34 PROTOZOAN PARASITISM 



It is well to have such fresh liquid material for 

 the determination of the presence of amoebae. It 

 is not by any means always possible to identify them 

 under these conditions. Frequent errors are made 

 in diagnosis by depending upon this preliminary part 

 of the examination. When amoebae are found it may 

 be possible to form a good idea as to their identity, 

 frequently it is impossible, always it is advisable to 

 simply recognize the presence of an amoeba and, if 

 no cysts are to be found, to wait until they may be 

 before making a positive identification. This does 

 not mean that it is necessary to wait for the cysts of 

 Eridmnoeba histolytica before a diagnosis of intes- 

 tinal amoebiasis is made. The character of the am- 

 oeba, its common red blood corpuscle inclusion, and 

 the clinical nature of the case, particularly the nature 

 of the stool, practically always allows a diagnosis of 

 amoebic dysentery at once and with positiveness. 



In chronic intestinal amoebiasis without dysentery 

 discovery of the cysts is practical and should be done 

 for a positive diagnosis. 



For better study of the nucleus and composition 

 of the body, food particles, etc., stained specimens 

 are necessary. The best stained preparations are to 

 be secured by the iron-haematoxylon methods about 

 as follows: 



1. Make thin spreads on slides (cover glass prep- 

 arations are less easily handled) and before they can 

 dry fix them in warm "Schaudinn's solution" (2 parts 

 saturated solution of bichloride of mercury to 1 part 



