400 SECTIONAL TRANSACTIONS.— K. 



newest species (or genera). All these questions have nothing to do with adapta- 

 tion. Adaptation is not the same as utility. There may be characters which are 

 useful in reference to certain conditions of life whose origin was independent of 

 those conditions. But it is more important to consider cases in which structures 

 have been changed to perform new and essential functions in relation to chanored 

 conditions, e.g. respiratory organs in embryos, larvae and adults, or mammary 

 glands. In most cases these organs show recapitulation which is not (with a 

 few special exceptions) exhibited by mutations. The modern discoveries con- 

 cerning hormones or int€rnal secretions show how such modifications with 

 recapitulation may have been produced by stimuli and functional exercise 

 (/) Dr. H. Wager, F.E.S. 



15. Prof. J. H. Priestley. — The Endodermis: A Study in Causal 



Anatomy. 



In the angiosperm root primary, secondary and tertiary stages succeed 

 one another during the development of the endodermis. The development of 

 the primary endodermis behind the root growing-point appears to be causally 

 connected with (1) the fat metabolism of the apical meristem, (2) the change's 

 proceeding in the membranes of the meristematic cells, (3) the diffusion of 

 substances from the differentiating phloem. The appearance of the secondary 

 endodermis in the root is to a certain extent under experiinental control. 



In the angiosperm stem a primary endodermis is usually present in under- 

 ground rhizomes, submerged water-plants, and in etiolated shoots, but it may 

 be replaced by a starch sheath. The relation of the starch sheath to the 

 primary endodermis is considered. 



The appearance of a secondary endodermis in the stem is not necessarily 

 preceded by any primary stage. The conditions under which the secondary 

 endodermis appears in the stem are reviewed with special reference to Rubus 

 Idccus, L., and Camellia japonica, L. 



16. Dr. W. EoBiNSON and Mr. H. Walkden. — Critical Observations 



on Crown Gall in Chrysantaemum frutescens. 



The work of Erwin Smith and others regarding Bacterium tumcfacivns as 

 the cause of crown gall is confirmed. Smith assumes, but does not claim to 

 have directly demonstrated, that the bacteria are present in the tumour cells. 

 From the present work it is concluded that B. tiimf'faricn.i is always present 

 in large numbers on the external surface, and sometimes on internal surfaces of 

 galls. We have further failed entirely to demonstrate the bacteria within the 

 tumour cells. All the effects are consistent with the action of increasing 

 numbers of B. tiiinefaricns, at first from the wounded surface, later from the 

 gall surface, from interstices of this or from internal surfaces. 



Smith's work on secondary tumours and tumour strands has been critically 

 repeated, galls similar in all respects and similarly distributed to the primary 

 and secondary galls figured by Smith having been obtained. Most, if not all, 

 of the secondary galls and tumour strands can be explained by the expansion 

 during rapid growth of meristematic tissues in the vicinity of the inoculated 

 wound rather than by the intrusive growth of tumour tissue in Smith's sense. 

 The similarities in this respect between crown gall and malignant tumours are 

 more apparent than real. 



17. Prof. E. EuGGLEs Gates. — Size-Inheritance in Plants and 



Aniiiials. 



It has been customary to interpret size-inheritance in terms of several 

 cumulative Mendelian factors. This method has been loosely used. Increased 

 variability in the F2 compared with the Fi has been regarded as sufficient 

 evidence for the view of multiple size-factors in inheritance. It has recently 

 been shown, however, that in animal hybrids certain non-inherited characters 

 exhibit gt-eater variability in F2 than in Fj. It may also be necessary to 

 distinguish between general size-inheritance and the size of repeated parts, such 

 as flowers on a plant. 



In crosses between (Enothera ruhricalyx with large flowers, and 0. biennis 

 (small flowers), the hybrids have been studied for five generations. The Fi 



