SERUM DISEASE. 397 



It has been suggested that by passive sensitiza- 

 tion of guinea-pigs with patient's serum, we can 

 ascertain whether or not there is any danger in 

 second injections of serum. 



It has also been suggested that a cutaneous test, 

 similar to a v. Pirquet tuberculin test, be made 

 with horse serum to find out whether or not hyper- 

 susceptibility to horse serum be present. 



