628 



ACTIVE IMMUNIZATION 



Collection. Ordinarily, within forty-eight hours of vaccination, 

 the scratches are pinkish, slightly raised, and papular, and within five 

 or six days, depending upon the rate of development of the vaccine 

 vesicles, the virus should be ready for collection (Fig. 127). The calf 

 is killed and placed upon the operating-table. The appointments of the 

 operating-room are usually equal to those in a well-equipped hospital 





y 



FIG. 127. PRODUCTION OF COWPOX VACCINE. 



Note the lines of cowpox lesions over the abdomen and flanks of the calf. The 

 surgeon is about to cleanse this area in a thorough and careful manner, after which 

 the cowpox material is removed with a curet and collected in a sterile vessel. All 

 precautions are taken to insure as thorough aseptic technic as possible. 



operating-room, being supplied with all conveniences and means for 

 carrying out a careful, painstaking, and aseptic technic. 



The exposed parts are covered with sterile sheets. The operator 

 and his assistant are clad in aseptic gowns. The vaccinated field is 

 thoroughly scrubbed with soap, sterile water, and gauze, and mopped 

 with sterile gauze. Crusts are carefully picked off, and the soft, pulpy 



