VACCINATING INJECTION 49 



The same thing happens when the guinea-pig is 

 rendered insensible with alcohol. Take, for instance, a 

 sensitised guinea-pig and make it imbibe alcohol, or, 

 better still, administer alcohol by rectal lavage. 

 Then let it sleep off the effects of the alcohol for an 

 hour or two, until it returns by degrees to its nearly 

 normal condition. At this moment inject into it one 

 lethal dose of serum intracerebrally. The animal will 

 not react, any more than will a fresh guinea-pig; 

 that is to say, it will not manifest the slightest 

 anaphylactic symptom. This experiment shews, 

 therefore, that in lowering the sensibility of the 

 animal by alcohol, the sensitised guinea-pig is un- 

 affected by the lethal injection of serum. This 

 immunity lasts, at least, for twenty-four hours 

 following the absorption of the alcohol. 



Besides ether and alcohol, other anaesthetics have 

 been tried. Ethyl chloride gave us the best results; 

 but it is not equal to ether, and still less to alcohol, 

 because the manipulation of it is difficult. Ethyl 

 chloride anaesthetises the guinea-pig with extreme 

 rapidity, but it is also eliminated from the organism 

 very rapidly. This is both an advantage and at the 

 same time a disadvantage. We onty succeed in main- 

 taining the narcosis by an almost uninterrupted 

 administration of the drug; the guinea-pig must be 

 watched very nearly all the time, and it is necessary 

 to make it breathe the ethyl chloride diluted with 

 air. With urethane and chloralose the animal will 

 survive several hours (as many as sixteen hours); 

 we have not, however, succeeded in obtaining com- 

 plete recovery with these substances. Banhoff 

 obtains good results with chloral hydrate. 



On the contrary, morphine hydrochloride and 

 extract of opium have given us definitely negative 

 results. These substances leave the hypersensibility 

 of guinea-pigs completely intact, and the animals 



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