ORGAN AND BODY SYSTEMS 513 



between the effects upon the nucleated cells (more sensitive) and the 

 non-nucleated cells. For cathode electron effects see Hausmann and 

 Zakovsky (140), Langendorff et al. (189). 



Kromeke (180) states that rabbits exposed over the whole body to 

 1 to 20 H.E.D., showed plainly a polycythemia, an increase sometimes as 

 high as 28 per cent in the red blood cells after a latent period of 3 to 5 

 days. In some rabbits, the highest red-blood-cell count was reached on 

 the 8th day, when there was an increase of about a million. This 

 decreased later and in some rabbits anemia developed. The hemo- 

 globin kept parallel to the red-blood-cell count, but the color index 

 dropped somewhat in the longer experiments due to the young cells. 

 The refractive index of the serum proteins usually decreased. There 

 was usually a leucopenia which was more or less transitory. Nucleated 

 red cells were not seen, nor were eosinophilic or basophilic cells ever seen 

 in the smears of the blood. There was a normal count of polychromato- 

 philic cells. Apparently the bone marrow had used up its reserve and 

 was making new cells. This would account for the drop in hemoglobin 

 and color index (180, 351). Some believe a stimulation of marrow cells 

 may even be produced (Bucky and Guggenheimer, 32). 



Bone Marrow. — The precursors of the circulating blood cells in the 

 marrow are sensitive to irradiation, perhaps even more so than the adult 

 lymphocytes, because of the relatively smaller dose that may be given 

 to them directly, i.e., through the bones (291, 334). The acute changes 

 which occur in the hemopoietic system of dogs following total destruction 

 of the bone marrow by 1700 r over the skeleton with the intestines pro- 

 tected, produces an acute agranulocytosis, a sudden disappearance of 

 platelets (7 to 8 days) and a sudden and fatal, diffuse, capillary hemor- 

 rhage within a circumscribed time interval (8 to 9 days after irradiation) 

 (334). The clinical picture is that of a normal active dog for 6 to 7 days, 

 then suddenly anorexia and occasional vomiting develop but no severe 

 intoxication. The circulating white-blood-cell counts decreased from 

 15,000 per mm.^ before irradiation to 25 to 200 (all polymorphonu- 

 clears and large mononuclear cells) on the sixth day and remained at the 

 extremely low level of 25 to 100 per mm.^ up to exitus. Doubling the 

 dosage or large transfusions did not change this sequence of events. 

 Gross and microscopic hemorrhages were found in most tissues. The 

 red blood corpuscles were well preserved throughout the experiment and 

 showed no hemolysis or increased fragility. There were no nucleated 

 forms, nor was there increase in reticulated forms. The platelets dis- 

 appeared from blood smears the day before exitus. This was probably 

 responsible for the diffuse hemorrhagic phenomena (383). Only an 

 occasional megakaryocyte was found in the spleen and none in the bone 

 marrow (334). The bone marrow was depleted of all of its cellular 

 contents except for the connective-tissue stroma, fat cells, blood vessels 



