306 



[Vol. 6 



ANNALS OF THE MISSOURI IIOTANICAL GARDEN 



cheese-cloth bags were filled with sterile clay soil which had 

 been inoculated with Protoderma from culture H8'. These 

 were placed in 6 sterile atmometer i ubes which were then filled 

 with sterile soil and enough sterile witer to moisten. The tubes 

 were corked and put in the ground at a depth of about 25 cm. 



The tube in the first experiment was examined after about 

 five months, on June 20, 191!», and Protoderma was found upon 

 the filter-paper and also to some extent in the soil. Abundant 

 growth was obtained in the part of the tube at the surface where 

 some light had entered because the flower-pot did not at all 

 times fit closely over the top. The rate of growth beneath the 

 surface was much less, but even at a depth of 1 m. the algal 

 cells were brilliantly green and healthy and had grown to some 

 extent into the soil. This is comparable to the growth occur- 

 ring under natural conditions, because in the soil samples taken 

 algal growth was so scant that it could not be detected with the 

 naked eye. In all cases the cells were either in plates or small 

 and large single cells, some of which resembled Protococcus. 



In the second experiment, the tubes were examined after dif- 

 ferent intervals of time. This method proved to be less 

 satisfactory than the above due to the difficulty of finding the 

 scattered algal cells among the soil particles. Thus, negative 

 results would not necessarily mean that the algal cells had dis- 

 integrated. 



Culture 



No. 



Time examined 



Interval 



1 



Feb. 12, 1919 



11 days 



2 



Feb. 18, 1919 



17 days 



3 



Feb. 24, 1919 



23 days 



4 



June 20, 1919 



140 days 



5 and 6 



June 27, 1919 



147 days 



Result 



Some brown and colorless cells 



No cells. 



Numerous green cells 



No cells. 



Numerous green cells (2 tubes 

 examined). 



The above results agree with those in the first experiment. 

 The fact that numerous Protoderma cells were found in the cul- 



