128 David Day Whitney 



IV CONDITION OF THE YOUNG ANIMALS WHICH DEVELOPED 

 FROM CENTRIFUGED EGGS 



If the materials of the egg which are differentiated into zones 

 by the centrifugal force are important formative substances their 

 displacement and their different location in the first cleavage stage 

 ought to cause abnormalities in the embryos and in the mature 

 animals which develop from such eggs. 



The following experiments which are only a few of those carried 

 out will serve to indicate to what extent the embryos form centri- 

 fuged eggs were affected by the displacement of the materials. 



Experiment I. January ii, 1908, at 8:30 p.m., many females 

 were centrifuged about twenty thousand revolutions and then 

 placed in a watch glass containing tap-water and allowed to lay 

 their eggs. At 10 p.m., thirty-seven eggs were isolated. 



January 13, at 9:30 a.m., there were in the dish thirty-two 

 apparently normal young females, three winter eggs and two dead 

 parthenogenetic eggs. 



Experiment V (Control). January 21, at 10 p.m., two hun- 

 dred and eighty eggs that had been laid by females which had not 

 been centrifuged were isolated in a watch glass containing tap- 

 water. 



January 22, at 8 p.m., two hundred and forty normal young 

 animals were removed from the dish. 



January 23, at 11 a.m., six normal young removed and of the 

 thirty-four unhatched eggs which remained thirty-one were winter 

 eggs and three were dead parthenogenetic eggs. 



Experiment XI. March 14, 7:45 p.m., several hundred females 

 were taken from the culture jar and placed in a watch glass con- 

 taining tap-water. No eggs had been laid by 8 p.m. These 

 animals furnished material for the following experiments. 



Lot A. At 8:35 p.m., twenty-five eggs which had been laid 

 since 8 p.m., were isolated and centrifuged twenty thousand 

 revolutions. 



March 15, at 12:40 p.m., sixteen young normal females were 

 taken out of the dish and nine unhatchedeggs remained. At 9 p.m. 

 the nine eggs were still unhatched. March 16, at 10 a.m., two of 



