Recent Advances in Zoology D. P. Costello University of North Carolina, Chapel Hill, N. C Biophysical Studies HE influence of physicochemical studies of monolayers has recently extended into the zoological field. Application of the work of Langmuir and Waugh (40) on the Devaux effect (wrinkling of a monolayer of protein covering an oilwater interface, which indicates zero interfacial tension) has been made by Kopac (36, 37) to the study of the protein constituents of living and cytolyzed protoplasm of marine egg cells. He concludes that proteins do not accumulate on experimentally introduced oil interfaces while the protoplasm is intact, and that the protoplasmic proteins are essentially unstable complexes of very high molecular weight. Kopac (88) devised a method, based upon the Devaux effect, for the microestimation of protein adsorption at oil-protoplasm interfaces. Kopac and Chambers (39) studied the conditions necessary for coalescence of oil drops with various marine egg cells. They conclude that there is a critical diameter of the oil drop, below which the cell does not coalesce with the oil, and also that conditions favoring mechanical destruction or chemical dispersion of the vitelline membranes favor coalescence. From measurements of the electric impedance of suspensions of fertilized and unfertilized sea-urchin eggs, Cole (14) concludes that the increase in capacity, upon fertilization, is due entirely to a change in the plasma membrane. Cole and Curtis (15, 16) showed further that there is a decrease in the alternating-current impedance of the giant nerve fiber of the squid during the passage of a nerve impulse. Analysis of the change indicates that it is due to a decrease in the membrane resistance without an appreciable change in the membrane capacity.
T
Bioluminescence Harvey and Korr (28) find that the luminescence of the ctenophore Mnemiopsis occurs in the complete absence of dissolved oxygen, a condition such as obtains in the presence of platinized asbestos and hydrogen. In bright light, with or without oxygen, luminescence is terminated by the disappearance of the photogenic material. Luminescence returns in the dark in the presence of oxygen, but not in its absence. The authors suggest that oxygen is rather securely bound to the photogenic granules. Johnson (88) and Johnson and Anderson (84) have studied the interrelation of luminescence and respiration to the decomposition of hexoses by luminous bacteria. Glucose oxidation is inhibited by a-methyl glueoside, and the luminescence, which is increased by the addition of glucose, is likewise inhibited r relatively high concentrations of ucoside. Enzymes, Proteins, and Other Constituents of Organisms Bodine, Allen, and Boell ($) made a detailed quantitative study of the formation, activity, and substrate relations of the enzyme tyrosinase, which occurs
§
naturally in the developing egg of the grasshopper Melanoplua differentiates. At 25° C. enzyme concentration reaches a maximum at 20 days and remains thus throughout development. Bodine and Allen (7) studied the response of tyrosinase to the activators, sodium oleate, temperature, ethylurethane, urea, and acetone. Critical points were demonstrated for all activators; for some, the simultaneous activation of, and injury to, the enzyme. Holter and Doyle (29), upon investigating the enzymes amylase, catalase, and peptidase in the protozoa Amoeba proteus, Paramoecium caudatum, and FronUmia sp., found it possible to distinguish characteristic enzymatic activity ranges of the three species. Hecht and Pickels (28) determined the sedimentation constant of visual purple, the photosensitive substance of the rods of the vertebrate eye, and suggest that the molecular weight of this substance (which is probably a protein) is about 270,000. They conclude that the shape of the visual purple molecule is slightly oval. From the fact that the electrical response in dark-adapted frogs' eyes may be greatly reduced without a parallel diminution of the visual purple pigment, Granit, Holmberg, and Zewi (25) conclude that the retinal rods contain a store of visual purple, only the surface of which appears to be active at a given time. From the rate of sedimentation (in an ultracentrifuge) of the serum proteins of various vertebrate animals, Svedberg and Andersson (49) infer that the serum proteins of mammals, reptiles, birds, amphibians, and fishes are very much alike, as regards molecular weight, but differ from those present in the serum of lampreys. According to Fox and Moe (20), the small red-orange anemone Epiactis prolifera, which inhabits the ocean waters of the Pacific coast, owes its color to a red, acidic carotenoia, similar to astacene (a tetraketo-0-carotene), which is present in esterified form. Marks (48) determined the copper content and copper tolerance of several species of mollusks of the southern California coast. The upper limit of copper tolerance for most of these species is in the range from 0.10 to 0.20 mg. of added copper per kg. of sea water. Gallup and Norris (fsiu i*om experiments upon chicks fed on a low manganese diet, conclude that manganese in small amounts is essential for normal bone de17
