52 



Scientific Proceedings (26). 



due to the direct action of the substances upon the respiratory- 

 center or whether they are reflex effects due to the action of the 

 substances upon nerve fibers. If, however, we cover the lower 

 limbs of the frog, treated as above, with a sheet of filter paper 

 saturated with N/10 HC1, after 3 or 4 minutes of violent struggling 

 the frog becomes quiet and the respirations, at first inhibited, are 

 resumed ; although occasional convulsive movements occur, these 

 become less and less frequent and respirations continue except 

 during the actual convulsions. The rate of the respirations is, 

 however, unaltered for the first six minutes ; in ten to twelve min- 

 utes they may be accelerated 10 per cent, but not more. Now the 

 time which elapses before the respirations are quickened is only 

 1 to 2 minutes when the acid is applied directly to the medulla 

 and the animal usually does not struggle at all. Moreover, the 

 two effects, the effect upon the respiratory center and that upon 

 nerve fibers can readily be distinguished from one another in the 

 case of N/10 oxalic acid. At first the normal effect of an acid 

 upon respiration is observed, namely a marked quickening of the 

 rhythm so that after 10 minutes the rate may be doubled. If 

 further applications of oxalic acid be made the rate continues to in- 

 crease until over one half hour after the first application of oxalic 

 acid when the muscles of the whole animal go into prolonged 

 tetanic contractions ; the former effect is that of the acid upon the 

 respiratory center, the latter effect is that of the oxalic acid anion 

 upon nerve fibers. 



The results are such as to indicate that the processes occurring 

 in nerve cells during the passage of a reflex are of the nature of 

 oxidations and that they are accelerated by acids. 



28 (284) 



Metaplasia and metastasis of a rat tumor. 

 By SIMON FLEXNER and J. W. JOBLING. 



[From the Rockefeller Institute for Medical Research.~\ 



We reported to this society on several previous occasions some 

 facts regarding a tumor of the rat which we have propagated for 

 more than two years. This tumor is now in its twelfth genera- 



