XATURE. 277 



morbid conditions of tissue-elements are not invariably of one 

 and the same clraracter, and tliat these ditferences of abnor- 

 mality originate from different causes, manifest themselves 

 in somewhat different ways, and in their management demand 

 somewhat different treatment. 



In one form we have certainly an altered condition of the 

 blood itself as the most prominent feature of the disturbance, 

 but even this alteration may not be invariably of the same 

 character. There is evidence that it presents itself for our 

 consideration in at least two forms : 1. In what we may term 

 the aqueous condition, where an excess of water is present 

 and a deticiency of albumen and fibrine factors. 2. A condition 

 in which the colloids of the blood, the albumen and fibrine- 

 producing materials, are in undue solution, and probably also 

 the formed materials, the blood-globules. While in many, if 

 not in all, there is another, a third, abnormal condition which 

 must be taken into consideration — viz., the changes which the 

 capillaries have undergone, most probably textural degenera- 

 tion, by which the blood-elements are allowed to transude and 

 permeate the surrounding tissues. 



It is deserving of remark that, troublesome and serious- 

 looking as the cutaneous patchy elevations resulting from the 

 capillary extravasation are, they cannot be taken as true or 

 good indices of the amount of danger attendant on the attack; 

 the greatest danger in connection with which is the chance of 

 blood-extravasation mto the intimate texture of, or in connec- 

 tion with, organs and structures essential to life. 



Although the accompanying fever as a rule is not great, 

 weakness and prostration are marked features. The wealoicss 

 we can understand, as well as the marasmus, when we observe 

 the imperfectly carried on assimilatory functions and great 

 tissue- waste ; these indicated by the altered state of the 

 nutritive fluid, the blood, and the excreted fluid, the urine. 

 The former of these is to a considerable extent rendered unfit 

 for healthy nutrition from both physical and chemical changes ; 

 the latter becomes increased in density from excess of^tissue- 

 elements, the result of increased tissue-change, 



h. Causmtion. — Although it may seem a perfectly rational 

 way of accounting for the phenomena characteristic of purpura 

 ha^morrhagica, and m no way doing violence to our ideas of 



