223 

 pirrrrrKS for iKti.nixr; and measuking fluids. 



("II AKI.KS A. I'.KIIKKNS. 



(I'lirdiic riiivcrsily. 7,:i f.-iNcI tc. Iiid.l 

 'I'liorc arc many apiilicaUfHis in liaclcrioloyy ami especial 

 for iiipctles wliicli will servo the double purpose df luildiim 

 fluids. We lia\(' de\ ised such i»iocos of apparaliis wliicli arc 

 sinictioii. easy and coiiveiiieiit fo operate and \\lii<li have 

 satisfactory in our laboratory. 



Fitcure I represents the pipette for use w lien it is desired Id 

 li(|ui(ls. Tlio Klass parts and rubber coniieclidns are sterilize 

 way and assoniblod asoptically. 



I'.y ivloasinj; the clamp (C) on rubberiii.i;-tubiiii,' connection (I>) tho 

 sterile fluid contained in the reservoir ( I*. ) wliicli may be of any suitable 

 shape, will flow into the i>ipette (G) which is of the desired calibration. 



The side-arm (E) wiiich is plugfjcd with sterile cotton (F) to avoid air 

 contamination, compensates for the air disphiced by the liquid eiiteriii}: 

 the calibrated tube (d) or replaced when the clamp (J) on rubbor-tubini,' 

 connection (I) is released thus permitting the measured fluid to flow- 

 thru the capillary-tubiuff (K). The latter may be protected by a sterile 

 test-tube (M) plugged with cotton (L). 



Applying negative or positive pressiu'e by means of the rul)ber-tubing 

 III) which is connected to the side-arm. the liqiiid which i-emains in the 

 capillary-tubing or pipette proper or in both may bo removed. The small 

 amount of sterile liquid which may be discharged from time to time from 

 the same may be collected in sterile tubes or flasks and thus prevent waste 

 of fluid. However, it is not advisable to return such material to the stock 

 solution in the reservoir for fear of contamination. 



After the opening in the capillary-tubing has been sealed in the flame 

 the liquid is stored by placing the appartus in the refrigerating-room. When 

 more fluid is to be used a file-scratch is made near the sealed end of the 

 capillary-tubing. It is broken off. the opening sterilized by flaming and the 

 pipette is manipulated as before. It may be advisable to warm the liquid 

 before so doing. Of course, sterile fluid may be taken directly from the res- 

 ervoir. 



Evaporation of the material may b(> cut down to a negligible quantity l)y 

 covering the cotton stopper (A) in tho holding-chamber with a rubber cap 

 or by inverting a test-tube over it etc.. and by tying a knot in the rubber- 

 tubing (H). 



In this way a sterile liquid may be conveniently stored with a minimum 

 amount of evai)orati(m and used in definite quantities without becoming 

 contaminated. 



In serological work where sterility is not necessary but where it is 

 essential to bring the reacting substance to an equal volume by adding 

 physiological salt solution the pipette as .shown in figure II may be used 

 fo an advantage because of its convenience in operation and time saving. 



The apparatus is entirely glass in construction and in ojieration is similar 

 to the ]>i])ette iireviously considered. A rack holding the fub(>s cont:iining 

 the reactin.g substances is ])laced under tho piiK'tte and the re(piired aniount 

 of physiological salt solution is added to each tube. 



