189 
Scientific Intelligence . — Zoology . 
tonally have only one born, we can very readily believe, be- 
cause such an occurrence is not uncommon among antelopes, but 
it is not natural, being merely the effect of accident ; and as the 
horns of this species are described as being very close upon each 
other, the loss of one of them might easily induce an ignorant 
person, who had seen or procured an animal so mutilated, to 
imagine it a true unicorn. 
41. Cause of the Red Colour of Lake Morat. — Professor 
De Candolle of Geneva lately read to the Helvetic Society of 
Natural Science, a memoir upon the botanical nature of a red- 
dish substance which was observed upon the surface of the lake 
of Morat last spring, and which has attracted the attention of 
the botanists and chemists of Geneva. This substance made its 
appearance in calm weather, and was disposed in large zones 
upon the edges of the lake, especially about the reeds. In the 
different parcels sent from Morat, there w T ere found two distinct 
substances ; !«?£, A greenish fetid substance, leaving when it depo- 
sited the upper part of the water tinged with a red colour ; Qdly, 
A lamellar substance in irregular shreds, of a soft and spongy con- 
sistence. The first of these substances, viewed through a power- 
ful microscope, and minutely observed by MM. Vaucher, De 
Candolle and Prevost, had all the appearance of an oscillatoria. 
The observers even distinctly perceived the motion of this zoo- 
phyte, and the species to which it appeared to come nearest is 
the Oscillatoria subfusca of Vaucher. Compared with this lat- 
ter, however, which M. Vaucher had himself taken at the edge 
of the Rhone, it presented sufficiently distinctive characters to 
constitute a new species. M. De Candolle has named it 0. pur- 
purea. The other substance submitted in the same manner to 
the microscope, presented no traces of organization, and no dis- 
tinct idea could be formed of its nature. Whether it be a zoo- 
phyte of the same family as the last, or merely the remains of 
aquatic plants, it is impossible to decide, without a careful exa- 
mination of it in the spot in which it occurs. The phenomenon 
which has given rise to these inquiries does not seem peculiar to 
the lake of Morat, but is equally observed in other lakes in Swit- 
zerland ; and, it is said, that the fishermen have sometimes ob- 
served it at the upper part of the lake of Geneva. A warm and 
dry season, together with a low state of the water, are the eir- 
