5 



agar by means of a sterilized platinum needle. In four days 

 the growth of the bacteria in the gelatine tubes had become 

 very profuse, and had clouded the entire mass of gelatine, 

 giving it a slight greenish hue. The growth of the bacteria 

 in the agar-agar tubes was different. Here the bacteria 

 spread out as a milky cloud around the entire length of the 

 path of the inoculating needle through* the agar, and also 

 over the surface of the agar as a more or less white, semi- 

 transparent and glossy growth. See figure 3, which repre- 

 sents the growth as it appears in agar-agar tubes. 



That this difference in the growth of the bacteria in the 

 ao-ar-asar and gelatine tubes was not due to a difference in 

 the kind of bacteria in each was proven by the numerous 

 cross inoculations that were made. Fresh agar-agar tubes 

 were inoculated with the liacteria from a gelatine tube cul- 

 ture, and fresh gelatine tubes inoculated with the bacteria 

 from an agar-agar tube culture, in all cases by means of a 

 sterilized platinum needle ; and in no case was there any 

 signs of a deviation in the method of groAvth or apperance 

 of the cultures peculiar to either the agar or to the gelatine 

 as above stated. 



In order to determine whether or not the bacteria of which 

 I had made pure cultures were the cause of the disease in 

 the cotton-bolls, I selected ten healthy cotton plants, and 

 with a sterilized needle, I made two punctures into four 

 healthy cotton-bolls on each of the plants, numbers 1, 3, 5, 



7, 9, and labeled each boll Then by means of the same 

 needle, sterilized and then infected with the bacteria from 

 the pure tube culture, I made two punctures into four 

 healthy cotton-bolls on each of the plants, numbers 2, 4, 6, 



8, 10, and labeled each boll. In twelve days all the cotton- 

 bolls inoculated with the bacteria from the tube cultures had 

 taken the disease in varying degrees, and in twenty days 

 they were entirely destroyed ; the entire contents of the 

 bolls having rotted, and the outer surface to a more or less 

 extent. On the contrary, the four bolls used as a control 

 experiment on each of the other five plants were perfectly 

 healthy and showed no signs of a disease, except one that 

 had been attacked by a fungus at the place where the needle 



