MOORE, C. U.-Nutrition of Mother | INDUSTRIAL CHEMISTRY AND and Child. Lippincott. PHILIP, J. C.-Physical Chemistry; ROCKWOOD, E. W., and ROCKWOOD, STILES, P. G.-Nutritional Physiol- WELLS, H. G.-The Chemical Aspects of Immunity. Chem. Cat. Co. CHEMICAL ENGINEERING AITCHISON, L., and BARCLAY, W. R.- ALLEN, R.-Bismuth Ores. Murray. Van Nostrand. ANDES, L. E., and STOCKS, H. B.- BADGER, W. L.-Heat Transfer and Leather. Van Nostrand. BOYD, T. A.-Gasoline-What Every- BURRELL, G. A.-The Recovery of CARPENTER, L.-Mechanical Mixing NAMARI, I.-The Electrolytic Separation of Magnesium from Magnesia. COFFIGNIER, C.-Colors and Var nishes. Scott, Greenwood. Namari. RIMBOLD, W. G.-Bauxite and Alu-DANIELS, G. W.-Refrigeration in the minium. Murray. THOMPSON, M. DE K.-Theoretical and Rev. THOM, C., and HUNTER, A. C.-Hy- AGRICULTURAL CHEMISTRY Chemical Industry. Rayment. DULY, S. J.-Timber and Timber FARNHAM, D. T., et al.-Profitable Science in Industry. Macmillan. FIELD, S., and BONNEY, S. R.--Chem ical Coloring of Metals. Chapman. FISCHER, F., and LESSING, R.-The Conversion of Coal into Oils. Benn. DOWLING, R. N.-Sugar Beet from GARDNER, H. A.-Physical and Chem Field to Factory. Benn. Van Nostrand. ical Examination of Paints, Var nishes and Colors. 2d ed., Inst. Paint and Var. Res. GIBBS, W. E.-The Dust Hazard in 2d ed., Griffin. GILLETT, H. W., and MACK, E. L.-| SEARLE, A. B.-Refractory Materials. LADOO, R. B.-Non-Metallic Minerals. MACLAREN, W. A.-Rubber, Tea, MARTIN, G.-The Modern Soap and MCKEE, Ralph H., et al.-Shale Oil. MILES, F. D.-Manufacture of Sul- NORTH, S. H., and GARBE, J. B.-Low POLLITT, A. A.-The Technology of SADTLER, S. P., and MATOS, L. J.- SEYMOUR, H.-Agitating, Stirring and SIMPKIN, N.-Boiler-Feed SNOW, E. C.-Leather, Hides, Skins SPIELMANN, P. E.-Bituminous Sub- TAMANN, G., DEAN, R. S., and SWEN- Cat. Co. WEST, C. J., and BEROLZHEIMER, D. D.-Bibliography of bibliographies on Chemistry and Chemical Technology. Nat. Res. Council. PHYSICS ADLAM, G. H. C., and LATTER, O. H.- C.-Space and Time. BOND, W. N.-An Introduction to BORN, M. and BROSE, H. L.-Ein- BRAGG, W.-Concerning the Nature of CAMPBELL, L. L.-Galvanomagnetic mans. ELLIS, C., and WELLS, A. A.-Chemi- FERRY, E. S.-General Physics and Its GOUGH, H. J.-The Fatigue of Metals. HAAS, A.-Introduction to Theoreti- HARRIS, F. S., and BUTT, N. I.-Scien- LUCKIESCH, M.-Foundations of the MARTIN, L. C., and GAMBLE, W. Color and Methods of Color Repro- PANNELL, J. R.-Measurement of liam Strutt, Third Baron Raleigh. Arnold. WHETHAM, W. C. D.-Recent Devel opment of Physical Science. Blakiston. ATOMIC THEORY RINNE, F., and STILES, Walter S.-ANDRADE, E. N. da C.-The Structure of the Atom. Bell. ASTON, F. W.-Isotopes. Arnold. BOHR, N.-The Theory of Spectra and Atomic Constitution. 2d ed., Cambridge. CRANSTON, J. A.-The Structure of Matter. Chapman. DIVISION XXXII BIOLOGICAL SCIENCES ORGANIC EVOLUTION BY H. S. JENNINGS PROFESSOR AT JOHNS HOPKINS UNIVERSITY The present time sees in progress 1. Divisions.