METHODS 519 



with no deaths. Besides the Institute in Paris, similar institutions exist 

 in other parts of France, in Italy, and especially in Russia, as well as 

 in other parts of the world ; and in these similar success has been 

 experienced. It may be now taken as established, that a very grave 

 responsibility rests on those concerned, if a person bitten by a mad 

 animal is not subjected to the Pasteur treatment. Sometimes during or 

 after treatment there appear slight paralytic symptoms with obstinate 

 constipation and it may he retention of urine, but these pass off within 

 a few weeks and leave behind no ill effects. 



Antirabic Serum, In the early part of the nineteenth century 

 an Italian physician, Valli, showed that immunity against rabies 

 could be conferred by administering through the stomach pro- 

 gressively increasing doses of hydrophobic virus. Following up 

 this observation, Tizzoni and Centanni have attenuated rabic 

 virus by submitting it to peptic digestion, and have immunised 

 animals by injecting gradually increasing strengths of such virus. 

 This method is usually referred to as the Italian method of 

 immunisation. The latter workers showed from this that the 

 serum of animals thus immunised could give rise to passive 

 immunity in other animals ; and further, that if injected into 

 animals from seven to fourteen days after infection with the 

 virus, it prevented the latter from producing its fatal effects, 

 even when symptoms had begun to manifest themselves. They 

 further succeeded in producing in the sheep and the dog an 

 immunity equal to from 1-25,000 to 1-50,000 (vide p. 454), and 

 they recommended the use, in severe cases, of the serum of such 

 animals in addition to the treatment of the patient by the 

 Pasteur method. A like serum has been obtained from animals 

 treated by the ordinary Pasteur method. 



Methods, (a) Diagnosis. When a person is bitten by an 

 animal suspected to be rabid, the latter must under no circum- 

 stances be killed. Much more can be learned by watching it 

 while alive than by post-mortem examination. In the latter case 

 only such things as the occurrence of broken teeth, marked 

 congestion of the fauces, or the presence of unwonted material 

 in the stomach throw any light on the condition ; nothing of a 

 positive nature can be learned from examining the nervous 

 system. On the other hand, in the living animal the develop- 

 ment of the characteristic symptoms can be watched, and death 

 will occur in not more than five days. If the suspected animal 

 has been killed, then a small piece of its medulla or cord must 

 be taken, with all aseptic precautions, rubbed up in a little 

 sterile '75 per cent sodium chloride solution, and injected by 

 means of a syringe beneath the dura mater of a rabbit, the latter 

 having been trephined over the cerebrum by means of the small 



