HISTOLOGICAL CHANGES OF THE CENTRAL NERVOUS 

 SYSTEM PRODUCED BY HELODERMA VENOM. 



By Samuel Leopold. 



The effect of the venom of various snakes upon the cerebro-spinal system 

 has been studied histologically only since 1900. It will not be necessary to 

 review the literature, as this has been done in Noguchi's work on Snake Venoms: 

 An Investigation of Venomous Snakes with Special Reference to the Phenom- 

 ena of their Venoms (Pub. No. Ill, Carnegie Institution of Washington, 

 1909) . It was of interest to compare the action of snake venom with the effect 

 of heloderma venom upon the central nervous system. 



Dr. Leo Loeb kindly placed at my disposal the brains and spinal cords of 

 rabbits and guinea-pigs which had been injected with varying doses of the 

 venom of Heloderma. The inoculations were either given subcutaneously or 

 into the peritoneal cavity. The dose varied from 25 to 60 mg. Some animals 

 were given but one injection, others two, and in one instance four celloidin cap- 

 sules had been introduced intraperitoneally and the poison was allowed to act 

 during a period of 28 days. The animals lived from 5 minutes to several weeks. 

 This material for study was placed in 10 per cent formalin or in Muller's fluid, 

 and the sections were stained usually with thionin (Nissl method) and with 

 hemalum. In one animal (rabbit Bn, living 13 days), sections of the spinal 

 cord were stained by the Marchi method. 



In most cases only the medulla and spinal cord were examined (guinea- 

 pigs 16, 21, 22, 18, A 4 ; rabbit B 2 ). In four cases the cerebral cortex cerebellum, 

 pons, medulla, and spinal cord were studied (rabbits Nos. 1, Bi, and a 8 ). In 

 one instance (guinea-pig a 1 ) sections were taken from every portion of the brain. 



For control a healthy guinea-pig's brain was sectioned at various levels 

 from the frontal lobes to the spinal cord, and stained by the Nissl method. 



The earliest change noted in our animals occurred after 45 minutes (guinea- 

 pig 18). Some of the cells in the anterior horn of the spinal cord took the 

 stain a little more intensely and diffusely. The medulla and spinal cord of 

 several animals dying at shorter intervals than 45 minutes failed to reveal any 

 changes in their cells. Lamb and Hunter found with the venom of Naja defi- 

 nite changes only when the animals lived longer than 2 or 3 hours, but the 

 venom of Enhydrina produced pronounced chromatolytic changes in 90 min- 

 utes, while Kilvington found chromatolysis with the venom of the tiger-snake 

 if the animal survived the injection of the poison for over 3 hours. 



In rabbit No. 1, which lived 75 minutes, some of the ganglion-cells of the 

 spinal cord, medulla, and a few of the Purkinje cells showed an early disinte- 

 gration of the Nissl bodies. A fine powder was seen around the nucleus, which 



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