IOI 



To PREPARE THE MiD-GuT FOR EXAMINATION 



1. Cut (by pressing with the needle) across the 

 intestine and malpighian tubes just below the termi- 

 nation of the saccular mid-gut. This will separate 

 the mid-gut from the rest of the viscera. 



2. Remove everything from the slide but the 

 mid-gut. Remove excess of fluid, and see that no 

 ova or extraneous matters are left upon the slide. 

 Add a small drop of clean salt solution, and place a 

 thin coverglass upon the preparation. The mid-gut 

 will flatten out considerably. Remove with filter 

 paper applied to the edge of the coverglass any excess 

 of fluid. Examine under one-third inch objective and 

 afterwards under one-twelfth. 



If the mid-gut has been removed in toto, and the 

 preparation not too much compressed, the following 

 appearances are seen : 



1. The narrow anterior portion of the mid-gut 

 with the calyx-like proventriculus at its free end. 



2. If a portion of the extremely thin membrane 

 of the true oesophagus or its diverticula be included 

 in the preparation, it will probably be seen to exhibit 

 peculiar markings, due probably to muscular fibres 

 in the membrane, but resembling rather closely 

 sporozoits. It is essential that this structure should 

 be recognised when seen, and that the resemblance 

 of its markings to sporozoits should not lead the 

 beginner astray (Fig. 40). 



3. The expanded posterior portion of the mid- 

 gut. This body forms the main mass of the prepara- 

 tion, and is all important in relation to malarial studies. 



The following appearances are seen in a good 

 preparation : 



I. Well-defined tubes with spiral lining (air 



