286 Studies in tli< Physiolofiti of Fertilization 



their own volume of watn-. At lengths of time vaiying fnjm 65 — 120 

 minutes portions of this water were drawn off and used in the experi- 

 ments. At the time of the last fertilization made, this water was still 

 green to a-Naphtholphthaleiii. Definite equal amounts of Ciona sperm- 

 suspension (see Table XXVII) were added to (1) 2 cc. of plain sea-water, 

 and (2) 2 cc. tif the Strongylocentrotm egg-water, this time not contain- 

 ing any Strongylocentrotus eggs. 10 cc. water was then added to each', 

 and they were poured on to separate equal amounts of Gioud eggs. 'I'he 

 experiments wei'e made double. 



TABLE XXVII. (40.16.5.) 



troius 

 Water egg-water 



Egg- water 65 minutes on eggs... 3 drops sperm ... 28 77 



, 3 drops sperm... 20 73 



Egg-water 80 minutes on eggs 

 Egg-water 95 minutes on eggs 

 Egg-water 120 minutes on eggs 

 Egg-water 120 minutes on eggs 

 Egg-water 120 minutes on eggs 



) 1 cc. sperm ... 74 9t; 



(3 drops sperm... 2fi 65 



I 1 CO. sperm . 31 99 



( 3 drops sperm ... 60 86 



} 1 cc. sperm ... 91 100 



\ 3 drops sperm . - 1 73 



/ 1 cc. sperm ... 8 79 



( 3 drops sperm... 80 lOO 



I 1 cc. sperm . 94 100 



In all the e.xperiments of Table XXVII the Cioita sperm which had 

 been treated with Strongylocentrotus egg-water had its fertilizing pow(;r 

 increased to a marked extent. 



As has already been stated, there are two possibilities to account for 

 the absence of this effect in the experiments of Tables XXIII and 

 XXVI. It would seem, howevei-, that the possible entanglement of the 

 spermatozoa in the jelly of the Echinoid eggs present, although it might 

 conceivably account for the complete inhibition of fertilization in Table 

 XXIII, could hardly cause no change in the percentages, as seen in 

 Table XXVI. Considering the .strong inhibitor}' effect of the presence 

 of small quantities of acid (jn the fertilizing power of spermatozoa, as will 

 be shown (jn p. 294, it is extremely f)robable that the cause of the 

 anomalous results obtained in these two experiments was the presence 

 of acid in the egg- water. It was shown that the egg- water of Table 

 XXVI gave a pink colour with a-Naphtholphthalein at the moment 

 when it was used. Thus, jircsuniably owing to the fact that it had 



' In Experiments 5 and 6 the sperm was added to 5 ec. (1) water, (2) egg-water, after 

 which -5 cc. water was added to eacli. 



