac; ,50th, color lilac; 
65th, color now lies between lilac 
and heliotrope purple. 


20th day, on the wall above the 
yellow pellicle the litmus is pur- 
ple; mi k pale, but not white or 
gray; it is a color belonging to 
Ridgway's series on Plate VIII; 
it came nearest to a mixture of 
lavender and lilac or lavender 
and heliotrope purple; the pur- 
ple of the rim is deeper, i. e., more 
ike Indian purple. 


O 

§ 

a. 


9th day, deeper 
blue "than the 
checks; 13th, 
deeper blue than 
checks. 


10th day, milk has 
slowly changed 
color; it is now 
heliotrope pur- 
ple; 13th, as on 
10th. 




g 


1st to 6th day, no 
change; 7th, 
slightly bluer 
than check. 


2d day, purple lit- 
mus above cream 
has become blue; 
no other change; 
3d , increased 
bluing of rim: 
6th, fluid paler, 
but still lavender 
blue: 7th, rim 
purple, milk lav- 
ender, but paler 
or redder(?) than 
checks. 


Growth. 


Good; on 13th a 
copious yel- 
1 w precipi- 
tate rim and 
pellicle. 




Color. 






O 

o 




S 






2 





127 



TESTS FOU HYDROGKN SULPHIDP]. 

The tests for HjS were made by suspending in the tops of test tubes, 
containing cultures of Ps. hyacinthi, narrow strips of filter paper 
which had l^een dipped in a saturated water solution of c. p. lead ace- 
tate. The strip was held in place by having its upper end wedged 
between the wall of the tube and the close»fitting cotton plug. The 
following trials Avere made: 

(1) Coconut cullure. — Growth good. Paper introduced on fourteenth day. Result: 
Strip feebly browned in 24 hours. Removed and inserted another moister paper. 
In 48 hours the lower 1 cm. of the strip was distinctly brown, but not deep brown. 

(2) Coconut cullure {from (mother series). — Growth good. Paper introduced on 
fourteenth day. Result: Very marked browning of the lead acetate paper in 48 
hours. After 3 weeks the strip was black in lower one-half inch, and brownish for 
another one-half inch. The bacterial layer was bright yellow and the substratum 
unstained. 

(3) Carrot culture. — Growth good. Paper introduced on the ninth day. Strip 
examined and remoistened on fifth day. Result: No browning of the paper so long 
as the experiment continued (42 days). Substratum browned. 

(4) Potato culture. — Growth good. Paper introduced on fourteenth day. Result: 
No browning of strip so long as under observation (3 weeks). Substratum grayed. 
Fluid feebly browned. 

(5) Rutabaga, culture. — Growth good. Paper introduced on third day. Result: 
No browning of the lead paper in 47 days. A slow browning of substratum, and 
bacterial slime. 

(6) White radish culture.- — Growth good. Pajjer introduced on third day. Result: 
No stain of the strip in 61 days. Substratum browned. 

(7) Yellou) (/lobe turnip culture. — Growth good. Pai:)er introduced on third day. 
Result: Seventh day, copious growth; no stain of the lead pai>er. Eighteenth day, 
a slight browning of the strip at bottom and a fee)>le browning of the upper part of 
the substratum. Twenty-seventh day, a feeble browning of the lower part of the 
lead paper; distinct pale browning of the upper part of the substratum. Thirty- 
fourth day, a slow increase of the brown color in the lead paper; slime neutral. 
Sixty-fourth day, only a slight browning of the lower end of the lead acetate paper; 
substratum brown (burnt umber); fluid grown full (solid) with yellow-brown 
slime; reaction acid. 

Conclusion: I*s. hyaclntld caused prompt browning of lead paper 
when grown on sulphur-bearing sul)strata, which did not stain brown. 
With one exception, there was no evolution of hydrogen sulphide 
(browning of lead paper) when grown on substrata which became gray 
or brown as a result of the growth of the organism, although some of 
these nui.st have been ver}'^ rich in sulphur compounds. Quer}-: Was 
the HgS fixed in the substratum as fast as formed, by anunonia, with 
the resultant brown stain '^ See The Brown Pigment. 

Pa. campestris behaved in much the same way. The lead paper was 
promptly browned when exposed over cultures on coconut, and the 
substratum was not stained. Exposed over potato and rutabaga, 
there Avas no browning of the paper, but a brown .staining of the sub- 
stratum. Exposed over white radish and 3^ellow globe tiiiiii]), oj 



128 

which growth was prompt and very copious, the paper browned slowly 
and the substratum also finally changed to brown. In a tube of radish 
there was no visible browning of the paper up to the fourteenth day 
of exposure, and on the same date there was only the merest trace of 
browning on the lower margin of the strip in the* tube of yellow globe 
turnip. On this date there was an equally good growth in the 2 tubes, 
but there was no stain of the substratum in the tube of radish, while 
there was a distinct browning of the whole substratum in the tube of 

turnip. 

Ps. stewarti grayed potato cylinders, but did not brown the lead 
paper (9 days' exposure). On rutabaga and yellow globe turnip it 
neither browned the paper nor stained the substratum (64 days). Also, 
on white radish in 6-i days the substratum was not stained, but no test 
was made for H2S. 

Bacillus coll and an undetermined white organism (received as B. 
coll from the bacteriological laboratory of the Army Medical Museum), 
grayed potato cylinders promptly, but there was no browning of the 
lead acetate paper in 58 days. 

For behavior of Ps. pJiaseoli see The Brown Pigment. 

FORMATION OF INDOL. 

The pink or red indol reaction was obtained with Ps. hyacinthi by 
adding sulphuric acid and sodium nitrite to cultures in Dunham's solu- 
tion, in peptonized sugar-free beef broth, and in peptonized Uschinsky's 
solution. My practice was to add to the culture 15 drops of a mixture 
of sulphuric acid and water (2 acid, 1 water), and then 1 c. c. of distilled 
water containing 0. 1 per cent sodium nitrite. If the color did not come 
at once, or within a few minutes (which was frequently the case), the 
tubes were plunged into water at 75° to 80° C. for 5 minutes, during 
which the color appeared. The color was a distinct red or pink. Unin- 
oculated tubes tested at the same time gave no such reaction. Cultures 
of various ages were used, but none less than 3 weeks old. Old cul- 
tures must be used to obtain a distinct reaction, and in none was the 
color more than one-quarter as deep as that in corresponding tubes of 
Bacillus coli. In no case could any indol reaction be obtained from 
culture fluids which did not contain peptone. The same result was 
obtained with B. coli and a half dozen other organisms us.ed for com- 
parison. The presence in the culture fluid of peptone (using this term 
in the commercial sense) appears to be necessary for the production of 

indol. 

The indol reaction was also obtained from cultures of Ps. campestris^ 
Ps. stewarti, and Bacillus amylovorus. 



129 

TESTS FOR NITRITES. 
Peptonized Beek Broths. 

Two stocks were used: (1) A strongly alkaline beef broth (stock 
382) with addition of 1 per cent Witte's peptonum siccuni; (2) a 
slightly alkaline beef broth deprived of its muscle sugar by growing 
B. coll in it for 17 hours in the thermostat. This latter was clarified 
with the whites of 4 eggs, which were neutralized by HCl, and for- 
tified with 2 per cent Witte's peptone. These cultures were tested on 
the twenty-second day after good growth. Neither gave any nitrite 
reaction with the indol-sulphuric acid test, the indol being that nor- 
mally present in the cultures. 

Peptonized Uschinsky's Solution. 

This stock consisted of Uschinsky's solution with the addition of 1 
per cent Witte's peptone. The tests were made at the end of 22 days. 
There was no nitrite reaction with the indol-sulphuric acid test, the 
indol being that normally present in the cultures. 

NiTKATE Bouillon (Stock 474). 

This consisted of — 

Distilled water, 1,000.0. 

Witte's peptone, 10.0. 

Beef extract, 2.5. 

Chemically pure potassium nitrate, 3.0. 

and sodium hydrate sufficient to render the fluid -flO of Fuller's scale. 

P8. hyacinthl grew readily in this medium without gas production. 
Examinations for nitrite were made on the sixth, sixteenth, and 
twentieth days, using the iodine-starch test — i. e., to each tube was 
added 1 c. c. of thin boiled starch water, 1 c. c. of one-half per cent 
potassium-iodide water (which should be freshly prepared), and finally 
a few drops of a fluid con.si.sting of 2 parts of c. p. sulphuric acid and 
1 part of distilled water. No trace of nitrite reaction could be 
obtained with this reagent. Subsequently grape sugar was added to 
some tubes of this nitrate bouillon (100 milligrams per 10 c. c), but 
even in the presence of this agent Ps. hyacinthi was unable to reduce 
any nitrate to nitrite (8 days). 'I\il)es of Baclllm coli and of Bacillus 
carotovorus were used for comparison. These became blue-black, like 
ink, on addition of the sulphuric acid. 

1^8. cdvipeHtrls and l*>i. xtnoartl resemble Px. hyachiflii. Neither one 
is able to reduce potassium nitrate to nitrite in peptonized ))ouillon 
cultures, either with or without grape sugar. Comparisons were also 
made with Bacillus am.ylovonix and B. j^liocyaneus j^ericarditidis. The 
former does not reduce nitrates to nitrites. The latter (like various 
21788— No. 28-01 1) 



130 

other green-fluorescent bacteria) first converts the nitrate to nitrite, 
and then liberates the azote as free nitrogen.' Gas bubbles were given 
ofl' continuall}' during the first few days, so that the top of the fluid 
was foamy, as if it had been shaken violently. During this stage the 
liquid gave a deep blue-black reaction with boiled starch water, potas- 
sium iodide, and sulphuric acid. Later the gas bubbles disappeared, 
and then (sixteenth day) no nitrite reaction could be obtained. The exper- 
iment with B. pyo. pericardii Idis was repeated, using fermentation 
tubes; a considerable quantity of gas collected in the closed end. This 
gas was not absorbed on shaking with caustic soda (absence of CO.^); 
it did not diffuse quickly or explode when it was tilted into the open 
end of the tube and a lighted match applied (absence of I13 drogen and 
marsh gas): lighted matches thrust into the ])owl were repeatedly 
extinguished (presence of nitrogen). 

One or two other interesting facts were observed in connection with 
cultures in the nitrate bouillon. /*y. stewarti and B. mnylovorus made 
a very feeble growth in comparison with Pi<. hyacintJd and P><. cmiLpes- 
tris. B. coli grew l)etter, throwing down in 16 days about 10 times 
as much precipitate as B. <iinylov<yru8. In early stages of growth, i. e., 
during the first 2 or 8 days, the -1 cultures of I\. campestrls were ver}^ 
different from those of /*s-. hyachitJu in that the former contained 
many hundreds of tiny white zoogkjea^ scattered uniformly through the 
liquid, giving it. especially under the Zeiss X 6 aplanat, a distinctly 
granular appearance. On the sixteenth day this phenomena had dis- 
appeared and the cultures of the two organisms were then much alike. 

Ps. p>haseoli was also tested in this nitrate bouillon. Like Ps. cam- 
pestris, it formed great numbers of small zoogloese during the first few 
days of growth. It was entirel\' unable to reduce the nitrate to nitrite 
in this solution (14 days). 

FERMENTS. 

No attempt has been made to isolate any ferment, but the behavior 
of Ps. hyacinth I in the host plant and in various culture media leads 
to the conclusion that several enzymes are secreted. 

Cytase. 

The thin, non-lignified walls of the spii-al vessels of the host plant 
are dissolved, letting the bacteria out of the vascular system into con- 
tact with the parenchyma. Fragments of the spiral threads are 
apparently all that remain of these vessels in bundles which have been 
long occupied. Once in contact with the parenchyma, cavities, filled 
by the l)acteria, are formed in this tissue, the cells being first sepa- 
rated from each other and finally destroyed, as Dr. Wakker has 
described. These facts indicate the secretion of a cytohydrolytic 
enzyme. At the same time the slowness with which the vessels are 



* These are the organisms that reduce the value of the farmer's manure pile. 



lai 

destroyed and the cavities formed lead me to think that this substance 
is secreted only in extremely small quantities. The results of srrowth 
on different yegetable culture media point to the same conclusion. 
No softening of the cell walls was observed in any of the following 
substrata: Potato, sweet potato, sugar beet, coconut. A softening 
of the middle lamella of carrot, turnip, and radish cylinders, was noted 
in old cultures.^ 

A few observations were made on the related organisms. Potato, 
coconut, rutabaga, yellow globe turnip, and radish cjdinders were 
not softened by P)i. steiaartL Ps. cairvpedrin softened cylinders of 
potato, rutabaga, and yellow globe turnip. 

The behavior of !*><. cam,pei<trh in the interior of various host plants, 
in the absence of any other organism, indicates that a cytase must be 
present, i. e. , closed cavities are formed. During the formation of these 
cavities, which are fully occupied b}^ the bacteria, the parenchyma cells 
are first separated from each other by a multiplication of the organism 
in the intercellular spaces, the walls of the cells are then crushed 
together b}' the continued multiplication of the bacteria, and become 
more and more indistinct, until they finally disappear altogether. 

