1881.] NATURAL SCIENCES OF PHILADELPHIA. 467 



be within the knowledge of most observers that on the recur- 

 rence of spring, flower-buds were much larger than leaf-buds in 

 the same species, no use had been made of this fact in physiolog- 

 ical teaching so far as he knew. At the fall of the leaf, as any 

 one might see in the peach, cherry, apple, pear, maple, willows, 

 poplars, alders and numerous others, the flower-buds could scarcely, 

 if at all, be discerned from leaf-buds ; but b}- spring the flower- 

 buds had increased to double their autumn size, while the leaf-buds 

 remained exactl}^ the same. Whenever the thermometer was in 

 ever so slight a degree above the freezing point, the flower-bud 

 increased in size during the winter. The leaf-bud required a 

 higher temperature to excite it. This difference in excitability 

 ought to be of value in explaining some biological points. 



December 2t. 

 The President, Dr. Ruschenberger, in the chair. 

 Thirty-six persons present. 



The death of Henry Morris, a member, was announced. 

 The following was ordered to be published : — 



