Decembee 13, 1907] 



SCIENCE 



813 



and leisure to investigate, Dr. Leidy began 

 that series of brilliant researches which 

 made him, during a period of forty years, 

 the most conspicuous ornament of the uni- 

 versity and Academy of Natural Sciences, 

 and that at a time when Cope, Meehan, 

 Eedfield, Cassin, LeConte, Horn, Tryon and 

 Allen were among the active members at 

 the regular Tuesday meetings of the acad- 

 emy—a galaxy of talent truly. Leidy 's re- 

 searches, communicated principally to the 

 academy, and published in its Journal and 

 Proceedings, embracing all branches of 

 natural history and numbering over 550 

 contributions to our knowledge of nature, 

 attracted the attention of this country, 

 Europe and indeed of the whole world. 

 Dr. Leidy 's familiarity with all natural 

 objects invariably impressed those brought 

 in contact with him. If some minute in- 

 fusorian was shown under the microscope, 

 one would have supposed from his observa- 

 tion that he had devoted his life to the 

 study of the Protozoa. A worm being sub- 

 mitted to him for identification his descrip- 

 tion of its structure would lead to the infer- 

 ence that his specialty was helminthology. 

 One had only to see Dr. Leidy dissect a fly 

 or a snail no bigger than a pin's head to 

 realize that he was an admirable compara- 

 tive anatomist. His drawings of the struc- 

 ture of insects and moUusks are made use of 

 even at the present day by recent authori- 

 ties to illustrate their text-books on ento- 

 mology and eonchology. While Dr. Leidy 

 made no claim to being an authority on 

 mineralogy, mineralogists consulted him in 

 connection with their specialty, prominent 

 jewelers in regard to the value of diamonds 

 and other gems. As an illustration of the 

 accuracy of his knowledge in this respect, 

 it may be mentioned that on one occasion, 

 when visiting the Centennial, Dr. Leidy 

 recognized in one of the exhibits a mineral 

 labeled beryl as being really topaz, and of 

 great value. On careful examination by 



experts it was shown to be topaz and sub- 

 sequently the specimen was sold for many 

 thousand dollars. The speaker can testify 

 as to his knowledge of botany, having ac- 

 companied him on a trip through the Rocky 

 Mountains in company with one of the most 

 critical of botanists, who was amazed at 

 Dr. Leidy 's familiarity with the western 

 flora. He rarely if ever was at fault; if, 

 however, he failed to identify a species cor- 

 rectly, with his characteristic honesty he 

 was the first to acknowledge it. Of the 

 innumerable streams and ponds in the 

 neighborhood of Philadelphia visited in 

 company with Dr. Leidy with the object 

 of obtaining infusoria, etc., the speaker can 

 not recall a single instance in which Dr. 

 Leidy did not at once recognize the objects 

 when viewed afterwards under the micro- 

 scope. His work on the Rhizopoda is a 

 monument to his skill as a microseopist. 

 Some years ago the theory was advanced 

 that catarrh and hay fever were produced 

 by an infiisorian animalcule, the Asthmatos 

 ciliaris. Dr. Leidy having been requested 

 to express an opinion in regard to the na- 

 ture of the supposed infusorian at once 

 recognized through his familiarity with 

 this class of animals that the so-called in- 

 fusorian animalculffi supposed to be the 

 cause of disease were only "incomplete, 

 deformed ciliated epithelial cells. It never 

 crossed my mind that they were anything 

 else than ciliated epithelial cells more or 

 less modified by the condition of the catar- 

 rhal affection."- Leidy 's discovery of the 

 Trichina in the pig, explaining how man 

 comes to be infested with that parasite and 

 whereby thov;sands of lives have been saved, 

 would alone have entitled him to recogni- 

 tion as one of the foremost helminthologists 

 of the day— and which indeed he was 

 considered. As is well known, Leidy was 

 the pioneer in American paleontology. 



'American Journal of Medical Sciences, 1879, 

 p. 86. 



