CHAP, i.] TISSUES AND MECHANISMS OF DIGESTION. 511 



the spaces into the lymph-capillary. It is of course possible that 

 the lymph transudes from the lymph- space into the lymph- 

 capillary through the continuous sheet of epithelioid plates, in 

 the same manner that it transudes from the blood-capillary into 

 the lymph-space through the similarly continuous wall of the 

 capillary ; but there are some reasons for thinking that, at places, 

 the epithelioid lining of a lymphatic capillary may be imperfect 

 and so allow the interior of the lymph-capillary to open out 

 into a connective-tissue space. 



It will be remembered that, in the case of some of these spaces, 

 a connective-tissue corpuscle may be found lying on the face of, or 

 partly imbedded in, one of the bundles which form the walls of the 

 space ; and in some cases the space appears as it were imperfectly 

 lined with scattered flat cells, which may perhaps be regarded as 

 transitional forms between an ordinary branched connective-tissue 

 corpuscle and a sinuous epithelioid plate. We may perhaps 

 regard the epithelioid plate as a differentiated connective-tissue 

 corpuscle, whose sinuosities of outline are the remains of its 

 previously branched condition. If this be so we may consider 

 the lymph-capillary as a differentiated connective-tissue space, 

 and consequently may fairly expect that the one, if it does not 

 as suggested actually open into, should be at all events in easy 

 communication with the other. We seem justified at least in 

 concluding that the completely lined lymph-capillaries draw their 

 supply of lymph from the incompletely lined connective-tissue 

 spaces. 



We may probably go a step still further. Many of the con- 

 nective-tissue corpuscles are imbedded in, lie in cavities excavated 

 out of, the cement substance which unites the fibrillse into bundles 

 and sometimes joins the bundles together ; in some situations the 

 corpuscles are similarly imbedded in a homogeneous ground sub- 

 stance which has not become differentiated into fibrillse. The 

 cavities in which these corpuscles lie are, like the corpuscles them- 

 selves, branched and generally flattened ; they appear moreover to 

 be generally larger than the corpuscles so as to leave a small space 

 which can be occupied by fluid. Where two corpuscles lie near 

 each other their spaces may, by means of the branches, communi- 

 cate ; and in some situations, as in the body of the cornea where a 

 number of flattened corpuscles are imbedded in the lamina of 

 ground substance which unites each two adjacent parallel (or 

 rather concentric) laminae of fibrillated bundles, the series of 

 cavities, uniting by their branches may be regarded as con- 

 stituting a labyrinth of passages, largely but not entirely filled by 

 the corpuscles, space being left for some amount of fluid. That 

 fluid we need hardly say is lymph. And though the view is not 

 one admitted on all hands, there are reasons of some weight for 

 thinking that these cavities belonging to the corpuscles open out 

 into the connective-tissue spaces just treated of or even more 



