134 HEROES OF SCIENCE. 



had a very remarkable influence on the mind and 

 emotions of this great investigator. Always 

 religious, he longed more and more for communion 

 with his Maker and the author of all the wonders 

 he .was constantly studying. When in better health 

 he was happy in his thoughts, and considered that 

 it was his duty to study nature ; but when ill, 

 from the effects of overwork, he began to think 

 that his labours were leading him astray, and that 

 to seek the good opinion of his fellow-creatures 

 and to become famous, was a sin. Sometimes he 

 gave up science, to begin again wath fresh zeal, and 

 then he would neglect it, giving up his whole time 

 to religion. Unfortunately he was unreasonable 

 in his method of working. Boerhaave, the great 

 physician, thus wrote of Swammerdam : " He 

 laboured so assiduously at this work as to destroy 

 his constitution, nor did he ever recover a shadow 

 of his former strength. The labour, in fact, was 

 beyond the power of ordinary men — all day he 

 was employed in examining objects, and at night 

 described and delineated what he had seen by day. 

 At six in the morning, in summer, he began to 

 receive sufficient light from the sun to enable him 

 to trace the objects of his examination. He con- 

 tinued dissecting until twelve, with his hat removed 

 lest it should impede the light, and in the full 

 blaze of the sun, the heat of which caused his head 

 to be constantly covered with profuse perspiration. 

 His eyes being constantly exposed to a strong 

 light, the effect of which was increased by the 



