THE NEW YORK JOURNAL OF PHARMACY 



acetate a heavy ppt. is formed. The 

 ppt. thus obtained is collected on a 

 plain, folded filter allowed to drain, 

 washed several times with cold dis- 

 tilled water and dried. 



The dried ppt. is placed in a porce- 

 lain capsule, covered with a saturated 

 solution of bichromate of potash in 

 strong sulphuric acid and (5cc being 

 sufficient) allowed to stand for 15 

 minutes. Distilled water is tlien 

 added and the solution transferred to 

 a sediment glass. After complete sed- 

 imentation several slides are prepared 

 from the sediment and examined mi- 

 croscopically. If agar agar is present 

 the two diflferent types of diatoms 

 represented in the accompanying draw- 

 ing will be found. 



THE CLASSIFICATION AND 

 IDENTIFICATION OF MAN- 

 GANESE. 

 Anton Vorisek. Phar.D.* 



Manganese. Mn, occurs free only in 

 meteorites. Its abundant compounds 

 are found widely distributed, and in 

 minerals they are found chiefly together 

 with iron. ^Manganese is present in sea 

 water and in some spring waters. The 

 ashes of many plants contain manganese 

 and there are minute amounts of it 



found in the animal tissues. In its ele- 

 inentary (metallic) form Mn is import- 

 ant only in the making of steel and as 

 a component of an alloy, the so-called 

 manganese bronze. 



The compounds of Mn possess con- 

 siderable commercial importance ; some 

 of them, particularly the organic ones, 

 are used medicinally. Lately a relation 

 of Mn comi)oun(ls. present in the soil 

 to the grow til of plants, has been studied 

 and Mn oomi)oiuKls considered as prom- 

 ising fertilizers. 



The common .salts of Mn are the 

 "manganous,"' in which the metal is 

 present as the divalent basic component 

 (Mn++). In most of its oxides Mn 

 lias a higher valence and exists also 

 in two acidic components, the man- 

 ganate ( MnO^—) , and permanganate 



Classification. 



The basic component (Mn++) was 

 originally classed (Fresenius) as a mem- 

 ber of the 3rd group, /. e., together 

 with Zn, Ni, Co, Fe, Al and Cr, a 

 grouping which is still followed by 

 many. In separations it is precipitated 

 as a hydrated MnS by ammonium sul- 

 fide, the group reagent for that group. 

 Later it was found that the members of 

 this large group can be, with advantage, 

 divided into two separate groups, name- 

 ly, the 3rd and 4th, for which ammonium 

 hydroxide and ammonium sulfide serve 

 as the respective group reagents. In 

 analysis the separation of these two 

 groups depends on the property of the 

 divalent components (4th group) to 

 form soluble complex ions with NH^, 

 which the trivalent ones (3rd group) do 



*Professor Vorisek is a graduate of N. Y. 

 C. P., '98. 



