144 A. RICHARDS AND A. E. WOODWARD. 



S2 It begins as a large number and decreases rapidly: in Sc its 

 successive values are 12, 5, 7 and 5, while for S2 they are 14, 8, 4 

 and 4. In S7 the values of d are smaller and decrease more 

 slowly, being 7,5,5 and 4. This suggests that the laws governing 

 the agglutination reactions by the various solutions are of dif- 

 ferent character. But in as much as this interesting result has 

 not been generally obtained it is not possible to attach special 

 importance to it at this time. It is given merely as suggestive. 



The data in the case of S7 indicate that the activity of the 

 fertilizin was decreased although the number of dilutions was the 

 same as in the control, because the number of seconds required 

 for the reversal of the reaction at unit concentration was much 

 larger than is usual; yet at a further dilution no reaction was 

 obtained. Also the undiluted solution did not hold the sperm in 

 agglutination as long as in the control. Furthermore, it may be 

 significant that the value of d for S7, as indicated above, are 

 smaller than in the case of the other solutions. 



Subsequent experiments along the same line gave similar 

 results. They show clearly that radiation by x-rays is capable 

 of changing the activity of fertilizin, and in general agree with 

 previous work that weak radiation is accelerative and strong 

 inhibitive. Some of our experiments were performed during the 

 latter part of the summer at the end of the breeding season and 

 there were irregularities in the results, but it is believed that these 

 irregularities may be attributed to the unsatisfactory condition 

 of both sperm and eggs at this season of the year and that the 

 statement above gives the true effect of radiation on fertilizin. 



Also during the latter part of the supimer the writers tested 

 the effect of x-radiation on fertilizin with regard to its power of 

 inducing auto-parthenogenesis. Due to the near end of the 

 breeding season these results are not entirely trustworthy, but 

 they agree fully on one point, namely, that the radiation effects 

 changes in the capacity of fertilizin to induce parthenogenesis. 



On August 10 a sperm agglutination experiment was performed 

 which possibly throws some light on the irregularity of the auto- 

 parthenogenesis and at the same time makes the auto-partheno- 

 genesis test doubtfully applicable for the radiation problem. 

 This experiment gave data showing that the radiation effects 



