96 PARASITIC AMOEBAE OF MAN. 



with either wet or dry-fixed preparations, when 

 Wright's stain is used, but if iron hsematoxylin be 

 used the wet-fixed preparations give the best results 

 as regards the structure of the nucleus. Some author- 

 ities have claimed that unless the preparations are 

 wet-fixed no deductions can be drawn regarding the 

 structure of the nucleus in stained preparations, but 

 with this statement I must entirely disagree. It 

 makes but little difference whether the specimens be 

 fixed wet or dry, when Wright's stain or any other 

 modification of the Romano wsky stain is used, although 

 the best results are obtained in wet-fixed preparations. 

 I cannot but believe that many of the appearances 

 presented in wet-fixed preparations are just as arti- 

 ficial as any that may be observed in the dry-fixed 

 preparations, and there is considerable reason for 

 concluding that both wet- and dry-fixed preparations 

 should be used in the study of this class of protozoa. 

 When Wright's stain is used Entamceba coli 

 presents three distinct portions, the ectoplasm, the 

 endoplasm and the nucleus. However, it should be 

 remembered that these three divisions are not always 

 visible, as not infrequently the entire amoeba stains 

 uniformly throughout, with the exception of the nu- 

 cleus. The period of development apparently makes 

 a great difference in the facility with which the or- 

 ganism takes the stain, as well as with the reaction 



