64 



DISEASES OF THE DIGESTIVE APPARATUS. 



1. The theory of imitation is especially defended by Spinola. 

 According to him, inaction and weariness are the starting-point 

 of the defect. The principal arguments which he advances in 

 favor of his opinion are the following : At the beginning the 

 disease exists in one animal ; later it is generally observed only 

 among certain groups of animals of the same sheepfold ; its course 

 has often been stopped by a strict separation, through isolation of 

 the " wool-eaters (Spinola, Burmeister) ; finally, we may see it 

 appear before the winter stalling, that is to say, before the time 

 when ordinarily diseases of nutrition occur. 



2. The disease has long been looked upon as being the result of 

 a disturbance of nutrition^ produced by food that is either insuffi- 

 cient or is deficient in its chemical composition. Among modern 

 -authors, Lemke especially has reinstated this theory by basing it 

 upon experiences the results of which permit us to exclude the 

 influence of imitation. The disease is particularly noticed in 

 winter, at the time when the food is insufficient or is composed too 

 exclusively of potatoes and malt residues, substances which are 

 poor in nitrogen, or when dry fodder is wanting, etc. In spring 

 it disappears under the influence of a change of diet. In lambs 

 it happens, ordinarily, when the milk-giving ewes are fed too 

 sparingly, and when there is a deficiency of milk, or if its chemical 

 composition is poor. In one sheepfold where the lambs, not 

 finding a sufficient quantity of mother's milk, had eaten wool. 

 May saw the disease disappear when the young animals had been 

 supplied with cow's milk. The trouble has also been charged to 

 damp, turfy, and acid pastures, as well as to excess or lack of sea- 

 salt (Haubner-Siedamgrotzky). 



Frequency. Mallophagia is especially found among improved 

 races, particularly among merinos, and, as stated, at the time the 

 animals are fed in the sheepfold — that is to say, during the 

 winter. Often the trouble appears suddenly, eight or fifteen days 

 after the animals are placed on winter diet, and disappears of its 

 own accord as soon as the sheep go to pasture. 



Symptoms. Young lambs from two to six weeks old begin to 

 nibble their mothers' wool, preferably that of the limbs, abdomen, 

 and tail. At first this act seems an amusement, a simple caprice, 

 but the habit soon becomes a craving, and the lambs eat indis- 

 criminately the wool of all sheep. Ordinarily they preserve a 

 :healthy appearance, but at times they swallow considerable quan- 



