DIFFERENTIAL DIAGNOSIS OF THE DYSENTERIES 205 



tion of criteria that shall make it clear to the clinician when the 

 administration of serum is essential or, in advanced cases, when 

 it is likely to be of avail. I need not go into the old controversy 

 over the limitations of serum therapy. It is sufficient to say that 

 the prevailing opinion is that serum is not effective if given later 

 than three to five days after the onset of the attack. I think this is 

 true in a large proportion of instances, but I also am growing to 

 believe that many cases are benefited by serum given even later. 

 Moreover, I think a more detailed knowledge of the finer charac- 

 ters of the bowel exudate in these late cases, and also in the very 

 early cases, is likely to give us something to work on. 



All this requires a more definite knowledge of the significance 

 of the varying proportions that the different cells in the dysentery 

 exudate bear to each other. In a frank bacillary dysentery, the 

 polymorphonuclear neutrophiles usually greatly outnumber the 

 other types of cells present. Yet, there are frequent instances in 

 which epithelial and endothelial cells dominate the picture and the 

 neutrophiles, although numerous, furnish a much lower propor- 

 tion. I have not been able to draw any definite conclusions regard- 

 ing this. Bahr (1918) regards the persistence of the endothelial 

 macrophages in the exudate as the case progresses as indicating 

 active process of repair. Occasionally, though, one encounters 

 a case that continuously produces a high proportion of macro- 

 phages, and at the same time runs a long and severe course. Study 

 of this point is of real importance. 



IMononuclear cells of a distinctive type — not lymphocytes — fre- 

 quently are seen in bowel exudates. By some they are spoken of 

 as plasma cells, by others as "irritation cells," although their rela- 

 tion to the so-called Turck's cell is not made clear, and hematolo- 

 gists tend to regard Turck's cell and the plasma cell as representing 

 two different types. For myself, I am in doubt as to what they 

 are. I do know, however, that in certain instances, such as I have 

 described (1924/7), they dominate the picture. I am convinced 

 they are of great importance in certain conditions. 



Eosinophile leucocytes often make their appearance in consider- 

 able numbers, both in amoebic and in bacillary dysentery. At times 

 it is to be suspected that their presence is associated with serum 

 reactions or with helminthiasis. In other instances, there seems no 

 explanation for their presence in such large numbers. Their rela- 

 tion to intestinal allergy, or atopy, will be discussed elsewhere. 



