APPENDIX 89 



water. The reagents were used in different dilutions and for varying lengths 

 of time. The treatment was applied to eggs not more than twelve hours old; 

 mostly to eggs but a few minutes to a few hours old. Five hundred or more 

 lots of untreated, unfertilized eggs were observed in order to determine the 

 extent of normal parthenogenetic development. The eggs of half a dozen silk- 

 worm races were used and all the eggs were preserved from time of laying until 

 their death. 



As it seemed to me that most of the favorable results obtained by Tichomiroff 

 and Quajat were obtained by treatments which had as common effect a dehydra- 

 tion (such as high temperature, friction, sulphuric acid, etc.) I attempted to test 

 this first by using various dehydrating agents, especially a dry chamber in which 

 the eggs could be submitted for from a minute or two to several hours to a 

 nearly perfectly dry atmosphere. Friction, heat, sulphuric acid, phosphoric 

 pentoxide and glacial phosphoric acid were also used as dehydrating agents. 

 At the same time other treatment, not dehydrating, was used on other lots and 

 gave results hardly less favorable than the dehydrating. The results at the end 

 of this first course of treatment seemed to point to the hydrogen ions as the most 

 likely development-inciting factor. Hence various agents agreeing in containing 

 hydrogen ions though differing radically in other particulars were used. The 

 results gave no encouragement to the hydrogen ion theory. In fact I have not 

 been able to come to an opinion concerning the true causa efficiens in the matter. 

 My results simply show to me that various stimuli, acid or alkaline, dehydrating 

 or non-dehydrating, possessing or not possessing hydrogen ions, are able to 

 increase materially the proportion of eggs that develop in lots of unfertilized 

 eggs. 



The data of the experiments are given in considerable detail. 



