50. What is said of oxygen? 51. Of hydrogen? 52. What is said of
carbon? 53. Of nitrogen? How is ammonia formed? 54. What is said of
phosphorus? 55. What is said of sulphur? 56. Of chlorine?

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57. PROXIMATE ELEMENTS are forms of matter that exist in organized
bodies in abundance, and are composed chiefly of oxygen, hydrogen,
carbon, and nitrogen, arranged in different proportions. They exist
already formed, and may be separated in many instances, by heat or
mechanical means. The most important compounds are _Al-bu'men_,
_Fi'brin_, _Gel'a-tin_, _Mu'cus_, _Fat_, _Ca'se-ine_, _Chon'drine_,
_Lac'tic acid_, and _Os'ma-zome_.

58. ALBUMEN is found in the body, both in a fluid and solid form. It
is an element of the skin, glands, hair, and nails, and forms the
principal ingredient of the brain. Albumen is without color, taste, or
smell, and it coagulates by heat, acids, and alcohol.

_Observation._ The white of an egg is composed of albumen, which can
be coagulated or hardened by alcohol. As albumen enters so largely
into the composition of the brain, is not the impaired intellect and
moral degradation of the inebriate attributable to the effect of
alcohol in hardening the albumen of this organ?

59. FIBRIN exists abundantly in the blood, chyle, and lymph. It
constitutes the basis of the muscles. Fibrin is of a whitish color,
inodorous, and insoluble in cold water. It differs from albumen by
possessing the property of coagulating at all temperatures.

_Observation._ Fibrin may be obtained by washing the thick part of
blood with cold water; by this process, the red globules, or coloring
matter, are separated from this element.

60. GELATIN is found in nearly all the solids, but it is not known to
exist in any of the fluids. It forms the basis of the cellular tissue,
and exists largely in the skin, bones, ligaments, and cartilages.

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57. What are proximate elements? Do they exist already formed in
organized bodies? Name the most important compounds. 58. What is said
of albumen? Give observation relative to this element. 59. Of fibrin?
How does albumen differ from fibrin? How can fibrin be obtained? 60.
What is said of gelatin?

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_Observation._ Gelatin is known from other organic principles by its
dissolving in warm water, and forming "jelly." When dry, it forms the
hard, brittle substance, called _glue_. Isinglass, which is used in
t