76 ACTIVITIES OF BACTERIA. 



According to Courmont and Doyon, the toxins are not ready-formed 

 poisons, but the body, during the time of incubation, furnishes the 

 final poison through the development of a ferment. The blood and 

 juice of muscles from animals suffering from tetanus act more promptly 

 than the toxin. Similar results were obtained by Blumenthal (Deut. 

 med. Wochenschr., 1898, No. 12, 185), G. G. Brunner contests this 

 upon experimental grounds (C. B. xxiv, 184). 



5. Sulphuretted Hydrogen. 



Sulphuretted hydrogen is a widely distributed bac- 

 terial product. It may be simply demonstrated as fol- 

 lows : By means of the cotton stopper a strip of moist 

 lead-acetate paper is fastened in the neck of the culture- 

 tube, which is then closed with a rubber cap (made from 

 dark rubber, free from sulphur). Frequent observations 

 are necessary, as the paper, which at first is brownish 

 and later blackish, and often only faintly discolored, 

 still later fades out. One must not arrive at negative 

 conclusions too soon. As the most beautiful method 

 for demonstrating sulphuretted hydrogen, Ernst em- 

 ployed gelatin colored Madeira-yellow with sodium ferri- 

 tartrate (ferrum tartar, oxydat. [Merk] 0.5, aq. 50.0, 

 and Na 2 C0 3 added until reaction is alkaline). This is 

 turned black by H 2 S. Literature: Petri and Maassen 

 (A. G. A. viii, 318 and 490) and Rubner, Stagnitta- 

 Balistreri and Niemann (A. H. xvi, 53). 



The sulphuretted hydrogen may be formed — 



1. From albuminous bodies. (As is well known, 

 boiling separates H 2 S from egg- albumin. ) This ability, 

 according to Petri and Maassen, appears especially in fluid 

 nutrient media rich in peptone (5% to 10% ) and free from 

 sugar, in connection with all the varieties studied, but in 

 most variable degrees. In bouillon free from peptone only 

 a few varieties (for example, Bact. vulgare) form H 2 S, 

 and in 1% peptone bouillon about 50% (Stagnitta-Balis- 

 treri). Among sixty varieties studied upon 2% peptone 

 bouillon we found twenty-eight — i. e., 47% — to be pro- 

 ducers of H 2 S. (See Table I, at end of book.) 



2. From sulphur powder. All bacteria in nutrient media to 

 which pure sulphur powder is added form really larger amounts of 

 H 2 S than without such an addition. Petri and Maassen point to this 

 production of H 2 S as a result of the action of nascent hydrogen, pro- 



