210 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



estimation of haemoglobin. The normal numbers in health are 

 taken to be 5,000^000 red corpuscles per cubic millimetre in adult 

 males, and 4,500,000 in adult females. As a matter of fact, these 

 figures are very frequently exceeded. In newly born children the 

 number is about 5,250,000, and in older children about 5,000,000 

 in both sexes. Any decided fall from these figures indicates 

 anaemia. 



The number of red corpuscles per cubic millimetre is increased in 

 any condition in which the total volume of the blood is diminished 

 by loss of the fluid portion of the blood — e.g., in severe diarrhoea. 

 This fact is occasionally of diagnostic value. For example, the 

 red corpuscles appear more numerous in typhoid fever, especially 

 in the earlier stages of the disease : the figure may exceed 

 6,000,000. Later in the disease a fall takes place, though it is 

 never very great, and if in a continued fever the red corpuscles 

 are less than 3,000,000, the diagnosis of typhoid is unlikely. 

 This is very different to what happens in malaria, where there 

 is great and progressive destruction of the red cells, and a figure 

 below 2,000,000 very common. This may be of value in diagnosis 

 in cases where the parasites cannot be found, and Widal's reaction 

 fails or cannot be tried. 



On the other hand, care must be taken not to mistake this 

 concentration of the blood for an actual improvement — e.g., if in a 

 case of septic infection, puerperal fever, etc., the number of reds 

 shows a sudden rise, the question of whether the blood has been 

 concentrated by profuse diarrhoea, sweating, etc., must be inquired 

 into before the findings raise hope of a speedy recovery. Mistrust 

 all results showing an increase 9f more than 100,000 red corpuscles 

 a day. Such rapid improvement does occur, but is unusual. 



The red corpuscles are also very numerous (up to 10,000,000) 

 in congenital cardiac disease with cyanosis, and as an obscure 

 primary condition, and in venous stasis from mitral disease or 

 any other cause. 



A decrease of the number of red cells indicates anaemia, and the 

 numbers may be taken as a criterion of the degree of anaemia 

 present. But this is not so accurate a test as the percentage of 

 haemoglobin, since, it is the quantity of this substance that is of 

 importance, the number of parcels into which it is divided being 

 of comparatively little moment. The grade of anaemia, therefore, 

 should be expressed by the percentage of haemoglobin, not by the 

 number of corpuscles. This is of some importance, since in the 



