504 



SCIENCE. 



[N. S. Vol. XXIII. No. 587 



TH!e new YORK ACADEMY OF SCIENCES. 

 SECTION OP BIOLOGY. 



The January meeting was devoted to re- 

 ports by members who had attended the scien- 

 tific meetings at New Orleans and Ann Arbor. 



At the February meeting Professor Britton 

 presided in the absence of Vice-president 

 Crampton. Professor P. S. Lee presented the 

 results of his recent studies on ' Acid and 

 Fatigue.' In previous communications to the 

 academy the author discussed the physical 

 phenomena of fatigue and the relation to them 

 of lack of carbohydrate. The present paper 

 presents the results of further researches on 

 the causation of fatigue. The physiological 

 action on muscle of sarcolactic acid, potas- 

 sium sarco-lactate, mono-potassium phosphate, 

 and carbon dioxide has been studied in detail. 

 All of these substances are markedly fatiguing, 

 their action consisting in general of a diminu- 

 tion of lifting power and a slowing of con- 

 traction. These substances, which are pro- 

 duced during muscular activity, are , rightly 

 named fatigue substances. The author be- 

 lieves, moreover, that fatigue in many patho- 

 logical states, such as diabetes mellitus, fevers, 

 carcinoma, anaemia, various disorders of di- 

 gestion and inanition, is largely due to the 

 pathological acids that are present and pro- 

 duce the so-called acid intoxication of these 

 diseases. He finds, for example, B-oxy-butyric 

 acid, and its salts, which are characteristic of 

 diabetes mellitus, to be fatiguing, like the 

 physiological acid fatigue substances. Not 

 unfrequently in pathological, as in normal, 

 states both lack of carbohydrate and accumu- 

 lation of acid are present as factors in the 

 causation of fatigue. This is notably so in 

 diabetes, fevers and inanition. 



Dr. B. T. Terry gave a resume of recent 

 work on the spirochsete of relapsing fever. 



Dr. C. W. Hahn called attention to the pro- 

 posed biological survey for the state of New 

 York. M. A. Bigelow, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 



A CASE OF ISOLATION WITHOUT ' BARRIERS.' 



I WAS glad to see Professor J. A. Allen's 

 article on ' barriers ' in a recent number of 



Science (February 23, p. 310), not only be- 

 cause it convinced me that we are practically 

 upon the same standpoint, but also because it 

 has directed my attention to a possible im- 

 provement in the expression of my views. 



I have maintained^ that in cases of a wide 

 distribution of a species, where there are dif- 

 ferent forms (varieties) within the range, 

 which pass into each other, no continuity of 

 ecological (bionomic) conditions is present. 

 The word ' continuity ' apparently does not 

 exactly express what I meant to say, and 

 Professor Allen, in the article referred to, 

 defiiies the question again, and asks whether 

 a ease, where there are no barriers of any 

 description, and where the different conditions 

 of the extremes of the range of the supposed 

 species pass into each other, would fall under 

 my definition of discontinuity of bionomic 

 conditions. If this should be so, he believes 

 that we understand each other. 



Indeed, this is the case. As I have said in 

 the former note, I consider this the first step 

 toward complete isolation. Since I believe 

 that species are formed gradually, by small 

 steps, out of varieties, and that only complete 

 isolation is the criterion by which it is pos- 

 sible to judge whether a certain form is a 

 species or not, it necessarily follows that com- 

 plete isolation is also attained by degrees, and 

 the first step in this direction is a differentia- 

 tion of external conditions within the area of 

 an existing species. Although, in the begin- 

 ning, gradual transitions are present, and al- 

 though the different conditions form a con- 

 tinuous series from one extreme to the other, 

 there is no uniformity, and I possibly should 

 have used the latter word, instead of ' con- 

 tinuity.' 



On account of the transitions present in 

 such cases, isolation is not yet complete, and 

 we can not distinguish species, but only varie- 

 ties. But if the transitions disappear, and 

 isolation becomes complete, the paramount 

 condition is fulfilled for the distinction of 

 species. In many, possibly in most cases, 

 complete isolation is marked by more or less 



• Science, January 12, 1906, p. 71. 



