PIONEERS OF SCIENCE IN AMERICA 313 



eralogy was extensive and accurate and at his ready command. Farm- 

 ers and horticulturists came to him and learned how to check the 

 ravages of destructive insects; physicians sent rare or new human 

 parasites and were told their nature and habits and the best means 

 of prevention; jewelers brought rare gems and learned their value. 

 His comments, at the academy, on the recent additions to its collec- 

 tions, gave a most impressive illustration of his ready command of his 

 vast store of natural knowledge. 



Leidy wrote no books, in the popular meaning of the word. He 

 undertook the solution of no fundamental problem of biology. There 

 are few among his six hundred publications that would attract un- 

 scientific readers, or afford a paragraph for a newspaper. They are 

 simple and lucid and to the point. Most of them are short, although 

 he wrote several more exhaustive monographs. They cover a wide 

 field, but most of them fall into a few groups. Many deal with the 

 parasites of mammals — among them, one in which his discovery of 

 Trichena in pork is recorded. 



Two hundred and sixteen, or about a third of his publications, 

 are on the extinct vertebrates of North America. His first paper on 

 paleontology was published in 1846, and his last in 1888, as the sub- 

 ject occupied him for more than forty years. He laid, with the hand 

 of master, the foundation for the paleontology of the reptiles and 

 mammals of North America, and we know what a wonderful and in- 

 structive and world-renowned superstructure his successors have reared 

 upon his foundation. It was this work that established his fame 

 and brought him honors and rewards. They who hold it to be his 

 best title to be enrolled among the pioneers of science in America 

 are in the right in so far as the founder of a great department of 

 knowledge is most deserving of commemoration; but I do not believe 

 it was his most characteristic work. 



I can mention but one of the results of his study of American 

 fossils. He showed, in 1846, that this continent is the ancestral home 

 of the horse, and he sketched, soon after, the outline of the story of 

 its evolution which later workers have made so familiar. 



More than half his papers are on a subject which seems to me 

 to contain the lesson of his life. Like Gilbert White, he was a home- 

 naturalist, devoted to the study of the natural objects that he found 

 within walking-distance of his home, but he penetrated far deeper 

 into the secrets of the living world about him than White did, find- 

 ing new wonders in the simplest living being. In the intestine of the 

 cockroach and in that of the white ant, he found wonderful forests of 

 microscopic plants that were new to science, inhabited by minute 

 animals of many new and strange forms. His beautifully illustrated 

 memoir on A Flora and Fauna within Living Animals is one of the 



