34 



tlio polleu tube. The correctness of tliis view was coutirmed the followiug 

 year bj' von Mohl aud Hofuieister, the hitter of whom described the points 

 in detail wiiicli decided the question, and illustrated tlieni with beautltul 

 figures. 



FolluwiuL? the )»ublication of Aniici, a vehi'uient controversy arose be- 

 tween the adberents of the views ot Schleiden aud those uf Amici. A prize 

 ottered by tlie Institute of tlie Xetlierlauds at Amsterdam was awarded to 

 an essay by Scliaclit in 1850, wliich defended Schleidens theory, and illus- 

 trated it by a numl)er of drawhigs giving both incorrect and inconceivable 

 representations of the decisive points. In this case the prize essay was re- 

 futed before it appeared, by von Mohl, Hofmeister and Tulasue. Von Mohl's 

 words uttered in ]M>3 in regartl to the value of prize essays are so fitting 

 at the present day that I can uot refrain front quoting. He said : "Now 

 that we know that Schleiden"s doctrine was an illusion, it is instructive, 

 but at the same time sad, to see how ready men were to accept the false 

 for the true; some, renouncing all ob.servation of their own, dressed up 

 the phantom in theoretical principles; others with the microscope in hand, 

 but led astray by their j irecouceptious, believed that they saw what they 

 could not have seen, and endeavored to exhibit the correctness of Schlei- 

 den"s notions as raised above all doubt by the aid of hundreds of figures, 

 which had everything but truth to recommend them; and how an academy 

 by rewarding such work gave fresh confirmation to an experience which 

 had been re])eated]y made good especially in our own subject during manj- 

 years past, namely, that prize essays are little adapted to contribute to 

 the solution of a doubtful question in science." 



The discovery of the sexual process in crypttjgams by Thuret, Priugs- 

 heim and others followed within four or five years after the complete 

 establislnneiit of that process in the higher plants. It seems strange to 

 us now that a phenomenon so easy of observation was jiot discovered un- 

 til its occui-rence had been cojupletely demonstrated in organisms present- 

 ing the greatest dilhculties to its investigation. However, it is of inter- 

 est to recall that just thirty-two years ago Strasburger traced the essen- 

 tial constituents of the nucleus in unbroken sequence from one cell genera- 

 tion TO another, thus establishing for the nucleus the rank of niori)liologi- 

 cal unity; and just thirty-two years ago also Oscar Ilertwig showed that 

 fertilization consists essentially in the union of the two gamete nuclei. 

 It only remained now for later studies on the cell to confirm and to estab- 

 lish the doctrine that the nucleus is the bearer of the heredity characters. 



