212 On the Operation of Medicines. 



" the fmall guts ; and after three hours opening 

 ** the dog again, I faw many of the ladeals of a 

 " deep blue colour, feveral of them were cut, 

 " and afforded a blue liquor, fome of the decoc- 

 " tion, running forth on the mefentery. After 

 " this I examined the du5lus thoracicus, (on which, 

 " together with other veffels near it, I had on 

 ** my return made a ligature) and faw the recep- 

 " taculum chyliy and that duSfus of a bluifh colour j 

 " not fo blue indeed as the lafteals, from the fo- 

 " lution mixing, in or near the recepiaculum, with 

 " lympba; but much bluer than the du^us ufed 

 ** to be, or than the lymphatics under the liver> 

 ** with which I compared it, were*." 



Stone blue is a preparation of cobalt, pot-afh, 

 and white lead; whicbj ^bein g converted into 

 glafs, is ground into a fine pmvder. And if 

 fuch a fubftance can pervade the la6leals, we 

 may conclude that they are permeable to other 

 bodies, befides thofe defigned for nutrition, and 

 capable of aflimilation with the blood. This ar- 

 gument, from analogy, receives great additional 

 force from the known fa6t that mercury, and 

 various other aftive remedies, may be conveyed 

 into the body through the abforbents of the fkin, 

 a fyftem of veffels, fimilar to thofe above-men- 

 tioned, in their ftrufture, ufes, and termination. 

 In a cafe of hydrocephalus internuSy on which I 



* See Philofoph. Tranf. abridged by Motte, chap. IV. 

 part II. p. 76. 



have 



