55 .APPENDIX. 



and after periods of various duration have elapsed from the time of their discharge from 

 the body. 



Finally, we may remark that the fluids, being composed of molecules moving with 

 facility on each other, cannot, as the solids, be traced to constituents of an elementary 

 nature. They can only become the subject of microscopic research in our endeavours 

 to trace the nature of their constitution : by this means we can merely learn that they 

 are generally composed of globules, swimming in a fluid substance, and whatever be 

 the fluid employed, we perceive only globules suspended in an amorphous liquid. It 

 should, however, be remarked that, as we find in some solids merely a concreted amor- 

 phous substance containing no globules, as in the cellular tissue for example, so we 

 perceive some fluids destitute of globules and formed only of an amorphous substance, 

 which is perfectly fluid. In other solids and fluids, on the contrary, we h'nd both glo- 

 bules and an amorphous matter, which is concrete in the former and liquid in the other. 

 But these globules vary greatly, both in solids and in fluids, and even in the same part, 

 according to age ; those of the blood, for instance, are composed ci a solid central part, 

 and of an external envelope which is coloured; those of the chyle appear to be the 

 same as the central part of the former without its coloured envelope ; those of the mus- 

 cular fibre seem to be the same as those of the blood ; those of the brain and nerves are 

 smaller than the foregoing ; and those of the kidneys are smaller than those of the 

 spleen. During the first epoch of conception the globules are not visible ; they, how- 

 ever, soon form, and become more and more distinct. See on this subject Physiologic 

 de I'Homm*, par-JV. P. ^Idelon. Vol. 1. p. 116. 



Of the Blood. 

 Note BB. 



I. Of the fimgtt colourless Globules of the Hlood.^-The researches of Sir Everard Home, 

 and Mr. Bauer, (Phil. Trans, for 1820,) seem to lead to the following conclusions re- 

 specting these globules. 



1. That the milk-like fluid, the produce of digestion (cliyle) which is found in the 

 lacteal vessels and glands, contain an infinite number of white globules, chiefly of a 

 minute size. 



2. These newly discovered minute globules are __ * part of an inch in diameter. 



3. That the chyle contains also some white globules of the size of the red globules of 

 the blood. 



3. Mr. Bauer supposes that the full sized globules acquire their form in the lacteal 

 glands. 



5. Sir Everard Home considers that the globules of the blood receive their red hue 

 in the vessels of the lungs. 



6. That lymph or fibrine, whether taken from an inflamed surface, from the buff of 

 \vhat is commonly called inflamed blood, or from the slowly formed layers of aneuris- 

 mal tumours, consists of innumerable white globules, much smaller than those which 

 constitute the red globules of the blood, and similar to those minute globules already 

 described. 



7. That these small globules constitute the substance thrown out in inflammation. 



8. That they are held in solution in the st rum, and consequently are only brought 

 into view in the act of coagulation. 



9. That these globules, as well as those which subsequently receive the red colour, 

 are the produce of digestion, and are formed in the pyloric portion of the stomach, and 

 in the duodenum, surrounded by a glairy mucous, which is met with in these parts. 



M. Prevost and Durnas* agree with Sir Ev. rard Home, as to the form and structure of 



* The microscopic observation of the blood satisfied these gentlemen, that this liquid 

 during life, was nothing else than the serum, holding in suspension small, regular, and 

 insoluble corpuscles. These are uniformly composed of a central colourless spheroid, 

 and of a species of membranous bag 1 , oi' a fed colour, Surrounding this spheroid, from 

 which it is easily separable alter death. The central body is white, transparent, of a 

 spherical form in animals with circular particles ; of an ovoid form, in those with ellipti- 

 cal particles. Its diameter is constant in the first, but it varies very perceptibly in the 