In properly fixed, paraffin-embedded material, cut in serial section, 
all stages of the solution of the cells and the formation of these bac- 
terial cavities may be readily observed,. especially in the easily sec- 
tioned cabbage and turnip occupied b}^ Px. cainjjedri.s. The organisms 
find their way into the parenchyma from the vessels, which are first 
occupied in ways alread}^ described by the writer elsewhere. That the 
destruction of the cell walls can be due to nothing but this organism, 
in the disease under consideration, is shown clearly as follows: (1) 
Because these are closed cavities, i. e., not in open connection with 
the surface of the plant, except at long distances from the place of 
occurrence; (2) because these cavities occur as freely in the interior 
of plants that have become diseased from the writer's pure-culture 
inoculations as they do in those which have become diseased naturally 
in the fields; (3) because the microscope shows the cavities to be filled 
exclusively by bacteria; (4) because cultures made from the interior 
of such inoculated and diseased plants have shown 1\. canipestris to 
be the oidy organism present; (5) because all stages in the destruction 
of the cells and in the formation of these cavities can l)e followed in 
serial sections, so fixed and otherwise prepared that the relation of the 
bacteria to the various parts of the host plant is the same as iji the 
living plant. 

/'!s. pha.'^eijli also forms cavities in the interior of the host plants. 
Concerning Ph. uteiom'tl 1 am in doubt. 

' Sinc(> this was written, and ti)o lato to doterinine ex)>erinit'ntally, it lias occnncil 
to inc, as till- result of readini,' I'ottcr's paiu-rs, tiiat pussil)!}' tliis solvent artinn on 
the middle lamella is dne to the formation of anil ammonium oxalate. It cannot be 
(hie to oxalic acid as such since this has no solvent action on turnip tissues. 



132 



Invertase. 



A slant tube of 10 per cent cane .sugar agar, fragments of which gave 
no precipitate of copper oxide on boiling 2 minutes in Soxhlet's solu- 
tion, gave after Ps. hyadnthi had been grown on it for 29 days, a very 
copious rust}" precipitate after boiling 2 minutes in the same solution. 
Cane-sugar bouillon gave the same result. This indicates that cane 
sugar is inverted, and to a much greater extent than is needed for the 
growth of the organism, but we may not therefore assume the existence 
of an invertase. The fact that cane sugar was not inverted when put 
into dead or sterile tubes of 7^s-. liyacinthi cultivated in beef broth and 
peptonized beef broth, seems to show either that the living organism 
itself is necessary to bring al^out the inv^ersion or else that invertase is 
formed only when it is required, i. e., in the presence of cane sugar. 

My first experiments were in non-peptonized alkaline beef broth 
(stock 382). The contents of tubes 3, 1, 7, 10, 12, and 15 of February 
7 (cover-glass inoculations 21 da}^s old) were poured together and forced 
through a Chamberland filter. Two 10 c. c. portions of the sterile fluid 
were then pipetted into cotton-plugged sterile test tubes, and to each 
was added 3(>0 milligrams of cane sugar. To one of these tubes chloro- 
form was added and to the other thymol. The}' were then set away at 
18° to 24° C. 

On the fifth da}" each tube was tested by pipetting 2 c.c. of the clear 
fluid into boiling Soxhlet's solution, and continuing the boiling H 
minutes. In neither case was there any reduction. These tests were 
repeated on the thirty-fifth day with the same negative result. 

A duplicate series from tubes 1, 8, 11, and 18 of February 7 (same 
stock) led to the same result. In neither portion was there any reduc- 
ing sugar on the fifth or thirtv-fifth dav. 

Thinking that the invertase might possibly have been retained in the 
walls of the filter, or that the presence of peptone might be essential to 
the formation of invertase, the experiment was repeated as follows: 

Three old cultures of Ps. hijdcinihl — (1) in beef broth with Wittes's peptone (459); 
(2) in beef broth without peptone (382), and (3) in beef broth with the trace of 
muscle sugar removed by B. coli (404) — were sterilized by heating them for 10 min- 
utes at 54° C, viz, at a temperature high enough to kill the organism and low enough 
to be harmless to invertase. To each tube was then added 500 milligrams of cane 
sugar and 150 milligrams of thymol. The sugar was transferred from a sterile solu- 
tion by means of a sterile pipette. Along with these three cultures two other old 
cultures were tested, viz, one of P.s. rumpestris and one of Ps. stewarti, each in stock 
382. These tubes were set away for 19 days at 25° to 30° C. 

At the end of this period they were tested as follows for the presence of reducing 
sugars: 

Twenty-five cubic centimeters of Soxhlet's standard alkaline solution was added to 
25 c. c. of his standard copper sulphate solution, and after mixing was divided into 
5 equal parts in 5 clean porcelain capsules and 40 c, c. of distilled water added to 



133 

each one. The fluid in one of these capsules was then brought to a boil and 1 c. c. 
from one of the tuhen was added to it and the boiling continued for 1 h minutes. In the 
same way each of the other tubes was tested. In none oi the 5 capsules was there 
any reduction of the copper. 

A more conclusive test would })e to grow these organisms in sugar 
bouillon for some weeks and then determine per cubic centimeter the 
exact copper-reducing power of the cultures. These should then be 
heated 10 minutes at 54^^ C. , or thereabouts — i. e. , long enough to destroy 
the organisms. Thereupon, measured volumes should be pipetted into 
sterile cane-sugar solutions. To similar solutions should be added equal 
portions from the cultures after heating them for 10 minutes at 80° or 
90"^ C. — i. e., long enough to destro}' the supposed invertase. Then 
after some weeks, if the fluids have remained sterile, their reducing 
powers should be determined quantitatively. An experiment of this 
sort was begun with i^y. hyachdld^ but was lost through a contamina- 
tion which was probably introduced with the thymol. At least the 
intruding white organisms were capable of growing in the presence of 
an abundance of this antiseptic at a constant temperature of 50° to 
52° C. 

As the writer has had no opportunity to repeat the experiment, the 
question of an invertase must be left an open one. This only is toler- 
ably certain — none is formed in the absence of cane sugar. 

All of these 4 yellow organisms invert cane sugar readily, as already 
pointed out. 

Diastase (Amylase). 

The experiments with starchy media, already described, show that 
the diastasic action of Ph. hyacinthl is very feeble. Nevertheless, 
some growth occurred, even when the greatest care was taken to 
exclude all carbohydrate food except pure starch; and as tests with 
iodine water and with Soxhlet's solution showed that there had been 
a slight action on the starch, minute quantities of a diastatic ferment 
must be secreted. The starch which has been acted upon gives the 
red or amylodextrine reaction with iodine. Ps. stewarti acts on starch 
slowly, after the manner of Ps. hyacinthi. 

On the contrary, Ps. enmpestris and Ps. j)h(Lseoli destroy starch 
and amylodextrine promptly in considerable quantities, so that in 
course of a few weeks none, or very little, is left in the culture tube, 
even when there were several grams of starch at the outset. 

Experiments with both Pa. campestris and Ps. 2)haseoli showed that 
starch was converted in the absence of the bacteria (tubes heated for 
some miiuites at a few degrees above the thei-mal death point and some 
of the fluid then added to potato starch with antiseptic precautions) 
and that none was converted if before adding them to the starch the 
fluids were heated to a point above that at which diastase is destroyed. 



134 



Trypsin. 



A peptonizing- ferment must be present, since gelatin and Loeffler's 
solidified blood serum are liquefied, and casein is slowh^ dissolved 
with the formation of tyrosin. This, also, is secreted in minute 
quantities or else is partiall}" inhibited b}" other substances, because 
gelatin is liquefied very slowly even under favorable conditions — i. e., 
optimum temperature, proper alkalinity, and suitable food. 

Ps. campestru and Ps. phaseoU behave in the same way — i. e., they 
liquefy gelatin and Lfjeffler's solidified blood serum and dissolve 
(peptonize) casein. These processes take place more rapidly than in 
case of Ps. hyacinth)'., but in none of them is the peptonization speedy. 
Ps. stewarti does not liquefy gelatin or Loeffler's solidified blood 
serum. 

Lab Ferment. 

The existence of a lab-or rennet ferment is at once suggested b}^ the 
fact that in milk cultures the casein is thrown out of solution in the 
absence of any visible production of acids (see Milk and litmus milk 
and Litmus under reduction experiments). The casein is also pre- 
cipitated if the whey from old alkaline milk cultures is first sterilized 
by heating it for ten minutes at 56^ C. and then added to tubes of 
sterilized milk along with thymol. Media inoculated from the thus 
coagulated milk remained sterile. 

The same whey, after heating for ten minutes at 90° C, had no 
effect upon milk. 

Ps. campestris and Ps. j>hmeoU behave in the same way. Both 
throw down casein by means of a lab ferment. Ps. stewarti., on the 
contrary, produces no lab ferment and never coagulates milk. 

Oxidizing Enzymes. 

No oxidase or peroxidase was detected — i. e., the cultures of Ps. hya- 
cinthi did not react blue with sensitive guaiac resin in alcohol nor was 
there any bluing on the subsequent addition of hydrogen peroxide. 
Ps. campestris behaved in the same way. The brown stain is believed 
to be due to other causes. 

A copious evolution of gas T)ubbles took place when hydrogen perox- 
ide was added to old potato cultures of Ps. hyacintld.^ Ps. campestris^ 
Ps. phaseoli and Ps. stevmrti. 

Such copious evolution of oxygen is, however, not peculiar to these 
particular parasites. It has been more recentl}" observed by the writer 
in case of old potato cultures of Bacillus colj, B. amylovonis., B. jjyo- 
cyaneus j^ericarditidis, a fluorescent germ obtained from fermenting 
tobacco and able to grow in the presence of thymol, Earle's bacillus of 
tomato fruit rot, an orange colored clump}" organism from cotton 



135 




leaves, a dendritic yeast, and a nondendritic yeast (both yeasts were 
obtained from the sticky surface of Niagara grapes). In all of these 
cases the gas soon foamed over the top of the test tube. An old 
coconut culture of Px. hyacinth! also gave a very considerable quan- 
tity of gas. 

The least amount of gas was obtained from adding HgO^ to 3-months- 
old potato cultures of Jones' carrot rot bacillus. Three tubes were 
tried, all of which behaved alike. At first there was no gas, then a 
slow, long continued evolution of small bubbles, the total not l)eing 
very great. A young potato culture of this bacillus (8 days old) 
yielded gas almost from the start and in much greater quantity than 
the old cultures. The reverse was true of Ps. campestris. A potato 
culture ?> months old yielded gas more 
promptly and in greater volume than did 
a vigorous culture made from the same 
tube and only S days old. Both, how- 
ever, yielded nuich gas. On the con- 
trary, even that from the young cultures 
of Jones's bacillus fell far behind in 
amount that which was evolved by the 
other 10 bacteria and by the two yeasts. 
Some gas was also obtained by pouring 
H3O2 upon old rice cultures of various 
funo'i, e. 2"., Fusarmm niveuri). F. vasin- 
feet aril, Swingle's Atta fungus (culti- 
vated by the writer from a nest of Atta, 

near Washington), and from an agar plate 

culture of cotton anthracnose. 

The yield of gas from the fungi named 

was insigniticant in comparison with that 

obtained from the yeasts and from the 

bacteria, exclusive of the old cultures of 

Jones's bacillus. The other bacilli and 

the two 3^easts gave so much gas that 

the tubes were tilled and frothed over, 

usually within a few minutes. 

In the accompanying illustration (fig. 2) a 3-months-old potato culture 

of Ph. pkmeoli to which H.,0., has been added is shown by the side of a 

check tube (uninoculated) to which H^Oj has also been added. In the 

one case there was a very copious evolution of gas bubbles, which 

tilled the tube; in the other there was only a very slight evolution of 

gas, which soon ceased. 

On heating a 3-months-old culture of Ph. phmeoU for 25 minutes at 

75 ' to 85^ C, and then adding the H,0.„ there was no evolution of gas 




Fig. 1. (a) Evolution of gas on add- 
ing hydrogen peroxide to potato 
culture of Ps. phamdi: (b) Unin- 
oculate<l lulie, to which hydrogen 
peroxide has just been added. 



136 

at first, Imt after a few minutes ]ml)l)les began to be given off and a 
small amount of froth collected, but not over one tive-hundredth as 
much as from the unheated tube. This tube was, of course, full of a 
thick 3^ellow slime, which perhaps conducted heat badly. 

In a second test, a similar potato culturt^ of ii-. phaseoli was exposed 
for 2 hours at 85^ C. On then adding H.O^ there was no evolution 
of gas either immediately or after a time. A similar potato culture 
of Ps. cmnpedTtH^ treated in the same way, behaved the same— there 
was no evolution of gas. The above illustration would serve equally 
w^ell for the behavior of tubes of Pa. eaiiq)c^trii< or Ph. 2jhaiieoU before 
and after heating to H-o"^ C. 

As already shown, both Ps. phaseoJ! and I's. ca/npeMrisyfhen grown 
on potato produce an abundance of diastase, but the breaking up of the 
HgO. with liberation of oxygen can hardly be due to that enzyme, for a 
potato culture of i^-. hyacinth! of the same age as the preceding gave 
an enormous quantity of gas, although, as usual, it had made a rather 
meager growth (owing to its feeble diastasic action). This potato gave 
a strong starch reaction with iodine potassium iodide. Stearns & Co.'s 
pancreatic diastase also failed to cause any evolution of gas when it was 
dissolved in water and HgO,^ added. 

