20$ APPENDIX 



The Meiostagmin Reaction 



Weichardt called attention to the fact that the 

 union of antigen with its antibody in certain dilu- 

 tions caused an increase in the rate of diffusion, 

 i.e., gave rise to changes in the osmotic pressure 

 and of the surface tension. Ascoli showed that the 

 decrease in the surface tension arising when bac- 

 terial substances combined with their specific antigen 

 could be measured by counting the number of drops 

 per given time interval delivered from a Traube 

 stalagmometer. Thus where a mixture of normal 

 serum with extract of typhoid bacilli showed 56 

 drops, a similar mixture of serum from a typhoid 

 fever patient with the extract showed 58 drops. 

 Attempts have been made to utilize the meiostag- 

 min reaction in the diagnosis of various infectious 

 diseases, and while the results on the whole have 

 shown the correctness of the underlying principles, 

 they have also demonstrated that other reactions 

 are far more convenient and decisive. 



The Much-Holzmann Cobra Venom Reaction 



It has long been known that cobra venom haemo- 

 lyzes red blood corpuscles, and that certain cor- 

 puscles, such as those of man, dog, pig, horse, 

 rabbit, and guinea-pig haemolyze directly on mixing 

 them with cobra v-enom, while others require the 



