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upon opening the shell, and, on candling such eggs after sealing, it is found that the size of the air chamber remains unchanged. With the old method we frequently had a mortality of 50 per cent or higher in the first twentyfour hours. With the new method the deaths during the first twenty-four hours are reduced almost to zero.

Embryos may die three to five days after the operation and for these later deaths we have not yet found the cause or causes. ELIOT R. CLARK

UNIVERSITY OF MISSOURI

THE AMERICAN CHEMICAL SOCIETY.

VIII

The composition of okra seed oil: GEORGE S. JAMIESON AND WALTER F. BAUGHMAN. (By title.) Several lots of the seed of the okra (Abelmoschus esculentus) were received at various times from E. A. McIllhenny of Avery Island, Louisiana. The seed were found to contain about 15 per cent. of oil. The oil expressed from the seeds by means of the expeller had a greenish yellow color. The results of the analysis of the four expressed okra seed oils are given in the following table:

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The composition of the oil from the seed of the Hubbard squash: WALTER F. BAUGHMAN AND GEORGE S. JAMIESON. (By title.) The oil for this investigation was expressed from the seed of the Hubbard squash (Curcurbita maxima) by means of the expeller. A portion of the oil was refined by the well-known alkali process and bleached with fuller's earth. The crude oil had a brownish red color and the refined portion had a yellow color. Both crude and refined oils had a bland fatty taste. The following are the chemical and physical characteristics:

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protein nitrogen compounds which give much trouble in the defecation of the juice for sirup. 1-leucin, d-1-asparagin, glutamin and aspartic acid have been identified. The acids found in the juice are aconitic, citric, oxalic, tartaric and malic. The hexoses decrease, and sucrose increases, as maturity approaches. In northern-grown cane the sucrose-hexose ratio is considerably lower than in southern-grown cane, and the total sugars are also much less. During the pre-maturation period the sorghum plant lays down a protein-cellulose framework, which is filled in with carbohydrate during the final maturation period. This carbohydrate is starch in the case of the seed head, and sucrose in the stalk. The removal of the seed heads prior to maturity hastens the production of sucrose in the stalk, but does not affect the total amount formed.

The physiology of germinating Juniperus seeds: D. A. PACK. (By title.) The Juniperus seed fails to germinate when put under ordinary germinating conditions. The changes, that prepare this seed for germination, are brought about by storing at 5° C. These changes are characterized as follows: an early and complete imbibition of water; a slow increase of the H+ concentration and total acid; evident changes in the stored food material; very slight increase of the respiration and oxidase activity; slow enlargement of the embryo with the development of internal stress; steady decrease in the viscosity of the seed coat; marked increase in catalase activity; and an increase in the vitality of the seed. A good percentage of germination follows at once upon the completion of these changes.

The biochemist on the hospital staff: FREDERICK S. HAMMETT. The paper pointed out the advantage which would accrue to medicine if the hospital biochemist were regarded as a coordinate member of the hospital staff, a specialist in a special field, rather than as a mere technician who makes routine analyses.

A spectrographic study of certain biochemical color reactions: G. L. WENDT AND T. TADOKORO. (By title.)

Studies of wheat flour grades. I. Electrical conductivity of water extracts: C. H. BAILEY AND F. A. COLLATZ. (By title.) The studies previously reported by one of us (SCIENCE, Vol. 47, pp. 645647) were continued, and it was found that time and temperature of extraction affected the electrical conductivity of water extracts of wheat flour. The conductivity increased with the period of extraction, the proportional increase being

greater when the extraction was conducted at lower temperatures, and also with the lower grades of flour. The relative conductivity increased as the temperature of extraction was raised above 0° until 60° was approached, when it began to diminish. A standard procedure was adopted for comparing a number of flours containing from 0.40 per cent. to 2.38 per cent. of ash. The flour: water (1:10) mixture was held at 25° for exactly 30 minutes, centrifuged, and the conductivity of the clear liquid determined by means of a dipping electrode constructed for the purpose. When examined in this manner a remarkably close parallelism was observed between the conductivity and the ash content.

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Studies of wheat flour grades. II. Buffer values of water extracts: C. H. BAILEY AND ANNA PETERSON. (By title.) The hydrogen-ion concentration of water extracts of various grades of wheat flour varies between rather narrow limits. Flours with an ash content of 0.45 per cent. yielded an extract (prepared by extracting a 1:5 mixture for 60 minutes at 25°) of Ph=6.1, while the extracts of flours containing from 1.2 per cent. to 1.6 per cent. of ash had a Ph about 6.4. The buffer values of the extracts of these flours varied greatly, however. Thus the addition of 10 c.c. of N/50 NaOH increased the Ph of patent flour extracts 3.3 (i. e., to about 9.4) while the extract of lower grades was increased in some instances only 0.6 to .9 in terms of Ph. The increase in Ph is thus inversely proportional to the ash content, and the ratios are quite exact. The buffer value of extracts uniformly prepared is indicative of the grade of sound flours milled from normal wheat.

The preparation of certain monocarboxylic acids from sugars: I. K. PHELPS AND W. T. MCGEORGE. CHARLES L. PARSONS, Secretary

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SCIENCE

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SEXUALITY IN MUCORS1

THE keywords of the vice-president's address and the symposium which followed it last year were Organization, Coordination and Cooperation in botanical research. It is not my purpose at this time to discuss these topics further. A botanical committee of the National Research Council has been selected for this purpose. A second committee was chosen by the Botanical Society of America two years ago to help the first committee and last year a third committee was appointed to help the other two. The organization seems sufficiently complete unless I might suggest as a humble member of this last-named committee that a new committee be formed at this session to help us also in our deliberations which have not as yet taken place.

