412 THE SNAKES OF SOUTH AFRICA. 



been punctured, remove the ligature, fill the syringe and inject 

 the serum. 



Inject the serum slowly but forcibly. Here I would 

 warn the operator to see that no air-bubbles or particles of solid 

 sediment are injected into the blood, as they might cause serious 

 mischief, and even death. It is safest to strain the serum if it 

 is to be injected direct into a vein. Draining it through butter 

 muslin will do. Remember the syringe should be completely 

 filled with serum so as to allow no space for air. Do not inject 

 the whole of it. Leave a little in the syringe. This will prevent 

 any chance of air-bubbles being injected. It is well to put a 

 piece of butter muslin in the box with the serum so as to be 

 ready for use.* 



In drawing up the serum into the syringe, pull the piston rod 

 slowly. Do not jerk it up rapidly, because air is likely to get in. 

 Sometimes the knob of the piston rod does not fit the barrel 

 sufficiently tightly to cause a full charge to be sucked up. But 

 it usually gets tight enough when a little serum is taken up, as 

 the fluid causes it to expand. The syringe which I have designed 

 for the purpose is made in such a way that it cannot possibly go 

 wrong. Ordinary syringes cannot be relied on. 



Of course, the syringe and needle must be scrupulously clean. 



Sometimes a kind of nettle rash appears where the serum has 

 been injected, but this need cause no alarm. It will disappear 

 in a day or two. 



If the serum be injected direct into a vein in sufficient quantity 



before any symptoms of poisoning have set in, it will neutralize 



the poison and no poisonous symptoms will appear. If very 



alarming symptoms of poisoning have set in, such as extensive 



swelling, subcutaneous haemorrhage, nausea, clammy skin, or 



coma before the injection of serum, then it is advisable to use a 



double dose. In a case which came under my observation where 



the man was in a state of insensibility and sinking fast, 50 c.c. of 



serum were required to save his life. 100 c.c. is the largest dosage 



I have known to be given. Provided sufficient serum has been 



injected, and if the patient's nervous system is not paralysed, 



or his blood damaged beyond recovery, then he should begin 



slowly to mend. From hour to hour he will improve, until 



* Hold the syringe with needle upwards. Then b}' gently pushing the 

 piston until the liquid oozes out, any air there may be in the barrel will be 

 driven out. 



