GENETICS: THE HERITABLE TRANSMISSION OF CATALYSTS 177 



of intermediate waste products of the same kind as the tissues from 

 which it arose gave off before. These products would act as a hormone 

 on the gametocytes, stimulating the factors which in the next genera- 

 tion would control the development of frontal bone and adjacent 

 tissues. ... If the factors in the gametes were thus stimulated they 

 would, when they developed in a new individual, produce a slightly 

 increased development of the part which was hypertrophied in the 

 parent soma. No matter how slight the degree of heredity effect, if 

 the stimulation was repeated in every generation . . . the heredity 

 effect would constantly increase until it was far greater than the direct 

 effect of stimulation." 



Starling formed the word "hormone" from a Greek root mean- 

 ing "to stir up, or excite," and Cunningham uses the term in its 

 original meaning, which is lost sight of in speaking of "endo- 

 crines" produced by "glands of internal secretion." Certain sub- 

 stances, ordinarily regarded as waste products of cellular metab- 

 olism, are known to affect the activities of organs, and have been 

 called parahormones. Thus carbon dioxide activates the respiratory 

 center of the medulla and is administered with oxygen to avoid 

 respiratory collapse; and the normal heart-beat of some lower 

 vertebrates (e.g., sharks) seems to depend upon a certain concen- 

 tration of urea. 



While much is known as to the effects produced by hormones, 

 little is known about the mechanism whereby these effects are 

 produced. It appears that a probable explanation in many cases 

 may be based on catalyst modification, including inhibitions and 

 the formation of new catalysts. Alteration in membrane perme- 

 ability is another factor, and from this many catalyst possibilities 

 might later emerge. 



REFERENCES 



1 Chem. Eng. News (1946) 24, 1369, Westinghouse Forum address. 



2 Science, 66, 84-87. 



3 See also Chapter 4 for the work of Dr. William J. Robbins (N. Y. Botanical 

 Garden) on the demands of molds for vitamins and similar trace substances. 



*Zeit. physiol. Chem. (1932), 210, 33. 



5 See P. Rothmund, "Photosynthesis," in Alexander's "Colloid Chemistry," Vol. 

 V, pp. 600-610. 



e Ibid., pp. 610-667. 



7 See C. Correns, "Nicht mendelnde Vererbung," in Handbuch Vererbungswiss., 

 Berlin, 1937. 



8 "Heredity and Environment," 1919. 



9 /. Heredity (1938), 29, 323-329. 



10 "Colloid Chemistry," Vol. V, p. 573. 



