35 



very important one that "there is an equal tendency toward reduction 

 and toward increase in the number of prsesacral vertebrae." He oöers 

 us no hypothesis in the place of the one he has destroyed but shows 

 us, without making the statement, that numerical anomalies are vari- 

 ations round a mean. 



The paper by Adolphi, so far as it is confined to facts and to 

 observations, is truly an admirable one. He analyzes his own observ- 

 ations as well as those of others and shows very conclusively that the 

 variations at the top of the thorax, at the lower border of the thorax 

 as formed by the ribs, at the junction of the thorax and loins, and at 

 that of the loins and sacrum, all have a tendency to vary simultane- 

 ously in the same direction. There had indeed been many observations 

 of this condition, but Adolphi's tables are very convincing. Through 

 him this fact may be said to be established. It is significant in con- 

 nection with Bardeen's statement that variation is as likely to occur 

 in one direction as in the other. Unfortunately Adolphi's paper had 

 been written before Bardeen's appeared, and under the impression 

 that Rosenberg's theory still survived, the former author indulged in 

 some speculations as to the future of the race which are more brilliant 

 than convincing. 



Angel and Sencert describe some interesting spines and devote 

 themselves chiefly to the discussion of the question. They hold very 

 firmly to Rosenberg's hypothesis, ■ and seem at times almost to use 

 it as a starting point. They disprove very convincingly the theory of 

 intercalation and excalation, showing incidentally that the position of 

 the nervus furcalis is very uncertain. It may vary with the vertebrae 

 and also independently of them. Irregular segmentation pleases them 

 somewhat better, but they are not at all disposed to accept my argu- 

 ments in its favor. They say "Dwight ne pent Stayer son opinion 

 par aucun fait, il nous faudrait autre chose qu'une impression per- 

 sonnelle pour admettre dans ces cas une irregularity de segmentation". 

 They account for the changes by the movement of the pelvis ; and take 

 my spine 267 of eleven thoracic vertebrae and cervical ribs in which 

 lumbar, sacral and coccygeal regions are practically normal, as simply 

 one in which the process is further advanced than usual. I should 

 like to point out that I had written concerning that spine as follows: 

 "Let us suppose that the spine had been divided in the middle of the 

 thoracic region and the upper half lost. On examining the lower half 

 all would agree that it is practically a normal spine, because no one 

 would know that the last thoracic is the 18th vertebra and the last 

 lumbar the 23rd. It would be taken for granted that they are the 



