Eggs: the falsification of a theory

Sometimes a single finding may help to falsify an existing theory. I found this description of an unusual egg in The Veterinarian of 1851, vol 51. p.119.

A CURIOUS "CASE."

To the Editor of " The Lancet."

SIR, — I have lately received a communication from Dr. White, of the 13th Bengal cavalry, which may prove interesting to the readers of The Lancet. He states, " that a fowl belonging to an officer stationed at Peshawer laid an egg, so singular in appearance, on account of its great length (four inches) and narrowness, that he determined to preserve the shell. For this purpose he punctured the ends, intending to remove the interior by breathing forcibly through it; he was surprised to find the needle strike against a hard substance, and on shaking the egg he felt the more assured that it must contain something abnormal. On breaking the shell, another perfect egg was found, with a hardened shell, containing yolk and albumen, as in the first. We read of two eggs united at the ends by the membrana putaminisr and also of others containing a blasted ovum, double or triple yolks, &c.; but I believe this is the only authentic record of a perfect egg with hardened shell being found in the interior of one also normal; and it would seem to determine points on which some difference of opinion has existed among physiologists. Firstly, it proves that the shell of the egg is hardened without being exposed to the atmosphere, although it has been believed that the induration of the earthy deposit depends on the absorption of carbonic acid from atmospheric contact; as the exterior shell was perfect, this explanation can no longer be considered satisfactory. Secondly, that the membrana testae with its earthy envelope are both products of the oviduct, and that it is not the case, as has been affirmed by one author, that the shell is only an uterine secretion.

Your's obediently,

W. H. Ashley, M.D. Boyne- Terrace, Notting-hill, Oct. 1850.

This case requires some comments:

1. I am not familiar with the physiology of egg development in birds, but the way of reasoning of the authors looks OK to me: the theory of the hardening of the shell of the egg should be discarded. But was it? Was it the decisive blow to the theory? I do not think so; in scientific practice it does not work that way.

2. Why did mr Ashley send this case to the Lancet? Maybe the scientific status of The Veterinarian was so low that it was a waste of time to publish in it. Or maybe the intended reader, i.e. biologists of those days (Darwin among them?) were reading the Lancet, although it was in principle a medical journal.