PROTEIN, AND GLUTEN. 
23 
a product of organization, I do not believe. I may illustrate my views in this way : Bone 
is a homogeneous product of organization : so is fibrin, casein, etc. When these bodies, 
however, are washed with water, alcohol and ether, the extractive matter, fat and oils are 
removed. If we now subject them to the action of hydrochloric acid, we remove the solid 
matters, and we have remaining a flexible cartilaginous body of the original shape of the 
bone. So if we subject bone to incineration, we remove all but the solid parts : we have 
the earthy matters remaining. In this case, neither the cartilage nor the solid phosphates 
could say ‘ I am firstfor the fact is, the fluids, which form bone, contain simultaneously 
the special elements which are destined to form it. So it may be said of protein, that it 
never forms a tissue in its independent capacity : the elements of protein, as given in the 
formula, must be in combination with other bodies in order to form the tissues. These 
elements are all removed by the treatment to which the juices, tissues, etc. have been sub¬ 
jected. Cartilage of bone is far more likely to be formed in a state free from phosphate of 
lime; this, however, would be an abnormal state. So bone not unfrequently contains too 
much bony matter; and both bone and cartilage may be insulated by proper treatment, 
yet no one would have a right to call either normal bone. The insulation of protein from 
albumen and fibrin or casein, is an extraction by chemical affinity analogous to cartilage 
in bone ; a matter, which never exists in an independent state. If, from proteine bodies, 
the fat and extractive matter is removed, leaving the inorganic substances, I believe it is 
in the condition in which it forms tissues. Fat, starch, oil, sugar, and analogous bodies, 
are the only ones which are destitute of inorganic matter. Even starch leaves a residue 
on burning, but I am unable to determine whether it is accidentally present or not. 
The foregoing bodies exist in the animal and vegetable kingdoms. There are other 
bodies, however, which are found only in one : thus, gum and starch belong to the vegeta¬ 
ble kingdom exclusively; while gelatin, or rather gluten, and chondrin, are products of 
the animal kingdom only. So pus or pyin, pepsin, and ptyalin, are also exclusively of 
animal origin. Only two of these bodies require a notice in this place, viz. gluten and 
chondrin. 
Gluten. In its ordinary state and condition, it is gelatin or glue. Two distinct sub¬ 
stances, closely related to each other, are obtained from skin, cartilage and bone, namely, 
gluten and chondrin. The former is obtained by boiling serous membranes, skin, etc. 
in water : whefi cold, it forms a tremulous jelly. Chondrin is obtained by boiling the 
cartilage of the ribs, or larynx : when cold and dried, it is hard and brittle. Both 
bodies behave alike when their solutions are treated with acetates of lead, sulphate of iron, 
chlorine and iodine : they form precipitates, which are not soluble in an excess of the 
precipitating substance. Alcohol also precipitates gelatin from its solutions. Tannin 
(tannic acid) is the proper test for gluten or chondrin. 
Glycicoll is a species of sugar produced from gelatin, by boiling it with potash : it is the 
sugar of gelatin, and crystallizes in colorless rhombs from a spirituous solution. 
The origin of gelatin is unknown, except that it is an animal product. It leaves a resi¬ 
due on being incinerated. It is supposed, however, that it is formed in the organism by the 
