262 BIOLOGY AND ITS MAKERS 
(with slight verbal alterations) says: “The spectacle afforded 
by the wonderful energies imprisoned within the compass of 
the microscopic cell of a plant, which we commonly regard 
as a merely passive organism, is not easily forgotten by one 
who has watched its movement hour by hour without pause 
or sign of weakening. The possible complexity of many 
other organisms seemingly as simple as the protoplasm of 
the plant just mentioned dawns upon one, and the compari- 
son of such activity to that of higher animals loses much 
of its startling character. Currents similar to these have 
been observed in a great multitude of very different plants, 
and it is quite uniformly believed that they occur in more 
or less perfection in all young vegetable cells. If such be 
the case, the wonderful noonday silence of a tropical forest 
is due, after all, only to the dullness of our hearing, and could 
our ears catch the murmur of these tiny maelstroms as they 
whirl in the innumerable myriads of living cells that con- 
stitute each tree, we should be stunned as with the roar of a 
great city.” 
THE ESSENTIAL STEPS IN RECOGNIZING THE LIKENESS OF 
PROTOPLASM IN PLANTS AND ANIMALS 
Dujardin.—This substance, of so much interest and im- 
portance to biologists, was first clearly described and dis- 
tinguished from other viscid substance, as albumen, by Félix 
Dujardin in 1835. Both the substance and the movements 
therein had been seen and recorded by others: by Résel 
von Rosenhof in 1755 in the proteus animalcule; again in 
1772 by Corti in chara; by Mayen in 1827 in Vallisnieria; 
and in 1831 by Robert Brown in Tradescantia. One of these 
records was for the animal kingdom, and three were for 
plants. The observations of Dujardin, however, were on a 
different plane from those of the earlier naturalists, and he 
