METHODS 621 



body in order to enable it to cope with a local pathological 

 change, the locus in this case being the nervous system. We 

 are thus unable at present to give a rational explanation of the 

 efficacy of the treatment, but again attention may be directed to 

 the bearing which the development of hypersensitiveness may 

 have to the occurrence of the phenomena of infective disease, 

 and Harvey and McKendrick draw attention to the fact that 

 some of the concurrent symptoms associated with the treatment 

 closely resemble anaphylactic phenomena. 



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. 562), 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. (1) Diagnosis. The work on the specificity of 

 the Negri bodies for rabies has led to a modification in the 

 procedure to be adopted. Formerly it was advisable if possible 

 to keep an animal suspected of rabies alive for the observation 

 of symptoms. While the clinical history of the animal ought 

 to be carefully obtained, greater information will be obtained 

 by examination of its hippocampus. The animal should there- 

 fore be killed and the brain removed after reflecting the scalp 

 and cutting through the calvarium with a sharp chisel. The 

 brain is laid down, vertex uppermost, and the upper parts of one 

 hemisphere are removed in thin horizontal slices till the anterior 

 part of the lateral ventricle is reached. The roof of the ventricle 

 is then cut away with a probe-pointed bistoury, and the 

 hippocampus will be recognised as the laterally arched ridge 

 which forms the floor of the ventricle. This may be transversely 



