COMPOSITION OF LYMPH. 333 



transparent, presenting but few granulations and an indistinct nuclear appearance in 

 their centre ; but others are granular and quite opaque. They present the same adhesive 

 character in the lymph that we have noted in the blood, and frequently they are found 

 collected in masses in different parts of the lymphatic system. Treated with acetic acid, 

 the corpuscles generally become swollen and are rendered very transparent, then pre- 

 senting from one to four or five nuclear concretions in their interior. In all other re- 

 gards, these bodies present the same characters as the leucocytes of the blood, and they 

 need not, therefore, be farther described. 



We have already alluded to the fact that the lymph-corpuscles are more abundant in 

 the larger than in the smaller vessels, and that they have been thought to be particu- 

 larly numerous in the vessels coming from the lymphatic glands. It is nevertheless true 

 that corpuscles exist even in the smallest vessels, and they are sometimes quite abundant 

 in lymph which has not passed through the glands. These considerations naturally lead 

 to the theory of the development of leucocytes in the lymphatics, as well as in the ordi- 

 nary vascular system, particularly as the constant discharge of lymph and chyle into the 

 blood-vessels renders it more than probable that most of the leucocytes found in the 

 blood are derived from the lymph. 



The researches of Robin, and of others, by whom his observations have been some- 

 what extended, have conclusively demonstrated that leucocytes may be developed, under 

 proper conditions, in a clear, structureless blastema, without the intervention of any 

 glandular organ ; and, farthermore, it is not necessary that the blastema should be en- 

 closed in any system of vessels. These facts refute completely the idea that the lymph- 

 corpuscles are formed exclusively either by the lymphatic glands or by the walls of the 

 lymphatic vessels. Observations have also shown that leucocytes exist in the blood of the 

 embryon before any lymphatic vessels can be demonstrated ; a fact which shows that 

 these bodies may be developed de novo in the blood-plasma. 



As regards the lymph, there is no fluid in the body which is placed under conditions 

 more favorable to the development of leucocytes. It is enclosed in a system of ves- 

 sels possessing extremely thin walls and undoubtedly subjected to active osmotic cur- 

 rents. It contains, likewise, a considerable quantity of coagulating matters ; and the 

 proportion of these principles has always been found to influence the rapidity of the devel- 

 opment of white corpuscles. Its circulation is not very rapid, and the obstacles to the 

 current which are presented in the lymphatic glands undoubtedly give time for the per- 

 fection of the structure of leucocytes. It is in this way that the increase in the number 

 of leucocytes as the lymph passes from the periphery to the larger vessels, and especially 

 as the fluid passes through the glands, can be explained. 



From the fact that leucocytes are developed before the lymphatic system makes its 

 appearance, that they are found in lymph which has never passed through lymphatic 

 glands, and from observations showing their spontaneous formation in an amorphous 

 blastema, it is the inevitable conclusion that nearly if not quite all of the lymph-cor- 

 puscles are developed by genesis in the clear lymph-plasma, and that their development 

 goes on as the fluid circulates toward the venous system. With regard to the influence 

 of the lymphatic glands upon the generation of leucocytes, there is no evidence that the 

 corpuscles which are developed in the course of the lymph through these organs are not 

 here, as elsewhere, formed simply from the blastema ; and it is not necessary to invoke 

 any special formative action taking place in the peculiar structures of the glands. 



The function of the lymph-corpuscles is obscure. They are discharged into the blood, 

 of which they form a constant constituent. Aside from the hypothesis that they are 

 concerned in the formation of the red blood-disks, no definite and reasonable theory of 

 their physiological office has been proposed. 



In addition to the ordinary leucocytes and a certain number of fatty granules, a few 

 small, clear globules or granules, about y^Vfr of an inch in diameter, called sometimes 

 globulins, are almost constantly present in the lymph. These are insoluble in ether and 



