ACQUIRED IMMUNITY 131 



more and more capable of producing the digestive substances 

 which attenuate and destroy the toxins ; and, therefore, up to 

 the time of her recovery, she becomes more and more capable 

 of conferring immunity on her offspring ; for, as time lapses, 

 there pass from her to the child toxins in a greater and 

 greater state of attenuation. Then, if the child be infected 

 (as usually occurs), the digestive substances he receives 

 through the placenta tend to destroy the micro-organisms 

 and attenuate the toxins produced in him. At length, before 

 recovery and immunity are achieved, a time arrives, the 

 advent of which varies in different individuals, when the 

 digestive substances produced in the infected mother are of 

 such potency or in such abundance that the toxins are so 

 much attenuated as not to destroy the child, who is then 

 born alive, and it may be of a fat and healthy appearance. 1 

 In him are present digestive substances, and the micro- 

 organisms of the disease. Frequently in such a child the 

 disease reasserts itself after birth ; the child begins to pine 

 and ere long perishes. The only possible explanation of this 

 phenomena appears to be the following : the digestive bodies 

 from the mother attenuate the toxins sufficiently to protect 

 the child from injury while he remains in the uterus, but 

 not sufficient to bring about in the young individual a pro- 

 tective reaction. Therefore after birth, when the digestive 

 bodies derived from the mother are exhausted, the toxins 

 produced by the parasites within the child, and not now 

 altered, cause his death. But at a still later stage in the 

 mother's disease the toxins are so much attenuated that the 

 cells of the child are able to react, and, therefore, though 

 after birth the signs of the disease may be seen, he recovers 

 and is afterwards immune. Still later, when the mother has 

 recovered, when her cells have acquired the power of resisting 

 the toxins and she is immune, the child can acquire from her 

 neither the disease nor the immunity, since the toxins, attenu- 

 ated or otherwise, no longer pass from one to the other. 2 



1 Be it remembered that here we speak in general terms only. As is 

 well known living children may be born to a mother during all stages 

 of her disease ; but abortions and miscarriages are most frequent during 

 the earlier stages, and of such children as are born alive the great 

 majority perish. It is very significant, moreover, that hand-fed syphil- 

 itic children are more liable than those who are breast-fed to marasmus. 

 (Coutts.) It is known that antitoxins are secreted in the milk, and 

 Ehrlich believes that the " congenital" transmission of acquired immunity 

 is due in part at least to the presence of large quantities of antitoxins in 

 the milk. 



2 We cannot set forth positive evidence proving that the children born 

 of a mother recovered from syphilis and immune to it are not themselves 



