1881.] NATURAL SCIENCES OF PHILADELPHIA. 459 



all their leaflets drooping as at night. How long they may have 

 been in this condition before being noticed is not known, but they 

 continued in that " sleeping " condition till this date (November 7), 

 the others having gone through their motions dail}^ till now. 

 During the last few days, however, tlie thermometer having once 

 been nearl}^ down to freezing point, only the two or three upper 

 pinnules on the leaves have retained the power to move. The 

 paralyzed leaves were in every respect as health}^ looking as the 

 others, but they were, all three, somewhat smaller. If these had 

 been all together at the lower or upper end of the branch, the 

 peculiarity might have been referred to some cause connected 

 with maturity ; but the first paralyzed leaf was the third from the 

 top, the next the fifth, and the other the sixth ; that is to say, 

 there were leaves with perfect motile functions above and below 

 these, as well as one among the three. Though for the six weeks, 

 at least, they had lost the power of motion, the color and general 

 healthy appearance of the leaves were precisely the same as the 

 others. There was no difference whatever except in the length 

 of the common petiole and size of the leaves. They were about 

 three-fourths the ordinary size. The upward movement of the 

 pinnules in this species is confined to those exposed to the sun- 

 light ; those shaded by even their own foliage have not the power. 

 Mr. Meehan had previoush' called the attention of the Academy 

 to the fact that a large number of plants draw the upper surface 

 of the leaf together in bright light, as illustrations of which he 

 mentioned now : Halesia tetraptera^ Cornus JiojHda, Co7'nus mas 

 and Magnolia acuminata. 



November 15. 

 The President, Dr. Ruschenberger, in the chair. 

 Thirty-one persons present. 



November 22. 



The President, Dr. Ruschenberger, in the chair. 



Twenty-nine persons present. 



A paper entitled " On a foetal Kangaroo and its Membranes," 

 by Henry C. Chapman, M. D., was presented for publication. 



The death of the Rev. Z. M. Humphrey, a correspondent, was 

 announced. 



