THE EFFECTS OF CARBON DIOXIDE ON THE EGGS 



OF ASCARISi 



THEOPHILUS S. PAINTER 



(Instructor in the Sheffield Scientific School) 

 From the Osborn Zoological Laboratory, Yale University 



FIFTEEN TEXT FIGURES AND THREE PLATES 



The material upon which the present study is made was 

 placed in carbon dioxide on July 14, and removed on October 9, 

 of the same year (1913). Professor Boveri, in an attempt to 

 keep the eggs of Ascaris for a long time without allowing them 

 to undergo development, had a number of smears- from one female 

 placed in a stoppered glass jar. The air of the jar was then re- 

 placed by passing a current of carbon dioxide through it for an 

 hour and a half and, after sealing it carefully to prevent the 

 escape of the gas, it was placed in a basement room in the Zoo- 

 logical Institute at Wiirzburg. 



At the time the eggs were placed in the gas, no ill effects were 

 anticipated, consequently, no control smears were preserved 

 to show the exact nuclear condition in which the eggs were 

 at that time; and, after they were removed from the gas, they 

 were placed directly on ice where they remained until used. 

 When a few smears were allowed to undergo full development 

 later, it was found that only part of the worms were normal. 

 Professor Boveri called my attention to the fact and placed the 

 material at my disposal with the suggestion that I determine 

 the cause of the abnormal development which part of the worms 

 showed. 



Although the material for this study was obtained in Wiirz- 

 burg, the greater part of the work has been done since my return 



1 A preliminary note on this subject has been published by the author (1914). 

 ^ The smears were made on ordinary microscope slides according to Boveri's 

 well known method. 



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THE JOURNAL OP EXPERIMENTAL ZOOLOGY, VOL. 19, NO. 3 



