Oe a 
1892.] Liffect of Movement upon Growth of Lower Organisms. 13 
It will be noted that while no uniformity seems to exist in 
the ratio, the amount of fermentation products of the cells in B 
is a/ways greater than in A, while the amount of organic matter 
formed stands in an inverse relation. 
We may now ask what is the cause of this increased rapidity 
of growth when agitated. The experiments detailed above 
allowed considerable aeration .during the movement and as 
this factor seemed most prominent, the experiments were re- 
peated in such a way as to increase the aeration and diminish 
as much as possible the movement of the fluid. If aeration 
increases the growth of the organisms, there should be an in- 
crease in the ratio between A and B. 
Exp. I. An Esmarch’s coiled glass tube, such as is used in 
bacteriology for air determination in fluid cultures, was inocu- 
‘lated with Monilia candida and air drawn slowly through the 
coil by the aid of an aspirator. The small bubbles of filtered 
air slowly travel the spiral, so that a considerable quantity of 
oxygen ought to be absorbed by the liquid. In this way 
aeration is considerably increased while the movement of me 
fluid is much reduced. At the end of 42 hours growth, i 
was found that the germs which were oe had ces 
2.5 times as fast as the non-aerated cultur 
Exp. II. A 500 c.c flask was partially filled with a nutrient 
solution and inoculated with freshly grown Monilia candida. 
The mouth of the flask was closed by a triple-perforated 
sterilized rubber cork. In two of the openings, glass tubes 
were inserted and the lower ends were drawn out into fine 
points. The third opening was closed by a bent open tube, 
the outer end of which was directed downwards. These 
glass tubes were closed with cotton-plugs and sterilized before 
being put in place. The two capillary tubes were connected 
to the blast of a filter pump and thus a stream of filtered air 
was forced into the fluid culture. The fine bubbles of air 
rising to the top of the fluid escaped through the bent exit 
tube. In 30 hours there was found to be 2.2 times as many 
cells per unit of volume in aerated flask as there were in 
non-aerated. 
Exp. III. In both of the preceding experiments aeration 
was increased as much as possible while the movement was - 
lessened. In\this experiment the reverse order was followed. 
A thick glass tube was sealed at one end and at 5 cm. dis- 
tance from this end, a large bulb capable of holding 300 cc. 
