384 THE GERM-PLASM 



As such eminent botanists as Focke,* and more recently de 

 Vries,t have expressed much doubt with regard to these obser- 

 vations — or rather interpretations, — we must wait until these 

 cases have been critically reinvestigated before attempting to 

 account for them theoretically. The chief difficulty we should 

 meet with in any such explanation would be due to the fact that 

 we are here concerned with the influence of the germ-plasm of 

 the sperm-cell on a tissue of another plant which only con- 

 stitutes a pai't of this plant. It would thus be necessary to 

 assume that all the determinants of this germ-plasm are not 

 active, and that only those take effect which determine the 

 nature of the fruit. 



The uncertainty of the observations is still greater in the in- 

 stances of so-called infection of the germ. If the case recorded by 

 Darwin — but not observed by him personally — is reliable, and 

 has been accurately described, all doubts must be set aside. A 

 mare belonging to Lord Morton ' bore a hybrid to a quagga,' 

 and subsequently ' produced two colts by a black Arabian horse ; 

 these colts were partially dun-coloured, and were striped on 

 the legs more plainly than the real hybrid, or even than the 

 quagga. One of the two colts had its neck and some other 

 parts of the body plainly marked with stripes,' and the hair of 

 the mane is said to have resembled the short, stiff and upright 

 mane of the quagga, instead of that of the horse. J Similar cases 

 of the influence of a previous fertiUsation on the structure of 

 subsequent offspring are related of several domestic animals, — 

 viz., of cows, sheep, pigs, dogs, and pigeons, as well as of human 

 beings when crosses occur between white races and negroes. 



Up to the present time no experiments have been made with 

 this special object, and it would be necessary to use every con- 

 ceivable precaution in conducting such experiments, or they 

 would be valueless ; they could, therefore, be best made in 

 zoological gardens, not only because of the undoubtedly pure 

 material which might be used for the purpose, but also because 



* Focke, ' Die Pflanzen-Mischlinge,' Berlin, 1881, p. 510, et seq. 



t Hugo de Vries, ' Intracellulare Pangenesis,' Jena, 1889, p. 206. 



\ I have quoted this case from Darwin's ' Variation of Animals and 

 Plants under Domestication,' 2nd ed., Vol. I., p. 435. Darwin does not 

 seem to have known of the drawings of these colts which will be mentioned 

 in a subsequent paragraph. I have not seen them, and only learnt of 

 their existence from Settegast's book. 



