488 



SCIENCE. 



[X. S. Vol. XXI. Xo. .535. 



tions of hog cholera vaccines, usually with 

 the production of large quantities of ag- 

 glutinins, the amount of the vaccine bear- 

 ing no relation to the amount of agglutinin 

 produced. 



(Complete paper will be published in 

 the Journal of Infectious Diseases.) 



A Method for Inoculating Animals ivith 

 Precise Amounts: 'M. J. Rosenau, Hy- 

 gienic Laboratory, U. S. Public Health 

 and ^Marine Hospital Service. 

 The author gives an original method for 

 inoculating animals with precise amounts. 

 With the ordinary methods used in most 

 laboratories there is an unavoidable loss 

 resulting in an error of from one to eight 

 per cent. If the solution is measured into 

 a graduate and then drawn up into a 

 syringe a certain quantity remains in the 

 graduate, and the entire contents can not 

 be expelled from the ordinary piston 

 syringe. In a number of weighings this 

 loss was determined to average aboiit .04 

 c.c. in using 4 c.c. of fluid, that is, about 

 one per cent, of the amount used. 



The new method consists of a battery of 

 syringe barrels, one for each animal. The 

 amount of fluid is measured into the 

 swinge barrel directly, thereby totally 

 eliminating the loss in the graduate. The 

 entire contents of the syringe is expelled 

 by means of a rubber bulb and any fluid 

 remaining behind is washed out with a 

 neutral and sterile solution. The syringe 

 itself is a modification of the Koch syringe. 



In working with different weights of 

 solids, the solution may be made in the bar- 

 rel of the syringe, so that the method is 

 applicable to any sort of work where it is 

 important to inoculate animals with pre- 

 cise amounts. 



The method is especially useful in stand- 

 ardizing diphtheria antitoxin, in detennin- 

 • ing the strength of toxins and in certain 

 lines of physiological chemistry where the 



greatest precision is essential. The battery 

 of syringes is held in a specially designed 

 rack which has many useful points. 



(Complete description in U. S. Public 

 Health and Marine Hospital Service, Hy- 

 gienic Laboratory Bulletin, Xo. 19.) 



A Method for Using Capacity Pipettes: 

 M. J. HosENAU, Hygienic Laboratory, 

 U. S. Public Health and Marine Hospital 

 Service. 



The pipette is held in a retort stand and 

 has a rubber bulb attached to its upper or 

 suction end. By means of a thumb-screw 

 the fluid may be drawn up into the pipette 

 to a point slightly above the mark. The 

 outside of the pipette is then mped with a 

 piece of sterile gauze, and by applying a 

 similar piece of gauze to the tip of the 

 pipette the fluid may be drawn down so 

 that the meniscus rests exactly on the line. 

 The contents of the pipette may then be 

 washed in and out by means of the rubber 

 bulb into the syringe or vessel that is to 

 contain it. 



A Method for Using Delivery Pipettes. 

 M. J. Rosenau, Hygienic Laboratory, 

 U. S. Public Health and ^Marine Hospital 

 Service. 



This is similar to the method described 

 for using capacity pipettes and has a sim- 

 ilar rubber bulb attached to the upper end 

 of the pipette; but in addition, attached 

 to a glass T, is a valve consisting of a piece 

 of rubber tubing controlled by a ]\Iohr's 

 pinchcock. The fluid is drawn up above 

 the mark, and is nursed down by means 

 of a piece of sterile gauze, as related above 

 in using capacity pipettes. By opening 

 the pinchcock the contents of the pipette 

 may be delivered into any vessel desired. 

 The method is both quick and accurate. 



Exhibition of Crdturcs on Starch Jelly and 

 on Silicate Jelly: Erwin F. Smith, U. 

 S. Department of Agriculture. 

 These media were recommended for dif- 



