8 PROBLEMS OF FERTILIZATION 



He concluded that the seminal fluid acts by accel- 

 erating the vital processes; it enters the body through 

 pores and stimulates the action of the heart. This idea 

 offered no difficulty to one who believed that the organ- 

 ism was preformed in the ovum, and it was supported 

 by the observation that the beating of the heart was the 

 first observable movement of the embryo. Bonnet 

 suggested to him the problem: If the spermatic fluid 

 might stimulate the heart of the embryo in the process 

 of fertilization, why might not other fluids produce the 

 same effect? He was thus led to attempt the first 

 experiments on artificial parthenogenesis; he tried to 

 start the development of eggs by electricity, by the 

 action of extracts of all the various organs, by vinegar, 

 dilute alcohol, lemon juice, and other substances, all 

 without effect. 



It is interesting to see how his experiments led to 

 hypotheses, and these, even though wrong, to further 

 experiments, some of which, like his experiments on 

 artificial parthenogenesis, were not taken up again in 

 a fruitful way for over a century. 



His final experiments are those so often quoted as 

 furnishing the proof that fertilizing power resides in the 

 spermatozoon. He showed that, if diluted sperm be 

 filtered through a sufficient number of layers of filter 

 paper, the filtrate has no fertilizing power, whereas the 

 residue washed off the filter paper will fertilize. But 

 he did not himself draw the correct conclusion; he 

 says the experiment proves "that filtration removes 

 from spermatized water its fertilizing power, inasmuch 

 as the seminal fluid which was contained in it remains 

 on the filter papers, from which one can extract it by 



