286 PHAGOCYTOSIS— OPSONINS 



author is decidedly of the opinion that there is no way 

 of determining the dosage of a vaccine in the treatment of 

 any given case except by the residt of the first dose. Hence 

 it is his practice to make vaccines of a particular organism 

 of the same approximate strength, and to give a dose 

 of a measured portion of a cubic centimeter, judging the 

 amount by wiiat the individual or animal can apparently 

 withstand, without too violent a reaction. If there is no 

 local or general reaction, or if it is very slight and there is 

 no effect on the lesion, the dose is too small. If there is a 

 violent local reaction with severe constitutional symptoms 

 clinically, and the lesion appears worse, the dose is too 

 large. There should be some local reaction and some 

 general, but not enough to cause more than a slight disturb- 

 ance, easy to judge in human subjects, more difficult in 

 animals. In cases suitable for vaccine treatment no serious 

 results should follow from a properly prepared vaccine, 

 though the process of healing may be delayed temporarily. 

 Wright claimed, and many have substantiated him, that 

 always following a vaccination there is a period when the 

 resistance of the animal is diminished. This is called the 

 "negative phase," and Wright considered this to last as 

 long as the opsonic index remained low, and when this 

 latter began to increase the stage of the "positive" or 

 favorable phase was reached. As has been stated the 

 opsonic index is pretty generally regarded as of doubtful 

 value, though the existence of a period of lowered resistance 

 is theoretically probable from the fact that antibodies 

 already present in the blood will be partially used up in 

 uniting with the vaccine introduced and that the body cells 

 are called upon suddenly to do an extra amount of work, 

 and it takes them some time to adapt themselves. This 

 time the "negative phase" is much better determined by 

 the clinical sjTiiptoms, general and especially local. It is 

 good practice to begin with a dose relatively small. The 

 result of this is an indication of the proper dosage and also 

 prepares the patient for a larger one. The second dose 

 should follow the first not sooner than three or four days, 

 and should be five to seven days if the first reaction is severe. 



