742 DISEASES AXIJ ABXOIIMALITIES OF THE YOUXG AXIMAL. 



Treatment. 



Preventive treatment must be directed to keeping the Ewes in a 

 healthy condition by proper feeding, and sheltering them from the 

 •weather if this be severe at lambing time. The Lambs should also be 

 kept from cold winds and wet, especially if they are of the more delicate 

 breeds. 



With regard to medical treatment, it is recommended to give a 

 purgative at the onset of the disease, and especially if there is any 

 reason to apprehend that the meconium is retained in the intestines. 

 Chloral hydrate or chlorodyne may be given in small and frequent doses, 

 alternated with sulphate of quinine. Friction may be applied to the 

 limbs, either without or with some stimulating liniment. 



CHAPTEE XIV. 



Cyanosis. 



At page 105, in describing the foetal circulation and the modifications 

 which occur in it at birth, it was mentioned that the lungs then become 

 the organs of respiration, and rapidly increase in capacity, while the 

 thorax enlarges in a commensurate degree ; the pulmonary artery also 

 dilates to admit the increased How of blood, and the ductus arteriosus 

 is obliterated to prevent mingling of the 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 occlu- 

 sion of the foramen ovale, though the latter opening not infrequently 

 remains intact in young animals. Eemarking upon the patency of the 

 foramen ovale, it was stated that, as a rule, this accident did not greatly 

 affect the circulation ; for when the heart contracts, the auricles are 

 isolated by the narrowing of the orifice and the elevation of a valve. 



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

 the foramen ovale, with perhaps defective auricular contraction, or an 

 abnormal disposition of the large bloodvessels at their origin, the arte- 

 rial 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 respiration, 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- 



' Vemant {Recueil de MM. Veterinaire, 1887, 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 sustain the weight of the body. 



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

 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 entire mass 

 was rather heavy. The foramen ovale was incompletely closed, so that the two auricles 

 could communicate with each other ; the opening was as large as a tive-franc piece, and 

 the auricular septum was extremely thin. 



