180 



PHILOSOPHICAL NOTES ON 



different plants, contain it. Are all these furnished vnth nodules 

 on their roots ? 



Xow is there no other way of accounting for the tuhercles on 

 the roots of the Leguminiferoe, except through these micro- 

 organisms ? Supposing these micro-organisms to exist at all 

 in the tubercles, may it not be possible for the latter to be 

 otherwise accounted for, and that these low organisms take up 

 their abode there, if it be proved that they do not exist anyivhere 

 else in the plant. 



We should not, ho^vever, be startled by this statement, for 

 recently Dr. Cunningham has told us that the tickling of an 

 insect causes the ovule of the Ficus to develop parthenogenetically. 



I find that in Lathyrus tuberosus the roots bear largish 

 tubers, from one to tAvo inches long,* and are evidently enlarge- 

 ments of the base of root -fibrils (Fig. 50). I think it more 

 natural to conclude that the minute tubercles on other legumini- 

 ferae may be atrophied tubers. 



Fig. 50. Tubers on roots oi Lathyrus tuberosus (" Syme's Brit. Bot.," pi. 401). 



Fig. 51 . Tubers on roots of Lathyrus macrorhizus (" Syme's Brit. Bot.," pi. 406). 



* The tubers of this vetchling might possibly be enlarged and improved, 

 and so become useful for food. 



