﻿BOTANICAL GAZETTE 



No previous investigations have been made of the effects upon 

 protoplasm of light in this region of the spectrum. 1 One reason for 

 this is that the employment of Schumann rays presents many diffi- 

 culties. A special technique is required, and sources of these rays 

 suitable for biological investigations have been lacking. The inves- 

 tigations on Schumann rays described in this paper were made 

 possible by the kindness of Professor Theodore Lyman, who 

 placed at the disposal of the writer the necessary apparatus and 

 pointed out the methods by which the difficulties of technique 

 might be surmounted. 



The effects of ultra-violet light upon a variety of organisms have 

 been studied and an attempt has been made to follow as carefully 

 as possible the changes produced in the protoplasm. The changes 

 in structure have been followed by observing the organisms under 

 the microscope during the action of the ultra-violet light. The 

 comparative efficiency of waves of various lengths in producing 

 these changes has been studied by a variety of methods. 



As previously stated, it has been found that Schumann light is 

 much more injurious to protoplasm than any light heretofore 

 reported. An exposure of only a few seconds to the light from a 

 comparatively feeble source is sufficient, not only to bring about 

 death, but also to cause a complete disorganization of the proto- 

 plasm. It has further been found that the destructive action is 

 not lessened when the organism is exposed while it is thoroughly 

 desiccated and in a high vacuum. As will be pointed out later, 

 this fact is significant, for it indicates the direction in which we 

 must look for an explanation of the changes produced by these and 

 other electromagnetic waves. 



While no record of previous investigations of the biological 

 effects of Schumann rays has been found, it seems advisable to give 

 a brief review of certain investigations relating to the biological 

 effects of light of longer wave lengths. 



Taking sun baths for hygienic purposes is a very ancient 

 and widespread practice. The heliosis and the insolatio were 



1 Biixon-Daguerre (Compt. Rend. 149 and 150: 1909) claims to have sterilized 

 liquids by the Schumann rays. He made no study of the biological effects of the 



of Schumann rays. On this point see Lyman (28). 



