

GENERAL PHYSIOLOGY OF THE EPITHELIUMS. 



bones), we cannot easily admit of its existence, principally 

 because pathological phenomena do not disclose these spaces 

 in the depths of the organs : indeed, the slightest injury to 

 the epitheliums instantly affects the lymphatic system (lym- 

 phitis, adenitis) ; while injury to the deeper organs, the 

 bones, for instance, gives rise to no such complication, unless 

 the disease proceed from the deeper parts towards the sur- 

 face. 



Along the course of the lymphatic vessels are found gan- 

 glions, whose complicated structure will be better understood 

 after study of their development : they are originally plexus 

 of lymphatic capillaries, ramified, anastomosed, and rolled up 

 into a ball ; the parenchyma, thus formed, retards the flow 

 of the lymph, which crosses it ; and the white globules, which 

 are to be poured into the blood, multiply at these points. 



The origin of the lymphatic system is another of the 

 subjects on which physiologists are least agreed. The new 

 processes of investigation, however, especially injection of 

 nitrate of silver, have enabled us to solve some points of this 

 important question. 



In the first place, it has been demonstrated that, beside the 

 lymphatic vessels subjacent to the tissues, numerous spaces 

 of lymphatic origin are found in the deep-seated tissues, not 

 only in the glands (which are also derived from the epithe- 



laries in the lymphatic vessels of the gland and of the canal of the 

 urethra. 



The bladder, on the other hand, is entirely without lymphatics. 

 Sappey has shown that the trunks in this organ, described by 

 Cruikshanck and Mascagni, do not begin in it, but in the prostate 

 gland, and, in order to reach the intra-pelvic ganglion, pass along 

 the postero-lateral parts of the bladder. The non-absorption of 

 the vesical mucus is sometimes explained by this absence of lym- 

 phatics, but this is really an essentially epithelial phenomenon. 



The lymphatic vessels of the pituitary body have long been a 

 subject of dispute between anatomists. Jn spite of the descriptions 

 of Cruveilhier, Sappey refused to admit of their existence, because, 

 after injection of the vessels, it was impossible to follow them up 

 to their terminal ganglions. Now, since the researches of Simon, 

 Panas, and Sappey, their existence can no longer be denied, for 

 they have been traced as far as the stylo-pharyngeal ganglions, up 

 to a large ganglion situated close to the axis, which is the highest 

 ganglion in the body (Sappey). 



The case is the same with the lymphatic vessels of the oeso- 

 phagus, but those of the palpebral and ocular conjunctiva are still 

 disputed (Sappey). 



