46 CASPER O. MILLER. 



Chond. diff. He fails to raentiou how long the interval was 

 between the planting of the spores and the formation of the 

 sporangia. He also planted the spores of Arcyria punicea, 

 Pers., Trichia nutans, Libert, and Stemonitis dictyo- 

 spora, Rostaf.j on sterilised decayed beech-wood in flat 

 crystallising dishes, containing water to the depth of '5 cm. 

 He did not see the plasraodia of the first two in the water; 

 they developed in the interior of the wood, and only appeared 

 on the surface when the sporangia were formed. The Ste- 

 monitis developed plasmodia in the water^ and fourteen days 

 after their first appearance the sporangia were formed. He 

 fails to state how long it took for the plasmodia to develop 

 after the spores were planted. 



Although Celakovski sterilised his nutrient media and the 

 vessels, no observations were made as to the presence or 

 absence of contamination. It is very difficult to prevent the 

 contamination of cultures in a large flat dish, when the lid is 

 removed or lifted for the purpose of examining the culture. 



My cultures were first made as controls for another series 

 of experiments, but the results seem of sufficient interest to 

 publish as a separate paper. 



The Methods employed. 



In the summer of 1890, while making some experiments at 

 the pathological laboratory of the Johns Hopkins Hospital, to 

 determine what Protozoa one finds in the air, a number of 

 flasks, containing sterilised water with 2 per cent, of milk 

 added, were left uncorked for a number of days. Of the 

 flasks one showed zoospores of Mycetozoa, which were trans- 

 planted a number of times. The zoospores and plasmodia 

 developed, but no sporangia appeared. 



The first systematic attempt of the writer to cultivate Myce- 

 tozoa was made at the Zoological laboratory at Heidelberg 

 in 1893. 



A culture was prepared in the laboratory for the study of 

 Infusoria, by simply placing unsterilised hay in a glass jar with 



