1 66 TEE POPULAR SCIENCE MONTHLY 



the view that the functions of man's brain and nervous system were 

 specifically different from those of the lower animals. After centuries 

 of hopeless wandering in a labyrinth, investigators at last picked up 

 the ariadnian thread that connects the behavior of the simplest organ- 

 ism with the complex mental life of man, and students have come to 

 realize that in the simpler structure and more easily analyzed functions 

 of ameba, jelly-fish, crab or fish, is to be found the key that will eventu- 

 ally open the book in which we may read intelligently concerning the 

 most complex psychic manifestation. 



This change in our point of view is not only of philosophic but of 

 great practical value. The student of the brain is no longer a Sisyphus. 

 Investigators now know that a fact discovered in relation to the nervous 

 system of worm or jelly fish may unlock some of the secrets of the 

 physiology of man's brain. The advance from the study of the simpler 

 reactions of the lower organisms to those of the higher animals is made 

 by easy stages, and the knowledge that the continuity of the chain is 

 unbroken is a source of hope and inspiration. Already the nervous 

 system has been deprived of the mysterious specific properties which 

 once it was supposed to possess. Eminent physiologists tell us that it 

 has only those properties which are found to be distinctively character- 

 istic of protoplasm, the physical basis of life. The capacity for receiv- 

 ing stimuli coming from the external world, of transforming, transfer- 

 ring and storing these impressions is characteristic of living organ- 

 isms. Plants have the power to pick up and transmit a stimulus. An 

 example of this power is seen in the closure of the leaves of the sensitive 

 plant after being touched. As far as is known, however, plants do not 

 have a differentiated nervous system, but between the various cells of 

 which they are composed there are countless connections probably form- 

 ing paths for the conduction of impulses. These conditions are not un- 

 like those found in embryos of the higher animals at the time when the 

 movements of heart and body have already begun, but before nerves have 

 developed. 



The study of the lowest organisms teaches us that the conductions of 

 nervous impulses occur independently of nerves. More recent studies 

 have led investigators to believe that the nervous system does not in any 

 sense create function, but is to be regarded merely as the great regu- 

 lator, the transforming apparatus called into existence to assist in pre- 

 serving the equilibrium of each living organism, amid a play of ener- 

 gies, light, heat, electric waves, etc. As long as the equilibrium is un- 

 disturbed we say that the body is in a state of rest, but let that balance 

 be disturbed by any stimulus and a reaction takes place. In compari- 

 son with other animals, some of our sense preceptions are very limited 

 as our end organs or receptors are only attuned to pick up waves of cer- 

 tain lengths. Other living organisms, as, for example, many insects, 



