9 
ate and drank most of it greedily. On May 17 and May 18 this was 
repeated. Xo other food was allowed ; so that in all the 33 rats ingested 
almost 3 liters of the virus in three days. 
Died. 
May 20, four days aftor feeding 4 
May 21, five days after feeding 4 
May 22, six days after feeding 1 
Total 9 
Nine of the 33 rats died. Death came rather suddenly. The others 
remained apparently healthy. An increased desire to drink probably 
indicated a feverish condition in some of them. Ordinarily rats die 
rather slowly from the effects of this virus. They have fever, show 
symptoms of distress, they are weak and prostrated, and refuse food for 
a day or two before death. 
It, therefore, seems plain that the ingestion of a small amount of the 
virus killed a few of the susceptible rats — 7 out of 70, and left the sur- 
vivors with a considerable protection, for, after feeding them for three 
days with overpowering doses, only 9 died out of 33. 
TEN EATS EEFED ON 10 C. C. OF BOUILLON CULTUEE. 
Ten of the rats that resisted experiment No. 1 were separated in a 
cage and subsequently fed with 10 c. c. of a young bouillon culture 
soaked on bread. This produced no effect. 
TEN EATS EEFED ON 2 AGAE SLANTS. 
Ten of the rats that resisted experiment No. 1 were subsequently fed 
with 2 agar slants, shaken in water and soaked on bread in accord- 
ance with instructions of Danyz. This produced no effect. 
TEN EATS GIVEN DEAD EATS TO EAT. 
Ten of the rats that resisted experiment No. 1 were placed in a 
separate cage and deprived of all food for four days, during which 
time rats sick and dead of the infection were placed in the same cage. 
They refused to touch the dead bodies. None of the 10 rats took the 
disease. 
It is evident from the foregoing experiments that small primary doses 
are uncertain in their effects. 
Another test was made, using large overpowering doses from the 
start. 
No. 2. TWENTY-SEVEN EATS FED ON VERY LAEGE QUANTITIES OF 
CULTUEE. 
Twenty-seven white and gray rats were deprived of food for twenty- 
four hours and then given (April 11) a liter of a young bouillon culture 
of the virus soaked on bread. In addition the}’ were given another 
2 
