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 ceise, neither the cartilage nor the solid phosphates 

 could say ' I am first ;' for 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, wouM 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 aflinity 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 : when 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. 



GlycicoU 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 



