103 



4. Note any contents of the stomach 



(i) Remains of blood, 

 (ii) Crystals of various kinds, 

 (iii) Gregarincs, flagellates, bacteria, etc. 



5. Note that in focussing downwards one passes 

 through a double thickness of wall. Note that the 

 air tubes are focussed on the upper and lower surfaces 

 of the preparation, and the epithelium and crystals in 

 the middle. 



6. Trace several of the finer air tubes to their 

 apparent termination, and note that when they lose 

 their spiral lining they are continued as very fine 

 transparent tubules (air capillaries). Note that at the 

 point of breaking up, one can generally make out 

 large stellate cells (tracheal cells) (Fig. 39). 



7. Observe in some preparations, large oval cells 

 of brownish colour lying upon the outer surface of the 

 stomach. Note that they are rather opaque, and 

 contain a certain amount of diffuse yellowish pigment. 

 They are so-called pericardial cells (Fig. 39). 



8. Observe, in most preparations, one or more 

 large clear cells with a small nucleus, and filled with 

 oil globules (cells of the fat body) (Fig. 39). These 

 lie upon the stomach and, in common with the last- 

 named cells, are accidental in this situation. 



THE EXAMINATION OF THE MiD-GuT FOR THE 



ZYGOTE OR OOCYST STAGE OF THE 



MALARIAL PARASITE 



(The examination of the stomach Hood for flagellating and the 

 motile or vermicule forms is deferred to a later Chapter). 



Obtain a number of Anophelines (not M. rossi) 

 from some native hut, or better, those specially fed. 

 Keep these alive for two or three days until no blood 



