culture media, but more -rapidly at 25*^ to 35® C In 

 gelatine tube cultures, the growth in three days gives a 

 milk}' appearance, which spreads from the line of puncture 

 of the inoculating needle, until in five daj^s the entire gela- 

 tine becomes milky and assumes a slight greenish color. In 

 agar-agar the growth on the surface appears as a smooth, 

 semi-transparent, milky layer ; while the development along 

 the line of the puncture of the inoculating needle through 

 the agar takes place as a cloudy, more or less even growth, 

 gradually becoming thinner at the periphery. 



Pathogenic. — Inoculated into healthy cotton-bolls, a dis- 

 ease resulting in a rotting or decaying of the seed and lint 

 is produced in from one to two weeks, which soon involves 

 the carpels, and thus destroj^es the entire cotton-boll. 



This new rot disease of the cotton-boll is readily distin- 

 guished from the only disease likely to be confounded with 

 it, namely anthracnose, by the fact that the anthracnose first 

 makes its appearance as small, reddish brown spots on the 

 surface of the boll, which spots enlarge and become dark, 

 gray or pink according to circumstances. Finally, when 

 the spots have attained a considerable size, they will be 

 found to consist of a pink centre surrounded by a dark 

 band, and this in turn surrounded by a dull, reddish brown 

 band. The anthracnose is caused by a fungus, colletotrichum 

 Gossypii, Southworth* which originates on, and is usually 

 confined to, the carpels of the boll, and only occasionally 

 infects the lint. 



The new rot disease of the cotton-boll, on the contrary, 

 originates within the boll, and does not make itself visible, 

 as a rule, until the entire or nearly entire contents of the 

 boll has become involved and decayed, when the carj^els 

 may become affected and show signs of decay in places. 

 The cotton-boll rot is caused by a bacterium. Bacillus 

 gossypina, Stedman, and first appears as a small black or 

 dark brown area on some of the young and developing seed 

 and lint inside the boll near the petiole. This area gradu- 

 ally enlarges and causes the affected parts of the seed and 



* See Bull. No. 41, On "Some Diseases of Cotton," by G. F. Atkinson 

 p. 40. 



