54 



LAWRENCE T. FAIRHALL AND PAUL M. BATES 



to kill both the vegetative form and the spore. Further ex- 

 periments were made in which both the time of exposure and 

 the distance from the source of light were varied. These are 

 set forth in the following table. Apparently Aspergillus niger 

 and B. coli in oil emulsion are somewhat more susceptible to 

 ultra violet radiation than B. subtilis. 



Emulsion II. Distance from lamp 5 cm. 



It will be noted in this connection that spore bearing molds 

 are quite as susceptible to ultra violet rays as B. subtilis, an 

 important point, since raw olive oil in particular was frequently 

 found to be contaminated with various molds. The effect of 

 ultra violet rays upon oil emulsions of Mucor and Penicillium 

 was also noted. The results obtained were similar in all re- 

 spects to those obtained with Aspergillus niger. With refer- 

 ence to the above, it is interesting to note that in the case of 

 aqueous suspensions of different species of Penicillium, Asper- 