Dr. Oscar Loew has given reasons for believing that this decompo- 
sition of hydrogen peroxide is due to a hitherto unsuspected oxidizing 
enzyme, which he has named catalase.^ and which he believes to be 
universally distributed in plants and animals and to have to do with 
respiration. 

PIGMENT STUDIES. 

The Yellow Color. 

Dr. Wakker appears to have been uncertain whether the yellow color 
was inherent in the organism itself or only in a gmmny substance 
surrounding it. 

The yellow color of Ps. lujacintlil can not be shaken loose or filtered 
away from the ])acterial cells by water, and, with the exception of 
nutrient starch jelly containing glycerine, it was never imparted to 
any of my fluid or solid culture media, whether neutral, acid, or alka- 
line. It pertains oidy to the bacteria themselves. Working in a 
good light with the best appliances at my disposal, viz, Zeiss 2 mm. 
apochromatic, 1.40 n. ap., with 12 and 18 compensating, oculars, it has 
never been possible to locate the yellow pigment in any gum or gran- 
ules lying betw^een the cells. In my opinion the color is lodged within 

1(1) Physiological Studies of Connecticut Leaf Tobacco. Deiiartinent of Agricul- 
ture, Washington, D. C, 1900; (2) Catalase, a new en2ynie of general occurrence, 
■with special reference to the tobacco plant. Report No. 68, United States Depart- 
ment of Agriculture, Washington, Government Printing Office, 1901, i)p. 47. 



137 

the organism^ and is insoluble in water because it is dissolved in an oil 
secreted by the cells. The small size of the rods and the minute 
quantity of pig-ment in each one, has made it impossible to decide 
whether the color is lodg-ed in the cell wall or in the cytoplasm itself. 
In whichever place, it appears to be uniformly distributed. 

The intensity of the color depends, of course, on the density of the 
growth and also to some extent on its age and on the nature of the 
culture medium. It is alwa3's a distinct yellow. In the host plant it 
is chrome 3'ellow to pale cadmium. It is also bright yellow on many 
culture media, especially when grown in the dark, e. g. , gamboge, 
chrome yellow, or canarj^ yellow. Occasionally, in cultures, it has 
been as pale yellow as primrose or maize yellow, but this has been the 
exception, and in some of these very pale cultures many involution 
forms were present. On some media, but not on all, old cultures be- 
came brownish or dirty yellow. In such cultures the slime has been 
dull yellow, dirty yellow, dark yellow, brownish yellow, ochraceous, 
and between ocher yellow and tawny olive. In young cultures, and 
in old cultures in which the brown stain was not detected the following 
shades of j^ellow have been seen: Primrose, maize, Naples j^ellow, wax 
yellow, gallstone j^ellow, saffron yellow, buff yellowy Indian yellow, 
gamboge, chrome 3'ellow, deep chrome, lemon yellow, and canary yel- 
low. The color was very dull in potato Ijroths, but the whitish rim 
from such tubes made a homogeneous bright yellow growth when 
rubbed on suitable culture media. The color was also dull 3'ellow in 
acid (unneutralized) beef broths, but in alkaline (soda) ones of the same 
origin it was bright (c*anary) yellow. The color was bright yellow in 
strongly alkaline gelatin and also in cane-sugar gelatin which had been 
acidified with malic acid. Excess of malic acid in the gelatin appeared to 
favor the development of the color, it being decidedl3^ brighter in +54 
than in +80 gelatin. The color did not appear to be an3^ brighter when 
the organism was grown in the ice chest at 8'-' to 12^ C. than when 
grown (in an equall3' dark place) at room temperatures of 25^ to 30'^ C. 

This color appears to be an oxidation product. It forms abundantly 
only in organisms near the surface of solid and fluid cultures. It is 
bleached by reducing agents, and regains its color after these have 
been removed. It does not form so abundanth' when the organism is 
grown on suitable media in air containing a considerable reduction of 
free ox3'gen, i. e., on potato or coconut in nitrogen or carbon dioxide 
mixed with air. In these gases, when pure, there is no growth. In 
partial vacuum growth is less abundant and the color is paler yellow 
than in air. The same is true in nitrogen containing some ox3'gen, 
i. e., in air with the oxv'gen incompletel3' removed. (See Aerobism.) 

The following substances bleach this color: Sulphuric ether, chloro- 
form, turpentine, benzine, benzole, xylol, toluol, carbon bisulphide 



138 

(contaminated with HgS)/ and nascent hydrogen. The loss of color 
was most rapid in the carbon bisulphide, 30 to 60 minutes sufficing, in 
some cases, to render the bright yellow bacterial slime as white as 
white lead. On removing this fluid, which was neutral to litmus, but 
the vapor from which browned lead acetate paper, the A^ellow color 
began to I'eturn in a few hours and linally became nearly as ]>right as 
before. The other substances reduced the color more slowly, and on 
their removal it was a nuich longer time in coiuing V)ack. and never 
became quite as bright as at first. The test with hydrogen was made 
as follows: The pigment was extracted b^^ 23 days' exposure to c. p. 
gl37cerin. Into this 3'ellow glycerin was then thrown a small scrap 
of zinc and some 30 per cent c. p. HCl., which caused a continual evo- 
lution of oas. On the sixth day the yellow color was still visible: on 
the seventh day it was nearly gone; on the tenth daj' it was all gone. 
On the thirteenth day the zinc was removed from the now colorless 
fluid. The fluid remained colorless for some days (a week or two). 
It then very gradually changed to 3^ellow; 54 days after the removal 
of the zinc it was still only feebl}^ yellow. The 3^ellow color was not 
dissolved out b}^ an}^ of these reducing su])stances; at least no ^^ellow 
stain was imparted to the fluids. The bacteria were hardened by alco- 
hol, ether, and chloroform into tough masses not easily divided. Simi- 
lar masses remained soft under xylol, toluol, and turpentine, and had 
an unctuous feeling when touched with a glass rod. Owing to the 
hardening action of chloroform, the writer uses it in preference to 
turpentine or xjdol in passing the tissues from absolute alcohol into 
parattin. In sections cut therefrom the tissues of the host plant will 
tear or become displaced more readily than the bacterial sheet. 

This pigment is slowly soluble in glycerol, as Wakker pointed out. 
It is also soluble in water containing hydrogen peroxide, in ethyl and 
methyl alcohol, in acetic ether, and in acetone. The latter proved the 
most ready and satisfactory solvent, most of the color being removed 
in 30 to 60 minutes. Eth}^ and methyl alcohol and ethyl acetate are 
rather slow and feeble solvents. The color is slowly soluble, without 
destruction, in strong ammonia water; it is quite soluble in water 
saturated with ammonium carbonate. It is also soluble on long stand- 
ing in glacial acetic acid. It is insoluble in petroleum ether. It was 

. N 
not dissolved or changed b}" remaining 30 da3's in — HCl. The color 

was not destro^'ed b}' steaming 25 minutes in water, nor by boiling in 
strong ammonia water. It was not reduced by steaming in water con- 
taining grape sugar. 

The acetone extract appears to ])e sensitive to light. On exposing 

' This is the carbon bisulphide which was used in my experiments with Ps. cam- 
pestris (Centralb. f. Bakt., 2 Abt., Bd. Ill, page 479). 



139 

•JrO c. c. of the yellow acetone extract for some hours tobrisfht sunshine 
on a tin roof, at 50° to 60° C, the fluid was reduced to 1 c. c, but 
instead of being an intense yellow, as was expected, it became a very 
pale yellow — i. e., there was less yellow in the 1 c. c. remaining than 
in the same quantity of the original fluid. 

This color is not an oil, but seems to be intimately associated with 
such a body. On evaporating a yellow acetone extract (organism 
grown on sugar beet) to one-tenth or one-twentieth of its volume, the 
perfectly clear fluid became whitish cloudy, like an emulsion, and on 
examining it under the microscope it was seen to be composed of 
innumerable round bodies having the optical and chemical properties 
(osmic acid test) of oil globules. The yellow color was visible where 
these globules were massed, and also in noncrystalline patches, but 
separate oil globules did not appear to be yellow. 

On driving ofl' the remainder of the acetone with gentle heat, a 
small amount of chrome yellow, oily looking and oily feeling fluid 
remained in drops on the bottom of the white capsule. On adding 
concentrated c. p. HgSO^ to these yellow wet-shining drops there was 
an immediate decided blue-green reaction, which quickly changed to 
brown and soon after to brown-purple. After one-half hour an oily 
looking rim of brown-purple granules surrounded the drops of acid. 
This purple color was also fugitive, fading to a dirty gray. The 
acetone which was used changed to a clear brown on adding c. p. 
HgSO^, but with no preliminary blue-green color. The yellow resi- 
due which remained on evaporating the acetone extract from another 
lot of cultures (organism grown on coconut) changed at once, on add- 
ing concentrated c. p. HgSO^, into a green, which soon faded to purple. 
On adding the acid directly to the bacterial slime dried on glass slides 
it became orange-brown, then rusty-brown, and finall}^ rose-brown, 
but no green or blue color appeared. 

The presence of highly organized nitrogenous bodies is not necessary 
to the formation of this color. It is produced readily in Uschinsky's 
solution, with starch substituted for glycerin, and on this medium the 
yellow color is as pure and as bright as it is in the host plant or on 
coconut, sugar beet, peptone agar, or sugar gelatin. 

These results lead me to think that this yellow color belongs to the 
Lipochrome group of plant pigments. (See Zopf : Die Pilze, p. 144.) 

So far as I have tested it, the yellow pigment of Ps. campestrt's 
l)ehaves in the same wa}^, i. e., it is soluble in glycerin, eXhyX alcohol, 
methyl alcohol, acetone, ammonium carbonate in water, and glacial 
acetic acid-, it is insoluble in sulphuric ether, chloroform, xylol, toluol, 
or carbon bisulphide, but is bleached ))v these substances. As a rule, 
the yellow color of /^v. hyacinthi is brighter than that of l^a. campestru 
or P^. phaaeoii. 



14P 



The Bkown 1'i(;mknt. 



Under certain circumstances, not clearly understood, a pale brown 
pigment, soluble in water, is also produced b}^ Ps. hyaclnthi. 

This feeble brow^n stain occurs in the host plant; in hyacinth broth; 
in alkaline peptonized beef broth (after 5 or 6 weeks); in one-half 
strength potato broth with 1 per cent Witte's peptoiuim siccum (not 
when the peptone is omitted); in the same peptone potato broth with 
addition of malic acid; on radishes (49 days, not in 25 days), white 
turnips, and yellow turnips; on banana pulp and banana rinds; and in 
water surrounding potato cylinders, the potato itself being grayed. 

This pigment did not appear in any of the following media, not 
even in very old cultures: Acid beef broths (55, 59, 75, 80 days); alka- 
line beef broths free from peptone (83, 67, 71, 97, 100, 119 days); alka- 
line beef broth Avith cane sugar (26, 39, 67, 82, 98 days); distilled 
water with 4 per cent maltose, 4 per cent dextrine, and 4 per cent 
Witte's peptone (29, 40 days. Doubtful at the end of 70 days— no 
brown stain in one tube and a slight (?) browning in the other); 4 per 
cent peptone water (15 days); one-half strength potato broth (73 days); 
the same with small amounts of caustic soda (59,73 days); Uschinsky's 
solution (S3 days); standard agar containing some muscle sugar, acid- 
ity +22 of Fuller's scale (22 days); standard agar containing no 
muscle sugar, acidity +15.5 (13, 18, 47 days); the preceding agar with 
grape sugar (18, 29, 47 days); the same with cane sugar (29, 47 days); 
the same with fructose (31 days); litmus alkaline gelatin (39 days); 
malic acid gelatin (34 days); malic acid gelatin with cane sugar (174 
days); gelatin neutral to phenolphthalein with soda (87 days); the same 
with cane sugar (61 days); sugar beet (55, 60, 67, 70 days); coconut (49 
days, 95 days); potato with cane sugar (2 tubes, 67 days— a third tube 
showed slight browning on sixty-seventh day, but less than tubes 
without the sugar); nutrient starch jelly made from Uschinsky's solu- 
tion by substituting washed potato starch for the glycerol (35, 62 
days); the same with Taka diastase (39, 62 days); the same with malt- 
ose (30 days); the same with dextrine (30 days). 

In the inoculated hyacinth plants the brown stain was not very 
noticeable, being confined, so far as observed, to the vascular bundles 
of the diseased leaves, and easily overlooked. In nutrient media the 
pigment does not appear immediately and is best observed in old cul- 
tures (1 to 3 months). It is never as pronounced, either in the host 
plant or on culture media, as the similar pigment formed by Ps. cani- 
j^estria. The most decided browning was in old cultures on crucifer- 
ous substrata and on banana skins. My failure to obtain any brown- 
ing in gelatin cultures contradicts Dr. Wakker's statements, but this 
contradiction maybe apparent rather than real — i. e., dependent, pos- 
sibly, on differences in the chemical composition of the nutrient gela- 



141 

tins employed. On the other hand, it is pro])able that the browning 
he observed arose from the presence of some intruding- organism — 
e. g., the one which produced gas bubbles in his gelatin. 

