78 
PRINCIPLES OF BACTERIOLOGY 
disease”—disease which follows the administration of 
various serums. In many cases the serum should be given 
in very small doses before the full amount given in order 
to avoid the possibility of anaphylaxis. 
Besredka, of Paris Pasteur Institute, developed a 
more perfect technic of “desensitization,” that is, avoid¬ 
ing the anaphylaxis, by testing the sensitiveness of a 
patient by first introducing minute quantities of the 
serum subcutaneously. 
Diagnosis of Hay Fever and Asthma hy Anaphylactic 
Reaction .—Through the work of Dunbar, Cooke, Vander 
Veer, and particularly of Walker, it is now possible to 
establish the particular pollen causing in a given patient 
hay fever or the particular protein (either food, bac¬ 
teria, or animal appendages) in asthmatic patients. A 
little powdered protein (prepared from a pollen, a bac¬ 
terium, an article of food, or such appendages as chicken 
feathers, animal dandruff, etc.,) is put over a shallow 
abrasion on a patient’s arm, and a drop of decinormal 
sodium hydroxide solution is placed over it (to dissolve 
the protein) quickly, if the patient is susceptible to the 
given protein; within one to ten minutes a fairly large 
urticarial wheal (depending on patient’s susceptibility) 
develops at the site of the test. When the proteins re¬ 
sponsible for the patient’s condition are established, a 
series of injections with the protein is given, usually 
with very good results. 
VIII. The Relation of Leucocytes to Infections 
The human blood is composed of the liquid part called 
plasma, and three types of cells, called, respectively: 
white blood cells or leucocytes, red blood cells or eryth¬ 
rocytes, and blood platelets; the number of erythro¬ 
cytes is 5,000,000 per cu. mm., that of the leucocytes is 
