THE PHYSICAL CHEMISTRY OF PROTOPLASM 233 



the chemical phenomena which are called " vital " and those 

 which take place in ordinary laboratory reactions are due to the 

 fact that the former are manifestations of the interchanges of 

 energy between the different phases of a heterogeneous colloidal 

 system, while the latter are governed by the laws of ordinary 

 stoichiometric combinations. 



ELECTRICAL PHENOMENA OF PROTOPLASM 



The investigations of this phase of the physical chemistry 

 of protoplasm have dealt almost exclusively with animal tissues 

 and reactions, and have included the study of such phenomena as 

 nerve impulses, muscular contractions, heart-beats, glandular 

 secretions, etc. Tissues which respond to nerve, or brain, con- 

 trol are, of course, not found in plants. But there is plenty of 

 experimental evidence to show that plant protoplasm carries 

 electrical charges and exhibits electrical phenomena which are 

 similar in character to those of animal tissues. In fact, it has been 

 shown that the contraction of the lobes of the Venus' fly trap, 

 when they close over an imprisoned insect, are accompanied by 

 electrical phenomena in the leaf tissues which are precisely similar 

 to those which take place in an animal muscle when it contracts. 

 It seems probable that many of the observations and conclusions 

 which have been derived from the study of the electrical dis- 

 turbances in animal tissues may later be found to have definite 

 applications to the vital phenomena of plant cells. Hence, it 

 seems proper to give some brief consideration to these matters 

 here. 



The statement has been made that " every active living cell is 

 essentially an electric battery," and it is believed that every activity 

 of living matter, such as the rhythmic contraction of the heart, 

 the passage of a nerve impulse, etc., is accompanied by an electric 

 disturbance in the protoplasm of the tissues in question. Experi- 

 mental proof of this electrical disturbance has been repeatedly 

 obtained, by connecting a delicate galvanometer in a circuit 

 through the living tissue which is undergoing different activities and 

 obtaining widely varying readings of the instrument as the different 

 phenomena are in progress, or by connecting the instrument with 

 muscular tissue and observing its fluctuations with either the 



