VIPERA BERUS. G9 



water. It produces no change in vegetable blues. When exposed 

 to the open air the watery part gradually evaporates, and a yellowish- 

 brown substance remains, which has the appearance of gum-arabic. 

 In this state it feels viscid between the teeth ; it dissolves readily 

 in water, but not in alcohol ; and alcohol throws it down in a 

 white powder from water. Neither acids nor alkalies have much 

 effect upon it. It does not unite with volatile oils nor the sul- 

 phuret of potass. When heated it does not melt, but swells, and 

 does not inflame till it becomes black. These properties are simi- 

 lar to those of gum, and from the observations of Dr. Russel there 

 is reason to bclive that the poisonous juices of other serpents arc 

 analogous in their properties to those of the Viper. 



The activity of the poison of the Viper depends on a variety of 

 circumstances, but it is most hurtful when mixed with the blood. 

 If the mouth be not excoriated, it may be swallowed in consider- 

 able quantity without causing any serious injury. A pupil of 

 Professor Mangili swallowed the whole poison of four Vipers, and 

 that of six was given to a blackbird with no other effect than that 

 of slight and transcient stupor. Tt appears to be most active in hot 

 climates, in the middle of summer, the period when the animal is 

 most vigorous and active. Its comparative effects upon various ani- 

 mals appear to be regulated by the size of the animal bitten. Small 

 birds and quadrupeds die immediately when they are bitten by a 

 Viper, but to an adult person the bite seldom proves fatal. 



The local symptoms which follow the bite of a Viper, arc an 

 acute pain, in the part wounded, with a swelling, at first red, but 

 afterwards livid, which by degrees spreads rapidly over the neigh- 

 bouring parts, and even affects the viscera, and internal organs. 

 A sanious fluid is sometimes discharged from the wound, around 

 which phlyctense arise, similar to those of a burn. After a short 

 time the pain abates considerably, the inflammatory tendency 

 changes into a doughy, or cedematous softness, the part grows livid, 

 and the skin exhibits large livid spots, like those of grangrene. 

 The general symptoms generally come on within forty minutes 

 after the injury ; the patient is troubled with anxiety, prostration 

 of strength, tendency to fainting, bilious vomiting, diarrhaia, some- 

 times convulsions, quick, small, irregular pulse, difficult breathing, 



