1897] MICHOSCOPICAL JOURNAL. 5& 



"healing serum" before the nerve centers become par- 

 alyzed, the heart and kidneys become diseased and the 

 entire system invaded by the absorption of the fatal toxin. 



THE PRESERVATION OF ANTITOXIN. 



Diphtheria antitoxin is a most delicate substance, and 

 its preparation can only be safely carried on in thoroughly 

 equipped institutions where men of undoubted integrity 

 of purpose 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 it retains its activity 

 for a much longer period. 



Chloroform, camphor, sodium salicylate, carbolic acid, 

 and formaldehyde have been employed, but the prefer- 

 ence is greatly in favor of trikresol and formaldehyde. 

 Camphor seems to be particularly dangerous, since it 

 possesses but a feeble preservative action, and its strong 

 odor will prevent the detection of putrefactive processes 

 should they be established; chloroform and sodium 

 salicylate are unsuited on account of their active the- 

 rapeutic effect. 



Trikresol in a strength of but 0.5 percent protects the 

 serum absolutely; in fact, pathogenic bacteria do not 

 develop with this percentage of trikresol; it is not a poi- 

 son, as is carbolid acid, nor is it an irritant to the 

 urethral tract. A disadvantage is that it produces a semi- 

 fluorescent appearance in the serum, but the absence of 

 cloudiness is shown by permitting the light to enter 

 squarely through the vials containing the finished product. 



STRENGTH OF SERUM. 



Antitoxin is usually supplied in bottles containg vary- 

 ing quantities of serum, but of a certain number of anti- 

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



