Muscular and Pulmonary Tissues. 357 



milation. This partly assimilated colloid material has the same 

 composition as that of the insoluble fibres; indeed I shall be 

 able to show that the whole of the colloid material destined to 

 become assimilated has the same composition as the fully deve- 

 loped and insoluble tissue; so that the passage from fluid to 

 solid is a mere morphological change. 



I must now state how the composition of the above three 

 different classes of materials was determined, these materials con- 

 stituting : — 



1st. The fibrous insoluble mass; 



2nd. The colloid fluid, destined to form the insoluble mass; 



3rd. The crystalloid solution, destined to remove from flesh 

 the effete material it contains. 



A few words will suffice, I trust, to make the method of ana- 

 lysis quite clear. Having prepared the extract of 200 grammes 

 of flesh with 500 cub. centims. of water as stated above, the 

 albumen, phosphoric acid, and potash, with the soda and chlorine, 

 it contained were determined. On the other hand, the fibrous 

 mass in the muslin, after the estimation of its water, was sub- 

 mitted to analysis for the determination of the same substances 

 (with the exception of chlorine), and also of its nitrogen, 

 which was done by combustion with soda-lime. The water 

 (estimated by desiccation) represented the bulk of the extract 

 left after straining the fibrous mass ; and the composition of 

 this portion of the extract (retained in the fibres) was calcu- 

 lated from that which had been found for the solution separated 

 from the flesh by extraction. Now, by subtracting respec- 

 tively the numbers obtained for the constituents of the por- 

 tion of the extract retained in the fibrous mass from those 

 found for the constituents of this fibrous residue, it is obvious 

 that the result represented the composition of fibrous mass free 

 from extract. The composition of the colloid material in solu- 

 tion destined to nourish the tissue was calculated from that of 

 the insoluble fibrous mass (insoluble fibrous mass considered 

 free from extract), assuming that the relation the constituents 

 held to each other in both cases was the same — an assumption 

 which I shall show to be correct. The proportion of albumen 

 assimilated, calculated from the nitrogen found in the insoluble 

 fibres, and of soluble albumen in the total colloid solution, were 

 taken as starting-points for the calculation. 



Finally, the composition of the crystalloid material was cal- 

 culated by adding together the numbers representing the pro- 

 portions of the constituents of the insoluble fibres and nutritive 

 colloid solution, and subtracting the result from the total quantity 

 of each constituent respectively found in 200 grammes of flesh. 

 A simple way of explaining this will be as follows. Let the 



