RECORDS. 497 



of the paper the members of the Section expressed their appre- 

 ciation of it in a few remarks, with especial reference to the 

 logical arrangement of the subject-matter. 



There being no further business, the Section adjourned at 



9:50 P. M. 



R. Gordon, 



Secretary. 



SECTION OF BIOLOGY. 



December 12, 1898. 



Thirty-one persons present, Professsor Lee in the chair. The 

 following programme was offered : 



1. F. S. Lee. The Course of Muscle Fatigue. 



2. W. K. Brooks. The Embryology of Lucifer. 



3. F. E. Lloyd. Studies in the Embryology of the Ru- 



BIACE.E. 



4. N. R. Harrington and Edward Learning. The Reac- 

 tion OF Amceba to Light of Different Colors. 



Professor Lee showed that in the different types of animals 

 studied by him in determining the course of muscle fatigue, the 

 height of the curve, which represents the lifting power, becomes 

 less and less in all cases. The reduction in height of the curve 

 is accompanied in the case of muscles from the frog and turtle, 

 by a concomitant increase of the duration of relaxation. The 

 duration of contraction is also increased slightly in the frog and 

 greatly in the turtle. In the cat neither of these secondary 

 phenomena is represented, the height of the curve, or the lifting 

 power, alone varying. The experiments show that the diminu- 

 tion of the latter phenomenon is the essential element in fatigue. 



Professor Brooks gave a brief review of his interesting obser- 

 vations on the development of Lucifer bringing out in particular 

 the essential features of cleavage and gastrulation which dis- 

 tinguish this decapod from most of its allies. 



In the discussion which followed the paper it was shown by 

 Professor Brooks that his results on the unusual mode of 



