An Improved Syringe for Injecting Precise Amounts

The method described by Rosenau 1 for injecting precise amounts of fluids into animals is excellent. In the practical application of this method certain difficulties have however been encountered, which, it is believed, can be overcome by improvements in the syringe herein described. The time reqtfired for removing the bulb of and measuring the salt solution into the syringe to wash i t out, after the inoculating fluid has been injected, is considerable and requires the aid of an assistant. Moreover, the cost of the syringe makes it a rather expensive device when a number of these are required, such as are used for determining the strength of toxins and antitoxins. The improvements ha the syringe which I have devised consist of a side arm on the barrel of the syringe and a flexible rubber joint between the barrel and the needle. The value of this side arm is stated below. The flexible rubber joint obviates the necessity of having threads moulded on the lower end of the barrel and allows the t i l t ing of the syringe when in use. The Syringe.--In the text figure, the various parts of the syringe are clearly depicted. The glass portion is made of tubing, the inside diameter of which is from io to i2 millimeters. The total length of the barrel is ioo millimeters. The upper end is flared, to admi t the stopper of the rubber bulb; and lipped. At the other end, a small neck (about 3 ram. in diameter), 15 millimeters long, is made to receive the rubber tubing which holds the needle.