340 CHEMICAL DISCOVERY AND INVENTION 



conjunction with A. Bertheim, proved that atoxyl is the sodium 

 salt of para amino phenyl-arsinic acid, the formula of which is 



/ONa 

 AsO^-OH 



X C 6 H 4 .NH 2 



The use of atoxyl has been practically abandoned in favour of 

 the more complicated dioxydiaminoarsenobenzene, 



As-C 6 H 3 (NH 2 )OH 



II 

 As-C 6 H 3 (NH 2 )OH 



the hydrochloride of which is salvarsan. The rapid rise into 

 notoriety of this remarkable substance is known to all the world, 

 but it appears to be still doubtful whether it is effectual in all 

 cases, and its action occasionally becomes poisonous. This is 

 probably partly due to the fact that on exposure to the air it 

 readily undergoes oxidation yielding a more poisonous com- 

 pound. 



A large number of researches have been carried out on aromatic 

 compounds containing the elements phosphorus, arsenic, and 

 antimony, which in the periodic scheme are members of the same 

 family as nitrogen. Some of these may hereafter be found to 

 possess medicinal properties similar to those of salvarsan and, 

 it is to be hoped, less dangerous. Announcements from time to 

 time appear in the newspapers, of which the following is an 

 example, 22nd March, 1916 : 



" At the last meeting of the Academy of Sciences, a Paris 

 telegram states, Professor A. Laveran described a new specific 

 for syphilis, the discovery of Dr. Danysz, of the Pasteur Institute, 

 who claims that it is by far the most effective yet found. The 

 remedy is a preparation based upon a mixture of arsenic, anti- 

 mony, and silver, which the discoverer has named c 102 ' or 

 ' Margol.' " 



Time alone can show whether these expectations are justified. 



On a previous page several of the natural drugs provided by 

 the vegetable kingdom were mentioned. Of these the most 

 important by far are those which are familiarly known as 

 " alkaloids " inasmuch as the majority of them possess very 

 powerful physiological action, and in many cases act as violent 



