Experiments on the metabolism of matter and energy in the human body / By W.O. Atwater, PH.D., and F.G. Benedict, PH.D., with the cooperation of A.W. Smith, M.S., and A.P. Bryant, M.S.

  • Atwater, W. O. (Wilbur Olin), 1844-1907.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Experiments on the metabolism of matter and energy in the human body / By W.O. Atwater, PH.D., and F.G. Benedict, PH.D., with the cooperation of A.W. Smith, M.S., and A.P. Bryant, M.S. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

    16/124 (page 10)
    shown by the sooty flames and odors. An attempt was made to secure a wick Iree from carbon by tbe use of asbestus, but owing to the poor capillarity of the latter a constant rate of combustion could not be maintained. Various nioditications of tlie method by the use of asbestus were tried, but without success. Hither the rate of combustion could not be regulated or the oxidation was not complete. The method of securing the com])lete combustion of ethyl alcohol, which proved most satisfactory and was afterwards used in the alcohol tests of the accuracy of the measurements of carbon dioxid, water, and heat in the calorimeter, was as follows: The essential feature of the Hame was a central draft of air. To secure this an ordinary small kerosene lamp with an Argand burner and chimnej'was found very satisfactory; that is to say, the alcohol was used in this simple lamp in exactly the same way that kerosene would be burned. The liame of tlie burning alcohol was nonluminous, but it still remained to show conclusively thai, there was no trace of unoxidized material in tlie vapors Irom the burning alcohol. If the supi)ly of oxygen is insuflicient, several i)roducts are, at least theoret- ically, capable of being formed. Such products are carbon monoxid, aldehyde, acetic acid, and hydrocarbons. In or<ler to test for these corni)ounds, it is first necessary to free them from the carbon dioxid and water—that is, from tlie produ(;ts of com- plete combustion of the burning alcohol. For this purpose the lamp in which the alcohol was burning was placed under an inverted funnel, the stem of which was sealed to a glass tube connected with a system of tul)es and solutions lor the removal of diflereut combustion ])roducts from the air. A strong suction from a water pump maintained a cur- r«'nt of air througli tlie whole system, so that a large proportion, assumed to be nearly all, of the jiroducts of combustion were drawn in and through the apparatus along with some of the air from the room. The current thus i)assing in at the inverted funnel was first drawn through bottles containing a saturated solution of caustic potash, which sufficed for the removal of ])ractically all the carbon dioxid and water, as well as volatile li(|uids formed from the incomplete combustion of the alcoliol. Tests for su(;h substances were subsequently made by another method. For the removal of the last traces of carbon dioxid, soda lime contained in Utnbes, was (•mi)loyed. A clear solution of barium hydroxi<l inserfe«l in the system showed that the removal of carbon dioxid was (•oiii])lete. (Jaseous hydroiarbons and carbon monoxid that might have been formed by incom]>let('! oxidation of the alcohol are practically insoluble in caustic jKitasli solution, and their ju-esencM' in the air current freed from carbon dioxid is <'asily established by passing the air through a. short combustion tube containing granulated cupric oxid heated to red nesH, and finally throiigli a solution of barium liydroxid. In this way any incompletely oxidized gas would be oxidized to carbon dioxid, which wouhl proihn-e, a turbidity or j»recipitate in this latter solution.