with Chemistry and the Natural Sciences. 31 7 



many of them, whose chemical composition is similar, do not pos- 

 sess it in the same degree. This difference in this respect ne- 

 cessarily indicates one also in the grouping of the minute par- 

 ticles. 



We can now, with the help of circular polarization, distin- 

 guish in a great many solutions whether there is only a mixture, 

 or chemical combination ; we can trace, in the organs of vege- 

 tables, the conversion of the gum into saccharine matter, and be 

 present, as it were, at the various elaborations of the sap. 



If to these means of investigation we add the use of the mi- 

 croscope for the investigation of the organization of the fecula, 

 the gluten, the pollen, and the various tissues of plants, as this 

 has within these few years been done, we may then form some 

 conception of the services which natural philosophy may render 

 to organic chemistry. 



The elemental powers of bodies, of whatever nature, have 

 such direct relations with heat, that their reciprocal effects should 

 be studied simultaneously. These effects, however, are so well 

 known, that we need not insist upon them at present. We shall 

 confine ourselves to the relation of some new results which de- 

 monstrate the influence which the recent discoveries in natural 

 philosophy exercise upon physiology. 



It is pretty generally known that we can now, with very great 

 accuracy, determine the temperature of the structures and fluids 

 in living animals, and without inducing disorder, by means of 

 instruments which indicate instant effects, and much more accu- 

 rately than is done by thermometers of the common construc- 

 tion. The experiments which have been made two years ago 

 upon animal temperature, required that they should be repeated 

 in valleys, and in the highest mountains. In proportion as one 

 ascends, the respiration becoming quicker owing to the exeition, 

 it is necessary to enquire if the aniaial tempei'ature does not then 

 undergo particular changes. Particular experiments have been 

 made on this point by M. Brechet and myself at Martigny in 

 the Valais, and at the hospice of the Great Saint-Bernard, where 

 the monks, with the greatest coraplacency, supplied every con- 

 venience for our investigations, and several of them even assisted 

 in our researches. We have foimd that tliere docs not exist any 

 appreciable difference betwixt the temperature of man's muscles 



