PHYSICS AND NATURAL HISTORY OF GENEVA. 245 



of tlie different opinions put forth on this subject for twenty-five years 

 past, the result of his own observations on the structure of these ani- 

 mals, accompanied by a series of drawings relative to that structure. 

 He first showed that the general type of the infusoria presents an 

 exterior cuticle covering a parenchyma of more or less thickness, 

 which itself circumscribes the general cavity of the body; the cuticle 

 and parenchyma pierced by two openings, which are the mouth and 

 anus; then, after describing the mechanism of the circulation of ali- 

 ments in the interior of the general cavity of the body, and of their 

 digestion in the same, he passes to the examination of the circulatory 

 apparatus, which he regards as a closed vascular system comparable 

 in all respects with sanguineous systems. After some other details, 

 M. Claparede has indicated what are the natural affinities of infusoria, 

 and what position should be assigned them as animals related on one 

 hand to the vermes tubellarise, and still more on the other to the 

 caelenteres, (polypi and acalephi,) as regards their digestion chiefly, 

 yet differing from them in a radical symmetry of form, while the 

 cselentfires proper are characterized by a radiate symmetry not to be 

 mistaken. 



M. Claparede has likewise communicated his microscopic observa- 

 tions on the organs in the antennae of insects described as auditory 

 by M. Lespes, and has shown that the auditory and otolithic sac 

 imagined by that author is but an optical illusion, and that an exami- 

 nation of transverse sections, delicately conducted, proves those sup- 

 posed organs to be only hairs fantastically modified. In regard to 

 the use of the microscope, he has noticed a singular effect observed 

 in looking, in the direction of its axis, into a very minute capillary 

 tube, which plays the part of a bi-concave lens, although the liquid 

 which fills the tube be the same with that which bathes all the parts 

 of the body in which the tube is pierced, and although the surfaces 

 which limit the liquid be perfectly plane. 



We have yet to recall some other communications by M. Claparede: 

 1st, the demonstration of the electrical organs of the malapterure and 

 the mormyrus oxythyneus, derived from a dissection of these electric 

 fish, specimens of which had been sent him by M. De la Rive; 2d, 

 an examination of the researches of M. Lebert on the malady of silk 

 worms, from which it seems to result that there is no other remedy 

 to be hoped for but the destruction of all the animals attacked; 3d, 

 an account of the experiments of M. Heidenheim relative to the appli- 

 cation of ligatures on different points of the hearts of frogs, the effects 

 of which are entirely contrary, according to the place where the liga- 

 tures are placed; 4th, an analysis of the researches simultaneously 

 but independently made by MM. Kolliker and Wedl, from which it 

 results that the minute channels noticed by English naturalists in the 

 shell of most of the molluscs are due to the action of a perforating 

 vegetable parasite; channels which M. Claparede had himsef distin- 

 guished, in 1855, as not pertaining to the mother shell, but as hol- 

 lowed by some parasite, which he then wrongly judged to be of an 

 animal nature. 



M. Henri de Saussure continued his account of the interesting 



