Lecture XII — 165 — Mycotrophic Phagocytosis 



up of living cells of the organism affected. In parasitism, in addition 

 to possible anatomical and cytological damage, a fatal extraction of 

 nutritive material may ensue." 



Older Descriptions of Phagocytosis : — New names do not make 

 new processes, and that of phagocytosis had long been known, although 

 not under that name. Reissek (1847) observed ellipsoid bodies in 

 Neottia that later turned yellow, — in other words, clot-formation; 

 and in Orchis Morio he noted the process was especially active in 

 autumn and early winter. He described and figured peloton forma- 

 tion with remarkable clearness. Schacht (1854) saw that the fungus 

 uses starch in orchid rhizome and root-cells; but Prillieux (1856) 

 differed with Schacht: The 2-3 outermost cortical layers of cells 

 in Neottia were filled, he says, with a yellowish-brown matter which 

 Schacht had considered as an index to death of cell. Prillieux 

 found it in a great number of orchid genera, in cells which retain their 

 nuclei ; but he noted that the matter seemed to diminish in roots which 

 have vegetated a long while, from which he inferred that the brown 

 matter served for nutrition of the plant. The material, he said, is 

 probably nitrogenous. The infected orchid cell nuclei are of great 

 size and often have 2 nucleoli. The cells having brown matter regu- 

 larly contain filaments wound without order about the central mass 

 in each cell. Reinke (1873), noting the matter or "slime" in orchid 

 cells, ingeniously supposed that it is a "Schwellkorper" or apparatus 

 for maintaining sap concentration. 



Phagocytosis in Peloton Mycorrhlzae : — The process of phago- 

 cytosis in the peloton mycorrhizae, found chiefly in orchids, is accord- 

 ingly as follows : Hyphae penetrate in part through root-hairs or in 

 part directly through cell-walls, and enter the cortex, finding entrance 

 through passage cells where an exo-dermis is present. Hyphae pass 

 freely through cell walls, a marked constriction sometimes being 

 evident in the hypha at the point of passage of cell- wall (Dangeard, 

 1898) which grows up about the hypha (Burgeff, 1932) to form a 

 wall-tubule or "Rohrentiipfel." This organ Burgeff considered one 

 which, by differences of suction force, passes water or solutions of 

 low sap concentration through the hypha. Passage of hyphae through 

 cortical cell- walls is sometimes prevented by thickening of the walls 

 to 6 or 7 ji, by undergoing an excessive cuticularization (Burges, 

 1939). 



At a certain distance from the central cylinder, depending on the 

 sort of orchid, the hypha ceases to grow forward and begins to coil. 

 Burgeff (1909) observed coiling on aerial hyphae when a drop of 



