DISEASES OF THE BLOOD. 143 



aud tlie animal lies somewhat persistently. Here, also, 

 the vesicles rupture. The serous fluid, when exposed to 

 the air, dries and forms a yellowish layer of material 

 which readily pulverises. The last stage is marked by 

 disappearance of acute febrile symptoms, increase in 

 quantity of milk, which has been much reduced, oblitera- 

 tion of the exposed surfaces by development of new epi- 

 thelium and cessation of lameness. Sometimes the disease 

 assumes a more virulent type, dependent upon defective 

 hygienic arrangements, or upon obscure climatic influences. 

 Then the nasal, laryngeal, conjunctival, bronchial, gastric, 

 and duodenal mucous membranes present vesicao ; the anus 

 and vulva are similarly affected ; there is a tendency to 

 sloughing of parts in connection with the vesicae, and 

 extensive removals of epithelium. In such cases young 

 animals will die before the eruptive stage^ the only lesions 

 manifested on post-mortem examination beinff>??5^^etion 

 of the lungs j while older animals suffer MWm severe /^^ 

 irritative fever, rapidly lose flesh, and are Maol^' fo.jgiin-^'^^^ '/^ , 

 cumb from exhaustion. In these cases, tolL^^ere ^^ii^j> 

 marked liability to the various comj)licatim^^-0^p^3 "* T ^ 

 disorder. In whatever part they occur the vesicseSi^ii/tfJ^J'Ii^. 

 associated with acute inflammatory action of deeper tissue^T" 

 such as glossitis leading to extensive sloughing or indura- 

 tion, mammitis, and inflammation of the structures of the 

 foot, with production of sinuous ulcers and a tendency to 

 sloughing of the claws, open joint, and casting of the hoofs. 



Mammitis may result either from extension of inflam- 

 mation along the lining membrane of the ducts of the milk 

 glands, or from a blocking up of the openings of the ducts 

 leading to over-distension with milk. Abscesses, indura- 

 tion, and blind teats supervene upon these cases, also the 

 frequent irritation in milking a cow with sore teats may 

 render her permanently vicious. 



When the alimentary mucous membrane is involved 

 in the disease diarrhoea replaces the constipation which 

 is generally present. CEdematous swellings, too, some- 

 times are manifested. In each of these latter com- 

 plications there is extreme debility. Under ordinary 



