Mat 13, 1904.] 



SCIENCE. 



767 



themselves written less successful books or 

 articles on the same general subject. 



5. The critics present denials, dogmatic as- 

 sertions, negative testimony. Not one particle 

 of positive evidence has yet been presented 

 against the books which are so vigorously con- 

 demned. Meanwhile the fact remains that, 

 though six or seven volumes and a score of 

 articles have already been published, only two 

 slight errors have thus far been pointed out, 

 and they were promptly and gratefully 

 acknowledged. 



Other facts and considerations will undoubt- 

 edly suggest themselves, but perhaps it were 

 well to consider these first in forming one's 

 judgment as to the books and their critics. 

 Wm. J. Long. 



Stamford, Conn., May 7, 1904. 



[We hope that this discussion will not be 

 carried further. — Editor.] 



THE METRIC SYSTEM. 



To THE Editor of Science: The suggestion 

 of Professor W. Le Conte Stevens that a 

 compromise be made between the metric and 

 the British system of weights and measures, 

 making a foot the fourth part of a meter and 

 an inch two per cent, smaller than the British 

 inch, might be a good one if the English- 

 speaking race were to disappear from the 

 earth, and all its tools and its technical lit- 

 erature be destroyed, but as long as that race 

 continues to use its existing tools and books, 

 so long must the inch persist with its present 

 value. His article is useful, however, in show- 

 ing the impossibility of the general adoption 

 of the metric system in its present form by 

 the people of this country. He well says : 

 " What may be the form taken by legisla- 

 tion in England and the United States, the 

 people can not be compelled to adopt nomen- 

 clature that is thrust upon them as a substi- 

 tute for that to which they have always been 

 accustomed." Wm. Kent. 



ICHTHYOLOGY IN THE ' ENCYCLOPAEDIA 

 AMERICANA.' 



To THE Editor of Science: Eef erring to 

 Dr. Gill's note on the ' Ichthyology of the En- 



cyclopsedia Americana,' I may say that he is 

 •quite right in supposing that the proofs of the 

 figures which illustrate my article on fishes 

 were not submitted to the author. Many of 

 these seem to be wrongly named as noted by 

 Dr. Gill. David S. Jordan. 



SPECIAL ARTICLES. 



THE MULTI-NIPPLED SHEEP OF BEINN BHREAGH.* 



On two former occasionsf I have had the 

 honor of presenting communications to the 

 academy concerning the multi-nippled breed 

 of sheep on my farm at Beinn Bhreagh, near 

 the town of Baddeck, Nova Scotia. 



It will be remembered that in 1889, upon 

 the purchase of some property at Beinn 

 Bhreagh I found myself in possession of 

 a flock of sheep; and that in the spring of 

 1890, one half of the lambs born upon the place 

 turned out to be twins. 



This large percentage of twins led me to 

 examine the mothers of all the lambs with 

 the object of discovering, if possible, some 

 peculiarity that would enable us to distinguish 

 twin-bearing ewes from others. 



Upon examining the miUt-bags of the sheep 

 a peculiarity was observed that was thought 

 might be significant. Normally, sheep have 

 only two nipples upon the milk-bag, but in 

 the case of several of the sheep examined, 

 supernumerary nipples were discovered which 

 were embryonic in character and not in a func- 

 tional condition. Some had three nipples in 

 all, and some four. Of the normally nippled 

 ewes 24 per cent, had twin lambs; but of the 

 abnormally nippled 43 per cent, had twins. 

 The total number of ewes, however, was so 

 small (only 51) as to deprive the percentages 

 of much significance. Still the figures were 

 suggestive of a possible correlation between 

 fertility and the presence of supernumerary 

 nipples, and it seemed worth while to make 

 an extended series of experiments to ascertain 

 (1) whether, by selective breeding, the extra 

 nipples could be developed so as to become 

 functional, and (2) whether ewes possessing 

 four functional nipples instead of two would 



* A paper read before the National Academy of 

 Sciences in Washington, D. C, April 21, 1904. 

 t See Science, Vol. IX., May 5, 1899, pp. 637. 



