X, B, 2 Barber: Experiments on Immunization 157 
few cases of females having young, only one animal was put 
in a cage. They were given a uniform daily diet of cooked rice 
and grass with no water except that contained in the rice. 
Among the guinea pigs of this laboratory there have been few 
of the epidemics not uncommon in many laboratories. Doubtless 
these favorable conditions contributed to the resistance to tuber- 
culosis of the animals used in these experiments. 
Lack of virulence for guinea pigs in bacilli from the mixed 
sputum of three human pulmonary cases would hardly be ex- 
pected, and the short treatment with 25 per cent antiformin was 
scarcely sufficient to affect the virulence. The size of the dose 
could not be closely estimated since the proportion of dead bacilli 
in the sputum could not be known. Nearly all animals, however, 
showed tubercles within a short time after inoculation. In the 
subcutaneous inoculation a slower progress of the disease would 
‘ be expected than by the intraperitoneal. < 
In any case, either the smallness of the dose or a possible 
lack of virulence must have affected the result, since animals 
in other groups (see Tables V and VI), kept under the same 
conditions and inoculated subcutaneously with bacilli from a pure 
culture of another origin, survived a much shorter time. 
OBSERVATION ON ANIMALS INOCULATED WITH TUBERCULOSIS 
FROM LEPERS 
SERIES A 
On October 9, 1911, a monkey was inoculated subcutaneously 
‘with spleen pulp taken at post mortem from a case of leprosy 
which showed very numerous leprosy bacilli in the spleen. This 
monkey (No. 5804) died December 6, 1911, with lesions of 
tuberculosis. Spleen emulsion from monkey 5804 was inoculated 
into monkey 5975, which died twenty-nine days later (primarily 
of tuberculosis). From the inguinal glands of this monkey a 
pure culture was made. This culture was inoculated May 31, 
1912, into a series of 20 guinea pigs. An amulsion in salt 
solution was made of a 106-day culture on glycerin agar plus a 
few drops of human serum. A portion of this emulsion was 
further diluted with salt solution, and a portion was mixed in a 
stiff agar containing 5 per cent glycerin. Dilutions were made 
so that the dose employed, 2 cubic centimeters, contained in both 
salt solution and agar approximately the same quantity, about 
0.04 of the original culture. By counting, the dose was found 
roughly to approximate 1,000,000 bacilli. All inoculations were 
