103 
4- Note any contents of the stomach— 
(i) Remains of blood. 
(ii) Crystals of various kinds. 
(iii) Gregarines, 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 blood for flagellating and the 
motile or vermicide 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 
