504 THE SNAKES OF SOUTH AFRICA. 



with the liquid (serum) part of the blood, and acts as a poison to 

 disease genus. The injection of increasingly large doses of snake 

 venoms into a horse act in a similar manner, only to a far more 

 powerful degree. We can, within two years, make a horse 

 immune to a hundred times an ordinary fatal dose of venom. 

 The potent venom-killing essence is all in the scrum of the horse's 

 blood. This is why we use the senim. Serum and vaccine are, 

 therefore, totally different. 



People who have been inoculated at various times with 

 vaccine do not suffer from anaphylaxis or serum sickness if a 

 dose of serum is injected into them for the first time. 



H. 



Intravenous versus Subcutaneous Injection of Serum. 



It must be borne in mind that serum injected intravenously 

 (direct into a vein) is on an average fifty times greater in its 

 curative effects than if injected subcutaneousl}^ (under the skin). 

 This is highly important to remember in the treatment of snake 

 venom poisoning, for the reason that if the scrum comes in 

 contact with the venom while it is yet in the blood, it will render 

 it harmless in proportion, of course, to the quantity and quality 

 of the anti-venene seiTim used. In the case of the Cobras, the 

 venom, after a time, leaves the blood and enters into combination 

 with the nerve cells, notably those composing the nerve centres 

 controlling the movements of the lungs. In the viper (adder) 

 family of snakes, including the Boomslang, which is a Colubrine 

 snake, the venom seriously affects the walls of the capillary blood 

 vessels, causing such changes in the cells as to allow the blood 

 to flow out into the various tissues. Now, it is obvious that if 

 the venom has, previous to the injection of the serum, acted upon 

 nerve cells, and the cells of the blood vessel walls, the serum 

 cannot repair the damage done. All it is capable of doing is to 

 neutralize whatever venom remains in the circulation, and so 

 prevent further mischief. Then, if the damage is not beyond 

 repair, the inherent curative power of the body will build up new 

 cells, absorb and cast out the dead blood, and restore the body 

 to its normal condition. A good all-round plan is to have at 

 least enough anti-venene serurft on hand for two full treatments, 

 viz. about fifty cubic centimetres. Then if any one is bitten, 

 inject one full dose of say twenty-five cubic centimetres in two 



