BIO-ECONOMICS OF INTERNAL SECRETIONS 149 



implied constancy and regularity of exercise of the parts. 

 There are also internal secretions at particular times, and 

 Mr. Stiles tells us that 



we have the best of evidence that the adrenals can thus be thrown into 

 a temporary activity far beyond their ordinary performance. The par- 

 ticular occasion for this is one of stress and excitement. It has been clearly 

 proved that at such times the chief product of the adrenal cells (adrenin) 

 is increased in the blood. It has also been proved that this internal 

 secretion confers upon an individual the utmost command of his physical 

 resources. 



We may take it that great irregularity of glandular action, 

 commensurate with the irregularity of ill-gotten supplies, is the 

 norm amongst predaceous species, which, as the result, if they 

 have more excitement of life, are yet in the end left with 

 diminished strength and endurance, and with uncouth, ill-shapen 

 bodies. As regards the oiigin of Adrenaline, according to Prof. 

 Gowland Hopkins (see his Presidential Address to Section I., 

 Brit. Assoc., 1913), it is derived from one of the " aromatic " 

 amino-acids, i.e., in my view, from one of the " building stones " 

 specially hall-marked as of vegetable extraction. Prof. Hopkins 

 remarks in this connection : " Facts of this kind will form a 

 special chapter of bio-chemistry in the future." 



In the same address it is pointed out that in connection with 

 certain important proteid reactions, the carnivore behaves 

 differently to the herbivore,* the latter showing greater powers 

 of synthesis and of defence, which seems further to corroborate 

 my view that growth and evolution are determined according 

 to the varying degrees of Symbiosis existing between animal and 

 plant. 



* One of my French /oological critics (Annie Biologique, Vol. xxi.), evidently a believer 

 in " de qustibubs non est disputandum," finds fault with me for asserting that it makes a difference 

 in evolution whether a species habitually ingests animal or plant protein, and he thinks it doubt- 

 ful that my theory will cause "la biologic positive" to take a forward step. One must not, 

 however, abandon all hope. 



