236 
MEMORANDA. 
themselves^ or are the result of imperfect drawings I am not 
able to say ; most probably the latter. — George Hunt, 
Handsworth, Birmingham. 
The "Rio de Sangu." — At the meeting of the Academy 
of Sciences in Paris, held October 6th, 1856, M. J. 
Rossignon read a note on the Rio de Sangu^^ (River of 
Blood), in the territory of Honduras. The account of this 
extraordinary phenomenon, which to us appears scarcely 
credible, is as follows : 
" This singular spring is found near the village of La 
Virtud, near Choluteca, between the states of Salvador and 
Honduras. 
The slender thread of water of which the spring is com- 
posed, flows constantly from a grotto formed of trachitic 
rocks. As it escapes from the source, the liquid presents 
the bright red hue of the blood of an animal recently killed. 
Its density is 2*75, and it has no sensible smell or taste. At 
a short distance, however, from the grotto it soon becomes 
changed, doubtless owing to the action of light, and above 
all to that of heat, which is very considerable in that country. 
It then acquires the smell of putrid flesh, which attracts the 
black vultures (zopilotls), the natural scavengers of those 
tropical regions, and who, when they have nothing better to 
devour, content themselves with this meagre diet. 
The liquid is coagulated by acids, and the coagulum i» 
redissolved by alkalies. Evaporated in a capsule, it first coagu- 
lates at a temperature of 80° cent., and then throws down a 
deposit, which readily swells up and assumes a reddish-black 
colour. Distilled in a close vessel this residue afibrds all the 
products of the decomposition by heat of animal substances, 
leaving a porous and very friable, azotized charcoal. It 
aflbrds at the same time an ammoniacal, yellowish oil of 
nauseous odour, but which differs widely from the animal 
' oil of DippeL' 
M. Bossignon detected in this fluid a great number of 
infusory animalcules, having an elongated form, and to which 
he attributes its colour and peculiar properties. 
*^ M. Bossignon has also observed, in the small streams in 
Guatemala, vermiform animalcules, moving with excessive 
rapidity, and decomposing very speedily after the water 
had become stagnant. This water soon acquires a reddish- 
brown colour, exhales a very strong putrid odour, which 
also attracts the vultures and other carnivorous birds. The 
author of this memoir has detected, under several other cir^ 
cumstances, in stagnant waters more or less coloured, ani* 
