276 Bacterio- vaccines 



perature begins to fall, it is replaced. Thus by alternately heating and re- 

 moving the source of heat for sixty minutes, the destruction is affected. 



If there are many of the small ampules, containing different doses 

 or different cultures, each separate lot may be done up in a piece of 

 gauze, and labeled. 



J. H. Small uses orange-colored "string tags" for this purpose, 

 writing upon them with either pen or pencil, and fastening them to 

 the gauze packages. In the water of the water-bath, the writing 

 does not wash off the tag, but the color comes out and gives the 

 water an orange tinge. This is found to be of the greatest use, 

 for as one or more of the factory-made ampules commonly cracks in 

 the water-bath, the color penetrates the contained fluid. Upon 

 removal from the water-bath, to glance at each ampule will inform 

 the observer whether it is cracked or not, through the change in the 

 the color of the contents. The tags, therefore, subserve a double 

 purpose. 



After heating, one of the ampules can be opened and a drop of the 

 contents transferred to a tube of culture to make sure that the 

 bacteria are no longer alive. 



The vaccine is now ready for use, but in what dose shall it be ad- 

 ministered? There is no other information upon this subject than 

 that which is derived from the experience that certain doses seem to 

 accomplish good without producing ill effects. Thus experience 

 with doses at first selected arbitrarily has led to a fairly accurate 

 standard dosage. As the beginning dose for most vaccines 50-250 

 millions may be recommended, to he increased to 1000 milhons or 

 more, the injections being given every four or six days or as con- 

 trolled by the opsonic index. 



The benefit of the vd,ccine is commonly supposed to depend upon 

 the stimulation of the phagocytic cells of the body. This is very 

 probably the case, but when the bacterial bodies are administered, 

 their dissolution results in the liberation of the contained endo-toxin, 

 and when the entire culture is given, endo-toxins and perhaps exo- 

 toxins and other substances are also given so that the increased 

 phagocytosis is not likely to be the only effect of the treatment. 



A. E. Wright who is a firm believer in the stimulating influence 

 upon the cells seeks to control the dosage and estimate the value of 

 the injections by such study of phagocytic activity, as is shown in 

 the next chapter. If after an injection of vaccine, the phagocytic 

 activity of the leukocytes is diminished (negative phase) harm is 

 supposed to have been done and the inference is drawn that the dose 

 was too large; if, on the other hand, the phagocytic activity is 

 increased for the respective organism, good is supposed to have been 

 done, and at the next injection the same or a larger dose may be given. 



Besredka and Metchnikoff* have modified the vaccines by what 

 is called sensitization. This they accomplish by treating the bacteria 

 * Ann. d. I'lnst. Pasteur, i'9i3, xxvii, 597- 



