156 The Philippine Journal of Science oe 
hundred days and that animal 5983 outlived it by three hundred 
thirty days afford an indication that the treated animals were 
in some degree immunized. 
At autopsy animals 6078 and 5983 showed great emaciation 
with enlarged lymphatic glands and consolidated areas in the 
lungs. Sections of the lungs showed that these consolidated 
areas consisted mainly of fibrous tissue with very limited active 
processes. Tubercle bacilli were found in small numbers in 
the lungs of both and in the spleen of animal 6078 as well. 
Evidently a marked healing process was accompanying the 
progress of the tubercular lesions; but whether this healing was 
any more marked than in those nonimmunized controls which 
also exhibited a very chronic course of the disease is doubtful. 
On the whole, the evidence for immunization must rest largely 
on the longer survival of animals 6078 and 5983. 
In summary, while there is some evidence of the partial im- 
munization of these two animals, the average results of all 
animals give little encouragement for this method of treatment. 
It is possible that the method might be modified to serve a 
practical use in some immunization work—for example, that of 
cattle against bovine tuberculosis. The results obtained with 
the two animals long surviving indicate that the method is, at 
least, worth another trial in the same or a modified form. 
A noteworthy fact in these experiments in both control and 
. treated groups is the long life of a considerable number of ani- 
mals after infection with the test dose and the steady gain in 
weight of some animals even for two hundred or three hundred 
days after becoming distinctly tuberculous. During the slow 
progress of the infection, glands often formed abscesses, which 
broke down and later healed, the animal continuing in com- 
paratively good health. 
In the explanation of the long survival of animals in the above 
groups four factors must be considered: namely, the condition 
under which the animals were kept, the size of the dose, the 
virulence of the dose, and the method of inoculation. 
The conditions under which animals can be kept in the tropics 
differ widely, taken the whole season through, from those pre- 
vailing in most experiments on guinea pigs with tuberculosis 
conducted in northern countries. The temperature is fairly uni- 
form, making it possible to maintain a good ventilation at all 
times. The animals were kept in a house closed on the sides 
by wire netting only, and were confined in roomy cages, which 
were open to ventilation on the top and sides. Except in the 
