1888-89.] Messrs Macleod and Milles on Asiatic Cholera . 33 
be seen standing out prominently and ulcerated. This animal was 
the only one that had had loose stools. 
While 2 c.cm. of the cholera small gut contents was a deadly dose, 
the same quantity of cholera broth from the original cultivations was 
by no means so deadly. This might be due either to increased 
virulence of the organism after its passage through the animal, or to 
the greater number of bacilli present in the one than the other. The 
organisms were certainly more numerous in the bowel contents than 
in the broths injected. As plate cultivations were made from the 
former, and broth cultivations grown from these as nearly as possible 
under the same conditions, as to quantity inoculated, time and tem- 
perature in the incubator, the following experiments are worthy of 
record, though they were not made with the intention of comparing 
the relative virulence of the cultivations, and the quantities injected 
are not very suitable for comparison. Broth cultivations derived 
from the original cultivations brought from China, and therefore 
cultivated in gelatine for a year after being taken from the human 
stool in doses of 
5 c.cm. killed 5 out of 7 animals. 
2 „ 0 „ 4 „ 
1 „ 1 „ 3 ,, 
Similar cultivations of bacilli which had passed through three genera- 
tions of the guinea pig, reckoning the first generation the first animal 
inoculated with bowel contents, in doses of 
3 c.cm. killed 4 out of 4 animals. 
2-5 „ 1 „ 2 „ 
2 „ 0 „ 2 „ 
Similar cultivations of organisms passed through six generations in 
doses of 
2 c.cm. killed 3 out of 5 animals. 
Koch states that the organisms obtained during the last European 
outbreak of cholera, and kept under cultivation in his laboratory, 
have lost their virulence so far as guinea pigs are concerned, so that 
his former results are no longer attainable. 
In the guinea pig the larger the dose of cholera material given 
VOL. xvi. 30/1/89 c 
