1922] 



YOUNG — THE TOXIC PROPERTY OF SULPHUR 



415 



boiling together 80 lbs. of sulphur, 36 lbs. of lime, and 50 gal- 

 lons of water, the first reaction is the more probable one. When 

 prepared in this way the mixture has about the following com- 

 position: sulphur as sulphides (largely pentasulphides), 80.7 

 per cent, as thiosulphates, 19 per cent, as sulphites and sulphates, 

 0.03 per cent. 



Lime sulphur mixtures are extremely alkaline and their initial 

 efficiency as a fungicide may be due partly to this causticity, that 

 is, to the free hydroxyl ions. An experiment was performed to 

 determine how long this causticity remained when the spray 



Buffered Flixture 



Fig. 



cultures: 

 sulphur • 

 sulphur ■ 



9 Germination of spores of Colletotrichum GossypU in hanging-drop 



of hydrophobic colloidal 



toxic action of flowers of sulphur 



of hydrophilic colloidal sulphur 



» 



check, without 



was applied, and to ascertain, if possible, whether this factor was 

 the principal one in giving lime sulphur its prolonged effective- 

 ness as a fungicide. For this purpose lime sulphur was prepared 

 according to the formula given by Van Slyke, and 1 part of the 

 lime sulphur diluted with 6 parts of water. This is a little 

 stronger than the concentration used as a dormant spray. 

 Twelve large moist chambers were sprayed with this mixture and 

 kept under the following conditions: Four were exposed to dry 

 air; a second set of 4 was placed under slightly humid condi- 

 tions, and a third set of 4 in a saturated condition. After 2 hours 



