158 ATLAS OF BACTERIOLOGY. 



In an entire series of important infectious dis- 

 eases, on the other hand, we are almost entirely un- 

 able to explain them on a chemical basis. These 

 include anthrax, rabbit septicaemia, hog erysipelas. 

 Filtrates through porcelain of the most virulent 

 cultures are inert ; the cultures, which are cautiously 

 killed by briefly warming them or by a short expo- 

 sure to chloroform, produce only the general protein 

 action (fever) when injected. Yet it is probable that 

 even these diseases are toxaemias due to bacterial 

 metabolic products. 



It is to be regarded as an important finding that 

 Petri and Maassen (A. G. A., VIII., 318) were able 

 to demonstrate the sulphmethsemoglobin stripe in 

 the fresh blood and oedema fluid of erysipelatous hogs 

 a sign that poisoning with sulphuretted hydrogen 

 at least plays a part in the death of the animals. 

 Similar evidence has also been obtained in malignant 

 oedema. 



Hoff a regards rabbit septicaemia as methylguanidin 

 poisoning (Langenbeck's Arch., 1889, p. 273). Em- 

 merich and Tsuboi (Munch, med. Wschr., 1893, No. 

 25) explain cholera as a nitrite poisoning, but this 

 has been vigorously opposed. 



These explanations are very interesting, but they 

 do not seem to suffice, inasmuch as, apart from the 

 toxic processes just mentioned, there are at least 

 other specific processes in the blood and tissues of 

 the animal. This is proven, among other things, by 

 the development of specific protective substances 

 ("anti -bodies"). 



In order that a pathogenic action may be observed 

 the micro-organism must be in a condition of vigorous 



