358 BACTERIA PATHOGENIC TO MAN - 



and others, its activity is due to the presence of certain substances 

 called opsonins (Wright), or bacteriotropic substances (Neufeld), which 

 act on the bacteria in such a way as to prepare them for ingestion by 

 the phagocytes. 



Agglutination Reactions. It has been shown that the specific serum 

 obtained by the above method may contain a considerable quantity of 

 agglutinating substances for the strain of pneumococcus inoculated and 

 for certain other strains, but not for all. In the case of the pneumo- 

 coccus mucosus (streptococcus mucosu-s Schottmiiller) we have found 

 that all of the strains tested by us were agglutinated in high dilutions 

 in the serum obtained after the inoculation of one strain. 



Therapeutic Experiments. The number of cases reported in which 

 the blood-serum of animals artificially immunized against pneumonic 

 infection has been used for the treatment of the disease in human 

 beings, although numerous has not led to the formation of a definite 

 opinion as to the final value of this as a therapeutic agent. In the cases 

 we have observed there has been in some a slight immediate lowering 

 of the temperature; in others no apparent change. As a rule, the cases 

 did rather better than was expected, but certainly no striking curative 

 effects were apparent. The cases did not develop pneumococcus blood 

 infection, and it seems probable that the serum may be able to prevent 

 a general infection from taking place from the diseased lung, even 

 though it may fail to influence the local process. It has also been shown 

 that these injections of antipneumococcic serum are practically harmless. 

 In pneumococcus septicaemia no marked results have been seen. The 

 majority who received the injections, as well as those not receiving 

 them, died. 



The Pneumobacillus of Friedlander. 



This bacillus discovered by Friedlander (1883) is now known to occur 

 frequently as a mixed infection in cases of phthisis, fibrinous pneumonia, 

 and in rare instances as the only exciting factor in pneumonia. It is 

 also not infrequently found in the mucous membranes of the mouth 

 and air passages of healthy individuals. 



Morphology. Short bacilli with rounded ends, often resembling micro- 

 cocci, especially in recent cultures; commonly united in pairs or in 

 chains of four, and, under certain circumstances, surrounded by a trans- 

 parent capsule. This capsule is not seen in preparations made from 

 artificial culture media, but is visible in well-stained preparations from 

 the blood of an inoculated animal. 



Friedlander's bacillus stains readily with the aniline colors, but is not 

 stained by Gram's method. 



Biology. An aerobic, non-motile, non-liquefying bacillus; also facul- 

 tative anaerobic; does not form spores. In gelatin stick cultures it 

 presents the "nail-shaped" growth first described by Friedlander, which 

 is not, however, peculiar to this bacillus. Gas bubbles occasionally 

 develop in gelatin, and in old cultures the gelatin acquires a distinct 



