Proceedings of the Society. xxix. 



Journals. The Th-ory of the Au hor appeared extremely inge- 

 nious in its explanation, and retsjoable even to scienlifie men 

 such a; Dr. Murray; and other authorities equally respectable 

 may also be adduced in support of tliis snme Theory. 



Ti Indeed the Society has just received recent works by Lieb g 

 and Dr. Gregory of Eiioburgh, and these illustrious Authors, in 

 explaining the cause and nature of the potato disease, reason ia 

 their case in a manner quite analogous to that in which Mr. 

 Bojer, on hie part, argues to accouni for the disease in the canes. 



Liebig goes still farther and, ^s a general position, he 

 ascribes to one an \ tlie same cause, both such epidemical af- 

 fections as have their seat in the organs of respiration, and the 

 disease which existed throufihjul the whole of Europe among 

 the (.uiatoes. 



» The cause of the disease, he says, is the same which, in 

 1 sprma and aulunm, excites infl jenza ; that is, the disease is 

 » the effect of the temperature and hygromelric state of the 

 i> atmosphere, by which, in consequence of the disturbance of 

 » ih ■ normal transpiration, a ch^ck is suddenly, or for a lon- 

 » s;d«:!rable time, givento the motion of the fluids, which is one 

 » chief rondilion of life, and which ihus becomes insnifi^ient 

 1 lor the purposes of h Tilth, or even hurtful to tha individual. » 



I' If we reflect, Liebig adds, that a plant, in order to protect 



> itself from external causes of disturbance, or to seek the food 



> wnich It requires, cannot change its place; that its normal 



* vital functions depend on the simultaneous and combined 



> action of water, of the soil, of the external temperature, and 



* of the hygtometric .state of the atmosphere ; that is, on lour 

 cviernai circumstances ; it is easy to comprehend the dis- 



» turbance oi functions which must occur in the organism in 

 » ce-nscquence of any change in the muual relations of so many 



> combined agencies. The state of a plant is a sure indication 



> of equilibrium or of misproportion in the external conditions 

 I of its life ; and the dexterity of the accomplished gardener 



> cou&is:sex.ictly in this, thai be knows andean establish the 



