822 



SCIENCE 



[N. S. Vol. XXXII. No. 832 



stable form in contradistinction to the 

 stable pentavalent form, in which arsenic 

 occurs in atoxyl, arsaeetin and the cacody- 

 lates. Owing to the presence of the two 

 hydroxyl groups the product possesses acid 

 character, enabling it to form weak salts 

 with bases, and owing to the presence of 

 the two amido groups it also has basic 

 character, enabling it to form salts with 

 acids. But either form of salt is of neces- 

 sity unstable, which makes the administra- 

 tion of the new product a difficult one. 

 The hydrochloride when dissolved in water 

 is decomposed and liberates hydrochloric 

 acid, which causes great pain when in- 

 jected into the body. The practise at the 

 present time is therefore to add enough 

 alkali to the solution to neutralize the free 

 acid, by which treatment the free base is 

 precipitated and is then injected in the 

 form of a suspension. 



From oxyarylarsinic acids we obtain by 

 condensation with chloracetic acid arylgly- 

 col arsinie acids, which upon reduction 

 furnish arsenoarylglycolic acid 

 O— CHjCOOH 

 /\ 



Phenylglycolarsinic acid 



COOH— CHo-O- 



-CHj— COOH 



\— As=A8— ;/ p- 

 Arsenophenylglycolic acid 



Among other substitution products we must 

 mention an iodin derivative, the p.iodin- 

 phenylarsinic acid and its diiodide: 

 I I 



/\ 



I I 

 I I 



\y 



I /OH 

 As==0 

 \0H 



A 



i I 

 \/ 



A8< 



\l 



and a camphor combination, the dicam- 

 phorarylarsinic acid, obtained by the ac- 

 tion of arsenictrichloride upon sodium 

 camphor : 



/CH— AsO-CH^ 

 "H CO^ 



*\r 



An interesting combination of the mer- 

 cury treatment hitherto in use with the 

 new method by means of the arsenic prep- 

 arations is represented by the synthesis of 

 the atoxylate of mercury 

 NH, 



I I 



./ 



AsO<:^ Hg 



\ 



with which Uhlenhuth, the originator of 

 the substance, has obtained excellent re- 

 sults. 



If, after all that has been stated above, 

 we now define chemotherapy, it can per- 

 haps best be described as the science deal- 

 ing with the treatment of internal para- 

 sitic diseases by means of preparations 

 synthetized with the object of combining 

 the maximum power of efficiency in the 

 destruction of the greatest variety of pro- 

 tozoa with the minimum poisonous action 

 upon the patient's tissues, this combination 

 of properties being primarily established 

 by animal experimentation. 



In contradistinction to chemotherapy, 

 serumtherapy is the method of treating 

 bacterial infections by means of antibodies 

 generated by the diseased organism itself. 



If, as seems improbable from the bril- 

 liant results reported in such abundance 

 by many of the greatest authorities in the 

 medical world, the new remedy should 

 suffer a setback through later observations 

 of serious after-effects, it would not de- 

 tract in the least from the magnificent 



