FERTILIZATION 



145 



In 1842 Hartig described an " egg " in the embryo-sac, and 

 claimed that the pollen-tube carries a substance that fertilizes 

 the egg, a view which Schleiden promptly opposed. In the 

 same year Aniici reiterated his previous views and claimed for 

 Orchis and other plants the preexistence in the embryo-sac of 

 a cell which, through the influence of the pollen-tube, becomes 

 the embryo. Schacht opposed this claim, and suggested that 

 such antiquated ideas be abandoned. At the same time, Hugo 

 von Mohl described the egg-apparatus in Orchis Morio, and 

 warmly supported Amici's views. 



In his conclusion Schacht says : " The tendency to error is 

 so bound up in human nature that the work of one's mind, like 

 that of his hand, is never perfect, and consequently I do not 

 consider my work free from error and misconception, but I have 

 tried to minimize these as much as possible. In the chief 



c 



D 



FIG. 66. A, Staphylea ; tip of pollen-tube showing division of generative nucleus. B, 

 Orchis latifolia ; end of pollen-tube showing tube nucleus (in advance) and the 

 two male nuclei. <?, Monotropa Bypopitys\ fusion of sex nuclei, male nucleus 

 more deeply shaded. 7>, the same stage just after fertilization, showing first division 

 of endosperm nucleus, x 450. After SxRASBURGER. 8 



matter, the origin of the embryo from the pollen-tube, no one 

 can convince me that there has been any error or misconcep- 



