1 8 APPARATUS 



the serum is accessible to a capillary rubber bulb pipette or to the tip of a haemocy- 

 tometer pipette. In this way dilutions of serum are easily made. 



Quite recently I have been using the blood tube recommended by LYON. To make 

 it heat a 5- or 6-inch section of H inch tubing in the center and draw out as for 

 making 2 bacteriological pipettes. Divide and seal off the large end in the flame. 

 Next seal off the capillary end. Then apply a very small flame to a point on the 

 large end just before it begins to taper to the capillary part. The heat causes 

 the heated sealed off air inside to force out a blow hole. To use: Break off the 

 sealed capillary end and allow the capillary end to suck up blood from a drop just 

 as with the Wright tube. I consider this tube superior to the Wright one. 



Pipettes. The capillary pipette is made by taking a piece of J 



soft German glass tubing, about 6 inches long, and heating in the middle 



in a Bunsen flame, revolving the tubing while heating it. 



When it becomes soft in the center, remove from the flame and with a steady even 

 pull separate the two ends. The capillary portion should be from 1 8 to 20 inches in 

 length. When cool, file and break off this capillary portion in the middle. We then 

 have two capillary pipettes. By using a rubber bulb, such as comes on medicine 

 droppers, we have a means of sucking up and forcing out fluids by pressure with the 

 thumb and forefinger of the right hand. The bulb should be pushed on about H 

 to Y inch; this gives a firmer surface to control the pressure on the bulb. 



A bacteriological pipette is made by drawing out a g-inch piece of tubing about 

 3 inches at either end, then heating in the middle we draw out and have two 

 pipettes similar to the one shown in the drawing. A piece of cotton is loosely pushed 

 in just above the narrow portion. These may be wrapped in paper and sterilized for 

 future use. They may be made perfectly sterile at the time of drawing out. 



Illustrations are given for apparatus for culturing spirochaetes as well as for 

 anaerobic plating methods in Fig. 6. In the same cut is shown an apparatus for 

 filling vaccine ampoules and also our aerobic plating method for class work. 



Where gas is not at hand, the Barthel alcohol lamp gives a flame similar to that 

 of the Bunsen lamp and is equally satisfactory for heating glass tubing. By making 

 a collar with a lateral opening to fit the burner of a Primus lamp a powerful side- 

 flame is obtained which is almost as suitable for glass blowing as the Bunsen blast 

 usually employed. 



The ordinary blast lamp used by plumbers is useful. 



