136 NEUTRON EFFECTS ON ANIMALS 



absorption spectra of the blood plasmas from some of the numerous ir- 

 radiated animals available. 



The probable effect of the neutron irradiation of an animal on its hemo- 

 globin and, therefore, on the absorption spectrum of the hemoglobin does 

 not, however, appear to be as easily predictable. While red blood cells 

 have been found to be radioresistant, sufficiently large doses of X-radiation 

 cause increased permeability of the cells with increased tendency to hemol- 

 ysis (8). There also is some evidence, though not completely substan- 

 tiated, that therapeutic doses of X-rays bring about an increase in average 

 red blood cell volume and, further, that irradiation produces a wave of red 

 blood cell regeneration (8). There does not appear to be any similar pub- 

 lished evidence as to the effect of neutron irradiation on red blood cells. 

 Neither has any statement been found of the effect, if any, of X-radiation 

 or neutron radiation of an animal on blood hemoglobin itself. 



It does not seem probable that such irradiation would affect hemoglobin, 

 so that no difference between the absorption spectra of hemoglobin obtained 

 from neutron-irradiated and from non-irradiated animals would be ex- 

 pected. The availability of irradiated animals and the rapidity with 

 which absorption data are obtainable by means of echelon cells, again 

 made a test of the conclusion worthwhile. 



EXPERIMENTAL 



Animals. All the rabbits used to provide blood for this work were male 

 white rabbits weighing not less than four pounds, maintained on a diet of 

 "Purina Rabbit Pellets" and water. Except for the "normal" (i.e., un- 

 treated and non-irradiated) animals, the rabbits had been used in the course 

 of another study having as its object the determination of the effects of 

 mononucleotides on the white blood cell count of normal and irradiated 

 rabbits. Consequently some of the rabbits whose bloods were used to 

 obtain the absorption data reported here had received daily intramuscular 

 injections of a mononucleotide mixture ("Pentnucleotide", Smith, Klein 

 and French, Philadelphia, Pa.) or of yeast adenylic acid (Schwartz Labora- 

 tories, Inc., New York, N. Y., lot number HA 4525) in addition to neutron 

 irradiation. Others had received the injections but no irradiation, while 

 still others had received neutron irradiation without any injections. 



Blood sample!- from two dogs used in another study (4) (dogsC-1 andC-4, 

 3 and 6 days after tl e completion of their irradiation) were also examined. 



Irradiation. The details of neutron production and of irradiation have 

 been described elsewhere by Enns et al. (9). The animals received their 

 daily neutron irradiation in approximately 2 hours usually in one continuous 

 dose although some received intermittent irradiation (over approximately 

 the same time) the interruptions being necessitated by the removal of 



