CAUSES OF NECROSIS 377 



stimulate the action of most enzymes;*'^ autolysis, however, is iiol in- 

 creased (Brown).*" In proper amounts radium stimulates })lant 

 metabolism (Gager). Thorium-a; also attacks specifically the leuco- 

 cytes,*®" so that by proper dosage an animal may be made practically 

 leucocyte-free,''"'' which has been used for experimental studies on the 

 functions of the leucocytes. 



The lonpr-continued action of a:-rays upon the skin has, in many 

 cases, led to the formation of cancer, apparently because the pro- 

 liferation stimulated by the rays progresses until it exceeds normal 

 bounds. ^^ Likewise leukemia has been observed several times in 

 roentgenologists, presumably produced in the same way.**" Radium 

 also causes severe skin lesions and a general lymphocytosis in those 

 exposed to it for long periods.**'' 



As the metabolic changes produced by a'-rays indicate an extremely 

 high rate of autolysis, one may ascribe the effects either to a stimulat- 

 ing effect of x-rays upon autolytic enzymes, or as Neuberg*" does, to 

 an inhibitive action of .r-rays and radium rays upon the other intra- 

 cellular enzymes wnthout a corresponding deleterious effect upon the 

 autolytic enzymes."'" This hypothesis agrees with the facts at hand, 

 but more details concerning the effects of these rays upon various 

 enzymes are needed. The long latent period before the appearance 

 of necrosis after exposure to rr-rays is difficult to explain, and agrees 

 rather wath the hypothesis of slow proliferative and obstructive 

 changes in the blood-vessels. 



Electricity. — The effects of the electric current upon cells are de- 

 scribed by Davenport as follows: A weak constant current causes 

 a centripetal flowing of the protoplasm (in Actinosphaerium) ; if the 

 current is increased or long continued, the cytoplasm of the pseudo- 

 podia becomes varicose, and droplets are formed which soon burst, 

 causing a collapse of the protoplasmic framework. Finally, the pro- 

 toplasm on the anode side begins to disintegrate, and the loose 

 particles move toward the positive electrode; eventually the cell struc- 

 ture may be entirely destroyed. A similar disintegration of the 

 anode side of ameba has been observed by McClendon,^^ which he 



45 Loewenthal, Berl. klin. Woch., 1010 (47), 287: Kionka, Med. Klinik, 1911 

 (7), 685. Denied bv Gudzent, Zeit. Strahlontlier., 1014 (4), 666. 



46 T. R. Brown, Arch. Int. Med., 1012 (10), 405. 



46a See Plesch et al., Zeit. exp. Path., 1012 (12), Xo. 1. 



46b There is no increase in antitrypsin from this leucocyte destruction (Rose- 

 now, Zeit. exp. Med., 1014 (3), 377)". 



47 See review bv Wyss. Beitr. z. klin. Chir.. 1006 (40), 185; Porter and Wol- 

 bach, Jour. Med. Res.', lOW) (21), 357. 



48 See Jagic and Schwarz, Berl. klin. Woch.. 1011 (48), 1220. 

 48a See Ordway, Jour. Anier. Med. Assoc, 1016 (66), 1. 



49 Zeit. f. Krebsforschung, 1004 (2), 171; also Meyer and Berins;, Fortschr. 

 Roentg:enstrahlen, 1011 (17), 33; Richards, Amer. Jour. Physiol., 1014 (36). 400. 



50 Some authors have believed certain of tlie effects of a^-rays to be produced 

 by choline liberated throufrh the decomposition of lecithin. (See Benjamin and 

 Reuss, Miinch. med. Woch.. 1006 (53), 1860.) 



BiPfliiger's Arch., 1011 (140), 271. 



