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.

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    A preliminary test was made by drawing ordinary room air through the apparatus in order to demonstrate the absence of any hydrocarbons or carbon monoxid. The barium hydroxid solution remained clear. The alcolio! lamp previously described was then placed under the funnel of the apparatus and lighted. The flame of the burning alcohol was nonlnminous. Two hundred grams of 90 per cent alcohol was burned at the rate of about 1 gram in two minutes. At the end of this period of nearly seven hours there was no cloudiness in the barium hydroxid solution, indicating that no products of incomplete combustion had passed the potassium hydroxid solution. While such a test as that just described indicates that no gaseous products of incomplete combustion are formed when alcohol is burned in a lamp supplied with an Argand burner, provided tlie flame is non- luminous, it is possible that a considerable amount of liquid products might be formed, and even a trace of alcohol might be volatilized unburned. In order to determine whether such compounds of incomplete oxida- tion were present, a second test was made, in which the products of combustion resulting from the burning of 500 grams of alcohol were passed through two flasks surrounded by a freezing mixture of salt and ice to condense all volatile nongaseous products. The condensed com- pounds, amounting to 150 cubic centimeters, were carefully tested for alcohol and for carbonaceous matter of any kind. A very delicate and easily applied test for small quantities of alcohol has been devised by E. W. Davy.' A few drops of the liquid supposed to contain alcohol is added to a solution of one part molybdic acid in ten parts of strong sulphuric acid and the whole gently warmed in a porcelain capsule. If alcohol is ])resent, a blue coloration apjjears immediately or after a few moments, even when the solution contains no more than 0,1 per cent of alcohol. Before applying this test to the condensed products of the combus- tion of alcohol the liquid was first subjected to two fractional distillations, thereby concentrating the volatile products, if such existed, to about 15 cubic centimeters. A few drops of this distillate was tested in the manner just indicated, but the entire absence of any blue coloration in the molybdic solution implied the absence of alcohol. The delicacy of the test was verified by means of a very weak alcoholic solution of known strength. Since the test is sufficiently delicate to show the presence of even 0.1 per cent of alcohol in a solution, it is evident that there could not have been as much as 15 milligrams of alcohol in the condensed i)roducts of the combustion of 500 grams of alcohol. In other words, if any were present, there must have been less than 3 parts in 100,000. It remained, however, to show the absence of any organic matter in the condensed liquid. Accordingly air freed from all traces of carbon dioxid was passed over the remaining portion of the distillate and the 'Allen, Commercial Organic Analysis, 2. ed., Vol. I, p. 59.