EFFECT OF X-RADIATION ON FERTILIZIN. I4I 



The methods used in these experiments were largely those of 

 Lillie and Glaser. The solution used as a standard was prepared 

 according to the method of Lillie by "adding to a certain number 

 of 'dry' eggs, double their volume of sea-water, and with occa- 

 sional slight agitation allowing ten minutes to elapse. At the 

 end of this time the ova were precipitated by 100 revolutions of 

 the centrifuge and the supernatant fluid, a clear, golden liquid 

 in the case of Arbacia," was decanted, (Glaser, 14a). The 

 agglutination of fresh sperm in suspension by fertilizin in both 

 control and radiated solutions, was tested by the unit concentra- 

 tion method of Lillie, of which he says, (13&) "The agglutination 

 reaction of the sperm in the presence of this substance {Arhacia 

 fertilizin) is, as noted in previous studies, reversible, and the 

 intensity and duration of the reaction is a factor of the concen- 

 tration of the substance. The entire reaction is so characteristic 

 that it was possible to arrive at a unit by noting the dilution at 

 which the least unmistakable reaction was given. This was fixed 

 at about a five or six-second reaction, which is counted from 

 the time that agglutination becomes visible under a magnification 

 of about 40 diameters until its complete reversal. The unit is 

 so chosen that a half dilution gives no agglutination of a fresh i 

 per cent sperm suspension." Further details are given in his 

 recent paper ('14, pp. 526-528). One can best observe the details 

 of the reaction with the low power of the microscope. The 

 sperm suspension is mounted under a cover glass and the drop 

 of fertilizin added at the edge of the suspension by means of a 

 pipette. The entire process is observed through the microscope, 

 and the time elapsing before the complete reversal of the reaction 

 is carefully noted by means of a stop-watch. Thus it was 

 possible to determine the degree of activity of a given sample of 

 fertilizin, and by comparing radiated and non-radiated solutions, 

 to measure the effect of the radiation by x-rays. 



Another possible method of studying the effect is suggested 

 by the fact that fertilizin can be used to bring about the parthen- 

 ogenetic development of Arhacia eggs, the so-called auto-parthen- 

 ogenesis. The efficacy of fertilizin before and after radiation 

 in bringing about auto-parthenogenesis is a measure of the action 

 of the radiation on it. 



