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previously called a new gas-metargon, the supposed traces of which further investigation had shown to be due to some carbon compound. This conclusion has been borne out by Armand Gautier's discovery that the atmosphere contains in addition to carbonic oxide, a hydro-carbon whose composition is not yet known.

Physiology

Of the strictly physiological work that appeared at the beginning of the present century none, perhaps, has excited more interest than the discovery of enterokinase in Pawlow's laboratory in the Institute. for Experimental Medicine in St. Petersburg. This substance is a ferment formed in the secretion of the portion of the intestine lying just beyond the stomach, the duodenum. Its peculiar function is to make active the proteid digesting ferment of the pancreatic juice. Normally it would seem that the digestive secretion of the pancreas, so important in the act of intestinal digestion, is emptied into the intestine in an inactive state. That it may have its proper effect upon the proteid material of the food it must be activated, as the expression goes, by the effect of another ferment, the enterokinase, formed in the intestine itself. The discovery gives us not only a fact of essential importance in the chain of events connected with the digestion of food, and a fact likely to be of importance in the study of diseased conditions, but it also suggests a new idea. The conception that any of the ferments through whose activity the processes of digestion and nutrition are effected may require other ferments, or at least other substances to make them physiologically active, is likely to act as a guiding influence in other investigations. This interesting discovery is only one. of a series that have proceeded from the same laboratory during a number of years, the results of which have been a great increase in our knowledge of the causes producing and controlling the secretion and composition of digestive juices.

The discovery of enterokinase was quickly followed by the publication in England of the important work by Bayliss and Starling on secretin. This substance is formed at the beginning of the intestine by the acid contents of the stomach. It is not a ferment, but a stable substance, which after its formation is absorbed into the blood, carried to the pancreas and excites that organ tc secretion. We have, there

fore, the following interesting chain of events. The emptying of the stomach into the intestine causes the formation of secretin, which in turn produces a secretion of inactive pancreatic juice, and this juice when it reaches the intestine is made active by the enterokinase. We have, as it were, a chemical mechanism which works automatically and serves to explain the timely appearance of the pancreatic secretion at the moment when the food enters the intestine.

A third discovery of this period along the same lines was made in Germany by Cohnheim. He has shown the existence in the walls of the small intestine of a new ferment, crepsin, which has the property of splitting up the peptones (and albumoses) formed from the proteids by the pancreatic secretion. Physiologists have long known that proteids of the food are changed eventually to peptones (and albumoses) during the act of digestion, the change occurring mainly in the small intestine. It has not been known, however, what becomes of this peptone. While presumably it is absorbed into the blood and forms nourishment for the tissues, yet, as a matter of fact, no peptone nor related body can be found in the blood. Cohnheim's discovery is possibly the first step in explaining this matter. Peptones are not found in the blood because during absorption they are broken down to simpler bodies by the erepsin.

The Okapi

That a large animal, hitherto unknown to zoologists, should be discovered only at the beginning of the Twentieth Century is a commentary on the incompleteness of human knowledge. In 1901 the civilized world was given visual evidence of the existence of a mammal. giraffe-like, but belonging to an unknown genus. The Okapi, as the animal is called by the natives of the Congo forests in which it dwells. resembles the horse in its proportions, but its outline is more like that of the tapir. It is as large as a wild horse. The hoofs are cloven. The head is large, with a tapering muzzle. Most unusual is the coloring; for the cheeks are white and the muzzle is brown; the whole forehead is a scarlet patch, which narrows to a thin black line down to the nostrils; the ears, neck, shoulders, belly, and back are of a brown color, which in certain lights gives the effect of crimson; the hind-quarters and hind-legs are striped with purplish black, white, and pale orange,

CHAPTER III

THE WORK OF THE INVENTOR

The original impulse to scientific investigation may have been man's simple curiosity about himself and his environment. But science did not become science until it no longer merited Balzac's sarcastic characterization of it as "a nomenclature "; science did not become science until unto the mere gathering of data was added intuition as to the use and meaning of those data. Like Abt Vogler, with his three sounds, the great scientist, out of his three facts, frames not a fourth fact, “but a star." The ultimate interest of science lies in its factorship in the improvement of the conditions of life.

Science and Our Food

Attention was directed in 1901 to several important applications of science to production-for example, the experiments in breeding new wheats. The Minnesota State experiment station had evolved a wheat which promised to increase the harvest by at least two bushels an acre. Under average crop conditions the new wheat, it was reasoned, should add to the yield of Minnesota and the two Dakotas about thirty million bushels a year. With the price of wheat averaging $.75 a bushel, this increase of yield should mean an increase of the wealth of the three States to the amount of $22,500,000 a year.

