The History of Biology 385 



animals, and these he could not account for; so his experiment, while a 

 classic, did not settle the problem for others any more than it did for 

 himself. The settling of this vexed question was left for Louis Pasteur 

 (1822-1895), who first showed that decay was not the cause of micro- 

 organisms but the result of them. His experiments were made while 

 working on fermentation problems, and it is from his work that all 

 modern medicine dates, for he was the founder of the science of 

 bacteriology. 



In genetics or inheritance, from a purely biological angle, August 

 Weismann's (1834-1914) work, The Germ Plasm, stands out promi- 

 nently. It was Weismann who called attention to the fact that the 

 bodily characteristics of any individual have but little, if any, effect on 

 succeeding generations. He held that germ-plasm alone carries inher- 

 itance. In other words, that acquired characteristics are not likely to be 

 inherited, and that, if we are to make any change in future generations, 

 we must first learn how to make a change in the germ-cells. 



Francis Galton (1822-1911) gathered a great quantity of statistics 

 on the stature of parents and children and published the result of his 

 research in the eighties. 



The most important name in the study of inheritance is that of the 

 Augustinian monk, Johann Gregor Mendel (1822-1884), who combined 

 experimental breeding of plants with a thoroughly scientific philosophy, 

 and evolved from this combination the Mendelian laws which are now 

 used wherever breeding experiments are performed, whether on plants 

 or animals. 



In the field of organic evolution, one may find among the ancients 

 many thoughts which show conclusively that they were not unaware of 

 a gradual change from smaller beginnings to greater and more developed 

 products. Thus St. Augustine (died 604) calls attention to the fact 

 that a God is the greater, the more potentialities he can enclose within 

 a smaller area, which potentialities can then unfold and evolve. 



Among the moderns, Buffon (1707-1778), was the first to obtain a 

 clear inkling of geographical isolation, struggle for existence, and arti- 

 ficial and natural selection, and he propounded a theory of how varia- 

 tions came about through environment. 



Erasmus Darwin (1731-1802) wrote on changes going on in the 

 animal world and embodied his ideas in verse. 



Lamarck (1744-1829) is the most philosophical, which means the 

 most profound, of all the writers of the evolutionary school, as he 

 actually tried to explain WHY changes took place in the organic world. 



Cuvier (1769-1832), who was a contemporary of Lamarck, and who 

 at that time held the highest attainable place in the zoological world, 

 was a consistent opponent of Lamarck, but Geoffroy Saint-Hilaire (1772- 

 1844), though never attaining the rank of Lamarck, was a staunch up- 



