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sects in question are Halobates and Halobato the water-boatmen in shallow, glass dishes of des. ... They feed upon the floating bodies of water, with some of the ooze containing algal dead marine animals, and may be seen to run débris, as suggested by Hungerford, 10 but my out from such objects when alarmed by the ap observations were discontinued before I was proach of a boat. These insects belong to the satisfied definitely that these bugs scooped up Rhynchota (Hemiptera) and in some respects this substance with their front legs, and used it come pretty near to such forms as Hydrometra as food. I also placed back-swimmers of the or Velia.” Walker has found once or twice genus Notonecta in shallow, glass dishes of several specimens of marine Hemiptera belong water and fed them with small crustaceans, ing to the group Halobates, gathered round such as copepods and ostrocods. The backfloating pieces of seaweed, as if obtaining , swimmers appeared to thrive on this food. By nutriment. However, it must be acknowl means of a similar experiment, I was able to edged, that practically nothing is known about demonstrate that the marsh-treader, Hydromthe food of these creatures. McCook? has etra martini, will feed on copepods tangled in demonstrated that individuals of Gerris remi the surface-film. This was more likely to ocgis feed readily on the juice “of finely ground cur when the water became somewhat stale. boiled beef.” They take such food, with avid It is well known that many members of the ity, even in their own habitat.

family Gerridæ, which consists of an assembIf a more critical study should be made of lage of aquatic Hemiptera living on the waterthe food of aquatic bugs in general, in their film, feed mainly on terrestrial insects which various habitats, I believe that still further fall into the water and float on its surface. evidence would be accumulated, showing that Water-striders are considered to be entirely considerable food, of the other kinds, besides predatory in their manner of feeding, and so insects, was used by these interesting forms. far as I know there is no statement to the conIn fact Hungerfords himself has pointed out trary in the literature on aquatic Hemiptera. a number of exceptions, some of which I can However, it may be of interest to state that I substantiate from my own observations, and have definite proof that Gerris remigis and to which I can add others also from my own Gerris marginatus both feed, at times, on veg. observations.

etable matter. The following statement is a The following statements agree with those modified extract, taken from my field notes: of Hungerford to the extent that the aquatic

After having studied water-striders in their bugs now to be mentioned, are not entirely

natural habitats for several months, especially predatory, nor is their food entirely that of in

with reference to their food relations, I desects: I have found by microscopic examina

cided that both Gerris remigis and Gerris mar. tion of the alimentary system that water-boat

ginatus were entirely flesh-eating. However, men of the genus Arctocorisa feed on vegetable

on October 14, 1911, this opinion was changed. matter; diatoms and Oscillatoria have been

At the time, I was making observations of the

water-striders on the surface-film of a brook identified. They probably obtain most of this

near Whiteheath, which is approximately from the ooze on the surface of the mud, at

eighteen miles southwest of Urbana. Small the bottom of the pond or stream. In order to

red fruits were observed, drifting downstream, obtain additional evidence, I placed some of

and these attracted the attention of the water5 Ibid., pp. 380-381.

striders at once. Both species seized them 6"On the Genus Halobates Esch., and Other readily, Gerris remigis with the greater avidMarine Hemiptera, Entomologist's Monthly Mag. ity, and pushed their beak-like mouth-parts azine, Second Series, Vol. IV., p. 231, 1893. through the outer skin, down into the inner 7"Nature's Craftsmen," New York, 1907, pp.

fruit. Some of the fruits, with their attendant 363-365.

water-striders, drifted near the bank of the 8 Loc. cit., pp. 336–337. Ibid.

