CI1KMICAL PRODUCTS OF BACTERIA. 43 



properties, the alkaloid probably being in ;i nascent condition in the 

 .-iDmmose molecule. 



Tuberculosis. Koch prepared a glycerine extract of the 

 product of the tubercle bacillus in pure cultivations, and found 

 that the injection of small doses produced a remarkable reaction, 

 l>otli local and general, in tubercular cases, and especially lupus. 

 This extract, called tuberculin, came to be extensively used a.- a 

 therapeutic agent, but with disappointing results. Very shortly 

 after the first announcement of Koch's discovery, the author, in 

 conjunction with Herroun, investigated the chemical properties and 

 physiological effects of the products of the tubercle bacillus. 

 <'ultures in glycerine- broth were filtered through porcelain, and 

 a clear amber-coloured liquid was obtained, which gave important 

 and suggestive chemical reactions. As this filtrate contained the 

 products of the growth of the bacillus most probably in minute 

 quantities, it was evaporated at a low temperature over sulphuric 

 acid. The viscous residue was dissolved in distilled water and 

 tested on the healthy guinea-pig. The result was a marked fall of 

 temperature, staring coat, extreme irregularity of the heart's action, 

 muscular spasms, loss of control over the extremities, and death. 



A preliminary examination of glycerine -broth cultivations having 

 .shown the presence of iion-coagulable proteid bodies of the nature 

 of albumose and peptone, and a crystallisable precipitate of a 

 remarkable character resulting on the addition of iodine, the idea 

 naturally suggested itself that the tubercle bacillus might form 

 albumoses and an alkaloid or ptomaine similar to the substances 

 isolated by Martin from pure cultivations of the Bacillus anthracis. 



Koch pointed out that the effective substance in his extract 

 could be precipitated by absolute alcohol; the author and Herroun 

 determined to investigate the properties and physiological effects 

 of the separated products. They accordingly set to work to isolate 

 the ptomaine, of the existence of which they had some qualitative 

 indication, and at the same time to examine the properties of the 

 albuminous bodi->. 



In this endeavour the general method they found satisfactory was 

 as follows. The clear filtrate from the culture was evaporated at 

 40 C. to a very small bulk, and the residue thus obtained was 

 mixed with an excess of absolute alcohol, which precipitated the 

 albumoses and peptone. It was found that by adding the alcohol 

 by degrees a partial separation of the albumose from the peptone 

 could be effected, the latter being only precipitated when the alcohol 

 \\a- nearly absolute. The precipitated albumose was collected on 



