102 AMPHIMIXIS, ETC. 



To attain this object it will be necessary first to consider the 

 remarkable morphological processes which accompany the 

 maturation of reproductive cells, and, as far as possible, to seek 

 for a true interpretation in the results of the most recent 

 researches. Furthermore, it will be necessary to apply the 

 ideas thus gained to the problem of conjugation, and to bring 

 within the scope of the enquiry many other phenomena, such 

 as the various kinds of reproduction, certain phases of the 

 question of heredity, and the immortality of unicellular organ- 

 isms, because these are most intimately connected and indeed 

 mutually dependent. 



Thus the thoughts which run through the previous essays 

 resemble tangled threads which are gradually unravelled and 

 are ultimately all woven together. I will only add the wish 

 that the new conceptions to which these researches have led 

 may prove a fruitful field for further investigations. 



AUGUST WEISMANN. 



LiNDAU, Lake of Constance, 

 Septetnber 12, 1891. 