The method of breeding a new wheat was described as follows: The pollen from the flower of one wheat was artificially transferred to the stigma of the flower of another wheat, two of the best varieties being chosen-one for the father, the other for the mother of the new wheat. The harvest might prove that the new wheat had some of the poor and few of the good characteristics of the parents; or the new variety might inherit only what was desirable.

Artificial fertilization as conducted in the breeding of wheat is interestingly different from the natural method by which Smyrna fig trees

are made to bear. In 1881 Smyrna trees were imported into the United States and set up in California. But the fruit failed to mature in its new environment. The reason for the failure was suggested by observation of a custom which from ancient times had been followed in the Orient, where, at a certain time of the year, the Orientals plucked the fruit of the wild, or so-called Capri, fig tree, and suspended it in the branches of the cultivated, or Smyrna, fig tree.

Investigation showed that the young Smyrna fig contains only female flowers-the fig being a receptacle, holding flowers which in the ripening fruit become seeds. When the wild figs were hung in the branches of the Smyrna tree there issued from the wild figs a tiny insect, which entered the Smyrna figs and brought them the pollen needed to mature them. It was not until 1889, after many years of experimentation, that the United States Department of Agriculture succeeded in acclimatizing this valuable little insect in California. In 1900 the insects pollenized the Smyrna figs in California, and the result was a crop of figs-fifteen tons were harvested-which experts considered. superior in quality to the imported figs.

Minute organisms, however, play their part in preparing man's food for him not only by their work as fertilizing agents. Certain foods, for example cheese, are dependent for their peculiar flavors upon the presence of bacteria. The "ripening" of cheese is in the first sense a chemical change, but the flavor seems to be due to microbes rather than to the microscopic plants which formerly were given the credit. In Holland the manufacturers of Edam 'cheese have even discovered that they can hasten their processes and make them more uniform by inoculating the milk with whey that contains certain species of bacteria. Since the ripening of cheese is a slow process and different species of bacteria enter into it at different times, scientists have found it difficult to determine the species which bring about particular flavors.

But bacteriology is by no means the only branch of science that aids in improving the methods of production. Without referring in this place to the effects of the discovery of steam and electrical power upon manufacture, it may be noted that the Congress of Applied Chemistry, held at Paris in 1901, considered a plan for the use of electrolysis in the extraction of sugar. M. Dupont, after a series of careful experiments, had made an electrolytic apparatus composed of a wooden vat

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divided into three compartments by porous partitions. Metallic plates served as electrodes, and an electric current of from fourteen to fifteen volts was employed, with a volume of from twenty-five to thirty amperes for each square meter of the anode. The sugar juice was placed in the middle compartment, with water in the two end compartments. In the sugar juice was a plate of lead or aluminum to serve as an anode, while sheet-iron plates in the water-compartments served as cathodes. Under the action of the electric current the albuminoidal matter of the sugar juice was precipitated, leaving the juice clear and colorless, about an hour and a half being required to treat juice containing fifteen per cent. of sugar.

New Phases of Energy

Mention has already been made of the part played by the energy of Niagara Falls in running the machinery of the Pan-American Exposition at Buffalo. The harnessing of Niagara was the largest feat that had ever been attempted in securing electrical power from waterfalls. The majestic cataract had long been the wonder of the traveler, but the idea of deriving from it power on a large scale apparently occurred to few until the late eighties, when several citizens of New York secured from the State Legislature a charter for the purpose. At that time a group of small mills on the bluff below the falls secured some ten thousand horse-power from a thirty-five-foot canal nearly a mile long. The plans of the new company, which was organized in 1889 to work under the charter mentioned above, resulted in the construction of a canal 250 feet wide and seventeen hundred feet long, the water from which was carried to the river below the falls through a tunnel. At the beginning of the century this plant was in operation, with an electrical installation giving fifty thousand horse-power. The water supplied by the canal was sufficient to raise this power by as much. again, when a second power-house, then in course of construction on the opposite side of the canal, should be completed. Schemes were afoot, moreover, for the further utilization of the water.

The commercial and industrial value of this supply of power was recognized. But there were many lovers of nature who protested against the desecration of the great cataract, fearing that a continued. tapping of the waters would so diminish the volume of the falls that