254 CLINICAL BACTERIOLOGY AND H.^MATOLOGY 



V. A LOWERED COUNT, OR LEUCOPENIA (under 5,000.) 

 This is not met with very frequently, and all the cases are in-, 

 eluded under IV. The chief are typhoid fever, pernicious 

 an&mia, chlorosis, influenza, malaria, and uncomplicated 

 tuberculosis. It occurs also in sepsis, and then indicates a 

 very bad prognosis. It is also found in starvation and mal- 

 nutrition. 



THE INVESTIGATION OF THE MORPHOLOGY OF 

 THE LEUCOCYTES AND RED CORPUSCLES 



To study the morphology of the leucocytes and red cor- 

 puscles it is necessary to prepare thin and even films of the 

 blood, and to submit them to appropriate methods of staining. 



METHOD OF PREPARING FILMS. I. WITH COVER-GLASSES. 



This is the best method for ordinary purposes, and, if the 

 instructions are carried out exactly, is a very easy one. 



Requisites. i. Perfectly clean cover-glasses. They should 

 be cleaned by one of the methods described on p. 33, and kept 

 in spirit. Immediately before they are required for use they 

 must be removed with a clean pair of forceps and rubbed well 

 with an old and soft handkerchief. 



I prefer No. 2 cover-glasses for this examination, as much 

 better films are made on them than on thin ones, which are 

 liable to bend under the powerful suction exerted by the 

 capillary attraction of the drop of blood when spread out thin. 



2. A needle for drawing blood. ' 



(3. A platinum loop having a diameter of about T V inc'h is 

 sometimes useful, especially to a beginner.) 



Rub the patient's ear or finger thoroughly with a piece of 

 lint or a towel, so as to make it hypersemic. Prick it, and wipe 

 away the first drop of blood. Then allow another drop to 

 exude; if necessary, you may squeeze a little. 



Take a cover-glass between the first finger and thumb of 

 the left hand, 'holding it by the opposite angles, and take 

 another between the first finger and thumb of the right hand, 

 holding it by adjacent angles (Fig. 51). 



Touch with the upper surface of the cover-glass in your 