The following shades of brown were observed: (1) A slight browning 
(yellow banana pulp, 55 days; water around potato cylinders, 31 days); 

(2) feeble brown (white turnip, 22 days; water around potato cylin- 
ders, 24, 37, 67 days; washed potato starch cooked in distilled water 
with 1 per cent Witte's peptone, 73 days; hyacinth broth, 59 days); 

(3) pale brown (yellow turnips, 23 days; one-half strength potato 
broth with 1 per cent Witte's peptone, 41, 59, 73 days; the same with 
malic acid, ^1, 73 days); (4) brownish (a potato cylinder with 500 mgs. 
Merck's diastase of malt absolute, 41 da3^s); (5) feeble reddish brown 
and later brownish white with the slightest trace of pink (washed 
potato starch with 4 per cent peptone water and Taka diastase, 44, 73 
days; also the same stain without the diastase ])ut feebler); (6) tawny 
olive (white turnips, 40 days); (7) paler than tawny olive (yellow tur- 
nips, 22 days); (8) ochraceous (white radish, 50 days); (9) russet (white 
turnips, 40 days); (10) between russet and burnt umber (yellow turnips, 
40 days); (11) light burnt umber (white turnips, 49 days); (12) midway 
between burnt umber and mummy brown (yellow globe turnip, 50 days); 
(13) burnt umber (yellow globe turnip, 64 days); (14) sienna with a very 
slight admixture of brown (radish, 49 days); (15) dark brown (skin of 
yellow banana, 56 days). 

The formation of this pigment appears to depend on the presence of 
certain highly organized nitrogenous bodies — e. g,, albuminoids or pep- 
tones. Whether it is produced inside of the bacterial cell and dissolved 
out, or is formed in the substratum by the chemical action of colorless 
substances excreted from the cells, as seems more likely, could not be 
determined. Its formation also appears to depend on the presence of 
free oxygen, as in one instance, in an old culture on rutabaga (50 days) 
it was observed that the upper part of the substratum was distinctly 
browned, but in that part protected from the air (the lower one-half 
of the cylinder, in water grown full of the yellow slime and solidified) 
it was not browned. 

1\. steioarti grayed potato cylinders, but in two months it formed 
no brown pigment in tubes of radish, ruta})aga, or yellow globe turnip. 
In from 6 weeks to 2 months P.^. cnmpestris stained these same crucif- 
erous substrata various shades of l)rown — e. g., (1) raw sienna, (2) a 
color })etween russet and cinnamon rufous, (3) a color between vussct 
and tawny olive, (4) raw umber, (5) burnt umber, (6) dark burnt 
uml)er, (7) nuunmy brown. 

These brown pigments are also believed to be in some way connected 
with the presence of sulphur compounds and of taiuiins or related 
bodies in the plant or substratum, and with the formation of hydrogen 
sulphide and annuonia })y the bacterial organism. 



142 

As we have alread}^ seen, H.^S is given off promptly from coconut 
cultures of Ps. /ii/r/cinthi and Fs. campestris^ which do not become 
grayed or browned, and is not given off from potato or carrot cultures, 
which do become stained. 

A graying of steamed potato cylinders with subsequent pale brown- 
ing of the water in which they stand — viz, a change similar to that 
induced by many different sorts of bacteria — is readily produced by 
adding to the tubes a few drops of ammonium sulphide. Tannin, in 
the air, is oxidized readily to deep brown compounds when exposed 
to ammonia, but this change does not take place in vacuo neither did 
the potato cultures gray in vacuo. All bacteria or near^- all produce 
ammonia and hydrogen sulphide, and many vegetable substances con- 
tain tannins or allied compounds. 

A somewhat different result was obtained with Ps. 2)liaseoli^ which 
also grays potato cylinders and becomes dulled in color b}^ the forma- 
tion of a small amount of solu))le brown pigment. My attention was 
drawn especially to this by the behavior of some potato cultures. 
Eight of these were alike in their yellow color and Hie substratum 
was grayed; the ninth, while alike in all other cultural respects, was a 
much brighter yellow, and there was no distinct stain of the potato. 
At the time I had in the laboratory two stocks of potato made from 
different tubers. The question now arose whether the bright chrome 
yellow culture was specifically different from the wax yellow cul 
tures, or had been made accidentally on the newer potato stock and 
was the same species, but different in color on account of some slight 
chemical difference in the culture medium. To test this latter hypoth- 
esis a tube from each potato stock was now inoculated from the 
bright yellow culture. In one of these daughter tubes the growth 
was dull wax yellow, and the substratum was distinctly grayed withni 
48 hours. In the other the equally abundant growth was l)right 
chrome yellow, exactly like the culture from which it was made. 
There can be no doubt, I think, that the usual dulling of the slime of 
Ps. phaseoli on potato is to be ascribed to the absorption of a brown 
pigment formed out of some substance commonly present in the sub- 
stratum. These two cultures made from the bright yellow culture 
were tested for H2S on the fifth day by placing strips of lead acetate 
paper in the top of the tubes under the cotton plug. The paper in 
the dull yellow culture browned promptly. That in the bright yellow 
culture did not brown at all at first (24 hours), but finally browned 
feebly, corresponding to a slowly appearing feeble gray color in the 
substratum. When the cultures were 9 days old and the paper had 
been exposed 4 days the conditions were as follows: The tubes were 
alike in volume of growth and in general appearance, except as given 
l)elow. In one the color was a dull wax yellow, the lead paper was 
d irk brown at the lower end, the substratum was distinctly grayed, 



143 

and the bacterial slinie reacted inimediatel}' and distinct!}' alkaline to 
neutral litmus paper. In the other tube the color was bright yellow 
(gamboge), the lead paper was feebly browned (only about one-tenth 
as much as in the preceding), the substratum was very feebly grayed, 
and the bacterial slime reacted differently to the neutral litums paper — 
i. e., it was exactly neutral. 

Ps. 2>haseoU cultivated on 3^ellow and white turnips made a good 
growth, but no brown pigment was observed. On turnip-rooted rad- 
ishes the growth was also good and there was no brown stain for a 
month, but after that a slight stain appeared. 

NATURE OF THE CELL, WALL. 

The bacterial cell wall of Ps. hyacinthi stains yellow with iodine 
potassium iodide, and remains yellow on the addition of sulphuric acid 
(Russow's cellulose test). Tests were made with germs grown on agar, 
potato, starch jelly, etc. 

The bacterial slime from cultures on banana and sweet potato reacts 
blue with Russow's test. At first this was supposed to indicate cellu- 
lose in the bacterial wall. Subsequently ij was discovered that the 
blue reaction is due to some substance which may be washed away in 
water, the bacterial masses then giving only a yellow stain. This sub- 
stance, which reacts blue, is believed to form no part of the bacterial 
cell, but to be the dissolved substances of the su])stratum, carried up 
and held between the bacterial cells by capillarity. These experiments 
were repeated a year later with banana, using old cultures which bore 
a thick, dull yellow slime. This slime gave no blue reaction with 
iodine potassium iodide (absence of starch), but a very decided blue on 
adding sulphuric acid. Several washings in water greatly reduced the 
tendency to this blue reaction, but did not entirely prevent it. This 
was believed to be due to the fact that the water had not penetrated 
into the center of all the bacterial masses. The experiment was there- 
fore repeated as follow^s; Masses of the surface slime aggregating 30 
or 40 cu])ic millimeters, entirely free from fragments of the substratum 
(which contained undestroyed starch), were shaken in a beaker with 
150 c. c, of distilled water, and then put under an air pump for one- 
half hour, so ;is to remove air from the slime and permit penetration 
of the water into all parts. This water was then poured off', more 
added, and the exhaustion repeated. This second water was also 
poured off, more added, and the beaker again put under the air pump. 
After the third exhaustion there remained several hundi'ed small bac- 
terial fragments (zooglo^ie). As nmch as possible of the water stand- 
ing over them was then poured off and 4 c. c. of iodine potassium 
iodide was poured into the beaker and allowed to act for 20 minutes, 
during which time all of the fragments became yellow. To this fluid 
was then added 4 c. c. of the c. j). suli)iuiric-.acid water (2:1). In an 



144 

hour's time there was not the faintest trace of any bkie reaction, all of 
the bacterial fragments remaining yellowish brown. Some unwashed 
masses of bacteria, carefulh^ removed from the surface slime of one 
of these banana cultures, were now thrown into the beaker. Their 
surface immediately blued, and in a few minutes each one of these 
masses became deep blue throughout, forming a very striking con- 
trast to the 3'ellow stain in the washed particles. 

It may be that substances absorbed from the substratum into the 
bacterial layer will account for all of the few recorded cases of cellulose 
reaction in the bacteria. This possible source of error is certainly 
worth}' of very careful consideration. 

VITALITY. 

Length of Lifk ix Cultlke Media. 

No special attention was given to this subject, but from time to time, 
for various purposes, tubes of suitable culture media were inoculated 
from old cultures. The results show that Pa. kyacinthi is not readily 
destroyed by its own decomposition products. The nature and age 
of the old cultures in which this organism was still alive are given 
below: Feebly (litnms) alkaline potato broth, 24 days; beef broth 
neutral to phenolphthalein. with 5 per cent cane sugar. 32 days; mod- 
erately alkaline beef broth, with 10 per cent cane sugar. 79 days; acid 
(unneutralized) beef broth, 26 and 64 days; feebly (litmus) alkaline 
slant agar, 24 days; nutrient starch jelly, 31 days; sugar beet, 52 days; 
coconut, 59 days; white turnip, 41 and 80 days; radish, 80 days; gel- 
atin neutral to phenolphthalien, 38 days; gelatin alkaline to phenol- 
phthalein, i. e., —20 of Fuller's scale, 156 days: malic acid gelatin 
(acidity +54 of Fuller's scale), with 10 per cent cane sugar, at temper- 
atures ranging from 10- to 25^ C, 174 days. In a potato culture 91 
days old the organism was dead. It was also dead after 33 days in 
a beef broth made feebly alkaline to litmus by sodium carbonate. 
It was dead in 5 coconut cultures at the end of 2 years; it was dead 
on sugar beet after 2 years and 10 months; it was dead in 3 cultures 
on agar (stock 527) after 17i months. These results indicate that the 
orcranism is fairlv resistant, and also that it produces very little 

organic acid. 

Ph. campedris, BacillMS amylovm^us, B. catotmwnis,. B. pyocynnt^i^ 
pei'lcarditidis, and a green fluorescent germ which grows in the pres- 
ence of thymol, and which was isolated by the writer from one of Dr. 
Loew's tobacco infusions, were all alive on agar (stock 527) after 17i 
months. Ps. steicarti, on the contrary, was dead (2 tubes). Ps. 
phmeoli was also dead. All of these tubes were in the stock-culture 
box, subject to the same degree of cold (temperature 5- to 16° C), 
moisture, and darkness. Under similar conditions Ps. campestris was 



145 

alive on potato after 5 months and on agar (stock 553) after 10 months. 
Several tubes of Ps. phaseoli were alive after 5 months on potato. B. 
cmrjtovorus was also alive on potato at the end of 5 months. 

Resistance to Dry Air. 

Dr. Wakker states that the hyacinth organism remains alive in a dry 
state for a long time. Only three experiments were made to deter- 
mine this point, all of which tend to confirm his statement. 

(1) A typical potato culture 9 days old was shaken until nearly all 
of the yellow slime was washed into the 1 c. c. of fluid in the bottom of 
the tube. Fifteen small drops of this heavily clouded fluid was then 
spread on 15 small, clean, sterile cover glasses, in a Petri dish, the 
cover replaced, and the dish set away in a dry, dark closet, at 20° C, 
for 9 days. At the end of this time 13 of these covers were dropped 
into as many tubes of culture media — beef broth, sugared peptone 
water, etc. 

Result: Fs. hyacinthi developed after a few days in all of these 
tubes, showing that some germs were still alive on each cover glass. 
The time required to cloud these tubes was 3 to 8 days, at 16° to 20° C. 

(2) The remaining 2 covers were kept until the -ITth day, after which 
they were put into 1 per cent grape sugar peptone water. 

Result: After a few days the fluid in each tube clouded and threw 
down a yellow precipitate. 

(3) Some weeks later this experiment was duplicated, with the excep- 
tion that a period of 48 days was allowed to intervene between the 
spreading of the cloudy fluid on the covers and their submersion in 
the culture medium. In this instance the bacteria were derived from 
a 9-days-old culture on yellow banana, the slime being rubbed over 
the clean sterile covers, which were then set away as before. On the 
48th day 18 of these covers were seized with sterile forceps and dropped 
into as many tubes of sterile beef broth (stock 382) and set awav in the 
dark, at 20° to 26° C. 

Result: All but one of these tubes developed I\. hjacinth.L Nine 
clouded on the 4th day; 5 on the 8th day; 2 on the 12th day. Two 
tubes were clear on the ITth day, but one of these was cloudy on 
the 23d day. The other remained clear. These results seem to indi- 
cate a marked difference in the vitality of individual rods. These are 
the cultures Avhich were tested for invertase. 

