CHEMICAL PRODUCTS OF BACTERIA. 45 



This precipitate is soluble in alcohol, and is redeposited when the 

 alcohol is evaporated. On heating it is redissolved into oily drops of 

 a dark colour. With picric acid a granular precipitate is obtained, 

 •which under the microscope is seen to consist of minute crystals. 

 This precipitate, on standing, is converted into rounded crystalline 

 masses with numerous small crystals admixed. 



The ptomaine appears to be easily broken up by heating, 

 especially in the presence of mineral acids or of baryta. The actual 

 quantity obtained from a considerable amount of culture fluid was 

 very small, and as it was possible that when the bacilli were grown 

 in a medium richer in albumin, such as the animal body, more of 

 these products might be formed, the liquid obtained by extracting 

 large masses of tubercular growths from cattle was examined in a 

 similar manner. In this extract, after filtration through porce- 

 lain, an albumose, and minute quantities of a ptomaine were 

 obtained which in reactions was identical -with, that obtained from 

 the artificial cultivation of the bacillus, but present in even smaller 

 amount. The probable explanation of this is, that in the living 

 animal the ptomaine is constantly being removed ; or it may indicate 

 that it is only formed in minute quantity under those conditions. 



Having succeeded in obtaining the albumose and the ptomaine 

 in separate solutions, we next proceeded to ascertain the effects of 

 these substances upon healthy and tubercular guinea-pigs. 



The effect of the ptoinaine isolated from different series of 

 cultures was as follows. A rise of temperature occurred in tuber- 

 cular animals, and distinct enlargement of tubercular glands. There 

 was a slight indication of a depression of temperature or hypothermic 

 effect on healthy animals. The albumose, whether obtained from 

 pure cultivations of the bacillus or from tubercular tissue, pro- 

 duced a marked rise of temperature in tubercular guinea-pigs. On 

 the other hand, in a control experiment on a healthy guinea-pig 

 there was an equally well-marked fall of- temperature. The effect 

 upon the tubercular glands in the cases associated with marked rise 

 of temperature was to render them well-defined, indurated, and 

 painful, rather than any considerable increase in volume. 



Hunter made a chemical examination of Koch's crude extract, 

 and confirmed the presence of albumoses and alkaloidal substances. 

 The albumoses consisted chiefly of proto-albumose and deutero-albu- 

 mose with hetero- albumose, and occasionally a trace of dys- albumose. 

 Two alkaloidal substances were obtained in the form of platinum 

 compounds of their hydrochlorate salts. In addition there were 

 extractives, mucin, inorganic salts, glycerine, and colouring-matter. 



