450 MATERIA MEDIC A AND THERAPEUTICS. 



cause. Uric acid is certainly in excess in gout. In calculous 

 subjects there is apparently some obscure tendency to distur- 

 bance of the reaction of the blood, referable to derangement 

 of primary and secondary digestion. Sugar is in excess in 

 diabetes, probably from disordered supply ; urea is in excess in 

 Bright' s disease, from defective excretion. The white corpus- 

 cles are liable to abnormal increase, as in leukaemia, but it is 

 still doubtful whether these are instances of primary disease of 

 the blood. 



The diseases of the red corpuscles are certainly few and 

 imperfectly known; practically they may be represented as 

 deficiency, and deoxydation or reduction of haemoglobin. De- 

 ficiency of haemoglobin, whether traceable to want of blood as a 

 whole, to poverty of the blood in red corpuscles, or to deficiency 

 of the individual corpuscles in haemoglobin, reduces the oxy- 

 genating value of the vital fluid. All the bodily functions become 

 feeble : the patient is weak, dull, sleepy, and suffers from every 

 possible functional derangement, especially shortness of breath. 



Reduction of haemoglobin, or, more correctly, of oxyhaemo- 

 globin, is a result of the admission to the blood, in poisonous 

 quantities, of certain substances which we have already 

 mentioned, such as Phosphorus, Arsenic, or Turpentine in 

 poisonous doses. Carbonic Oxide enters into combination with 

 the haemoglobin, whilst the oxygen is expelled from the 

 corpuscles. Hydrocyanic Acid unites partly with oxyhaemo- 

 globin, partly with reduced haemoglobin. Other bodies, such 

 as Sulphuretted Hydrogen, seize upon and combine with the 

 oxygen, leaving the reduced haemoglobin to be dissolved out of 

 the corpuscles and diffused through the blood. Either of these 

 conditions is highly dangerous, the new haemoglobin compound 

 in the first case being with difficulty replaced by oxyhaemoglobin ; 

 whilst the reduction and solution in the second case are incom- 

 patible with life if they have occurred to any extent. 



IV. NATURAL RECOVERY. 



The quantity and functional value of the liquor sanguinis, 

 being but the balance between the income and output of the 

 body, readily return to the normal after disturbance. The 

 same is true of the corpuscles. As long as the disorders 

 of the red corpuscles are of a purely quantitative kind, 

 the restoration of the normal conditions is followed by 

 a return of the blood-elements to their proper constitution. 

 The natural means of recovery are to be found in the 

 shortness of breath and debility which accompanies anaemia, 

 and which compel the patient to spare the blood every 

 possible source of waste; at the same time the increased 



