V0l iS*6 in ] Recent Literature. 1 67 



way." This is the matter in a nutshell. Moulting birds have not fallen 

 into the hands of some of the older observers and they have jumped to 

 the conclusion that no moult had taken place. Even so, it is not easy to 

 understand why the observations of Bachman, Homeyer, Brehm and 

 others who have traced the various stages of moult in many species should 

 have had so little weight against the opinions of Ord, Yarrell, Schlegel, 

 Fatio, Gatke, and the other delusionists. But since we find the latter 

 still supported by reputable writers of today, the present paper is all the 

 more welcome, and ought to stimulate further investigations ; for if it 

 can be proved that a certain species acquires by moult the plumage that it 

 theoretically should acquire by recoloration and rejuvenation, theory 

 begins to totter. This is exactly what Dr. Allen does, and he cites a 

 number of species in his support, so that the theories for the most part 

 become respectable ruins. The fact seems to be that few observers have 

 had sufficient material on which to build, and if the time devoted to 

 inventing theories to fit the material had been intelligently spent in 

 accumulating such specimens as were needed, the many fanciful and 

 superfluous hypotheses now current would not have arisen. It is hardly 

 profitable to dwell upon them and they may be read in the paper now 

 under discussion. Neither is a microscope necessary to controvert them. 

 When, for example, Severtzof by aid of this instrument describes a color 

 bearing fluid ascending in the old feather bv capillarity, exuding from the 

 broken barbs, or depositing its pigment in successive layers on the cell 

 walls, what do such observations mean if the feather is really renewed by 

 a moult? Dr. Allen, by proving the delusionists wrong in part, believes 

 them wrong in all their conclusions and gives adherence to the opinion 

 of Bachman who, in 1S39, said : "If the feathers in birds, then, which have 

 been long stationary in their growth, are capable of receiving a new set of 

 secretions, and of assuming opposite colors, we must seek for some new- 

 law of nature not hitherto discovered." — J. D., Jr. 



The Mockingbird and Yucca aloifolia. — The sixth annual report of the 

 Missouri Botanical Garden 1 contains one paper of especial interest to 

 ornithologists. It is entitled ' Studies on the Dissemination and Leaf 

 Reflexions of Yucca aloifolia and other Species,' by Herbert J. Webber, 

 and the facts it brings to light are strikingly illustrative of the close 

 relations which economic ornithology and botany may have for each 

 other. The fruit of this species of yucca has an edible sticky pulp, in 

 which the seeds are imbedded without a core. Mr. Webber finds that the 

 Mockingbird is particularly fond of this fruit and is an important agent 

 in the dissemination of the seeds. In eating the pulp some of the seeds 

 stick to the bill and are shaken off, falling at a suitable distance from 

 the plant to allow of germination and growth. But in their haste and 



1 Missouri Botanical Garden. Sixth Annual Report. St. Louis, Mo. Pub- 

 lished by the Board of Trustees, 1S95. 



