636 APPENDIX. 



cases, and in cases of mixed malarial infection occur- 

 ring in malarial regions, a careful blood examination 

 enables a positive diagnosis to be made in a large 

 majority. 



Technique of Blood Examinations for Malaria. The 

 finding of the parasite should not prevent us from 

 seeking farther in doubtful cases by means of the 

 Widal reaction and blood cultures for other infections 

 which may exist along with the malaria. 



The parasites require a proper technique and a 

 certain experience for their recognition. The fresh 

 blood, when it can be obtained, should be examined, 

 but if no bodies be found, stained preparations should 

 always be later searched through; the drops may be 

 taken either from the tip of the finger or from the 

 lobe of the ear. It is important to have a perfectly 

 clean cover-glass and slide, and to cleanse the skin 

 thoroughly and to wipe it dry, so as to avoid dirt and 

 perspiration. A very small drop should be taken, and 

 care must be exercised that the cover-slips, when pressed 

 against the blood-drop, do not touch the skin. The 

 drop should be so small that the corpuscles are spread 

 out in a uniform layer and are not in rolls when the 

 cover-glass is laid upon the slide, for the intracorpus- 

 cular form cannot be well seen unless the blood-disk 

 presents the flattened surface. For making permanent 

 preparations the blood is collected upon cover-glasses 

 in very thin films, which should be instantly dried. 

 The blood-cells are fixed by immersion in equal parts 

 of alcohol (95 per cent.) and ether for fifteen minutes, 

 or by exposing for five minutes over a wide-mouthed 

 bottle containing 25 per cent, solution of formalin, or 

 by heating to 120 C. for ten minutes. Ewing advises 



