724 BLISTER BLOCKADE which formerly included all the sealed reptiles with very short or no feet, and with the scales nearly alike ahove and helow. It is gentle and inoffensive in its habits, and quite harmless ; even if provoked to bite, its teeth are so small and weak as hardly to make an impression upon the human skin. It is very timid, and when taken hold of is in the habit of forcibly and stiffly contracting the body, in which state it becomes so fragile as to be broken by a slight blow, or an attempt to bend it ; hence its specific name fray His. The glass snake, an American species of saurian (ophuaurw), pos- sesses the same property, as do many other scincoids. There is no rupture of muscular fibre, but a separation of one layer from the ad- joining one; in such cases, the detached por- tion is said to be reproduced the next year. From its smoothness it is able to penetrate into very small openings, and it delights to burrow in soft dry soil, and under decaying wood and leaves; it moves by lateral contractions, and sheds its skin, according to Bell, like the true snakes. It is ovo-viviparous, the young being brought forth alive in June or July, to the num- ber of from 7 to 14. The general color is a brownish gray, with a silvery glance, with seve- ral parallel longitudinal rows of dark spots on the sides, and one along the middle of the back ; the length is from 10 to 14 inches, of which the head is about half an inch. Its food consists of worms, insects, and small terrestrial mol- lusks ; it is not fond of the water. In France it is called Vorvet. The blindworm approaches the ophidians in its form, manner of progres- sion, absence of feet, number of ribs, and in- equality of lung development ; but it belongs to the scineoid saurians by the structure of the tongue, head, and jaws, by the occurrence of movable eyelids, and by the peculiarities of the vertebral column. BLISTER, a topical application, which, ap- plied to the skin, produces an irritation, and raises the cuticle in the form of a vesicle filled with serous fluid. The powder of the dried cantharis, or Spanish fly, operates rapidly, with certainty, and is now invariably used for this purpose. (See OANTHAEIDES.) Morbid action in one part of the organism may often be re- lieved or removed by counter-irritation in an- other and a neighboring part, and on this prin- ciple the blister is applied. When the imme- diate effect of a blister is required, the vinegar of cantharides is a very prompt and effectual application. A piece of blotting paper moist- ened with this fluid raises a blister almost im- mediately. It is sometimes thus applied behind the ears in toothache, or over the stomach in cases of sudden cramp. The raw surface pro- duced in this manner affords a ready means of introducing certain medicinal substances into the system by absorption; morphine, for in- stance, sprinkled on this raw surface, is quickly absorbed, and patients may be thus relieved where remedies could not be otherwise em- ployed, as in colic and cholera. IM.OCll. JlarkDS Elieser, a German naturalist, of
- Jewish parentage, born at Anspach in 1723,
i died in Berlin, Aug. 6, 1799. On arriving at manhood he was almost illiterate, but then thoroughly learned German arid Latin and de- voted himself to medical and scientific studies, taking the degree of M. D. at Frankfort-on-the- Oder. He practised his profession for many years in Berlin, and wrote several medical treatises; but his great work was one on ichthyology (Allgemeine Natvrgeschichte der Fische, 12 vols., Berlin, 1782-'95), excellently illustrated, which was in its time of great value. He made a fine collection of specimens, which is now in the Berlin zoological museum. BLOCK, Hanriee, a French political economist, born in Berlin, Feb. 18, 1816. He was taken to France at the age of five years, and is a naturalized French citizen. In 1843 he was appointed to a position in the statistical bureau of the ministry of agriculture, commerce, and public works, which he resigned in 1861 to de- vote himself exclusively to authorship. His chief works are: Des charges de I' agriculture dans les divers pays de V Europe (Paris, 1850) ; L'Espagne en 1850 ; Statistiyue de la France (1860) ; Puissance comparee des divers tats de r Europe (1862); Les finances de France de- puis 1815 (1863); Les theoriciens du sociii- lisme en Allemagne (1872); and Annuaire de V 'administration francaise, which he began in 1858, and continued several years. He has written largely for periodicals on statistics and political economy, and has edited journals de- voted to those subjects. In 1861 the academy of sciences gave him the Monthyon prize for statistics. BLOCKADE, in international law, the closing of an enemy's port by a besieging force. It has been described by Sir William Scott as " a sort of circumvallation round a place, by which all foreign connection and correspondence is, as far as human power can effect it, to be en- tirely cut off." The circumstances essential to a valid blockade are tolerably well settled by the decisions of eminent jurists in prize cases. The first of these is that a state of war must exist, though this may be without an actual declaration of war, for the blockade may be the first hostile act. The second is that it be sustained by a blockading force sufficient to make it hazardous to attempt to enter or de- part from the port, although if the ships com- posing it be for any short time driven from their positions by sudden tempest or other similar cause, the blockade is not thereby raised. The purpose of this measure is to in- flict injury upon an enemy, either by reducing the place, or by weakening his power of resist- ance by cutting off his supplies, or both ; but as a considerable proportion of the injury must fall upon neutrals, the belligerent is justly required to make his blockade what the term imports, and neither would neutral nations submit to it if he did not, nor would the prize courts sanc- tion the captures which might be made for
