MINUTE ANATOMY OF THE CAPILLARY LYMPHATICS. 303 



on either side. A similar arrangement of the two sets of ves- 

 sels is strikingly shown in the case of the villi of the small in- 

 testine, in which the proper tissue of the villi forms a peripheric 

 layer traversed by a close network of capillary bloodvessels, 

 whilst the chyle vessel lies quite in the interior, near the axis, 

 and is generally single and unbranched, as in the rabbit, ox, 

 sheep, and man, though occasionally it has been observed to 

 form a set of anastomosing capillaries, as in the dog, sheep, 

 and ox. Again, if the results obtained from the injection of 

 the cutaneous lymphatics by Teichmann, in a case of ele- 

 phantiasis,* be considered to represent the normal distribution 

 of the lymphatics, the capillaries of this system lie exactly in 

 the centre of the papillae of the cutis, whilst the blood capil- 

 laries traverse their periphery. 



At first sight it appears remarkable that the lymphatics 

 should lie so deeply in organs destined for absorption, as, for 

 example, in the villi ; this relation, however, is in itself a suffi- 

 cient indication that the connective and other tissues of the 

 villi play a most important part in the act of intestinal ab- 

 sorption, and that here also the central chyle vessel only acts 

 as an efferent or drainage pipe. The function performed by 

 the roots of plants is probably similar to that of the epithe- 

 lium and the parenchyma of the villi. The chyle vessels, on 

 the other hand, appear to be analogous to the vessels and fibro- 

 vascular tissue of the plant ; if these were able to absorb, a 

 more superficial position would be more appropriate to the 

 discharge of their function. 



Having now learnt the form and arrangement of the 

 capillary lymphatics, we turn to the consideration of their 

 structure, a question which has recently received particular 

 attention, and has met with various answers. Are they, like 

 the bloodvessels, provided with a proper wall, or are they 

 destitute of a limiting membrane, constituting only lacunse, or 

 spaces in the tissues amongst which they lie ? The decision of 

 this question is particularly interesting in the case of the chyle 

 vessels of the villi. The chyle formed after the ingestion of 

 food containing abundance of fat owes its white colour to the 



* Untersuchungen uber das Saugadersystem, Taf. 6, fig. 4. 



