218 



LYMPHATIC AND LACTEAL SYSTEM. 



The colour of the lymphatic gland, depending 

 apparently on the contents of its bloodvessels, 

 is of a pale rose pink, resembling in this re- 

 spect the colour of the salivary glands or of the 

 cineritious matter of the brain ; the exceptions 

 to this observation will be found in the mesen- 

 teric glands while the chyle is passing through 

 them, when they assume a whitish colour ; the 

 lymphatic glands in the neighbourhood of the 

 liver and gall-bladder have been observed to 

 possess a slight yellow tinge, but this is to be con- 

 sidered a post-mortem appearance. The black 

 colour of the bronchial glands is remarkable and 

 not easily accounted for ; the lymph passing 

 from the lung to them being always perfectly 

 transparent and colourless. 



The lymphatic gland has a capsule of con- 

 densed cellular tissue, which surrounds it and 

 firmly adheres to it, appearing to send cellular 

 prolongations into its substance ; the outer sur- 

 face of this capsule is connected to the surround- 

 ing textures by a loose cellular tissue. The 

 capsule appears to serve the purposes of convey- 

 ing the bloodvessels to the interior of the gland, 

 of isolating it from the surrounding parts, and 

 of preventing its over-distension by the lymph 

 conveyed to it. 



The bloodvessels of the lymphatic glands art; 

 large and distinct; frequently more than one 

 artery is traced to a gland ; the returning veins 

 do not generally correspond either in direction 

 or number with the arteries. The veins are 

 much larger, but have appeared to me fewer in 

 number than the arteries. 



Nerves of considerable size pass to the lym- 

 phatic glands and can generally be traced 

 through them, from which circumstance it has 

 been doubted whether any filaments are left in 

 the land; but if acute sensibility to pain from 

 undue pressure or from disease be admitted as 

 dependent upon a proper supply of nerve, un- 

 doubtedly they possess it. The exact mode of 

 arrangement of the bloodvessels in the interior 

 of the gland is not well known. After a success- 

 ful injection of these vessels the gland assumes 

 the same colour as the injection itself. 



Our knowledge of the structure of the ab- 

 sorbent glands rests mainly upon the informa- 

 tion obtained by throwing injections of mercury 

 or coloured wax into the lymphatic vessels. In 

 this mode of investigating their texture, the walls 

 of the canals or cavities containing the injection, 

 which appear, as in the kidney and testicle, to 

 form the parenchyma of the organ, are com- 

 pressed, and when dry become transparent. 

 The arrangement of the minute bloodvessels on 

 the lining membrane of these canals has not 

 been sufficiently investigated, and until this 

 has been effected, our knowledge of the structure 

 and function of the lymphatic gland must be 

 considered very unsatisfactory, and as consist- 

 ing of little more than conjecture. The great 

 point of controversy has been, whether the in- 

 jection thrown into the gland by the afferent 

 lymphatic vessels was contained in cells or in 

 convoluted vessels, which if decided would 

 throw but little light upon the office performed 

 by the gland a desideratum in physiology of 

 considerable importance, and without which 



we are left in the dark at the very threshold 

 of our investigations with respect to the first 

 changes effected in the lymph and chyle, in 

 advance towaids sanguification. On examining 



Fig. 52. 



Lymphatic glands injected with mercury. 

 (After Mascagni.) 



A, gland injected and dried, a, a, vasa affe- 

 rentia. b, vasa efferentia. 



B, gland injected and laid open to show the appa- 

 rent cells, i, apparent cells ; e, vas efferens ; a, 

 vasa afferentia. 



the glands thus distended with injections, the 

 vasa inferentia are seen reaching the eland 

 from various sources, and on their approach to 

 it they may be observed to subdivide into ex- 

 tremely minute branches, which disappear by 

 plunging into its substance : equally minute 

 vessels may be observed emerging from its 

 opposite side or surface, which soon unite to 

 form the vasa efferentia of the gland ; the gland 

 itself, which is intermediate in position between 

 these vessels, when injected, presents a gra- 

 nular surface, and at first sight an observer 

 would generally conclude that he was look- 

 ing upon minute cells filled by the injection ; 

 in making a section also into the substance 

 of the gland and allowing the mercury to 

 escape, the appearance on a superficial in- 

 spection is still that of cells ; proceeding, 

 however, with more attention to examine these 

 supposed cells, especially after making a section 

 as close to the surface of the gland as possible, 

 by the aid of the microscope it will be evident 

 that tubes closely set together and adherent to 

 each other, have been laid open, passing in 

 various directions, and in their interior many 

 valvular constrictions and thread-like intersec- 

 tions may be seen ; in fact the gland appears 

 to be entirely composed of a convoluted vessel, 

 the sides of which as they come in contact are 

 firmly held together by cellular membrane 

 derived from the capsule. 



This convoluted tube forming the gland is not 

 always cylindrical, but is occasionally dilated, 

 and looks flattened near the surface where 

 pressed by the capsule ; the size of this tube 



