CEREBRO-SPINAL LYMPH MECHANISMS 133 



innocuous by the glandular agency of these organs, ere it 

 is permitted to re-enter the blood streams. All this is, no 

 doubt, and may rightly be called highly speculative, but 

 still we hold it to be so strongly reasonable that we have 

 felt constrained to add it to what we have already 

 advanced with regard to the economy of cerebro-spinal 

 fluid excretion, as well as for the purpose of enabling us 

 to assign a living " everyday " working function to two 

 organisms for which anatomists have hitherto failed to 

 find a probable use. These cystiform organs are possessed 

 of the requisite anatomical structure glandular and neuro- 

 muscular to enable them to perform the work of 

 collection, chemico-physiological treatment, and excretion 

 of whatever fluid can reach them along the adventitial 

 envelopes of the two carotids and jugulars, which are 

 necessarily, anatomically, and histologically, continuous 

 through their envelopes with the dura-arachnoid textures; 

 hence, we are strongly of opinion that they perform this 

 function, a function, moreover, very much akin to that 

 which we have assigned to the coccygeal gland ; another 

 organism, furthermore, with which anatomists are accus- 

 tomed to classify them, preparatory to shelving them 

 amongst the quantities " negligible" where in a single 

 sentence they are usually labelled and consigned to rest in 

 oblivion until next " stock-taking." 



We would here reiterate the assertion in this connection, 

 that no " unnecessary structure " can be allowed evolution arily^ 

 so to speak, to be repeated in every generation of the human, 

 or other race, with the attributes of a highly organised texture, 

 without its being called upon to perform a work in consonance 

 with its anatomical character and position to justify its retention 

 and prevent its involution and disappearance. We may thus 

 rest assured that it is altogether unjustifiable to describe 

 any organ, or texture, now surviving in the human body 

 whose function we are ignorant of as a " survival " only, 

 and, therefore, as an encumbrance, which, in these advanced 

 days of evolutionarily determined human destiny, we are 

 warranted, or called upon, voluntarily to neglect, or to 

 sacrifice. 



Therefore, we take it that, if the law of evolution 

 is to be believed, and if it is to have a practical bearing 



