Fecundatiun uf the Ovum. 307 



analogy, \vc cannot help regarding this as a reason for paying 

 more attention to an opinion which is held by such distinguished 

 observers as Schleiden, Schacht, Pringsheim, &c.* 



We have thought it necessary to dwell briefly upon the fecun- 

 dation of the vegetable ovule to complete what we had to say of 

 the fecundation of the animal ovum ; for it must be confessed, 

 the relations are here so considerable, that they approach what 

 we are accustomed to regard as serial identity in the study of 

 organized beings. The distance which separates the modes of 

 generation in different animals from one another, is often much 

 greater than that which separates the mode of generation of a 

 particular aninuxl from that of a i)articular plant. AMiy then 

 separate what Nature has united ? Why wish to follow Schleiden 

 when he refuses to recognize any relation between the physio- 

 logical phamomena presented by plants and those of animals 

 (without saying icliy, however !) ? Every day the precise limits 

 which have been arbitrarily drawn between the vegetable and 

 animal kingdoms are disappearing from our view, — the physical 

 and chemical characters have fallen one after the otherf, and we 

 have been compelled to fall back upon the presence of vibratile 

 cilia and a contractile vesicle, which animals alone ought pro- 

 perly to possess. The first of these characters is already inad- 

 missible, on account of the zoospores of a great many Algaj; 

 and if we choose to consider the motive organs of these as 

 bristles rather than as vibratile cilia, the Closteria w ill always re- 

 main as a stumbling-block. These, although generally regarded 

 as plants, and having nothing animal about them, arc, in fact, 

 clothed with vibratile cilia on the whole of their internal surface. 

 These cilia, first discovered by FockeJ, but afterwards disputed 

 by many, do really exist. If we take the contractility of the 

 cell as the test, we must raise to the rank of animals the Monads, 

 Cryptomonads, Chlamidomonads, and all the Monadina in 

 general, as they have always one or two contractile vesicles. 

 The botanists must also cease to regard the Euglence as plants, 



* [Henfrey (Ann. Nat. Hist. 2nd Ser. xv. p. 349 ; Microscoi)ic Dic- 

 tionarj', article Ovui.e ; and in a paper recently laid before the Linuaean 

 Society of Loudon) holds that the fluid of the pollen-tube fecundates a 

 protoplasmic corpuscle pre-existing in the embryo-sac, and determines the 

 formation of a membranous coat converting this into the germ- or embn,o- 

 cell. — Ed. Ann. Nat. Hist.'] 



t The presence of amyhiccous substances has entirely lost its import- 

 ance since they have been found, not only in the Tunicata, but also in Man 

 himself. Yirchow (Wurzburger Vcrhandlungen, 1851 ; Annals, ser. 2, 

 vol. xiii., p. 158), Prokitanski and Luschka (Virchow's Archiv, 1853), have 

 demonstrated the presence of cellulose in the human brain {corpora amylacea 

 of Purkinje), in the Mali)ighian follicles, in the spleen, in bones attacked 

 by softening, &c. 



X Physiologische Studien. Bremen, 1847. 