10 Loc. cit., p. 337.

stream, and with the aid of a large reading matter on pages 473-475, the replacement of glass attached to a pole, it was possible to see a half-tone on page 475, the rectification of the feeding movements of the mouth-parts. page references to illustrations to accord Several observations were recorded later than with the new paging where needed, and readthis of specimens of Gerris remigis sucking justment of the matter from page 571 on, the juices of these berries. Only on one other so as to admit 32 new illustrations of footoccasion was Gerris marginatus seen to use prints and the captions to these.] this fruit as food. The plant from which these This is a work which meets to a gratifying fruits came is commonly known as the coral- degree the need for an essentially non-techberry or Indian currant, Symphoricarpos vul nical treatise upon the natural history of the garis. It is very common along the banks of' mammals of North America. No living person the brook near Whiteheath.

is better equipped to carry to a successful conI have found that, during my observations of clusion such an undertaking than is its author. the food habits of water-striders in captivity, Nelson has contributed in the field of vertewhile confined in aquaria, both species men brate zoology now for over forty years, to be tioned suck the juices of freshly killed Physa explicit, beginning in July, 1876 (Bulletin and Planorbis. They also feed on fresh beef, Nuttall Ornithological Club, Vol. 1, p. 39). on the soft parts of banana fruit, and on the With a background of long experience in the inner, softer parts of the skin.

field, and with further years of official conThese observations seem to add additional nection with the United States Biological Surevidence to Hungerford's11 contention that vey and its unique resources in mammalogy, aquatic Hemiptera are neither entirely preda- he has made available a brochure of pleasing cious, nor do they feed entirely upon insects. amplitude and satisfying authoritativeness. It is very likely that other observers could re Between the colored pictures and the written port further observations of the character that sketches the public can gain from this conhave been recorded here.

tribution a better idea of our principal mamC. F. CURTIS RILEY

mals than from any other available publicaTHE NEW YORK STATE COLLEGE OF FORESTRY,

tion. It should awaken a generally greater AT SYRACUSE UNIVERSITY,

interest in our native mammals, and this will SYRACUSE, NEW YORK

help build up a desire for the conservation of

the harmless and useful species such as has SCIENTIFIC BOOKS

resulted from the public education in relation

to our bird life. On the other hand it is imWild Animals of North America: Intimate Studies of Big and Little Creatures of the

portant to be able to distinguish those mam

mals, chiefly of the order Rodentia, which are Mammal Kingdom. By EDWARD W. Nelson.

thoroughly inimical to human interests. PeoNatural-Color Portraits from Paintings

ple at large must know how to cope with these Louis Agassiz FUERTES. Track Sketches by

enemies. It would seem that a full knowlERNEST THOMPSON SETON. Published by the

edge of the natural history of such animals is National Geographic Society, Washington,

essential to determining the most successful D. C., U. S. A.; 8vo, pp. + 385–612, folded

means of controlling them and to applying frontispiece, 108 colored illustrations on text

these means properly to the varying conditions paper (not plates), 85 halftone illustrations.

throughout the country. Nelson's accounts of [This is essentially a reprint of two articles

our injurious mammals are full of stimulative which appeared in the Nationai Geo

suggestions along these lines, and while the graphic Magazine, for November, 1916, and

work as a whole can not be considered as an May, 1918. The changes comprise repaging

economic” publication, its influence will go beyond page 472, the readjustment of the

far to secure adequate popular consideration 11 Loc. cit., pp. 336–337.

of these matters.

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The species are taken up in groups, in so once assumed the same nearly upright position, far as this can be done safely. Each biog

with its fore feet close to its breast. Both would raphy, of which there are 119, is, as a rule, a

then begin to hop about watching for an opening. composite applying to a number of near-re

Suddenly one would leap at the other, striking with

its hind feet, ... (producing] a distinct little lated forms, thus simplifying matters of pre

thump and the victim rolled over on the ground. sentation, and avoiding repetition. A marked

After receiving two or three kicks the weaker of feature of the book is the degree of concen the combatants would run away. The thump made tration attained; there is no trace of padding, by the kick when they were fighting solved the and no room for baseless speculation, senti mystery which had covered this sound heard rementalizing or humanizing, such as character peatedly during my nights at this camp. ize many current “ nature books. At the The brilliantly coated paper used throughout same time the style is animated and hor this book although hard on sensitive eyes, is oughly entertaining, a gift of composition necessary to the handling of the halftone illuswhich Nelson has exercised in many preceding trations. The printing of both the colored contributions. Here is an instance, unfortu and uncolored pictures in all the copies we nately a rare one, in which a man who really have seen has been done with pronounced sucknows the field has put out a popular book on The color drawings by Fuertes are ada natural history subject.

