Tetrammine roseo-salts [Co(NH3)4 (H20)21X3.
Pentammine roseo-salts [Co(NH 3) 6 H 2 O] X2.
They are violet-red in colour, and on boiling or long standing with dilute acids they pass into the corresponding roseo-salts.
The pentammine roseo-salts can be obtained from the action of concentrated acids, in the cold, on airoxidized solutions of cobaltous salts.
In many of these salts one finds that the elements of water are frequently found in combination with the metal, and further, that the ammonia molecule may be replaced by such other molecular groups as - N02, &c. Of the types studied the following may be mentioned: the diammine chromium thiocyanates, M[Cr(NH3)2 (SCN)4], the chloraquotetrammine chromic salts, R 1 2 [Cr(NH 3) 4 H 2 0 C1], the aquopentammine or roseo-chromium salts,R 1 3 [Cr(NH 3) 6.
The supposed constancy of forms in Cohn's species and genera received a shock when Lankester in 1873 pointed out that his Bacterium rubescens (since named Beggiatoa roseo-persicina, Zopf) passes through conditions which would have been described by most observers influenced by the current doctrine as so many separate " species " or even " genera," - that in fact forms known as Bacterium, Hicrococcus, Bacillus, Leptothrix, &c., occur as phases in one life-history.
Egg-shaped mass of zoogloea of Beggiatoa roseo-persicina (Bacterium rubescens of Lankester); the gelatinous swollen walls of the large crowded cocci are fused into a common gelatinous envelope.