Reprinted from the New York Medical Journal, 
for May 16. 1896. 
A MACHINE FOR TUBING BACTERIAL MEDIA. 
By Harrison G. Dyar, A. M., Ph. D., 
ASSISTANT IN BACTERIOLOGY, DEPARTMENT OF PATHOLOGY, COLLEGE OF 
PHYSICIANS AND SURGEONS, NEW YORK. 
In preparing large quantities of standard media for the use 
of classes in bacteriology, it has been found that considerable 
time was wasted by the older methods of tubing the material. 
In order to shorten this irksome portion of the process, the ap- 
paratus here described was devised by the instructor and his as- 
sistants. While not embodying a new principle, the machine 
has proved of great convenience, so that it has been thought 
worth while to describe it for the benefit of others in a simi- 
lar position to our own. 
The machine is capable of being operated by one man, for 
all media in ordinary use which may be rendered sufficiently 
fluid, at the rate of five hundred to six hundred tubes an hour. 
This includes the measurement of the amount in each tube 
with considerable accuracy, while the position and motions 
required for the operator are comfortable and not fatiguing. 
The apparatus (see figure) rests on an ordinary table (A). 
A frame of board (B) supports it, and also serves as a recep- 
tacle for empty test tubes (C), which feed down to the hand 
as shown. A funnel (D), surrounded by a water jacket (E), 
capable of being kept hot by a lamp (F), contains the medium 
to be tubed. This feeds down a rubber tube (G), closed by 
an ordinary spring clamp (II). This clamp is opened by a 
pedal used by the left foot (I) and attached to a bar (K) by a 
string passed over three pulleys. The tube feeds into a larger 
graduated glass tube (L). which is emptied by a short rubber 
tube (M), closed by a clamp similarly operated by the right 
foot on a second pedal (N). The pedals are balanced on a 
central bar, so that when the tubes are both closed the feet 
are at rest, while a depression of the toe of either foot opens 
Copybight, 1896, by D. Appleton and Company. 2 
A MACHINE FOR TUBING BACTERIAL MEDIA. 
the corresponding clamp. Both hands are left free for ma- 
nipulating the tubes and placing them in the basket (0), 
while the receptacle (L) is refilling for the next tube. The 
amount in each tube is measured by the graduation of this 
receptacle. An inverted flask with thistle tube may be sub- 
stituted for the funnel containing the medium.