Page:The New International Encyclopædia 1st ed. v. 18.djvu/511

* SPERMACETI. 439 SPERMATOPHYTES. macrocephalus), which lives in the Pacific and Indian Oceans. In the living whale it is dissolved in an oil, but on cooling separates as a solid. As much as twelve barrels of crude spermaceti is obtained from an ordinary whale. It is purified by pressure, melting, and crystallization. It is white or translucent, crystallizable from alcohol and ether, not soluble in water, smooth to the touch, and without taste or odor. It becomes rancid and grows yellowish on exposure to light. It burns with a bright flame. Its specific gravity is .945, and its melting-point is about 38° C. (about 100° F.). It does not, like fats and oils, give glycerin after saponification, but cetyl alcohol. It consists chiefly of cetin, or cetyl pal- mitate, ^'« w'" 2 ]-0. Spermaceti is used as an ingredient of many ointments and cerates. It is made into sperm candles of definite weight for photometric purposes. SPERMATISTS. A school of physiologists of the seventeenth century, who held that the whole of the material transmitted from the parents to the offspring as the foundation of the embryo was contained in the spermatozoon of the male, opposing those (the oviilists) who asserted that all the material was supplied by the mother in the egg. 8cc Preformation. SPERMATOPHYTES (from Gk. ffwipfin, sperma, seed + tpurdu, pin/ton, plant), Seed- Plants. The highest of the four primary divi- sions of the plant kingdom, distinguished from the other groups by the production of seeds. The much used name phanerogams, meaning evident sexual reproduction, is unfortunate because in this group sexual reproduction is least evident. The once used name anthophytes, meaning flow- ering plants, which last is probably the most com- monly used popular name, is also inappropriate, since the production of flowers is not coextensive with the group. The most recently proposed name siphonogams, meaning sexual reproduction by means of a tube, referring to the passage of the male cells to the eggs through pollen-tubes, has not been extensively adopted. Since the seed-production seems to distinguish the group more than any other character, the name sperma- tophytes, which is in common use, seems likely to prevail. This group, which includes practically all the conspicuous vegetation (herbs, shrubs, and trees) , is by far the most useful group to man, so useful, indeed, that luitil the closing years of the nine- teenth century elementary botanical training dealt with no other group and botanists were thought of chiefly as students of flowers. More than 100,- 000 species of seed-plants have been described, and grouped in two distinct but very unequal divisions— gymnosperms (q.v.) and angiosperms (q.v.). They are distinguished by the position of their seeds, which are naked or freel.y exposed in the former, but inclosed in a seed-case in the latter. In all seed-plants the alternation of generations (q.v.) is very much obscured by the great reduc- tion of the sexual plants, which are not popularly recognized, and are undiscoverable except by laboratory manipulation, the whole visible ho(ty of these plants, contrary to the popular notion, being the sexless phase or sporophyte. All the members of the group are also heterosporous. (See Hetercspory. ) The pollen-grain is a sex- less microspore that in germination gives rise to a small plant consisting of only a few cells, among them two male cells, which are formed within the pollen-grain and are to function as sperms. The pollen-grain is transferred to the immediate neighborhood of the female plant, usually by the wind or by insects. See Polli- nation; Fertilization. The niegaspore, a large sexless spore, that pro- duces the female plant, is developed within the Fig. 1. OVULE. Showing i, Integnun-iit; e. euibryo-sac; a, antipodal cells; p, polar nuclei f»ising; s, syneryids; o, eggs; and w, pollen tube containing male cells. ovule, which is, therefore, a sporangium. The fact that in this sporangium there is but a single mega- spore, and that is not discharged, but retained, Fig. 2. ovttle in ovahy cavity. Showing (', integument ; it, nucellus ; 5, embryo-sac ; and c, embryo. is what makes a seed possible ; for the retained megaspore germinates within its sporangium