THE BOTANISTS OF PHILADELPHIA. 369 



versity Education of Women appointed him lecturer for 

 the year, when his class was attended by sixty-two students. 

 In 1888 he became Principal xA^ssistant in the University, 

 and was thus called on to direct large classes in lecture and 

 laboratory work. He thus acquired exceptional opportuni- 

 ties for familiarizing himself with the work of all depart- 

 ments of a large botanical school, situated in the midst of 

 one of the richest botanic gardens in the world. Teaching 

 in the class-room, research in the laboratory, organization 

 work in the herbarium and museum, or demonstration in 

 the field, filled up the hours of a busy life. 



In the early period of his Edinburgh life he amassed 

 large collections of fossil plants, and published a paper " On 

 Lepidophloios, a Genus of Coal Measure Plants." The fossils 

 he presented to the museum of the botanic garden, where 

 they are now deposited. His studies on cell structure, on 

 pitchered insectivorous plants, on the minute structure of 

 hybrids, on dicotyledonous stems, and many other topics, 

 extended from 1883 to 1891, but are only in part published 

 as yet. 



In 1891 the Research Committee of the Royal Society 

 voted him twenty-live pounds to publish investigations on 

 hybrid plants. His results embodied in the " Transactions 

 of the Royal Society of Edinburgh^'' attracted the attention 

 of biologists to a large and important field for investigation. 

 In the same year he made some remarkable discoveries 

 regarding the sensitive movements of the Venus Fly Trap, 

 which later were laid before the Botanical Section at the 

 Washington meeting of the American Association. The 

 completed research was published a year later in " Contri- 

 butions from the Botanical Laboratory of the University of 

 Pennsylvania. 



