452 Chapter XIV . 



agglutinative power but a marked diminution. The agglutinin of the 

 maternal blood had not passed into the fluids of the child. 



From the point of view of the impossibility of acquiring immunity 

 by suckling, therefore, the human subject may be grouped with the 

 guinea-pig, rabbit and cat. Up to the present the mouse is the only 

 exception. It would be very important, with the object of finding a 

 means of communicating immunity by way of the intestine, to study 

 the precise conditions which govern this phenomenon. In hereditary 

 immunity, or rather in what appears to be such, those cases where 

 the new-born animal exhibits a resisting power induced by the 

 vaccination to which it has been subjected in the womb of the mother 

 must be borne in mind. We have already cited the example given 

 by Remlinger of rabbits and guinea-pigs born refractory against the 

 typhoid coccobacillus, which had been injected into the mother 

 [474] animals. In those cases where the vaccination of the mothers has 

 been carried out during the period of gestation the immunity of the 

 young ones is more permanent than when it was completed before 

 that period. Into this same group come those cases where women, 

 vaccinated during the course of pregnancy, give birth to infants 

 refractory to vaccine. Similar facts have been reported by veterinary 

 surgeons with regard to sheep-pox ; Arloing, Cornevin, and Thomas^ 

 have offered similar demonstrations with regard to symptomatic 

 anthrax. 



These results may be more or less closely associated with those 

 where the child attacked by an infective disease immunises the 

 mother. Such facts are rare. We know that a healthy mother may 

 give birth to a syphilitic child ; the affected father introducing the 

 virus with the sperm, the contaminated foetus contracts the disease 

 and the new-born infant is syphilitic. According to Ehrlich and 

 Hubener (I c. p. 54), the foetus instead of infecting the mother sets 

 up in her a refractory condition. It must be confessed that as yet we 

 do not understand the mechanism of this immunity ; but in any case 

 we have here to do with an example of immunity naturally acquired 

 under very special conditions. 



Here again must be recognised another form of immunisation : — 

 where the child born of a syphilitic mother remains healthy and 

 contracts syphilis neither by the breast nor through the kisses of the 

 mother. Here, undoubtedly, we have an immunity against syphilis 

 acquired in the womb of the mother, who may, however, readily com- 

 ^ " Le charbon bacterien," Pai-is, 18&3, p. 184. 



