Page:Encyclopædia Britannica, Ninth Edition, v. 20.djvu/311

Rh R A T R A U 293 wards, under Gioberti, he became minister of the interior, and on the retirement of the last-named in 1849 he be- came practically the head of the Government. The defeat at Novara compelled the resignation of Rattazzi in March 1849. His election as president of the chamber in 1852 was one of the earliest results of the so-called " connubio " with Cavour, and having become minister of justice in 1853 he in that and the next following years was able to carry a number of measures of reform of considerable importance, including that for the suppression of certain of the monastic orders. During a momentary reaction of public opinion he resigned office in 1858, but again entered the cabinet under La Marmora in 1859 as minister of the interior. In consequence of the cession of Nice and Savoy he again retired in January 1 860. He was entrusted with the formation of a new ministry in March 1862, but in consequence of his policy of repression towards Garibaldi was driven from office in the following December. He was again prime minister in 1867, from April to October. His death took place at Frosinone on 5th June 1873. (See ITALY, vol. xiii. p. 488 sq.) RATTLESNAKE. Rattlesnakes are a small group of the family of Pit -vipers (Crotalidae), characterized by a tail which terminates in a chain of horny, loosely con- nected rings, the so-called "rattle." The "pit" by which the family is distinguished from the ordinary vipers is a deep depression in the integument of the sides of the snout, between the nostrils and the eye ; its physiological function is unknown. The rattle is a complicated and highly specialized organ, developed from the simple conical scale or epidermal spine, which in the majority of snakes forms the termination of the general integument of the tail. The bone by which the root of the rattle is supported consists of the last caudal vertebrae, from three to eight in number, which are enlarged, dilated, compressed, and coalesced (fig. 1, a). This bone is covered with thick and Rattle of Rattlesnake (after Czermak). Fig. 1. Caudal vertebrae, the last coalesced in a single bone a. Fig. 2. End of tail (rattle removed) ; a, cuticular matrix covering terminal bone. Pig. 3. Side view of a rattle ; c and d the oldest, a and 6 the youngest joints. Fig. 4. A rattle with joints disconnected ; x fits into b and is covered by it ; z into d in like manner. vascular cutis, transversely divided by two constrictions into three portions, of which the proximal is larger than the median, and the median much larger than the distal (fig. 2, a). This cuticular portion constitutes the matrix of a horny epidermoid covering which closely fits the shape of the underlying soft part and which is the first commencement of the rattle, as it appears in very young rattlesnakes before they have shed their skin for the first time. When the period of a renewal of the skin approaches a new covering of the extremity of the tail is formed below the old one, but the latter, instead of being cast off with the remainder of the epidermis, is retained by the posterior swelling of the end of the tail, forming now the first loose joint of the rattle. This process is repeated on succeeding exuviations, the new joints being always larger than the old ones as long as the snake grows (fig. 3). Perfect rattles therefore taper towards the point, but generally the oldest (terminal) joints wear away in time and are lost. As rattlesnakes shed their skins more than once every year, the number of joints of the rattle does not indicate the age of the animal but the number of exuvia- tions which it has undergone. The lar-gest rattle in the British Museum has twenty-one joints. The rattle (fig. 4) consists thus of a variable number of dry, hard, horny cup-shaped joints, each of which loosely grasps a portion of the preceding, and all of which are capable of being shaken against each other. If the interspaces between the joints are filled with water, as often happens in wet weather, no noise can be produced. The motor power lies in the lateral muscles of the tail, by which a vibratory motion is communicated to the rattle, the noise produced being similar to that of a weak child's rattle and percep- tible at a distance of from 10 to 20 yards. The habit of violently and rapidly agitating the tail is by no means peculiar to the rattlesnake, but has been observed in other venomous as well as innocuous snakes with the ordinary termination of the tail, when under the influence of fear or anger. The special object for which the rattle has been developed in these snakes is unknown. Rattlesnakes are entirely confined to the New "World. North-American authors distinguish now a great number of different kinds, the most recent, Garman (Reptiles and Batrachians of North America, 1883, 4to), enumerating twelve distinct species and thirteen additional varieties ; but all these species or varieties fall into two groups, viz., one which has the upper side of the head covered with the ordinary nine dermal shields, and the other in which the shields between and behind the eyes are broken up or replaced by small scales. The former group consists of two species only, of comparatively small size, both North American, Crotalus miliarius being the more generally known. The second group comprises the more formidable kinds of South as well as North America, which are gener- ally described under the names of C. horridus and C. durissus. In the older standard works the former name was applied to the southern form, which extends from Paraguay and Chili through Brazil into Mexico, and the latter to the common North -American rattlesnake; in modern American works this nomenclature is reversed. C. horridus and C. durissus belong to the most danger- ous of poisonous snakes. If a person bitten by an adult rattlesnake escapes with life, protracted illness and the loss of or injury to the wounded limb are frequently the consequence. They inhabit localities to which the sun has free access, prairies, rough stony ground, fec. Specimens of 5 feet in length are not rare. Formerly common in the eastern parts of the United States, and still so in thinly inhabited districts of the western States, rattlesnakes, like the vipers of Europe, have gradually succumbed to the unceasing persecution of man. They vary much in colour : a common type of coloration is a brownish ground-colour, sometimes yellowish, sometimes blackish. Series of large dark spots, frequently edged with yellow, and of very variable shape, run along the back and sides. The head and neck are ornamented with dark or black longitudinal bands, or are marked by an almost uniform coloration. RAU, KARL HEINEICH (1792-1870), German political economist, was born at Erlangen on 23d November 1792. He pursued his studies, devoting himself principally to the (so-called) cameralistic sciences, from 1808 to 1812 at the university of his native place, where he afterwards remained as a privat-docent. In 1814 he obtained the prize offered by the academy of Gottingen for the best treatment