of the Spores in Spirogyra. 211 



"Nevertheless" — he says there* — "it is more than probable 

 that the observations made by Vaucher were not characterized 

 by that great accuracy which is needful here, since, as the figui-es 

 given show, the growth of these young Confervse is in contradic- 

 tion to all analogy, and it is therefore very necessary to repeat 

 these invest! gations.'^ But he must have been subsequently 

 convinced by his own observations of the correctness of Vau- 

 cher's statements, for in his ' Manual of Physiology t,' he gave a 

 description of the germination, which, while devoid indeed, as the 

 limits of a manual compel, of that requisite detail which con- 

 stitutes the value of a monograph, represents all the essential 

 points of the phsenomena so truly, that I have only to confirm 

 all that he states of it in this place. 



The third confirmation comes from Alex. Braun, in his recent 

 work, *^ Observations on the Phsenomena of Rejuvenescence in Na- 

 ture j.' He mentions here, in several places§,not only the changes 

 of the contents of the spores preceding germination, but the 

 phsenomena of the commencement of germination, the dehiscence 

 and the stripping ofi^ of the spore coats. 



Opposed in appearance to these exact observations on the ger- 

 mination of the bodies originating in the conjugated cells of 

 Spirogyra, stands the statement of Agardh ||, that these bodies 

 are broken up into moving spores after a certain time ; on which 

 account Hassall^, who participates in this view, considers these 

 bodies, not as spores, but, as the sporangia of the Spirogyra. 

 Unfortunately, the short account of Agardh, which, although 

 the subject well deserved it, was not accompanied by drawings, 

 does not allow of satisfactory conclusions as to the phsenomena 

 observed by him. Meyen** had already noticed that secondary 

 — but not moving — cells were often formed inside the spores of 

 Spirogyra, and he conjectured that there were likewise propaga- 

 tive cells. I have also found these secondaiy cells, in which 



* Linnaea, 1827, p. 421. f Pflanzen-Physiologie, iii. 422-424. 



X Beobachtung iib. die Erscheinungen der Verjiingung in der Natur. 



§ Loc. cit. pp. 144, 192, 21.^^, 216. 



II The passage runs (Ann. des Sc. Nat. 2nd Ser. vi. 197) : "After many 

 vain attempts to see the elliptical body developed into a new filament, as 

 described by Vaucher, I saw it, on the contrary, broken up definitively into 

 numerous sporules endowed with a rapid motion." 



H History of British Freshwater Algae, p. 130. 



** " In fig. 13. pi. 10. are represented similar seeds (Samen) of Spirogyra 

 princeps, which have been formed without conjugation^ and this is very 

 general in Spirogyra quinina ; they also exhibit double coats ; but the mass 

 in their interior has been transformed into small vesicles, which probably 

 may likewise be spores, the further behaviour of which, however, I have not 

 seen. But the formation of these little vesicles in the true seed is not 

 always to be met with in these unconjugated Confervas, and usually the 

 green mass is spirally arranged here also." — Meyen, loc. cit. 



14* 



