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Continuously Deflecting Pyrovolter

A millivoltmeter containing Pyrovolter circuits for checking its indications on a potentiometric principle.

In this manner, the many varied and subtle disturbing sources of error involved in the resistance changes of the thermocouple (or unknown E.M.F.) circuit are eliminated.

This elimination of error, combined with simplicity of principle and operation, and sturdy construction, render the C.D. Pyrovolter a valuable instrument, where accurate electrical potentiometric measurements of small E.M.F.'s are to be made.

In short-in the C.D. Pyrovolter there is

the simplicity of the millivoltmeter

combined with

the accuracy of the portable potentiometer
Write us for further particulars, requesting Circular 15

PYROLECTRIC INSTRUMENT CO.

636-640 East State St.

TRENTON, N. J.

E. F. Northrup, President and Technical Adviser

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Your Vacation
Opportunity

The Summer Quarter 1919 will receive the added in-
spiration of professors and instructors returning from
war service in many lands. Students and teachers,
interested in keeping abreast of the times or in com-
pleting work already begun, appreciate the opportunity
of instruction in a regular season of study under mem-
bers of the University staff. Scholars desiring to pros-
ecute research in the libraries and laboratories will find
facilities for work under the most favorable conditions.
Courses are offered in all departments and include
undergraduate and graduate instruction in Arts, Liter-
ature, Science, Commerce and Administration, Law,
Medicine, Education, and Divinity.

SUMMER QUARTER 1919

First Term June 16-July 23
Second Term July 24-August 29

Students may register for either term or both

For the complete announcement of courses address

The University of Chicago, Chicago, Ill.

Materials
Fresh Water
Terrestrial
Marine

Insects
Frog

Snake

Turtle
Fish

Catalog A

Catalog B

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OUR SERVICE IN SUPPLYING

LABORATORY APPARATUS
GLASSWARE AND

SUPPLIES

has given entire satisfaction to so many laboratories. Numerous testimonials have reached us and our prompt and efficient service invites similar expressions from our new

customers.

Due to favorable connections with leading manufacturers, supported by a large stock, stored in our warehouse, we can offer prompt delivery. Our product is of foremost quality only and protected by the guarantee of our reputation.

Our staff has been trained in the scientific application of most of the apparatus and instruments; which fact assists us to make our service satisfactory.

With the aid of our mechanical and optical manufacturing departments we can attend to the construction, as well as to the repair of scientific apparatus, in accordance with the specifications of our patrons, and we know that this service has been appreciated very much by our clients.

Upon receipt of a list of your laboratory re-
quirements we will submit our estimate
promptly and we are confident that our prices
will prove interesting to you.

Catalogs and supplementary publications will be furnished
upon request; in your application please refer to "O-10."

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YORK NEW YORK NEW YORK

SUGARS

FOR USE IN BACTERIOLOGY

DEXTROSE, Bacto, "Difcos," a carefully tested and uniform product, free from all other sugars and from starch, proteid, alcohol, and heavy metals.

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DEXTROSE, Mulford, Pure, specially prepared for bacteriological work.

Per 50 gram package.
Per 250 gram package
Per 500 gram package

1.25

2.45

.4.80

1.25

5.25

..10.00

GALACTOSE, Bacto, "Difco," with low moisture and ash content, specific rotation

80.5, purity 99+%

Per 10 gram vial..
Per 1 oz. package.

INULIN, Mulford, specially prepared for bacteriological work.

.75

2.00

2.75

Per 10 gram package. Per 100 gram package....25.00 LACTOSE, Bacto, "Difco," guaranteed free from Dextrose. A very fine, pure white powder, free from odor and completely soluble in water.

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LACTOSE, Mulford, pure, free from Dextrose, specially prepared for bacterio

logical work.

MALTOSE, Bacto, "Difco"

RAFFINOSE, Bacto, "Difco"

SACCHAROSE, c.p., Baker Analyzed

SACCHAROSE, Merck white label

SALICIN, for use in work on streptococci
XYLOSE, Bacto, "Difco"

2.50

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Prices subject to change without notice

ARTHUR H. THOMAS COMPANY

IMPORTERS - DEALERS-EXPORTERS

LABORATORY APPARATUS AND REAGENTS

WEST WASHINGTON SQUARE

PHILADELPHIA, U. S. A.

SCIENCE

FRIDAY, APRIL 11, 1919

CONTENTS

The Unification of American Botany: Dr. G.