cess.

mirable and we are astonished at the success Many are the portrayals which are evidently with which this noted bird artist was able to based on Nelson's own personal field knowl turn to mammals, the drawings of which in edge, some of them involving facts here for this contribution mark as far as we know his the first time made known to science. His ac first efforts in the new field. count of the behavior of kangaroo rats in A critical reviewer might succeed in finding Lower California is particularly apt in illus a number of small points to elaborate upon tration of the above statement.

and of which to complain. For instance: It During several nights I passed hours watching

is trite to say that an Alaska brown bear is no at close range the habits of these curious animals.

more an animal than is a house fly. Yet here we As I sat quietly on a mess box in their midst ...

have the title, “Wild Animals of North Amer[they] would forage all about with swift gliding ica,” though there is an evident effort made in movements, repeatedly running across my bare the subtitle to remedy the matter by using the feet. Any sudden movement startled them and all expression, "mammal kingdon." But here a would dart away for a moment, but quickly re taxonomic blunder is tumbled into!. We can turn. ... They were so intent on the food [grains hardly believe that Nelson himself had any. of rice put out for them] that at times I had no

thing final to say with regard to the title page difficulty in reaching slowly down and closing my hand over their backs. I did this dozens of times,

of this book, but that the editor of the Naand after a slight struggle they always became

tional Geographic Magazine got in his work quiet until again placed on the ground, when they

here in the belief so characteristic of editors at once renewed their search for food as though of popular magazines that their public must no interruption had occurred. While occupied be talked down to. in this rivalry for food they became surprisingly But to pin the attention of the reader of pugnacious. If one was working at the rice pile this review upon such really minute defects and another rat or a pocket mouse approached, it would do violence to the facts in the case, immediately darted at the intruder and drove it

which are that, according to the convictions away. The mode of attack was to rush at an in.

of the reviewer, Nelson's “ Wild Animals of truder and, leaping upon its back, give a vigorous

North America ” is more uniformly accurate downward kick with its strong hind feet. ... Sometimes an intruder, bolder than the others,

and at the same time replete with information would run only two or three yards and then sud

along many lines than any preceding book on denly turn and face the pursuer, sitting up on its

American mammals. And even more, it may hind feet like a little kangaroo. The pursuer at

be declared with confidence that this book is

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15

SPECIAL ARTICLES THE SUBSTITUTION OF SACCHARIN FOR

SUGAR IF saccharin can be substituted for sugar it is evident that it must fulfill the functions of sugar and at the same time not produce harmful effects. As a sweetening agent, to be oxidized thereby furnishing energy and to increase oxidation in the body are three functions of sugar. It would seem that saccharin should fulfill admirably the function of sugar as a sweetening agent since it is about 500 times sweeter than sugar. There are some who think that the use of saccharin as sweetening agent is harmful. The extensive investigations of Herter and Folin' for the referee board on the effect of saccharin on the nutrition and health of man show that the amount of saccharin that would ordinarily be used has no deleterious effect. Herter found, in fact, that such enormous doses as 4 grams of saccharin per kilogram of body weight could be given to rabbits without injury. It is recognized that saccharin can not fulfill the second function of sugar named, for it is not oxidized to give rise to energy, but passes through the body almost quantitatively unchanged. The object of the present investigation was to determine if it could fulfill the third function of sugar named, that is, does the ingestion of saccharin increase oxidation in the body. We had already found that the ingestion of sugar, as well as the ingestion of the other food materials, produced an increase in catalase, an enzyme possessing the property of liberating oxygen from hydrogen peroxide, parallel with the increase produced in oxidation, by stimulating the digestive glands, par

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1 Herter and Folin, United States Department of Agriculture, Report 94, 1911.

2 Burge and Neill, The American Journal of Physiology, Vol. 47, No. 1.

Time in minutes.

