LACTIC BTUER. 



LAKES 



fi^--'- 1 i J is also obtained by the action of Uctio acid 



en SBMia ft is interesting as being identical in composition with 

 three other bodies, alanine, earcoaine, and urethane (carbamate of the 

 of ethyl). They have all of them, however, Terr distinct 

 L This substance differs from the others in yielding Uctio 



lame ; hence it* name. 



i whoo acted on by Midi and 

 >y sahibls in alcohol and water, and crystallise* in plate, or 



adJ. In OTmHmtifffl with ammonia, results from the 

 the dry ga* upon lactic anhydride. The salt contains 





_ of lactic acid. One or two equivalent* of the 

 in lactic acid may be replaced by one or two equivalent* of 

 aing respectively acid and neutral salt* ; the Utter are more 

 stable than the farmer. The salt* of the alkalies do not crystallise ; 

 those of baryta and lime with difficulty ; that of xiuc (neutral) in 



The true cvutilnfo* of lactic acid is not yet clearly determined. 

 Wurta has recently succeeded in obtaining a lactic ttkrr which may be 

 aid to contain four equivalents of ethyl in the place of an equal 

 number of hydrogen in lactic acid. Wurtz, however, considers that 

 lactic acid is the alcohol of a biatomic radical Uid : /l (C.H.O,), and Is 

 thus formulated : 



C.H.O,- 1 Q 

 HH /"* 



In addition to lactic ether just mentioned, Wurtz has obtained laoto- 

 butyric ether by the re-action of chturolacli: tther (C.H.O.", C.H,, 

 O.O,) on butyrato of potash. The following are his formula; for 

 these two ether* : 



WH 1. cWcnl. 



,11,, C,H, J 0,0,0,, C,IIj ) 



! 



Lutobatvrio ctber. 



Corresponding metallic derivatives are said to have been produced 

 but not without difficulty in the case of the second atom of hydrogen 

 in the Uotic acid as represented by Wurtx. Those containing one 

 atom only of hydrogen replaced correspond to the salts already men- 

 tioned under the name of neutral salts of lactic acid ; while the acid 

 aaHa described at the same place would, under Wurta's view, some- 

 what neemlihi quadroxalatei, and be derived from a double equivalent 

 of his lactic acid by substitution of an atom of metal for one of 



. 

 LA : 



LACTIC ETHER. [LACTIC ACID; ETRERIAL SALTS.] 

 II'E. [LACTIC ACID.] 



LACTIX. (SI-GAB; Suyar & Milt.] 



LACTOllfTYIMi KTHKK. [LACTIC AciD.] 

 TONE. ID .J 



LACTOSE. [SI-OAR ; Sugar of Hill.} 



LACTL'CARIUM, the medical uses of, are sufficiently described 

 under this bead in the NAT. Hi-r Div. 



LA' i the active principle of the Laetufa, riron, or wild 



lettuce. It U obtained from the juice of this plant, which U called 

 Uotocarium. It U a bitter, crystalline, resiuoid substance, pos- 

 seting anodyne properties. 



(CJEL^Otl A crystallisable principle contained in 

 the jiuee of the wild lettuce (Lacica, rtrosu). It i* insoluble in water, 

 but very soluble in alcohol and ether. It possesses neither acid nor 

 alk^Une properties. 



ITL. [LACTIC Acm] 



LADANUM. (C M H M 0.). A resinous body which exudes from the 

 shrub OMfu crrtira*. It is a black tenacious solid which softens 

 between the fingers and diffuses an odour resembling ambergris. 



1 >KB, the portion of a scaffolding by means of which workmen 

 are enabled to pa*, from one level to another; and any steep staircase*, 

 with extremely narrow treads, such as are used in mines, factories. 

 or warehouses, or even in ships' holds, are known by the name of 

 ladders. The principal distinction between Udders and staircases 

 appears to consist mainly in this namely, that with staircases there is 

 *> necessity for using the hands whilst mounting or descending, 

 whereas with Udders it would not be possible to maintain a footing 

 without at the setae time hoidmc either the side., or the roundsTwith 

 the hand. The parts of a ladder are, simply, He Mn, which are 

 u*u*Uy made of round Or-potes eat down the middle (and in England 

 used with the convex aides outwards, whilst on the Continent the flat 

 outwards) ; At rvttmU, usually made of 



. 



oak,W*eirular section, rathsr larger in diameter in the middle and 

 tapering towards the aUss, and fastened to the said sides by fox- 

 "*ts; as* oeeeajoMlIy iron cross-tie* are inserted, in order to resist 

 sayUodeocT on the part of the side, to s 



inserted, in order to resist 

 spread. The distance apart 



. I, :, 



BeteM. no* ,*sraUy edopfl, I * eeUbUfag at Uart. 



There are snot* modlncetioM of bvldor* need in par 

 "***""'* paiour,' bdd^ -ad. onHf 



squared 



and with 



paiour,' bdd 

 bin*, at the top ; and u 

 at the baX'and fUt 



they, and the companion ladders of ships, ought more correctly to be 

 cUased as staircases. The chain of bucket* of a dredging-machine is 

 also at times called a " ladder." 