R. LYMAN

339

The Elementary Course in Zoology-is it satisfactory? PROFESSOR C. E. MCCLUNG ..... 345

Wallace Clement Ware Sabine

Scientific Events:

The Gaspé Bird Reserves; Reorganization of the Farm Management Office; Corporation Chemistry; Memorial Professorship to Dr. James Jackson Putnam

Scientific Notes and News

University and Educational News

Discussion and Correspondence:—

Patent Reform Prospects: BERT RUSSELL. Dr. Moodie's Opisthotonus: PROFESSOR BASHFORD DEAN. A Standard Scientific Alphabet: A. FANTI. Field Work in Arizona: F. M. PERRY

Quotations:

Science in the British Parliament

Scientific Books:

Contributions to Embryology: PROFESSOR FREDERIC T. LEWIS

Special Articles :—

THE UNIFICATION OF AMERICAN

BOTANY1

now

A GLANCE at the history of botany in America shows that on several occasions special branches of the science have attained prominence, have separated from the parent stock and taken independent root. These offspring are counted as separate sciences which yield little or no allegiance to the parent stock, and whose : 47 devotees no longer call themselves botanists. As examples we may mention bacteriology, forestry and the group of agricultural sciences represented by agronomy and horticulture-all subjects essentially botanical, with large and active corps of workers, but belonging to botany no longer.

350

353

355

356

358

359

The Technique of Solution Culture Experiments with Plants: DR. D. R. HOAGLAND. Unheated Egg-yolk Media: G. F. WHITE... 360

MSS. intended for publication and books, etc., intended for review should be sent to The Editor of Science, Garrison-onHudson, N. Y.

Are

This dissociation is undoubtedly the natural result of the growth of botany and the development of its several fields, each of which, as it assumes a position of special importance, develops more or less of autonomy and sometimes independence. Other sciences show the same tendency, and I shall not attempt to decide whether botany shows this trend toward dissociation to an exceptional degree. The questions of immediate importance to us are: What are the causes of this dissociation? they still operative? What new developments may be expected? How far can the process go without serious injury to botany in general? Can the tendency be overcome in whole or in part? And if so, how? It is fitting that these questions should receive the serious consideration of all botanists at this time for the future is heavy with possibilities. The changes of reconstruction may prove to be more fundamental than those of war, and the responsibility

1 Invitation paper before Section G of the American Association for the Advancement of Science, in joint session with the Botanical Society of America and the American Phytopathological Society, Baltimore, December 26, 1918.

for American botany during this period of flux rests upon the botanists themselves.

That the tendency amongst botanists toward dissociation is too strong to be disregarded is shown by an examination of the recent botanical programs of these winter meetings in comparison with those of a few years ago. Formerly all botanists met with Section G of the American Association for the Advancement of Science, and with the Botanical Society of America for the reading of papers on miscellaneous botanical subjects. Now, the plant pathologists, the geneticists and the ecologists have independent societies; the physiologists and systematists have separate sections of the Botanical Society with independent programs; and still other groups of botanists are beginning to request recognition and to urge that 'special sessions be devoted to their subjects. The grouping of papers according to subject matter and the formation of special programs are made necessary by the rapid increase in the number of papers presented, and doubtless are desirable in every way. The formation of different sections by the Botanical Society of America, and even the launching of independent societies by various groups of botanists, are the natural results of rapidly mounting numbers and of increasing specialization.

There is no question but that the evolution of our winter programs indicates healthy growth, yet we must recognize the lurking danger, for we see here one evidence of the centrifugal tendency amongst botanists. Separate programs denote and foster a concentration of effort along special lines. They are one sign of our inclination to segregate into groups, the special subjects in which we are interested acting as the foci of attraction. This segregation, within proper limits, undoubtedly makes for efficiency, but we must take care that it does not lead to undue slackening of interest in other botanical fields than our own, to loss of perspective and to inability to grasp other points of view. If this occurs we shall have crossed the danger line, ultimate estrangement amongst botanists becomes a mere matter of time, and efficiency will give place to disunion and narrowness. Botanical science could not

then be compared with a healthy tree surrounded by vigorous offspring in the shape of subsciences; rather would it be likened to an ancient trunk denuded of many of its most important branches which have struck root for themselves and are now selfishly competing with one another and with the impoverished parent stem.

Our problem then is to preserve the unity of American botany without losing the benefits of specialization. It is the old problem of controlling and directing the vital forces which underlie growth and development that they may make for efficiency and strength rather than for disunion and weakness.

I believe there is one factor more potent than any other in promoting disunion amongst botanists. That factor is not the fundamental scientific importance of a given field of botany, nor the speed of its development. We have seen the rise to importance of one subject after another without witnessing their withdrawal from the botanical hearthstone. It is not the development of a peculiar and highly specialized technique, nor the concentration of interest in a particular group of plants. Neither is it mere number of workers in a given field, nor close affiliation with non-botanical subjects. All these factors contribute to dissociation within the ranks of botanists, but do not necessarily lead to rupture of those ranks. Perhaps not all combined are so potent in this respect as is economics. Whenever any branch of botany becomes of especial economic importance its centrifugal tendency is enormously increased. The general public is then interested and becomes instrumental in determining the course of development. There is a new and greatly enlarged staff of workers, many of whom have not received orthodox botanical training. These workers in the new field of applied botany lose the isolation of the pure scientist, and come more closely in touch with the problems of human life. New methods of thought appear and new standards of value arise. While the applied botanist is developing the ideals of service to his fellow men, he often over-emphasizes the importance of his own field, loses his catholic interest in botany in

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