28o 



The figures are by no means always as high 

 as this, but, as we have already said (p. 41), 

 we consider a value above fifteen per cent, as 

 diagnostic of malaria. The higher values are 

 appreciated at once by an inspection of the 

 slide where the large mononuclears seem to occur 

 in every field, and may be pigmented. For the 

 low values a careful count is required. 



An increase in the large mononuclears has 

 been found in one case of human trypanosomiasis. 

 This has not, so far, been confirmed, but if it is, it 

 can but slightly effect the value of the counts in 

 malaria as a diagnostic means, for the clinical fea- 

 tures of trypanosomiasis, so far as known, are 

 extremely characteristic, and the chance of an 

 European being infected with the disease does not 

 appear to be great, the two known cases having 

 occurred in tropical Africa. Further, together 

 with the increase of the mononuclears in malaria 

 there are, if thorough search is" made, also pig- 

 mented leucocytes to be found. The relative 

 count of malaria is of great assistance in at least 

 two conditions, (i) in those cases where quinine 

 has been taken, (2) where consequently the diag- 

 nosis is uncertain and the question of typhoid 

 fever arises. As we shall now see, the relative 

 count in typhoid is quite different from that of 

 malaria. 



