83 



The old Cireek term, parasite, has undergone shifts in meaning 

 since it was coined. Stripped of the connotation, flattery, it 

 gives a graphic picture of the rust fungus which literally sits 

 "beside the food" in the cells of a green plant. The rust fungus 

 will take its food only from a living cell. Therefore rusts may not 

 be grown on dead culture media in the laboratory as are bac- 

 teria. (43) 



In the case of hollyhock rust a special interest attaches to 

 the haustoria. The Swedish botanist, Jakob Eriksson, published 

 studies of rust-infected hollyhock leaves in support of his 

 "Mycoplasm Theory." (26) Eriksson was an authority upon 

 cereal rusts and he formulated, in 1897, the "Mycoplasm 

 Theory" to explain epidemics of grain rusts which he thought 

 the rust spores alone were unable to initiate. (23) He described 

 a formless fungous substance within the substance of the living 

 host cells which he believed was handed on in dormant state 

 from cell to cell of a growing plant, and from plant to seed. He 

 figured these "internal germs" or "corpuscles speciaux" de- 

 veloping into definitely outlined spheres, lengthening into 

 filamentous form within the host cells, penetrating the wall by 

 capillary hyphae, finally developing a wealth of hyphae be- 

 tween the host cells — in short becoming the well known inter- 

 cellular fungus which produces the eruption of spores upon the 

 leaf surfaces. Marshall Ward in 1903 proved by a series of 

 convincing drawings of infected grass tissue that Eriksson had 

 reversed the story of rust development from a spore; that the 

 "corpuscles" in cells of the leaf sections were merely the cut 

 ends of haustoria; that the stalked filaments were not leaving 

 the cells but were haustoria which had entered the cells for 

 absorption purposes. (62) It is hard, however, to convince the 

 originator of the fallacy of a pet theory. In 1904 and 1905 

 Eriksson again figured his "mycoplasm" in elaborate and ac- 

 curate drawings of sections of rusted grain leaves: drawings 

 which need only the addition of arrows of reverse direction to 

 fit the accepted interpretation. (25) In 1911, still in elaboration 

 of his theory, he published the afore-mentioned monograph 

 upon the hollyhock rust; (26) also in 1917 and 1918 he figured 

 the "mycoplasm" in another fungus, mildew of potato. (27) An 

 Englishman again undertook a refutation. In 1920 Bailey 

 chose the mallow rust for culture experiments. He took seeds 



