132 STUDIES IN ELECTRO-PHYSIOLOGY: 



concerned, and in it there subsequently become effective 

 the same forces of Nature which in other combinations 

 constitute the vital forces of an organ. . . . We are 

 warranted in regarding the so-called spontaneous or 

 independent periodic movements " (in plants) " as phe- 

 nomena of irritability, just as animal physiologists place 

 the periodic pulsations of the heart in the series of phe- 

 nomena of animal irritability. ... I have repeatedly had 

 cause to refer to certain resemblances between the phe- 

 nomena of irritability in the vegetable kingdom and those 

 of the animal body, thus touching a province of investiga- 

 tion which has hitherto been far too little cultivated." 



Consideration of enzyme action does not come within 

 the scope of these studies, but it appears to be common 

 to both animal and plant. According to Vines the chief 

 kinds of enzymes which have been found in plants are : 



** (1) Those which act on carbohydrates, converting 

 the more complex and less soluble carbohydrates 

 into others of simpler composition and greater 

 solubility. 



" (2) Those which act on fats, decomposing them into 

 glycerine and fatty acid. 



" (3) Those that act on glucosides, glucose being a 

 constant product. 



" (4) Those that act on the more complex and less 

 soluble proteids, converting them into others 

 which are more soluble and probably less com- 

 plex, or decomposing them into non-proteid 

 nitrogenous substances (amides, etc.)." 



As regards a comparison of fats in animals and plants, 

 Sachs showed as long ago as 1858 that in the germination 

 of seeds containing fat, a transference of the fatty oils from 

 the cotyledons, or from the endosperm into the growing 

 parts of the seedling, appears to take place, and this was con- 

 firmed by chemical analysis by Peters. In his twenty-first 



