NATURE OF VENOMS 153 



occur within a few minutes. AVhen recovery occurs, the disappear- 

 ance of symptoms is remarkably abrupt, within a few hours a des- 

 perately sick person becoming almost entirely free from all evidences 

 of the intoxication. 



Pathological Anatomy. — Postmortem examination shows changes varying with 

 the nature of the poisonous shake that has caused death. In the case of a cohra 

 bite, according to JMartin. the areolar tissue aVmut tlie wound is infiltrated with 

 pinkish fluid; the blood is often lluid; the \eins of the jiia are congested, and 

 the ventricles often contain turbid lluid; the kidneys inay show much congestion. 

 When death occurs in a few minutes, enormous general intravascular clotting is 

 found, which seems to be the cause of death. After death from a viper bite the 

 site of the wound is the seat of intense edema and extravasation of blood; if in 

 the muscles, these are much softened and disorganized. Hemorrliages are fovind 

 in all organs and in the intestinal tract. If death occurs after several days it 

 is generally because of sepsis, and shows the usual changes of this condition ; in 

 addition, as a rule, to marked gangrenous, ulcerative, and sloughing processes at 

 the site of the bite. 



Histologically there are found, in addition to innumerable hemorrhages in nearly 

 all the organs, many vessels plugged with thrombi composed of more or less 

 hemoh'zed, agglutinated erythrocytes. The changes produced in tlie nervous tissue 

 by the Australian tiger snake are described by Kilvington.so ^vho foimd marked 

 chromatolysis, the Nissl bodies breaking into dust-like particles, and eventually 

 all stainable substance disappearing from the cytoplasm; the nucleus retains its 

 central position, but often loses its outline and may disappear. The cells aroimd 

 the central canal of the cord are most affected. There are no inflammatory 

 changes in the nervous system, and if death occurs very quickly there may be no 

 microscopic alterations. Hunter si found similar changes in the Nissl bodies in 

 both krait and cobra poisoning: in the medullated fibers he found the myelin 

 sheath converted into ordinary fat. The venom of sea snakes (Enhijdrina valaka- 

 dien) has a severe action on the nervous tissues, while Daboia has none (Lamb 

 and Hunter 32). Nowak 33 studied experimental animals, and found mucli fatty 

 change in the livers, even if death occurred one-half hour after poisoning; also 

 focal necrosis in the liver, acute parenchymatous alterations in the kidney, and 

 pneumonic patches in the lungs. 



Effects on the Blood. — Tlicre has been much discussion concerning the part 

 played by tlie abvnidant and prominent intravascular clotting in causing death 

 after snake-bite. Lamb s* states that when venoms are slowly absorbed the 

 coagulability of the blood is decreased and it is found fluid after death, but when 

 a fatal dose of venom (viper) is rapidly absorbed, clotting is increased and throm- 

 bosis is the chief cause of death. ]\Iartin has demonstrated very active fibrin 

 ferments in snake venom (loc. cit.). It is highly probable, however, that many 

 of the thrombi of venom poisoning are not produced by coagulation of fibrin, but 

 by agglutination of the red corpuscles, which Flexner 35 has shown can cause 

 large clots in the heart and great vessels, as well as "hyalin" thrombi in the 

 small vessels. 



Nature of Venoms. — The varied effects produced by venoms have 

 been found to' be due to a number of poisonous elements which they 

 contain, and which have been distinguished and separated from one 

 another by Flexner and Nognchi.^'' These are hemotoxins (hemoly- 

 sins and hemagglutinins) , leucocytolysins, neurotoxins, and endothel- 



30 Jour, of Physiol., 1902 (28), 420. 



31 Glasgow Med. -Jour., 1003 (59), 98. 



32 Lancet, 1907 (ii), 1017. 



33 Ann. d. I'Inst. Pasteur, 1898 (12), 369. 



34 Indian Medical Gazette, Dec, 1901. 



35 Univ. of Penn. Med. Bull.. 1902 (15). 324 



36 Jour. Exp. Med., 1903 (9), 257; Univ. Penn. Med. Bull., 1902 (15), 345. 



