Page:Encyclopædia Britannica, Ninth Edition, v. 14.djvu/418

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colonel for his conduct at the siege of Chapultepec, where he was wounded. In 1852 he was appointed superintendent of the academy at West Point, and in 1855 he was promoted lieutenant-colonel of the second regiment of cavalry, with which he served in Texas. In March 1861 he was made colonel of the first regiment of cavalry, but in the following month, learning that his native State had withdrawn from the Union, he resigned as an officer of the United States army, and was forthwith put in command of the Virginian forces. When Virginia joined the Confederacy he was the third of five generals appointed by the Southern Congress. No adequate opportunity of gaining distinction was afforded him, however, until the beginning of June 1862, when he received command of the army of northern Virginia, and commenced the series of operations the result of which before the month had closed was to compel M'Clellan to abandon the siege of Richmond. Following up this advantage and Jackson's victory at Cedar Run on August 9, Lee advanced in person to lead the army that was being formed on the south bank of the Rapidan; after crossing that river he indicted upon Pope at Manassas the disastrous defeat by which the Federal army was compelled to retire within the fortified lines of Washington. Lee now decided on the invasion of Maryland, and advanced to Frederick city, but, being compelled to divide his forces, he sustained a check in the passes of South Mountain (September 16, 17) which compelled him to recross the Potomac. After a few weeks' breathing time he found himself again face to face with the Federal army near Fredericksburg early in November; on December 13 the enemy, having crossed the Rappahannock on the previous day, assailed his position in strength, but was defeated with great loss. In the following spring the hostile armies still faced one another on the Rappahannock, but the brilliant strategy of Lee, as exhibited in the battles at Chancellorsville (May 2-4), against vastly superior forces, resulted in the retreat of the enemy, while Lee was left free to resume his old policy of throwing the Federal forces on the defensive by an advance into Pennsylvania. He encountered the enemy near Gettysburg on July 1, and decided advantages were gained, but the struggle was renewed on the two following days with disastrous consequences to him; he retreated, however, in good order, and reached Virginia on the 12th, when the campaign of the year practically closed. That of 1864 began on May 4, when Grant crossed the Rapidan; the passage itself was unresisted, but his subsequent progress was hotly contested in a series of well-fought battles which did not prevent the Federal general from reaching the south side of the Appomattox. The siege of Petersburg began in June, and lasted until April 2, 1865. A week afterwards Lee surrendered with his whole army, thus virtually terminating the war. In the same year he was elected president of Washington and Lee university at Lexington, Virginia, which office he retained until his death on October 12, 1870.

The events of Lee's military career briefly indicated in this notice belong to the history of the United States, and will call for further notice in that connexion. To do justice to his extraordinary ability as a general, displayed under circumstances of extreme difficulty, when his movements were continually hampered by political necessities, as well by the lack of material resources, would require an elaborate military biography; it was never more nobly displayed than in the last hopeless stages of the fatal struggle. The personal history of Lee is lost in the history of the great crisis of America's national life; political friends and foes alike acknowledged the disinterestedness and purity of his motives, his self-denying sense of duty, and the unrepining loyalty with which he accepted the ruin of his party.

Fig. 1 – Medicinal Leech (Hirudo medicinalis, L.), after Moquin-Tandon and Rolleston. a, anterior sucker; a', posterior sucker; b, first and second pairs of ganglia – closely approximated; b', last ganglion; c, first diverticulum of the alimentary canal; c', small intestine (gastroiléal of Gratiolet); c", eleventh pair of cæca (long and large); d, first pair of the nine testes; d', last pair of testes; d", sixth testis displaced outward so as to show its connexion with the vas deferens; e, e', segmental organs; f, muscular ductus ejaculatorius of the left side, leading from the vesicula seminalis to the base of the flask-shaped intromittent organ; g, club-shaped end of the intromittent apparatus; h, penis; i, ovary of the left side; j, muscular vagina.

LEECH. The medicinal leech (Hirudo medicinalis, L.) is a species grouped under the family Gnathobdellidæ (with a dental apparatus composed of armed muscular ridges) of the discophorous Annelida. The body of a leech is spindle- shaped, and flattened dorsally and ventrally so as to be elliptical in transverse section. It is somewhat pointed in front except when the mouth is in action, while posteriorly it is terminated by a disk or sucker. The surface is marked by a series of annulations reaching from ninety-five to one hundred, but such are only cutaneous, as indicated by the ganglia, the segmental organs, the white spots on each side, and even by the arrangement of the two outer yellowish stripes, for the primary segments of the body comprise from three to five of these. The anterior sucker (fig. 1, a) is composed of four incomplete annuli and an other surrounding the mouth, while the posterior (a') has seven. The colour of the dorsum is gene rally dull olive or olive-brown, with six yellowish, rusty, or greenish-yellow bands more or less interrupted with black, the spots of the latter being some what symmetrically arranged in the two outer rows. The ventral surface is speckled with black spots on a greyish ground. Seve- ral varieties occur, according as the dorsum is lighter or darker brownish or olive, and the vent- ral surface with or without spots. Thus Moquin-Tandon, Diesing, and others indicate six or seven, each of which again has various subvarieties, ranging from two to five. Externally the body is invested by a thin translucent chitinous cuticle, which is per forated, apparently with some regularity, by the apertures of the glands. This coat is shed at intervals. Beneath is the hypoderm (epidermis of some), which is much firmer and thinner than in the Nemerteans. It contains the pigment, though part of the latter intrudes into the subjacent layer, and is com- posed as usual of columnar granular cells, a horizontal sec- tion presenting a somewhat regularly areolated aspect. Raw- lins Johnson alludes to the vas- cularity of the surface of the leech, and Ray Lankester notes the extension of the capillaries into this layer. The latter has not been verified, even in the hypoderm of the snout, though preparations presenting such appear- ances are not uncommon. The hypoderm is closely united to the subjacent muscular layer, though it can hardly be said with Gegenbaur that it is continued into the parenchyma of the body. It is this layer and the cuticle which are marked by the superficial annulations. Various unicellular glands occur underneath the hypoderm, in particular two chief sets – superficial and deep. The former are situated amongst the outer (circular) muscular fibres and pigment, while the latter lie amongst the con- nective tissue, muscular fibres, and vessels that constitute