'0 



NEUTRON EFFECTS ON ANIMALS 



the activity was still below the pre-irradiation level seven weeks after 

 the time of exposure. 



In another experiment a rabbit was given a total dose of 112 n Avhich 

 consisted of two single doses of 5() n in Box No. 7 with an interval of ten 

 days between exposures. Two weeks after the last dose had been given 

 the serum phosphatase activity was found to be approximately 40 per cent 

 of the pre-irradiation value. 



A similar decrease in the serum enzyme level was observed when animals 

 were subjected to larger amounts of radiation (300 n) given in small daily 

 doses (10 n) in Box No. 4. Eight rabbits on which enzyme estimations 



r) 

 CO 



c_j 



CD 



D:: 

 Q_ 



'5" 



CD 



re 





50 



20 



10 







PRE-WR/IDIATION 

 PCRIOt i 







50 



10 20 30 40 



dAYS AFTEF IRRADIATION 



Fig. 2. Serum alkaline phosphatase activity in raljbits before and after irradiation 

 with neutrons. Dose: 56 n in Hox \o. 7. 



were performed 4 to 8 weeks after the completion of such a treatment 

 possessed an average activity of 1 1 .2 imits (range, 7.0-17.8) while a group 

 of ten normal rabbits gave an average of 25.1 units (range, 18.2-31.0). 



During the course of this work on rabbit serum phosphatase activity, 

 the serum of each of two animals for \\hich alkaline enzyme data are shown 

 in Fig. 2 was examined for possible effects of radiation on serum acid phos- 

 phatase activity. Estimiations were carried out by the method of Huggins 

 and Talalay (9) except that one-fourth the amounts of test -solution and 

 reagents was used. Serum samples were diluted to twice their volume 

 with distilled water just before use. Determinations made at intervals 

 equal to those shown in Fig. 2 showed no significant changes in the acid 



