510 



CELLULAR TISSUE. 



strictw, t. ccllularis stipatus), because it is 

 proper to the several constituent parts of the 

 body, investing each of them, and penetrating 

 into their internal structure. 



Of the common cellular membrane. It is in 

 this division that the connection to which we 

 have just referred is most free. Thus in the 

 subcutaneous tissue placed between the skin 

 and the fasciae of the muscles, there is an uni- 

 versal and evident communication. Again, 

 in the head, the cellular membrane of the exter- 

 nal parts communicates with that of the internal 

 through all the natural apertures through the 

 foramina of the base and other regions of the 

 skull. From the face and cranium the con- 

 nexion may readily be traced to the neck, 

 whence, after having pervaded all its parts, it 

 passes in one direction behind the , sternum 

 and upper ribs to the thoracic cavity ; and in 

 another underneath the clavicle and scapula on 

 either side, to the arm-pit, which may be re- 

 garded as the common point of junction be- 

 tween the cellular substance of the neck, the 

 trunk, and upper extremity. 



The cellular tissue of the thorax is continuous 

 with that of the abdomen through the openings 

 of the diaphragm, and particularly beneath the 

 sternum, around the aorta, the inferior vena 

 cava, and the oesophagus. In a similar manner 

 the connexion may be followed from the abdo- 

 men to the pelvis ; from the former of these 

 cavities under the crural arch to the inguinal 

 region, which constitutes the point of union 

 between the trunk and the lower extremity; 

 whilst from the pelvis the communication ex- 

 tends in one direction by the side of the rectum 

 and urethra to the perineum, scrotum, and 

 penis ; and in another by the obturator fora- 

 men and the ischiatic notch to the thigh. 



In addition to these, which are the principal 

 connexions, the common cellular membrane is 

 united in every direction with the special di- 

 vision ; the details, however, of these commu- 

 nications belong to the descriptive anatomy of 

 the several regions, to the articles on which'the 

 reader is referred. 



The quantity of the interstitial tissue varies 

 according to the age and temperament of the 

 individual, and to the region of the body in 

 which it is examined; but, independently of 

 any original differences which exist, it is well 

 known that the mode of living and habits of the 

 individual have a great influence in this respect : 

 thus an habitual full diet, especially if con- 

 joined with indolence, causes a great accumu- 

 lation of the cellular substance ; whilst, on the 

 contrary, a spare or moderate diet and exercise 

 will reduce it in a remarkable degree. These 

 differences depend, probably, more on the accu- 

 mulation of serous fluid and on the repletion of 

 the bloodvessels, than on the actual increase 

 of the proper filamentous tissue : we can in this 

 manner, and in no other, understand how, by 

 by what in England is called training, the bulk 

 of the body may be so rapidly diminished. 



The proportion of this tissue varies also in 

 the different regions of the body ; but as it is 

 in an especial manner subservient to the pro- 

 duction of free motion, it is principally accu- 



mulated in those parts which are most move- 

 able. It is on this account that it abounds on 

 the face, especially around the globe of the eye 

 and about the cheeks, and also on the forepart 

 of the neck and of the trunk in general. In the 

 limbs it is met with in considerable quantity in 

 the flexures of the joints, in the axilla, the 

 elbow, the wrist, and in the palm of the hand; 

 also in the groin, in the ham, in the front of the 

 ankle, and in the sole of the foot. The super- 

 ficial muscles, which are very moveable, are 

 separated from each other by thicker layers of 

 membrane than the deeper-seated and more 

 fixed. It may also be remarked that those 

 important organs, which are most liable by their 

 structure or connexions to rupture or other 

 effects of external violence, are carefully pro- 

 tected by being lodged in a large quantity of 

 cellular substance. It is thus that we find the 

 pancreas and the kidneys enveloped in this 

 tissue in the abdomen ; the bladder and genital 

 organs in the pelvis ; and the bloodvessels and 

 nerves in all parts of the body. 



Of the special cellular membrane. Each 

 organ in the body is invested in a proper cover- 

 ing of the cellular tissue, and also receives into 

 its interior, processes which envelope and join 

 together its component parts. 



The investing cellular membrane (t. cellu- 

 laris strictus) is united by one of its surfaces, 

 the external, with the general cellular tissue, 

 and by the other or internal with that entering 

 into the organ. It presents many peculiarities 

 as to the mode of its connexion ; the solid 

 parts, for instance, as the glands, muscles, and 

 nerves, are entirely surrounded by cellular 

 envelopes ; and a somewhat similar disposition 

 is observed around the bloodvessels, lympha- 

 tics, and excretory tubes. On the contrary, 

 the skin, the mucous and serous membranes, 

 having one surface free or unattached, are only 

 connected on one side with the cellular tissue, 

 which is distinguished according to its situation, 

 by the terms subcutaneous, submucous, and 

 subserous cellular tissue. The covering thus 

 afforded to each individual organ serves in a 

 certain degree to insulate and separate it from 

 the surrounding structures, and in this manner 

 it often tends to limit the progress of disease; 

 but as we have just seen that this covering is 

 united both to the interstitial and to the pene- 

 trating cellular tissue, it would be equally con- 

 trary to reason and experience to expect that it 

 should constitute, as some authorities have con- 

 tended that it does, a species of atmosphere 

 around the various organs, confining their natu- 

 ral actions and morbid phenomena. 



The penetrating cellular tissue (t. cellularis 

 stipatus) constitutes so essential a part of 

 organized structures, that there is no organ in 

 which it may not be detected. It exists in 

 the substance of bone, cartilage, and ligament, 

 although it is distinguished in these structures 

 with difficulty, in consequence of their great 

 density ; it penetrates between the most minute 

 fibres of the muscles and nerves; between the 

 coats of the bloodvessels and lymphatics ; also 

 between the layers composing the skin and 

 mucous membranes ; and lastly, it enters into 



