Immunity acquired hy natural means 451 



jtween the agglutinative, antitoxic, and protective properties, to 

 ^certain whether the ingestion of agglutinative milk can confer any 

 rglutinative property on the blood serum. Numerous researches in 

 lis direction were carried out in connection with typhoid fever. 

 Idal and Sicard {I. c.) caused a person to drink daily (for a period of 

 iree weeks) half a litre of milk coming from an immunised goat, a 

 lilk which powerfully agglutinated the typhoid coccobacillus. The 

 )lood, examined on several occasions, never showed the slightest 

 jglutinative power. This experiment goes to prove that, in the 

 idult human subject, the agglutinin does not pass from the ali- 

 lentary canal into the circulation. May it not perhaps be otherwise 

 infants which are fed on milk only ? An observation by Landouzy 

 ^and Griffon^ seemed to confirm this supposition. They first demon- 

 strated the agglutinative power of the blood serum in a woman who 

 had contracted typhoid fever three months after her lying-in. Being [473] 

 a mild attack the woman continued to suckle her child during the 

 whole course of the fever. On examination of the blood of the infant 

 it was found that the serum agglutinated the micro-organism of 

 typhoid fever. These observers did not measure the agglutinative 

 power of the blood, either in the infant or in the mother. Tliis 

 omission deprives their observation of value since it is now recognised 

 that normal human blood fairly frequently exhibits some power of 

 agglutinating the typhoid coccobacillus. For diagnostic purposes it 

 is necessary, therefore, always to measure this power in order to be 

 sure that it is higher than that of the normal blood. 



It is all the more difficult to draw any positive conclusion from 

 the observations of Landouzy and Grifibn because in several similar 

 cases the result has been entirely difierent. Thus Achard and 

 Bensaude^ have shown that the blood of an infant, suckled by a 

 nurse attacked by typhoid fever and whose serum became distinctly 

 agglutinative, was incapable of bringing about clumping of the 

 typhoid coccobacilli. Schumacher^, working in Fraenkel's laboratory 

 in Halle, studied a case with very great care. A woman gave birth 

 at full term to an infant whose blood serum exhibited a certain 

 agglutinative power. The mother suckled the infant from its birth. 

 Although her milk manifested a very considerable agglutinative 

 property, the blood of the child exhibited not only no increase in 



1 Compt rend. Soc. de biol, Paris, 1897, p. 950. 



2 Semaine med., Paris, 1896, p. 303. 



3 Ztschr.f. Hyg., Leipzig, 1901, Bd. xxxvir, S. 323. 



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