52 KEPOET OF THE COilMISSIONER OF AGRICULTURE. 



their having varied in a manner commonly called spontaneous, so that 

 iu either case their sexual elements have in some degree been differen- 

 tiated. And, secondly, that the injury from self-fertilization follows 

 from the want of such diflfereutiation in the sexual elements." Darwin 

 furtber remarks "that the advantages of cross-fertilization depend on 

 tbe sexual elements of the parents having iu some degree become dif- 

 ferentiated by the exjjosure of their progenitors to difiereut conditions, 

 or from their having intercrossed with individuals thus exi>osed, or, 

 lastly, from what we call in our ignorance si)outaueous variation." He, 

 therefore, who wishes to pair closely related animals ought to keep them 

 under conditions as different as possible. Some few breeders, guided 

 by their keen powers of observation, have acted on this principle, and 

 have kept stocks of the same animals at two or more distant and dif- 

 ferently situated farms. This same plan is also unconsciously followed 

 whenever the males, reared in one place, are let out for i)ropagation to 

 breeders in other places. As some kinds of plants sufler much more 

 from self-fertilization than do others, so it jtrobably is with animals 

 from too close interbreeding. The effects of close interbreeding on ani- 

 mals, judging again from plants, would be deterioration in general 

 vigor, including fertility, with no necessary loss of excellence of form ; 

 and this seems to be the usual result. It is, Darwin says, " a common 

 practice with horticulturists to obtain seeds from another place having 

 a very different soil, so as to avoid raising plants for a long succession 

 of generations under the same conditions ; but with all the species 

 which freely intercross by the aid of insects or the wind, it would be 

 an incomparably better plan to obtain seeds of the required variety, 

 which have been raised for some generations under as different conditions 

 as possible and sow them in alternate rows with seeds matured in the 

 old garden. The two stocks would then intercross, with a thorougli 

 blending of th«ir whole organizations and with no loss of purity to 

 the variety, and this would yield far more favorable results than a 

 mere exchange of seeds." 



• Such are the conclusions arrived at by the distinguished scientist re- 

 ferred to. It will be seen that the practice of i)rocuring fresh seeds 

 from foreign countries and remote localities iu our own country", by the 

 Conimissioner of Agriculture, for subsequent distribution, is one which 

 is in full accord with the best attainable light upon this important sub- 

 ject. 



rnoDUCTioN of new varieties of wheat by cross-fecuisda- 



TION. 



The improvement of agricultural plants by cross-fecundation is a sub- 

 ject of the highest importance. It is quite as feasible as the hybridiz- 

 ing or cross breeding in animals. It often involves, however, very 

 extensive inquiry, and when applied to the production of new varieties 

 of wheat, the interests of the farmer, the miller, the baker, and the 

 consumer are all to be duly considered. 



In addition to what has been given on this subject, it maybe stated that 

 in performing the operation it is not only necessary to guard against 

 the lertilization of the ovary from its own anthers, but that it is requi- 

 site that all the other anthers ot the same ear, above the ovaries artifi- 

 cially fertilized, should be extracted; otherwise they would pour out the 

 contents of their pearly globules to the relief of the feathery stigmas 

 and disappoint the experimenter's hopes. For more than ordinary care 

 is taken by nature that the grass tribe, which includes wheat, shall be 



