ARRANGEMENT OF THE LYMPH PATHS. 337 



trary, if the injection is sufficiently fluid, this may be accom- 

 plished with extraordinary facility, especially when the mode 

 of injection by puncture is adopted. In such cases it will be 

 found that the vessels of origin of the vasa efferentia have 

 such a remarkably moniliform character, and communicate so 

 frequently with one another, that they form quite a cavernous 

 structure. The several canals in this cavernous plexus are so 

 short that their union with the lymph paths of the medul- 

 lary substance are far more difficult to recognise than if they 

 were continuous with a few elongated canals. A general view 

 of the relations existing in these parts may be best obtained 

 from injections with solutions of silver (see fig. 63), and from 

 these it can be established that the branches of the plexus, 

 which up to this point have presented an approximatively 

 circular section, suddenly undergo enormous dilatation, and 

 into the lumen of these dilatations the several segments of the 

 medullary substance imbedded in the hilus substance project, 

 whilst the connective tissue walls of the cavernous plexus be- 

 come continuous with the trabeculse of the medullary sub- 

 stance. The indications of an epithelium may be easily traced 

 from the lymphatic tubes to the trabeculse, and may further be 

 followed on them through the medullary substance. But the 

 trabeculse and septa at the periphery of the glands exhibit also, 

 in silvered preparations, the same characteristic indications of 

 an epithelium ; and I have so frequently been able to satisfy 

 myself of the presence of this, that I may venture to say that 

 they are invested by an epithelium throughout the whole 

 gland. The characters of the lymph path at its entrance into 

 and at its exit from the gland are essentially similar. The re- 

 lations of the several parts may be most simply represented by 

 considering a rete mirabile to be introduced between them, the 

 several branches of which suddenly diverge from the extremity 

 of the afferent vessel, and then proceed to divide and sub- 

 divide, becoming consequently more attenuated. These finer 

 branches perforate the intervening layers of tissue in all direc- 

 tions, freely anastomosing with one another, and finally sud- 

 denly reunite in the extremity of the continuous and tubular 

 efferent vessel. The follicular substance is chiefly developed 

 in the dilatations near the point at which the vasa efferentia 



