and some other Animal Fluids. 18f 



monstrating the non-existence of iron as the colouring 

 principle of the blood, for the compounds of that metal 

 convert the red madder to gray and black. 



Whilse engaged in examining the colouring matter of 

 the blood, I received from Mr. William Money, house sur- 

 geon to the general hospital at Northampton, some men- 

 3truous discharge, collected from a woman with prolapsus 

 uteri, and consequently perfectly free from admixture of 

 other secretions. It had the properties of a vtry concen- 

 trated solution of the colouring matter of the blood in a 

 diluted serum, and afforded an excellent opportunity of 

 corroborating the facts respecting this principle, which, 

 have been detailed in the preceding pages. Although I 

 could detect no traces of iron, by the usual modes of 

 analysis, minute portions of that metal may and probably 

 do exist in it, as well as in the other animal fluids which 

 I have examined ; but the abundance of colouring matter 

 in this secretion should have afforded a proportional quan- 

 tity of iron, did any connection exist between them. It 

 has been observed that the artificial solutions of the co- 

 louring matter of the blood invariably exhibit a green tint 

 when viewed by transmitted light: this peculiarity is re- 

 markably distinct in the menstruous discharge *. 



I hope that some of the facts furnished by the above ex- 

 periments may prove useful to the physiological inquirer: 

 they account for the rapid reproduction of perfect blood 

 after very copious bleedings, which is quite inexplicable upon 

 that hypothesis which regards iron as the colouring matter, 

 and may perhaps lead to the solution of some hitherto un- 

 explained phaenomena connected with the function of re- 

 spiration. There can, I think, be little doubt that the 

 formation of the colouring matter of the blood is connected 

 with the removal of a portion of carbon and hydrogen from 

 that ,'uid, and that its various tints are dependent upon 

 such modifications of animal matter, and not, as some have 

 assumed, upon the rllfferent states of oxidizemeut of the 

 iron which it has been supposed to contain. ■ 



* I could discover no globules in this fluid; and although a very slight 

 degree c.f putrefaction liad commenced in it, yet the globules observed ia 

 the blood would not have becu destroyed by so tritiing a change. 



XXXV. On 