-Sometimes the chro a notable advance in the understand-mosomes divide and thus double, withing of the nature and origin of mu-out cell division. This may happen tations and "what are called spe- in the fertilized egg, so that it now cies" and through this, possibly, of contains four sets in place of two. some of the major factors in evolu- Thereafter cell divisions coincide with tion. The nature of this advance may chromosomal divisions, so that an unbe set forth as follows. dividual is produced with four sets Evolution and Chromosomal of chromosomes in its cells. Such Changes. The way in which an or- individuals are larger, with larger ganism develops and the characteris- cells and organs, and may differ in tics it produces are known to depend, structure from the parent stock, with in large measure, on the stock of sub- but two sets. They now propagate stances present in its chromosomes; themselves in the usual way, so that these, by interaction with each other a mutation or new race is produced. and with other things, produce the One of the well known mutations of developed organism. Altering any of Oenothera is of this nature, and these substances alters the character-races with four sets of chromosomes istics produced. Any such alteration are known for several organisms. that is handed on to new generations 2. Three Sets.-These individuals results in new inherited character- with four sets produce germ cells istics, in a "mutation," a new "ele- with two sets; such a germ cell may mentary species." Evolutionary unite with one containing but a sinchange lies essentially in the perma-gle set, thus producing an individual nent alteration of the chromosomal with three sets. These differ both substances. Certain methods by which these substances are altered are coming to light. An individual at the beginning is formed by the union of two germ cells, and each of the two germ cells contains a single "set" of chromosomes-of definite constitution and number. The individual so produced thus contains two such sets; its chromosomes are in pairs. In development all the chromosomes divide at each cell division, so that all the cells of the typical individual contain the two sets. Alternations of the chromosomal outfit are found to occur as follows: from those with two sets and those with four sets. The odd number of sets of chromosomes causes disturbances in the usual method of reproduction by union of two germ cells, but, such individuals with three sets at times reproduce from a single germ cell, yielding thus a permanently diverse race. 3. Classes.-Irregularities in germ cells in races with three sets of chromosomes give rise to numerous different classes of germ cells, with diverse combinations of chromosomes. Some of these on union with other germ cells can develop; they thus give rise to hereditarily diverse races. CHEMICAL ENGINEERING AITCHISON, L., and BARCLAY, W. R. MOORE, C. U.-Nutrition of Mother | INDUSTRIAL CHEMISTRY AND PHILIP, J. C.-Physical Chemistry; ROCKWOOD, E. W., and ROCKWOOD, STILES, P. G.-Nutritional Physiol- ELECTRO-CHEMISTRY Food. Lewis. NAMARI, I.-The Electrolytic Separa- RUMBOLD, W. G.-Bauxite and Alu- Rev. THOM, C., and HUNTER, A. C.-Hygienic Fundamentals of Food Handling. Williams & Wilkins. VALLERY-RADOT, R., and DEVONSHIRE, R. L.-The Life of Pasteur. Doubleday, Page. WILLIAMS, G. B.-Sewage Disposal in India and the East. Thacker. AGRICULTURAL CHEMISTRY Engineering Non-Ferrous Metals tions. Chem. Cat. Co. ANDERSON, R. J.-Metallurgy of Alu- minium and Aluminium Alloys. Leather. Van Nostrand. BOYD, T. A.-Gasoline-What Every BURRELL, G. A.-The Recovery of CARPENTER, L.-Mechanical Mixing C.-Colors and Var DULY, S. J.-Timber and Timber FARNHAM, D. T., et al.-Profitable Science in Industry. Macmillan. FIELD, S., and BONNEY, S. R.--Chem ical Coloring of Metals. Chapman. GIBBS, W. E.-The Dust Hazard in |