July i-Sept. 30,1918 
Illustrations 
XI 
Plate 62. Plasmodiophora brassicae: Three clubs, each of which has resulted Pa 8 e 
from the original infection of a small bit of tissue on one side of the stem.. 572 
Plate 63. Plasmodiophora brassicae: Some typical spindle-shaped clubs 
taken from cabbage plants grown in infected soil.,.. 572 
Plate 64. Plasmodiophora brassicae: A.—A longitudinal section through a 
young cabbage stem. Infection has taken place at two points on the stem 
and the swellings are about to fuse together. B.—A longitudinal section 
through a cabbage stem 11 days after inoculation of a Single small spot on 
the stem.. 572 
Plate 65. Plasmodiophora brassicae: A.—A section through a cabbage stem 
13 days after inoculation. B.—A section 15 days after inoculation. 572 
Plate 66. Plasmodiophora brassicae: A.—A section through a cabbage stem 
17 days after inoculation. B.—A section through a stem 19 days after 
inoculation. 572 
Plate 67. Plasmodiophora brassicae: A.—A section through a cabbage stem 
21 days after inoculation. B.—A stage in the infection of the cambium.. 572 
Plate 68. Plasmodiophora brassicae: A-B.—Both figures on this plate show 
cross section through cabbage stems that became infected when rather old. 572 
Plate 69. Plasmodiophora brassicae: A.—A longitudinal section through a 
cabbage stem that became infected after the vascular elements were well 
differentiated. B.—A section through one of the knoblike branch roots 
that are produced on infected roots. 572 
Plate 70. Plasmodiophora brassicae: A.—A portion of a longitudinal section 
through the stem of a young cabbage plant. B.—What is believed to be 
a very early stage of cell-wall penetration. C.—An early stage in passage 
through a cell wall. D.—A little later stage than that shown in C. E, F.— 
Still later stages in the passage through cell walls. G.—Interesting because 
a nucleus is passing through the opening in the wall. H.—A case in which 
the opening made in the cell wall is unusually large. I.—Plasmodium 
passing through the end of a cell in the region of the cambium. J.—A case 
in which plasmolysis of the host cells seems to have broken a migrating 
plasmodium into two parts. K.—An ameba taken from a cambium cell. 
L, M.—Two small plasmodia that were found in cambium cells far from 
the point of original penetration. N.—Infected cambium cell. 572 
Plate 71. Plasmodiophora brassicae: A.—A young shoot arising from a dis¬ 
eased lateral root of cabbage. B.—Two large diseased shoots coming from 
diseased tissue. 572 
Plate 72. Plasmodiophora brassicae: A.—A section through a portion of an 
infected green cabbage leaf. B.—An infected shoot that is growing down¬ 
ward. 572 
Plate 73. Plasmodiophora brassicae: Stages in the infection of medullary 
rays. A.—A rather large woody cylinder that is beginning to split apart 
through the abnormal growth of its medullary rays. B.—The woody 
cylinder of a cabbage root. 372 
Plate 74. Plasmodiophora brassicae: A.—Somewhat later stages of medullary 
growth than those shown in Plate 73. B.—Another cylinder being split 
into two equal halves. 372 
Plate 75. Plasmodiophora brassicae: A.—The wood of an old cabbage stem 
that is being split apart by medullary infection. B.—A somewhat later 
stage... 372 
Plate 76. Plasmodiophora brassicae: A.—A longitudinal section through the 
woody part of a cabbage stem that has been split open by medullary in¬ 
fection. B.—A cross section of a young cabbage root. 372 
