REPORT OF TI[E SOCIETY 55 



used. Form III differs so little that it is a matter of doubt if it could be positi- 

 vely determined, but VIII gave differences that showed in the tables. The 

 differences observed with Leach's Form VIII are not shown, however, by the 

 group that comes under it when using his differential hosts. The recently 

 isolated culture 36 caused infection similar to that obtained with IV. This was 

 also observed on Well's Kidney Wax, which was not included because of four 

 plants that were susceptible when all the rest were resistant, excepting in the 

 case of Form IV, and culture 36, where all the plants were susceptible. 



A Group Separated by Cultural Characteristicts. 



Constant watch was kept from the first for any differences in the cultures 

 on the various media used to see if it were possible to identify the various cul- 

 tures or forms from one another and if any such differences did appear to see 

 if they confirmed the differences in infection results. Leach's Forms when first 

 transferred to potato dextrose agar gave quite noticeable variations but these 

 gradually disappeared in all cases but IV, and V, V being easily identified by a 

 whitish colony and very poor sporulation. There appears to be a constant 

 relationship between a whitish colony and poor sporulation. The distingishing 

 characters of IV remained constant on potato agar and were identical with cul- 

 tures 16 and 35. These cultures on slants of potato dextrose agar were slower 

 growing; had a tendency to lobing at the edge and formed a thick stroma-like 

 mat of mycelumthat developed very few spores and which as the colony aged 

 took on a very characteristic wrinkled appearance. The slow growth and 

 lobing of the margin was very evident in plate cultures but the stoma-like mat of 

 mycelium and wrinkled surface seldom showed. It is interesting to note that 

 the recently isolated culture 36 is showing a tendency to lobing at the margin 

 of the colony and is a very slow grower. No differences in spore sizes were 

 found. 



A comparison of Cultures on Different Sources of Carbon. 



The only work done on this that has been noted was by Leach (6). He 

 obtained such marked differences with mannitol that all cultures on hand at the 

 time were grown on a modified Czapeck's solution with it as the carbon source. 



The solution used is as follows: — 0.5 gm. magnesium sulphate, 1.0 gm. 

 monobasic potassium phosphate, 0.5 gm. potassium chloride, 0.01 gm. ferrous 

 sulphate, 2.0 gm. sodium nitrate and 30.0 gm. of cane sugar in one litre of dis- 

 tilled water. This solution was made up without the sugar, and the salts for 

 1000 cc. were mixed with 900 cc. of water. 45 cc. of this solution was placed in 

 each flask which were two sizes, one holding 200 cc. and a check that held 150 cc. 

 These were plugged and autoclaved at 17 lbs. pressure for twenty minutes. 

 After they had cooled, 5 cc. of an 8 per cent solution of the carbon source was 

 added, which made the concentration of the sugar in the culture 0.8 per cent. 

 The carbon source was first sterilized by using a Chamberland filter. The 

 flasks were inoculated by washing off all the spores that could be picked up in a 



