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.

To ascertain the state of the secretion

At the end of the 1970’s the Faculty of Veterinary Medicine of Utrecht University decided to introduce a course for first-year students that was called ‘animal handling’. The idea behind this was that more and more students started a veterinary training at the university who had no experience with such practical handling of animals such as walking with a horse, holding a rabbit and catching a chicken. Apparently, in the nineteenth century a similar problem was noticed in England; a mister Robert Read, from Crediton, devoted several pages of The Veterinarian to help young veterinarians who knew much but could little.¹ This is the beginning of the article:

“The anatomy and pathology of cattle and other domestic animals will not in itself form the completion of the study.

The tyro who steers from the College with a full share of the knowledge of the diseases of cattle, and launches forth into country practice, will have to surmount many obstacles ; more especially if he has not, in his younger days, been accustomed either to agriculture or to the habits of every kind of stock. To the young beginner or aspirant for country practice, who has scarcely, if ever, wandered from the busy city or fashionable town, a few hints may not, I hope, prove unwholesome. Opinions will be formed among farmers or their hinds as to your merit or demerit in your profession — your being or not being apt in all the mechanical operations belonging to cattle; therefore it behoves every young man, under such circumstances, to learn the way to hold a bullock by the nose and horns; to be able to cast him; how to take up his feet; how to head-rope him; and, likewise, how to milk.”

Now comes a part of the article that interested me very much because it has to do with my main historical research topic, bovine mastitis.  During my studies of the concept of bovine mastitis during the first half of the nineteenth entury, I found many reports about what we may call now the biomedical knowledge of the disease. This concept may be summarized as: mastitis is a swelling of the udder, with blood in the milk, followed in later stages by abcesses, induration and gangrene. The cause is high milk production after calving, exposure to cold and holding up the milk in the udder. Therapies are based on salt solutions and rubbing the udder with oils and campher (among many others).

The problem is that from these descriptions you can not decide on how mastitis was experienced in the practice of the cattle farm. But now Robert Read in his article in The Veterinarian lifted the veil a little bit when he explains why a young vet should be able to milk a cow.

“This latter circumstance [i.e. milking a cow] will be required in every case of udder-ill or mammitis, in order to ascertain the state of the secretion; for should you attempt to handle the teat and not draw any milk, or go to the wrong side of the cow, the milk-maid standing by, the laugh would be against you; and the words to the mistress would be, " A pretty sort of a cow-doctor: he didn't know the milking side of the cow."

Apparently, mastitis seems to have been so common at cattle farms that it was appropriate for vets to be able to milk the cow for a simple diagnostic test, i.e. ascertaining the state of the secretion.

1. Robert Read, On the pathology and general treatment of cattle. The Veterinarian, 16, 1843, 55-57