jo An Examination of Weismannism. 



Either there is such a physiological mechanism as it 

 announces, in which case the relations in question can 

 never be inverted " occasionally," any more than rags 

 may " occasionally " help to construct the mill which 

 is to form them into paper ; — or else there is no such 

 mechanism, in which case we may have to do with 

 gemmules. physiological units, stirp, micellae, pangenes, 

 plastidules, or any of the other hypothetical " carriers 

 of heredity " to which our predilections may happen 

 to incline ; but the one substance with which we 

 certainly have not to do is germ-plasm 1 . 



After these tedious but necessary preambles, we 

 may now proceed to examine Professor Weismann's 

 postulate as to the perpetual continuity of germ-plasm, 

 with its superstructure in his theory of heredity — 

 reserving for the next chapter our examination of his 

 further postulate touching the absolute stability of 

 germ-plasm, with its superstructure in his theory of 

 evolution. 



The evidence which Weismann has presented in 

 favour of his fundamental postulate of the perpetual 

 continuity of germ-plasm may be conveniently dealt 



1 On previous occasions, when inconsistencies have been brought to 

 the notice of Professor Weismann by his critics, he has complained that 

 sufficient allowance was not made for the fact of his having published 

 his sundry essays at different times. This, of course, is a satisfactory 

 answer in cases where criticism refers to a growing theory, the later 

 additions to which supersede certain parts of the earlier construction. 

 But clearlv the answer is not available in cases where one set of 

 statements, touching fundamental principles of the theory, are directly 

 opposed to others. A logical contradiction is not affected by dates 

 of publication, and where the contradictory statements have reference 

 to the vital essence of a theory, it is equally impossible for the theory 

 to comprise them whether they be presented simultaneously or sue- 

 ccssivdy. 



