LETTERS. 601 



which we observe in the conjunction between the ureters and 

 the bladder, and of the biliary duct with the duodenum. 

 The ureters insinuate themselves obliquely and tortuously be- 

 tween the coats of the bladder, without anything in the nature 

 of an anastomosis, yet in such a manner as occasionally affords 

 a passage to blood, to pus, and to calculi ; it is easy, moreover, 

 to fill the bladder through them with air or water ; but by no 

 effort can you force anything from the bladder into them. I 

 care not, however, to make any question here of the etymo- 

 logy of words ; for I am not of opinion that it is the province 

 of philosophy to infer aught as to the works of nature from 

 the signification of words, or to cite anatomical disquisitions 

 before the grammatical tribunal. Our business is not so much 

 to inquire what a word properly signifies, as how it is com- 

 monly understood ; for use and wont, as in so many other 

 matters, are greatly to be considered in the interpretation of 

 words. It seems to me, therefore, that we are to take especial 

 care not to employ any unusual words, or any common ones 

 already familiarly used, in a sense which is not in accordance 

 with the meaning we purpose to attach to them. You indeed 

 counsel well when you say, " only make sure of the thing, call 

 it what you will." But when we discover that a thing has 

 hitherto been indifferently or incorrectly explained (as the 

 sequel will show it to have been in the present case), I do not 

 think that the old appellation can ever be well applied to the 

 new fact ; by using the old term you are apt to mislead where 

 you desire to instruct. I acknowledge, then, a transit of the 

 blood from the arteries, into the veins, and that occasionally 

 immediate, without any intervention of soft parts ; but it does 

 not take place in the manner hitherto believed, and as you 

 yourself would have it, where you say that anastomoses, cor- 

 rectly speaking, rather than an anastomosis, were required, 

 namely, that the vessels may be open on either hand, and give 

 free passage to the blood hither and thither. And hence it comes 

 that you fail in the right solution of the .question, when you 

 ask how it happens that with the arteries as patent or per- 

 vious as the veins, the blood nevertheless flows only from the 

 former into the latter, never from the latter into the former ? 

 For what you say of the impulse of the blood through the 

 arteries does not fully solve the difficulty in the present in- 



