602 A MANUAL OF PHYSIOLOGY 



induced pneumococcus infections run a milder course. These 

 bacteriological results are supported to a certain extent by clinical 

 experience. For it has been observed that a cholera patient 

 with distinct fever has a better chance of recovery than a case 

 which shows no fever. But too much weight ought not to be 

 given to isolated facts of this sort, and adverse evidence can be 

 produced both from the laboratory and the hospital. For 

 although hens are immune to anthrax under ordinary conditions, 

 but can be infected by inoculation when artificially cooled, frogs, 

 equally immune at the temperature of the air, become susceptible 

 when artificially heated. And it is impossible to deny that the 

 use of cold baths in typhoid fever is sometimes of remarkable 

 benefit. 



Distribution of Heat Temperature Topography. The great 

 foci of heat-formation the muscles and glands would, if heat 

 were not constantly leaving them, in a short time become much 

 warmer than the rest of the body ; while structures like the 

 bones, skin, and adipose tissue, in which chemical change and 

 heat-production are slow, would soon cool down to a temperature 

 not much exceeding that of the air. The circulation of the 

 blood insures that heat produced in any organ shall be carried 

 away and speedily distributed over the whole body ; while 

 direct conduction also plays a considerable part in maintaining 

 an approximately uniform temperature. The uniformity, how- 

 ever, is only approximate. The temperature of the liver is 

 several degrees higher than that of the skin, and the temperature 

 of the brain several degrees higher than that of the cornea. 

 The blood of the superficial veins is colder than that of the 

 corresponding arteries. 



The crural vein, for example, carries colder blood than the crural 

 artery, and the external jugular than the carotid. The heat pro- 

 duced in the deeper parts of the regions which they drain is more 

 than counterbalanced by the heat lost in the more superficial parts. 

 When loss of heat from the surface is sufficiently diminished by an 

 artificial covering, or prevented by the protected situation of any 

 organ with an active metabolism, the venous blood leaving it is 

 warmer than the arterial blood coming to it. The temperature of 

 the blood passing from the levator labii superioris muscle of the 

 horse during mastication may be sensibly higher than that of the 

 blood which feeds it ; the blood in the vena profunda femoris, and 

 in the crural vein of a dog with the leg wrapped in cotton-wool, is 

 warmer by o'i to o'3 than the blood of the crural artery. This 

 difference of temperature is due to the heat produced in the muscles, 

 and it is not difficult to show that the difference ought to be of this 

 order of magnitude. The quantity of blood in a y-kilo dog is about 

 kilo ; j- of this, or kilo, is in the skeletal muscles, and the average 

 circulation -time through them may be taken as ten seconds. Six 

 times in the minute, or 360 times in the hour, |- kilo of blood passes 

 through the muscles, and is heated on the average by o'2. If we 



