696 PASSIVE IMMUNIZATION SERUM THERAPY 



gravity method, under ordinary conditions, at least ten minutes should 

 be consumed in administering 15 c.c. of serum. A total drop of 20 mm. 

 of mercury indicates that sufficient serum has been injected. If it is de- 

 sired to inject more, as in a severe case of meningitis, close watch should 

 be kept for other symptoms of collapse. 



3. Usually, under these conditions, less serum is administered than 

 has been advocated heretofore. It is apparent that the more potent 

 the serum, the less bulk is required and the bulk alone is an important 

 factor, for a large injection may so injure the patient as to counteract 

 any good that the serum may do. Unfortunately, there is no accurate 

 measure of the curative value of antimeningococcic serum. It is highly 

 desirable that a serum be as potent as possible, and the physician must 

 rely upon the reputation of the firm producing the serum. Efforts are 

 being made to concentrate these serums, much as antitoxin is concen- 

 trated, and this is an end very much to be desired. 



4. Blood-pressure changes are not constant in the same patient upon 

 different occasions. The pressure should be taken, after each puncture 

 and inoculation, for the administration cannot be guided by observa- 

 tions made on a previous occasion. 



Collapse during Subdural Inoculation. Carter has shown, by ex- 

 periments on dogs, that the first mechanical effects of increased intra- 

 spinal pressure were respiratory depression and marked cardiac inhibi- 

 tion. Sophian has found that similar effects may be produced during 

 subdural injections of serum in the treatment of meningitis. 



The symptoms of collapse, such as stupor, superficial or deep, ir- 

 regular and slow respiration, and dilatation of the pupils, are fore- 

 shadowed by a marked drop in blood-pressure. The pulse may con- 

 tinue good or become slow and irregular. Incontinence of urine and 

 feces may occur. 



The treatment consists primarily in discontinuing the injection. By 

 lowering the funnel, fluid is allowed to flow from the spinal canal and 

 mix with the serum. If a syringe is being used, it should be detached 

 from the needle or gentle suction made. After a few minutes the symp- 

 toms may disappear and the inoculation may be cautiously resumed 

 until the desired amount of serum has been injected; otherwise the 

 needle should be withdrawn. 



In addition to this procedure atropin and caffein may be administered 

 hypodermically in large doses, and artificial respiration resorted to if 

 necessary. It is well to have these drugs ready for injection before the 

 inoculation is begun, so that no time will be lost when they are needed. 