Experiments with J\. campestrk and Ps, 2:)haseolh sho^v tliat they 
are also resistant to dry air, but apparently less so than Px. hyacinthi. 
The organisms were dried on cover glasses in a dark closet in the same 
way as P.^. hyacinthi, except that the temperatui'e averaged about 5° 
higher. The covers were inoculated copiously and wore side by side 
in clean covered Petri dishes. Of course those inoculated from the 
21788— No. 28—01 10 



146 

potato received the most bacteria. The tests were made from solid 
and fluid cultures and into two kinds of beef bouillon, viz: (1) Stock 
577, a standard salted peptonized beef broth +15 of Fuller's scale, 
which had dried out one-fourth b}^ long standing; (2) stock 579, a 
flask of stock 577 diluted with an equal bulk of distilled water before 
it was filled into the test tubes. When everj^thing was readj^ for the 
test, the dishes were brought out of the closet, and in clean, still air 
the inoculated covers were seized with sterile forceps and dropped one 
after another into the tubes of beef liouillon, which were then replugged, 
set away in the dark, and watched for six weeks. 
These experiments were as follows: 

(1) Ps. camjK'Stris. — Covers inoculated copiousl}' from the yellow 
slime on a potato culture 2 days old. Dry 31 days. 

a. Covers thrown into stock 577 — 12 tubes. 

Result: One tube clouded on the 3d day and one on the 1th day. 
The other 10 remained clear. The clouding was typical for this 
orp-anism, and cultures made from each of the tubes into potato yielded 
a tj^pical growth of Ps. camjjestris. 

h. Covers thrown into stock 579 — 12 tubes. 

Result: Six tubes were cloudy on the 3d day, 6 remained clear. 
The clouding was typical, and cultures from each of the 6 tubes into 
tubes of potato yielded in each case pure cultures of Ps. camjyestris. 

(2) Piu camj>estris.—^^Q\i cover inoculated with a small drop of 
moderatelv cloudv fluid from a beef broth culture 2 days old. Dry 34 
days. 

a. Covers thrown into stock 577 — 11 tubes. 

Result: No growth in any of the tubes. 

I. Covers thrown into stock 579 — 12 tubes. 

Result: Two tubes clouded on the 3d day. The rest remained clear. 
The clouding was typical, and transfers from the tubes into tubes of 
potato yielded pure cultures of Ps. campestris. 

(3) Ps. 2)haseoli.— Coy evs inoculated copiously with the yellow slime 
from a potato culture 3 days old. Dry 27 days. 

a. Covers thrown into stock 577 — 9 tubes. 

Result: One tube clouded on the 3d day, one on the 5fh day, and 
one on the 6th day. The rest remained free. The clouding was typical, 
and cultures from each tube into potato yielded a pure growth of 
Ps. 2>JHiseolL : 

I. Covers thrown into stock 579—12 tubes. 

Result: Two tubes clouded on the 3d day and 2 on the 4th day. The 
rest remained free. The clouding was typical, and cultures from each 
of the tubes into tubes of potato yielded a typical growth of Ps. 
jphaseoli. 

(4) Ps. i>liaseoJi.—Y.'AQ\y cover inoculated with a small drop from a 
well-clouded beef-)n-oth culture 3 days old. Dry 27 days. 



147 

a. Covers thrown into stock 5T7 — 12 tubes. 

Result: All clear to the end of the experiment. 

1). Covers thrown into stock 5T9 — 10 tubes. 

Result: No clouding in any of the tubes. 

Conclusion: In each case the transfers from potato did better than 
those from beef broth. The dilute bouillon appeared to be a more 
favorable medium than the concentrated. Ps. phaseoli seems to be 
less resistant to dry air than Ps. camjyestris. 

Resistance to Sunlight. 

The writer's experiments have not been very numerous, and the 
shortness of exposure absolutely necessary for the destruction of the 
organisms is not known, but probabh' it is considerably less than 
the time given below. The tests were made in poured plates of nutri- 
ent agar, which was inoculated copiously. The exposures were made 
in very thin-bottomed Petri dishes h^ing bottom up on larger Petri 
dishes filled with pounded ice. The exposures were made in Wash- 
ington in Ma}^. One-half of each plate was covered by several folds 
of thick paper and the other half exposed to the unclouded sun. A 
good-sized drop of well-clouded fluid was used in making each inocu- 
lation, i. e., many thousands of the bacteria. The bacteria in the 
covered portion of the dishes developed normally (except near the 
margin of the paper covering) as a dense uniform sheet of crowded 
small colonies. On the exposed part of each plate, and for some milli- 
meters beyond, nearly all of the bacteria were destroyed. The few 
that remained were tard}' in development and undoubtedly owed their 
escape to the protecting shade of less fortunate individuals. The 
exposed plates were as follows: 

1. Ps. hyacinthl. — 30 minutes' exposure; all killed. 

2. Ps. hyacinthl. — 45 minutes' exposure; all killed. 

3. Ps. cariipestris. — 30 minutes' exposure; 95 per cent killed. 

4. Ps. caiiipestrls. — 45 minutes' exposure; 98 per cent killed. 

5. Ps. i)haseoli.- — 30 minutes' exposure; 98 per cent killed. 

6. Ps. 2>haseolL — 45 minutes' exposure; all killed. 

The exposure was at niidda3\ The temperature of the plates during 
the experiment ranged from 24"^ to 27^ C. , i. e., w^as held down satis- 
factorily by the ice. In each case a considerable portion of the bacteria 
were killed under that part of the cover nearest to the exposed por- 
tion, i. e., over a width of one-fourth inch or more. On this part the 
colonies developed slowly at first, and, being fewer, had more room to 
grow, and became larger than on an}' other portion of the covered part 
of the plates. The covered part of each dish was turned south, i. e., 
toward the sun. 

Stewart found that exposure of I^s. stcwurtl in a portion of an agar 



148 

plate to bright sunlight for 3 hours destroyed nearl}' all of the organ- 
isms. In that part of the plate which was not exposed the yellow 
colonies came up thickly in 96 hours at 23^ C/ He does not speak of 
having tried the result of shorter exposures. Russell and Harding 
found that exposure of Ps. campestris in agar plates for 1.5 minutes to 
an August sun (latitude 13°) destro3'ed IH) per cent of all the organ- 
isms. Similar cultures exposed for 30 minutes to a November sun 
remained entirely sterile.^ 

Resistance to Heat. 

Ps. JiyacintJu is quite sensitive to heat, much more so than the 
bacterial parasites of the warm-blooded animals. To a less degree the 
same is true of Ps. ])l\cmedi and Ps. canqjestrk. See Temperature 

relations. 

Resistance to Acids. 

Ps. hyacintJn is quite sensitive to acids, being restrained from growth 
b}" comparatively small doses. It will tolerate more acid in a solid 
than in a fluid medium, and more of some acids than of others. See 
Malic acid gelatin and Sensitiveness to acids. In beef broth with 
malic acid +30 appears to be about its limit of growth. 

Resistance to Alkali. 

Ps. hyacinthi will grow in —25 gelatin and in —20 beef broth, but 
experiments have not been numerous enough to determine just how 
much alkali it will endure. In gelatin and beef bouillon —30 of Ful- 
ler's scale is probably al)out the limit of toleration of caustic soda. 

Growth in Presence of Calcium Sulphite. 

Ps. cam/pestris grew in 10 c. c. portions of galactose-peptone water 
with addition of 10 milligrams of calcium sulphite, but growth was 
distinctl}" retarded. The stock consisted of distilled water, \ per cent 
peptone, and \ per cent galactose. Other organisms were not tested. 

Growth over Chloroform. 

This test was made hj adding 5 c. c. portions of c. p. chloroform to 
10 c. c. portions of sterile alkaline beef broth in cotton-plugged test 
tubes. The beef broth was stock 382,^ well adapted to the growth 
of this organism. The chloroform settled at once to the bottom, but 

^ A Bacterial Disease of Sweet Corn. Bulletin 130. N. Y. Ag. Exp. Sta., Geneva, 
N. Y., 1897, p. 434. 

2 A Bacterial Rot of Cal^bage and Allied Plants. Bulletin 65. Ag. Exp. Sta., Wis- 
consin. Madison, Wis., 1898, p. 19. 

^1,320 grains minced lean beef and 2,000 c. c. distilled water in ice chest 24 hours. 
Steamed, filtered, resteamed, added water to make fluid 2,640 c. c. Titrated and 
found + 25. Added caustic soda to 0. A fermentation tube yielded 0.6 c. c. gas with 
B. coli. No peptone added. 



149 

on unplugging its odor was alwa^^s perceptible in the mouth of the 
tube. 

The chloroform exerted a marked retarding influence on Ps. hya- 
cinthi^ but did not always prevent its growth. The tube was first 
inoculated with two 3 mm. loops from a 10-days-old moderately 
cloudy culture in Diuiham's solution. In 24 days (at "KP to 25"^ C.) 
there was no growth. The tube was now reinoculated with two 3 
mm. loops of cloudy broth from a 3 -days-old culture in stock 382. 
After 12 days there was a faint surface clouding and a feeble partial 
rim of germs, which indicated that growth was proceeding with much 
difficult}'. A month later there was a good, dense, yellow rim, 2 nnu. 
wide, the fluid was well clouded, and on top of the chloroform there 
was a loose yellow bacterial precipitate about 2 mm. deep. 

For comparison with P.s. hyacinth I tubes of the same medium were 
inoculated with other organisms. Under the same conditions Ps.. 
camj)estris refused to gro^^'. The tube was first inoculated with two 
3 mm. loops from a 10-days-old moderately cloud}' culture in Dun- 
ham's solution. After 24 days, there being- no growth, the broth was 
reinoculated with two 3 mm. loops from a well-clouded 3-da3's-old 
culture in stock 382. After 43 days, there being no growth, the tube 
was inoculated for the third time with a 2 mm. loop of solid slime 
from a 48-hour growth on the surface of cooked turnip. This slime 
was broken up in the fluid by means of the platinum loop, and after- 
wards divided to a still greater extent bv shaking the fluid thoroughly. 
The tube was under observation for an additional 13 days, but no 
growth ensued. 

Ps. stewarti., on the contrary, grew in this chloroformed beef broth 
abundantly, with only slight retardation, and remained alive in it for 
more than 2 months. The tube was inoculated with one loop from a 
10-days-old culture in Uschinsky's solution. 

A number of other organisms behaved in much the same way as 
Ps. stevmrti^ i. e., the\' were more or less retarded for a few da3's, 
but afterwards made a more or less copious growth. Among these 
were B. amylovorvs., B. carotovomis., B. j^yocyaneus lyericarditidis., 
and B. coli. Ps. jj/uiseoh' grew slowly in chloroformed cane sugar 
bouillon Avhen inoculated copiously. 

MEANS OF DISTINGUISHING THE FOUR SPECIES OF PSEUDOMONAS. 

The four species of Pseudomonas may l)e distinguished as follows: 

1. Cruciferous plants — cabbage, cauliflower, kohlrabi, kale, rape, 
turnips. rutal)agas, ninstanls. I's. I'ajiijH'ntris. 

2. Legiuuinuus plants — Ijeans vi various kinds, e. g., lima beans, 
Found in , { bush beans. Ps. phaseoU. 

3. Liliaceous plants — hyacinths. Ps. hyacinthi. 

4. Gramineous jilants — maize, especially sweet corn. Ps. 
steinu-ti. 



150 



Growth on steamed 
potato cylinders 
standing in dis- 
tilled water. 



Growth in milk 



Growth in litmus 
milk. 



Growth on nutrient fl. 
gelatin and Loeff-| 
ler's l:)lood serum. i2. 
fl. 



Growth. on steamed 
yellow turnips or 
rutabagas standing 
in distilled water. 



1. 
Growth in milk or 

bouillon with 

ethyl alcohol. 

Behavior in tomato rl. 
juice and cabbagej 2. 
juice. ' 

Behavior in concen-il. 
trateil beel brothj 2. 
(acidity, -rSO) . I 
1. 

Behavior in Dun- 
ham's solution 
with indigo car- 
mine. 



Behavior in Dun- 
ham's solution 
with methylene 
blue. 



Copious and prolonged, covering the potato and filling the 
water with a solid yellow slime and changing all of the 
starch within a few weeks so that it does not react blue 
or red with alcohol iodine or iodine potassium iodide. Ps. 
campestris, Ps. phaseoli. 

Moderate and very little after the second week, not always 
covering all of the exposed part of the potato and never fill- 
ing the water with a solid yellow slime, the starch but little 
acted upon and always yielding (even immediately under 
the slime) a pronounced blue, blue purple, or red purple 
reaction. Ps. hyacintki, Ps. steirarti. 

The whey is slowly separated from the casein by means of a 
lab ferment; the casein slowly settles and after some weeks 
is partially redissolved. Ps. campestris, Ps. lihaseoli, Ps. 
hyacinthi. 

Growth good, but milk continues opaque and the whey never 
separates from the casein. Ps. stewarti. 

Blue litmus becomes gradually more and more alkaline. At 
no time is there any indication of acids. Ps. canipestm, 
Ps. phaseoli, Ps. hyacinthi. 

