231 



" ■■• • \ v^ .s^P „>«- . 



inoculations on 21. III. 22. this was the only medium used 

 apart from a few cases where plate cultures were made on 

 Fildf.s medium. Subsequent cultivation took place on Fildes 

 plates. 



While it is a general rule for the more fastidious bac- 

 teria (Meningococcus, Gonococcus, etc.) that the primary cul- 

 ture is more exacting in its demands upon the nutritive medium 

 than the subsequent subcultures, the converse is the case for 

 Pfeiffer's bacillus. This depends upon the simultaneous ino- 

 culation of growth-promoting bacteria which (in sputum, m'ucus 

 from the throat, etc.) are practically always present in suf- 

 ficient quantity to exert an effect. On the other hand the demands 

 of Pfeiffer's bacillus for a medium of a definite constitution 

 decrease after a long period of cultivation, as previously men- 

 tioned, to a less extent than is the case with the majority of 

 other bacteria. 



In the investigations on 21. III. 22. besides the medium men- 

 tioned, others were used for some of the inoculations, prepared 

 in the same way except that the agar was made partly ,with 

 Hottinger's broth (8 litres of broth from 1 kilogram of meat), 

 and partly with Cole & Onslow's broth (40 litres of broth from 

 1 kilogram of casein. The digestion of the casein however, was 

 carried out with Pancreatin „Rhenania", not with extract of pig's 

 pancreas). 



The first-named medium gave a rather slighter growth of 

 Pfeiffer's bacillus than the ordinary peptone broth agar, while the 

 last proved to be absolutely useless. 



For subeultivation of Pfeiffer's bacillus I also (earlier) tried 

 Hottinger agar (as Fildes plates), chiefly in strong concentra- 

 tions. With the most favourable concentration (4 litres of broth 

 from 1 kilogram of meat) the growth of Pfeiffer's bacillus was at 

 times just as good as on ordinary Fildes plates and at times, 

 not so good. 



Huntoon's agar is stated to possess specially good .,vitamiue" 

 qualities (1) because the agar is boiled with the meat; (2) because 

 it is not filtered through wool, paper etc. The hope of thus ob- 

 taining a particularly good medium for the most atypical Pfeiffer's 

 bacilli which usually only grew slightly and were easily lost, was 

 not realised however. I did not succeed in making a better „basic 

 medium" than the classical peptone broth agar. 



The liquid medium principally used was broth con- 

 taining about l°/ 00 dissolved horse blood corpuscles. If broth 