velopment and prevents certain bone deformities, such as perosis. R. R. Bensley (2) extracted plasmosin from hepatic cells and studied some of its properties. He considers plasmosin to be the gel- and fiber-forming constituent of the protoplasm of the hepatic cell. The solubilities of the secretion granules of the guinea pig pancreas have been tested by three methods by S. H. Bensley (8). The solubilities of the alpha granules differ from those of the beta and zymogen granules, except in sodium hydroxide and ethylene glycol. S. H. Bensley and C. A. Woerner (4) conclude that in the guinea pig the secretion of the alpha cells of the islands of Langerhans is concerned with fiat metabolism; the complete oxidation of fat depends upon an adequate supply of oxidizable sugar in addition to the secretion of the alpha cells. Slifer (47) finds at the posterior end of the grasshopper egg a small circular area, the hydropyle, which, in contrast with the remaining cuticle, becomes excessively thin and transparent on treatment with potassium hydroxide. A number of large cells in this area, different from those elsewhere, are believed to constitute a secretory organ by means of which water is taken into the egg. Ultraviolet Radiation Chase (12) obtained delayed cleavage of the eggs of the starfish Dendrasier and of the echiuroid worm Urechis, produced by the full spectrum of an ultraviolet mercury arc. Giese (22,28) studied the effects of a series of dosages of known intensities of monochromatic quartz ultraviolet light on the eggs of the sea urchin Strongylocentrotu8 purpuratus. The highest dosages of X3,660 A. produced little or no effect on cleavage rate; X2804 A. produced the greatest retardation. No marked acceleration was observed. Giese suggests that the destructive effect may be mediated by some substence in the egg sensitive to X2,804 A. Giese (24) irradiated members of eleven species of protozoa with ultraviolet light (X2.537 A.) and found that each showed a characteristic resistance to the radiation. This resistance was dependent upon (a) the absorption of light by the protoplasm, (b) the nature of the protoplasm, closely related species showing comparable resistance, (c) the pigments present, (d) the physiological state of the organisms, and (e) the environmental conditions, to some extent.
18
INDUSTRIAL AND ENGINEERING CHEMISTRY
Experimental Embryology In the field of chemical embryology Hayes {27) made estimations of the total fat, sterol, and phospholipide during the first 40 hours of development of the egg of the sea urchin Arbacia. The total fat decreases during the first 8 hours, increases for about 10 hours, then decreases again. The sterol concentration remains unchanged. The results are interpreted in terms of apparent sources of energy for embryonic development. By using a Cartesian diver method for detecting minute pressure variations, so that a change of 0.000001 cc. of gas can be observed, Needham, Boell, and Rogers (46) are investigating anaerobic glycolysis in different parts of the developing amphibian embryo (gastrula). Tyler and Horowitz (60) present data on the concentrations of fifteen different nitro- and halophenols giving rise to optimum respiratory stimulation and to reversible cleavage block in fertilized sea-urchin eggs. The data indicate that the penetration is accomplished in the undissociated form and that the anion is the active agent. The inquiry into the chemical nature of the amphibian organizer has been continued by Barth (/). Experiments showed that cephalin preparations, which induced neural tube formation, were toxic and caused cytolysis. Certain other cytolytic agents had similar inducing action. It is suggested that some inductive agents stimulate the production of neural tubes by partial cytolysis of cells, whereas a substance resent in the protein residue of calves' rains and frog gastrulae may correspond to the naturally occurring organizer. Bodenstein (6), as a result of constriction and transplantation experiments upon larvae of Drosopkila, concludes that there is a factor at the anterior end of the larva, upon which pupal metamorphosis is dependent. This