Blue litmus in course of some weeks changes to lilac or helio- 
trope, indicating the formation of a slight amount of acid. 
Ps. steirarti. 

A slow liquefaction, best in the order named. Ps. phaseoli, 
Ps. rampestris, Ps. hyacinthi. The latter brightest yellow. 

A good buff-yellow growth, but no liquefaction. Ps. steirarti. 

Copious in the air and filling the fluid with a thick yellow 
slime, which is not iridescent; substratum browned and 
softened. Ps. campestris, Ps. hyacinthi. The latter Naples 
yellow, the former paler yellow. 

Buff yellow, slightly iridescent, sparing (thin), and soon at 
an end, never filling the water with a solid yellow slime. 
Su})Stratum not browned or softened. Ps. steirarti. 

On 1 )oiling old cultures the steam yields an acid reaction and 
a fragrant smell. Ps. hyacinthi. 

No such acid reaction or odor. Ps. campestris, Ps. phaseoli, 
Ps. i^teirarti. 

Did not grow. P^. cainpestri.% Ps. phaseoli, Ps. hyacinthi. 

Grew copiously and for a long time without retardation 
(cabbage) or with only a slight retardation. Ps. .stewarti. 

No growth. Ps. campeMris, Ps. phaseoli, P^. hyacinthi. 

Retardation for some days, then a copious and prolonged 
growth. Ps. stewarti. 

No immediate reduction; color slowly changes to a pure 
bright blue, which persists for several weeks, but finally 
fades through green to yellowish. Ps. hyacinthi. 

No immediate reduction; color bluer for a few days only, 
changing to green and bleaching much sooner than the 
preceding. Ps. carnpeslri.-<, Ps. steirarti. 

Marked reduction; on shaking, a prompt reoxidation (to 
blue) ; final color the .same as at the beginning (pure blue); 
liacterial precipitate not stained. Ps. hyacinthi. 

As above, but the final color of the fluid green. Ps. campes- 
tris. 

No reduction, final color of the fluid blue; bacterial precipi- 
tate stained deep blue. Ps. steirarti. 



151 



Behavior in Dun- 
ham's solution 
with alcoholic so- 
lution of rosolic 
acid and a small 
amount of HCl. 



Behavior in chloro- 
formed beef broth. 



l1. Between the 6th and 9th day the pale orange yellow fluid 
changes to a geranium red, which gradually deepens to 
poppy red (37th to 56th day). Ps. campestris. 

2. The color changes follow the same general course as in the 

preceding, but much more slowly; i. e., no distinct change 
of color until after the 16th day and not so deep on the 
56th day. Ps. steivarti. 

3. The yellow color of the fluid gradually bleached and practi- 

calh'all gone at the end of the second week; no reddening 
of the fluid. Ps. hyacinthi. 

1. No growth. Ps. campestris. (Only one experiment.) 

2. Slow, long-continued growth, but with much difficulty iu 

ge':ting started. Ps. hyacinthi, Ps. phaseoli. 

3. Good growth, with little difficulty in getting started. Ps. 

stewarti. 



Behavior in distilled 
water containing 
4 per cent maltose 
and 4 per cent 
Witte's peptonum 
siccum. 



1. Fluid in old cultures (40 to 60 days) distinctly browned. 

cariipcstris. 

2. Fluid not browned. Ps. phaseoli. 



P.S. 



Growth on 10 c. c. 
slant nutrient agar 
containing 3 grams 
of cane sugar. 

Behavior on 10 c. c. 
slant nutrient agar 
containing 1 gram 
of grape sugar. 

Behavior on 10 c. c. 
of slant nutrient 
starch jelly con-< 
taining 500 mgs. of 
glycerin. 

Behavior on slant nu- 



1. No distinct retardation, surface smooth, slime cojiious, and 
generally wet enough to flow readily. Ps. campestris, Ps. 
phaseoli. 
Marked retardation of growth, surface roughened, reticulated 
or areolated, slime dry so that it does not flow. Ps. Iiya- 
cintJii. 

1. Growth copious, stimulated from the start. Ps. campestris, 

Ps. phaseoli, Ps. stewarti. 

2. Growth retarded for a week or more, ])ut finally better than 

in the check tubes. Ps. hyacimthi. 

1. Growth, after 24 days, copious, sirupy, bright yellow. Ps. 

campestris. 

2. Growth, after 24 days, much less than in the preceding or 

than in the check tubes, and with no distinct yellow 
color. Ps. phaseoli. 



trient starch jelly 
made with modi- 
fied Uchinsky's 
solution (see p. 63). 



Behavior in I^chin- 
skv's solution. 



Thermal death point 
(10 min. expos- 
ure iu beef bouil- 
lon) . 



1. Growth good, slime yellow, marked diastasic action. Ps. 

campestris. 

2. Growth much less abundant than in the preceding and slime 

very pale, marked diastasic action. Ps. phaseoli. 

3. Growth feeble, no diastasic action. Ps. hyacinthi. 

1 . No growth or growth long delayed and feeble, with appear- 

ance in the fluid of small, whitish, loose, wooly flocks. 
Ps. Jiyacinlhi. 

2. Growth retarded and feeble, zoogloefe compact, roundish. 

Ps. campestris. 

3. As in 2, V)ut a yellower and rather ])etter growth. Ps. 

phaseoli. 

4. An al)undant and long-continued growth — a very suitable 

culture medium. Px. steu-arti. 
{ 1 ) 53° C. Ps. stacarti. 



(2) 51.5° C. 

(3) 49.5° C. 

(4) 47.5° C. 



Ps. campestris. 
Ps. phaseoli. 
Ps. }u/aci)ithi. 



Brightest coloi- . 



152 

1. Generally wax yellow. Ps. campestris. 

2. Wax yellow to chrome. Ps. phaseoli. 
.- 3. Chrome yellow to canary. Ps. hyadnthi. The brightest 

yellow of the four. 
4. Buff yellow to chrome. Ps. sieimrti. 

K. B. — 01(1 cultures darken and stress must not be laid on slight differences in 
color at any age, since the yellow color of the same species varies according to the 
amount of brown pigment produced, and this varies with the medium and sometimes 
even with slight changes in the medium (see page 142). 

REMARKS OX THE YELLOW PSEUDOMOXAS GROUP. 

Characters ix Common. 

These bacteria agree in the following particulars: The\' are yellow 
rod-shaped organisms of medium size, straight or slightl}' crooked, 
with rounded ends. The segments multiph^ b}- fission after elongation. 
They are generally less than 1 /f in diameter. The segments are of 
variable length. As taken from the plant or from ordinary culture 
media, they are seldom more than three times as long as broad, and 
are often much shorter. The segments occur singly, in pairs or fours 
joined end to end. or in clumpy masses of variable size (zoogloese), 
more rarelv thev are united into long chains or into filaments in which 
no septa are visible. Endospores are absent or rare (none have been 
observed). The segments are motile by means of one polar flagellum, 
which is generally several times as long as the rod, and may be wavy 
or straight when stained. The species grow readily on all of the ordi- 
nary culture media, but so far as definitely known all require the pres- 
ence of air — i. e., are strictly aerobic.^ None are gas producers. All 
are sensitive to sunlight. All are quite resistant to dry air. They do 
not reduce nitrates to nitrites. As a rule, they are not easily destroyed 
by their own decomposition products. The yellow color appears to be 
a lipochrome. In the different species it varies from deep orange and 
buff-yellow, through pure chrome and canary-yellow, to primrose yel- 
low and paler tints. In the same species the yellow color also varies 
somewhat, being frequently changed, darkened, or obscured by the 
production of a soluble brown pigment, the amount of which pigment 
varies in different species, and in the same species on different media. 
Organisms parasitic in plants or saprophytic. 

As our knowledge increases it will, of course, be necessary to revise 
this characterization and probably to subdivide the group. Fs. cam- 
pestris and Fs. pluif^toU are nearly related; Fs. hyacintJil differs from 
the above very considerably, and Fs. steioarti is still further removed. 

^Note possible exceptions mentioned on pages 66, 67, and 71. 



158 

()tiii':k Steciks i!Ki,().\(iiN(; id iiii.s (iuonr*. 

The followiiiti;- species also Ix^lon^ to this o-i-oup and appear to he 
distinct from the foregoing, but our knowdedge of their cultural char- 
acters is more or less imperfect: 

(1) y^y. juglatidiK Pierce. Parasitic on the young nuts, leaves, and 
stems of Juglans raij'ia in C-alifornia. The cause of an economically 
serious disease in walnuts. Reseml)les I\. ('(iirqjedrls. Pierce does 
not mention having attempted to inoculate his organism into cruciferous 
plants, l)ut the writer has tried the reverse of this without success, 
viz, inoculations of /-!s-. campestrl^i and 7\ j^hast'oll into young rapidly 
growing shoots of the walnut (-/. r(^(ji<(). 

(2) P.H. vdsvularxuii (Cobb). Parasitic on sugai' cane in Australia 
and elsewhere. The vascular l)undles are filled with a yellow slime, 
the canes are dwarfed, and the sugar content is reduced. 

(3) Pf<. diiudld (Arthur and Bolley). Isolated from carnations 
(Dianthus spp.), and supposed to be the cause of a spot disease. Com- 
mon on the surface of carnation leaves, but now believed to be purely 
saprophytic. 

(4) Pa. amardnti n. sp. Occurs on species of Amarantus (weeds in 
tields) in the Eastern United States, tilling and l)rowning the vascular 
bundles and hollowing out the tissues in, their vicinity into closed cavi- 
ties tilled with this organism. The plants which are attacked ai'e 
stunted, droop, and dry up without any visible cause. The organism 
is a short rod and when grown on culture media has more orange in 
its pigment than any others here described. On the whole, it seems 
to ])e most nearly related to Ps. f<tevmrti 

(f)) Ps. iiKjlvacearum n. sp. Parasitic on cotton (Gossypium spj).). 
This organism causes the very characteristic leaf disease known as 
Atkinson's angulai' leaf -spot, and also a water-soaked spreading spot- 
disease of the capsules comi)arable to that produced on walnuts by 
Ps. jugJandls 'M\(\. on bean pods l»y Ps. 2)h<(><eoN. This bacterium has 
nearly the same thermal death point as Ps. cduipestrf's and much 
resembles it in many othei- ways, but its slime is more ti'anslucent on 
potato, and it is not parasitic to cab])age. The writer has had this 
organism under observation for several years, and has successfully 
inoculated it into young cotton ])olls and leaves. Tissues of the cot- 
ton plant which are not growing rapidly do not readily contract the 
disease. 'I'his yellow organism is not the same as the green tluorescent 
gei-m isolated })y Stinlman from rotting cotton capsules and named 
BaclJhis (jimypina. A full account of the cotton disease is in 
preparation. 

21788— No. 2S— 01 11 

O 



Bulletin No. 29. v. p. P.-83. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF YEGETABLE PHYSIOLOGY AND PATHOLOGY. 

ALBERT F. "WOODS, Chief. 



PLANT BREEDING. 



BY 



KfcW YORK 
^B O T A N I C A 



WIIvIvET M. HAYS, 

Professor of Agriculiure, University of Minnesota. 




WASHINGTON: 

GOVKRNMKNT PRINTING OFFICE, 
I 9 O I . 



OFFICE OF PLANT INDUSTRY. 

B. T. Galloway, Director. 

AFFILIATED DIVISIONS. 

Vegetable Physiology and Pathology, Albert F. Woods, Chief. 

Gardens and Grounds, B. T. Galloway, Superintendent. 

Agrostology, F. Lamson-Scribner, Chief. 

Pomology, G. B. Brackett, Chief. 

Seed and Plant Introduction, B. T. Galloway, Chief. 



DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 



SCIENTIFIC STAFF. 

Albert F. Woods, Chief of Division. 
Merton B. Waite, Assistant Chief. 

associates. 

Erwin F. Smith, Wm. A. Orton, 

Newton B. Pierce, Ernst A. Bessey, 

Herbert J. Webber, Flora W. Patterson, 

M. A. Carleton, Hermann von Schrenk,- 

P. H. DoRSETT. Marcus L. Floyd,-' 

Thomas H. Kearney, .Tr. 

IX charge of laboratories. 

Albert F. Woods. Plant Physiology. 
Erwin F. Smith, Plant Pathology. 
Newton B. Pierce, Pacific Coast. 
Herbert J. Webber, Plant Breeding. 



1 Special agent in charge of studies of forest-tree diseases, cooperating with the Division of 
Forestry of the U. S. Department of Agriculture, and the Henry Shaw School of Botany, St. 
Louis, Mo. 

2 Detailed as tobacco expert. Division of Soils. 



Bulletin No. 29. V. P. P.-83. 

U. S. DEPARTMENT OF AGRICULTURE, 

DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 

ALBERT F. WOODS, Chief. 



PLANT BREEDING. 



BY 



WILLET M. HAYS, 
Prof essor of Agriculture , University of Minnesota. 




WASHINGTON: 

GOVKKNMKNT PRINTING OKI'ICK. 
I 9 O I . 



