LYMPHATIC SYSTEM. 191 



been pronounced bags or follicles, are only small vessels clus- 

 tered together or convoluted. And on making a variety of 

 experiments on these other glands, I think it evident in what 

 manner the deception has happened to those ingenious anato- 

 mists ; namely, when the excretory ducts of the breast, for ex- 

 ample, are injected with vermilion and painter's size, the small 

 acini of which that gland consists are made extremely red, 

 and such a preparation being dried, the acini appear as large 

 as pins' heads, so that the breast has been suspected to have 

 follicles of that magnitude ; but on injecting the breast with 

 mercury, which is a brighter substance, and better contrasted 

 to the dried fibres, I have distinguished what in the other pre- 

 paration might be mistaken for a bag, was here evidently no 

 more than the extremity of the excretory duct, terminating in 

 one of these acini, and dividing into a number of branches so 

 suddenly as to come near "to Ruysch's description of the peni- 

 cilli of arteries ; but the small branches, into which this extre- 

 mity of the duct divided, were so close to one another, that in 

 the preparation where they were filled with size and vermilion, 

 they could not be distinguished, but in that where they con- 

 tained mercury, it evidently appeared that in each acinus of the 

 magnitude of a pin's head, there was a considerable number of 

 branches, but so small as not easily to be seen with the 

 naked eye (LXXXVIII). 



The ingenious Lieberkiihn has mentioned another experi- 

 ment, from which he was not only persuaded that the lacteals 

 formed an ampullula upon the villi, but that this ampullula was 

 filled with a spongy substance. This experiment he made by 

 inflating the villi by the arteries and the veins, and upon dry- 



(LXXXVITI.) That the roots of the milk-ducts are little cells or vesi- 

 cles, typifying a like structure in a whole series of glandular organs, is 

 now a well-known fact. Professor Miiller a has noticed the observa- 

 tions made on this subject in the hedgehog, as early as 1751, by 

 Duvernoi. Mr. Cruikshank b proved the existence of this structure 

 in the human breast ; and Mascagni, according to Miiller, observed, 

 in 1819, the absence of any direct communication between the vesicu- 

 lar ends of the milk-tubes and the blood-vessels. Sir Astley Cooper 

 has given an admirable description of the Anatomy of the Human 

 Breast, 4to, London, 1840. 



a On the Structure of the Glands, tr. hy b Anatomy of the Absorbing Vessels, 

 Mr. Solly, p. 9, 8vo, Lond. 1839. p. 209*, 2d edit. 4to, Lond. 1790. 



