From the October 3, 1931 issue


When Darwin, as a young naturalist just out of school, visited the Galpagos islands, he saw a number of things that helped to crystallize and precipitate in his mind the concept, already seeded there, that later revolutionized all biology and much of philosophy. Not the least provocative of speculation was a most peculiar species of sea-going lizard, the marine iguana that basked–and still does bask–in thousands on the sun-warmed rocks, slipping off into the water betimes to browse on the thick-growing seaweeds.

Reptiles, Darwin knew, are predominantly dry-land and fresh-water inhabitants; very few of them brave the sea. Big marine turtles are the most successful; there are also a few crocodilians and one small group of snakes; finally, these odd iguanas. How land-bound even these latter are in their instincts can be discovered when they are frightened. Instead of swimming out into deeper water when danger threatens, they scramble for shore. Pick one of them up by the tail and fling him out to sea, and he immediately comes back almost to your feet!

Yet the marine iguana also shows his own adaptations for a life, if not on the ocean wave, at least beneath it. Most of his kin have all sorts of frills, dewlaps, and other excrescences that would be as much in a saurian swimmer’s way as puffed sleeves on a bathing suit would be in the way of a human mermaid. But the marine iguana affects a stern and Spartan economy of profile; all that he retains of the heritage of his race are knobby spines on his head and the waving digitate frill down his back; and even this last is cropped close.


Demonstration that the germ of smallpox is probably a minute spherical body one hundred-and-twenty-five-thousandth of an inch, or one-fifth of a micron, in diameter, near the lower limit of microscopic visibility, was announced before the meeting of the British Association for the Advancement of Science by Prof. J.C.G. Ledingham, director of the Lister Institute of London.

This climaxes the medical war against smallpox, which began with Jenner’s discovery of vaccination, long before Pasteur founded bacteriology. Although smallpox has been a disease absolutely controlled for decades, incongruously enough its causative organism has been heretofore unknown. For a quarter of a century, minute spherical bodies have been found in certain virus diseases, such as smallpox and cowpox, but these have always been ignored. Their agglomerations constitute large inclusions which are striking features in the body cells and in the pox lesions of patients.


There were snails on Earth half a billion years or more ago, in the time known to geologists as Lower Cambrian. Their shells have not yet been found as fossils, but they left their tracks on the silts and sands of that ancient world that have since hardened into rock.

These tracks have been known for a long time, but have always been credited to worms. But recently two geologists, Dr. and Mrs. Carroll Lane Felton, made a critical study of snail tracks on the seashore and compared them with the ancient tracks on their stone specimens. Their conclusion is that the tracks are much more like those of modern snails than they are like any other animal trails.

To the objection that no snail shells have yet been found in Lower Cambrian fossil beds, they point out that it is not necessary to find any, for many species of snails known today are shell-less.

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