30 FIELD ORNITHOLOGY part i 



draught of air, the rest of the surface remaining at an ordinary 

 temperature ; or if the temperature of the whole be suddenly 

 changed by going out into the cold, or by coming into a warm room, 

 there is much liability of trouble. There is an old saying — 



When the air comes through a hole 

 Say your prayers to save your soul ; 



and I should think almost any one could get " a cold " with a 

 spoonful of water on the wrist held to a key-hole. Singular as it 

 may seem, sudden warming when cold is more dangerous than the 

 reverse ; every one has noticed how soon the handkerchief is 

 required on entering a heated room on a cold day. Frost-bite offers 

 an extreme illustration of this. As the Irishman said on picking 

 himself up, it was not the fall, but stopping so quickly, that hurt 

 him ; it is not the gradual lowering of the temperature to the 

 freezing-point, but its subsequent sudden elevation, that devitalises 

 the tissue. This is why rubbing with snow, or bathing in cold 

 water, is required to restore safely a frozen part ; the arrested 

 circulation must be very gradually re-established, or inflammation, 

 j^erhaps mortification, ensues. General precautions against taking 

 cold are almost self-evident in this light. There is ordinarily little 

 if any danger to be apprehended from wet clothes, so long as 

 exercise is kept up ; for the glow compensates for the extra cooling 

 by evaporation. Nor is a complete drenching more likely to be 

 injurious than wetting of one part. But never sit still wet ; and 

 in changing rub the body dry. There is a general tendency, 

 springing from fatigue, indolence, or indifference, to neglect damp 

 feet ; that is to say, to dry them by the fire ; but this process is 

 tedious and uncertain. I would say especially, off with the muddy 

 boots and sodden socks at once ; dry stockings and slippers, after a 

 hunt, may make just the difference of your being able to go out 

 again or never. Take care never to check perspiration ; during 

 this process, the body is in a somewhat critical condition, and 

 sudden arrest of the function may result disastrously, even fatally. 

 One part of the business of perspiration is to equalise bodily 

 'temperature, and it must not be interfered with. The secret of 

 much that might be said about hathing when heated lies here. A 

 person overheated, panting it may be, with throbbing temples, and 

 a dry skin, is in danger partly because the natural cooling by 

 evaporation from the skin is denied, and this condition is sometimes 

 not far from a sunstroke. Under these circumstances, a person of 

 fairly good constitution may plunge into the water with impunity, 

 even with benefit. But if the body be already cooling by sweating, 

 rapid abstraction of heat from the surface may cause internal 

 congestion, never unattended with danger. Drinking ice -water 



