ACKNOWLEDGMENTS. 



The author would express his thanks to his friend Dr. 

 Peter Collier, Professor of Chemistry in the University 

 of Vermont, for a large share of the calculations and re- 

 ductions required for the Tables pp. 150-6. 



Of the illustrations, fig's 3, 4, 5, 7, 47, 63, and 64, were 

 drawn by Mr. Lockwood Sanford, the engraver. For oth- 

 ers, acknowledgments are due to the following authors, 

 from whose works they have been borrowed, viz. : 



SCHLEIDEX. Fig's 10, 13, 17, 19, 30, 48, 49, and 50, 

 Physiologic der Pflanzen und Thiere. 



SACHS. Fig's 56 and 65, Sitzungsberichte der "Wiener 

 Akademie, XXXVII, 1859, and fig's 22, 38, 40, 41, 42, 

 43, 59, 66, 69, 70, and 71, Evperimental-PTiysioloyie der 

 Pflanzen. 



PAYEN. Fig's 11, 12, and 23, Precis de Chimie Lidu*- 

 trielle. 



DUCHAETEE. Fig's 60 and 61, Elements de Botanique. 



Kiinx. Fig's 18, 21a, 29, and 34, Ernahrung des 

 Rindmehes. 



HAETIG. Fig's 20, 21b, 32, EntwicJcelungsgeschichte 

 des Pflanzenkeims. 



UNGEE. Fig. 26, Sitzungsberichte der Wiener Akade- 

 mie, XLIII, and fig. 55, Anat. u. Phys. der Pflanzen. 



SCHACHT. Fig's 33, 37, 44, Anatomie der Gewcechse, 

 fig's 51, 53, 54, and 62, Der Baum, and fig's 52, 57, and 

 58, Die Kartoffel und ihre Krankheiten. 



HENFEEY. Fig's 36 and 39, Jour. Roy. Ag. Soc. of 

 England, Vol. XIX, pp. 483 and 484. 

 7 



