308 Jloyal Society. 



a Contribution to the Physiology of Cells.' " By Martin Barry, M.D., 

 F.R.S. L.&Ed*. 



In the paper referred to, the author had shown, that after the ovum 

 of the Rabbit has entered the Fallopian tube, cells are found col- 

 lected around its thick transparent membrane or " zona pellucida"; 

 which cells, by coalescing, form a thinner membrane — the incipient 

 chorion. He now adds, that the formation of this thinner membrane 

 does not exhaust the whole layer of these cells ; but that a stratum 

 of them is found remaining on, and entirely surrounding the " zona," 

 after the thinner membrane has risen from it. The fluid space also, 

 between the " zona" and the thinner membrane, presents a large 

 number of cells or discoid objects, each of which contains a bril- 

 liantly pellucid and highly refracting globule. In some parts, several 

 of these discs, closely joined together, have the appearance of shreds 

 of membrane ; in others, there are found pellucid globules, some of 

 which are exceedingly minute. The discs now mentioned collect 

 at the periphery, for the thickening of the chorion. They seem to 

 proceed from the region of the "zona;" and probably have their 

 origin in the cells by which the latter is surrounded. If so, the au- 

 thor thinks we cannot suppose them to arise in any other way than 

 that which, according to his observations, appears to be the universal 

 mode of reproduction ; namely, by division of the nuclei of the pa- 

 rent cells. Nor can we suppose that minuteness is any hinderance 

 to their subsequent increase by the same means. 



December 17, 1840. — 1. "Present state of the Diamond Mines 

 of Golconda." By T. J. Newbold, Esq., of the Madras Army, A.D.C. 

 to Major-Genei"al Wilson, K.B. Communicated by S. H. Christie, 

 Esq., M.A., Sec. R.S. 



The author gives an account of the tract of country in which the 

 diamond mines of Golconda are situated, and of the processes by 

 which the diamonds are obtained. The latter consist merely in 

 digging out the rolled pebbles and gravel, and carrying them to small 

 square reservoirs, raised on mounds, having their bottom paved with 

 stones, and then carefully washing them. Dry weather is selected 

 to carry on these operations, in order to avoid the inconvenience and 

 expense of draining. A description is then given of the mines of 

 Banaganpully, Munimudgoo, Condapilly, Sumbhulpoor, and Poonah 

 in Bundlekund. 



2. " Magnetic-term Observations made at Milan." By Professor 

 Carlini, Director of the Observatory at that place : also " Magnetic- 

 term Observations made at Prague." By Professor Kreil, Director 

 of the Observatory at that place. 



3. " On the Production of Heat by Voltaic Electricity." By J. P. 

 Joule, Esq. Communicated by P. M. Roget, M.D., Sec. R.S. 



The inquiries of the author are directed to the investigation of the 

 cause of the different degrees of facility with wliich various kinds of 

 metal, of different sizes, are heated by the passage of voltaic elec- 

 tricity. The apparatus he employed for this purpose consisted of a 



* [An abstract of Dr. IJavry's Third Scries of Researches in Embryology 

 appeared in L. and E. Phil. Mag., vol, xvi. p. 526; vol. xvii. p. 385. — Edit.] 



