INGEN-HOUSZ 



17 



those who have beat the ground the most, and are consequently the best acquainted 

 with it, weary themselves without starting any game; when it may fall in the way of a 

 mere passenger, so that there is but little room for boasting in the most successful 

 termination of the chase." 



The "mere passenger" 



4. The Importance of Sunlight: Ingen-Housz 



in this case turned out to be the Dutchman, 

 Ingen-Housz. Three years older than Priestley (he was born in 1730 in 

 the Dutch town of Breda), he was a man of the world and until then had 

 found httle time for experimental research. He practiced medicine, first 

 in his home town in Holland, then in England and Austria, where he be- 



^^t 



t 



Fig. 3. — Jan Ingen-Housz (from a bust bj- Seifert). 



came court physician to the Empress Maria Theresa, and was named 

 Aulic counselor of the Empire, in recognition of his services in saving, 

 by inoculation, the children of the Empress during an epidemic of small- 

 pox. According to Ingen-Housz' own story, his interest in the chemical 

 function of plants was aroused by the speech which the then President 