One of last year's speakers, in distinguishing types of true research worth while from investigations unworthy of the name, held up to ridicule a hypothetical investigation of a ham sandwich and the pseudo-scientist who would attempt a monographic treatment of such a subject. In defence of the maligned sandwich, a correspondent has offered the following lines:

Sandwich perched by the lunchroom wall, I lift you down from the perches. Hold you here, ham and all, in my hand. Little sandwich! But if I could understand What you are, ham and all, and all in all, I should know what true research is. It is not of so broad a subject as the sandwich in its entirety, neither of the ham nor of the bread between which it nestles that I wish to speak. Rather it is the mold that sometimes grows on the bread that encircles the ham, or more especially the less commonly 1 Address of the vice-president and chairman of Section G, Botany, American Association for the Advancement of Science, St. Louis, December 30,

1919.

observed sexual reproduction of the bread mold and its relatives that I have chosen as my theme.

It will not be possible in the time available to enter into any detailed discussion of many questions that might suggest themselves in this connection. I shall instead give an outline merely of some of the investigations of the last fifteen years, both published and unpublished and shall attempt to show that the sexual relations of the mucors may have possible bearings upon our conceptions of sexuality in other diverse groups of the biological world.

The chart (9, Tafel VI.) shows the typical vegetative condition of a mucor. A vegetative spore, usually multinucleate though sometimes uninucleate, sends out in germination a branching tube which forms the mycelium and rapidly covers the available substratum. This mycelium is multinucleate and, in the early stages at least, without cross wallsforming thus an enormous, much-branched, single cell-if a cell is defined in terms of the limiting cell walls. Multiplication is brought about chiefly by various types of nonsexual spores. The commonest are endogenous spores produced in sporangia, upwards of 70,000 individual spores being formed in a single sporangium. They may be apparently exogenous, formed singly or in chains on terminal swellings of fertile filaments and may be produced as chlamydospores by septation of the vegetative filaments. More than a single type of nonsexual multiplication may occur in a given species.

As regards their sexual reproduction, there are two groups of species. In the first group, represented by Sporodinia, a form common on fleshy fungi, the sexual spores known as zygospores are common and may be obtained from the sowing of a single vegetative spore. Such forms are therefore hermaphroditic or homothallic since their thalli or mycelia are alike sexually. In the second group, repre

2 Citations in parentheses throughout the text refer to the sources for the charts and lantern slides used in the original presentation of this paper.

sented by Rhizopus, the bread mold, the zygospores are rarely observed and can never be obtained in pure cultures from the sowing of a single spore. In these diecious or heterothallic forms there are needed two plants of opposite sex growing in contact in order that sexual reproduction may take place. The two sexual groups mentioned are represented in the adjoining diagram (Fig. 4). Since in the three lower figures the two gametes (which later unite to form the mature zygospore) arise from branches of a single filament, these three forms are hermaphroditic. In the upper figure the gametes are represented arising from sexually different plants designated by the signs plus and minus which will be explained later. These therefore belong to the diecious group. The line of zygospores, which results when the opposite sexes of the diecious species Mucor Mucedo are grown in contact, is shown in the chart. The swollen heads produced on erect filaments from the plant on the right of the line are sporangia containing numerous nonsexual spores by which the plant may be propagated as distinct sexual races in much the same manner in which races of potatoes may be propagated by non-sexual tubers. The process of conjugation may be followed from the figures in the chart (9, Tafel VII.). Filaments of opposite sexual tendencies grow together and by the stimulus of contact produce swellings which push them apart. These swellings develop into the progametes from which by cross walls the sex cells, or gametes, are cut off. The dissolution of the intervening cross wall allows a fusion of the gametes and the zygote thus formed increases in size and becomes the mature zygospore. The gametes are typically equal in size in the diecious group and also in the hermaphroditic group except for certain forms to be discussed later. They are miltinucleate and hence have been called cœnogametes.

In the first lantern slide (1, Pl. IV.), we can see photographs of Petri dish cultures of certain of the mucors experimented with. The opposite sexes of the diecious species have been termed plus and minus for reasons

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sidered minus. A microscopic investigation of the appearance of the white lines of sexual reactions shows the condition represented in Figs. 36-39 (1). The stimulus of contact leads to the formation of progametes. Sometimes the gamete is formed by one and more rarely by both the reacting filaments. In one strong reacter the gamete which is formed in this reaction transforms itself frequently into a thick-walled a-zygospore. The stimulus which leads to a dissolving away of the wall between the two gametes and their consequent fusion is constantly lacking. Since the sexual reaction between opposite sexes of different species is incomplete it has been termed "imperfect hybridization."

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FIG. 1. Diagram of Petri dish culture showing Lygospores (dots) between the (+) and (-) races of the same species, Mucor C and lines of "imperfect hybridization" (dashes) at contact between opposite sexes of different species, Mucor C and Mucor V.

which is taken from photograph in 7) represents a culture of the sexual races of two different species Mucor V and Mucor C. Where the two sexes of Mucor C meet a line of zygospores is evident as might be expected. The sexual race of Mucor V on the right shows a reaction only with Mucor C minus as indicated by the white line where the two meet and must be considered the opposite sex from Mucor C minus, or plus. In like manner the other sex of Mucor V on the left shows a reaction only with the plus race of Mucor C and must therefore be con

Mucor IV.

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