strikes from its usual S-shaped position, the anterior half of the "body, 

 which is thrown forward, must he free from coil. In striking, the snake 

 simply straightens out the S-shaped curves. It does not have to "be in this 

 position to strike, for observation has shown that when irritated most of 

 our poisonous snnkes ciin strike for short distances from aii.iost any position. 

 The western dianiondback rattler, v/hen excited, frequently raises its head 

 and the S-shaped loop 10 to 15 inches above the ground, from which position 

 it strikes sideward and downvvard. When this rattler is lying coiled with 

 its head resting on its "body, it is a'ble to strike almost vertically up- 

 ward. The greatest length of stroke is about three- fourths the length of 

 the snake, but few snakes strike more thrji half their lengt"ii. 



VEIJOMS 0? POISOLIOUS SMKES - 



"Venom is a secretion of a supralabial gland that resembles in its 

 development the parotid (a salivary) gland in mammals. It is comtposed of 

 50 to 70 percent proteins; the chief remaining components are water and 

 carbohydrates, with occasional admixtures of abraded epithelial cells, or 

 saprophytic micro -orgai^i sins, while salts such as chlorides, phosphates of 

 calcium, magnesium, and ammonram occur in small quantities. The reaction 

 of venom to litmus is iisually acid; in some cases, neutral. The venoms of 

 the different species of poisonous snakes differ to a greater or lesser 

 degree, although all venoms are multiple in nature, that is, they contain 

 several toxins thxa.t act independently of one another. Warm-blooded animals 

 are usually more susceptible to venom, than cold-blooded ones. Dried venom 

 retains its original toxic properties in unaltered strength and quality for 

 an indefinite period. Dr. 3. Weir Mitchell found that venom kept dry for 

 23 years was unaltered in these respects. T/hen fresh, the venom of a snake 

 is a som^ewhat viscid fluid of a yellov/ish color. 



The effect of venom on the victim is due to the complicated action 

 of several toxic elem.ents, of which neurotoxins and hemorrhagins (explained 

 later) are the most important. Neurotoxins have a destructive action upon 

 the nervous system and play the most important part in producing the death 

 of a victim of venom poisoning. They are present in relatively large 

 proportions and are the chief deafn-dealing factors in the venom, of the 

 harlequin snakes ( Micrurus and Micruroides ) , which belong to the cobra 

 family (Elapidae) . In contrast, rattlesnakes ( Cro talus and Sistnarus ) and 

 moccasins (A gkjstrodon) of the family Crotalidae produce neurotoxin in 

 comparatively small quantities. The venom of the cotton-mouth water moccasin 

 contains more neurotoxin than that of the rattlesnake, and consequently its 

 paralytic effect on the respiratory center and miotor nerves is stronger. 

 This toxin not only breaks down the nuclei of the ganglion (nerve center) 

 cells, but produces granular disintegration of the sheath (myelin) and 

 fragm.entation of the conducting portions (axis cylinder) of the nerve fibers. 

 T"nese neurotoxins offer a high resistance to heat and retain their toxic 

 properties after prolonged treatm^ent with alcohol. 



The hemorrhagins constitute t"ne chief toxic elements of rattlesnake 

 venom and have a solvent action on the endothelial cells composing the 

 avails of the blood and lymph vessels, particularly the smallest of them 

 "known as capillaries. One of the most alarming symptoms ensuing from the 

 bite of a pit viper is the enormous swelling and extravasation of blood 



- 7 - 



