Dr. Livingstone, relating his adventures on Lake Nyassa, says: "During a portion of the year the northern dwellers on the lake have a harvest which furnishes a singular kind of food. As we approached our limit in that direction, clouds as of smoke arising from miles of burning grass were observed tending in a southeasterly direction, and we thought that the unseen land on the opposite side was closing in, and that we were near the end of the lake. But next morning we sailed through one of the clouds on our own side, and discovered that it was neither smoke nor haze, but countless millions of midges, called "kungo," (a cloud or fog.) They filled the air to an immense height and swarmed upon the water, too light to sink in it. Eyes and mouth had to be kept closed while passing through this living cloud—they struck upon the face like fine drifting snow. The people gathered these insects by night, and boiled them into thick cakes to be used as a relish—millions of midges in a cake. A kungo cake an inch thick, and as large as the blue bonnet of a Scotch plow-man, was offered to us. It was very dark in color, and tasted not unlike caviare or salted locust." _A Hundred Stomachs._ Some of the animalcules have in the interior of the body large cavities, which incessantly empty and fill themselves with colored fluid. These cavities represent the heart of large animals and their fluid the blood; and this circulating system is relatively so large that it may be stated, without exaggeration, that some microscopic beings have hearts fully fifty times as large and as strong, in proportion, as that of the horse or ox. A man has only one stomach, whilst invisible microzoa have sometimes a hundred. _Motherly Sacrifice by the Gall Insect._ Some kinds of gall insects immolate themselves in order to protect their offspring. As the enormously distended insect gradually expels its eggs, it heaps them up in a little pile, and when its body is quite cleared out, and only resembles a hollow bladder, the female straightway covers its progeny with it, attaches the edges round them, and dies directly after. It thus forms for them a convex, solid roof, the impermeability of which protects its eggs against the injurious agency of the air and storms. The mother pays for her childbirth with her life, and her young are born under the shelter of her mummified corpse. _Wonderful Spider's Web._