90 



SCIENCE 



[N. S. Vol. XLII. No. 1072 



number of chemical individuals and to differ- 

 entiate a vastly larger number. Per simple 

 differentiation, however, it should be under- 

 stood that it is not necessary that any data be 

 knovsm. since sufficient may usually be obtained 

 in five minutes or less. 



It is obvious that by the use of petrographic 

 methods in chemical work an immense amount 

 of time can be saved, a saving that overwhelm- 

 ingly counterbalances the initial cost of equip- 

 ment and the rather unimportant trouble of 

 learning the methods. With numerous sub- 

 stances the necessity for tedious qualitative 

 analysis can be obviated or at least greatly 

 limited. Eeagents or precipitates, where ex- 

 tremely accurate results are not sought, may 

 be examined for purity with scarcely more 

 than a glance. This is of great value in vari- 

 ous phases of drug examination or general 

 inspection work. In this laboratory the petro- 

 graphic microscope has supplanted a large 

 amount of routine chemical analysis with a 

 consequent saving of both time and reagents. 



This paper is written with the purpose of 

 calling to the attention of chemists the fact 

 that, while the petrographic microscope can 

 never entirely supplant chemical analysis, it 

 may be and actually is an aid which can not 

 fail to be of very great service both to the 

 research and to the commercial worker. 



William H. Fry 



Bureau of Soils, 

 V. S. Department of Agriculture, 

 Washington, D. C. 



to the american physical society 

 In his announcement of June 25th to the 

 members of the American Physical Society, 

 Professor Cole expresses the fear that there 

 will not be room on the program of the San 

 Francisco meeting of August 6 for many 

 papers from eastern members. Evidently Pro- 

 fessor Cole has overestimated the numbers or 

 the scientific activity of the members of the 

 Physical Society on the Pacific Coast. 



It is the belief of the coast committee on 

 program that there will be ample time for the 

 reading of all papers that our eastern mem- 

 bers are willing to present, and accordingly 



this committee especially invites papers from 

 the eastern members at this session. 



Fernando Sanford, 



E. P. Lewis, 



For the Committee 



A CORRECTION 



May I be allowed to call attention to a 

 printer's error in my article entitled " Some 

 Reasons for Saving the Genus," which was 

 published in Science for June 18, 1915 ? The 

 concluding sentence (p. 902) was rendered en- 

 tirely ineffective by the omission of a line. The 

 sentence should read: "In this conflict the 

 ' general biologist ' should, I think, lend his 

 support to that faction which shows the higher 

 regard for the interests of the scientific public." 

 F. B. Sumner 



A chicken with four LEGS 



On December 15, 1914, a chicken was 

 hatched out of one of our settings which had 

 four legs. It lived from one evening to the 

 next noon when it was stepped upon by the 

 mother-hen and killed. It seemed to be normal 

 in every other respect, eating and walking 

 about like the others, of the usual markings 

 and full size but not unusually large. 



The two extra legs were at either side of the 

 extreme rear of the body, appeared to be com- 

 plete in all the essentials, having the three 

 main toes and the small toe together with toe- 

 nails. These extra legs were about two thirds 

 the size of the principal ones, were a lighter 

 yellow in color and had the toes facing the 

 rear, the opposite to the ordinary ones. 



In walking, the chicken curled up the extra 

 legs behind it, using only the principal ones. 



It was of the Plymouth Rock breed and 

 nothing unusual was noticeable about any of 

 the eggs of the setting. There did not seem 

 to be anything unusual in the fertility of the 

 eggs — hatchings running from two to eleven 

 chickens. Six eggs of the setting in question 

 hatched and all the remainder appear entirely 

 normal. 



This specimen was sent to the Museum of 

 the Escuela de Agricultra here. 



C. T>. Perrine 



C6RD0BA, December 22, 1914 



