Dynamic Importance of Auricular Systole 325 



normally, an additional ventricular rilling takes place or at least 

 the intra-ventricular pressure is increased. This operates to 

 lengthen the duration of the systolic ejection phase and through 

 this the length of the entire systole. When the synergic auricu- 

 lar contractions are in abeyance as in auricular fibrillation, the 

 ventricles either fill less efficiently or at least the initial tension is 

 not as high, in spite of a considerable venous pressure in the 

 veins. 



Summary: 1. The duration of ventricular systole and its ejec- 

 tion phase are influenced at corresponding heart rates by the 

 diastolic filling and the initial pressure of the ventricles, as dem- 

 onstrated by recent experimental work. 



2. The duration of these periods in hearts with auricular fibril- 

 lation is shorter than normal at corresponding heart rates, even 

 in spite of the higher venous pressures present. 



3. These intervals increase when the heart reverts to a normal 

 mechanism. 



We conclude, therefore, that these observations give probable 

 if indirect evidence of the dynamic importance of auricular 

 systole in the normal heart beat in man. 



159 (2119) 



Kahn precipitation test for syphilis — improved procedure. 

 By R. L. KAHN. 



[From the Bureau of Laboratories, Michigan Department of 

 Health, Lansing, Michigan.} 



The precipitation test for syphilis proposed by the author 1 

 called forth favorable comment from a number of investigators 

 (Keim and Wile, 2 Herrold, 3 Young, 4 Ide and Smith, 5 Holmes 6 



1 Proc. Soc. Exp. Biol, and Med., 1922, xix, 182; Arch. Derm, and SyphiL, 

 1922, v, 570 and 734, vi, 332. 



2 J. Amer. Med. Ass'n., 1922, Ixxix, 870. 

 ZJ. Amer. Med. Ass'n, 1922, barix, 957. 



4 J. Amer. Med. Ass'n, 1922, lxxix, 1674; Amer. J. of Public Health, 1923, 

 xiii, 96. 



5 Arch. Derm, and SyphiL, 1922, vi, 770. 

 *J. Mo. State Med. Ass'n, 1922, xix, 479. 



