1933 ANNUAL REPORT, 1932 



time to time is based purely upon practical observations, having little or no 

 experimental evidence to support it. Unquestionably a number of such obser- 

 vations have proven to be correct and have had a beneficial effect upon the 

 industry as a whole, but it is being found, especially with problems of disease, 

 that many erroneous ideas which have no scientific basis to warrant their adoption 

 as correct, are commonly accepted as true. 



Domestic animals and their diseases have been carefully studied for many 

 years, and with most of them the normal conditions found in healthy individuals 

 have been established, thus making it possible to compare the normal with the 

 pathological, and to arrive at conclusions which give a definite clue to the disease 

 under observation. The diseases which they are subject to, are also fairly well 

 established and any previously unknown disease arising among them is quickly 

 recognized as a new condition by the process of elimination. 



The reverse is the case with fur-bearing animals in captivity. The normal 

 condition to be expected in many of them is not known and the number and 

 variety of diseases to be looked for cannot even be surmised. In many of the fur- 

 bearers the symptoms are obscure and more difficult to observe on account of 

 the naturally suspicious nature of the animal. \'ery often the first indication 

 of disease may be that of finding the animal dead in the pen or kennel. Further- 

 more, the same disease may evidence itself in many different ways in a group 

 of individuals, in that very few will show the same definite symptoms. 



In view of the many difficulties presented in the treatment of fur-bearing 

 animals, preventive medicine is of the utmost importance, and research work 

 should be conducted with this aim in view. It also appears essential that a 

 thorough understanding of the normal conditions should be acquired before 

 attempting to interpret the pathological, and advantage should be taken whenever 

 possible of laboratory aids to diagnosis. 



During the year the blood morphology of foxes, mink and raccoon was 

 thoroughly studied. An extensive report on this work will be published and 

 made available for those desiring the information. 



Considerable importance is being placed on the blood morphology of man 

 and animals as an aid towards diagnosing certain classes of disease such as 

 anemia, acute infections, parasitic, nutritional and kidney disorders. Before 

 consideration can be given to any specific disease, a knowledge of the normal 

 blood morphology is essential in order to establish the deviation from normal. 



Since each species of animal varies in the number of blood cells to a given 

 volume of blood, it is necessary to establish the normal count for the various 

 blood elements. There appears to be a tendency to assume that the normal 

 blood counts established for the dog are approximateh^ the same for foxes. The 

 investigations carried out with foxes reveal very clearly that this assumption 

 is not correct and that the number of blood elements, staining reactions and 

 morphology are not similar to those of the dog. 



In the investigation of certain diseases at the Experimental Fur Farm, it 

 was considered essential that special attention be gi\'en to the blood morphology 

 of the animals being studied, namely, the fox, mink and raccoon. In order to 

 establish the normal blood counts and morphology of the blood of these animals, 

 over four hundred samples were taken from foxes, two hundred and fifty from 

 mink, and two hundred from raccoon. The blood was examined for haemoglobin, 

 red blood cells and white blood cells. Blood smears were examined for the 

 differentiation of the white blood cells into leukocyte, lymphocyte, monocyte, 

 eosinophil and basophil counts. 



