560 Balls . — Temperature and Growth . 
tatively for its various known components. Every one of the original 
components was present, from Urea to Calcium. 
This analysis does not dispose of an objection that some substance 
might be present in minute traces, too small to be identified by ordinary 
analysis, and that staling was due to its exhaustion. The results of dilution 
experiments with distilled water dispose of this criticism. 
Apparatus. 
Key to Diagrams of Apparatus. 
Copper plate (c.u.) in black. Control-couple in its paraffin bed shaded 
B. 
Control-bath. 
AI. 
Microscope. 
C.c. 
Control-couple. 
M.L. 
,, illumination, 
C. 
Observer’s chair. 
0. 
Air space of chamber. 
G. 
Galvanometer. 
P. 
Stirring pump. 
G.L. 
,, lamp. 
W. 
Waste water. 
G.S. 
,, scale. 
a. 
Asbestos sheet. 
II. 
Heating bath. 
c.m. 
Culture medium. 
K. 
Circuit key. 
CM. 
Copper plate. 
L. 1 . 
Bunsen of H. 
<£• 
Glass carrier-slide. 
1.2. 
Heating lamp of c.u 
w. 
Water. 
The moist chamber. The chamber in which the fungus is grown under 
the microscope is the most important part of the apparatus employed in 
this research. Several different forms were devised for the purpose, but only 
one of these satisfied requirements. 
The essential point is that no change whatever shall take place in the 
concentration of the liquid of the hanging drop. The only way to avoid 
such change is to immerse the chamber entirely in some liquid ; so long as 
the cover-slip is exposed to the air, even when covered by a jacket, these 
changes are likely to take place, on account of the uneven heating of various 
parts of the chamber, and on account of the temperature-lag induced by the 
relatively massive objective. 
The chamber used consists of three parts, as shown in Figs. 1, 2, 3, 4. 
A crystallizing dish containing water stands on a glass plate which is held 
in the jaws of the mechanical stage. Inside this water-bath stands a small 
glass beaker which holds about 30 cc. of culture medium. The moist 
chamber itself stands inside this beaker : it is made from the top of a test- 
tube, over which has been cemented a J in. circular cover-glass, thus forming 
a cylinder which is open at the bottom ; this cylinder is weighed down 
in the beaker by a bent and sealed tube full of mercury, to which tube it is 
fastened by a rubber band ; a bent glass capillary tube passes down between 
the outer wall of the cylinder and the inner wall of the beaker and up inside 
the former to within a millimetre of the cover- slip ; this tube serves to 
remove the air from the chamber and to introduce the gas required for 
respiration. 
