200 SPECIAL BACTERIOLOGY 



from fluid cultures rich in fat. The development is allowed to go on 

 for about a month, the broth being shaken now and then to ensure 

 a series of successive crops. The organisms are then killed by 

 exposure to 70 C. for an hour. This is used as a vaccine, and 

 before use it is shaken and 3 c.c. injected. The efficacy of the serum 

 with plague patients has yet to be determined. 



BRONCHO-PNEUMONIA BOVIS. 



(Infectious Broncho-pneumonia Nocard ; Corn Stalk Disease 

 Billings ; Bacillus Zeae Burril.) 



The disease occurs among American cattle at certain seasons of 

 the year, and, according to Billings, is caused by an ovoid belted 

 organism which infects cattle eating the leaves and tender top shoots 

 of the corn stalks, and from this circumstance he named it ' The 

 Corn Stalk Disease/ Nocard, on the other hand, found some cattle 

 amongst a lot landed from America affected with a specific lung 

 disease, which at the first glance presented the appearance of a recent 

 lesion of contagious pleuro-pneumonia ; but careful microscopical 

 examination revealed the presence of ovoid belted organisms that 

 could be differentiated in the lymph spaces resembling a state of 

 pure culture. M. Nocard says : 4 This single character alone sufficed 

 to affirm that the lesion was not of a pleuro-pneumonic kind.' The 

 author also discovered the presence of morphologically identical 

 organisms in sections of a piece of the lung of an American ox 

 received from Professor Williams (see Photomicrograph, Fig. 79). 

 A portion of this lung, as well as stained sections, were sent to M. 

 Nocard, who replied : ' It is a bacteridian broncho-pneumonia, which 

 in all probability is of the same nature as that I have already 

 described." In the absence of cultures, M. Nocard, though stating his 

 belief in the identity of the organisms, could not be absolutely 

 definite. 



Microscopical Appearances. Short oval bacteria 1 //, long, and 

 about '5 p in width. 



Motility. Strongly motile. 



Staining Reactions. Stains readily with alkaline methylene blue, 

 when the clear spaces in the centre of the organism are well differ- 

 entiated. By the Gram method the reaction is negative. Sections are 

 best stained with methylene blue, according to Weigert's original 

 method (see Technique, 37) ; also with fuchsin. 



Biological Characters. According to Billings the growth is more 

 characteristic at ordinary room temperature than in the incubator. 



