182 THE AMERICAN MONTHLY [July, 



During the period of his connection with the seminary as 

 principal and vice principal, upwards of three thousand stu- 

 dents were admitted. 



The study of natural history was his favorite pursuit 

 from early boyhood, and afforded him enjoyment and recreation 

 when he was not too hard pressed with official duties. Ento- 

 mology occupied many a leisure hour, but in later years his at- 

 tention was directed more exclusively to botany, primarily to the 

 phaenogamous plants and then to several branches of cryp- 

 togams, especially to the Musci hepaticse and the Fresh-Water 

 Algae of the United States. In 1884, his first volume made its 

 appearance from the Moravian Pablication concern, in a hand- 

 some royal octavo volume, " Desmids of the United States and 

 list of Pedi (Strums, " with eleven hundred illustrations on fifty- 

 three colored plates. The illustrations were photo-lithographs 

 from India ink sketches, the work of his own hands. 



This volume was followed, ia 1887, by two more volumes: 

 "The Fresh-Water Algae of the United State-5,"cotnplemental to 

 "Desmids of the United States," one volume containing the text, 

 and the other the illustrations, with 2300 figures, covering 157 

 colored plates. 



In 1890, appeared the volume, " Diatomaceae of North Amer- 

 ica," illustrated with twenty-three hundred figures from his 

 own drawings on one hundred and twelve plates. His botan- 

 ical and literary work ended with the " new and enlarged " edi- 

 tion ofthe"Desmids of the United States," which he completed 

 in the summer of 1892. His health gradually failing, he then 

 gave up all study and investigation and died but a few months 

 afterwards. 



The Contractile Vesicle. 



By DR. ALFRED C. STOKES, 

 TRENTON, N. J. 



It is not surprising that the contractile vesicle in certain of 

 the lower microscopic animals should have received the atten- 

 tion which has been bestowed upon it. The organ is usually 

 conspicuous, and the microscopist's interest is sure to be excited 

 by it, and his imagination set to work to account for its action 



