8 THE ALUMNI JOURNAL 



L. Gallois has found that repeated apphcatons of peroxide to a hairy 

 surface on the skin act as a depilatory, the hair first becoming brittle 

 and breaking off. 



C. T. Tyrer considers hydrochloric acid the worst protective agent 

 and phosphoric acid the best, glycerin coming second. Champagne, 

 soda water and beer bottles with patent stoppers he finds the best for 

 holding peroxide. 



In treating a case of Rhus or ivy poisoning, peroxide was used. A 

 white cloth bandage was wrapped about the wrist and kept wet with 

 peroxide. The treatment was discontinued in the afternoon and the 

 bandage removed before retiring. On the second day treatment of 

 the patient was continued by moistening the bandage with several 

 applications of peroxide in the morning. Several hours later an odor 

 of burning cloths and a severe pain in the wrist directed the patient's 

 attention to the bandage which was smoldering and already charred 

 black in many places. Before it could be removed it had caused 

 several burns on the wrist which required weeks to heal and left scars 

 for several years. The probable cause of this phenomenon was the 

 presence of a slight amount of free sulphuric acid in the peroxide. 



CHEMISTRY OF PEROXIDE. 



Peroxide of Hydrogen is produced by the action of dilute acid upon 

 Barium Dioxide by which an exchange of atoms is effected. When 

 manufactured with phosphoric acid the reaction takes places as fol- 

 lows : 



Ba Oo+H3PO,=Ba HPO,+HoOo. 



When sulphuric acid is used in conjunction with phosphoric a 

 further reaction occurs : 



Ba O^+Ba H PO,-H2 HoSO,=H20,+2 Ba SO.+HgPO^. 



Hydrochloric acid reacts as follows : 



Ba 92+2 H Cl=:Ba Clo+HoO^. 



Hydrofluoric acid reacts on barium dioxide in the following manner : 



Ba O2+2 HF:=Ba F.+H^O,. 



The titrimetric estimation of peroxide with N/io potassium per- 

 manganate takes place according to the following reaction: 



5 U.O^+2 K MnO,+3 H3SO,=50o+2 Mn sb,4-ICS04-t-8 H.O. 



Estimated with N/io sodium thiosulphate the equation is as fol- 

 lows : 



H20,+2 K I+H.SO,:=L+K,SO,+2 H^O; 



I0+2 Na, 5203^=2 Na I+Na, S^Og. 



