34 



the poileu tube. The correctness of this view was coufirmed the following 

 year by von Mohl and Hotiueister, the latter of whom described the points 

 in detail whidi decided the questiou. and illustrated them with beautiful 

 figures. 



Following the publication of Amici, a vehement controversy arose be- 

 tween the adli.erents of tlie views ot Scldeiden and tliose of Amici. A prize 

 otiered by the Institute of tlie Netlierlands at Amsterdam was awarded to 

 an essay by Schacht in 185U, wliich defended Schleideu's tlieory, and illus- 

 trated it by a number of drawings giving both incorrect and inconceivable 

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

 futed before it appeared, by von Molil, Hofmeister and Tulasue. Von Mohfs 

 words uttered in 1863 in regard to the value of prize essays are so fitting 

 at the present day that I can not refrain from quoting, lie said : "Now 

 that we know that Schleideii"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 observation of their own, dressed up 

 the i)hantom in theoretical principles ; others with the microscope in hand, 

 but Jed astray by their preconceptions, believed that they saw what they 

 could not have seen, and endeavored to exliibit 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 ri'warding sucli work ga\'e fresh confirmation to an experience which 

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

 years i)ast. 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 cryptogams by Thuret, Prings- 

 lieim and otliers followed witliin four or hve years after the comi)lete 

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

 us now that a ])henonienon so easy of observation was not discovered un- 

 til its occuj-rence had been cojni)letely demonstrated in organisms present- 

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

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

 tial constituents of tlie nucleus in unbroken secpience from one cell genera- 

 tion lo another, tiius establishing for the nucleus the rank of morphologi- 

 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 conlirm and to estab- 

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



