26 



flexible membranaceous substance, very similar to the cortical part 

 of some of the Gorgonise ; and in like manner slightly hardened by 

 carbonate, mixed with a small portion of phosphate of lime. 



From this mass of evidence we collect, in general, that the varieties 

 of bone, shell, coral, and the numerous tribe of Zoophytes with which 

 the last are connected, only differ in composition by the nature and 

 quantity of the hardening or ossifying principle, and by the state of 

 the substance with which this principle is mixed or connected; the 

 gluten, or jelly, which cements the particles of carbonate or phos- 

 phate of lime, and the membrane, cartilage, or horny substance 

 which serves as a basis, appearing to be only modifications of the same 

 substance,Vhich progressively graduates from a viscidliquid, or gluten, 

 into a gelatinous substance, which again, by increased inspissation, 

 and by the more or less perfect degrees of organic arrangement, 

 forms the varieties of membrane, cartilage, and horn, which it seems 

 form the peculiar differences of the several species. 



It is obvious that in this inquiry much depends upon an accurate in- 

 vestigation of the gluten, or jelly, so often mentioned as a principal 

 ingredient in the substances under examination. This gave rise to 

 the experiments on the analogous substances above mentioned, which 

 led to a better acquaintance with the substance which now obtains 

 the name of gelatin. 



Not being allowed to enter into a detail of these experiments, we 

 shall only observe at present, that this gelatin is a component part 

 of most of the animal substances above enumerated ; that it varies 

 in quality from a very attenuated jelly or mucilage, to that viscid 

 substance called glue, the varieties of which also differ in solubility 

 and tenacity : that it is present in various proportions, so that certain 

 bodies, such as the cutis and cartilages of the articulations, seem to 

 be entirely formed by it ; while others, like nail, quill and tortoise- 

 shell, can hardly be said to contain any ; and that by its presence in 

 various states and proportions, it may be . regarded as the principal 

 cause of those degrees of flexibility, of elasticity and of putrescibility, 

 so various in different parts of animals. 



In all these substances, when all the gelatin they contained had 

 been separated, either by repeated boiling in water, or by being 

 steeped in dilute acids, a more insoluble substance remained of a 

 very different nature from the gelatin, and which became the object 

 of another extensive analysis. The results here led to the curious 

 and important conclusion, that the substance known by the name of 

 albumen is in fact the primary animal matter from which all the 

 others, and even the gelatin and the animal fibre, are ultimately de- 

 rived, the formation of the two latter beginning with the process of 

 sanguification in the foetus, and the immense variety in the animal 

 creation being deducible from the infinite diversity and modifications 

 in texture, flexibility, elasticity, and other properties of the same 

 substance composing the several parts which constitute the bodies 

 of animals. 



