AN INTERESTING. STUDY.

Auckland Star, Volume LXIX, Issue 225, 23 September 1938, Page 16

AN INTERESTING. STUDY.

THE INCUBATION PROCESS. Some readers may have been interested enough to break an egg on each day of incubation and after observing the contents to have separated the tiny embryo from the liquid which surrounds it, and to have immersed it in alcohol in a small glass bottle for future observation. After the first day there is a bulging prominence which is the forming cerebral vesicle, often mistakenly termed the eye. It is really the brain : and the eyes, or optic vesicles, again bulge out from either side of the cerebral vesicle as time goes on. Passing to the third day, further portions of brain are added in front of that already formed, but as yet there is no beak, nnd this will not appear until the brain growth is fully provided for. The head is, of course, greatly out of proportion to the entire body, which is as yet very small. This creamy white body is almost snail-like until \about the end of the fourth day, when the wings and legs begin to "bud" or sprout, but they have no distinctive shape, as this will only occur as growth proceeds. At this date also could be found the beginnings of the digestive organs, followed by the sexua! organs. It may be said that at the end of the first week the embryo is a miniature chicken and that it only reiiiuins for the various "buds" to open and take on their distinctive shapes—such as the bend in the wing, the elbow joint, I the hocks and the toes. The eves are always curious features, being greatly out of proportion to anything e;se, yet later they will be a relatively small part of the chicken. Those who have broken an egg about half way through the incubation per- ; iod will have noticed that the embryo has no feathers, but that on the body I are a number of small lines like short I pencil marks. These will eventually l become sheaths from which t!io down , which first covers the chicken is liberated.

An embryo a week old has some ino\ement and when the pw jg broken into a saucer the beak will open and shut in a gasping movement, or there will be a slight kick of the legs as the embryo dies.—W.H.