LETTER OF TRANSMIHAL 



U. S. Department of Agriculture, 
Division of Vegetable Physiology and I^athology, 

Washington, D. C, January 38, 1901. 
Sir: I have the honor to transmit herewith the manuscript of a 
paper on phmt breeding, prepared l)y Prof. Willet M. Hays, of the 
University of Minnesota. Professor Hays has been engaged in plant 
breeding for a numl)erof years and has done mnch to arouse an inter- 
est in the subject tliroughout the country. The Department of Agri- 
culture, through its laboratory of plant breeding, several years ago 
actively took up the investigation of plant-breeding problems, and 
much work has been done in the improvement of cotton, corn, Avheat, 
oranges, pears, grapes, etc. Results of great importance liave already 
been obtained, and several ]iapers treating of important factors of 
plant breeding liave been published in bulletins of tliis Division and 
in the various Yearbooks of the Department of Agriculture since 1897. 
Tlu; pi-esent pai:»er is of special interest to experiment station workers 
and otliers engaged in similar lines, and I respectfully recommend its 
[)iil)licati<)n as lUilletin No. 29 of this Division. 

KespectfuUy, Albert F. Woods, 

C hief of Division. 
Iloji. James Wilson, 

Secretarij of Ayr- ic til I are. 



CONTENTS. 



Page. 

Intro ".uetion _.... . ... .. 7 

General observations on plant breeding; 10 

Relaiiou of plant breeding to wealth _. 10 

Examples of results of breeding _... 13 

The "Wealthy Apple . 13 

The race horse, Messenger 13 

Minnesota No. 169 wheat _. .. . 14 

The value of large numbers in breeding experiments _ . 15 

General facts concerning heredity .. ... 16 

The use of variation illustrated 17 

Records and score cards 24 

Percentage score cards ., 25 

Graphic score cards _ 27 

Methods of plant breeding ...... . 28 

Relation of plant introduction to plant breeding 2S 

Choice of foundation stocks . , 30 

Names and numbering of varieties 31 

Breeding by selection . .. . _. 33 

Sele'^tion of seedling plants 33 

Bud selection . . . . , 3.5 

Breeding by hybridization and selection 37 

Degree of relationship in crosses .. .. . 38 

Hybrids and crosses defined .... . 40 

Im])ortance and methods of hybridizing. 40 

Breeding for special and new uses ^ ... 41 

Breeding nitrogen into field crops. .. ._.... 42 

Illustrations of work in plant breeding 44 

Breeding wheat . . .... . 44 

Improvement by selection alone, 44 

Wheat flowers.. .. _. 50 

Formation of varieties by hybridizing. ... 50 

Experiments in wheat breedinir . 54 

Hybridizing as a cause of variation in wheat 56 

Breeding corn . 57 

Selecting seed corn .. . 58 

Hy])ridizing varieties of corn ... 60 

Breeding timothy 61 

Brei 'ding potatoes . .. . 63 

Breeding apples 64 

How to hybridize apples 65 

Breeding black walnuts. 68 

Breeding fla.\ 69 



ILLUSTRATIONS. 



PLATES. 



Patre. 



Pr.ATE I. Fig. 1. — TeshnLT the g.ntcii of new wheats as to its amount and 
savngth: Fig. 2. — Making the bakers" .sponge test of 

new varieties of wheat ... _ 28 

IT. Fig. 1. — Improvement of flax by selection; Fig. 2. — Planting 

seeds in the crop nursery . , . . . __.... 34 

III. Fig. 1. — Two centgener plats of wheat; Fig. 2. — Men emasculating 

and cross-pollinating wheat ......... 46 

lY. Fig. 1. — Harvesting twentieth-acre plats of wheat: Fig. 2. — 

Thrashing and cleaning wheat from centgener plats . 48 

V. Mi ling samples of wheat . .... .. ..._ ... 50 

VI. Fig. 1. — Si)ikes of parent and hybrid wheats: Fig. 2. — Spikes of 

timothy, showing improvements by selection . 56 

TEXT FIGURES. 

Fig. 1 . Graphic e.xpression of Quetelet's law 1 . 18 

2. Yields in grams of 80 Powers Fife wheat plants, arranged in order 

as numbered . . ...... . . . . . . 18 

3. Y'ields in grams of 80 Powers Fife wheat plants, arranged in order 

of yield . .. 18 

4. Yields in gi-ams of 80 plants of Blue Stem wheat, arranged in order 

as numbered . ...... 19 

5. Y'ields in grams of 80 plants of Blue Stem wheat, arranged in order 

of yield. .. .. .. 19 

6. Yields in grams of 86 Fife-Blue Stem hybrid wheat plants, arranged 

in order as unmV)ered . . ... ..... . .. .. 19 

7. Yields m grams of 86 hybrid wheat plants, arranged in order of 

yield ... - . . .... . . 20 

8. Y'ields in grams of 100 Blue Stem and 100 Fife wheat plants com- 

pare i - - .- - - . 

9. Yields in grams of 100 plants each of Fife, Blue Stem, and a hybrid 

between the two. . . _ .. . . 21 

10. Yields in grams of Fife. Blue Stem, and hybrid plants alter further 

selection _ . . ._...._. . . 22 

11. Yields in bushels of 10 new strains of wheat ... 23 

12. Graphic score card comparing wheats . 26 

13. Scheme of jilanting wheat in field crop nursery 45 

14. Method of preserving record sheets .._.._ .....--,. 49 

15. The spikes, flowers, and seeds of wheat. .. . ... 51 

l''«. 0[>eMiug of wheat flowers and anthers . . 52 

1 '. . Removing the flowers of the smaller and later spikelets . 53 

1 N. Opening the floret to remove the anthers 53 

1 '■). Gi'aphic expression of the results of an experiment 57 

20. Floral organs of timothy 62 

21. Flowers of flax - 70 

6 



PLANT BREEDING 



INTRODUCTION. 

Much seieiitific tliought has been centered on fertilizing the soil that 
tlio lai-gest possible returns niiglit be se<3ured from a given amount of 
labor and expense. Man has been slow to recognize tliat plant life is 
in a wondiM'ful manner subject to his control. There lias been a con- 
trolling pliilosophy connected with botanical thought which has held 
too closely to tlu^ doctrine of the immutability of specnes in plants. 
The systematic botanist held the species so close to our eyes that the 
mol)ile chai-acter of the plants was not generally recognized. That 
"like begets like" is an important fact; but it is of greatest impor- 
tance wlien used to intensif^^ or fix vari^itions of peculiar merit that 
these variations may be multiplied and thus become the basis of 
improved varieties. The results of breeding and the science of breed- 
ing have come forward slowly and unobti'usively. Their significance 
has not been fully appreciated. In view of the great results from 
breeding which have already appeared, it is safe to assume that per- 
sistent systenuitic effort will bring improvements that are now gener- 
ally deemed impossible. 

In any country there are very many localities each with its special 
conditions and needs. Each locality' uses not a few, l)ut many, sjiecies 
and varieties of plants, each suited to the particular soil, climate, and 
othei- conditions. Now tliat the creative work of plant breeding has 
been taken up by many scientific workers in State experiment sta- 
tions, the national Department of Agriculture, and by many seed 
firms and individuals, variety formation and scientific breeding are 
])()iiii(l to develop very i-apidly. The suggestive work of Charles Dar- 
win is ati last vivif5ang the dormant ideas concerning breed and vari- 
ety formation. Weismann and others who study hei-edity will con- 
tinue to be heard with interest; and those who are studying methods 
of plant l)reeding to increase production will be lieard in proportion to 
the economic and artistic value of their products and to the scientific 
value of their theoretical discoveries. Many of the facts relating to 
heredity are not only of great interest but of great value to the breeder. 
The study of the cell iind (tf enil)ryolog3' '^ adding knowledge of 

7 



8 PLANT BREEDING. 

exceedingly great value to the breeder. Tlic known facts of animal 
and i)lant bi-eeding, largely wrought oiit in extensive practice, and 
the visible results of the work of those who breed plants and animals, 
are for the present of paramount economic importance. Tliey give 
the basis for a most valuable philosophy, because simple and useful. 
Plant breeding in America is very much underdone, and in many of 
its lines public money invested in experimental work may be made to 
yield to the country a hundred or a thousandfold. The literature of 
the subject of plant and animal breeding has not been as hopeful in 
tone as the achievements and the great imj^ort^uce of the subject 
have warranted. 

The knowledge of the subject of breeding has not been well classi- 
fied, nor has it been properly emphasized. There are a few books, many 
scattered articles, and numerous statements in the general writings 
of many men. Charles Darwin, in his work on " Variations bf animals 
and plants under domestication," and other writings, brought together 
a large collection of facts and a most original philosophy of heredit}^ 
and variation. He recognizes the force of facts shown by improve- 
ments which men had achieved in breeding plants and animals. J. H. 
Wallace, in Volume II of Wallace's American Trotting Register, and 
in other writings; J. H. Sanders, in his book on Horse Breeding; 
Manly Miles, in Stock Breeding; and other American writers on animal 
breeding, have shown that they in part conqirehend the force of Dar- 
win's philosophy as relates to animal and plant breeding. Prof. L. H. 
Bailey and other recent writers have done much to arouse an interest 
in breeding plants. The plant improvements of most marked promi- 
nence are recent, and the men who have done tlie best work have 
written but little. They have worked with plants rather than with 
the written theories. The theorj^ of many writers gives less encour- 
agement for far-reaching results than the facts Avarrant. The long 
time required to produce considerable changes in the species and 
varieties of useful plants has had a very retarding effect upon prog- 
ress in this line of work. Results of immense economic importance 
which have already been attained should be shown in their true light. 
Where the individual can not afford to wait for results and will there- 
fore not properly Garry- forward v^ariety formation, it is the duty of 
the State to assume the work. The length of'time required to breed 
special varieties of each class of economic plants suited to each local- 
ity should not, henceforth, prevent the expending of much effort in 
this direction. 

Besides being a subject of vast economic importance, the breeding 
of plants is a fascinating study and a most enchanting pastime. It 
is one of those subjects in which students like to specialize. Students 
in the writer's college classes, as soon as they gain a place to work in 
the field-crop nursery and seed house, wish to forego specializing in 



WORK OF SEEDSMEN, 9 

other subjocts and concentrate their energies on this fascinating- and 
prod net ive work. In looking toward the fnture, it seems probable 
that plant l)reeding will receive far more attention than heretofore. 
In Enropean countries much more attention is given to the improve- 
ment of i^lants-than in America. In two towns in Gerraanj^ there are 
nearly 30 large seed firms, with an aggregate capital investment prob- 
ably five times as great as the capital of the general seed firms of 
America. In that country owners of large farms breed and raise 
seeds of wheat, oats, i-ye, sugar beets, potatoes, and other crops. They 
get better profits from tiiis M'ork, and they build on tlieir farms chem- 
ical and seed laboratories where the seed selection is done systemat- 
ically. Those farmers to whom they su^iply seed which will make 
their jaelds larger are also benefited. 

In England, the average yield of wheat is over 30 bushels per acre, 
while in the United States it is below 15 Imshels. This difference is 
in part due to the better prejjaration of soil and the moister climate; 
but doubtless it is also due in part to the selection and breeding of 
wheat during a much longer period than has passed since wheat Avas 
first grown in this new eountiy. 

Dr. Rimiaau, Mr. Haine, Mr. Strube, and other farmers of Germany, 
which country I had the pleasure of visiting recently, find that seed 
growing and l)reediug is a verj'^ practical vocation. They breed wheat 
in a manner somewhat similar to the plan described in the following 
pages, and they employ system and precision in the selection of indi- 
vidual plants and of resulting varieties. Mr. L. H. Ilaynes, of Fargo, 
N. Dak., has done much careful work in breeding wheat, and has 
made greater profits from his farm than if he had raised the standard 
varieties of wheat for the market. 

Breeding plants, since the literature on the subject is growing in 
volume, gives opportunity for wide study. Especiallj' as an art does 
the breeding of plants give the opportunity for the develoijment of 
skill of a high order. The breeders of plants, as well as tlie breeders 
of aninuils, need to make more of a study of records, of relationships; 
in a word, design, collect, and study pedigrees of the plants and ani- 
mals with which they deal. 

In many cases amateurs who have followed up accidental forms of 
value have sold them to dealers at good prices, and some amateurs 
breed phiiits according to a carefullj- considered system, making a 
profit foi- themselves and at the same time pi-oducing valual)le varie- 
ties for cuilivatiou. Uriglit young farmers can not undertake work 
which is better calculated to add interest to their cho.sen busine.ss tlian 
to become breeders of pedigree plants or animals. Seedsmen depend 
largely upon amateurs for new and valuable varieties, and they are 
always ready to pay good prices for useful new sorts. The seedsmen 
of America have not kept pace with European seed firms in variety 



10 PLANT BREEDING. 

formation, nor even in keepinj? np and improving old forms. They 
have liere a most legitimate field; unless they develop tliis feature, 
they remain only seed merchants, and can hardly hope to gain that 
position in the minds of purchasers which they should hold to have 
the most profitable seed trade. 

Plant breeders need not work along nan-ow lines nor follow set 
rules. There are many ways of conforming to tlie broadly applicable 
principles of producing, finding or discerning, fixing, and multiplying 
desirable variations. The devices of each plant breeder will solve 
the problem for his environment and for the objects he seeks. Plans 
outlined to suit the needs of one may not wholly meet the require- 
ments of another situated differently. 

