Sterile Centrifuge Tubes Research Articles

A NEW METHOD FOR PROCURING BLOOD FOR WASSERMANN TESTS

For the past three years we have drawn bloods for Wassermann tests with a special instrument which we have found convenient and economical. As shown in the accompanying illustration, it is a small metal cap which fits the centrifuge tube into which the blood is drawn. The sides of the cap are flexible so that it will fit tubes of varying sizes within a moderate range. A needle without a hub is sterilized by dry heat in a small test tube with the point of the needle down. When ready for use the needle may be removed without touching the point. It is held by the middle, the wire withdrawn and the butt end of the needle is inserted into a hole in the top of the cap and tightened with a set screw. The cap is placed on the sterile centrifuge tube, and the instrument is ready for use.

An allergic skin reaction to diphtheria bacilli

While immunity in diphtheria may be regarded as being principally antitoxic in nature, it is highly probable that antibodies of a lytic nature may be concerned. With this in view, we have applied an allergic skin reaction in addition to the toxin test of Schick, in studying immunity in diphtheria to the following persons: 1. To 123 persons of various ages, most of whom were healthy and well and had never had diphtheria or received an injection of diphtheria antitoxin. The antigen for the allergic tests was prepared of 45 recently isolated cultures of diphtheria bacilli of various types; each culture was grown in glucose broth for four days and all mixed in a single flask and shaken mechanically with glass beads to break up clumps. To each 100 c.c. of the emulsion was added 5 c.c. of sterile horse serum antitoxin (2,500 units) and the whole shaken at room temperature for four hours. After this time the emulsion was placed in sterile centrifuge tubes and the bacilli separated and washed twice with large volumes of sterile salt solution. After the final washing the bacilli were re-suspended in sufficient sterile salt solution to make, after thorough shaking, about two billion bacilli per cubic centimeter. This emulsion was heated at 60$$ C. for an hour; cultured for sterility and preserved with 0.2 per cent. tricresol. Subcutaneous injection of 1 and 2 cubic centimeters into 250 gram guinea-pigs showed absolutely no evidences of local reaction or general toxemia. In conducting the test, 0.1 c.c. of the emulsion which we have called diphtherin, was injected intracutaneously in the arm. Reactions with the diphtherin were usually well marked and of two types, papular and pustular reactions.