ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 463 



New Jersey, in which were also Salpse and Medusse, the phosphor- 

 escence of which would not account for the milky glow on the water. 

 He was unable to observe any phosphorescence in the organism itself 

 when examined microscopically, but when alcohol was poured into 

 the water points of light were produced ; damj) sand from the shore 

 exhibited the same phenomenon. At first the author thought the 

 organism was a small species of Nodiluca, but that idea has been 

 given up. In the discussion which followed the reading of the paper, 

 Mr. C. F. Cox suggested that the organism was a bacterium, and con- 

 nected with decay of the Medusse. Dr. N. L. Britten considered that 

 they were zoospores of Medusse, while Prof. D. S. Martin thought it 

 probable that they were a very young stage in the development of 

 Salpa. 



Pulsating Vacuoles of Infusoria.* — M. Z. Fiszer describes his 

 observations on the structure of the vacuoles in Aspidisca lyneeus and 

 Paramecium aurelia, especially with reference to the statement of 

 older observers that the vacuole is separated from the surrounding 

 protoplasm by a special membrane ; he adopts, on the contrary, the 

 more recent view that it is a simple cavity in the interior of the 

 protoplasm-body. In P. aurelia he was able to see directly how the 

 canals which radiate from the vacuoles swell up, after the dis- 

 appearance of the vacuole, till their converging ends meet, and then 

 these swellings coalesce into a new vacuole. 



The author confirms Oscar Schmidt's statement that the pulsating 

 vacuoles communicate with the surrounding water by a special exit, 

 and expel their contents when they contract. This view was confirmed 

 by the observation that in Aspidisca, at the moment of contraction, 

 the vacuole is distinctly renewed outwards. 



As to the physiological function of the vacuoles, the author came to 

 the conclusion that their main purpose is to serve as a means of carrying 

 away the water which has been deprived of atmospheric oxygen, 

 although possibly products of metastasis may at the same time be 

 excreted through them. In all the species examined, as Stylonychia 

 mytilus, S. pustulata, Ghilodon cucullus, Pleuronema chrysalis, Parame- 

 cium aurelia, &c., when placed in water that had been boiled and then 

 rapidly cooled, the vacuoles, instead of pulsating more slowly, behaved 

 in exactly the opposite way, contracting and again expanding three or 

 four times more quickly than in ordinary conditions. An exception 

 was afforded by Acineta mystax, in which water destitute of oxygen did 

 not quicken the pulsations ; but the vacuoles swelled up to three 

 times their original size ; the increased amount of water expelled at 

 each pulsation replacing the increased rapidity of the pulsations. The 

 same results were obtained by gradually replacing the water beneath 

 the cover-glass by boiled water. The phenomenon lasted, however, 

 only for a short time, the Infusoria soon perishing under such 

 conditions. 



The physiological function of the pulsating vacuoles is, from 



* Wszechswiat Warsaw, iv. (1885) (in Polish). Sco Bot. Centralbl., xxv. 

 (1886) p. 34. 



