1922] 



YOUNG — THE TOXIC PROPERTY OF SULPHUR 



427 



centrifuging, and peptizing were repeated 3 times, and the final 

 coagulum peptized in 100 cc. of distilled water. The reaction of 

 this peptized solution was Ph 4.2. Seventy-five cc. of this solution, 

 for convenience designated No. 1, were treated with 25 cc. of 

 normal ammonium hydroxide and let stand 24 hours, a white 

 precipitate being formed. This was neutralized and centrifuged. 

 The residue was suspended in 75 cc. of distilled water and desig- 

 nated solution 2. The filtrate, No. 3, was again treated with 

 25 cc. of normal ammonium hydroxide and left for 24 hours. A 

 slight precipitate was formed. This was neutralized, the precip- 

 itated sulphur centrifuged out and suspended in 10 cc. of water, 

 and this last designated solution 4; and the filtrate, No. 5. 

 Seventy-five cc. of the filtrate, No. 5, were again treated with 

 25 cc. of normal ammonia and left for 24 hours. No precipitate 

 formed. This was neutralized and called solution 6. 



Fifty cc. of solution 2 were treated with 25 cc. of normal 

 ammonium hydroxide and kept for 24 hours. It was then 

 neutralized and centrifuged. The residue was suspended in 

 50 cc. of distilled water and designated solution 7. Twenty-five 

 cc. of this solution were treated with 10 cc. of ammonia, allowing 

 the usual interval, then again neutralized, centrifuged, and sus- 

 pended in 25 cc. of water, constituting solution 8. A portion of 

 each of these solutions was tested for pentathionic acid, with the 

 result that Nos. 3, 5, 6, and 8 gave no positive test; Nos. 1, 2, 

 and 7 gave positive tests, but 2 and 7 only a slight indication. 



These solutions were then tested in respect to toxicity in closed- 

 ring cells, using the spores of Botrytis cinerea and Colletotrichum 

 Gossypii. The cultures were placed at 22° C. for 24 hours, and 

 the results, which are averages of duplicate cultures, are given in 

 table v. 



TABLE V 





PERCENTAGE OP GERMINATION 









Organism 



No. of solution 



1 



2 



3 



4 i 5 



6 



7 



8 



54 

 63 



Ck. 



Botrytis cinerea 

 Colletotrichum, 

 Gossypii 





 



10 



7 



50 

 61 



41 55 



54 1 65 



55 

 64 



26 

 18 



53 

 61 



of 



The amount of killing was directly proportional to the amount 



No. 8 contained as much sulph 



No. 1 but 



