916 Obesity. 



lierited is very important. Animals also become phlegmatic 

 after castration (Ltithje) and then tend to put on fat. The 

 same is true for older animals. By diminishing muscular ac- 

 tivity anemia may favor the deposit of fat if it is not due to 

 an organic lesion or to deficient feeding. It has for this reason 

 become customary in many districts to promote the fattening 

 of the animals by periodical venesection. The diminution^ of 

 muscular activity finally becomes a favoring factor in producing 

 obesity in many broken-winded horses. 



In all these cases the obesity develops in consequence of an 

 absolute or relative hyperalimentation. As to whether aside from 

 this there also exists in animals a true constitutional obesity we 

 do not possess any observations based upon examinations of the 

 metabolism. This form of obesity might be expected to arise 

 from a slowing of metabolism because in such individuals the 

 weight unit protoplasm would transform less potential energy 

 into living force, primarily into heat (v. Noorden). As a matter 

 of fact, v. Bergmann recently actually demonstrated the slow- 

 ing of metabolism in persons affected with obesity. This diminu- 

 tion of the oxidizing function of the protoplasm may, according 

 to V. Noorden, have its cause in a peculiar constitution of the 

 protoplasm itself or it may be the consequence of abnormal 

 internal secretions, especially those of the thyroid gland which ■ 

 exerts a stimulating action upon oxidation, while its function 

 is regulated in its turn by other organs (pancreas, sexual glands, 

 hypophysis, adrenals), v. Noorden thus explains constitutional 

 obesity as a thyreogenic obesity. 



Anatomical Changes. The fat is present in very large pro- 

 portion, especially in the subcutaneous connective tissue whence 

 it may enter between the muscles and even between the muscle 

 fibers, also between the mediastinal folds, under the visceral 

 layer of the pericardium and possibly in the heart muscle, in 

 the omentum, the colon, in the region of the kidneys, etc. In 

 severe cases individual fibers of the muscles which are per- 

 meated with fat, for instance in the heart muscle, take on a 

 yellowish color owing to fatty degeneration. Of the internal 

 organs it is particularly the liver in which there is a great ac- 

 cumulation of fat. 



Symptoms. Obesity shows itself most strikingly in a 

 peculiar alteration in the shape of the body by which the out- 

 lines of the body are rounded out and the skin forms thick, 

 but soft and elastic folds. This change is most decided on the 

 trunk, especially on the abdomen, then on the thighs, the 

 shoulders and on the throat. The enlarg«^d belly sometimes 

 has an appearance as though the abdominal walls were forced 

 apart by fluid or a swelling, but the actual cause can easily 

 be determined by palpation and percussion and still better from 

 the other signs of obesity. The skin feels soft and elastic; 



