102 



STUDY AND IDENTIFICATION OF BACTERIA 



The best stains are carbol thionin and formol fuchsin. In sections stained with 

 carbol thionin the bacilli are apt to be decolorized by the subsequent passage of 

 the section through alcohol and xylol. This may be avoided by blotting carefully 

 after the thionin, then clearing with xylol or some oil and mounting. Nicolle's 

 tannin method is a good one. 



Mallein is prepared by sterilizing cultures that have grown in glycerine bouillon 

 for about a month by means of heat (iooC.). The dead culture is then filtered 

 through a Berkefeld filter and the filtrate constitutes mallein. It is chiefly used as 

 a means of diagnosing the disease in horses. The reaction consists in rise of tempera- 

 ture and local oedema. The dose is about i c.c. 



Agglutination and complement-fixation tests are also used for diagnosing glanders. 



Bacillus Diphtheria (Klebs discovered, 1883 ; Loffler cultivated, 1884). 

 The diphtheria bacillus is found not only in the false membrane which 







FIG. 27. Bacillus of diphtheria. (Xiooo.) (Mac Ned.) 



is so characteristic of the disease, but may be found in abundance in 

 the more or less abundant secretions of nose and pharynx. In studying 

 the epidemiology of diphtheria, especial attention must be given to the 

 examination of nasal discharges. 



With diphtheria carriers it is important to remember that the crypts of the tonsils 

 may harbor the bacilli and thus protect them from the ordinary application of 

 antiseptic agents. Goldberger found that the combination of throat and nose cul- 

 tures gave much higher findings with carriers than either separately. The nose 

 cultures gave more positives than the throat ones. These workers only obtained 

 about i % of positives in 4093 cases in Detroit, these being lower than figures from 



