The Hemolytic Amboceptor 287 



ones that will lead to hemolysis. By increasing the amboceptor 

 we can diminish the complement with the same end-result, a matter 

 that has been graphically shown by Noguchi,* who says "that 

 hemolysis is merely the relative expression of the combined action 

 of amboceptor and complement, and is not the absolute indication 

 of the amount of the hemolytic components present in the fluid. 

 The same amount of hemolysis can be produced by i unit of com- 

 plement and by i unit of amboceptor as by 20 units of amboceptor 

 and o.i unit of complement or any other appropriate combination 

 of these two components." 



As in the performance of the test we work always with i unit of 

 complement, we do not want to unduly disturb its proper propor- 

 tional action by any excessive addition of amboceptor, but simply to 

 increase the latter sufficiently to provide for the accidental presence, 

 in the serum to be tested, of substances affecting hemolysis. Fortu- 

 nately, means are provided for controlling this action, as will be 

 shown below. 



The amboceptor serum keeps indefinitely. When it is to be kept 

 and used from time to time, many experimenters prefer to seal 

 it in a number of small tubes, one of which is opened when the 

 serum is needed, the remainder being kept in an ice-box. Others 

 prefer a stoppered bottle that can be opened and a measured quan- 

 tity removed as needed. The most convenient way of treating it 

 seems to be Noguchi's method of drying it upon filter-paper. 



For this purpose a good quality of filter-paper is cut into strips 

 10 to 20 cm. in length and 6 to 8 cm. in breadth, and saturated with 

 the serum, which is permitted to dry. It is well to make a pre- 

 liminary titration of the serum, for if it be very active it may have 

 to be diluted in order that the piece of dry paper containing the dose 

 be of a size convenient to handle; i drop of serum usually covers 

 about % sc l- cm *> which is about as small a piece as can be measured, 

 cut, and used with satisfaction if sufficient allowances are to be 

 made for variations in distribution and other conditions that may 

 modify the accuracy of the method. If the unit-strength of a serum 

 be, say, 0.00005 an d the dose o.oooi, water should be added to the 

 extent of about 9 volumes and the mixture gently agitated, so that 

 diffusion may occur without frothing. The diluted serum is poured 

 into a large flat dish, and the strips of paper passed lengthwise and 

 slowly to and fro until not only wet, but thoroughly saturated. 

 Each strip, when the dipping is finished, is held first by one end, 

 then by the other, to drain off the free drops, and then laid flat 

 upon a clean glass plate and permitted to dry. The use of an electric 

 fan is recommended to hasten drying. Paper so prepared contains 

 everywhere about the same quantity of serum. 



The real titration of the serum now begins. With a ruler, one piece of paper 

 is divided into squares of, say, ^ cm., and a series of tubes prepared with cor- 



* "Serum Diagnosis and Syphilis," 1910, p. 13 et seq. 



