44 BACTERIOLOGY. 



a, filter and reilissoheil in distilled water. In anothei' experiment 

 the albumose uudei'weut a second precipitation, and after washing 

 was again dissoh-ed. 



The a,lcoholic filtrate from the precipitated albuminous bodies was 

 then concentrated at a \x'ry gentle heat until a \isi'ous residue was 

 left containing the glycerine originally present in the cultivating 

 medium and the extractives and products of the bacillus soluble 

 in alcohol. With this residue definite reactions of an alkaloidal 

 s\ibsta,uce or ptomaine were obtained. 



Careful ex[)eriiuents, however, led to the belief that the whole 

 of the ptomaine was not separated from the M,lbuminous precipitate 

 liy simple addition of alcohol, and the above method was therefore 

 slightl}' modified. 



The ptomaine is soluble in water and alcohol, and sparingly 

 soluble in amyl-alcohol, but insoluble in benzine, ether, or chloro- 

 foi'm, which liquids therefore fail to extract it from aqueous 

 solutions. In its aqueous solutions it is distinctly but not strongly 

 alkaline to test-paper. Phospho-tiingstic ai^id gives with it a \\hite 

 flocculent precipitate. Phospbo-molybdic acid gives m, pale yellow 

 precipitate, solul)le in annnonia to a blvie solution which becomes 

 colourless on boiling. In tins respect it resembles the vegetable alka- 

 loids, aconitin a,nd atropin. It must be remend)ere(l, however, tluit 

 albuminous bodies are precipitated by both this and the preceding 

 reagents, and in the case of the former a reduction of the phospho- 

 molybdate giving tlie blue solution with ammonia is obtained. 



The reducing power of the ptomaine is shown by the con\ersion 

 after a short time of fei'ri-cyauide of potassium to ferro-cyanide, 

 giving the Prussian blue test with ferric chloride, to which much 

 undue importance was attached by Brouardel and Boutmy. Thc^ 

 solution of albumose and solution of peptone are both capable of 

 giving this reaction as well a,s manj' vegeta-blo alkaloids. A solution 

 of the ptomaine is not precipitated by ferro-cyanide of potassium or 

 potfissic bichromate. 



In Strong solutions it yields precipitates with platinic chloride 

 (yellow), gold chloride (pale yellow), and mercuric chloride (white). 

 That yielded by t)ie first of these reagents is grauulai' in cliaracter, 

 and (juite insoluble in alcohol, though apparently soluble in water. 

 The precipitation by gold chloride excludes amides and ammonium 

 salts. 



With iodine in hydriodic acid or potassic iodide a precipitate is 

 (jbtained which is occasionally ciystalline, more often gi'anular or 

 amorphous. 



