226 THE HISTORY OF SCIENCE 



Pasteur's preventive inoculation for anthrax was 

 tested under dramatic circumstances at Melun in 

 June, 1881. Sixty sheep and a number of cows were 

 subjected to experiment. None of the sheep that had 

 been given the preventive treatment died from the 

 crucial inoculation ; while all those succumbed which 

 had not received previous treatment. The test for the 

 cows was likewise successful. Pasteur thought that 

 in places where sheep dead of anthrax had been buried, 

 the microbes were brought to the surface in the cast- 

 ings of earthworms. Hence he issued certain direc- 

 tions to prevent the transmission of the disease. He 

 also aided agriculture by discovering a vaccine for 

 swine plague. 



When Pasteur at the age of fifteen was in Paris, 

 overcome with homesickness, he had exclaimed, "If 

 I could only get a whiff of the old tannery yard, 

 I feel I should be cured." Certainly every time he 

 came in contact with the industries silk, wine, beer, 

 wool his scientific insight, Antaeus-like, seemed to 

 revive. All his life he had preached the doctrine of 

 interchange of service between theory and practice, 

 science and the occupations. What he did is more 

 eloquent than words. His theory of molecular dis- 

 symmetry, that the atoms in a molecule may be ar- 

 ranged in left-hand and right-hand spirals or other 

 tridimensional figures corresponding to asymmetrical 

 crystals, touches the abstruse question of the consti- 

 tution of matter. His preventive treatment breathes 

 new life into the old dictum similia similibus cu- 

 rantur. The view he adopted of the gradual trans- 

 formation of species offers a new interpretation of the 

 speculations of philosophy in reference to being and 