factor acts about 12 hours before pupation. If the anterior part of the larva is separated from the posterior part by a ligature made after this period, both parts pupate. If the ligature is made earlier, only the anterior portion pupates. Somewhat similar results (6) were obtained with a moth, Phryganida oalifornica, in which the development of the abdominal ectoderm of the imago is dependent upon a factor in the anterior part of the pupa. Ephrussi, Khouvine, and Chevais (19) find that Calliphora extracts considerably increase the number of facets in the eye of the Bar mutant of Droeovhila melanogaster. They believe that the extract contains a morphogenetic (facet-forming) substance under genetic control. Holtfreter (SO) records an alteration of the induction capacity of pieces of early Triton gastrula ectoderm if aged before implantation into neurulae of Triton or Bombinator. By culturing pieces of early chick primitive-streak blastoderms, Rudnick Q6) concludes that the presence of entoderm has no effect on the differentiation of upper layers, that ectodermal pieces may form medullary tubes in vitro, and that notochord and axial mesodermal structures depend upon the definitive organization of the primitive streak and node. Hdrstadius (SI) constricted eggs of the echinoderm Psammechinus miliaris, in the 2- to 64-cell stages, with single silk fibers. The results are in harmony with earlier experiments upon isolated blastomeres and stretched eggs, in regard to dependent differentiation along the egg axis. Clement (IS) studied the development of centrifuged eras and egg fragments of the snail Physaheterostropha. Nucleated fragments containing only hyaline protoplasm and mitochondria developed into structurally complete snails of adult form.
E
In eggs centrifuged in the 2- and 4-cell stages a subsequent displacement of certain organs was observed. Results in the field of botanical embryology, 'which may be of profound importance for the study of development in general, have been obtained by Whitaker (61, 62), using the eggs of the alga Fucue. Fertilized eggs, centrifuged at 150,000 times gravity at pH 7.9-8.1, formed rhizoids at the centrifugal ends; atpH5.£6.1 rhizoids formed at the centripetal ends. Whitaker suggests that the effects may be due to concentration and toxic overconcentration, respectively, of growth hormone by centrifuging. Lillie and Juhn (41) made a major contribution to the general principles of development by their studies of the physiology of development of the afterfeather of fowl. Wilier and Rawles (68, 64, 66) showed that minute pieces of head skin ectoderm from chick embryos of the breeds Barred Plymouth Bock, Rhode Island Bed, and Fi hybrid, grafted to the base of the wing bud of an embryo of the White Leghorn breed,resultsin the formation of an extensive area of pigmented down feathers covering the entire wing and, often, adjacent parts of the body. In reciprocal experiments, skin ectoderm from White Leghorn grafted to pigmented hosts failed to produce patches of white feathers. They conclude that the feather of the graft area is the result of the joint action of the host feather germs and of some influence (chromatophores or diffusible substances) originating from the implant. The feather structure is the product of the host feather germs, but its color pattern is produced under the control of the implanted cells. Nuclei, Chromosomes, and Sex Types Differences from the normal values in the nucleic acid content of the salivary gland chromosomes in races of Drosophila melanoaaster exhibiting variegation have been demonstrated by Caspersson and Schultz (11) by optical methods. Taken together with other data on viruses and chromosomes, their results suggest the possibility that nucleic acid synthesis is characteristic of "self-reproducing molecules." Caspersson ana Hammersten (10) deduce that the molecules of sodium thymonucleate, a constituent of chromosomes, have in solution the form of thin rods and a molecular weight between 500,000 and 1,000,000. The large salivary gland cells of dipteran larvae, employed extensively for cytogenetic studies, have been used by Buck and Boche (9) for studies of the osmotic properties of living chromosomes. In the normal living condition the chromosomes so nearly fill the nucleus that nuclear volume equals chromosomal volume, and volume changes occur when hypo- and hypertonic Ringer solutions are injected into the larva. Melland (44) found that the nuclei of living salivary gland cells, dissected out after the glands were subjected to 0.25 per cent egg albumen solution for 2-3 hours at 5 ° C , react osmotically to various salt solutions.
