INCUBATION MYSTERIES

New Zealand Mail, 22 January 1902, Page 55

INCUBATION MYSTERIES

Rare indeed aro the instances in which man can not only take liberties with tho mysterious laws of nature, but actually improve upon their method of working; yet this is what those who carry on the process of artificial incubation claim to do. They can rely with a greater degree of certainty on producing a chicken from a fertile egg by mechanical aid than by consigning its pale shape to the nest of a sitting hen; for a lien, however staid her demeanour, or having feathers bristling with maternity, is bu a fickle creature, and may quit her cosy seat at any moment, leaving her unfledged offspring to perish in their shells. An incubator plays no such vagaries ; it is a passive object from which will issue in due. course the protesting chirrup of the “piping” chiek : Although artificial incubation, as a general pursuit, is quite modern, tho idea of it dates back into very remote ages. The dusky subjects of the Pharoahs practised it, not indeed as we do, but in great sand ovens known as “mohmals.” The Chinese of the period of Confucius also hatched eggs—as they still do in certain parts of the Celestial Empire when not occupied in less peaceful avocation—entirely by the heat of the sun.

We cannot suppose that any hen at all of a particularly contemplative turn of mind looks with particular favour upon the artificial incubator. It simply represents a cool—or, more strictly speaking, a warm—usurpation of her own legitimate rights. Whilst she still remains very much in request as an egg-producing member of society, she is rapidly being discarded as a mother. Indeed, to such an extent is this true, that those comparatively few poultry breeders, who still remain 'conservative to the natural method of hatching will tell you how each successive season the difficulty of procuring

broody liens becomes greater a.id ; . ... . er; and the reason or this :s , ibie enough. The vast m;: r people who keep poultry in a , ~y merely topsupply the require;i:e..cs : f their households do not waai. to t_<,> troubled with fowls that are hubu-md/ falling broody; one incubator will enable them to replenish their stock abundantly. So the varieties of hens which are most productive cf motherly specimens are being gradually eliminated and the non-sitting varieties bred more and more exclusively. The chicken of the future will be a mechanically produced creature, whose sole mission in life will be either to lay eggs or repose upon a parsley garnished dish. It. would be an interesting speculation for one fond of psychological problems to try and determine how many generations of hens must be hatched by artificial incubation in order to effectually destroy tho maternal instinct within the species.

The artificial incubator, as a mere piece of mechanism, is a very simple structure. The conditions it has to fulfil are of such a comparatively elementary character that it could scarcely be otherwise. The maintenance of a uniform degree of temperature over a given period is the main essential, and a lamp radiating its heat into a closed box will effect this in principle. True, a considerable amount- of ingenuity has been displayed in tho invention of appliances for automatically controlling the heat, so that it will be maintained at an exact given point; for the normal hatching temperature of a lien’s egg is about 104 deg. Fahrenheit, and any considerable fluctuations above or below this would effectually arrest the process of germination. The method by which the heat of most types cf incubators is controlled at the present day is through the action of a little metallic capsule, charged with a volatile liquid, which expands and bulges upwards when the requisite ■ temperature is readied, thus moving : delicate levers, which lift a damper | upon tho lamp chimney, and by this - means the surplus heat is allowed to | escape.

The incubator at the hatching period is a strange and interesting spectacle to those who behold it for the first time. You catch the sound of muffled chirruping coming from inside, and when you pull open the egg drawer you witness a singular confusion of broken shells, and the struggling draggled-looking shapes of newly-hatched chicks, with here and there a gaping beak just emerging from, the shell. There is a sense of mystery about it all —this creation of life, so to speak, through the instrumentality of man’s handiwork—which cannot fail to impress the thoughtful observer.