46 BACTERIOLOGY. 



Swine Fever. Schweinitz applied Brieger's methods in the 

 investigation of the products of the swine fever, or hog cholera 

 bacillus. Broth- cultures were neutralised with dilute hydrochloric 

 acid, and evaporated in the water bath. The residue was treated 

 with 96 per cent, alcohol, and the filtered solution with mercuric 

 chloride. A heavy crystalline precipitate was separated by filtra- 

 tion, treated with water, and decomposed with sulphuretted hydrogen, 

 and cadaverin and methylamine were isolated. The filtrate from 

 the mercuric chloride precipitate was freed from excess of mercury 

 by sulphuretted hydrogen, and the mercury sulphide filtered off. 

 The residue, after concentration of the filtrate, was extracted with 

 absolute alcohol, and the solution showed the presence of an alka- 

 loidal salt. The double salt obtained with platinum chloride was 

 submitted, after crystallisation, to an analysis, and the results gave 

 the formula (C 14 H 34 N 2 PtCl 6 ). The hydro- chloride is soluble in abso- 

 lute alcohol as well as in water, and produces needle-like crystals. 



On treating the culture fluids with excess of absolute alcohol a 

 white flocculent precipitate was obtained partly soluble in water, and 

 re- precipitated by alcohol. It was obtained in the form of white 

 crystalline plates. A watery solution gives almost insoluble needle- 

 crystals on the addition of platinum chloride. These products were 

 respectively termed sucholo-toxin and sucholo-albumin. Small doses 

 of these substances produce in guinea-pigs a slight rise in tempera- 

 ture, and ulcaration at the seat of injection. Large doses produce 

 a fatal result in six to twenty-four hours. Schweinitz asserts that 

 he has produced immunity in guinea-pigs. An attempt to produce 

 immunity in swine by injection of the albumose gave unsatisfactory 

 results. 



Diphtheria. Roux and Yersin finding that filtered cultures of 

 the diphtheria bacillus produced paralysis, affecting chiefly the hind 

 legs, and a fatal result in rabbits and guinea-pigs, proceeded to 

 investigate the chemical products. They succeeded in obtaining a 

 white amorphous substance which was extremely active when 

 injected into guinea-pigs. It was precipitated by alcohol from an 

 aqueous solution, and it was calculated that '0004 gram would 

 destroy eight guinea-pigs of 400 grams, or two rabbits of 3 kilos, 

 each. They concluded that the poison was an enzyme or ferment, 

 as it not only acted in extremely small doses, but it was attenuated 

 by heat and destroyed by boiling. 



Brieger and Frankel confirmed these experiments, and asserted 

 that the poison was a tox-albumin ; but according to Martin their 

 chemical analysis and reactions were vitiated by the fact that they 