VOL. 17, NO. 1
Duryee (17) isolated germinal vesicles (oocyte nuclei) of the frog and concludes that the nucleus is an elastic colloidal gel. with a negative charge on the dispersed phases, ana the matrix well on the alkaline side with an isoelectric point between pH 4.0 and 4.8. Exceptionally large synaptic chromosomes (over 600 microns long in the relaxed condition) from the germinal vesicles of ovarian salamander eggs were used for microdissection studies by Duryee (18). Changes in these chromosomes during the growth period were observed. The relative tensile strength of chromonemata (single chromosomal strands) was measured in Ringer solutions, with and without calcium. McClung (42) suggested that the sequence of gene action during ontogeny may recapitulate the phylogenetic histories of the chromosomes. According to this theory, which provides a new point of departure for cytogenetic studies, the older, more proximal, "genetically inert" portions of chromosomes may be concerned with the earlier ontogeny during which the more general characteristics are laid down, while the newer, more distal portions of the chromosomes bear genes concerned with the less general, more recently evolved characteristics. Jennings (S2) has supplemented the work of Sonneborn (48) and Kimball (35) on sex in the protozoon Paramoecium aurelia with studies of sex reaction types of Paramoecium bursaria. In this latter species nine reaction types have been discovered, whereas there are only two in Paramoecium aurelia. Literature Cited (1) Barth, L. G., Anat. Record, 70 (Suppl. 1), 101 (1937). (2) Bensiey, R. R., Ibid., 72,351 (1938). (3) Bensiey. S. H., Ibid., 72, 131 (1938). (4) Bensiey, S. H., and Woeroer, C. A., Ibid., 72. 413-28 (1938). (5) Bodenstein, D., Arch. Entvricklungsmeeh. Organ., 137, 474 (1938). (6) Ibid., 137. 636 (1938). (7) Bodine, J. H., and Allen. T. H.. J. Cellular Comp. Physiol., 12,71 (1938). (8) Bodine, J. H., Allen, T. H.v and Boell, E. J., Anat. Record, 70 (Suppl. 1), 80 (1937). (9) Buck, J. B., and Boche, R.'D., Biol. Bull.. 75. 344 (1938). (10) Caspersson, T., and Hammersten, £., Nature, 141, 123 (1938). (11) Caspersson, T.f and Schultz, J., Ibid., 142, 294 (1938). (12) Chase, H. Y., Biol. Bull., 75,134 (1938). (13) Clement, A. C , J. ExpU. ZooL, 79, 435 (1938). (14) Cole, K. C , Nature, 141, 79 (1938). (15) Cole, K. C, and Curtis, H. J., Biol. Bull., 75, 358 (1938). (16) Cole, K. C , and Curtis, H. J., Nature, 142, 209 (1938). (17) Duryee, W. R., Anat. Record, 70 (Suppl. 1), 71 (1937). (18) Duryee, W. R.. Biol. Bull., 75, 345 (1938). (19) Ephrussi, B., Khouvine, Y., and Chevais, S., Nature, 141, 204 (1938). (20) Fox, D. L., and Moe, C. R., Proc. Natl. Acad. Set. U. S., 24, 230 (1938). (21) Gallup, W. D., and Norris, L. C . Science, 87, 18 (1938). (22) Giese, A. C , Biol. Bull., 74, 330 (1938). (23) Ibid., 75, 238 (1938). (24) Giese, A. C , J. Cellular Comp. Physiol., 12, 129 (1938). (25) Granit, R., Holmberg, T., and Zewi, M., Nature, 142, 397 (1938). (26) Harvey, E. N., and Korr, I. M., J. Cellular Comp. Physiol., 12. 319 (1938). (27) Hayes, F. R.. Biol. BuU., 74, 267 (1938). (Continued on page 22)
INDUSTRIAL AND ENGINEERING CHEMISTRY
22
(36) Kopac, M. J., AnaL Record, 70 (Suppl. 1), 71 (1937). (37) Kopac, M. J., Biol. Bull., 75,351 (1938). {Continued from page J5) (38) Ibid., 75, 372 (1938). (28) Hecht, S., and Pickels, E. G., Proc. (39) Kopac, M. J., and Chambers, R.( Ibid., 75. 372 (1938). Natl. Acad. Sci. U. S., 24.172 (1938). (29) Holter, H.( and Doyle, W. L., J. Cellu- (40) Langmuir, I., and Waugh, D. F., J. Gen. Physiol., 21, 745 (1938). lar Comp. Physiol., 12, 295 (1938). (30) Holtfreter, J., Arch. Entwicktungsmech. (41) Lillie, F. R., and Juhn, M.. Physiol. Zool., 11, 434 (1938). Organ., 138, 163 (1938). (42) McClung, C. £., Proc. Natl. Acad. Sci. (31) H6rstadius..S.f I&u*., 138,197(1938). U. S., 24, 439 (1938). (32) Jennings, H. S.f Proc Nad. Acad. Sri. (43) Marks, G. W.t Biol. Bull., 75, 224 U. S., 24, 117 (1938). (1938). (33) Johnson, F. H., J. Cellular Comp. (44) Melland, A. M.. Ibid., 75. 348 (1938). Physiol.. 12, 281 (1938). (45) Needham, J., Boell, E. J., and Rogers, (34) Johnson, F. H., and Anderson, R. S., V., Nature, 141, 973 (1938). Ibid.. 12, 273 (1938). (35) Kimball, R. F., Proc. Nail. Acad. Sri. (46) Rudnick, D., J. ExpU. Zool., 79, 399 (1938). U. S., 23, 469 (1937).
