254 CHEMOTHERAPY 



above, while formerly when the importance of the use of freshly 

 distilled, sterile water, and the necessity of injecting slowly were 

 not sufficiently appreciated, ominous symptoms were fairly common, 

 and caused a great deal of apprehension both on the part of the 

 patient and the doctor. 



That the known contraindications to the use of the salvarsan 

 should, of course, be considered in connection with every case, goes 

 without saying (see below). 



Neosalvarsan. Since salvarsan was first placed upon the market, 

 Ehrlich has attempted to modify the product so that some of the 

 objectionable symptoms which occasionally follow its use would be 

 avoided, and it appears from the most recent reports that he has 

 succeeded in accomplishing this. The result is the so-called Neo- 

 salvarsan, which at the time of writing has not yet been placed upon 

 the market, but is being tested out by various special workers in 

 this field. 



Neosalvarsan is a condensation product of salvarsan and formalde- 

 hyde sulphoxylate of sodium, the reaction taking place according 

 to the equation : 



As = As As = As 



/\ /\ /\ /\ 



NH 2 



NH 2 +HO.CH 2 .O.SONa 



NH.CH 2 .OSONa+H 2 



v > v /n J.x 2 -rxj.v/.v/xa 2 .v/.owi>a, nj.i.2\. / 



OH OH OH OH 



Like salvarsan the new product is a yellow powder, which is 

 readily soluble in water, but unlike the original it forms a neutral 

 solution so that no addition of alkali is necessary before use. As 

 its toxicity at the same time is less, and its spirillocidal action even 

 more intense than that of salvarsan, still better results may be 

 anticipated from its use. 



Schreiber states that the solution should be prepared just before 

 injection, but that it is necessary to use a salt solution of lower 

 concentration, i. e., one not stronger than 0.4 per cent., as otherwise 

 the solution will be turbid, and apparently more toxic. While warm 

 saline (up to 20 C) is to be used in preparing the material for injec- 

 tion, the liquid should not be heated after solution has taken place, 

 for fear of causing the formation of poisonous oxidation products. 

 For the same reason, it is recommended not to shake the solution 

 unnecessarily. Older solutions turn a reddish color, and the same is 



