222 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO. 10 



finding it devoid of all flavor, they concluded that their suspicion had 

 been unfounded. The low percentage figure of the organic matter 

 present may explain the fact that it is imperceptible to the taste. 

 However, if the ice is allowed to melt, the presence of the organic 

 substance readily manifests itself to the eye through the pronounced 

 turbidity of the solution. The organic substance is, therefore, 

 probably of colloidal character. The question as to whether or not 

 its presence in these ices bears any relation to the peculiar shapes of 

 these structures is, of course, unanswerable at the present time. Our 

 knowledge of the properties of colloidal organic substances is still too 

 incomplete. 



An attempt was made to obtain an idea as to the chemical nature 

 of the organic substance present in these ices. Upon concentrating 

 the opaque solution on the steam-bath, a yellowish brown fluid was 

 obtained which had a pleasant odor, similar to freshly baked bread. 

 With ferric chloride solution, a yellow coloration was produced. Per- 

 manganate solution, made slightly alkaline, was readily reduced with 

 the formation of an aldehydic odor (not of benzaldehyde, however) . 

 Bromine solution was decolorized. These tests would indicate an 

 aromatic unsaturated compound. The latter was tentatively assumed 

 to belong to the styrolene group, of which cinnamic and cumaric acids 

 are members. This assumption was strengthened by the following 

 biological observation. A solution of melted ice from bare soil, after 

 thorough filtration, was kept in a cold storage compartment at a con- 

 stant temperature of about 1° C. After two weeks, on examining 

 the liquid microscopically, I found it to contain a bacterium in what 

 appeared to be practically a pure culture. The liquid was turned 

 over to Dr. Edwin Le Fevre of the Microbiological Laboratory, who 

 made a careful study of the organism. In this connection. Dr. Wil- 

 liam J. Robbins has isolated from soil a bacterium which is capable of 

 utilizing cumarin as a source of carbon.^ Dr. Robbins was kind 

 enough to send us a culture of the bacterium, and the two organisms 

 were subjected to a comparative study by Dr. Le Fevre, who reported 

 that the classification of both organisms should be the same. 



From these observations, it would appear that the present physical 

 explanations for the above-mentioned frost phenomena are inadequate 

 and that they cannot be fully explained until the nature and the 

 physical properties of the organic substance present in these ice 

 structures have been elucidated. 



3 W. J. Robbins, Science, N. S. 44: 894. 1916. 