Zoology
Physics Karl K. Darrow, 230 West 105th S t . , New York, N. Y. EDITOR'S NOTE:
We
are
deeply
in-
debted to Mr. Darrow for the following paragraphs on physics which he kindly prepared for us, almost at a moment 8 notice, when the review for 1938 on this subject which we had been counting upon failed to materialize. HESE paragraphs are in no sense a review of the progress of physics during T 1938; they consist merely of allusions to
a few advances in subatomic or nuclear physics which of late have merited the attention of physicists and possibly that of chemists also. The particle variously named "heavy electron/' "barytron," "Yukawa particle," and (preferably) "mesotron" is steadily winning its way to acceptance. A constituent of the cosmic rays, it has not as yet been produced by any artifice of the laboratory, and whatever is known or conjectured about it is a portion of the science of cosmic rays. The enormous energies with which cosmic-ray particles are endowed—energies ranging upward to the billions of electron volts—transcend by several orders of magnitude the greatest energies which can be imparted to recognized electrons or protons in the laboratory. This means that we cannot compare a cosmic-ray particle with a known electron of equal energy and thereby settle the question of identity vs. difference. The question poses itself in the form: Do cosmic-ray particles behave as theory predicts that electrons of such great energy should behave, or do they not? When the question is posed in this form, it is seen to be an interesting one per se; but one may feel that it renders meaningless the original question "is there a heavy electron?" For, suppose that the cosmicray particles were found to depart from the predictions of theory: This might be taken as meaning that they are particles of a different nature from electrons, but it might also be taken as meaning that they are true electrons and that the theory is wrong. The answer to the question does not, however, suffer from this ambiguity; for it is found that there are two categories of particles, one of them behaving (roughly, at least) in concordance with the theory, the other departing from it definitely. The category of particles classified as true electrons is distinguished by the feature that they produce "cosmic-ray showers." These, the most striking and beautiful of all the cosmic-ray phenomena, are composed of quantities of electrons and of photons of great energy, bursting out of
pieces of dense matter. The initiating electron of colossal energy is believed to radiate its energy in the form of photons; as it cleaves through the dense matter, these photons convert themselves into pairs of electrons of opposite sign, themselves endowed with large kinetic energies; the electrons lose their kinetic energies in the same manner, and photons are created along their courses and also where positive electrons merge with negatives; the processes alternate, and showers are built up in cumulative fashion. These are processes which are attributed by theory to electrons, and accordingly the showerproducing particles and the charged particles of the showers are identified with electrons. The category of particles classified as mesotrons is distinguished by the negative feature that they do not produce showers, and by the positive feature that they penetrate many centimeters, even a meter or more, of materials as dense as lead; theory says definitely that no electron of even the cosmic-ray energies could get through as much as 10 centimeters of lead. They may also be distinguished from electrons by the ionization along their paths through air or other gases in the expansion chamber of Wilson. For making the distinction, a strong magnetic field must be applied to the chamber, curving the tracks of the particles which fly through. In a field of known strength the ionization density appropriate to electrons is a known function of the curvature of the track. Should one find a track of which the ionization density was definitely several times too high to agree with this function, one would identify it as the track of a mesotron (unless