

267 



i 



a case quite analogous to that of sodium-chlorate in so far, as it 

 can racily be obtained in enantiomorphous crystals of monoclinic 

 symmetry, both of which however give absolutely inactive so- 

 lutions. The crystal-forms are reproduced in fig. ijo a and b; 

 they have the symmetry of the group C z . 



Just as in the case of sodium-chlorate, it was here also noticed 

 that when a few large crystals separated from the solution, these 

 Were nearly always of the same kind, whereas a large crop of 

 small crystals generally consisted of both forms in about equal 

 numbers. 



Now in the case considered there is indeed every probability 

 that to the enantiomorphism of the crystal-forms, corresponds a 

 real enantiomorphism of the atomic arrangement in the constituent 



Fig. 170. 



Ethyl-propyl-piperidonium-iodide. 



molecules : for we have here evidently to deal with a derivative of 

 a pentavalent, asymmetric nitrogen-atom which, as we have seen, 

 can in many cases exhibit a true molecular dissymmetry (p. 233). 

 There is every probability here that the explanation suggested 

 above is valid in this case, and the great analogy of this 

 behaviour with that of the sodium-chlorate-crystals could easily 

 persuade us to adopt in the last case also a similar inter- 

 pretation of the phenomenon, as might be given for the piperi- 

 ^ora'ww-derivative. 



In any case it seems worth while to keep these facts in mind, 

 and to gather more instances before rejecting completely the 

 ideas discussed above. 



30. If we review once more what the considerations dealt 

 with in this chapter have led to, we may say that the meaning 

 of Pasteur's famous law has become appreciably clearer after 



