284 PURPURA H.EMORRHAGICA. 



Visually after the diagnostic symptoms have been fully matured, 

 and in severe cases on the occasion of a remission of symptoms 

 and their renewed appearance, local blood-extravasations, 

 either extensive or more restricted, occur in connection with 

 internal structures and organs essential to life ; such internal 

 extravasations are very serious, and are characterized by 

 sudden and fatal collapse, or by the development of symptoms 

 indicative of disturbance or change of those organs in con- 

 nection with which the blood-extravasation has occurred. 



Course and Termination. — When purpura hiBmorrhagica is 

 fully established, and the diagnostic symptoms indicative of 

 the peculiar blood-changes have declared themselves, if the 

 diseased condition does not rapidly terminate in a fatal issue 

 its course is generally protracted. 



During the continuance of the disease we cannot say that 

 any definite, well ascertained, and clearly marked out course 

 belongs to it. The character of the symptoms, taken in 

 entirety, may be regarded as decidedly intermittent. This 

 very character is often the cause of much disappointment, 

 the animal being, on the subsidence of the more severe and 

 diagnostic symptoms, apparently on the way to convalescence; 

 but when seen again, all have reappeared with greater severity, 

 and without any cause for this accession, as far as we are able 

 to discover. The existence of unhealthy sores, resulting from 

 death and removal of the skin over certain cutaneous swell- 

 ings, seem to exercise an evil influence and to retard con- 

 valescence ; or probably we ought rather to say that the 

 existence of these unhealthy sores is more surely indicative of 

 a greater deterioration of animal health and vigour than 

 regard them individually as capable of retarding recovery. 



When purpura htemorrhagica does not kill by blood-eft'u- 

 sion and tissue-change of organs essential to life, the subjects 

 affected usually recover and ultimately regain their previous 

 condition ; there are, however, exceptions where, although not 

 fatal, the lesions occurring as sequclte of the disease per- 

 manently invalid and debilitate the animal, and some, such 

 as those of a cardiac nature, may prove fatal years after the 

 disappearance of the causes from which these changes have 

 originated. The ordinary form which the disease assumes, or 

 rather, we should say, the conditions in which it terminates when 