In the cathedral of Nurenberg the idea of the ladder has been 

 admirably converted into an architectural decoration in the detail* *>f 

 the canopy of the pulpit; and it may indeed be observed, that 

 story of the Udder perceived by Jacob in his dream is one which 

 would have very probably suggested its introduction into ecclesiastical 

 decoration. The designer and sculptor of the Nurenberg pulpit was 

 Adam Kraft, who flourished about the end of the 15th century. 



I.AIHM;. niu. <>K. [Hiu. t,t I.M., 



I. MIC ACID. [TABTAHIC Aero.] 



l..KYiiTAUTAKIr ACID. [TABTABIC ACII>.| 



LAGOON, or LAOUNE. Lagoons are sheets of water formed 

 either by the encroachment* of rivers or seas upon the land, or by the 

 separation of a portion of the sea by the intervention of a bank. Thus 

 there are fluvial and marine lagoons. When the laud on either side of 

 a river's course is lower than the immediate bank* of the stream, and 

 the river, in the season of the floods, either overflows it* banks or in 

 part breaks them down, the water inundates the low land ; and if on 

 the subsidence of the flood the water again flows back into ii..- <-hannel, 

 the lagoon is merely temporary, and is simply an inundation. This, 

 according to circumstances, may be a benefit to the count! \ 

 disaster. Inundations are a U-nrtit when they Lrini; with tin-in and 

 deposit a rich vegetable humus, which, on being cultivated, 

 abundant crops ; to such deposits Lower Egypt owe* it* great fertility. 

 Inundations of this kind either diminish or increase annually, i 

 repeated deposits, the soil becomes raised ; and unless the bed 

 river rise in proportion, the water is eventually kept within its channel ; 

 but if, on the contrary, the bed rise, the inundation gains every year 

 in extent of surface what it loses in depth of water. Should the 

 inundation however, instead of a prolific mud, bring nothing but sand 

 and stones, then, as has been frequently experienced in It.: 

 inundations are a cruel disaster, for they condemn rich lands to eternal 

 barrenness and .sterility. If the configuration of the land and other 

 circumstances prevent the water of the inundated parts from flowing 

 back on the subsidence of the flood, then a permanent lagoon in formed, 

 and the land thug laid under water can only be recovered at a great 

 expense, even if that be possible. These lagoon* are generally fatal to 

 the neighbourhood, for the water in them, being stagnant, gives rise to 

 unwholesome miasmata, producing agues and other ma! 

 orders. Such lagoons are not absolutely confined to the lower (tarts of 

 water-courses, though it is in such places that they are most frequently 

 met with. Fluvial lagoons are sometimes formed by infiltration ; a 

 remarkable instance of which U the marshy lagoon of Ybora, on the 

 Parana, in South America. 



Marine lagoons are much more common than those on the borders 

 of rivers. They are formed sometimes by the encroachments of the 

 sea, and sometimes by the throwing up of a bar or bank, which 

 eventually divides off a portion of the sea altogether, or leaves merely 

 a small opening. In Europe there arc many marine lagoon 

 Adriatic, on its north and north-western parts particularly, is full o 

 them. The Zuyder Zee is a vast lagoon. There are also two very 

 large ones known by the names of the Frische Haff and the Curische 

 Half, at the south-east angle of the Baltic See, In the Sea ot 

 there is the Sivasoh or Putrid Sea. On the east coast of Smith 

 America there are some very Urge lagoons, and they abound at the 

 bottom of the Mexican Qulf. Marine lagoons can never be useful unless 

 when sufficiently Urge and deep to admit of being navigated, in wlii<-li 

 case they form secure harbours. When shallow, they give out 

 exhalations like fluvial lagoons, as is too well known in Venice, which 

 in l.nilt on the 80 islands of the lagoon at the extremity of the gulf; 

 though iu this case much of the evil arises undoubtedly from the 

 circumstance of the lagoon being the receptacle of all the filth of 

 the city. 



LAITY, persons not clergy; that is, the whole population except 



those who are in holy orders. All the lexicographers, we believe, 



agree in deriving it from the Ureek word law (Aods), the people. A 



i* one of the laity. The terms are not used except when the 



minil in din etui t tion of the two classes. 



1..VKKS. IC.n.ciriuxi: MATTHIX] 



LAKES are in the land what islands are in the sea; they are sur- 

 rounded on all sides by land, as islands are by water. They are sheets 

 of water of greater or less extent, and differ from lagoons in 

 origin, and from tanks and reservoirs by their being naturally f< 

 whereas the Utter are the works of nun. .Is and pool 



not no easy to distinguish them, it being difficult to draw the line 

 between a large pond and a small lake. The feature l>y \\hirh | 



uld lie lie-t, iliKtinguished is this, that a lake is fed by streams 



either flowing at the urface of the soil or subterraneous, while a pond, 



i large, is only the accumulation of rain-water in some hollow. 



Thus ponds arc u . up in hot weather, while true lakes are 



only temporarily diminished by neat. 



Lakes have sometimes been divided into fresh-water lakes and salt- 

 water lakes ; though here again it is not easy to draw the line between 

 the two, as from the freshest to the most salt the degrees of saltnees 

 are very various. 



The principal difference in lakes is this : some have no apparent 



