282 Wassermann Reaction for Diagnosis of Syphilis 



cerebrospinal fluid, the milk, the urine, and the other body fluids 

 through the blood, in which it exists in greatest concentration. The 

 blood is, moreover, readily obtainable for study, which is another 

 reason it is at present used for making the test under all ordinary 

 circumstances. Noguchi, who works with very small quantities of 

 the reagents, secures the blood by obstructing the venous circulation 

 of the thumb or of a finger by means of a rubber band (see directions 

 for obtaining the blood for making the opsonic index) but the greater 

 number prefer to obtain it by introducing a large hypodermic needle 

 into one of the veins near the bend of the elbow. The arm above 

 the elbow is compressed by a fillet, as though for the purpose of 

 performing phlebotomy, and a conspicuous vein selected for the 

 purpose. The skin is first carefully washed, then treated with 

 tincture of iodin. If the patient is nervous, a momentary spraying 

 with chlorid of ethyl will make the operation entirely painless. 

 Some prefer to use the iodin without the preliminary washing, be- 

 lieving that soap makes it difficult for the iodin to effect satisfactory 

 disinfection of the skin. The sterilized needle is thrust into the 

 vein, care being taken that the vein is not too compressed and the 

 point of the needle thrust entirely through instead of into it. From 

 15 to 25 cc. of blood may be withdrawn in a Keidel tube, or into a large 

 syringe or may be allowed to flow into a sterile test-tube. The blood, 

 however secured, is permitted to coagulate and the clear serum re- 

 moved by a pipette, or the clotted blood is placed in a centrifuge 

 tube and whirled, so that clear serum is secured in a few minutes. 



As normal human blood-serum, when fresh, contains a certain 

 amount of complement which would interfere with the success of 

 the experiment, the serum is next placed in a test-tube and kept 

 in a water-bath between 55 to 58C. for a half -hour. This degree 

 of heat destroys the complement and leaves the complement-fixing 

 substance uninjured. The serum is now ready for use. 



(3) The Complement. The complement generally employed is 

 contained in the blood of a healthy adult guinea-pig. To obtain 

 it a piece of cotton moistened with ether or chloroform is held to 

 the guinea-pig's nose until it becomes unconscious, when the head 

 is forcibly extended and a longitudinal incision made through the 

 skin of the neck. The skin is then drawn back between the finger, 

 on the one side, and the thumb, on the other side, of the operator's 

 left hand, while, with a sharp knife held in the right hand, he cuts 

 through all the tissues of the neck down to the spinal column and 

 thus opens both carotid arteries. The spurting blood is caught in 

 a sterile Petri dish and the animal permitted to bleed to death. 

 The blood soon coagulates when undisturbed, and in a short time 

 clear serum exudes from the clot. As, however, the complement 

 seems to be at least in part derived from the corpuscles, the serum 

 should not be removed as soon as it forms, but permitted to remain 

 in contact with the clot for three hours. If it is desired to save 



