ANATOMY OF. THE LACTEAL AND LYMPHATIC SYSTEM. 433 



rian mucous membrane, and the conjunctiva. When an in- 

 jection has appeared to penetrate in these situations, it was 

 probably a mere infiltration of the parts, as the fluids never 

 have been made to enter the larger vessels, much less pass to 

 a lymphatic gland. 1 



In the visceral layer of the serous membranes, the lym- 

 phatics have been demonstrated in great abundance ; but here 

 they are supposed by Sappey to be derived from the organs 

 to which these membranes are adherent. Their existence in 

 the parietal portion of the membranes is doubtful ; and if 

 they exist here at all, their number is not great. Their ex- 

 istence in the synovial membranes is doubtful. 



Lymphatics have been demonstrated as taking their origin 

 in the voluntary muscles, the diaphragm, the heart, and the 

 non-striated muscular coats of the hollow viscera, though 

 their investigation in these situations is exceedingly diffi- 

 cult. 



Lymphatics are found coming from the lungs in immense 

 numbers. These arise in the walls of the air-cells, and sur- 

 round each pulmonary lobule with a close plexus. The deep 

 vessels follow the course of the bronchial tubes, passing 

 through the bronchial glands and the glands at the bifurca- 

 tion of the trachea, to empty into the thoracic duct and the 

 great lymphatic duct of the right side. 



In the glandular system, including the ductless glands, 

 and in the ovaries, the lymphatic vessels are, as a rule, more 

 abundant than in any other parts of the body. They are 

 especially numerous in the testicle, the ovary, the liver, and 

 the kidney. 



In the substance of the brain and spinal cord, Robin has 

 lately demonstrated a curious system of vessels which entirely 

 surround the capillary blood-vessels, and are connected with 

 the lymphatic trunks or reservoirs described by Fohmann 

 under the pia mater. The capillary blood-vessels thus float 

 in a fluid contained in these cylindrical sheaths, which 



1 SAPPEY, op. cit., tome i., p. 595. 

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