THE ALUMNI JOURNAL 14!) 



PROCESS OF MANUFACTURE. 



The chemicals employed to produce the now well-known solution 

 of peroxide are the basic substance, barium dioxide, various acids 

 and water. The acids which have been used are phosphoric, hydro- 

 chloric, sulphuric, oxalic, hydrofluoric. Experience has demonstrated 

 that the most satisfactory acids for the manufacture of the medicinal 

 article are the phosphoric and sulphuric, and the best products to-day 

 are made with these two acids. Barium peroxide is produced by 

 heating barium oxide. Ba O, to a high temperature with access of 

 air. The tremendous heat causes it to take up oxygen forming the 

 dioxide. The barium dioxide of commerce may be classed under 

 two general headings, the German and the English. The English 

 product is considered superior by manufacturers of peroxide on 

 account of its better settling properties, besides it is known to give a 

 better yield. The German barium is much more difficult to work, 

 it forms a light and difficult to settle precipitate and manufacturers 

 generally endeavor to secure the English product for the manufacture 

 of their preparation. The Pharmacopoeia in 1890 gave a process for 

 preparing peroxide of hydrogen, and for a type of pure peroxide the 

 components of this formula can hardly be surpassed. The U. S. P. 

 process with slight modifications was for years and is even now used 

 by one or two manufacturers, but the expense of this process prohibits 

 its use on a large scale, as it costs nearly twice as much as the sulphuric 

 acid process followed to-day. Experience with both processes has 

 taught that undeniably a peroxide made by the action of phosphoric 

 acid on barium dioxide is the purest and best keeping product. Were 

 I a physician I would endeavor to secure the peroxide made with 

 these ingredients for use in my practice. 



For those who would prepare a high grade solution of peroxide 

 in a small way the following outline of the barium and phosphoric 

 acid process may be interesting: 



Fifteen pounds of barium dioxide are placed in a wooden or stone 

 vessel and washed successively five or six times with separate portions 

 of clean water. The barium is allowed to settle after being agitated 

 five or ten minutes with each portion of water and this wash-water 

 is decanted off and thrown away. This removes soluble impurities 

 such as chlorides, etc. The wash-water from the previous batch is 

 placed in another wooden or stone vessel, all of the phosphoric acid 

 is added, several large lumps of ice are introduced and two or three 

 pounds of the washed barium also added ; the mixture is then stirred 



