£4 



rnEMICAL RESEARCHES ON THE ANIMAL FLUIDS. 



Iron in the 

 bluod. 



Examination 

 of the chyle 

 and lywiph. 



Contents of 

 the tlioracic 

 duct Tariable. 



some of the results less decisive than I could have wished, 

 but I trust, that tiie general conclusions to which they lead 

 will be deemed of sufficient importance^ to occupy the time 

 of this body. 



The existence of iron in the blood was fir.-t noticed by 

 Menghini*, and its peculiar red colour has been more re- 

 cently attributed to a combination of that metal with phos- 

 phoric acid by Messrs. Fourcroy and Vauquelinf. The 

 very slight discoloration occasioned by the addition of infu- 

 sion of galls to a solution of the colouring matter, under 

 circumstances most favourable to the action of that delicate 

 test of iron, first led me to doubt the inferences of those 

 able chemists; and subsequent experiments upon the com- 

 binations, to which they aiiude, tended to confirm my sus- 

 picion, and induced me to give up no inconsiderable portion 

 of the time which has elapsed since the last meeting of this 

 Society, to the present investigation. 



An examination of the chyle and of lynTph, in order to 

 compare their composition with that of the blood, formed an 

 important part of this inquiry ; especially as those fluids have 

 not hitherto been submitted to any accurate analysis, on ac- 

 count of the difficulty of procurmg them in sufficient quan-- 

 tities, and in a state of purity. While engaged ui assisting 

 Mr. Home in his physiological researches, several opportu- 

 nities occurred of collecting the contents of the thoracic duct 

 under various circumstances^ and in different animals ; on 

 other occasions Mr. Brodie has kindly furnished me with tjie 

 materials for experiment. 



IL On the Compos'uion of Chyle. 



The contents of the thoracic duct are subject to much va- 

 riation. About four hours after an animal has taken food, 

 provided digestion has not been interrupted, the fluid in the 

 duct may be regarded as pure chyle : it is seen entering by 

 the lacteals in considerable abundance, and is of a uniform 

 whiteness tl.roughout. At longer periods alter a mtal, the 



* Vincentius Mengbinus c!f> Feirearum Particularum Piogressu in 

 Sanguinem. Comment. Acad. Bonon. T. 2, P. 2, page 475. 



t Systemc dcs Coim. Cliym. Vol 8, p. [Vol. 9, p. ] 52. C] 



quantity 



