" Nitragin " and the Nodules of Leguminous Plants. 167 



arrays, and not on the direct calculation of the correlation between 

 fecundities, a large percentage of which are probably fictitious (see 5). 



8. Parts II and III accordingly force us to the conclusion that fertility 

 is inherited in man and fecundity in the horse, and therefore probably 

 that both these characters are inherited in all types of life. It would 

 indeed be difficult to explain by evolution the great variety of values 

 these characters take in allied species, if this were not true. That 

 they are inherited according to the Galtonian rule seems to us very 

 probable but not demonstrated to certainty. It is a reasonable 

 hypothesis until more data are forthcoming. 



The memoir concludes with a discussion of the meaning of repro- 

 ductive selection for the problem of evolution and with sixteen correlation 

 tables, giving the dressed material on which our conclusions are based. 



" ' Nitragin ' and the Nodules of Leguminous Plants." By MARIA 

 DAWSON, B.Sc. (Lond. and Wales). Communicated by Pro- 

 fessor H. MARSHALL WARD, F.RS. Eeceived November 19, 

 Bead December 8, 1898. 



(Abstract.) 



A study of the nodules found upon the roots of leguminous plants 

 has led the author to an unhesitating confirmation of the parasitic 

 nature of both the filaments and the bacteroids contained in these 

 organs. The filaments, it was found, have no such constant relation 

 to the nucleus of the cells, as was represented by Beyerinck in 1888. 

 By plasmolysis of the root-hairs, the infection tube is shown to have 

 grown into the hair, and not to correspond with the primordial utricle 

 of the hair, a result which proves that Frank was mistaken in regarding 

 the tube as formed from the contents of the hair mingled with fungal 

 protoplasm. By staining with aniline blue and orseillin these tubes 

 and the filaments in the cells were shown to consist of strands of 

 straight rodlets, lying parallel to the longer axis of the filament, and 

 embedded in a colourless matrix. This matrix does not consist of 

 cellulose, chitin, or any form of slime. The swellings upon the 

 filaments occur at places where the rodlets have become heaped up, 

 and at such places the filaments eventually burst, liberating the 

 rodlets, whilst they themselves remain as pointed portions, directed 

 towards each other in the cells. After liberation from the filaments, 

 the rodlets become transformed into X, V, and Y-shaped bacteroids. 

 This variety of shape does not occur when these organisms are culti- 

 vated outside the plant on a solid medium, but in liquid pea extract 

 the change from straight rodlets to " bacteroids " occurs in a few days. 

 By cultivating these organisms in drop cultures under constant observa- 



