Oct. 1902] 
Notes on Fungi 
159 
center of the cell. A fragment of a cell deprived of its nucleus 
may live for a considerable time and manifest the power of 
coordinated movement without perceptible impairment. Such a 
mass of protoplasm is, however, devoid of the powers of assimi¬ 
lation, growth and repair, and sooner or later dies. In other 
words, those functions that involve constructive metabolism cease 
with its removal. There is, therefore, strong reason to believe, 
that the nucleus plays an essential part in the constructive meta¬ 
bolism of the cell, and through this is especially concerned with 
the formative processes involved in growth and development. 
For these and many other reasons, the nucleus is generally re¬ 
garded as a controlling centre of cell activity.* This activity 
of the nucleus is still further confirmed by a study of the plas- 
modium in question. Before hardening the material in alcohol, 
bit: streaming protoplasm of the myxomycete formed a loose reti¬ 
culum. The main streams of movement were cord-like and in 
places heaped up into considerable masses lying upon the gill 
surface of the mushroom. A section across the gills of the oyster- 
mushroom with the feeding plasmodium upon it shows the strings 
of plasmodial protoplasm in cross section. The protoplasm, when 
stained with iron haematoxylon, is found to be spongy in nature 
with large, open chambers across which run delicate strands of 
plasmic substance. The nuclei vary in such sections of individual 
streams of protoplasm, according to the following count: 175, 45, 
33, 157, 8, 25, 20, 50, 172, made at random. The nuclei are 
dark, and they appear, therefore, as small dark circular grains in 
the faintly stained protoplasm. Their distribution in this protop¬ 
lasm concerns us here. The larger number of nuclei are found in 
close proximity to the gill surface of the mushroon upon which the 
plasmodium is feeding. In some cases, they are so crowded toge¬ 
ther as to appear in the form of an irregular deeply staining mass 
in close contact with the food substance. The distal surface of the 
plasmodium contains few, or no nuclei, and the central body 
of protoplasm quite a number. One, however, is struck by the 
large number of nuclei that lie near the actively digesting lower 
surface. This distribution of the nuclei is of interest in connec¬ 
tion with the statement above that the nucleus controls the con¬ 
structive metabolism of the cell. The digestion of the food pre¬ 
supposes the activity of several ferments. That a process of 
digestion is going on is evident from an inspection of the gill 
surfaces. Here the spores have been removed from their sterig- 
mata, the sterigmata have been digested and the free ends of the 
basidia have been planed down by the zymogenic activity of the 
plasmodium. Apparently, the distribution of the food supply is 
regulated by the large number of nuclei, that seem to be attracted 
* Wilson, The Cell in Development and Heredity, 30. 1900. 
