Miscellaneous. 171 



sesses them together. He insists repeatedly upon this character, 

 especially at pp. 37, 47, and 51 of the work ahove cited. It is on 

 account of the simultaneous existence of these three organs, ascer- 

 tained by all observers, and particularly by F. Cohn, in tho Volvo- 

 cinea3, that Stein has oxcluded them from the vegetablo kingdom, 

 and placed them among the Flagellate Infusoria. We shall find 

 that this character is of no importance, and that it occurs in Algce, 

 upon the vegetablo naturo of which Stein himself would not venture 

 to cast a doubt. 



In the first place, it is useless to dwell upon vibratilo cilia ; every 

 one knows that all zoospores aro furnished with them. 



I pass to the contractile vacuole. And here I cannot refrain from 

 expressing my astonishment to see a naturalist so exact, and gene- 

 rally so well informed, as Stein still denying the existence of this 

 organ (p. 47) in well-characterized plants. It has been seen by 

 Leitgcb, De Bary, Fresenius, Strasburger, Dodel-Port, and Cien- 

 kuwski in the zoospores of Saprolegniese, of Cystojms, of Myxomy- 

 cetes, of ralmellacese, of Ulothrix, of Ifydmrus, of Chtdophora , &c. ; 

 I have myself indicated it in Microspore*, Jloccosa and Stigeoclonium 

 tenue ; and I am convinced that it will be found in many other zoo- 

 spores if it is sought with high magnifying-powers and under good 

 conditions of observation. At any rate, the numerous facts already 

 ascertained are sufficient to refute the assertion of the celebrated 

 professor of Prague. 



There remains the nucleus ; and Stein, in denying its existence in 

 tho zoospores of the Algse, is in accord with eve^body. All the ob- 

 servers who, since Thuret, have studied these organisms have been un- 

 able to discover a nucleus in them ; and Strasburger, quite recently 

 (' Botan. Zeitung,' April 25, p. 274), assumes that the nucleus of the 

 zoospores of Ulothrix does not exist during its wandering period, and 

 is reconstructed afresh at tho moment of germination. I have tried 

 to verify these assertions by the aid of very precise methods of ob- 

 servation, which I have long employed in the investigation of the 

 nucleus and nucleolus of the Infusoria ; and in the zoospores of 

 Microspora Jloccosa and of an undetermined (Edogonium I have found 

 a very distinctly characterized nucleus. 



I placed upon the glass plate a small drop full of zoospores of 

 Microsporia covered it with the thin glass, and drew away the water 

 by aspiration, so that the zoospores were slightly compressed and 

 rendered nearly motionless. I then cemented two of the opposite 

 edges of the covering-glass with paraffin ; and when it was well 

 fixed I caused a drop of alcohol to penetrate beneath it by drawing 

 off the water with bibulous paper. The zoospores were quickly 

 killed, and retained by compression between the two plates of glass. 

 I then replaced the alcohol with water, and the latter with saturated 

 picrocarminate. In a few minutes, the action of the reagent being 

 sufficient, I drew it off and replaced it by water, always by means 

 of bibulous paper, and then replaced the latter by cry stall iza Me 

 acetic acid. This last reagent, immediately clears the object; and 

 there is then seen, in the rostral region of the zoospores..! small 



