186 THE MICROSCOPE. Dec. 



o\in. Unfortunately we cannot arrive at the exact dose 

 for therapeutic application by thi^? method, since the hu- 

 man subject is much more suscejjtible to the poison than 

 the guinea pig, and we have no possible means of deter- 

 mining the amount of loxin secreted by the diphtheria 

 bacilli in the patient suffering with diiditheria ; there- 

 fore if any error in amount of antitoxin administered is 

 made, it should be its administration in excessive rather 

 rather than in an insufficient quantity. 



Appreciating however, that the effect of diphtheria an- 

 titoxin is only in neutralizing the toxin of dii)htheria, we 

 know how necessary it is to make application of this 

 "healing serum" before the nerve centres become para- 

 lyzed ; the heart and kidneys become diseased and the 

 entire system invaded by the absorption of the fatal 

 toxin. 



Diphtlijeria antitoxin is a most delicate substance, and 

 its preparation can only be safely carried on in thor- 

 oughly equipped institutions, where men of undoubted 

 integrity and ability are in supervision. 



While antitoxin is a delicate substance, yet, when a 

 proper preservative in a sufficient amount is used, and it 

 is hermetically sealed in sterile vials, it will preserve its 

 strength and antitoxic value for at least six months; in- 

 deed repeated experiments prove that its retains its activ- 

 ity for a much longer period. 



Antitoxin is usually supplied in bottles containing 

 varying quantities of serum, but of a certain number of 

 immunizing units. This is apt to lead to confusion, and 

 we would strongly recommend that a fixed standard of a 

 definite number of immunizing units be secured in each 

 cc. of serum. While this involves extra labor, it pre- 

 vents confusion on the jiart of the physician, and the end 

 is well worthy of the increased labor. If serum is pro- 

 duced of a strength of 125 units per cc. the result is that 

 each cc. will contain 100 immunizing units, and if it is de- 



