THE PROBLEM OF ACTIVATION 253 



as the best acid reagent, as it appeared to possess a 

 particularly strong coagulative effect; ammonia was used 

 as alkali. He still found, however, that the method 

 did not succeed in sea- water, and finally, for reasons 

 that need not be considered, adopted a mixture of 

 70 per cent sea-water and 30 per cent of a solution of 

 saccharose estimated to have the same osmotic pres- 

 sure as the sea-water. To 50 c.c. of this mixture he 

 added twenty-eight drops of a u decinormal' : solution 

 of tannin; the eggs were placed in and left five to six 

 minutes; then thirty drops of N/io solution of ammonia 

 were added to neutralize the acid and to render the 

 mixture slightly alkaline. After an hour the eggs were 

 washed and allowed to develop in sea-water. Delage 

 states that as many eggs may develop by this method 

 as by fertilization, and he even raised some larvae 

 through metamorphosis. 



The method is thus very complex and inevitably 

 suggests the question whether it acts according to the 

 theory of causing a coagulation followed by a lique- 

 faction. Miss Lloyd (1914), working under Loeb's 

 direction, has made an analysis of this method. She 

 points out that the sugar solution employed was strongly 

 hypertonic as compared with sea-water and showed 

 that the tannic acid is not necessary. The tannic acid 

 employed by Delage was really a 1/60 molecular solution, 

 according to later views of its molecular structure, instead 

 of "decinormal," as Delage supposed, and hence the 

 ammonia added renders the solution strongly alkaline. 

 The activation is therefore attributed by this author to 

 the hypertonic action of sugar solution combined with 

 the strong alkaline reaction of the medium, both of which 



