48 ANAPHYLAXIS AND ANTI-ANAPHYLAXIS 



At the Pasteur Institute therapeutic sera are 

 heated to 56° C. four da3^s in succession, for an hour 

 each time. In the first place, raising the tempera- 

 ture in this way prevents the possible risk of con- 

 tamination, but without doubt this practice also 

 renders the sera considerably less toxic. This ex- 

 plains why in France serum accidents have always 

 been relatively rare, and why in the small number of 

 cases (13 per cent.) in which they occur they are not 

 of such a serious nature as they are in countries 

 where sera are not heated. 



We ought, however, to recognise the fact that the 

 heating of serum is only a last resource ; it is a palli- 

 ative — valuable, it is true, but very inadequate in 

 certain cases. 



The ideal would be to find a means of not only 

 rendering possible the mitigation of serum accidents, 

 but of avoiding them and preventing them. With 

 that aim in view it would be necessary to be able to 

 act, not on the sera by heating them, but on the 

 animal itself, by rendering it impervious or insensitive 

 to the test injection. 



As our experiments have shown, this immunity of 

 the animal to reinjection can easily be realised, and 

 may be of either a transitory or durable nature. Let 

 us examine two cases. 



If it be true that serum sickness is a reaction of 

 the nerve centres, as we stated the hypothesis at the 

 outset, we believe, in company with M. Roux, 

 that we ought to be able to suppress the anaphylactic 

 shock by lowering the nervous sensibility of the animal. 



Experience has shown us, indeed, that when the 

 sensitised guinea-pig is anaesthetised with ether, and 

 that when, during the narcosis, 0-25 c.c. of serum — 

 a maximum dose, undoubtedly lethal — is injected 

 into the guinea-pig intracerebrally, no reaction is 

 observed: the animal awakens sound and unhurt. 



