of a Lake near Lulotin^ in South Prussia, 94f 



«nly became perfectly clear and colourless, but the caseous 

 ilakes which were separated appeared of a pale whitish 

 yellow. 



8th. Oxygenated muriatic acid destroyed the colour com- 

 pJetely ia the course of a few seconds. The water remained 

 ibr some time turbid and whitish: when, exposed to heat it 

 suffered yellowish flakes to be deposited. 



9th. By caustic alkali the colour of the water imme- 

 diately became brownish. A few gray flakes were deposited; 

 the greater part of wliichj however, were afterwards dis- 

 solved. When the clear solution v/as neutralized by mu- 

 riatic acid, the part dissolved in the alkali was again sepa- 

 rated in soft yellowish gray flakes. 



These results are suthcient to enable chemists to deter- 

 mine with certainty the nature of the matter contained in 

 this water. It consists of those component parts com- 

 monly comprehended under tlie name of the albuminous 

 principle, and which in the present case served as the basis 

 of a peculiar colouring matter of the nature of indigo. This 

 vegetable albumen which is contained in a great many 

 plants, and to which belong those component parts of ve- 

 getables known under the names of gluten, materia vegeto-^ 

 aTiimdl'is, Sec, is, in regard to its component parts and 

 chemical properties, of an animal nature, and has a near 

 aflinitv to annual albumen, the caseous parts of milk, and 

 the curdled part oi serum. If those plants which amono- 

 their intimate component parts contain this albuminous 

 matter are abundant at the same time in colouring matter, 

 the latter is connnonlv in close union with the former. We 

 have an example of this in indigo, the basis of which is of 

 the same nature as albumen. 



The dispersion in water of this colouring matter, com- 

 bined with albumen, can take place only at periods when 

 the plants, to the component parts of wliich it belongs, 

 arc in a state of solution and decomposition by desiccation 

 or putrefaction. The phccnomenon, therefore, cannot be 

 observed in summer, when the plants are alive and in a 

 ftate of vegetation, but only in winter, when they are 

 dead. By the successive decomposition of the dead plants 

 imdrr the water, the extractive matter, and such of its com- 

 ponent parts as are susceptible of complete solution in that 

 fluid, pass into it. The albumen is at first received by the 

 water, but ii docs not enter into a constant, but only ap- 

 parent and mvchanical, solution; the particles exercise a 

 nuitiial attraction, approach each other, and in that state 

 tjrm a flaky accumulation wliich floats on the water till 

 Q4 Uicy 



