628 



size from the outer to the innermost cell, and vary in number from 

 fourteen to twenty-six. In some instances, small papillae are ob- 

 servable on the external surface of the integument, which are pro- 

 bably vestiges of the bases of the pseudopodia or tentacula. 



Drawings of the various specimens described by the author ac- 

 company the paper. 



" Microscopic Observations on the so-called Vesicular Vapours 

 of Water as existing in the Vapours of Steam, and in Clouds," &c. 

 By A. Waller, M.D. Communicated by P. M. Roget, M.D., Sec. R.S- 



From some experiments, of which the author published an ac- 

 count in the Philosophical Magazine of last February, he was led 

 to conclude that the opaque vapours of condensed steam consist of 

 minute globules or spherules of water, and not of small vesicles, as 

 is implied in the generally received theory, according to which this 

 condition of water is designated by the term vesicular vapour. In 

 the present paper, he relates a set of experiments confirming by mi- 

 croscopic observation his views of the globular condition of the par- 

 ticles of opaque vapours ; premising a short retrospect of the opi- 

 nions of Sir Isaac Newton, Halley, Kratzenstein, and De Saussure 

 on this subject. Finding it impossible to observe the globules with 

 any high magnifying power while they are at liberty to move, the 

 author adopted the plan of fixing the condensed vapours arising 

 from the breath or other sources, in some liquid, such as oil, which 

 has no affinity with water. Of the many vehicles which he has 

 tried, he finds Canada balsam to be that which is best adapted for 

 these observations. By breathing with a little force on a slip of 

 glass previously covered with a thin layer of balsam, the vapours of 

 the breath are not only condensed on its surface, but penetrate be- 

 neath, where they may be recognised in opaque streaks of a white 

 colour, and where they remain stationary for more than an hour ; 

 or, if covered with another thin piece of glass or talc, for a much 

 longer period. These streaks are decomposed under the micro- 

 scope into minute globules perfectly spherical, like shot, or the glo- 

 bules of mercury. The author describes, at some length, the various 

 appearances presented under different circumstances, and with dif- 

 ferent oily fluids ; and gives drawings of these appearances as exhi- 

 bited by the microscope. 



" Experiments relative to Animal Temperature, showing that there 

 must be some source of animal heat besides the combustion of the 

 Carbon and the Hydrogen contained in the Food of Animals." By 

 Robert Rigg, Esq., F.R.S. 



The subject of these experiments was a labouring man in the em- 

 ployment of the author, living on his ordinary food, and working 

 at his usual employment. A strict examination was instituted into 

 the quantity and chemical constituents of the ingesta and egesta 

 during ten days ; at the end of which time he had gained one pound 

 in weight. He infers from the results of this experiment, that the 

 carbon and hydrogen contained in the food of animals, which enter 



