136 BACTERIOLOGY. 



and then a hypodermic syringe may be required. One of the ordinary 

 pattern may be used, but it is very much better to employ a syringe 

 which has been especially constructed to admit of thorough dis- 

 infection. Koch's syringe is a convenient form, the liquid being 

 expressed by pressure on a rubber ball. 



The author has generally preferred to improvise a substitute for 

 the hypodermic syringe which can be quickly made, and is destroyed 

 after use, so that there can be no possible risk of accidentally 

 infecting other animals. A short length of ordinary glass-tubing is 

 sterilised, and plugged at one end with sterilised cotton-wool ; about 

 three inches from the plug a bulb is blown about the size of a 

 marble, and two inches below this the glass is drawn out into a long 

 capillary tube. A sufficient quantity of the liquid to be injected rises 

 up into the tube by capillary attraction, or can be drawn up by 

 means of an india-rubber ball, until the bulb is full. The point of 

 the capillary tube is inserted through the opening in the skin, and 

 gently pushed into the subcutaneous tissue, and then withdrawn for 

 a short distance. By pressure on the bulb the contents of the tube 

 are injected. In dealing with chemical products there is no risk in 

 applying the lips and blowing out the contents of the tube, or indeed 

 of filling it by suction, for if too much force were applied the liquid 

 which might enter the mouth would be stopped by the cotton-wool 

 plug. 



A number of these capillary tubes can be placed in a small case, 

 and when it is necessary to go to a distance to investigate an outbreak, 

 they will be found most convenient to bring back lymph or blood to 

 the laboratory for further study. 



Sternberg takes a piece of glass-tubing, blows a bulb at one end, 

 and draws out the other end into a thin tube. By heating the bulb 

 and then ^dipping the tube into the liquid to be inoculated the latter 

 rises in the tube as the bulb cools. After inserting the point of 

 the tube subcutaneously the bulb is again heated, and the liquid is 

 forced out into the tissues. 



Intravenous Injection. r-A cultivation of micro-organisms may be 

 mixed with sterilised water, and then injected with a syringe directly 

 into the circulation. This may be performed without much difficulty 

 by injecting, with a hypodermic syringe, the large vein at the base 

 of the ear in rabbits, or the jugular vein in large animals. 



Special Operations. In many cases it is absolutely necessary to 

 perform an operation of greater severity. After the administration 

 of an anaesthetic, infective material may be inserted, or injected, into 

 the peritoneal cavity, or injected into the duodenum in the manner 



