876 THOMAS ORDWAY AND ARTHUR KNUDSON 



morphomiclear to rise during treatment but this tendency was reversed 

 immediately following the removal of the radiations. The remote effects 

 consisted of a fall in the lymphocyte count for two to four weeks after 

 treatment, sometimes lasting until the end of the second month. The fall 

 in the polymorphonuclears was usually less than' the lymphocytes, the lat- 

 ter after from three to nineteen weeks rose to the normal level. When 

 the patient's resistance weakened they found an increase in the polymor- 

 phonuclear leucocytes and decrease in the lymphocytes but without leu- 

 cocytosis due chiefly to an absolute increase in the polymorphonuclear leu- 

 cocytes and usually a decrease in the lymphocytes. Such changes in the 

 blood, however, are subject to considerable fluctuations owing to secondary 

 infections. This is not only true in human beings but particularly ii 

 the experimental study of radiation effects in the blood of animals. 



Woglam and Itami have shown that it is not easy to establish a normal 

 standard for certain laboratory animals, notably mice, that there is great 

 variation in the activity of the hematopoietic tissues in apparently healthy 

 individuals. The age as well as^ intercurrent infections are factors whicl 

 must be taken into consideration. 



Aubertin and Beaujard studying the action of x-rays on the blood 

 and bone marrow show that the marrow is much less sensitive to raying 

 than the lymphoid tissue. They believe that leukopenia may be produced 

 by the x-ray, either by the direct action of the rays upon the leucocytes in 

 the circulation or by its action on hematopoietic tissue which prevents 

 normal regeneration of white blood cells. Brill and Zehner injected a 

 soluble salt of radium (RaCl 2 ) subcutaneously into dogs and rabbits 

 in doses of 0.0025 and 0.093 mgm. and found that almost immediately the 

 number of red cells per cu. mm. was greatly increased. On the day fol- 

 lowing there was another marked increase. This polycythemia persisted 

 for a week and for several weeks the number of red blood cells was con- 

 siderably above normal; the hemoglobin did not rise so markedly. The 

 leucocytes increased rapidly after small injections and in certain instances 

 rose to 200 per cent above the normal. The larger injections on the other 

 hand inhibited leucocyte production. 



Effect on Immunity. X-rays and radioactive substances have such 

 a pronounced effect on the blood and blood forming organs, the bone 

 marrow, spleen, and lymphoid tissue generally that it is not surprising 

 that variations in immunity and susceptibility are produced by exposure to 

 radiations. Hektoen(a) (&) found that long exposure to x-ray at the time 

 the antigens were injected into white rats markedly reduced the production 

 of hemolytic antibodies. He assumed that this was due to the destructive 

 effect on the lymphatic tissues, spleen and bone marrow. In some further 

 experiments he exposed dogs to x-rays for ten minutes, followed the next 

 day by a two and a half minute exposure (approximately ST 1 /^ Kienboeck 

 units) ; they showed slight apparent disturbance of general health and no 



