ITS CHEMICAL CONSTITUENTS. 287 



chlorate, have also been supposed to occur in the chyle ; we would 

 here simply refer to vol. i., p. 45 2, where the reasons are given 

 which have led to the adoption of this erroneous view. The 

 efflorescent appearance of the chlorides of sodium and potassium, 

 as seen under the microscope on examining the evaporated 

 spirituous extract, has led to their being mistaken for hydrochlo- 

 rate of ammonia ; but if such appearances were due to the latter 

 substance, there would be no crystals of phosphate of soda, but 

 simply the very easily recognisable crystals of phosphate of am- 

 monia and soda. Moreover, bichloride of platinum precipitates the 

 potassium-compound, but not the ammonium-compound, from the 

 spirituous solution. We have, further, explained in vol. i., p. 

 160, that the occurrence of the octohedral and tetrahedral forms in 

 which the chloride of sodium is so frequently observed under the 

 microscope in evaporated animal fluids, and frequently also in 

 the chyle, is no evidence of the presence of urea. 



It is very difficult to determine whether or not the serum of 

 the chyle is free from iron, like that of the blood ; Reuss and 

 Emmert,* Vauquelin,f Rees,{ and Simon, believe that they have 

 ascertained the presence of iron in the serum of the chyle, and they 

 regard it as more loosely combined than in the blood, that is to say, 

 they suppose that it is united with phosphoric acid or other sub- 

 stances which do not impede the ordinary reactions of the salts of 

 iron. We do not, however, consider ourselves justified in concluding 

 from our own observations, or from those of the above-named 

 chemists, that the serum of the chyle contains iron, because, as it 

 can never be obtained perfectly free from coloured, or at all events 

 colourless cells, the iron that is found may very probably belong to 

 these cells. No one, indeed, would maintain that there is an entire 

 absence of iron in the serum of the chyle, any more than in that 

 of the blood ; for the iron must necessarily pass from the plasma 

 of the chyle into the cells, returning in the blood to the inter- 

 cellular fluid from the cells which are undergoing the process of 

 destruction : but the iron does not appear to constitute an 

 integral constituent of either fluid. 



Little remains to be noticed in reference to the method of 

 analysis to be pursued in the quantitative investigation of the 

 chyle, after the remarks we have already made in treating of the 

 analysis of the blood and of the animal juices generally. It will 



* Reil's Arch. Bd. 8, S. 147218. 



t Ann. du Museum nation, d'hist. nat. T. 18, p. 240. 



$ London Medical Gazette, Jan. 1841. 



