A STUDY IN MORBID AND NORMAL PHYSIO LOGY. n 



ott from a body was M. de la Place. The first to apply the calorimeter to the 

 measuring of animal heat was M. Dulong, who detailed the account of his experi- 

 ments to the French Academy in 1822, but did not publislj it in full until IS-II 

 (Aniiules de cltimk et de plti/siqae, 3nie serie, tome i. p. 440). In June 1823 

 M. Despcrtz obtained a prize from the French Academy for his paper upon the 

 Causes of Animal Heat {Auiudes de diimie et de pJii/sique, tome xxvi. p. 337). In 

 1872 Dr. Senator {Arcluv far Auutoode, Phydoloyie und Wissensch. Medccin, p. 1) 

 gave to the world a very important paper, entitled Untersuchungen liber die \Var- 

 mebildung, in which he described a calorimeter differing from that previously 

 employed, in that the outer case was surrounded by a non-conducting medium. 

 I shall not enter into a detailed description of any of these instruments, as elaborate 

 historical matter is foreign to the intention of the present paper. It does, how- 

 ever, seem proper to state tliat the apparatus used by myself is similar in the general 

 principles of its construction to that employed by Senator. 



As some difficulty was met in making an apparatus which should stand the test 

 of continuous work, and as the value of the present memoir is dependent upon tiie 

 accuracy of the apparatus employed, a detailed account of it as finally perfected is 

 ofi'ered. 



The essential portion of the apparatus consists of a double metallic box, which 

 is placed in some non-conducting substance contained in a wooden case or box. 

 For the metal work the so-called "galvanized sheet-iron" was selected. It has 

 stood the test of three years' intermittent work without rusting, and is mucli less 

 expensive than copper. 



The inner box. which rests on feet, (PL II. fig. 1, A) has in the end a movable 

 circular lid (fig. 2, a) or door formed of heavy galvanized iron. Around the edge of 

 the opening upon which this door fits is a series of screw posts (fig. 2, B), and in the 

 lid are holes corresponding with these posts ; just inside the line of these orifices 

 is soldered a heavy wire. A piece of thick, soft rubber is also so shaped and per- 

 forated as to cover the box opening and to allow the posts to come through. When 

 the outer iron covering and this piece of rubber are in position, thumb-screw nuts 

 are tightly screwed down, so that the inner rim of the lid nips the india-rubber 

 and makes a thorouglily water-tiglit joint. 



The inner box (fig. 1, a) has running up from it at each end, a vertical ])ipe 

 (B), tipped with a brass flange joint, of such length that, when the apparatus is in 

 working position, it just reaches through the lid of the outer box, so that wlien a 

 nozzle is screwed firmly down upon a leather washer a water-tigiit joint is formed. 

 One of these pipes reaches nearly to the bottom of the inner box, the other opens 

 at the top. In this way air forced in through one and out through the other has 

 to circulate through the box. It is necessary to protect by heavy semicircular wires 

 the long tube so that the animal cannot disturb it. 



The outer box, also of galvanized iron, has a movable lid over its whole top. 

 Some difficulty was experienced in getting a joint which, wliilst allowing the lid to 

 be easily shifted, should be both durable and tight. The following device was 

 found to answer perfectly: The iron of the upright sides and ends of the outer 

 box is so bent at right angles, first outwards and then upwards, as to oiler a flat 



3 March, 18S0. 



