PREPARATION OF SALVARSAN SOLUTION 249 



uses either 0.85 per cent, salt solution or distilled water throughout the 

 preparation with excellent results. The 0.5 per cent, saline solution as 

 recommended by many instead of the 0.85 per cent, is also a super- 

 fluous refinement. It is however absolutely necessary that the sodium 

 chloride is chemically pure and the water used for making up the saline 

 solution be freshly distilled. Then too in the sterilization of the salt solu- 

 tion the latter should not simply be brought to the boiling point, but be 

 kept at this, preferably in the moist heat sterilizer, for a prolonged period 

 of time.) The salvarsan, e.g., 0.6 gm. is added. Upon vigorous shaking 

 the substance goes into solution. It is imperative that the salvarsan be 

 completely dissolved and that no gelatinous drop-like particles remain. 

 Fifteen per cent, caustic soda solution is now added in accordance with 

 the following table : 



0.2 salvarsan (0.456 gm.) requires 0.38 c.cm. 15% Sod. Hydrate =8 drops. 

 0.3 salvarsan (0.654 gm.) requires 0.54 c.cm. 15% Sod. Hydrate = 12 drops. 

 0.4 salvarsan (0.872 gm.) requires 0.76 c.cm. 15% Sod. Hydrate =15-16 drops. 

 0.5 salvarsan (1.09 gm.) requires 0.95 c.cm. 15% Sod. Hydrate =19-20 drops. 

 0.6 salvarsan (1.307 gm.) requires 1.14 c.cm. 15% Sod. Hydrate =23-24 drops. 



(Citron uses a little more of the alkali; for every o.i salvarsan, approxi- 

 mately 0.2 c.cm. sodium hydrate solution is taken.) 



A yellow precipitate at once begins to form and gradually increases 

 until a fine suspension ("neutral suspension") results; finally . when 

 sufficient of the alkali has been added the precipitate redissolves giv- 

 ing a perfectly clear solution. Its reaction is strongly alkaline and 

 would if injected in this concentrated quantity be sufficient to destroy 

 the erythrocytes and injure the vessel wall. Warm salt solution is there- 

 fore added up to 250 or 300 c.cm. If less than 0.6 gm. salvarsan and 

 1.2 c.cm. sodium hydrate have been employed, a proportionately smaller 

 quantity of saline is required. Should this solution not be quite clear 

 or become slightly turbid after a few minutes, a few more drops of 

 caustic soda solution should be added, a drop at a time and waiting two 

 or three minutes after each drop to see if this quantity suffices to clear 

 the solution. Thus prepared, it should be used at once and not 

 allowed to deteriorate by standing, as the oxidation products of sal- 

 varsan are highly toxic. 



(b) The Technique of the Intravenous Infusion. The technique of the 

 intravenous injection of salvarsan and the instruments employed vary 

 with almost every physician who administers it. Each one has his 

 " own method and instrument. " This is hardly necessary. The author's 

 technique is exceedingly simple and fully satisfactory. 



The instrument consists of a long narrow round graduated funnel 

 of about 300 c.cm. capacity; to it is attached a rubber tube interrupted 

 near its lower end by one or two small pieces of glass tubing so as to 



