1 4 GENERAL MOR PHOL OG Y AND BIOL G Y. 



lower plants, has found that many of them belong to a group of 

 colouring matters which occur widely in the vegetable and animal 

 kingdoms, viz. the lipochromes. These lipochromes, which get their 

 name from the colouring matter of animal fat, include the colouring 

 matter in the petals of Ranunculacere, the yellow pigments of serum 

 and of the yolks of eggs, and many bacterial pigments. Among the 

 latter is a lipochrome carotin, which is also the pigment in carrots and 

 tomatoes. The lipochromes are characterised by their solubility in 

 chloroform, alcohol, ether, and petroleum, and by their giving indigo- 

 blue crystals with strong sulphuric acid, and a green colour with iodine 

 dissolved in potassium iodide. Though crystalline compounds of these 

 have been obtained, their chemical constitution is entirely unknown and 

 even their percentage composition is disputed. 



Some observations have been made on the chemical 

 structure of bacterial protoplasm. Nencki precipitated 

 the bodies of putrefactive bacteria with 2-3 per cent 

 hydrochloric acid, filtered them off, extracted with alcohol 

 and ether, and dissolved the residue with .5 per cent 

 potassium hydrate solution. This solution contained 

 an albumin which was fairly constant in its percentage 

 composition in samples obtained from different mixtures 

 of these bacteria, and which Nencki named mycoprotein ; 

 it was soluble in water, acids, and alkalies, insoluble in 

 solutions of neutral salts. The albuminoid constituents of 

 bacteria, however, vary, for from anthrax spores Nencki 

 obtained an albumin which he calls anthraxprotein, and 

 which differs from mycoprotein in its being insoluble in 

 water, acetic acid, and dilute mineral acids. Both differ 

 from nucleo-albumin, a constituent of the nuclei of higher 

 cells, in containing no phosphorus. Other observers have 

 isolated similar bodies having, however, different percentage 

 compositions from those given by Nencki. Buchner 

 isolated a series of bodies from different species of bacteria 

 by dissolving in weak alkali and precipitating the resultant 

 with acid. These he also calls proteins, and adduces some 

 evidence to show that it is to them that the affinity of 

 bacteria for basic aniline dyes is due. They differ from 

 Nencki's proteins in containing phosphorus. According 

 to some recent results the amount of nitrogenous material 

 present varies according to the temperature at which growth 



