Introduction to Animal Morphology. 7 



observed that the following inorganic materials are 

 found in animal bodies : — Oxygen in all the fluids. 

 Hydrogen in the intestinal gases of vertebrates 

 with H2S, Carbonic acid in all tissues, Calcium 

 Fluoride in bones and corals, Magnesium Fluoride in 

 some corals, "Water in all tissues from enamel which 

 contains 0*2 per cent, to the connective tissues of jelly 

 fishes with 99-5 per cent., Sodium Chloride also in all 



Peptone is a dialysable form of albumen formed in the process of 

 digestion, not precipitable by heat, dilute acids, nor alkalies. 



Fibrin is insoluble in water or NaCl, swells in dilute acids, and this 

 softened form is coagulated on boiling ; found in blood. 



Casein is probably a mixture of Alb. with a non-albuminous substance, 

 which is separated from it in digestion as a dyspeptone ; soluble in alkalies, 

 coagulable by mineral acids, precipitable by lime and magnesia salts, in- 

 soluble in water or NaCl. 



Keratin, the material of the cell-wall in epithehum, resembles casein 

 in many of its properties ; it may be a compound of several albumen- 

 derivates. 



Gerhardt regards these as similar in composition, but differing in 

 molecular arrangement. Lebonte and others regard them as each com- 

 posed of several radicles united in different proportions. From these are 

 derivable the foUowing nitrogenous non-albuminoids : — 



Protagon, present in nerve tissue. A mixture of Cerebrin C17H33NO3, 



O1C16H31O 

 with Lecithin, a body derived from \ O1C18H33O 



Glycerin CaH'-'s ) OiPO /OH 



1 OCjHi (CH3)3NiOH. 



Leucin CeHu (NH2) O2 present in the tissues of Arthropods, in 

 pancreatic juice, &c. Tyrosin CgHuNOj found with Leucin and in 

 Cochineal. 



Kreatin CiHgNsO^HoO in smooth muscle, and with Kreatinin (C4H7N3O) 

 in blood and muscle. Giianin C3H5N5O in Cestodes and Siphonophora, 

 fishes and birds. ^Sar^m in the muscles of hares and ruminants. Xanthin 



C5H4N4O2, and Urea CO | -j^tj^ and Uroxanthin in urine. Chlorophyll 



CieHaoNsOs in Turbellaria and some green annelids. Mucin in mucus, 

 connective tissue, synovia. Limacin and Heliciit are two varieties of it in 

 the slime of Mollusca. Collagen, in the intercellular substance of fibrilloj 

 connective tissue is converted into Gelatin by boiling water or boiling 



