202 The Botanical Gazette. [May, 
won most credit in Germany. Further questions as to the 
presence of sexes in lichens, and as to the structure and de- 
velopment of their organs of fructification, have been pursued 
especially by Stahl, FUNFsTUCK (docent in Stuttgart), and G. 
bbe. Alfred Mdller succeeded in Brefeld’s laboratory in 
cultivating lichens saprophytically, and without the alge, in 
nutrient solutions. 
The appearance in 1865 of ‘‘Die Experimentalphysiologie 
der Pflanzen,” by JULIUSSACHs (Freiburg in Baden, Wiirzburg), 
marked an epoch in the development of vegetable physiology. 
The work at once restored vegetable physiology to its place 
at the center of scientific research, whence it had been pushed 
aside by the increased interest in anatomical investigation. 
The work did this the more successfully since it contained not 
merely a clear and well arranged review of the achievements 
of former times, but also the fundamental investigations of 
its author which extended to nearly all of the divisions of 
physiology. The number of physiological researches which 
were then carried on by Sachs himself, and by his pupils, 
grew from year to year, and were for the most part published 
in the Arbeiten des botanischen Instituts zu Wirzburg- 
These researches concerned all divisions of physiology, but 
especially the relations of plants to those external forces 
which operated uponthem. PFEFFER (Basel, Tubingen, Leip- 
zig) developed especially the physical side, and during the 
last twenty years has produced a series of most remarkable 
works. _ His investigations of the chemotactic movements 
awakened special interest, for they explained, at a single 
stroke, as the attraction of definite organisms by chemical 
‘substances, the until then enigmatical influence which the 
sexual products exert, even at a distance, upon each other. 
His ‘‘Handbuch der Pflanzenphysiologie,” which appeared 
in two volumes in 1881, at once became indispensable to 
every botanist. GEORG KLEBs (of Basel) has since then €s- 
pecially developed the physiology of the vegetable cell; pho- 
totactic phenomena were exhaustively studied by Strasburg- 
er and Stahl; W. DETMER (of Jena), and W. Schimper have 
distinguished themselves in the field of physiology of nutri- 
tion, and many valuable contributions to our knowledge of this 
subject have been made by B. FRANK (professor at the Agrl- 
cultural College in Berlin). We are indebted to A. HANSEN 
(of Giessen) for good chemico-physiological contributions, 
