January 21, 1910] 



SCIENCE 



93 



activity as an association of engineers, that 

 is, as a strictly or even quasi professional 

 organization, but from its relations with 

 the other sections, and that its own activi- 

 ties might well be somewhat curtailed if 

 more intimate relations could be initiated 

 and stimulated with those other sections; 

 and that it should endeavor to present to 

 its members not technical engineering sub- 

 jects, but rather scientific subjects in 

 branches seldom discussed in the technical 

 engineering societies. Let us remember, 

 then, that engineering is a profession, but 

 that it is founded upon science; that the 

 engineer should be at heart a true scientist, 

 and thoroughly imbued with the scientific 

 spirit. Further, that this association is 

 not a professional society, but a scientific 

 one, and that we come here rather as scien- 

 tists than as engineers; that through our 

 meetings and our contact with scientists in 

 all branches, we may go forth to our daily 

 practical and business work more thor- 

 oughly imbued than ever with a sense of 

 the importance of our profession, and bet- 

 ter able to apply economically the ma- 

 terials, forces and laws of nature in the 

 service of man. 



George F. Swain 

 Harvard Univeksity 



V^, 



TEE CHEMICAL REGULATION OF THE 



PROCESSES OF THE BODY BY MEANS 



OF ACTIVATORS, KINASES AND 



HORMONES ^ 



At the time of Sir Charles Bell physiol- 

 ogists were beginning to realize the great 

 importance of the nervous system as a 

 mechanism for regulating and coordinating 

 the varied activities of the body. To use 

 his own expression, "The knowledge of 

 what is termed the economy of an animal 



'Address of the vice-president and chairman of 

 Section K — Physiology and Experimental Medi- 

 cine. American Association for the Advancement 

 of Science, Boston, December 28, 1909. 



body is to be acquired only by an intimate 

 acquaintance with the distribution and uses 

 of the nerves." Since his time experi- 

 mental investigations in physiology and 

 clinical studies upon man have combined 

 to accumulate a large fund of information 

 in regard to the regulations and correla- 

 tions effected through nervous reflexes. No 

 one can doubt that very much remains to 

 be accomplished along these same lines, but 

 in recent years we have come to understand 

 that the complex of activities in the animal 

 body is united into a functional harmony, 

 not only through a reflex control exerted 

 by the nervous system, but also by means 

 of a chemical regulation effected through 

 the blood or other liquids of the organism. 

 The first serious realization of the impor- 

 tance of this second method of regulation 

 came with the development. of our knowl- 

 edge of the internal secretions during the 

 last decade of the nineteenth century. The 

 somewhat meager information possessed at 

 that time in regard to these secretions de- 

 veloped in the fertile imagination of 

 Brown-Sequard to a great generalization, 

 according to which every tissue of the body 

 in the course of its normal metabolism fur- 

 nishes material to the blood that is of im- 

 portance in regulating the activities of 

 other tissues. This idea found a general 

 support in the facts brought to light in 

 relation to the physiological activities of 

 the so-called ductless glands, and subse- 

 quently in the series of remarkable dis- 

 coveries which we owe to the new science 

 of immunology. In recent years it has 

 been restated in attractive form by Sehief- 

 ferdecker in his theory of the symbiotic 

 relationship of the tissues of the body. 

 According to this author we may conceive 

 that among the tissues of a single organism 

 the principle of a struggle for existence, 

 which is so important as regards the rela- 

 tions of one organism to another, is re- 



