XA JURE NOTES 
observers were able to study and determine even the simplest 
facts in tlie life-history of minute living things which are found 
everywhere, from the profoundest depths of the ocean to the 
untrodden pinnacles of the highest mountains. 
The first observers, Ehrenberg in Germany and Pritchard 
and others in England, hardly suspected that the slimy sub- 
stance filling the cells of plants like the honey in the honey- 
comb was in reality the basis of the plant’s life, and that at 
times, under certain determined circumstances, this substance 
was launched freely into the watery medium in which the parent 
lived, and became endowed with free motion. At other times 
this substance, which has been named “ protoplasm,” assumes 
a globular or ovoid shape, and by means of a “ cilium ” or eye- 
lash-like appendage, or, m some cases, many cilia, is propelled 
with greater or less activity through the water into which it has 
been launched. Eventually motion is arrested and the plant- 
germ settles down to develop into a perfect specimen of its kind. 
Among the most striking phenomena observed in connection 
with these living protoplasts is without question this temporary 
locomotion of such protoplasts as have quitted the cell-cavities 
in which they were formed and are wandering about in liquid 
media, their number as well as the variety of their forms being 
extremely great. The average rate of motion has been estimated 
at from 7 to 8 mm. a minute. 
Creeping masses of protoplasmic jelly sometimes move in the 
direction of incident light, at others they avoid light and hide in 
obscure places, wriggling through the interstices of heaps of bark 
or into the hollows of rotted tree-trunks, or they may creep up 
the stems of living plants, or glide in a viscid condition over the 
browm earth or rocks. 
Vaucheria clavata is a very common form of fresh-w’ater algae, 
which makes its appearance first in green water, in puddles 
and water-filled ruts in our country lanes, and has a most in- 
teresting life-history which may be observed and studied by the 
possessor of any ordinary compound microscope. Let the would- 
be observer place a drop of this green water on an ordinary 
glass slide and cover it with a thin glass cover, or, what is better, 
use the little instrument called an animalcule cage, for the pur- 
pose, and place it on the stage of the microscope under a quarter- 
inch power. A wondrous revelation will then meet the eye : 
what seem like points of green light are seen moving about with 
great velocity through the liquid, revolving and threading their 
way with a constant, even progress, and, if the power of the 
lens be increased and the light regulated by the diaphragm, 
each globule of living green jelly will be found to be furnished 
with moving cilia which are protruded all round through the 
walls of the enveloping pellicle. These, by their active vibra- 
tion, cause it to move freely in any direction with considerable 
rapidity. 
Other forms of protruded protoplasm have only a kind of 
