From the July 10, 1937, issue
EGGS OF OPOSSUM PHOTOGRAPHED TO SHOW EARLIEST LIFE STAGES
Eggs of a very primitive type of mammal, the common American opossum, have been studied and photographed by Dr. Carl Hartman and his associates of the Department of Embryology, Carnegie Institution of Washington, D.C., in their Baltimore laboratory. They have succeeded in obtaining these early life stages at several points of development, from unfertilized and just-fertilized eggs to the earliest divisions of the body into the beginnings of nervous system, muscles, etc.
It takes trained eyes and critical searching to find the eggs in their first, unfertilized state. They are then only about the size of poppy or tobacco seed, and of just about the same color as the much-wrinkled walls of the uterus, or reproductive cavity, into which they have been discharged from the ovaries. Yet careful hunting succeeds in locating them, and equally careful gathering methods get them out.
Immediately after fertilization by the spermatozoa, the eggs enlarge rapidly to several times their original diameter, and become somewhat clearer in appearance. They are then said to be in the primary vesicle stage.
On the surface of the vesicle appears a scarcely visible white line or streak. It is caused by a thickening or condensation of the living, actively growing protoplasm, and is known as the primitive streak. It is a sort of architectural chalk line, showing where future building is to take place, for it marks the site where the new animal’s body will begin to develop.
One of the most interesting of Dr. Hartman’s photographs shows a group of 22 cells at this early stage of development. Seven of them have been fertilized and have grown normally; four, though fertilized, show dwarfed or retarded growth; eleven remain unfertilized and show no growth or development at all.
ODD-SIZED SUBATOMIC UNIT SUGGESTS UNIVERSE NOT UNIFORM
That the universe may not be uniform with regard to the fundamental building blocks of matter is hinted in the report on a recently detected particle in cosmic rays, presented by Dr. J.C. Street of Harvard University to the American Association for the Advancement of Science meeting in Denver. From beyond the Milky Way are imported as part of the cosmic rays constantly penetrating particles not found on Earth. They are responsible for the showers in the cosmic rays. The new particle is five to fifty times heavier than the familiar unit of electricity, called the electron, but it carries the same electrical charge.
Magnetic storms here on Earth cause a variation in the intensity of cosmic rays recorded on delicate instruments, Dr. R.D. Bennett of the Massachusetts Institute of Technology reported.
A year-round cosmic-ray recorder will be installed in America’s highest scientific laboratory on the 14,256-foot peak of Mt. Evans near Denver, Dr. Joyce C. Stearns of the University of Denver announced. The high-altitude laboratory, built to withstand winds of 150 miles per hour, begins its second summer this season. The question as to whether cosmic rays can affect the course of evolution will also be studied by exposing fruit flies on the peak this summer.
APES TAUGHT TO USE GESTURES TO ENLIST AID IN JOINT TASK
What means of communication do chimpanzees have?
That is the question scientists are asking themselves as a result of experiments just reported by Dr. Meredith P. Crawford of Yale University’s Laboratories of Primate Biology.
Neither circus man nor scientist has ever been able to teach an ape to speak, despite the fact that the chimpanzee, nearest kin to a man, appears to be endowed with all the necessary vocal apparatus and perhaps with sufficient intelligence to make speech a possibility for him. What he may lack is, surprisingly enough, the ability to ape sounds. With the ape, it is a matter of “monkey see, monkey do.” What he hears, he does not try to imitate.
If chimpanzees ever learn a language, it most probably will be a language of gestures such as that used by deaf-mutes among the human family, so the students of these animals have predicted.
Now Dr. Crawford reports what may be a beginning in this direction!
Compelling gestures that induce another chimpanzee to leave her play and do her share in a common task have actually been learned and used by chimpanzees under Dr. Crawford’s instruction. This may not be language as the human knows it, but it certainly serves as a means of communication between apes, understood and acted upon by them.
