6 
In endeavoring to overcome these difficulties we have hit npon 
the following simple technique and have nsed it repeatedly in the 
Hygienic Laboratory for several months : 
The Bac is molded in the very beginning over 
the perforated glass frame, from which it is not 
later removed. 
The steps are as follows : 
A glass frame is first made according to the 
method of Novy. Eight to twelve openings, each 
having a diameter of about i inch, are blown as 
closely as possible in the lower part of a small 
test tube, the size and number of the holes de- 
pending on the amount of osmosing surface 
desired. 
The tube is then partially constricted in the 
flame at a point just above the openings. The 
constriction is of such size as to admit a flue 
pipette for inoculation. Some pure gelatin, to 
which is added a little water, is liquefied by heat, 
and with a glass rod a drop of the hot gelatin is 
applied to each individual opening in the glass 
frame, which, when it solidifies, forms a thin 
film which temporarily closes each perforation. 
The tube is now dipped two or three times into 
the collodium solution to a point well above the 
openings but below the constriction. In order 
to remove the gelatin film from the holes, the 
tube is filled with water and it is inverted in a 
larger tube or beaker of water the temperature of 
which is raised until the gelatin melts and runs 
down the inside of the tube through the con- 
stricted part and out into the water (see cut). 
We then have the collodium firmly adherent 
to the glass frame, covering its openings, well 
supported and ready to stand, without tearing or 
leaking, the manipulations of sterilization, filling. 
The glass frame inclosed m _ ^ \ ^ ^ 
atesttubeof hot water to re- inoculation, Sealing', implantation and removal 
move the gelatin from the . T 
perforations. from the abdominal cavity. 
The ease with which this technique can be carried out will, we 
think, appeal to those who have had experience with other methods.* 
^ The glass frame may be further improved by directing the gas blast flame 
against the tube on opposite sides just below the constriction until the glass 
becomes softened and indented. These two flattened surfaces afford a good 
place for grasping the frame with a pair of forceps during the sealing off and 
implantation. This overcomes the slipping and turning which occur on attempt- 
ing to hold firmly a perfectly round tube. 
