NO. I 



IRRADIATED ASCARID 0\'A WRIGHT AND McALISTER 



A number of eggs sufficient to cover only the bottom of the dish was 

 used in order to prevent any overlapping and shadowing of eggs from 

 the ultraviolet light. After irradiation the eggs were transferred by 

 means of a clean pipette to culture dishes containing a i per cent 

 solution of formalin. As a control, a culture was made in i per cent 

 formalin on the same date as the first irradiation exposure and was 

 subjected to the same conditions of development as were the irradiated 

 cultures. Temperatures during the period of development varied be- 

 tween 30° and 35° C, as recorded on a thermograph chart. Table 3 

 gives the results of this experiment. In this series 400 ova were taken 

 for each count. 



Table 3. — Results of Exposure of Ova of Toxocara canis and Toxascaris leonina 



to Ultraviolet Light 



Series C — Exposed July 16, 18 and 20, 1934 

 Dosage — 137,000,000 ergs/cni"^ 



It will be noted that the exposure to ultraviolet light at a wave length 

 of 3022 A was the only exposure which produced any apparent toxic 

 effect on the eggs of either species. The counts indicated that only 20.5 

 per cent of the irradiated Toxocara ova reached embryonation as com- 

 pared with 65.5 per cent of the eggs embryonated in the control culture, 

 and only 1.5 per cent of the irradiated Toxascaris ova became em- 

 bryonated as compared with 42 per cent of the eggs embryonated in 

 the control culture. 



In this experiment the irradiated and control cultures were examined 

 daily under the microscope. A careful check was made on the develop- 

 ment of the cultures in an effort to determine whether there was any 

 lag in development in those ova which actually started to segment. No 

 such lag in development was noted. Those ova which segmented ap- 

 parently began segmentation as promptly as did nonirradiated ova in 

 the control culture. 