The great system of American experiment stations has fairly begun 
the work of variety formation in important plants. We can, there- 
fore, hope for the subject to be gradually placed upon a thoroughly 
scientific basis. 'J'here is room and need in this line of work for the 
best energies of all the agencies, amateurs, seed growers, seed firms, 
and experiment stations, including that largest one, the national 
Department of Agriculture. 

The writer is under obligation to Mr. Andrew Boss, assistant in 
agriculture in the University of Minnesota, and to gthers who have 
assisted in the experiments (as yet not all reported in station bulle- 
tins) upon which this paper is in part based; also to student assist- 
ants who have aided in preparing the illustrations. 

GENERAL OBSERVATIONS ON PLANT BREEDING. 
RELATION OF PLANT BREEDING TO WEALTH. 

The economic results from plant improvement are already enormous 
in the aggregate, and the possibilities for the future are so great as to 
be truly dazzling. Circular No. 11, recently issued by the Division of 
Statistics of the U. S. Department of Agriculture, for example, esti- 
mates the world's wheat product for 1899 at over 2,500,000,()(){) Imshels. 
Assuming the yield to be 20 bushels per acre, this required 125,000,000 
aci-es of land. In ten years the Minnesota station, by careful breed- 
ing, produced a new variety of wheat, which yielded nearly 25 per 
cent more grain on the university farm than its parent varietj', which 
was the best variety generally grown in the State. The following 
table (Bulletin No. 62, Minnesota State station) shows comparative 
yields of the new and the parent variety on several experimental 
farms. In the last two columns appear the average results obtained 
in five successive seasons at the university farm, near Minneapolis. 
It should be observed that this new variety has not proven so much 
superior in yield to the parent variety on other experimental farms a 



RELATION OF PLANT BREEDING TO WEALTH. 



11 



few liundred miles distant, which emphasizes the ueed of breeding' 
varieties for each locality: 

Minnesota No. 160 comx)ared with, its parent variety, Minnesota No. 51. 



Where grown. 


Season. 


Yields per acre. 


Yields per acre at 
university farm. 


Parent 
variety. 


New 
variety. 


Parent 
variety. 


New 
variety. 




1895 
1896 
1897 
1898 
1899 
1898 
1899 
1898 
1898 
1898 


Bushels. 
31.6 
34.6 
20.4 
23.3 
3.5.9 
23 
11.7 
33.5 
30.2 
8.8 


Bushels. 
37. 8 
3.5.0 
34.3 
36.3 
28.8 
19.3 
13. 4 

as. 4 

14.1 
13.5 


Bushels. 
31.6 
34.6 
20.4 
33.3 
35.9 


Bushels. 
37.8 


Do -- 


25.0 


Do , 


24.3 


Do . 


26.3 


Do - .... 


28.8 


"N'oi'tliftast, fai'iTi 




Do 






!N^orth Dakota 






South Dakota . - 






loWtl 














21.3 


34.0 

2.7 


33.2 


28.5 


Gain 




5.3 













Twenty-five per cent, or 5 bushels per acre, increase would add to 
the world's snpply of wheat 025, 000. 000 bushels. This, at 80 cents 
per bushel, would be valued at 1500,000,000 for each year. If by 
T)reeding' we can increase yields only so much as 5 per cent, or 1 
bushel per acre, we will still have an increase of $100,000,000 per 
annum, or 1,250,000,000 bushels increase in the world's crop in ten 
3'eai-s. Since the United States jjroduces about one-fifth of the world's 
wlK^at supply, an annual increase of 1 bushel per acre would result in 
ten years in an increased valuation of $200,000,000 for this country. 
One-tenth of 1 ptM' cent of this sum spent in wheat l)reeding would 
doubtless be more than sufficient to produce a much greater increase 
than 1 bushel per acre. The writer's interpretation of the facts con- 
cerning the pi-oduction of numerous new varieties of wheat in Minne- 
sota by selection, aided by occasional hybridizing, is that 25 per cent 
increase in yield is a conservative estimate of what it is practicable 
ul1imat(dy to accomplish in that State in the improvement of wheat 
by bi-eeding. Several decades will be required to accomplish this, 
and the proof is now nearly conclusive that breeding, or at least 
variety testing, must be done for each general locality within the 
State. 

The breeding of corn in the United States has I'esulted in a very 
mai'ked improvement of that crop. In nearly every county there are 
varii^ties or sti-ains specially suited to local conditicms. Formerly 
those d(^nt vari(^ties which yielded large crops of grain were adapted 
only to the Southern and Middle States. Now dent varieties ai-e found 
maturing large crops nearly to the center of the nortlnM-nmost tier of 
States. Through selection the farmers of the Northern States liave 
greatly increased the yields of thcMi- cornfields. Corn being such a 
larger plant that each ear is taken in the hand in husking out the crop, 



12 PLANT BREEDING. 

the farmer has been al)le to choose the very best yielding plants out 
of immense fields. Without fully recognizing tlie fact, the farmers 
of America have been conducting with corn the most extensive breed- 
ing experiment ever carried on. 

Corn being an open fertilized species, large numbers of new forms 
have resulted from accidental hybrids between different varieties in 
adjacent fields, thus forming many local varieties of this very iiitei- 
esting plant, and building up the yield and quality of the corn crop 
of America. 

If the corn crop of the United States were reduced to 80 j)er cent of 
its present yield we would have 1,600,000,00.0 instead of 2,000,000,000 
bushels, or an average of 20 instead of 25 bushels per acre. What 
farmer would think of returning to the smaller ears of fifty or one 
hundred years ago? Yet it is quite possible in another half century, 
by more careful breeding and with greater attention to the composition 
and quality of our corn, to make as imjiortant improvements as have 
been made in the past. It is probably safe to say that the farmers, 
by adding 25 per cent more to tlie care and lal)or of rotating crops, 
manuring the soil, and cultivating the corn, could secure 25 per cent 
larger yields. And it is probably just as safe to say that if one-tenth of 
1 per cent of the corn crop's value were devoted by tlie Government to 
breeding this plant so as to better adapt it to each locality, 10 perceiit 
more coukl be added to the yield. Wliih- better farming and better 
cultivation are ultimatelj^ the moi'e important in tlie aggregate, plant 
breeding is relativelj' more important until our crops are brought up 
more nearly to their possible maximum of jield. 

Our ten leading field crops in tlie United States yield an annual 
income which is valued on the farm at something like !^2, 000, 000,000. 
No man who has earnestly and intelligently tried to increase the 
yields of any one of these crops will doubt the assertion that bj' breed- 
ing alone, other conditions remaining the same, an average increase 
of 5 per cent could be added to the jaelds of these ten crops in twenty 
years by a line of thorough experimentation. Prices remaining the 
same, this would add 1100,000,000 annually to the aggregate valuation 
of these crops; or, in twenty succeeding j^ears, $2,000,000,000. If to 
the increase in value of our principal field crops are added the increase 
in values of orchard, garden, greenhouse, and forest crops, we will 
have a much greater aggregate gain. All these crops are capable of 
improvement bj^ breeding, the same as corn and wheat, and the gen- 
eral principles to be followed are the same throughout. In manj- ol 
the flower and vegetable crops changes have already been produced 
bj^ breeding that are far greater than the anticipated changes in the 
yields of corn and wheat. 

In the ease of sugar beets, for example, the percentage of sugar in 
the juice of the roots has been increased probably 100 per cent by 
rigid scientific methods practiced on a large and expensive scale by 



RESULTS- OF BREEDING. 13 

European seed growers. This work, started by Vilmorin of France, 
has made possible a large industry, profitable to the farmers and to 
manufacturers, and has resulted in much cheaper sugar for the entire 
world. Here, as in other lines of breeding, the principles and practice 
are comparatively simple and easily mastered. Remove it from the 
domain of abstruse reasoning, where some teachers of heredity place 
it, and plant improvement becomes a practical business proposition, 
an important affair of state. 

EXAMPLES OF RESULTS OF BREEDING. 

Three illustrations from plant breeding and from animal breeding, 
in which the general principles are the same, will suffice to emphasize 
the simpler side of the question of improving our useful plants : 

THE WEALTHY APPLE. 

The Wealthy apple, originated by Peter M. Gideon, of Minnesota, 
will serve as the first illustration. Mr. Gideon planted many apple 
seeds and watched the seedling trees develop. Most of the young 
plants succumbed to the severe Minnesota winters. One plant stood 
out prominenth'^ as being very hardy, and as the years passed it grew 
to a fruitful tree. Its fruit was fine in appearance and of superior 
quality. Mr. Gideon grafted some of the scions on other trees, and 
others he grafted on seedling roots, making independent trees. True 
to the nature of the apple tree, all these cuttings grew and bore fi-uit 
like that of the seedling plant. Mr. Gideon gave trees to his horti- 
cultural friends, and, being a nurseryman, sold many to his customers. 
This variety of apple now stands as a testimonial to Mr. Gideon's 
usefiilness. He since has added a number of other useful hardy 
varieties to the apple list of the middle Northwest. The Wealthy 
apple, being the first prominent i^roduct of the efforts at breeding 
a hardy race of apples for the section of countrj^ mentioned, has a 
peculiar intenist. As is often asserted, this apple, considered merely 
as a fruit i)roduct, may be worth more than a million dollars, but its 
value as an (jncoui-agement to apple breeding, and to plant breeding 
genei-ally, is far greater. There are now being bred in Minnesota and 
sui-rounding States very many new varieties of apples from hardy 
l^arents. 

THE RACE HORSE, MESSENGER. 

Messenger, an imported English race horse, whi(*li became the lead- 
ing i)r<)genitor of the American race of trotting horses, will serve as 
the second illustration. In nearly if not quite all of the best indi- 
viduals of this great breed there is some of the blood of this horse, 
fanu)us, not for his individual performance, but because of his power 
to transmit to so great a pi-ogeny the al)ility to win trotting races. 
This ability to trot is made up of many correlated elements, such as 



14 PLANT BREEDING. 

the instinct to contest the race, t lie form of body which permits light 
and free action, the textnre of every bone, fiber, and nerve, and the 
teacliable nature which enables the trainer to educate the horse. A 
combination of all these characteristics was given to this race of horses 
by the parent horse. Many other running horses have been employed 
in- efforts to i)roduce a competing strain of trotters. But the blood 
of Messenger stands above them all. And his descendants, through 
rigid selection extensively practiced, are gaining in trotting ability 
from year to year. He was a chance discovery. With the element 
of variation once in hand, the horsemen of America have gone on 
improving and intensifying it and reducing the American trotters 
to a uniformly fast-trotting race of animals. 

MINNES(JTA NO. 109 WHEAT. 

One of the varieties of wheat originated by the Minnesota experi- 
ment station will serve as the third example. This wheat, mentioned 
on a previous page, was originated from a single plant (No. 476, of 
1892) in the following manner: Several of the best plants were chosen 
from among 400 plants of Blue Stem, each growing separately, a foot 
apart each way. Each of the selected plants yielded 500 or more 
grains of wheat weighing 10 or more grams. The seeds from each 
chosen plant were planted for a few years until sufficient seed was 
obtained to plant a field plot. Then for several years each of the new 
strains was grown in a field beside the parent variety from which the 
400 original seeds were chosen. A few of tlie new strains proved 
superior to the parent variety, but the one named Minnesota No. 1G9 
stood out so preeminently superior that all others were discarded. 
For a large area of Minnesota this wheat seems capable of yielding 
at least 1 or 2 bushels per acre more grain than its parent variety, 
which is the best kind commonly and ahnost universally found on 
the farms in southern and central Minnesota. This variety in ten 
years could be increased so as to almost displace the parent wheat. 
The peculiar quality or power in the single germ which was the 
parent of plant No. 476 in our field crop nursery in 1892 had a very 
great value. Tlie system which was followed to find the germ of 
greatest value is comparatively simple. The cost of finding this plant 
and of developing a variety of wheat from it, including the cost of 
forming and testing all the strains which failed to reach first place, 
was probably not one-thousandth of the value of this new wheat. 
The production of this and other similarly useful new varieties gives 
courage to experimenters, and warrants the State in investing more 
money in similar experimentation with wheat and other important 
crops. 

The purpose of this pap6r is to show the importance of plant breed- 
ing to the country and. to the farmers and gardeners, and to throw 
out into clear light its important practical features. The great ques- 



IMPORTANCE OB^ BREEDING ON LARGE SCALE, 15 

tioii is, llow can we get results? If a sinj^le genu has such wonder- 
fully far-reaching power and immense value, as in the instances men- 
tioned above, we want to know two important things: (1) IIow shall 
germs with the special values be produced? (2) How shall we select 
them out of the large number which must be grown to secure the 
superior one? 

THE VALUE OF LARGE NUMBERS IN BREEDING EXPERIMENTS. 

The history of breeding animals and plants has many lessons, only 
a portion of which are as yet read understandingly. The English 
bi-eeder of hounds expressed a most important truth when answering 
an incpi iiy as to the secret of his success. He said : "I breed many 
and I hang many." Only the ver}' few of highest value out of many 
were used as the foundation stock for furt