264 BOGERT— CARBON COMPOUNDS. [April 20. 



' marks the passing of the old Vitalistic doctrine, and before we lose 

 sight of it altogether, it may not be amiss to quote some interesting 

 passages from Meldola's recent work on the " Chemical Synthesis 

 of Vital Products." He says, among other things, that while it is 

 quite true that we can produce in the laboratory substances identical 

 with those formed in the living organism, in the majority of cases 

 we cannot maintain that the syntheses are identical in their mechan- 

 ism, and those who would " explain " the biochemical processes by 

 a simple chemical equation should bear in mind the fact that " the 

 sign connecting the two sides of the equation stands for the whole 

 unexplored region of biochemical transmutations." We lack exact 

 knowledge of the nature of the synthetic processes going on in the 

 living organism, and there is little reason for believing that they have 

 much analogy with our laboratory methods. In fact, we cannot 

 duplicate in the laboratory the most fundamental of all these syn- 

 theses — the photosynthesis accomplished by plants, in which carbon 

 dioxide is absorbed by an organic compound and the product decom- 

 posed with liberation of oxygen. While the author does not at all 

 array himself on the side of the vitalists, he concludes, from the 

 summary of experimental results recorded in his book, 



"that the testimony of pure chemistry cannot, as it stands at present (/. e., 

 about 1904), be legitimately interpreted into a direct negation of Vitalism in 

 any form. This negation may, and probably will be made possible in the 

 future, when our chemical methods have been made to approximate more 

 closely to the vital methods." 



Until about the year 1830, it was supposed that the same ele- 

 ment could present itself in only one form, endowed with one in- 

 variable set of properties, and that from the combination of the 

 same elements in the same proportions, only one and the same 

 substance could possibly result. The discovery of isomeric com- 

 pounds, consequently, led to a more careful search for the cause 

 of the difference in the properties of substances with the same per- 

 centage composition. With the establishment of the correct rela- 

 tions of atom, molecule and equivalent, the way was opened for the 

 valence hypothesis, and in 1858 Kekule said: 



" I do not regard it as the chief aim of our time to detect atomic groups 

 which, owing to certain properties, may be considered radicals, and thus to 



