60 Proceedings of the Royal Irish Academy. 



with a speed and skill worthy of a pnpil of Pasteur. After eight weeks the 

 germ had been discovered and isolated, a successful treatment devised, and a 

 scheme of prevention drawn up. Nocard's remedies were adopted by the 

 Department, with the result that calf mortality through white scour was 

 completely overcome. 



There is an old French proverb : " Glory is the sunlight of the dead." 

 It is over twenty-five years now since all Europe laid its wreaths on the grave 

 of Pasteur; but he is living yet, and will continue to live, in the work of the 

 lesser men whom he inspired, " and glory is the least of things that follows 

 this man home." 



2 —LOUIS PASTEUR AS CHEMIST. 



By PROEESSOE SYDNEY YOUNG, D.Sc, F.R.S., President. 



It is unquestionably on account of Pasteur's magnificent services to mankind 

 that his name will be honoured as long as our civilization lasts ; but' even if 

 his only researches had been those on chemistry and fermentation, he would 

 always be counted amongst the greatest men of science of the nineteenth 

 century. 



It was Delafosse, at the Ecole Normale, who first directed Pasteur's 

 attention to crystallography and molecular physics, and after becoming 

 assistant to Balard. Pasteur repeated the work of de la Provostaye on the 

 crystalline form of the tartrates. 



The existence of small facets or hemihedral faces on quartz crystals had 

 previously been noticed by Haiiy, who classified the crystals as right-handed 

 or left-handed, according to the position of the facets. Again, Biot had 

 observed that some quartz crystals turned the plane of polarization of 

 polarized light to the right, others to the left. Finally, Sir John Herschel 

 had suggested a relationship between the two phenomena— a relationship 

 which had been confirmed by experiment. 



Pasteur was the first to observe similar small facets on crystals of tartaric 

 acid and of its salts, and he took up with enthusiasm the study of these 

 crystals. He also prepared and crystallized the sodium-ammonium salt of 

 the optically inactive form of tartaric acid known as racemic acid, and found 

 that the crystals were of two kinds, each with hemihedral faces, and related 

 to each other as an object is to its image in a mirror. The crystals of one 

 kind were identical with those of the sodium-ammonium salt of ordinary, 

 optically active tartaric acid ; the crystals of the other kind had never before 



