Te Le gee ee ee 
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1892. Effect of Movement upon Growth of Lower Organisms. 9 
inoculated ‘‘seed” by shaking ,a number of samples were 
taken and from these the number of cells in a certain volume 
was determined by means of Nachet’s hemacytometer. By 
means of this apparatus equal known quantities were used 
each time. A number of counts, usually not less than one 
- hundred, were made, so as to make the average as accurate as 
possible. At first each flask was inoculated and counted 
separately, but it was soon found that more accurate results 
could be secured by determining the number present per 
unit of volume for the whole amount of the fluid and then 
dividing it into two equal amounts. he danger of contamin- 
ation from outside influences is of less consequence than the 
* difference in units of volume which inevitably occurs where 
the determinations are made separately of the amount of 
‘*seed” added to each flask. After counting, the two flasks 
were subjected to exactly the same conditions, with the ex- 
ception that one of them was kept in a state of constant 
agitation. j 
This was secured by the rotation of a vertical shaft to which 
was attached a horizontal bar. This bar inits rotation struck 
and lifted the flask, which on its return swing struck against 
an upright standard. The stroke by the rotating bar and the 
sudden checking of the movement of the flask kept the fluid 
in a state of Nae ae agitation. All points of contact of 
the flask with the bar and es were sheathed with 
rubber to prevent Bue The power was furnished by a 
small reaction water wheel and was eamiticd by a belt from 
a pulley on the motor to a cone pulley fastened to the upright 
revolving shaft. This cone pulley enabled me to vary the 
rapidity of the revolution of the horizontal arm at pleasure. 
After allowing a certain time for growth, samples were 
withdrawn and counted in the same way as before. The 
number per unit of volume at the close of the experiment 
divided by the number per unit of volume inoculated as 
‘‘seed” gives the ratio of increase for each flask. As a 
substance carefully collected, dried, weighed, and the ratio 
thus determined. For this, the ash constituent of the cells 
can be neglected without interfering materially with the 
accuracy of the resu 
In the majority of the experiments, Monzlia candida, a 
yeast-like germ capable of inducing alcoholic fermentation in 
most sugar solutions, was used for the tests. Two other 
