In the year 1780, Rombeag noticed a shower of blood that had excited universal attention, and which he could satisfactorily show to be produced by the flying forth and casting of bees, as the phenomenon in the place around the beehives themselves was remarkably striking. From this fact it is evident that the appearance is attributable to other insects as well as the lepidoptera.[761] Bloody rain has also been attributed, with much apparent reason, to other causes still, as the following accounts from reliable authorities show: In 1848, Dr. Eckhard, of Berlin, when attending a case of cholera, found potatoes and bread within the house spotted with a red coloring matter, which, being forwarded to Ehrenberg, was found by him to be due to the presence of an animalcule, to which he gave the name of the _Monas prodigiosa_. It was found that other pieces of bread could be inoculated with this matter.[762] Swammerdam relates that, one morning in 1670, great excitement was created in the Hague by a report that the lakes and ditches about Leyden were turned to blood. Florence Schuyl, the celebrated professor of physic in the University of Leyden, went down to the canals, and taking home a quantity of this blood-colored matter examined it with a microscope, and found that the water was water still, and had not at all changed its color; but that it was full of small red animals, all alive and very nimble in their motions, the color and prodigious numbers of which gave a reddish tinge to the whole body of the water in which they lived. The animals which thus color the water of lakes and ponds are the _Pulices arborescentes_ of Swammerdam, or the water fleas with branched horns. These creatures are of a reddish yellow or flame color. They live about the sides of ditches, under weeds, and among the mud; and are therefore the less visible, except at a certain time, which is in the month of June. It is at this time these little animals leave their recesses to float about the water, and meet for the propagation of their species; and by this means they become visible in the color which they give to the water. The color in question is visible, more or less, in one part or other of almost all standing waters at this season; and it is always at the same season that the bloody waters have alarmed the ignorant.[763] The prodigy, mentioned by Livy, of a stagnating piece of water at Mantua appearing as of blood, was no doubt owing to the appearance of great numbers of the _Pulices arborescentes_ in it.[764]