BESSEY: MYCOLOGY 229 



impelled them to tireless research. By his scrupulous exactness of observation 

 and teaching he gave to his students and to the readers of his published works 

 a new appreciation of what fungi were and of their relationships. His first pub- 

 lication, in 1852 on Achhja prolifera, was a result of research carried on during 

 the last months before he took his final medical examinations and received his 

 degree. This paper was followed in 1853 by a 144-page booklet entitled Unter- 

 suchungen iiher die Brandpilze (including at that time the fungi now placed in 

 the orders Ustilaginales, Uredinales, Protomycctales, and Peronosporalcs). Ac- 

 cording to Jost, the chief points demonstrated in this second paper were the 

 presence of a mycelium in all these groups from which, in definite ways, arose 

 the characteristic spores. They were not the products of metamorphosed diseased 

 host tissues. This was at a time when many botanists still had the idea that these 

 fungi were the products of the transformation of the diseased tissues of the 

 hosts. It was not until 1863 that De Bary wrote a paper in which he described 

 the course of development of some Peronosporaceae from the formation of the 

 conidia, their germination upon and infection of the host plants, the progress 

 of the fungus in the host, and the formation of the asexual conidia and of the 

 sexual organs, the oogones and antherids. He found the latter organs also in 

 Eufotium and followed the development of the perithecium and asci and asco- 

 spores. He also demonstrated that the mold laiown as "Aspergillus glaucus" was 

 the asexual phase of Eurotium. 



The slime molds early attracted his attention (1858, 1859, 1862). He studied 

 the growth of the Plasmodium, the formation of the sporangia and spores, the 

 germination of the latter, the formation of the flagellate amoebae, and the origin 

 of the Plasmodium. Because the life history of the vegetative phases of develop- 

 ment was clearly more animal than vegetable, he changed the name of the group 

 from Myxomycetes to Mycetozoa and boldly asserted that they belonged outside 

 the vegetable kingdom and among the Protozoa. They completely lack mycelium 

 and have a long amoeboid (or plasmodial) stage, hence cannot be placed in the 

 fungi. Although later studies have fully confirmed the validity of De Bary's 

 researches on this group, the majority of botanists have obstinately clung to 

 the old idea that the slime molds are plants belonging to the fungi. Probably 

 the zoologists are partly to blame for not welcoming with enthusiasm their trans- 

 fer from the realm of botany to that of zoology. Most zoologists, it is true, accept 

 them as animals, but all the important books on the slime molds treat them as 

 plants. (Lister, 1925; Hagelstein, 1944; Martin, 1949.) 



De Bary now extended his inoculation studies to the rusts (1863, 1865). He 

 inoculated bean plants. {Plmseolus vulgaris L.). He placed the teliospores of 

 Uromyces in drops of water on their leaves, putting a bell-jar over the plant to 

 prevent accidental contamination and to maintain the humidity of the air. The 

 resulting infection showed first spermogonia and then aecia, but not the uredia 

 or telia. When, however, he sowed the aeciospores in a similar manner on the 

 same species of host, he obtained uredia and telia. Thus he proved, what some 

 mycologists had suspected, that all five sorts of spores — sporidia, spermatia, 

 aeciospores, urediospores and teliospores — were successive spore forms of the 

 same rust. He could get no infection by using spermatia and made the suggestion 

 that they were perhaps the male cells which, although still continuing to be 

 formed, had lost their function. It must be remembered that it was not until 



