278 PURPUEA H.EMOKRHAGICA. 



the fitness of things and the relation of sequence and cause, to 

 attribute the occurrence of the disease to the natural effects of 

 such exhausting diseases as prolonged catarrh or influenza, 

 effects specially showing themselves in a deteriorated condition 

 of the fluid tissue, the blood, there are still cases Avhere we 

 encounter this disease in which it would appear, at least as far 

 as we can discover, that such deteriorating influences are not 

 and have not been in operation. Carefully and impartially 

 o-ivino- all supposed causes their duo consideration, and placing 

 them in connection with ascertained facts relating to the 

 disease, it would seem that all which minister to the produc- 

 tion of this peculiar condition are capable of being grouped as 

 causes indigenous and causes exogenous, the former probably 

 predominating. 



Seeing that purpura is to a great extent a disease of the 

 blood and capillary bloodvessels, we must look for the chief 

 cause of its production to those influences which operate in 

 disturbing or preventing the healthy formation of blood. And 

 as we are aware that the fluid tissue, blood, is the result of the 

 action of formative processes in connection with these com- 

 binations of phenomena we call primary and secondary 

 digestion, any impairment or disturbance in the details of 

 these will operate injuriously in the formation of this tissue, 

 which depends for its support and correct maintenance on the 

 regular and healthy action of these activities. It is only by 

 placing its causes first of all on such broad bases as these that 

 we can in some degree comprehend how, if it be true — of which 

 none entertain any doubt — that purpura, largely encountered 

 as a sequel of certain exhausting diseases, and peculiarly a 

 disease of debility, should also be met Avith under conditions 

 apparently the opposite. It is seen to follow exhaustive 

 catarrhal diseases where animal force and tissue-formative 

 power in every structure are largely impaired and at the 

 minimum, and when every organ and function are depressed by 

 the presence in the system of materials which, having served 

 their purpose, are now changed and efl'ctc, and ought to be 

 eliminated, but which from some functional disturbance are still 

 retained, and by their further disintegration and change render 

 the blood impure. It is also, although not so frequently, seen 

 where the animals are seemingly in perfect health, and their 



