526 MATERIA MEDIC A AND THERAPEUTICS. 



tion concern us here, viz. (1) excessive sweating, and (2) deficient 

 sweating. 



1. Excessive sweating, hidrosis, hyperidrosis, is found in a 

 great variety of morbid conditions. In some kinds of fever, such 

 as rheumatism, its pathology is bound up with the pathology of 

 the fever as a whole. In disorders of respiration, as we have seen, 

 dyspnceal sweats are due to stimulation of the sweat-centres by 

 venous blood. The " cold " sweats of wasting diseases such as 

 phthisis, especially during sleep, appear to be due to the same 

 cause, associated with anaemia and coldness of the skin, which 

 prevent evaporation and "insensible perspiration," and thus 

 give rise to a profuse collection of visible sweat as well as 

 great depression of the bodily strength from interference with 

 the cutaneous excretion. " Critical " sweats are referred to 

 sudden changes in the disturbance of the vaso-motor system of 

 the skin present in fever. Toxic sweating, as is seen in 

 alcoholism and gout, may obviously be variously induced. 



2. Deficient sweating : anhidrosis. Dryness of the skin occurs 

 at the beginning of most fevers, and throughout the course of 

 most of them more or less interruptedly. It is also marked in 

 some diseases and disorders of the urinary functions, such as 

 Blight's disease and diabetes ; in certain diseases of the skin 

 itself ; and as the result of poisoning by atropia (belladonna), 

 etc. Manifestly different parts of the nervo-glandular apparatus 

 are disordered in the different cases. 



IV. NATURAL RECOVERY. 



Disorders of the body heat being disturbances of a regula- 

 ting mechanism, that is, of one means of natural recovery, we 

 can hardly expect to find at work in fever those very provisions 

 which have been interfered with. For the same reason, the 

 temperature of the body generally returns to the normal on 

 the cessation of the cause of the fever, either spontaneously or 

 with the artificial assistance of the therapeutist. Occasionally 

 the temperature rises beyond all control to 107, 110, and 

 even higher, and the subject dies of the effects of excessive 

 heat or hyperpyrexia. In most instances of death from fever, 

 however, the fatal result is due to one of the other factors of 

 fever, especially the body waste. 



V. THERAPEUTICS. 



A great part of our knowledge of the body heat, its regula- 

 tion and its disturbances, has been derived from careful obser- 

 vation of the results of treatment ; and the use of measures to 

 control fever antipyretics or febrifuges (febris, fever, and 



