and Observations on the component Parts of Membrane. 36*5 



which progressively graduates, from a viscid liquid or gluten, 

 into that gelatinous substance which has so often been noticed, 

 and which again, by increased inspissation, and by the various 

 and more or less perfect degrees of organic arrangement, forms 

 the varieties of membrane, cartilage, and horn. 



I shall now attempt to prove what I have here asserted, or 

 at least assign the reasons which induce me to adopt this opi- 

 nion ; but, in so doing, I am compelled, from the close connec- 

 tion of the subject, to anticipate the general result of part of a 

 series of experiments, made with a view to investigate the nature 

 and composition of membrane. 



To enter into a minute detail of these experiments, would far 

 exceed the limits of a paper like the present ; I shall therefore 

 only mention, in a concise manner, the results of those which 

 the subject immediately requires to be brought forward.* 



The method which first presents itself in such an investiga- 

 tion, is, the comparative analysis of the different substances, 

 so that their relative proportions of carbon, hydrogen, and 

 azote, should be precisely determined ; but, when it is recol- 

 lected, how long a time would be requisite for making such 

 an immense series of analyses, and how much animal sub- 

 stances are subject to be modified by situation in the body, by 

 age, and by the degree of health of animals, and also that the 

 nature of these, and even that of the unorganised bodies, does not 

 always merely depend on the proportion of the constituent prin- 

 ciples, but likewise on the degree and mode of combination to 

 which these principles are subjected ; I say that when all this, 



* These are the experiments to which I alluded in my former paper, and which I 

 began at the request of my friend Mr, Home, soon after the experiments on the enamel 

 of teeth, &c. 



