66 Journal of Agricultural Research voi.xii.No.a 



METHODS OF EXPERIMENTATION 



In the earlier sporophore study the tubes containing the cultures 

 were kept both horizontally and vertically. If the species under investi- 

 gation produced sporophores at all, they were able to produce them in 

 either position. However, the practice was soon abandoned of placing 

 the tubes in a vertical position, since it was found very difficult to obtain 

 uniformity in the proper Ughting of the cultures and to get spore prints 

 from the sporophores produced in such a position. 



The general method followed in the sporophore studies was to take a 

 series of tubes on different agars and place them in the same general posi- 

 tion that was described in the study of the cultural characters. It was 

 found very important early in the study that the slant side of the tube 

 should be kept uppermost and that the relative position of the tube 

 in reference to gravity and sunlight should be the same throughout the 

 experiment. The tubes were so placed that the cotton plugs were 

 away from the simUght and the bottom of the tubes faced the light. 

 As soon as there was any indication of a hymenium forming, the tubes 

 were placed with the slanting surface downward. After this was done, 

 the sporophores usually continued to develop normally, and in due season 

 spores would be formed and discharged against the side of the tube op- 

 posite the hymenium. 



The first sets of fungi which were kept in darkness were placed in 

 pasteboard boxes in a horizontal position and these boxes inclosed in 

 other pasteboard boxes. It was found, however, that some diffused 

 light reached the tubes in spite of the double-box arrangement. Inside 

 one of these boxes the recording tube of the soil thermograph was 

 placed, while the registering portion of the instrument was kept on a 

 shelf outside the boxes. These boxes were kept on the shelf beside the 

 other bcJxes containing the tubes which were exposed to the direct rays 

 of the sun. This was done in order to obtain as near as possible the 

 same environment for the tubes kept in the sunlight and those kept in 

 the darkness, except for the single factor of Ught. 



In a later series of experiments, the ones which are recorded in detail 

 in this paper, the cultures were kept in pasteboard boxes in a horizontal 

 position and these boxes were placed in a photographic dark room from 

 which all light was excluded by means of sheets of cardboard being placed 

 over the ruby lights. By this arrangement absolute darkness was ob- 

 tained for the cultures. The soil thermograph was arranged in the same 

 manner in the dark room as when on the outside. Table XV shows the 

 highest maximum and minimum, the lowest maximum and minimum, 

 the highest and the lowest mean, and the average of the daily maximum, 

 minimum, and mean temperatures for each month as recorded by the 

 two thermographs. 



