LIPOCHROMES. 139 



slender motile bacillus, which does not liquefy gelatin. As is 

 indicated by its second name, the seat of the dirty red colouring 

 matter is not in the vegetative form of growth, but in the endo- 

 spores. The so-called (motile) " Kiel bacillus" found by Breuning 

 in the Bay of Kiel, occurs generally as long rods (0.8 //. broad, by 

 2.5-5 /u, long), which liquefy gelatin. There is great similarity in 

 the red colouring matter produced by this bacillus and Micrococcus 

 prodigiosus, but the former microbe is distinguished by its greater 

 susceptibility to direct sunlight, which, according to the researches 

 of E. LAURENT (I.), permanently destroys its chromogenic power. 

 A similar effect is produced by the presence of carbohydrates in 

 the medium, the Kiel bacillus, in such event, elaborating no 

 colouring matter. The following chromoparous red species will 

 only be briefly alluded to : Bacillus ruber, discovered by Frank 

 and described by COHN (II.) ; Bacillus indicus, discovered in the 

 contents of the stomach of an East Indian ape ; the Bacillus 

 granulatus of Babes ; Bacillus corallinus, isolated by C. SLATER (I.) 

 from atmospheric dust, and the Bacillus rubellus, discovered by 

 OKADA (I.), which forms endospores and thereby assumes the 

 clostridium form. 



Greater interest attaches to several red and yellow species 

 studied by ZOPF (IV.), and especially as regards their colouring 

 matters, which were named by him lipochromes or fat-colouring 

 matters. These are excreted from the cells and collect between 

 them to form dendritic crystalline aggregations, which are luminous 

 in the darkened field of the polariscope. The lipochromes known 

 at present are red and yellow, the former being styled liporhodine, 

 and the latter lipoxanthine. The reagent for these is concentrated 

 sulphuric acid, whereby they are converted into deep blue acicular 

 crystals of lipocyanine, which remain isolated when derived from 

 lipoxanthine, but arrange themselves in characteristic groups when 

 produced from liporhodine. Illustrations of these will be found 

 in OVERBECK'S (I.) work on this subject. These colouring matters 

 can be extracted from the cultures by means of ethyl alcohol, in 

 which they are just as soluble as in methyl alcohol, chloroform, 

 carbon bisulphide, and benzene. On evaporating the solvent, a 

 fatty mass, furnishing the acrolein reaction, remains behind. This 

 being saponified and salted out with a hot solution of sodium 

 chloride, the liquid underlying the soapy layer will contain the 

 colouring matter, which can then be extracted by shaking up with 

 petroleum spirit and examined spectroscopically. Of these species 

 the following were more closely examined by ZOPF (V.) : Micro- 

 coccus rhodochrous, isolated from the contents of a goose's stomach, 

 is about 0.9 //, in diameter, and will grow on nutrient gelatin, 

 potato discs, &c., to form deep red masses. The absorption 

 spectrum of the liporhodine extracted therefrom shows an ab- 

 sorption band in F. The Micrococcus Erytliromyxa, obtained 

 from the town- water of Halle, has a diameter of 1.0-1.2 //., and its 



