15



The Grey-necked Serin-finch is the last species treated of in the

present number.


Dr. Butler is to be congratulated on the care and accuracy with which

he has done his work. He has shewn us that a popular book need not be

either unscientific or inaccurate. Should the succeeding parts prove equal

to the first, “Foreign Finches in Captivity ” will, undoubtedly, take the

very highest rank among works on Aviculture.


C. S. Simpson.



EGG-PRODUCTION AND EGG-BINDING.


By C. S. Simpson, D.R.C.P., M.R.C.S.


To those Aviculturists who have kept birds (at any rate foreign birds)

for any length of time, the title of my paper will at once raise various

gloom)'recollections. Probably the complaint of egg-binding is the cause

of more deaths than any other disease to which such birds are liable in

confinement. It is peculiarly disappointing, too, to the amateur, from the

fact that it necessarily occurs at a time when he is indulging in pleasant

anticipations of seeing his birds successfully rear a family, a prospect which

must always excite the keenest interest in everyone worthy of the name

of Aviculturist.


What is the cause of egg-binding ? Can we prevent it ? And how are

we to treat a bird suffering from the disease ?


If we dissect the body of a hen bird during the breeding season

we shall find, after carefully removing the bowels and liver, at the back

of the abdominal cavity, and on the left of the spine, a body which is

generally compared to a tiny bunch of grapes. This is the ovary, and

the little separate bodies corresponding to the grapes are the partly

developed eggs or ova, each of which is contained in a delicate membrane

or capsule. There are two ovaries, but the right one is almost always

atrophied. A convoluted tube leads downward from the ovary, and opens

into a cavity called the cloaca, which is formed by the dilated end of the

bowel, and which communicates with the exterior by means of the ventral

orifice. This tube is called the oviduct, and its purpose is to conduct the

ovum when ripe to the exterior of the body. The wall of the oviduct con¬

tains muscular fibres, which have the function of contracting the calibre of

the tube, and so driving the egg down it. A number of little glands are

also contained in the oviduct, the mouths of which open upon its inner

surface, and these manufacture both the “ white ” and the shell of the egg.


If we dissect a hen bird during the moulting season, or before pairing

has commenced, we shall probably conclude at first sight that the ovary is

absent. If, however, we have carefully noted its position in our previous

dissection we shall be able to find it, but in a very small and undeveloped

condition.


The conditions which stimulate the egg-producing organs, and cause

them to develop are (ist), the approach of that time of the year at which

pairing takes place, and which normally coincides with (2nd) the advent of

warm weather; (3rd), the presence of the male bird, who at this time

endeavours, by all the arts at his disposal, to attract and excite the female,

and (4th) access to a suitable site and suitable materials for nesting.


When an ovum becomes ripe, its capsule bursts, it passes into the

upper expanded end of the oviduct, and the latter contracts and presses it

onward towards the cloaca. Meanwhile, the glands are discharging their

contents. At the upper part of the oviduct the white is deposited around

the yolk, and at the lower part a white material containing lime salts is

poured out and forms the shell. This process occupies from 12 to 24 hours,

and, at its conclusion, the egg is completely formed, and is then expelled

from the cloaca, or in other words, “laid.”


Now, it is evident that this process of egg production is a com-



