416 Observations on Organic Chemistry 



much I consider as certain, that the way which has been hitherto pur- 

 sued fritters away our energies without producing any real advantage." 



If this expression of my sentiments at that time be compared with 

 my former or subsequent labours, and be taken in connection with the 

 mass of valuable investigations, conducted by talented and skilful 

 young chemists, at my instigation and under my observation, — investi- 

 gations which embrace every constituent of the animal and vegetable 

 kindoms, and form a great part of all we know thereof— every one, 

 whether favourable or opposed to my views, will confess that all these 

 labours have a common centre — that they are links of one and the same 

 chain. The labours of Demarcay, on the nature of bile ; the important 

 investigations of fatty substances by Redtenbacher, Bromeis, Varentrapp, 

 Meyer ; of the constituents of blood and milk, by Jul. Vogel, Scherer, 

 Jones, Rochleder, and of so many others, — what purpose can reason- 

 ably be assigned to them, except the practical confirmation of those prin- 

 ciples upon which I proceeded at the very outset of my career, and 

 which I developed ten years ago in the clearest manner possible, and to 

 which I adhere now with the same conviction as formerly. 



If my object had not been the attainment of truth, but merely the ac- 

 quisition of some specious aud futile arguments, I might, with regard to 

 the investigation of the nature and constitution of bile, have rested sa- 

 tisfied with Demarcay 's figures ; but I subsequently induced Kemp to un- 

 dertake the same investigation, and after him Theyer and Schloser. These 

 latter gentlemen, after a laborious investigation, which lasted for years, 

 arrived at last at a knowledge of the true nature and constitution of 

 bile, and were enabled to prove that the composition of the bile is not 

 perpetually changing, as was previously supposed, and therefore that 

 the gall-bladder is not like a common sewer, into which all the waste 

 matters of the body indiscriminately flow. In this manner every indivi- 

 dual fact was treated, and all its points fully ascertained and determined. 



And now, after eighteen years of incessant labour, and after the ap- 

 plication of the intellectual energies of so many individuals, when I ven- 

 ture to sum up our results, and to deduce such inferences and conclusions 

 as legitimately flow from them, there comes a man — my friend — of the 

 highest authority in science, and dares to brand the intellectual expres- 

 sion of all these labours as a mere play of fancy ! He calls our results 

 " probability-theories," and this simply, and for no better reason, than 

 because we take the heart for a pressure and suction-pump, in the sense 

 as the eye, for instance, is compared to a camera obscura, — because, 

 by a mere error of the press, it is stated in my work, in one single place, 

 that the urine is secreted from venous blood, — because we believe arte- 



