COLOURING MATTER DECOMPOSITION OF OSCILLARIAS. 337 
play an important part in the production of this colouring 
matter. But it is proved at the same time by the experiment 
upon the cercaria which has been mentioned above, that mat- 
ter purely animal, evincing, as in this case by the green co- 
lour, a still greater resemblance to those algse which are most 
consistent, is not fitted for the production of this colouring 
material. 
Several other specimens of confervse obtained from Aix la 
Chapelle, in a perfect state of preservation, were recognised 
as belonging to oscillaria vivida (Agardh,) a species closely 
allied to 0. limosa. But certainly the warm springs of Aix 
la Chapelle must contain numerous other species of the same 
genus. 
The subject which has just been considered, important as 
it is, connected with the astonishing group of oscillarias, which 
seem to be the link between vegetable and animal life, can, 
moreover, assist in the explanation of the phenomenon termed 
blood-like water, bloody rain; and upon which, a most meri- 
torious naturalist, Professor Ehrenberg, has lately presented 
so complete a memoir. In it we are informed of all the infu- 
sorise variously coloured red, and of the minute plants of the 
families fungi and algae, which have been considered the cause 
of blood-like water. 
The observation of M. Nees d'Esenbeck, is distinguished by 
the difference of colour, according to the direction of the light, 
and by the causeof its production, the decomposition of the algae. 
To the same cause must be attributed the blood-like water of 
Lake Lubotin, examined by Klaproth; at least, the description 
of this water, and its chemical properties, exactly resemble 
those of the water experimented on by M. Nees d'Esenbeck, 
and the myriophyllum spicatum, which is presumed to be the 
cause of this phenomenon, can have but little part in its pro- 
duction. 
Another similar investigation is that of Vauquelin, upon a 
substance derived from the spring of Vichy. The liquid, of 
which this chemist speaks, does not differ from the reddened 
VOL. II. — NO. iv 43 
