Page:Popular Science Monthly Volume 20.djvu/738

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THE POPULAR SCIENCE MONTHLY.

from which, like the Egyptian towns, it is named, and (as the Egyptians did) it refuses to eat that animal or plant. Further—and this is the essential point of our explanation—among the tribes which act thus, the mother is the permanent element in the family, and the children (as the Egyptians did) derive their names, not from the father, but from the mother's family." Among most of the purest races the various stocks which worship the different animals arc scattered through all the local tribes. But in China, the worshipers of each animal, or at least the people who derive their name from him, are gathered together, as in Egypt, into local aggregates. Thus, the Egyptian marriage customs and the Egyptian animal worship both seem susceptible of explanation as relics of savagery preserved into the midst of civilization by the extraordinary tenacity of Egyptian conservatism.

 

A Glossary of Microbes.—Mr. W. Hamlet gives the following classification of the microbes (microscopic organisms of fermentation and disease): 1. Microbes which appear as points are called monads, monera, or micrococci. They are motionless, and may be regarded as the spores of other microbes. 2. Motionless linear microbes—the Bacteridians and the bacilli. To them belongs Bacillus anthracis. 3. Cylindrical mobile microbes, having rounded ends or contracted in the middle so as to form an 8 are the bacteria proper. Among them is Bacterium termo of putrefaction, the commonest of all. 4. Flexuous mobile microbes. They look and act like eels, and differ but little from the equally active bacteria. They are the vibrios. 5. Spiral microbes, resembling a cork-screw, and mobile; Spirilla spirochetæ. Their presence in human blood appears to be connected with intermittent fever. 6. Microbes with heads, very active, having globules larger and more refractive than the rest of the body at one or both ends. These globules arc apparently spores ready to be detached from a bacterium—Bacterium capitatum. Besides these six principal states, the microbes form agglomerations or colonies that often notably change the aspect of the elementary cells, and which have received various names. Agglomerations in microscopic masses, surrounded by a jelly that sticks them together and deprives them of motion, are called zoöglæa. A non-gelatinous membrane formed of motionless bacteria is a mycoderma. Bacteria attached end to end in a string form filaments of leptothrix. A number of spherical micrococci joined one after another form the string of round grains called a torula. A considerable number of species may be included in each of these divisions; and there does not appear at present any way to distinguish by sight a disease-producing bacterium from a harmless one.

 

Circulation of Blood in the Brain.—Signor Mosso, who has been engaged on the subject for six years, has published some new observations on the different conditions of the circulation of the blood in the brain. He has had the privilege of observing three patients who had holes in their skulls, permitting the examination of the encephalic movements and circulation. No part of the body exhibits a pulsation as varied in its form as the brain. The pulsation may be described as tricuspid; that is, it consists of a strong beat, preceded and followed by lesser beats. It gathers strength when the brain is at work, corresponding with the more rapid flow of blood to the organ. The increase in the volume of the brain does not depend upon any change in the respiratory rhythm; for, if we take the pulse of the fore-arm simultaneously with that of the brain, we can not perceive that the cerebral labor exercises any influence upon the forearm, although the pulsation in the brain may be considerably modified. The emotions have a similar effect upon the circulation of the brain to that of cerebral labor. Signor Mosso has also observed and registered graphically the variations of the cerebral pulse during sleep. Generally the pulses of the wrist and the brain vary oppositely. At the moment of waking, the pulse of the wrist diminishes, while that of the brain increases. The cerebral pulsations diminish as the sleep grows deeper, and at last become very weak. Outward excitations determine the same modifications during sleep as in the waking state, without waking the sleeper. A deep inspiration always produces a diminution in the volume