CYANOSIS. 765 



eratecl to prevent the mingling of arterial and venous blood. It was also 

 stated that the ductus venosus likewise aids in the isolation of the two 

 kinds of blood by becoming atrophied, as does also the occlusion of the 

 foramen ovale, though the latter opening not infrequently remains intact 

 in young animals. Remarking upon the patency of the foramen ovale, 

 it was said that, as a rule, this accident did not greatly affect the circula- 

 tion ; for when the heart contracts, the auricles are isolated by the nar- 

 rowing of the orifice and the elevation of the valve. 



Cases occur, nevertheless, in which, either from the persistence of the 

 foramen ovale, with perhaps defective auricular contraction, or an abnor- 

 mal disposition of the large blood-vessels at their origin, the arterial and 

 venous blood is mixed, and we have the condition known as cyanosis or 

 the " blue disease." Then there is a deep-blue or violet coloration of the 

 visible mucous membranes, more or less debility and difficulty in respira- 

 tion, especially during exertion, coldness of the limbs and surface of the 

 body, and a great predisposition to haemorrhage. 



Cyanosis may occur in otherwise well-developed individuals, and be 

 due to a congenital adhesion between the lungs and pleura or pericar- 

 dium ; it is also a symptom of asphyxia, and is sometimes witnessed in 

 colic in the horse, complicated with meteorismus ; it likewise accompanies 

 certain forms of poisoning. 



When due to the first-named causes, this condition is manifested during, 

 or immediately after, birth ; it is only in rare instances that it is developed 

 at a later period. It is needless to mention that such a conformation is 

 beyond remedy, though animals so affected will often live for a long time; 

 Zundel has seen a horse seven years old which was in this condition. 



Vernant {Reciceil de Med. Veterinaire, 1877, p. 592) was called to see a calf which had 

 been born the previous evening, and with such ease that it was found behind the Cow, 

 no one being present at its birth. It was viable, in very good condition, fat, and so well 

 developed that it looked as if fifteen days old. But it could not stand, and lay constantly 

 in the sternal position, refusing to suck. ' The symptoms it presented were markedly those 

 of asphyxia : the tongue was half protruded from the mouth, the eyes prominent, the 

 respiration plaintive and hurried, and the flanks very agitated. When raised it could 

 not stand ; its limbs were constantly and convulsively moved, and were unable to sus- 

 tain the weight of the body. 



The animal was bled at the tail, but this afforded no relief, and in forty-eight hours 

 after birth it died. The lungs were then found to be collapsed, and looked very con- 

 gested. The anterior extremities of the lobules floated well in water, but the mass of 

 the lungs was rather heavy. 



The foramen ovale was incompletely closed, so that the two auricles could communi- 

 cate with each other ; the opening was as large as a five-franc piece, and the auricular 

 septum was extremely thin. 



Another congenital malformation to which we have not devoted a 

 special chapter, is ".tongue-tie " in young animals, and particularly 

 calves. 



Tyvaert {Annales de Med. Veterinaire, June, 1877) has observed this 

 condition on six occasions in calves. It is similar to tongue-tie in chil- 

 dren and certain birds, and is characterized by the fraenum linguae being 

 too narrow from above to below, and too much prolonged forward — some- 

 times extending to the root of the incisor teeth. This anomaly greatly 

 hinders the prehension of food and swallowing of fluids ; the calf, if 

 drinking out of a bucket, vainly plunges its face into the fluid as far as 

 the eyes. The teat is seized with difficulty, and the tongue is so limited 

 in its movements that it cannot be protruded to lick the nostrils, as is the 



