A manual of human physiology, including histology and microscopical anatomy, with special reference to the requirements of practical medicine (1885) (14594945629)

Identifier: manualofhumanphy01land (find matches)
Title: A manual of human physiology, including histology and microscopical anatomy, with special reference to the requirements of practical medicine
Year: 1885 (1880s)
Authors: Landois, L. (Leonard), 1837-1902 Stirling, William, 1851-1932
Subjects: Physiology Histology
Publisher: Philadelphia, P. Blakiston, Son, and Company
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library



Text Appearing Before Image:
— The heat of the body is an uninterrupted evolutionof kinetic energy, which we must represent to ourselves as due tovibrations of the corporeal atoms. The ultimate source, of the heatis contained in the potential energy taken into the body with thefood, and with the O of the air absorbed during respiration. Theamount of heat formed depends upon the amount of energy liberated(see Introduction). The energy of the food-stuffs may be called latent heat, if weassume that when they are used up in the body, chiefly by a process of combustion, kineticenergy is liberated onlyin the form of heat. Asa matter of fact, how-ever, mechanical energyg and electrical energy aredeveloped from the poten-tial energy. In order toobtain a unit measure forthe energy liberated, it isadvisable to express allthe potential energy asheat-units. The Calorimeter.—Thisinstrument enables us totransform the potentialenergy of the food intoheat, and, at the sametime, to measure the num-ber of heat-units pro-duced.
Text Appearing After Image:
Favre and Silbcrmann used a water-calorimeter (Fig. 166). The substance to be burnedis placed in a large cylindricalcombustion chamber (K), sus-pended in a large cylindrical vessel (L) filled with water (w), so that the combustionchamber is completely^surrouuded by the water. Three tubes open into the upper Eig. 166.Water calorimeter of Favre and Silbermann. C ALORIMETR Y. 423 part of the chamber; one of them (0) supplies the air which is necessary for combus-tion, it reaches almost to the bottom of the chamber; the second tube (a) is fixed inthe middle of the lid, and is closed above with a thick glass plate, and on this isplaced, at an angle, a small mirror (s) which enables an observer to see into theinterior of the chamber, and to observe the process of combustion at c. Thethird tube (d) is used only when combustible gases are to be burned in the chamber.It can be closed by means of a stop-cock. A lead tube (e, e) with many twists on it,passes from the upper part of the chamber th