THE CYCLE OF LIFE 385 



Very striking experiments have been made by M. Bataillon 

 on frogs' eggs, and confirmed by M. Henneguy. Under 

 proper precautions the eggs were taken from a frog, placed 

 in a flat dish, pricked with a needle of platinum or glass, 

 and then covered with a layer of water which had been 

 sterilized by heat. In about four hours the eggs began to 

 segment, and about a fifth of them did it normally. Out 

 of a thousand eggs, a hundred and twenty hatched into 

 tadpoles, and one of these lived till it was about three months 

 old and almost a perfect frog. As it has been remarked, 

 ' in the hands of these physiologists, the little needle was as 

 potent (or almost as potent) as Aaron's rod '. 



In one of his experiments, Bataillon took a piece of a 

 string of toad's spawn with as little jelly as possible, put it 

 in a dry dish, bathed it with a little blood, and made little 

 punctures in the eggs. They segmented ' magnificently ', 

 and the frog's blood works as well as the toad's, and better 

 than the spermatozoa of the frog ! According to Bataillon, 

 pricking the eggs, or exposing them to vapour of chloroform, 

 or subjecting them to electric discharges, and the like, 

 may be sufficient to activate the eggs and induce some 

 cleavage. But if embryos and larvae are to be developed, 

 there must be something more ; there must be an intro- 

 duction of some organic, apparently nuclear, matter, which 

 probably exerts a catalytic influence. Thus frogs' eggs 

 moistened with blood and then pricked will develop into 

 larvae. The pin-prick plus the introduced blood corpuscle 

 take the place of the spermatozoon in normal fertiliza- 

 tion. 



Fritz Levy followed the method of pricking the frogs' 

 eggs with a platinum needle, which was sometimes first 

 dipped in salt or in the blood of the mother. He repeatedly 



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