1110 General Diuiiiiutioii in the Tonus of the Small Arteries. 



which corresponded to a dilated Arteria ischiadica. Querippel described 

 a dilatation of the crural arterj% Straube one of the Arteria digitorum 

 communis volaris, Blase one of the Arteria pharyngea in a horse 15 

 years old ; in the last case the symptoms consisted in edema and ulcera- 

 tions on the head and neck, swelling of the tongue and gums, salivation, 

 and the usual signs of pharyngitis ; the aneurism eventually burst into 

 the pharj-ngeal cavity. Vogel observed a dilatation of the facial artery 

 in a cow, Mou(iuet one in the cervical artery in a horse, Ravenel one 

 in the brachial artery in a hen. Nocard found in a young dog an 

 aneurism of the aorta and at the same time one of the pulmonary artery. 

 Mouquet found in a horse a dilatation of the pulmonary artery ; 

 Chardin in a horse a dilatation of the hepatic artery, which weighed 

 14 kg. (the horse had frequently stood still on trotting and disliked to 

 gallop), Dupas found varicose dilatations in the territory of the mesen- 

 teric veins, and Frohner in a horse a dilatation of the external thoracic 

 •vein. 



General diminution in the tonus of the small arteries. (General vas- 

 cular paralysis). A reduction in the tonus of all small arteries may be 

 produced by certain chemical substances, like amyl nitrite, alcohol, 

 chloral hydrate, chloroform, if they have been introduced into the organ- 

 ism in considerable amounts. Romberg, Bruhns, Pilssler and Roily dem- 

 onstrated in their experiments a similar action on the part of the toxins 

 of various infectious substances. From a general relaxation of the 

 arteries it necessarily results that the abdominal vessels, the innervation 

 of which is derived from the N. splanchnicus, and which especially in 

 herbivora form a very wide system of blood vessels, receive a very con- 

 siderable portion of the total blood quantity, so that the amount of blood 

 in the other organs is diminished. The diminutix)n in blood pressure 

 and the slowing of the blood circulation cause an acceleration of the 

 contractions of the heart, the pulse becoming feeble and empty, because 

 the retarded circulation and the overdistension with blood of the abdom- 

 inal organs have produced a deficient filling of the heart. Cyanosis 

 develops in addition, although the vessels of the mucous membranes and 

 the other veins are not filled unduly, because the backflow of the venous 

 blood toward the heart is not interfered with ; in severe cases the bluish 

 discolored mucous membranes are pale or livid. The anemia of the brain 

 gives rise to disturbances in consciousness and in respiration, and at 

 times the inner temperature falls below normal. Finally the slow cur- 

 rent in the blood vessels reduces the functioning power of the heart, 

 and heart weakness is added to the original circulatory disturbances. 

 Severe general atony of the arteries causes death in a short time. 



In fatal cases of colicky diseases in horses (especially after rupture 

 of stomach or intestine ) , also in the course of general infectious diseases 

 the authors have observed this clinical picture repeatedly. It probably 

 occurs not quite rarely, either alone or associated with the symptoms 

 of acute myocarditis. 



The trouble is differentiated from cardiac weakness only by the fact 

 that the veins are never filled strongly. 



If atony is not yet complete its removal may be attempted by vaso- 

 contracting remedies (camphor, caffeine, barium chloride, eserine, adren- 

 alin, suprarin or by intravenous infusions of a physiological salt solu- 

 tion with adrenalin or suprarenin, while vaso-dilating remedies (alco- 

 hol, ether) must be avoided. — (Piissler & Roily, Miinch. Med. Woch. 

 1902, 1737). 



