and Laboratory Methods. 1-^01 



cells from which the buds arise ? Of four hundred scale leaves tried, over half 

 regenerated. The location of the regeneration buds was mostly on the flanks 

 at the leaf base. On older scales there is a greater tendency for the buds to 

 appear on the median line of the scale. If the scale be divided in two by a cross 

 section, regeneration only occurs from the basal half. The power of regenera- 

 tion diminishes with the distance from the leaf base. Many hnd prhnoi'di a may 

 start together and only one survive. If a pfimordia/ outgrowth be removed 

 by cutting, then numerous primordia arise about the margin of the cut surface. 

 No anatomical diiTerence could be noticed between the epidermal cells from 

 which the buds arise, and the adjoining ones, and Palisa concludes that they 

 may arise from any of the epidermal cells. 



The second question concerns the development of the buds. They always 

 arise from a group of epidermal cells. Sections through the scales show the 

 hypodermal cells to take no part whatever in the development. The first appear- 

 ance is a dome-shaped elevation on the surface, which soon becomes prominent 

 above the surrounding tissue. The outline of the original epidermal cells remains 

 quite distinct after many divisions have occurred. When the outgrowth reaches 

 a considerable size, an apical cell is organized and further growth proceeds from 

 it. From its segment the frond is formed and from the lower part of the frond the 

 roots spring. In the case of outgrowths which arise later and are more scattered 

 and thus have more space, the growth from each epidermal cell may organize an 

 apical cell and originate a bud. Between these methods there is every stage of 

 gradation. A number of apical cells may start, close to one another, but one 

 usually develops more rapidly than the rest, draws the nourishment from them, 

 and they cease to function. 



Palisa compares the developmental history of these buds with that of the 

 normal adventitious buds which always arise from a single epidermal cell. 

 Chicago. W. B. MacCalLUM. 



CYTOLOGY, EMBRYOLOGY, 



AND 



MICROSCOPICAL METHODS. 



Agnes M. Claypole. 



Separates of papers and books on animal biology shoiild be sent for review to 



Agnes M. Claypole, Sage College, 



Ithaca, N. Y. 



CURRENT LITERATURE. 



Nussbaum, J., u. Prymak. T. Zur Entwickel- This work demonstrates that the leuco- 



ungsgeschichte der eymphoiden Elemente cytes of the thymus in bony fishes 

 der Thymus bei den Knochenfischen. Anat. . , , -r , ■ ^ r .1 



Anz. 19: 6-iQ, iqoi. arise largely if not entirely from the 



epithelium ; this is a point of very 

 general significance in regard to the germ layer origin of the lymphoid elements. 

 The special point of interest and importance is the entire harmony of this work with 

 that of J. Beard reviewed in March, 1901, of the Journal of Applied Micros- 

 copy AND Laboratory Methods. a. m, c. 



