WOEK OF VAN't HOFF BRUNI. Y73 



isomers. "We have thus optically active compounds containing an 

 asymmetric atom of sulphur, selenium, silicon, tin, and lead. Even 

 pentavalent atoms like those of nitrogen and phosphorus may give 

 rise to the formation of stereo-isomers, as Le Bel was the first to 

 show. 



To-da}', after a lapse of 37 years, we can see that few theories have 

 been able to achieve such triumphs. There does not exist to-day a 

 single well-established fact which had not been anticipated, at least 

 in germ, in the memoir of 1874. It would not be out of place to add 

 here a few words with the purpose of examining more closely the 

 intrinsic merit and amount of originality in the work of van't Holf 

 and Le Bel, for it is not unusual to read or to hear rather unsatis- 

 factory statements relative to them. It is said sometimes that the 

 merit of the Dutch scientist consisted in having imagined and intro- 

 duced the tetrahedral model or in having first had the conception 

 of the spacial distribution of atoms in the molecule. Nothing is more 

 erroneous, or at least more superficial, for in this connection van't 

 Hoff and Le Bel had several predecessors. The tetrahedal model 

 was a necessary consequence of the conception of Kelmle, who had 

 used it himself in its present form without, it is true, giving it the 

 wide application which we give it to-day. And, as we have already 

 said, Wislicenus had affirmed in a general way the necessity of having 

 recourse to spacial configurations to explain certain isomerides. 

 Earlier still, in 1869, Paterno had proposed to use for this purpose 

 precisely the tetrahedal arrangement. It is not, then, in this that 

 the merit of van't Hoff lies, but rather in the fact that he was the 

 first to conceive the brilliant idea of the significance of the asym- 

 metric carbon atom, and, also, after attentive and rigorous examina- 

 tion of all the facts already Imown, gave to the theory its definite 

 form, so that one may say that it sprang, like the classic Minerva, 

 already armed from the brain of Jupiter. 



But from 1877 on van't Hoff no longer took a direct and creative 

 part in the further development of the doctrine which he estab- 

 lished. He nevertheless followed it always with an attentive eye 

 and marked its progress in the successive editions of his books, 

 among which we shall mention particularly " Dix annees dans I'his- 

 toire d'une theorie," which offers a fine example of how to triumph 

 with modesty. 



But it is time to return to the year 1877; that is, to the moment 

 when our young hero took up his work at the University of Amster- 

 dam. He had made his debut three years before. He was only 25 

 years of age and had already established a theory which was sufficient 

 to pass his name on to history. All the immense field of chemistry 

 stretched before him ; his eye could not fail to discern in it new paths 

 which were to lead him to still more brilliant triumphs. 



