60 THE AMERICAN MONTHLY [Feb. 



and we would strongly recommeud that a fixed, standard 

 of a definite number of immunizing units be secured in 

 each ccm. of serum. While this involves extra labor, it 

 prevents confusion on the part of the physician, and the 

 end is well worthy of the increased labor. If serum is 

 produced of a strength of 125 units per com., it may be 

 mixed with an equal amount of serum containing 75 units 

 per com.; the result is that each ccm. will contain 100 

 immunizing units, and if 500 units are desired to be ad- 

 ministered, 5 ccm. will be understood as the requisite 

 amount to be injected, etc. 



HIGH POTENCY SERUM. 

 It is a matter of gratifying interest to Americans that 

 serums of the highest antitoxic values have been prepared 

 in our country. Serums are now produced of which each 

 ccm. contains as much as 800 units, and we confidently 

 believe that as much as 1,000 antitoxic units to the ccm. 

 will be produced in the near future. This overcomes the 

 chief objection that has been urged against the serum 

 even by its warmest advocates. More prompt absorp- 

 tion will take place, insuring quicker results, besides the 

 attendant dread caused by the large instruments neces- 

 sary for the introduction of larger amounts of weaker 

 serum will be avoided, as much as 2,000 units being ad- 

 ministeied in an ordinary two ccm. or 30 minim syringe. 



DRIED SERUMS. 



Dried serums are much less active than fluid or fresh 

 ones. They are prepared by addition of aluminum or 

 ammonium snl])hate, with subsequent precipitation of the 

 antitoxin by a 1 per cent soda solution or by inpissa- 

 tion. They have given fairly good results, but cause 

 greater irritation than do the fluid serums, and not being 

 freely soluble, cause annoyance in administration and 

 give greater opportunities for contamination in their pre- 

 paration and dilution for administration. 



