DIFFERENTIAL DIAGNOSIS OF THE DYSENTERIES 215 



from such sources should be critically reviewed. This work should 

 not be delegated to a young hospital interne or a clinical clerk. 

 It should be done by the clinical man of the group, and such work 

 as he may require to be done by others should be carefully checked 

 by him. This care and thoroughness in the clinical observations 

 should be continued throughout the studies. 



If the laboratory work on the subjects is well done, it is highly 

 probable that it will be discovered by this time that a considerable 

 number of candidates will be unsuitable for further study, for 

 no matter how promising their crop of parasites and their intes- 

 tinal symptoms may appear at the outset, many inevitably will find 

 their place in the group of diseases in which the basic pathology 

 is clearly out of the field under investigation, or in which it 

 is generally conceded that intestinal symptoms are secondary 

 to a disease of extra-intestinal nature. This process of elim- 

 ination is one of the most important and, I may add, one of 

 the most frequently neglected features in studies on these prob- 

 lems. 



Apart from the study of the bowel discharges, which I shall 

 discuss separately, I should regard the following as about the 

 minimum amount of laboratory investigation each subject should 

 receive : 



Tlic Blood. The study of the blood should include careful total 

 erythrocyte, leucocyte and differential counts, the study of w^ell- 

 stained films, hemoglobin estimation, and the color index. It is not 

 an indifferent matter how this is done. The literature bears evi- 

 dence of the lack of harmony there has been in the methods em- 

 ployed in the study of the blood. IMuch of the work on blood 

 counts and hemoglobin estimations in connection with the maladies 

 we have under discussion has been done by such varying and 

 haphazard methods as to leave us in a position of extreme uncer- 

 tainty as to the facts. This is shown in the paper of Fischer (1919) 

 who made a study of the blood in amoebic dysentery, and that of 

 Lampe (1923) who made similar observations in bacillary dysen- 

 tery. 



In order that comparison may be made with the pictures shown 

 in the primary anemias and sprue, blood studies are needed in the 

 diarrheas of various types (including "flagellate diarrheas"). The 

 counts should be made during non-diarrheal periods as well as 

 during exacerbations. This should yield information regarding the 



