Coui'se. Diagnosis. 97 



abdomen, on the lower chest and on the extremities, nntil tlie 

 animals are ntterly unable to work and have to be killed. 



Course. Months, perhaps years, elapse until the disturb- 

 ances in respiration and circulation point, even at rest, to 

 material tissue changes. (Holterbach saw severe shortness of 

 breath appear forty days after a convulsive coug'li; it is not 

 clear, however, whether this case was one of chronic emphysema 

 of the lungs.) The course is much influenced by the work 

 required of the animals, since hard work leads to respiratory 

 and circulatory disturbances and to a more rapid progress of 

 the pulmonary changes, to the development of complications, 

 particularly of obstinate bronchial catarrh and these of course 

 materially contribute to a further deterioration of the condition 

 of the animals. This may particularly be observed in horses 

 which, because of their lessened ability for work are sold to 

 poorer proprietors, where they have to work still harder and 

 at the same time receive poorer food, for which reasons they 

 often succumb rapidly. Recovery or a permanent stationary 

 condition of the affection appears excluded on account of its 

 very nature, because the existing pulmonary bloating will pro- 

 duce respiratory difficulties and these will of necessity further 

 increase the morbid condition. Transitory, and even marked 

 and rapid improvement occurs, but this is almost without ex- 

 ception due to improvement in the complicating bronchial 

 catarrh. If this occurs, a decrease of the pulmonary dilatation 

 is at once demonstrable. A sudden deterioration may occur 

 in consequence of the development of an interstitial emphysema. 



Diagnosis. In a more advanced stage the disease can 

 easily be diagnosticated, if the signs of enlargement of the 

 lungs, of an increased air content, and a decrease of elasticity 

 are present. Early in the course of the disease it cannot be 

 diagnosticated by the aid of physical methods, because the 

 changes in the pulmonary tissue are of a minor degree ; it may, 

 however, be suspected if dyspnea of a more or less pronounced 

 character is present and if reliable data reveal a preceding- 

 pulmonary aifection, while careful examination of the thoracic 

 organs for other changes is negative. 



Temporary relief from dyspnea is often brought about by horse dealers by 

 the internal administration of leaves, roots or seeds of plants containing atropine 

 (Atropa belladonna, Datura stramonium, Hyoseyamus niger). Eaitsits ' experiments 

 made in the Budapest clinic have shown that these plants do not merely reduce 

 the frequency of respiration, but also abolish the double period and the forced 

 character of the respirations, so that it may appear perfectly normal, even in 

 advanced cases. The effect is produced within fifteen minutes and lasts a whole 

 day. After the effect has vanished the dyspnea becomes more intense than previously. 

 During the first hours after the administration of the above-mentioned plants the 

 buccal mucosa is very dry (to mask this it is usually rubbed with fat). One also 

 observes dilatation of the pupils which do not respond to light (sometimes also 

 visual disturbances), and a considerable increase of the pulse rate. Subcutaneous 

 injections of atropine (0.03-0.05 gm.) have the same effect; this, however, comes 

 on within a few minutes and lasts only for one to three hours (see Fig. 10), 



Vol. 2-7. 



