MISUNDERSTANDINGS : MORE IRRELEVANCIES 185 



mitted that a parent infected with tubercle-bacillus or with the 

 microbe of syphilis may have offspring also infected. But such 

 cases are irrelevant in the discussion. Infection, whether before 

 or after birth, has nothing to do with inheritance. As Dr. Ogilvie 

 says (1901, p. 1072), " Wherever the transmission of infectious 

 disease from parent to offspring has been adduced to support 

 the doctrine of the inheritance of acquired characters, it has 

 been done in utter misconception of its meaning and scope." 



Medical men have sometimes condescended to make a subtle 

 distinction between " hereditary " and " congenital " syphilis — 

 the latter manifested at birth, the former some time afterwards ! 

 It seems strange that they have failed to recognise that there 

 is no reason to use the word " hereditary " at all in this con- 

 nection. What occurs is an injection, and it is theoretically 

 immaterial at what stage the infection occurs.* A microbe 

 cannot be part of an inheritance.f 



Misunderstanding YI — Transmission in unicellulars is not 

 to the point. — It is not to the point to cite cases where uni- 

 cellular organisms, such as bacteria or monads, have been 

 profoundly and heritably modified by artificial culture, so 

 that, for instance, the descendants of a virulent microbe have 

 been made to lose their evil potency. It is irrelevant because in 

 regard to unicellular organisms we cannot draw the distinction 



* It may be the germ-cells'that are infected — especially when the direct 

 source of infection is the father ; or it may be the embryo that is infected 

 through the placenta : but the difference in the time of the infection is of 

 no theoretical interest, nor can it be inferred from any difference in the 

 outward symptoms, as these appear in the offspring. 



f The egg of the green freshwater polyp {Hydra viridis) always contains 

 little greenish corpuscles which are not present in the youngest stages 

 of oogenesis. It is almost certain that these are minute unicellular Algae 

 {Zoochlorellce). But no one can regard these useful symbions as actually 

 part of the inheritance. The eggs of the silk-moth are often infected by 

 a minute but fatal Protozoon which is present in the body of the moth. 

 It seems uncertain at what precise point these pebrine organisms become 

 associated with the egg, but however early it may be, the infection has 

 nothing to do with inheritance. (See Ziegler, 1905, p. 5.) 



