229 
being higher on days when the humidity outside was high, and being 
raised each time the door had to be opened to admit of feeding, taking 
observations, etc. To the observer it proved very invigorating, com¬ 
parable probably to the air in the interior of Canada. The animals in 
the chamber, too, seemed more active and more interested in their 
surroundings than the controls which were kept in a greenhouse, 
artificially heated, but with a very varying temperature and with the 
humidity of the outside air. Curiously enough, the animals in the 
control house threw out actually longer coats than those in the cold 
chamber, and their appetites were markedly less. 
The animals subjected to the influence of the cold were guinea- 
pigs, rats and mice. The animals were placed in cages, well bedded 
and well fed, fat and proteid especially being provided in their diet. 
The diseases brought under the influence of the cold were chiefly 
various trypanosomiases, with, in addition, tubercle (bovine), cancer 
(in mice), tetanus, and spirochaetosis, and the results during over eight 
months’ observation are tabulated below. During the eight months 
there were occasional intermissions for a few days for repairs to 
machinery, etc., but they amounted to but quite a few days in all. 
In the table it will be noted that four animals died of pneumonia, 
an epidemic of which, unfortunately, occurred at one period and 
carried off several of the animals under observation. It was probably 
introduced with some wild rats placed at first near the controls, but 
affected both controls and cold chamber subjects equally. 
The influence of T. lewisi is, in any case, difficult to ascertain as 
rats recover spontaneously from this affection ; but it will be noted 
that the only animal which failed to show trypanosomes after inocula¬ 
tion with T. brucei was one in the cold chamber. The dose in all 
cases was, of course, the same, in terms of c.c. for the animal observed 
and its control, but the actual number of trypanosomes injected must 
vary within very wide limits, and this factor will influence the incuba¬ 
tion periods. Whereas it seems to be somewhat delayed in 
T. lewisi it varies but little in the other trypanosomes. There was 
a small prolongation of life in the Ngana and Caderas cases, but 
this did not hold good for T. lewisi and Dourine. 
Twelve mice were inoculated with cancer, and six put into the cold 
chamber; five lived 50, 51, 56, 70 and 90 days respectively, whereas 
their six controls, two lived 56 and 76 days respectively. 
