595 
alcohol will be noticed in the illustration. The door which closes the 
compartment for the test tubes is hinged so as to open downward, 
and is kept from falling entirely open by a thin metal stop on either 
side. The lamp (Fig.62) perhaps deserves a few words of descrip- 
tion. It is a vapor lamp of the kind which may be bought in any 
hardware shop. But it was fitted with a gauze cylinder resting on 
the burner, and a thin sheet-tin chimney, which add greatly to 
the heating power, and the tin cylinder also protects the flame 
from the wind. It also served the further purpose of a support for 
the vessel in which the culture tubes were melted. A deep, nar- 
row tin cup with a wooden handle which just fit over the tin 
chimney when inverted was used to boil the water to melt the agar 
tubes. 
In the kit just described it is possible to accommodate test tubes, 
Petri dishes, and pipettes sufficient for making tests from three or 
four places, provided the test tubes are moderately small in caliber 
and the Petri dishes not too deep. The sizes of those which were 
found convenient are test tubes without lips 15 millimeters in diam- 
eter by 150 millimeters long, and dishes 15 millimeters deep by 100 
millimeters in diameter. 
In addition to the above kit, 5 supply cases (Fig.63), also used for 
shipping', were employed. This case, as the accompanying illustration 
shows, consists of a box with a deep lid hinged on, or more properly of 
2 boxes, one of which is shallower than the other, hinged together and 
closed by a catch. One of these compartments is fitted below for 
holding test tubes ; the upper strip seen in the illustration can be 
removed for convenience in taking out the tubes and replacing them. 
The narrow compartment in the upper part is for pipettes. The 
other section is provided with compartments for Petri dishes, such 
as described in the field kit, and also a compartment for pipettes. 
This compartment was used for a supply of sterilized pipettes and 
the compartment for pipettes in the other section was used for the 
pipettes after they had been used. Both sections measure 14 inches 
from front to back and 10 inches from bottom to top. The shallower 
section is 3 inches deep and the deeper section 4^ inches deep. The 
compartments for the Petri dishes are 4^ inches wide. These are 
inside measurements. The case accommodates Petri dishes and test 
tubes for about 10 tests of the kind already described, each test 
requiring 2 tubes of neutral-red-lactose agar, 2 tubes of litmus- 
lactose agar, 1 sterile empty test tube, 1 pipette and 2 Petri dishes. 
One supply case and the field kit together hold sufficient apparatus 
for about 14 or 15 tests. 
The field kit and one of the supply cases just described were taken 
along each day on the circuit of dairies visited and as soon as the 