Fig. 1. Curves showing the increase produced in the catalase of the blood by the ingestion of saccharin and of sugar. The figures (0–180) along the abscissa indicate time in minutes; the figures (0–60) along the ordinate, percentage increase in catalase.

ingestion of food was brought about by the increase in catalase. Our contention that catalase is the enzyme in the body principally responsible for oxidation is further supported by the fact, that by whatever means oxidation is increased in the body, there always results a corresponding increase in catalase, and by whatever means oxidation is decreased, there

much more extensive increase in catalase than did the sugar.

The conclusion is drawn that in addition to being a sweetening agent, saccharin, although not oxidized itself, serves to facilitate the oxidation of the other food materials by stimulating the liver to an increased output of catalase, the enzyme in the body principally responsible for oxidation. Hence, it would seem that saccharin should be positively helpful in the diet, instead of harmful, as some have claimed, particularly in a disease such as diabetes where the principal trouble is defective oxidation.

W. E. BURGE PHYSIOLOGICAL LABORATORY OF THE

UNIVERSITY OF ILLINOIS

results a corresponding decrease in catalase. Stated more specifically, the present investigation was begun to determine if the ingestion of saccharin would produce an increase in catalase, and hence an increase in oxidation in the body just as sugar and the other food materials do.

The animals used were dogs. The sugar used was dextrose, and the saccharin “soluble saccharin,” prepared by the addition of a solution of sodium carbonate to saccharin. The amounts of these substances used were 4 grams per kilogram of body weight of the animal. They were introduced into the stomach of the animal by means of a stomach tube. Determinations of the catalase of the blood from the jugular vein were made before as well as at thirty minute intervals after the introduction of the materials. The determinations of catalase were made by the addition of 0.5 c.c. of blood to 50 c.c. of hydrogen peroxide in a bottle at approximately 32° C., and the amount of oxygen gas liberated in ten minutes was taken as a measure of the amount of catalase in the 0.5 c.c. of blood.

The curve marked “sugar" in Fig. 1, was constructed from data obtained before, as well as at thirty minute intervals after, the introduction into the stomach of a dog of 4 grams of dextrose per kilogram of body weight of the animal. It may be seen that the sugar produced 8 per cent. increase in catalase during the first 30-minute interval; 14 per cent. increase during the 60-minute interval; and 16, 14 and 15 per cent. increase during the succeeding intervals. Two days later, five grams of “soluble saccharin” per kilogram of body weight were introduced into the stomach of the same dog. The curve marked “saccharin" in Fig. 1, shows the results. It may be seen that the introduction of the “ soluble saccharin” increased the catalase of the blood 3 per cent. during the first 30-minute interval; 10 per cent. during the 60-minute interval; 30 per cent. in 90 minutes; 54 per cent. in 120 minutes, and 56 per cent. in 150 minutes. By comparing the effect of the sugar and of the saccharin on the production of catalase, it may be seen that the saccharin produced a

THE AMERICAN ASTRONOMICAL

SOCIETY The twenty-second meeting of the society was held August 20 to 22, 1918, at the Harvard Observatory. Before the gathering it had been expected by many that war conditions would make the attendance so small that it would be scarcely worth while to hold the sessions. As might have been anticipated, however, the number of members of the society residing near Cambridge, together with the staff of the observatory, would make a respectably sized company at any time, and these with the few who were able to attend from a distance made a number which was well up to the average of previous meetings of the society. Although many astronomers about the country are actively engaged in war work, the number of papers presented showed no tendency to decrease, in fact there were the greatest number of communications ever presented at a meeting of the society. This was due primarily to two astronomical occurrences which were not affected by the war, the solar eclipse of June 8, and the appearance of the new star, in Aquila. Each of these events was the occasion of about a dozen papers.

In welcoming the society in his double capacity as host and president, Professor Pickering referred to the last previous meetings at Harvard in 1910, when so many foreign astronomers were present, and he expressed the hope that it would not be too long before similar international meetings of men of science could be held again.

In the intervals between sessions the members were afforded the opportunity to inspect the instruments and work of the Harvard Observatory,

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