808 



SCIENCE 



[N. S. Vol. XXXVI. No. 937 



changing its form? How is it that a mil- 

 lion muscle cells remain alike, collectively 

 ready to respond to a nerve impulse? If 

 germinal preformation answers the ques- 

 tion, the nervous system is relieved of any 

 responsibility for the maintenance of or- 

 ganization in the muscle tissue. The nerv- 

 ous system exercises occasional instan- 

 taneous effects upon the muscle, resulting 

 in one particular kind of activity. So far 

 as this relation is concerned, there is no 

 evidence of general control exerted by nerv- 

 ous tissue over muscle tissue. Even the 

 more or less continuous tonic effect of 

 nerve on muscle does not prove the exist- 

 ence of any control beyond the observable 

 tonic effect itself. 



With the case of internal secretions the 

 matter stands much the same. That a sub- 

 stance poured by one gland or tissue of the 

 body into the blood stream may produce 

 most important and specific effects upon 

 other tissues or organs has been demon- 

 strated beyond doubt. The secreted sub- 

 stance may be one in whose absence certain 

 definite abnormal conditions arise, as in the 

 case of the thyroid. Or it may be one 

 whose presence is somehow connected with 

 the perfectly normal development of an 

 organ, as in the relation between gonads 

 and secondary sexual organs. But in all 

 these relations which are established by the 

 transmission of nervous impulses or specific 

 substances from one part of the body to 

 another, we find no answer to the ques- 

 tion which we have stated. Upon the con- 

 trary, .the more of these relations we dis- 

 cover, the more intricate does our problem 

 become, for it is precisely these relations 

 which constitute organization. They are 

 the materials of our problem, not evidence 

 toward its solution. 



Any one of these relations is open to 

 either of the two interpretations which I 



have stated. View the animal, if possible, 

 without the prejudice which arises from 

 the knowledge that it is an organism. 

 View it as if it were a non-living dynamic 

 complex. The nervous system at once loses 

 its paramount importance. It appears as 

 a system coordinate with several other sys- 

 tems. It no more controls other systems 

 than it is controlled by them. True, cer- 

 tain conspicuous events in muscle are con- 

 ditioned by something that happens in 

 nervous material. But, so far as we can 

 clearly see, it may be equally true that 

 every operation and event in the nervous 

 tissue is conditioned more or less directly 

 by activities going on in other systems or 

 otherwise outside of the nervous system. 

 The nervous tissue appears as a group of 

 elementary organisms of peculiar form, 

 existing in an environment in which they 

 find the materials requisite for their main- 

 tenance. They receive more or less inter- 

 mittent influxes of energy from this en- 

 vironment and, in turn, discharge it in a 

 more or less modified form. In muscle 

 tissue we see another group of elementary 

 beings, muscle cells, whose habitual en- 

 vironment subjects them to certain ener- 

 getic actions to which they exhibit a fiixed 

 type of reaction. And so it is throughout 

 the whole organism. The substance or the 

 energy which is given off by one element 

 as a by-product or a waste product of its 

 activities becomes a peculiarity of the en- 

 vironment in which other elements habitu- 

 ally carry on their existence. It is a vast 

 symbiosis. It is comparable to the relation 

 which exists between the plant life and the 

 animal life of the globe. Green plants 

 need carbon dioxide and give off oxygen. 

 Animals need oxygen and give off carbon 

 dioxide. And so they live successfully to- 

 gether. But would any one venture to 

 propose that the internal organization of 



