Experimental morphology / by Charles Benedict Davenport.

  • Charles Benedict Davenport
Date:
1897-99
Catalogue details

Licence: Public Domain Mark

Credit: Experimental morphology / by Charles Benedict Davenport. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    It would be valuable to kno^y the relative number of atoms of each of the metalloids and metals named in the preceding table. This may be determined in the following way: Find the proportion by weight of each metallic radical (excluding the oxygen) in the entire ash and divide this percentage by the molecular weight of the metal. The varying weights of the elements are thus eliminated, and a set of numbers which indi- cate relative abundance of atoms is obtained. We multiply these small fractions by 1000 for convenience. The results are as follows : — TABLE XXVII >£w-BOKx Dog. Menhadex (Fish). Oat Plaxt. Ca 528 , 715 216 P 555 506 124 K 243 151 974 CI 24 174 173 Na 343 150 60 Mg 45 77 114 Fe 9 — 6 Si — 101 287 S — — 36 These examples may suffice to show how diverse is the com- position of different organisms and how diverse therefore must be their requirements in the Avay of food to build up the adult bod}-. The examples serve also to indicate what are the important elements for organisms. They appear to be the same for animals and plants, and are : — *Carbon *Calcium Sodium *Sulphur *Oxygen *PotassiuirL Chlorine Silicon *Hydrogen *Phosphorus *]\Iagnesium *Iron *Nitrogen While this list does not pretend to exhaust the elements found in organisms, it contains those wliich are usually present. In the organism the atoms just named are, of course, found in combination. The carbon, oxygen, hydrogen, and nitrogen are contained in the organic matter of the organism — the * Those elements which are starred (*) are essential to all organisms.