INFECTION, IMMUNITY, AND SPECIFIC 



THERAPY 



PART I 



CHAPTER I 



GENERAL TECHNIC 



IN this chapter simple methods are described for preparing capillary 

 pipets and similar apparatus usually made in the laboratory, and a 

 few general directions are given concerning the preparation of glass- 

 ware and other material employed in the various methods described 

 in succeeding chapters and in experimental work. 



It may be well here to utter a word of caution to the inexperienced 

 against observing undue haste in performing the manipulations of im- 

 munologic technic. Careful and painstaking work is essential in order to 

 secure reliable and successful results, and should never be sacrificed for 

 speed, the latter being attained only by experience. 



CENTRIFUGE 



1. A good centrifuge is one of the chief requisites of a laboratory 

 equipment. While any good instrument will answer, preference should 

 be given to the larger types, fitted for holding both 15 c.c. and 50 c.c. 

 centrifuge tubes, propelled by electricity, and mounted on a concrete 

 block in the laboratory (Fig. 1). 



2. The machine must be well oiled. 



3. The counter tubes should be of the same weight it is our cus- 

 tom to weigh the tubes on a small balance, and adjust the counter 

 tubes until both are of equal weight. 



4. The centrifuge tubes should rest loosely upon a rubber disc 

 or wad of cotton in the bottom of the metal tube or cup; otherwise 

 centrifuge tubes are quite likely to be broken, especially if the machine 

 is run at high speed. 



5. The machine should be started and stopped slowly, and un- 

 necessary speed and long running time should be avoided. 



6. Never centrifugalize with cotton plugs in the centrifuge tubes. 



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