292 NATURAL SCIENCE. November, 



Professor Farmer, whose kindness has permitted a full abstract of 

 his paper to be inserted among our articles. The discussion itself 

 afforded examples of that disagreement among biologists to which 

 Mr. Farmer alludes. Professor Zacharias was one of those who 

 held that the radiating fibres seen in a dividing cell were in no sense 

 contractile, but the expression of lines of force, and who rejected the 

 individuality of the chromosomes. Dr. Gustav Mann, on the other 

 hand, maintained the permanence of the centrosomes and the 

 definiteness of their structure, while, on the ground of physiological 

 evidence, such as that the chromatin in a gland-cell might change 

 from day to day, he denied definiteness to the chromatin of the cell. 

 The disagreement of doctors, if not the opposing evidence of acknow- 

 ledged facts, is enough to show that we are not yet in a position to 

 base elaborate hypotheses on such inconclusive evidence. While, 

 therefore, we may admit with Professor Yves Delage that Weismann's 

 theory is the only one that explains how the special characters of the 

 male and female parent are contained in the fertihsed egg, we may 

 also agree with him that the theory is contrary to the evidence at 

 present before us. We may even go so far as to maintain with Dr. 

 C. S. Minot that the interest in the celebrated theories of " The 

 Germ-plasm " is now a historical one. However this may be, there 

 is one point on which all speakers were agreed, namely, that future 

 advance will be made chiefly by the investigation of the living cell, 

 through methods which were not at the disposition of the older 

 observers. 



" Anatomical Characters " in Systematic Botany. 



In the Botanical Section, the presidential address, by Dr. D. H. 

 Scott, put the present position of morphological botany in a clear 

 light. At the outset he deplored the want of a study of the compara- 

 tive embryology of seed-plants. It is often assumed that the develop- 

 ment of the embryo from the fertilised ovum will teach us but little in 

 botany ; an opinion which is largely based on ignorance. As regards 

 the value to sysiematists of characters which those gentlemen are 

 pleased to call " anatomical," there is no doubt, as Dr. Scott himself 

 has shown, that certain well-marked peculiarities of internal structure 

 are constant in more or less definite systematic groups. Such a 

 character is the presence of bast on the inside, as well as on the out- 

 side, of the wood-bundles in several orders of dicotyledons, e.g., 

 Solanaceae, Asclepiadaceae, Apocynaceae. Similarly, Masters has 

 shown that in many conifers anatomical characters may be useful for 

 diagnosing species. In the pines, for instance, the position of the 

 large resin-canals as seen in the transverse section of the leaves, the 

 arrangement of the stomata, the branching or not of the foliar bundle, 

 are all of some value. In the most recent revision of the Acanthaceae 

 the sculpture of the pollen-grains is extensively used as a generic 



