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612 BRAIN AND NERVES.
chloroform (see page 607), and purifying the separated cerebron from
contaminating phosphatides by precipitating these with an ammoniacal
solution of zinc hydroxide in methyl alcohol, and recrystallizing the cere-
bron from methyl alcohol containing chloroform. Thierfelder and
Loening have devised another method of purification and at the same
time they have suggested another method for preparing cerebron. This
method is based upon the resistance of the cerebrosides to baryta and
their solubility in hot acetone. It consists in boiling the impure protagon
mixture with baryta-water and boiling the insoluble residue with acetone.
Neuridine, C6 Hi4N2, is a non-poisonous diamine discovered by Brieger, and
obtained by him in the putrefaction of meat and gelatin, and from cultures of
the typhoid bacillus. It also occurs under physiological conditions in the brain,
and as traces in the yolk of the egg.
Neuridine dissolves in water and yields on boiling with alkalies a mixture
of dimethylamine and trimethylamine. It dissolves with difficulty in amyl
alcohol. It is insoluble in ether or absolute alcohol. In the free state, neuridine
has a peculiar odor, suggesting semen. With hydrochloric acid it gives a compound
crystallizing in long needles. With platinic chloride or gold chloride it gives
crystallizable double compounds which are valuable in its preparation and detec-
tion.
The so-called corpuscula amylacea, which occur on the upper surface of the
brain and in the pituitary gland, are colored more or less pure violet by iodine
and more blue by sulphuric acid and iodine. They perhaps consist of the same
substance as certain prostatic calculi, but they have not been closely investigated.
Quantitative Composition of the Brain. The quantity of water is
greater in the gray than in the white substance, and greater in new-born
or young individuals than in adults. The brain of the foetus contains
879-926 p. m. water. The observations of Weisbach1
show that the
quantity of water in the several parts of the brain (and in the medulla)
varies at different ages. The following figures are in 1000 parts
—
A for
men and B for women:
20-30 years. 30-50 years. 50-70 years. 70-94 years.
A. B. A. B. A. B. A. B.
White brain-substance. . 695.6 682.9 683.1 703.1 701.9 689.6 726.1 722.0
Gray " 833.6 826.2 836.1 830.6 838.0 838.4 . 847.
S
839.5
Gyri 784.7 792.0 795.9 772.9 796.1 796.9 802.3 801.7
Cerebellum 788.3 794.9 778.7 789.0 787.9 784.5 803.4 797.9
Pons Varolii 734.6 740.3 725.5 722.0 720.1 714.0 727.4 724.4
Medulla oblongata 744.3 740.7 732.5 729.8 722.4 730.6 736.2 733.7
The recent investigations of K. Linnert 2
correspond to the above
in that the pons and the medulla were found to be next to the white sub-
stance, the poorest in water, of the human brain.
Quantitative analyses of human brains at different ages, namely
6 weeks, 2 and 19 years, have been made by Koch and Mann.3
These
analyses show that with increasing age the water, proteins, extractives
1
Cited from K. B. Hoffmann’s Lehrbuch d. Zioch., Wien, 1877, p. 121.
2
Wien. klin. Wochenschr., 23.
• Journ. of Physiol., 36, Proc. physiol. Soc, 1907.
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