25 
The only explanation for this infection lies in Red Monkey 
No. 21. (See below.) Sooty Mangabey No. 65 was also asso- 
ciated with Red Monkey No. 21. 
Red Monkey No. 21 came in May, 1909, with a lot of 
monkeys purchased for experimentation and soon dis- 
covered to be badly infected (see 1910 report). It was injected 
May 24th, 1909, July 22nd, 1909, and November 11th, 1909, 
and while it gave good temperature charts after all tests, it 
was held because others in the same lot had died of tuber- 
culosis, or were suspected of having it. (Anubis No. 38, 
Malbrouck Monkey No. 2, see 1910 Report.) However, after 
death of all suspicious monkeys of this lot and having been 
in quarantine seven months, he was passed January 3d, 1910. 
He was put into the cage which afterwards received Green 
Monkey No. 80, following the death of which he was returned 
to the Laboratory, and tested April 25th, 1910, and June 
24th, 1910, giving good reactions on both occasions. Being 
returned to the Monkey House he was put into the cage 
containing Sooty Mangabey No. 65 and other monkeys as 
shown on the chart under the last-named animal. 
One cannot help feeling that this monkey has carried the 
infection, possibly ever since May, 1909, without himself 
giving evidence of the disease. 
A healthy monkey may carry on his hair tubercular material 
if his cagemates before he is received at the Gardens were 
tuberculous. And though he may pass the tuberculin test 
on admission he may later contract tuberculosis from the 
material carried on his own body. Therefore, all monkeys 
as soon as received are now washed with soap and water and 
rinsed in carbolic acid solution. 
We do not feel that this experience militates in any way 
against the value of the tuberculin test in monkeys. The only 
entirely inexplicable case concerns the Rhesus Macaque No. 
115, the others having at least a balance of circumstantial 
evidence in favor of the outlined course of infection. 
