116 LABORATORY EXERCISES IN BACTERIOLOGY. 



capillary diameter and extent of several feet. As soon as cool the tube is cut or broken 

 so that as much as possible of a uniform caliber of the capillary portion remains attached 

 to one end of the original glass tube.) Into this capillary is drawn a known quantity 

 of water (as 0.5 cubic centimeter) from a watch-crystal into w r hich it has been carefully 

 measured. The length of the column of water in the capillary is marked with a pen, 

 and convenient divisions for fractions of the contents are similarly marked at proper 

 intervals upon the glass. The water is now blown out, the tube washed with alcohol 

 and ether to insure dryness, and then sterilized in any large oven in the usual manner, 

 a plug of cotton having been previously placed in the larger end. (In the absence of 

 oven large enough to accommodate a long pipette, it may be sterilized by drawing it 

 full of a disinfectant solution and immersing its capillary end in the disinfectant, and 

 thereafter washing out the disinfectant with well-boiled water, and rinsing with alcohol 

 and ether.) Thus prepared it is to be used in the same manner as an ordinary pipette 

 in inoculation exercises. 



Syringes. For collection of liquid material and its convection to the nutrient 

 material from a living diseased individual, as splenic blood, blood from a vein, the 

 contents of a cyst or of an abscess or blister, syringes are often used. These should 

 be of a form and construction easy of sterilization, as Koch's inoculation syringe (Fig. 

 37). All parts of the syringe having been sterilized (glass and metal portions in auto- 

 clave or oven, rubber parts in disinfectant solution and boiled water) and adjusted, 



U4 



FIG. 37. KOCH'S INOCULATION SYRINGE. 



the needle is thrust into the tissues to the source of the desired material and the liquid 

 drawn into the syringe. (Any part of an exposed surface to be punctured should 

 have been previously sterilized in surgical fashion.) Observing the usual precautions, 

 the needle, after withdrawal from the tissue, is introduced into the culture tube, a 

 drop or more of the contents expressed upon the nutrient medium, the syringe disposed 

 of, the tube closed with the usual precautions, and the added matter diffused in the 

 medium by gentle agitation. The syringe is then to be cleaned and sterilized and its 

 contents destroyed. 



A very convenient substitute for a syringe is the Sternberg bulb (Fig. 38), which 

 may be made in a few minutes from a piece of soft glass tubing. (One end of a piece 

 of glass tube about eight or ten inches in length is fused shut in the Bunsen flame and 

 about an inch of the closed end softened, from which a bulb is blown by the operator to 

 half an inch or an inch in diameter. After having become cool, the tube, as close to the 

 bulb as possible, is softened in a narrow flame for a distance of half an inch or an inch 

 and drawn to a fine capillary end, which if desired may be sealed shut in the flame.) If 

 sealed in its manufacture, the air in the bulb will be much rarefied and the interior 

 of the appliance may be regarded as having been sterilized by the heat applied during 

 manufacture. As a uniform precaution, however, it is well to sterilize the bulbs, 

 whether sealed or not, in a metal box or wrapped in paper, in the oven, and the pro- 

 tection of the box or cover retained until the bulb is to be used. In use, the air in the 



