ZOOLOaY AND BOTANY, MICROSCOPY. ETC. 1019 



to any moderate extent, and that it is not a legitimate conclusion to 

 regard as distinct species forms which differ only by having multiple 

 nuclei. As to the effects of pressure, it seeins certain that " no pressure 

 of any ordinary kind could actually compress a fluid or semifluid sub- 

 stance like sarcode. even in the sliglitest degree." Even if pressure 

 acts, as Gruber thinks, by extracting water, the explanation would not 

 account for the collapse as well as the inflation with fluid of the con- 

 tractile vesicle ; further, the pressure referred to by Dr. Gruber is 

 exercised at the posterior aspect of the Amoeba, and as the contractile 

 vesicle almost always discharges itself in that region, it would be 

 doing so in the teeth of the force which is, at the very same time, 

 exerting itself in projecting pseudopodia in the opposite direction. 



Pseudocyclosis in Amoeba.* — Dr. G. G. Wallich calls attention 

 to the fact that in 1803 f he explained the quasi-circulatory move- 

 ment of particles in the body-substance of Amceba on the same basis 

 as that recently advanced by Mr. S. Lockwood, J and which he con- 

 siders to be the only rational explanation of the phenomena which is 

 Compatible with the readily observable facts of the case. 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



a. Anatomy. § 



Various Degrees of Resistance in Protoplasm. jj — Dr. 0. Loew 

 distinguishes between sensitive and resisting protoplasm, all inter- 

 mediate grades occurring, however, between the extremes. A remark- 

 able sensitiveness is shown, for example, by Sphseroplea, the cell- 

 protoplasm dying with the slightest mechanical impact ; while in 

 Vaucheria the protoplasm which has been pressed out remains long in 

 a living state. A similar difference is exhibited in the effect of 

 chemical reagents. While a 1 percent, solution of ammonium chloride 

 kills Spiror/7jra in a very short time, it is completely unchanged in a 

 solution of O'Ul per cent, until the sixth or eighth day, when a 

 separation of granules takes place in the colourless protoplasm which 

 reduces neutral silver-solutions. In contrast to Sinroijyra, Torula is 

 very resistent to a 1 per cent, solution of ammonium chloride, and 

 will even live in a 10 per cent, solution at 40^ C. ior some time. 



• Amf-r. Mon. Micr. Journ., vi. (1885) pp. 190-3. 



t Ann. and Ma},'. Nat. Hist., xi. (IWA) p. ?.65, xii. (18G3) pp. Ill, 329, and 

 448. Also Mon. Mirr. Journ., i. (18G9) p. 23:3. 



X Arner. Mon. Mier. Journ., vi. (1885) pp. 4G-7. 



§ This .'Ulxlivi.-ion contains (I) Cell-Btruoture and Protoplasm (including the 

 Nucleup and Cell-diviBioti) ; (2) Otlier Cell-contents (including the Cell-eap and 

 Chlorophyll); (3) Stcretiona; (4) Structure of TiKSues; and (5) Structure of 

 Organs. 



II Pflutjcr's Arch, f Gesjrmmt. Physiol , xxxv. (188.5) jip. .')09-16. 



