M E S 



[ 288 ] 



MET 



of the peritoneum. This is a fine 

 and delicate membrane which con- 

 nects the intestines to the spine, 

 and to each other, and which ap- 

 pears to be interposed in order to 

 allow to the intestines that freedom 

 of motion which is so necessary to 

 the proper performance of their 

 functions. 



MESENTE'BIC. Pertaining to the me- 

 sentery, as the mesenteric glands, 

 &c. 



MESOTHO'BAX. (from ^teo-o?, middle, 

 and Owpag, chest.) In entomology, 

 the mesothorax gives origin to the 

 second pair of legs, and also the 

 first pair of wings, or to the elytra, 

 of insects. 



ME'SOTYPE. (from ^e'<roe, middle, and 

 TV??, form.) Prismatic zeolite ; 

 a simple mineral of the zeolite 

 family, occurring in drusy cavities, 

 or in veins in secondary trap rocks. 

 Mesotype is of a white, red, yellow, 

 or yellowish-brown colour. It 

 occurs regularly crystallized. It 

 consists of silica 54' 40, alumina 

 19-75, soda 15-05, lime 1'60, water 

 9-80. Specific gravity 2-3. 



MESOZ'OIC. A palseontological term, 

 corresponding to, or synonymous 

 with, secondary. The Mesozoic, or 

 secondary, epoch comprises the cre- 

 taceous, the oolitic, and the triassic 

 periods. 



METACA'BPAL. Belonging to the wrist ; 

 as the metaca/rpal bones, &c. 



METACARPUS, (from /tera, with, and 

 Kapiro-s, the wrist.) That part of 

 the superior extremity which con- 

 nects the wrist with the fingers ; 

 commonly known as the hand, but 

 not including either the wrist or 

 the fingers. 



METABO'LIANS. (from fjucT-apaXXw, Gr. 

 to change.) That sub-class of in- 

 sects which undergo a metamor- 

 phosis, and are usually fitted with 

 wings in their final state. 



ME'TAL. (/uera\\ov, Gr. metattum, 

 Lat. metal, Fr. metdllo, It. metall, 

 Ger m . ) "A metal may be described 



as a shining opaque body, a good 

 conductor of heat and electricity, 

 insoluble in water ; capable, when 

 in a state of oxide, of uniting with 

 acids, and of forming with them 

 metallic salts." Phillips. Metals, 

 as presented by nature, are some- 

 times pure, or combined with each 

 other only, and are said to exist in 

 a metallic state. But more fre- 

 quently they are combined with 

 oxygen, sulphur, &c., by which 

 their peculiar metallic properties 

 are more or less disguised ; in this 

 case the metal is said to be mine- 

 ralized, and the oxygen, or sulphur, 

 is called the mineralizer. All the 

 individuals of the class of metals, 

 with the exception perhaps of iron, 

 are perfectly inert and harmless; 

 even arsenic, lead, copper, and 

 mercury, which in certain states 

 of combination constitute some of 

 the most virulent of known sub- 

 stances, exert no action upon the 

 living system, unless they be in 

 union with some other body ; but 

 when so united, how valuable do 

 they become, and what various 

 medicinal effects may they not be 

 made to produce ! The metals at 

 present known are forty-four in 

 number. Of these, seven were 

 known in the earliest ages, and, in 

 consequence of a superstitious belief 

 in the influence of the stars over 

 human affairs, were first distin- 

 guished by the names and signs of 

 the planets ; and as the latter were 

 supposed to hold dominion over time, 

 so were astrologers led to believe 

 that some, more than others, had 

 an influence on certain days of the 

 week; and, moreover, that they 

 could impart to the corresponding 

 metals considerable efficacy upon 

 the particular days which were 

 devoted to them. As regards the 

 ages of metals, tin, molybdena, 

 tungsten, and wolfram, are ranked 

 as the most ancient ; uranium and 

 bismuth succeed. Gold and copper 



