

THE PHYSIOLOGY OF THE NEURON. 519 



which are not in contact, hut sufficiently close, one to the 

 other, as to make it possible, when required, for a nerve-impulse 

 to cross the interval between them. These facts have been 

 satisfactorily established by modern methods, especially 

 through the labors of Golgi and Ramon y Cajal. But the 

 manner in which the gap between the processes is closed i.e., 

 how the impulse passes from the terminal brush of the axon 

 of one nervous element to the dendrites of the next is still 

 to be determined. It has been suggested, however, that the 

 processes behave, in a limited manner, as do the pseudopodia 

 of the amoeba, and that by a slight extension the interval 

 between the processes is closed. When the processes are not 

 in contact they are said to be in a state of "retraction/' Much 

 as such a function would facilitate and shorten our analytical 

 work could incontrovertible experimental facts be adduced to 

 sustain it, we are brought, by a review of the literature of the 

 subject, to recognize that such facts are not available. Indeed, 

 the majority of physiologists and neuro-histologists now con- 

 sider the question of "amoeboid .movements of the neuron" in 

 the light of a working hypothesis. 



There is one feature of the investigations in this direction 

 which may serve to throw more light upon the whole ques- 

 tion if one of the more prominent deductions submitted by 

 us in the present work is taken into consideration: i.e., the 

 fact that all drugs cause overactivity or insufficiency of the 

 adrenals. 



Much of the physiological work done in connection with 

 the neuron includes the administration of various toxics, 

 strychnine, chloroform, morphine, etc., and amoeboid move- 

 ments or other active manifestations of the protoplasmic proc- 

 esses are thus ascribed to the action of the drugs upon the 

 neurons per se, whereas, in the light of our views, the changes 

 of form witnessed should be ascribed to increased or reduced 

 blood-supply when toxic doses are given. To illustrate our 

 meaning we will give in outline an experiment which repre- 

 sents one of the key-stones of the entire theory, that of 

 Demoor. Before doing this, however, it may, perhaps, be well 

 to state that we will consider the terms "neuron" as applying 

 to the complete nerve-cell, including processes; "neuraxon" 



