455 



CHAPTER VI. 



ABSORBENT SYSTEM OF H.EMATOCRYA. 



§ 78. All the definite structures of soft parts — acini and 

 simpler gland-follicles, their prolonged outlets or ' ducts,' — com- 

 pacted sheets or strata called ( skin ' and ' membranes,' mucous or 

 serous, — bladders, sinuses, and tubes, arterial or venous, — threads 

 or fibres, muscular, ligamentous, or nervous — are covered, coated, 

 or lined, by a loose or soft elastic substance, which, as it con- 

 nects the better-defined structures together, and fills up their 

 interspaces, is termed e connective tissue ' {tela conjunctiva, tela 

 cellulosa). It is dispersed in irregular plates, with intervals, cells, or 

 ' lacunae,' and the plates consist of delicate and extremely minute 

 fibrils. The intervals contain a fluid called ' serous,' varying 

 in quantity, and also in quality, according to circumstances : 

 and they intercommunicate freely. These cavities are the seat 

 of a transudation from ' vessels ' and other more definite fluid- 

 holding structures during life : and reciprocally the ' serosity ' is 

 resumed by the beginnings or pores of sinuses and canals. 



The serosity of the cavities of the connective tissue usually 

 consists of — 



Water 975-20 



Albumen 5 - 42 



Extractive matters and fat 07 6 



Mixed salts 15-62 ' 



But it is subject to varieties from many causes, mechanical and 

 chemical, operating both within and out of the body. 



The vessels or canals which seem to be most closely connected 

 with, or to be most directly traceable from, the connective 

 tissue and its lacunae are those called lymphatics, lacteals, and 

 absorbent vessels. This system exists as a separate organic 

 vascular apparatus only in the Vertebrate subkingdom : it was 

 first observed in Mammalia, 2 was discovered by John Hunter in 



1 CCLIT. 



2 In the dog, by Aselli, in 1622 : at least the part of the absorbent system called 

 ' lacteals,' in the mesentery of the animal, ccliii. 



