64 OTTO GLASER. 



I wish to add, parenthetically, another mollusc, the oyster, and 

 two vertebrates, the fish, Fundulus heteroditus, and the frog, 

 Rana pipiens. 



Though we may derive comfort from a distribution so varied, 

 this in itself is no proof that the exudates are part and parcel of 

 the mechanism of fertilization. Moreover the original method 

 of demonstrating their importance is not free from suspicion. 

 To wash eggs until all traces of their exudates have disappeared 

 takes time; in the 1 8 to 36 hours necessary to accomplish this, 

 the eggs themselves may undergo serious deterioration. Their 

 failure therefore to develop if inseminated after washing cannot 

 be attributed offhand to the removal of the exudates. Yet the 

 original inference is correct 1 for the time required to remove the 

 exudates may be cut in half by the use of running sea-water. 

 By the use of charcoal 2 eggs may be freed from secretion com- 

 pletely in 3 to 4 hours; or, if the chorion is first removed, in 30 

 minutes. This falls well within the time limit within which 

 unwashed eggs show no impairment of fertility. More con- 

 vincing proof comes from experiments in which the fertility of 

 eggs partially sterilized by the removal of exudate is measurably 

 increased by the addition of freshly prepared secretion. Such 

 an experiment with Asterias eggs was first carried out by Miss 

 Woodward. Since then I have had an opportunity to verify 

 her results on the eggs of Echinarachnius parma. These in a 

 series of experiments were incompletely sterilized by the partial 

 removal of the exudate. In one of the experiments the eggs were 

 then divided into two lots; one of these was inseminated at once 

 and several hours after fell into two groups 59 per cent, abso- 

 lutely inactive ones and 41 per cent, in which development was 

 going on. The latter group, however, was in turn divisible into 

 cleavages patently anomalous and cleavages not distinguishable 

 from the normal, approximately, in the ratio of 2:1. The 



1 There is one reservation; complete removal seems to have certain irreversible 

 consequences. I have referred to the matter before. See this journal, Vol. 

 XXVI., p. 395- 



2 The use of charcoal in this connection was suggested by Dr. G. H. A. Clowes. 

 The suggestion was based on preliminary indications of the presence of enzymes 

 and on the well-known efficacy of charcoal in removing these from solution. See 

 Euler-Pope, "General Chemistry of Enzymes," p. 81. 



