﻿BOVIE— SCHUMANN RAYS 



15 



was allowed to act for a few seconds on an amoeba which was 

 moving very rapidly across the field of the microscope. The 

 amoeba became quiet during the exposure. As soon as the light 

 was turned off, motion was resumed, but only part of the amoeba 

 moved away; a part of the protoplasm was coagulated and was 

 left behind. The exposure was continued in this way, a few seconds 

 at a time, killing a part of the amoeba at each exposure, until only 

 the nucleus and a small mass of surrounding protoplasm remained 

 alive. A final exposure killed this. The length of exposure neces- 

 sary to bring about these changes varied from 30 to 100 seconds 

 with the hydrogen discharge tube carrying 29 milliamperes. As 

 previously stated, the entire exposure was not made at one time, 

 but at intervals, so that the experiment often extended over an 

 hour. The changes produced by the light could thus be more 

 carefully observed. 



Infusoria are very quickly cytolyzed by the rapid vibrations of 

 these ultra-violet rays. The nature of the cytolysis varies greatly 

 with the species, and in some of the minor details it varies with the 

 different individuals. The writer has observed three kinds of 

 photocytolysis in ciliated infusoria: (1) a cytolysis which is accom- 

 panied by the formation of vesicles on the surface; (2) a cytolysis 

 in which some of the internal portions of the protoplasm coagulate; 

 and (3) a cytolysis in which some protoplasm disintegrates directly. 

 The first two types of cytolysis were observed in Colpoda-like forms, 

 and the third type was observed in Stylonychia. 



1. Cytolysis by the formation of vesicles. — The cytolysis is, in 

 general, like that of Paratnoeciutn in distilled water, in weak alkali, 

 and in 5 per cent alcohol, as described by Wulzen (39) . When a 

 Colpoda-tike infusorian is exposed to the light from the discharge 

 tube carrying 18 milliamperes there is first an increase, then a 

 decrease, in the rate of motion of the organism. Soon vesicles filled 

 with a clear liquid begin to form on the surface of the animal. The 

 infusorian loses its original shape and swims in circles. A vesicle 

 may continue to grow until it is larger than the original organism, 

 or it may increase in size for a short time and then slowly shrink 

 and disappear. As one vesicle is shrinking, others may be forming 

 at some other part of the surface of the organism. If the exposure is 



