﻿332 The Philippine Journal of Science \m 



against the walls of the tube. It should be filled 4 or 5 mil- 

 limeters back of the bend. It is then adjusted as usual and the 

 organism taken from the droplet in which it is isolated. The 

 organism must actually enter the tube and not adhere to the 

 margin of the opening. The tip is now brought into a hang- 

 ing drop of sterile broth or salt solution for a few seconds, so 

 as to wash the organism well back from the tip. The pipette 

 is removed from the holder, and is ready for inoculation. The 

 index finger and thumb hold the capillary; the middle finger 

 is extended and the end of it pressed against the bend of the 

 pipette, in order to push the point through a fold in the skin. 

 By blowing into the rubber tube, the liquid in the tube is in- 

 jected, the liquid back of the bend serving to wash out the or- 

 ganism. The point usually enters easily into the skin of ordinary 

 laboratory animals, and leaves a wound scarcely discernible with 

 a lens. If the opening in the pipette is too fine, there is some- 

 times difficulty in forcing out the dose. In this case, one may 

 enlarge the opening by breaking off a small portion against 

 any sterile surface. It is obvious that a tip broken off obliquely 

 will penetrate the skin much more easily than a blunt one. If 

 desired, one may wash back the organism with sterile fluid in 

 the test tube just before breaking off the tip; but, in any case, 

 it is best to wash it a short distance back before removing it from 

 the isolating chamber. Large animals with very thick skin may 

 be inoculated in the mucous membrane of the mouth. I have in- 

 oculated carabaos in this way. Any desired number of organisms 

 may be counted out and inoculated in one dose ; or one organism 

 may be isolated, allowed to grow in the hanging drop, and its 

 offspring inoculated, leaving one or more to grow in the hanging 

 drop as a control. 



Special experiments,' in which the organism has been dis- 

 charged into a nutrient medium instead of into an animal, have 

 shown that the organism comes out of the pipette and does not 

 adhere to the glass. Further, I have obtained a fatal infection 

 in mice following the inoculation of a single anthrax bacillus " 

 and a considerable proportion of positive results with single 

 plague organisms inoculated into monkeys and guinea pigs.^^ 



A modification of the inoculation pipette is of advantage in 

 some cases, for example, in the piercing of a very tough skin or 

 in intravenous or intraperitoneal inoculation. Here the tip of a 



'Journ. Infect. Dis. (1909), 6, 634. 

 » Ibid. 

 "This Journal, Sec. B (1912), 7, 251. 



