242 ABSORPTION LYMPH AND CHYLE 



These spaces contain a liquid and large numbers of leucocytes. The 

 leucocytes in these spaces may be called lymph-corpuscles, as they 

 eventually find their way into the true lymphatic vessels ; but they 

 are thought to be corpuscles that have passed through the stomata 

 of the capillary bloodvessels. The connective-tissue lymph-spaces, by 

 certain of their branches, finally communicate with the lymph-capillaries, 

 through what have been regarded as the stomata of these vessels. These 

 anatomical data have led to the following view in regard to the relations 

 between the blood, the lymph and the tissues. 



Nutrient matters are supplied to the parts by transudation through 

 the walls of the capillary bloodvessels ; and effete matters pass from 

 the lymph-spaces into the true lymphatic vessels to be carried to the 

 venous system. In certain tissues and organs, however, such as the 

 cornea and fibrous membranes, the lymph-spaces or canals supply 

 the nutrient liquid ; and in the glands, possibly they supply part of the 

 material used in the formation of the secretions. 



In the serous membranes and in analogous structures, there are 

 large numbers of openings into the cavities ; and the peritoneum, pleura, 

 pericardium, tunica vaginalis testis, chambers of the eye, labyrinth of 

 the internal ear and subarachnoid space are to be regarded as lymph- 

 sacs, the contained liquids being lymph, without, however, presenting 

 the so-called lymph-corpuscles. 



The relations between the bloodvessels and the smallest lymphatics 

 are very close in certain parts. In the cerebro-spinal centres, the 

 smallest vessels of bone, the retina and the liver, is a system of canals 

 which completely surround the small bloodvessels and are connected 

 with the lymphatic trunks, or reservoirs, described by Fohmann, and 

 found beneath the pia mater. These are called perivascular canals ; 

 and the contained liquid is true lymph, containing leucocytes. They 

 exceed the bloodvessels in diameter by y^Vo" to wo f an mc ^ ( 2O to 

 62 p). 



The capillary lymphatics have been studied in various parts by 

 means of mercurial injections ; but the presence of valves in the small 

 trunks renders it necessary to make these injections from the periphery. 

 The vessels have been injected in certain situations with mercury, by 

 simply puncturing with a fine-pointed canula the parts in which the 

 plexus is supposed to exist, and allowing the liquid to diffuse itself 

 gently. Following the course of the vessels, the injection passes into 

 the larger trunks and thence to the lymphatic glands. The regularity 

 of the plexus through which the liquid is first diffused and the passage 

 of the injection through the larger vessels to the glands are proof that 

 the lymphatics have been penetrated and that the appearances observed 



