INFLUENCE OF RADIO-ACTIVITY. 351 



of influence of « activity, which can travel through 7 cms. of air, 

 but less than one cm. of water. This was the period of the creation 

 of a gigantic fauna and flora. 



As soon as organisms had developed their primitive vascular 

 system the effects of radio emanations on the cul-de-sac, which 

 comparative anatomists assign as the progenitor of the lungs, 

 would be to render its lining walls hyperaemic, and here no actual 

 radio-activity could act, except filtered through the body walls. 

 This hyperff>mic cul-de-sac would increase the organism's power 

 of assimilation of oxygen direct from the atmosphere, until in place 

 of the primitive amphibian a purely aerobic type was established, 

 and life was capable of support on dry land. 



Life once established on dry land was for the first time acutely 

 within the sphere of all forms of radio-activity — i.e., a, /3, and 

 activity due to the fact that « activity has its greatest scope in the 

 atmosphere, penetrating 7 cms. of air ; but different individuals 

 were exposed to widely different intensities of activity as they 

 spread over the surface of the earth and exhibited corresponding 

 degrees of reaction, since the intensity of activity in any locale 

 depended on the amount of radio-active substance present, the 

 thickness of the organic deposit, and the degree of evolution of 

 elements possessing high atomic weights and corresponding 

 inhibitory powers. The exposure of groups of individuals to 

 different intensities during succeeding generations naturally caused 

 different modifications in the progeny, although descended from 

 the one species, and this must have been a factor in evolution 

 leading to the establishment of different types for different localities. 



The u activity caused reactions only in the superficies of an 

 organism due to the coefficient of absorption, and the effects were 

 an increase in the superficies, causing a thickened integument ; and 

 probably the positive electric charge of « activity had a kata- 

 phoretic action, and by the ionisation of various salts in the super- 

 ficies aided life then extant in developing the enormously thickened 

 dermal coverings which were characteristic of this age. 



Irritative reaction to radio-activity was then predominant. 

 Bohn, Perthes and Schafer have shown that in a single generation 

 pathological monsters of increased size with thickened, contorted 

 skins are evolved after exposure to radio-irritation in the laboratory. 

 It is therefore probable that successive generations exposed in 

 nature to activity, similar though diminished in order not to 

 destroy the reproductive power, increased in size, and radio- 

 irritation was probably an important factor in the general increased 

 size of the fauna of this period. 



As organisms increased in size they were ipso facto in greater 

 part removed from the sphere of a activity, and were exposed 

 solely to 13 and 7 activity except in their distal parts or when 

 their habits brought them close to the ground. These distal parts 

 ultimately became the only areas which exhibited the character- 

 istics of " irritation, c./., the legs of birds and the hoofs of the 

 ungulents. 



