198 EPITHELIAL GLOBULES. 



this respect, the lymph must be considered as formed of that 

 part of the liquor of the blood which is not employed for the 

 nutrition of any of the tissues. 



The lymph, in fact, contains excrementitial products of 

 the tissues: it contains extractive matters, especially urea 

 (Wurtz), which is found in larger proportion here than in the 

 blood. The urea here appears as the result of the combus- 

 tion of that quantity which we found was wanting in the 

 liquor of the lymph, in comparison with the liquor of the 

 blood. 



The other elements of the lymph are less important : they 

 are salts, resembling those of the serum of the blood (princi- 

 pally chlorides and sulphates). Schmidt even discovered 

 iron, in small quantities, in ashes of tlie lymph and chyle. 



The lymph, like the blood, contains also gases and these 

 are the same as those found in the blood ; it seemed at first 

 natural to suppose the proportion of oxygen and carbonic 

 acid in the lymph to be the same as in the venous blood : 

 this, however, is not the case. Recent experiments by 

 Hammarsten have proved that the lymph contains less car- 

 borne acid than the venous blood. This fact appears unim- 

 portant, but we shall see its significance when treating of the 

 respiratory combustion which goes on in the deeper tissues. 



The manner in which we interpret generally the relations 

 of the origin of the lymphatic system to the epitheliums will 

 not apply to all : it applies to the skin, the mucous coat of 

 the mouth, and the mucous membrane in general; but in the 

 small intestine the lymphatic network is separated from the 

 epithelium by a blood network : we shall seek to explain 

 this arrangement later, in reference to absorption. The 

 mucous coat of some organs appears to be entirely without 

 lymphatic plexus: as, for instance, that of the urethra, the 

 bladder, the nasal fossa3, the oesophagus (?) 1 In the deep 

 origins of the lymphatic vessels (connective tissue, muscles, 



1 The existence of lymphatics in the mucous coat of these organs 

 has been the subject of numerous investigations. 



According to Sappey, that of the urethra is certainly furnished 

 with lymphatic vessels: they are very fine and thin, and their small 

 branches converge in the frenum of the penis, whence they pass 

 into the ganglions in the fold of the groin; but they communicate 

 behind \vith the lymphatic vessels of the seminiferous organs and 

 of the testicle, which explains the propagation, even to the scro- 

 tum of the blennorrhayic angeioleucitis (Sappey). Belajeff carried 

 on his minute researches as to the structure of the lymphatic capil- 



