182 TIIK AMI'.UK'AN MONTHLY |.Tu1y, 



Ourinjj th«' m-riod of his oomn'ction with the siiuinarv as 

 principal anl vice principal, upwards of three th()U-;antl slu- 

 (U'Uti! wcri' admitted. 



The study of natural history was his favorite pursuit. 

 from early boyhood, and atVorded him enjoynuMit and recreation 

 wiuMi he was not too hard [tressed with ollicial duties. Hnto- 

 molopy ocoupieci many a leisure hour, hut in later years his at- 

 tention wasdirected morce.Kclusively to l)otany,|)riui;irily tothe 

 phae>H)^amous plants and then to several hranehes of cryp- 

 t()cams, especially to the -U«.>*r/ fu'])ntlric anil the Fri'sh-Water 

 Al.uae of the I'nited .States. In 1.S84, his first volume made its 

 apj)eanince from the Moravian Puhlication concern, in a hand - 

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

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

 three colored plates. The illustrations were photo-litho<;raphs 

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



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

 "The Fresh-Water Alj^ae of the Uniteil States,"' conii)letuental to 

 "Desmids of the United States." one volume containinj^ the text, 

 and the other the iliustrat'ons, with 'J.'JOO (i<!;ures, coverin;^ 157 

 colored i)late8. 



In 18'.>0, appeared the volume, " Diatomaceae of North Amer- 

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

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

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

 tion of the"D^^«mids of the United States,'' which he completed 

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

 gave up all study an 1 investigation and died but a few months 

 afterwards. 



The Contractile Vesicle. 



By DR. ALFRED C. STOKES, 

 TRKNTdN, N. .(. 



It is not surprising that the contractile vesicle in certain of 

 the lower niicroscc)j»ic animals shouUl have received the atten- 

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

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

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



