950 
ANIMAL DISEASES 
There has always been some non-specific back- 
ground fluorescence. We have isolated the virus 
from the hearts of mice up to ten days after ini- 
tial inoculation. The virus cannot be isolated 
after ten days. 
As far as the age of the monkeys, I don't have 
any idea because that's one of the problems of 
working with animals obtained from a biologi- 
cal supply house. We did maintain them in the 
vivarium for some six weeks to two months for 
observation, but we had no exact idea of their 
age. The mice were young, but they were not 
suckling mice. Daldorf established in order to 
produce the inff ction and some of the myopathy 
that occurs in the skeletal muscle, suckling mice 
are necessary, but we found that it really didn't 
make any difference whether these mice were 
newborn or two or three weeks old. We could 
still get myocarditis, although we couldn't get 
as much of the skeletal or the peripheral my- 
opathy. 
Dr. Pollard: There is another potential 
virus that has been associated with myocarditis 
and that is psittacosis. There is a question about 
whether or not it is a virus. Have you any addi- 
tional information on that as a possible etiologi- 
cal agent? 
Dr. DePasquale: Yes, someone mentioned 
that we might try it, but we had a lot of nerve 
doing this study, because none of us were virol- 
ogists, and we didn't really know how to handle 
these animals. We had the advice of a virologist, 
but none of us wanted to experiment with psit- 
tacosis at the time. But it's true that it is another 
agent which might be examined. I think my 
plea really is : Let's not just assume it's all rheu- 
matic fever and due to streptococcus. I think we 
should look for other things since we have this 
large number of patients without histories of 
rheumatic fever. Why should we accept it, just 
because our teachers told us (and their teachers 
told them) that it is due to rheumatic fever? 
Why shouldn't we look for other things ? 
Chairman Pierce: At this time, since we are 
running ahead of schedule, I'd like to include 
Dr. G. D. Hsiung. She is from Yale University. 
She is in laboratory medicine. She is Chief 
of the Virology Laboratory at the V.A. Hospital 
in New Haven, Connecticut. Her interests are 
pathogenesis and epidemiology of viral diseases 
in laboratory animals. Viral latency is probably 
her primary interest. Her presentation will be 
titled "Virus Infections of 'Normal' Healthy 
Animals." 
