158 
THE EMPLOYMENT OF DISEASE-CAUSING MI- 
CROBES FOR THE DESTRUCTION OF FIELD 
MICE, MOLES AND SIMILAR VERMIN. 
BY GERALD M’CARTHY, N. C. AGR. EXPT. STATION. 
Tue loss annually caused by field mice, moles, gophers, 
hares and other rodents, is in the United States an indefi- 
nite quantity, but must in the aggregate amount to several 
millions of dollars. In California and Colorado the jack- 
rabbit, Zepus Californicus, and sage rabbit, Z. artemisia, 
are very serious pests, while in the eastern states Z. 
sylvaticus, the cotton tail, and ZL. palustris, the swamp 
coney, are depredators in grain shocks and growing 
crops. 
The gophers, Geomys, and other genera, are very 
destructive in the. grain fields of the arid West. The 
damage wrought during winter by gnawing mice and hares 
in the orchards of the eastern states is a matter of no 
small consequence to fruit growers, and nursery-men and 
gardeners raise a continuous howl against the ground 
mole. 
The damage caused in Australia by the introduced 
rabbit is enormous—almost exceeding belief. In Europe 
the worst pests of the rodent family are the common field 
mice, Arvicola arvolis and Mus sylvaticus, called in France 
campagnols and mulots, respectively. 
How to destroy these vermin on a large scale and over 
wide areas, without destroying at the same time useful 
animals, has recently engaged the attention of many 
European scientists. In the United States the use of 
poisoned grain, and more recently of carbon bisulphide 
for the burrowing species, has given the most satisfactory 
results, but in various countries of the Old World the 
employment of pathogenic bacteria for this purpose has 
given a gratifying success. 
In a paper recently presented to the French Academy 
by M. Jean Danysz, a destructive, spontaneous epidemic 
among these animals in the Commune of Charny is 
described in detail, and experiments reported to show 
that while highly contagious and fatal to all small rodents, 
it is quite innocuous to cats, dogs, fowls, domestic 
animals and human beings. ‘The specific bacillus was 
isolated by the culture method and was subsequently 
employed on a large scale to destroy the vermin infesting 
an area of about seventy-five hectares. The whole number 
of rodents infesting this space was calculated at from 
10,000 to 30,000,—Ayvicola arvolis being in the majority. 
The process of infecting the field with the pathogenic 
germs was substantially as follows: The contents of ten 
dozen of gelatin culture tubes containing the bacillus 
were dissolved in fifty litres of water, and in this was 
soaked about 80,000 cubes of bread of about 1 c.c.m. 
The bread was then scattered throughout the field, a 
morsel being placed near every hole showing recent traces 
of an occupant. The operation occupied twenty persons 
two hours daily, from four to six P.M., for three consecu- 
tive days. The total cost of the treatment amounted to 
about 3 1/2 francs per hectare, or about thirty cents per 
acre. Within three days after the distribution of the 
infectious bread, sick and dying mice were plentiful in the 
field, and autopsies of several showed the presence of the 
microbe in their blood. The bread was distributed over 
the infested fields September 29 e¢ seg., and on October 15 
scarcely a living mouse could be found in the infected 
area, though abundant enough in neighboring non-treated 
fields. Opening the burrows of the rodents showed their 
galleries to be filled with dead mice. : 
This same process was tried in several other depart- 
ments of the republic, and always with similar success, 
insomuch that the author concludes that in this microbe 
SCIBINCIE. 
Vol. XXIII. No. 58 
farmers whose fields are infested by gnawing rodents have 
a simple, inexpensive and certain remedy. 
The identification of the bacillus is not given in the 
paper referred to, but is promised in a future communica- 
tion to the Academy. ‘The author states that it is very 
similar to the bacillus of duck cholera, but not identical, 
nor are ducks or other fowls susceptible to the disease. 
SCIENTIFIC WASHINGTON. 
THERE are now seven associated scientific societies in 
Washington, having a combined membership of 1524, 
comprising 1138 persons. These societies and their 
membership are as follows: 
Anthropological, 205; Biological, 190; Chemical, 102; 
Entomological, 38; Geographic, 619; Geological, 137; 
Philosophical, 233. These numbers indicate the active 
resident membership: there are in addition 472 members, 
a few honorary, the remainder active, though residing 
elsewhere. 
These organizations include many men eminent in 
science and in official life. Among officials are Hon. 
H. A. Herbert, Secretary of the Navy; Hon. J. Sterling 
Morton, Secretary of Agriculture; Major J. W. Powell, 
Director United States Geological Survey; T. C. Men- 
denhall, Superintendent United States Coast and Geo- 
detic Survey; Professors S. P. Langley and G. Brown 
Goode, Secretary and Assistant Secretary of the Smith- 
sonian Institution; Col. Marshall McDonald, Commis- 
sioner of Fisheries; Prof. Simon Newcomb, Superintendent 
Nautical Almanac; Dr. Frank Baker, Manager National 
Zoological Park; Prof. W. J. McGee, in charge United 
States Bureau of Ethnology (who has the unique distinc- 
tion of being a member of all seven societies); Prof. 
M. W. Harrington, Superintendent Weather Bureau; 
Prof. W. T. Harris, Commissioner of Education; Mr. 
A. R. Spofford, Librarian of Congress; Prof. John R. 
Proctor, President Civil Service Commission; General 
A. W. Greely, Chief Signal Officer; Surgeon-General 
George M. Sternberg; Dr. John 5. Billings, of the Army 
Medical Museum; Dr. C. W. Dabney, Assistant Secre- 
tary of Agriculture; Dr. B. E. Fernow, Chief of Division 
of Forestry, Department of Agriculture; Professors East- 
man, Hall and Harkness, of the United States Naval 
Observatory, and many other prominent officers of the 
Government. 
Congress is represented by Senators Manderson, Vilas, 
Perkins, Squire, and Wilson, and Representatives Baker, 
Belknap and Stevens. 
From the army and navy are many officers whose names 
are well known, among them General S. V. Benet, 
General J. C. Breckinridge, General TV. L. Casey, Com- 
modore O. C. Badger, Chief Engineer George W. Melville, 
Dr. J. Mills Browne, Dr. G. H. Beyer, Dr. N. L. Bates, 
Captain W. T. Sampson and Captain Rogers Birnie. 
Every branch of science is represented in these societies, 
and among many distinguished names a few may be found 
that are eminent in more than one sphere of research. 
Here is Prof. Lester F. Ward, who is not only a noted 
paleobotanist, but a profound student of sociology, and 
the author of ‘‘Dynamic Sociology,” ‘‘The Psychic 
Factors of Civilization’? and other works; also that of 
Mr. W. H. Holmes, who is known not only as a geologist 
and archeologist, but also as an artist; and that of Mr. 
Henry Gannett, chief topographer of the United States 
Geological Survey and author of numerous sociologic and 
economic papers, including a recent book entitled ‘‘ The 
Building of a Nation.” 
Among geologists are Professors G. K. Gilbert, S. F. 
Emmons, Arnold Hague, George F. Becker, J. S. Diller, 