there should be reason to fear that the curvature had been distorted, a possibility which must be carefully examined). A dozen or so such tracks have been reported. If they have been correctly interpreted, the mass of the mesotron is a couple of hundred times as great as that of the electron, its charge the same in magnitude, and either positive or negative in sign. The names to be mentioned in the history of the mesotron are those of C. D. Anderson and S. Neddermeyer, in the first line; then, those of Street, Stevenson, Blackett, Auger, Ehrenfest, and several others. An ingenious method for determining the magnetic moments of nuclei has been invented in the past few months by Rabi, and applied already to half-a-dozen nuclear types. The molecules containing the nuclei (the electron systems of these molecules are so constituted that their magnetic
VOL. 17, NO. 1
(47) Slifer, E. H., Quart. J. Micro. Sci., SO, 437 (1938). (48) Sonneborn, T. M., Proc. Natl. Acad. Sou, 23, 378 (1937). (49) Svedberg, T., and Andersson. EL, Nature, 142, 147 (1938). (50) Tyler, A., and Horowits, N. H., BioL Bull., 75, 209 (1938). (51) Whitaker, D. M., Anat. Record, 70 (Suppl. 1), 70 (1937). (52) Whitaker, D. M., Proc. Natl. Acad. Sci. U. S., 24. 85 (1938). (53) Willier, B. H., and Rawlea, M. E., Anat. Record, 70 (Suppl. 3), 81 (1938). (54) Willier, B. H., and Rawlea, M. E., Bid. Bull., 75, 340 (1938). (55) Willier, B. H., and Rawlea, M. E., Proc. Natl. Acad. Sci. U. 8., 24. 446 (1938).
moments vanish) pass through an inhomogeneous magnetic field. The nuclei distribute themselves among their two (or more) permitted orientations in this field, and those which share a particular orientation are deflected by the field along a certain path. Midway in this path is interposed a small region over which an oscillating magnetic field is applied to the flying molecules. There is a critical frequency of oscillation, for which this field is able to impel the nuclei to change over into another of their permitted orientations. When this happens to any nucleus the deflecting force upon the molecule is changed, the molecule no longer continues along its original path, and a measuring device placed in the prolongation of the original path reports a minimum in the strength of the arriving beam. The critical frequency depends upon the magnetic moment of the nucleus, which accordingly is computed from the data. Values are now available for the magnetic moments of the nuclei of hydrogen, deuterium, sodium, cesium, and the isotope 39 of potassium. While the numerous great cyclotrons lately completed or in process of building attract most attention, the electrostatic generator is also proving its merits for the production of high-energy protons, deuterons, and alpha-particles for use in transmutation. The earliest generators stood in large halls or in the open air, but the newer ones are smaller in scale and are enclosed in tanks containing air mixed with freon and raised to a pressure of several atmospheres. Herb and his colleagues, to take one example, have worked at voltages up to 2,500,000 with proton streams forming currents of the order of a milliampere. With this they have explored the fields in the immediate vicinity of protons, by projecting them against other protons and making a statistical study of their deflections. They have also studied the excitation of gamma-rays—i. e., of highfrequency light, occurring when protons are projected against fluorine nuclei: the curves of radiated energy vs. energy of incident protons consist ofpeaks wonderfully sharp and narrow, speaking strongly for the controllability of the apparatus itself as well as for the sharpness of these "resonances" at which the radiation process occurs. To analyze the emitted radiation is a task of another sort, requiring that the rays be sent through expansion chambers: in these are seen the tracks of electrons ejected from the atoms by the photons, and also the tracks of electron pairs created by the photons. The spectrum of the gamma-rays must be deduced from the energy distribution of these electrons and these electron pairs, a difficult operation which has been carried out chiefly in California by Lauritsen, Crane, Fowler, J. R. Richardson, and others.
