M. Tulasne's Researches in Vegetable Embryogeny. 343 



The use of the tube seems to be the preservation of a comnm- 

 nication with the external air when the aperture is closed by the 

 operculum. The following addition to PfeifFer's description of 

 Anaulus will be necessary : — 



" Canali suturali interno profunde in caverna spirse desinente, 

 utrinque pervio/' 



Cheltenham, 13th March 1856. 



XXX. — New Researches in Vegetable Embryogeny. 

 By M. TuLASNE*. 



Dr. Hermann Schacht, a German phytotomist well known by 

 numerous and important works, some months agof allowed 

 himself to be persuaded, that the doctrine of the generation of 

 plants which he has embraced, namely that of M. Schleiden and 

 the pollinists, was then peremptorily established and proved. His 

 belief was founded upon some observations recently made by a 

 young botanist of Berlin, M. T. Deecke, who, as was asserted, 

 by an extremely fortunate dissection of the ovule of the Pedicu- 

 laris sylvatica, had put it beyond a doubt, that the vegetable 

 embryo is actually produced in the extremity of the pollen-tube 

 itself, after the introduction of the latter into the embryonal sac. 

 Two of the botanists most competent to judge of this difficult 

 question, MM. Hugo von Mohl and W. Hofmeister J, have 

 strongly protested against allowing the memoir and anatomical 

 preparations of M. Deecke the demonstrative value which was 

 attributed to them; and although their criticisms have called 

 forth long replies from MM. Schacht and Deecke, supported 

 upon new observations §, there would certainly be cause for 

 astonishment if their confidence in the correctness of their opi- 

 nions had not been somewhat shaken, and their conviction had 

 really remained entire. 



The passage of every creature from non-existence to existence, 

 its entrance into life, is a phsenomenon too mysterious for us to 

 flatter ourselves that we shall ever be able to understand exactly 

 all its circumstances. Nevertheless, as the questions at issue 

 between M. Schleiden and his opponents are questions of fact, 

 antecedent to any doctrinal interpretation, and capable of being 

 judged by our eyes, we need not despair of some day seeing less 

 diversity of opinion amongst the botanists who occupy themselves 



* From the Comptes Rendus, Nov. 12, 1855, p. 790. 



t See the * Flora,' 1855, part 10. 



X See Annales des Sciences Nat. 4 ser. iii. pp. 209 & 219. 



§ * Flora,' 1855, no. 29, and Botanische Zeitung of Berlin, Sept. 14 & 19. 



