96 NEUTRON EFFECTS ON ANIMALS 



was found in preliminary work to facilitate the removal of the bone mar- 

 row and its subsequent extraction. 



The bones were split longitudinally and the marrow removed with for- 

 ceps to a tared weighing bottle. After re-weighing, the bottle was kept 

 in an ice bath while portions of the marrow were removed for homogen- 

 ization. 



The marrow was homogenized in phosphate-buffered normal saline 

 (pH 7.3) containing 0.5 per cent lithium oxalate. Homogenization was 

 brought about by a 5-minute exposure of 2 g. portions of marrow in 6 ml. 

 of the above buffer to intense sound waves of 10.5 kc. produced by a Pierce 

 magnetostriction oscillator comparable to that described by Chambers and 

 Flosdorf (6). After each portion had been homogenized, it was removed 

 to a centrifuge tube kept in an ice bath. The process was repeated until 

 all of the bone marrow had been homogenized. The homogenate was kept 

 overnight in the ice bath and then centrifuged. The fat layer was then 

 removed and the ac^ueous extract filtered through sintered glass filters. 

 A portion of the filtrate was analyzed for total and non-protein nitrogen 

 and the remainder was dialyzed against four changes of buffer solution 

 in preparation for electrophoresis. The chemical data on the bone mar- 

 row extracts are summarized in Table IL The fact that approximately 

 twice the amount of protein was extracted from the marrow of the irradi- 

 ated animals as from the non-irradiated group is of doubtful significance 

 because of the small number of animals studied. The results of the electro- 

 phoretic experiments are given in Table ^ II, and the diagrams themselves 

 are presented in Fig. 2 and Fig. 3. 



A total of 30 to 40 minutes treatment in the magnetostriction oscillator 

 was required for total homogenization of the marrow although each frac- 

 tion required only five minutes. In order to determine whether or not any 

 protein changes were produced by exposure to intense sound waves, 

 plasma samples were similarly exposed for 30 to 40 minutes for rabbits B 

 and C and for 60 minutes for rabbits D and E. 



Pathology. On autops\' the non-irradiated rabbits, B, D, and E, showed 

 no gross or microscopic pathological change. Of the two irradiated ani- 

 mals, one, rabbit C which was sacrificed 12 days after irradiation, was 

 normal except for atrophy of the testes. However, the second irradiated 

 animal, rabbit A, was found in a comatose state only 20 hours after irradi- 

 ation. The plasma obtained from this animal had a milky opalescent 

 appearance which could not be readily cleared up, and in addition gave a 

 non-protein nitrogen value of 127 mg. per cent which Avas approximately 

 three times the value found in the other foiu- rabbits. On autopsy, this 

 animal showed grossly a marked diarrhea and a spleen blue-grey in color. 

 Microscopically the germinal centers of the lymphoid follicles of the small 



