276 



the work which has been performed is simply a continuation of some in- 

 vestigations begun during the season of 1898, and reported in the Acad- 

 emy Proceedings for that year, pp. 64-70. At that time work was under- 

 taken with both wheat and oats smut, but on account of the fact that the 

 wheat smut spores did not remain viable under laboratory conditions 

 this portion of the work had to be abandoned. P'urther opportunity for 

 study of the wheat smut did not present itself till last summer. A con- 

 siderable quantity of smutted heads was collected from last year's wheat 

 crop just after the grain headed out, and before the spores were blown or 

 washed off the rachis. This material was kept in the laboratory until 

 needed for use. Spores mounted in hanging drop culttires over moist cells 

 showed good germination in distilled or tap water at the time the material 

 was collected, but in the course of two or three weeks failed to germinate. 

 As these results corresponded with those of 1898. it was decided to try 

 germinating them in some nutrient solution. Accordingly a Pasteur sugar 

 solution was substituted for the water, with the result that a vigorous 

 germination was obtained. 



In order to insure a uniform lot of spores for the culture experiments, 

 a sufficient quantity of them were jaiTed from the smutted heads, and 

 after removal of the detritus by screening, they were thoroughly mixed 

 and collected in a receptacle from which fresh supplies were drawn as 

 desired. 



Treatment of the spores.— The spores were treated in muslin sacks, one 

 corner of which was weighted with a small quantity of shot In order to 

 carry the sacks down into the solution and maintain them in proper posi- 

 tion while being treated. 



In treating the spores, especially in the formalin solutions it was 

 found absolutely essential that only a minute quantity of spores be taken, 

 otherwise they were apt to collect in masses, and in this way the solu- 

 tion did not readily permeate the whole mass. Whenever this occurred, 

 in the shorter periods of treatment, spores taken fi'om the interior of these 

 masses would invariably show germination. 



Formalin treatment.— The strength of formalin solutions used were .18, 

 .25 and .5 per cent. The periods of treatment to which the spores were 

 subjected in these solutions were one-quarter, one-half. one. and two 

 hours, the four lots of spores being treated at the same time, each being 

 successively removed without in any way disturbing the remaining ones. 

 The treated spores were mounted as soon as possible after removal from 



