458 Mr. A. Henfrey on the Reproduction of the 



A curious law presented itself to me in the contemplation of 

 this table ; in each of the three " forms " under which the diflfer- 

 ent conditions of organization are arranged, a multiplication may 

 take place. Now this is effected through a different kind of cell- 

 formation in each ^' form." 



Cells are formed in three ways : — 



1 . By subdivision of an old cell which may become enlarged 

 in one or more directions, or may bud out laterally, before the 

 formation of the septum which divides it into two or more 

 chambers. 



2. By subdivision of the entire contents of the parent-cell 

 into four or more portions, between which septa are usually 

 formed, but which then acquire special coats inside, and by 

 the solution of the parent-cell and the septa become free. 



3. By the formation of a membrane around a small globular 

 mass of contents {nucleus) which has become isolated in the 

 cavity of the cell. 



In the ' Vegetative form,^ the formation of spores and pollen- 

 grains is effected by the second process. [The embryo-sac of 

 Phanerogams is formed by the simple enlargement of a cell or 

 several coalescent cells of the tissue of the nucleus.] 



Tn the * Sexual form,^ the germ-cell of the archegonium, which 

 is impregnated by the spermatozoid, is stated to be formed by 

 the third process^ free cell-formation around a nucleus, and the 

 embryonal vesicle of the Phanerogams certainly originates in 

 this manner. 



In the ' Embryonic form,' the multiplication which takes place 

 in Characese, Mosses, and in the suspensors of Conifers, is 

 effected by cell-division, in the first two cases preceded by bud- 

 ding ; this is the first process, and that which occurs universally 

 in the growth of tissues. 



Recent Literature of the Subject. 



1. Amici. On the Fecundation of the Orchideae. (Memoir read at the Ita- 



lian Scientific Congress, Genoa, 1846.) Abstracted in Annates des So. 

 Nat. 3rd Ser. vii. 193 (1847); and in the Botanische Zeitung, v. 364, 

 1847. 



2. Cruger. Ueber Befmchtung bei den Orangen. Botanische Zeitung ^ 



iv. 57,1851. 



3. Geleznoff. Memoire sur I'Embryogenie du Meleze. Ann. des Sc. 



Nat. 3rd Ser. xiv. 189, 1850. 



4. Henfrey. On the Development of the Ovule in Orchis Morio. Pro- 



ceedings of the Linncean Society of London, April 3, 1849. 



5. Hofmeister. Untersuchung des Vorganges bei der Befruchtung der 



CEnothereen. Botanische Zeitung, v. 785, 1847. Abstracted in Ann. 

 des Sc. Nat. 3rd Ser. ix. 65, 1848. 



6. — . Die Enstehung des Embryo der Phanerogamen : 4to, Leipzig, 



1849. Abstract in Ann. des Sc. Nat. 3rd Ser. xi. 375, 1849. 



