PROF. CREriN : CONttlDERATIOXS OX ''SPFXIES." 



3C5 



of the readers of the Natural tat have 

 in their herbaria two or three speci- 

 mens of pLants from Ihickingham- 

 sliire : if such would forward me the 

 localities of these, they would render 

 me great assistance. If any one can 

 inform me of any work besides those 

 already mentioned, -wherein I may 

 find printed information on the 

 plants of the comity, I shall be 

 equally obliged. I am sure that the 

 plants of the county merit attention : 

 in the neighbourhood of High Wy- 

 combe alone, are such rarities as 

 Dentaria lulhlfera, Daphne Meze- 



rcum, Orchis fusca, and a host of 

 others. ^lay I hope, therefore, that 

 this appeal may not pass unanswered ? 

 " The smallest contributions will be 

 thankfully received" by yours, very 

 tmly, James Britten. — Address 18, 

 Shawheld-street, Chelsea, London, 

 S.W. 



(EKijaitge, 



British Shells. — I shall be glad to 

 exchange Foreign for British, or 

 British for British Shells of various 

 localities. — Wm. Eicn, 14, Great 

 Russell Street, Bloomsbury, London. 



(Drigimtl %xtuhB, 



COXSIDERATIOXS OX "SPECIES'' APROPOS OF A NEW WORK 



BY M. jorda:n^. 



BY FRAN9OIS CREPIN, 



Professor of Botany a "VEcole cV Horticulture,'' Gaud. 



(Continued from j>a/7e 239. J 



Besides he himself informs us : — " In speaking on a succession of fiict? 

 carefully observed by ourselves, we may, by means of a Icf/ifiniate indartion^ 

 arrive at a loell-assured judgment, on the totality of analogous facts which 

 w^e have not been enabled to observe with the same care "(^) 



We must raise against this criterion or against the method of using it 

 an objection of the gravest character. Is it really certain that no variation 

 can survive longer than five, ten, fifteen or twenty j^ears 1 AMiy confine 

 ourselves to so small a number of years ? Is hot such a limitation alto- 

 gether arbitrary'? IVFay it not be that a great number of these fonns 

 remaining stable for five, ten, fifteen or twenty years are really, as the 

 partisans of the old school hold, merely varieties already pretty ancient, — 

 varieties, which dm-ing the lapse of several centuries, have acquired a certain 

 habit, more or less fixed by time? This is a simple .hypothesis, but 



(5) Loo. cit : p. 17. 



