202 CHARLES L. PARMENTER 



review them extensively. But Delia Valle's attitude and his 

 conception of what constitutes clearness and certainty may be 

 better understood in the light of some of these citations of 

 chromosome variations, especially in the Amphibia, which he 

 presents as valid evidence of variation in chromosome number. 

 He quotes ('09, p. 35) Flemming ('81, ['82] p. 51) and Rabl 

 ('84, ['85] p. 248 to 250) as reporting variations of from seventeen 

 to twenty-four in the gill epithelium of Salamandra maculosa. 

 Flemming explicitly states (pp. 51 and 52) that in the three 

 cells which admit an exact count there are twenty-four chromo- 

 somes, that in about twenty other cells he counted from seven- 

 teen to twenty-four, but was not certain of the number, and 

 assumed that there were twenty-four. Rabl says ('85, p. 248) 

 that up to that time only eleven unquestionable counts had been 

 made and each of them showed twenfy-four chromosomes. In 

 no exact counts in any cell had a different number been found. 

 Delia Valle seems to think that Torok's ('88) figures of erythro- 

 cytes of Salamandra maculosa show a variation. This work 

 was not concerned with chromosome number and the figures 

 were not intended to show the number of chromosomes in the 

 cell. His citations of the work of Carnoy and Lebrun ('00) on 

 Rana temporaria, and of Lebrun ('02) on Diemyctylus and Bom- 

 binator may be criticised because the authors were primarily 

 concerned with other considerations and only gave approximate 

 number determinations. Winiwarter ('00, p. 699), as cited by 

 Delia Valle, reports a variation of chromosome number in the 

 rabbit; but he states that he is uncertain of his counts. The 

 variations reported by Barratt ('07, p. 376), in proliferating 

 epithelium of the rabbit are in pathological tissue, and, more- 

 over, his counts are uncertain. Montgomery ('10) has shown 

 that many other such citations are misinterpreted. 



The above cases represent Delia Valle's inexact and uncritical 

 attitude in relation to data that seem to serve his purpose, and 

 this creates the suspicion that his attitude interfered with the 

 accuracy of his observations when he counted the chromosomes 

 in his own material. This suspicion approaches a probability 

 in view of the fact that numerous competent investigators who 



