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Proceedings of the Royal Society of Edinburgh. [Sess. 
I. — The Influence of an Excessive Meat Diet on the Osseous 
System. By Chalmers Watson, M.D. ( From the Physiological 
Laboratory of Edinburgh University.) Communicated by Professor 
Schafer, F.R.S. (With Four Plates.) 
(MS. received November 20, 1906. Read December 3, 1906.) 
In a communication given to this Society in December 1905, I described 
the clinical results obtained in an experimental investigation on the in- 
fluence of an excessive meat diet on the growth and nutrition of rats. 
It was there shown that the progeny of meat-fed rats are usually poorly 
developed and show a high mortality in early life. The present record 
comprises an account of the naked-eye and microscopic appearances 
observed in the osseous system of these meat-fed subjects. The material 
employed consisted in the young of mothers fed for some weeks or months 
prior to pregnancy, and during pregnancy and lactation, on a diet of ox- 
flesh, the animals, after weaning, being continued on the meat regime, an 
equal number of controls being taken from the young of rats fed on an 
exclusively bread-and-skim-milk diet. Both diets were given in unrestricted 
amount, and with the meat diet water was given ad libitum. Over a 
hundred meat-fed rats were utilised for the investigations, their ages 
ranging from one day to three months, the majority being under three 
weeks old at the time of death. A record was made of the naked-eye 
appearances of the skeleton, special attention being directed to the con- 
sistence as well as to the general appearance of the long bones, ribs, and 
flat bones. The tissues were fixed in formalin (5 per cent.), decalcified in 
weak nitric acid solution, and stained in the ordinary manner with hsema- 
toxylin and eosin. Sections were made through the anterior part of the 
cranium so as to demonstrate the conditions present in the frontal, malar, 
and maxillary bones, while, in the case of rats set. one day, three weeks, and 
two months respectively, sections were also made of the tibia, humerus, and 
ribs. Similarly prepared sections from control animals were, for comparison, 
mounted on the same slide. 
Macroscopic Appearances. 
The macroscopic conditions noted in the bones of the meat-fed rats vary 
according to the age of the animals, but show throughout, in a more or less 
marked degree, the same general characteristics. The most striking feature 
