558 THE HISTORY OF BIOLOGY 



and which jointly contribute to the existence of the whole, the Fungi by 

 forming the substratum, the Algx by assimilating carbonic acid with their 

 chlorophyll. This discovery, which upon publication aroused the keen op- 

 position of the lichen-systematists, has gradually received confirmation and 

 is now universally accepted as correct. 



Among those who, as far as the vegetable kingdom is concerned, paved 

 the way for a uniform conception of its vital manifestations, must also be 

 mentioned Wilhelm Hofmeister (182.4-77). Born in Leipzig, he was edu- 

 cated with a view to taking up a commercial career and became a music- 

 seller in his native town, but he spent his spare time studying botany, and 

 eventually became a professor, first at Heidelberg and then at Tubingen. His 

 great achievement is his comparative investigations into the reproduction 

 of plants, which he carried out while he was still a music-dealer and which 

 resulted in his being appointed professor. He closely studied the phanero- 

 gams, as well as vascular cryptogams and mosses, especially observing their 

 formation, development, and combination of the sexual products, and he 

 established in all these phenomena a bond of agreement that made possible 

 in all essential respects the adoption of a uniform conception of sexual re- 

 production throughout the vegetable kingdom — an achievement that is 

 all the more remarkable, seeing that his knowledge of the cell was not in 

 advance of the stage at which his own period had arrived. Hofmeister's 

 work on the reproduction of plants was followed up by several later natu- 

 ralists. Among these may be mentioned Nathanael Pringsheim (1813-94), 

 at one time professor at Jena and then a private scholar in Berlin. He found 

 out the method of reproduction of the Algas and published several valuable 

 works on plant physiology. Also, Heinrich Anton de Bary (1831-80), 

 professor at Strassburg, who discovered the sexual reproduction of the Fungi 

 and the alternation of generation in the rust fungi, and also solved a 

 large number of important problems in the sphere of mycology and 

 bacteriology. 



Considerations of space forbid our continuing the account of the develop- 

 ment of plant morphology up to modern times; in fact, all the details will 

 be found in the text-books on the subject. We shall therefore proceed to 

 another branch of biological research, which has also played an important 

 part in modern times. 



5. Geographical Biology 



In the foregoing, Humboldt and Wallace have been named as founders, in the 

 modern sense, of vegetable and animal geography. Like all other branches 

 of biology, these fields of research have in our day become highly specialized. 



