1922] 



YOUNG THE TOXIC PROPERTY OF SULPHUR 409 



sterile glass slide. A loop-full of spores was placed in this drop 

 and the spores evenly distributed throughout the drop. By 

 means of a small sterile glass rod a small portion of this drop was 

 transferred to a clean sterile cover glass and the latter inverted 

 over the glass cell. The cell was made air-tight by sealing with 

 petrolatum. In like manner cultures were made representing 

 each hydrogen-ion concentration both with and without sulphur. 

 The series of hanging-drop cultures were then kept at room tem- 

 perature. Examinations were made at the end of 16 and 24 hours. 



After examining some of the preliminary cultures it was found 

 that considerable irregularity in germination existed. Some types 

 of spores would remain on the surface of the drops and often 

 would not be in close proximity to the sulphur. Other types 

 of spores were found to be in the center of the drops with the 

 sulphur particles. Different-sized drops would often result in 

 irregular germination in the control cultures. With some or- 

 ganisms the number of spores in the drop influenced the rate of 

 germination. To eliminate such chance for error a definite spore 

 suspension was made and the drop on the cover glass was spread 

 over a much larger surface, giving it more the nature of a smear. 

 In this way a more even distribution of both the spores and the 

 sulphur particles was obtained. The results of the experiment 

 are recorded in table i and figs. 1-4. 



Sulphur in this form was found to be directly toxic to only 

 two of the organisms used. In the other forms the spores were 

 not only not inhibited from germinating but the germ tubes 

 grew normally when in direct contact with the sulphur particles. 

 It can only be concluded from these results that if the flowers of 

 sulphur has a general fungicidal value it must be due to some 

 change in the form of sulphur and that this change takes place 

 under different conditions than were obtained in closed-ring Van 

 Tieghem cells. Within the usual range for germination the hy- 

 drogen-ion concentration influenced the results but slightly. 



EXPERIMENT 2. FINELY GROUND FLOWERS OF SULPHUR 



Since the ordinary flowers of sulphur was toxic to two of the 

 organisms, it was concluded that there was a toxic property pres- 

 ent but in a very dilute form. If physical conditions influenced 

 the production of this property it was thought that possibly a 

 finely ground product might be more effective. To obtain sulphur 

 in this state an electricallv driven excentric mortar, as used for 



