211 



be of very secondary importance, if it be considered, that respiration 

 is not impeded by adhesions between the lungs and the pleura, and that, 

 besides, the brain, which, when the cranium is" whole, is completely mo- 

 tionless, is entirely surrounded by a serous membrane. 



XCVI. Next in order to the serous transudation, which requires a very 

 simple organization, comes the secretion which takes place in the cryptse, 

 in the glandular follicles, and in the mucous lacunae* Each of these 

 small glands, contained within the membranes lining the digestive canal, 

 air tubes, and the urinary passages, and the collection of which forms the 

 amygdalae, the arytenoicl glands, Sec. may be compared to a small bottle 

 with a round bottom, and a very short neck; the membranous parietes 

 of these vesicular cryptae receive a considerable number of vessels and 

 nerves. The peculiar action of the parietes of these different parts, de- 

 termines the secretion of the mucus furnished by those glands. These 

 mucous fluids, less liquid and more viscid than the serosity which is the 

 product of the first mode of secretion, contain more albumen and a great- 

 er number of salts, differ still more from the serum of the blood, are 

 more animalized, and are of a* more excrem'entitious nature. 



The bottom of these ulricular glandulse, is turned towards the parts to 

 which the mucous membranes adhere ; their mouth, or neck, opens on 

 the surface at which those membranes are in contact. These kinds of 

 excretory ducts, wider, or narrower, and always very short, sometimes 

 unite, run into each other, and open within the cavities. These common 

 orifices, at which several mucous glands empty themselves, are easily- 

 seen on the amygdalae, towards the mucous lacunae of the rectum and of 

 the urethra, at the base of the tongue, 8cc. The albuminous fluid, which 

 is poured within those glandular cryptae, remains some time within the 

 cavity, becomes thicker from the absorption of its more fluid parts ; for, 

 there are, likewise, lymphatics within the texture of th^r parietes. When 

 the surfaces, on which they are situated, require to be moistened, this 

 small pouch contracts, and throws up the fluid with which it is filled. 

 The secretion and excretion are promoted by the irritation which the 

 presence of the air, of the aliment, or of the urine occasions, by. the 

 compression exerted by those substances, and lastly, by the peristaltic 

 contractions of the muscular planes to which the mucous membranes ad- 

 here, throughout the whole extent of the digestive tube. 



XCVII. Those fluids which differ much from the blood, require for 

 their secretion, organs of a more complicated nature; such organs are 

 called conglomerate glands, to distinguish them from the lymphatic glands, 

 which have been termed conglobate. Those glands constitute the viscera, 

 and are formed by a number of nerves and vessels of all kinds, arranged 

 in fasciculi, and united by cellular membrane. A membrane peculiar to 

 the organs, or supplied by those which line the cavities in which they 

 are contained, covers their outer part, and insulates them from the neigh- 

 bouring organs. 



The intimate arrangement of the different parts which form the secre- 

 tory glands, the disposition of the arteries, of the veins and nerves, and 

 the manner in which the lymphatic and excretory ducts arise from them, 

 has given rise to endless discussions, and formed the basis of former 

 physiological theories. What follows may be considered as a correct 

 abstract of what is known on the subject. 



The respective arrangement of the simple elementary tissues which 

 enter into the structure of the glands, and. which form their proper sub- 



