PHYSIOLOGICAL BOTANY. 199 



in its Application to Physiology and Pathology) is still 

 an excellent one. It shows us how the proportion of the 

 constituents of the fluids, and of the solids of the animal 

 body, may be deduced from the proportions of the con- 

 stituents of the nutritive matters, This is certainly the 

 first step towards explaining the nutrition of the animal 

 body and its secretions ; but it is only the first step, and 

 we are ignorant of the decomposing and the combining 

 forces. They appear to belong to physical rather than 

 vital forces ; and even when we have ascertained these, 

 the ultimate means by which these forces are set in action 

 remain to be determined. And for the physician, the 

 principal point is to increase the activity of these forces ; 

 or when it is too great, to diminish it. We must agree 

 with Liebig, nay, we might even censure with his violence, 

 when we see how many physiologists misapply the word 

 life ; but this blame does not attach to all physiologists, 

 when they used the term vital force correctly, i. e. when 

 they apply it to those cases in which chemical forces cease 

 to act in their natural manner. It is very necessary to 

 advance by means of physics and chemistry as far as 

 possible, but we must not trust more to these two 

 sciences than they are capable of effecting. 



Gaudichaud has come forward with great decision 

 against Mirbel in the Academy of Sciences at Paris. 

 Offended by some expressions which Mirbel made use of 

 in his ' Memoir upon the Structure of the Stem of the 

 Date-palm/ and which Gaudichaud correctly considered 

 as directed against him, immediately after the reading of 

 the memoir, he briefly protested against it, and declared 

 Mirbel' s system to be incorrect. There also appeared 

 soon after, in the year 1843, two memoirs justifying his 

 protest. They have been spoken of in the 'Annual 

 Report ' for 1842-3, as have also his EechercJies generates 

 sur T Organographie, &c. des Plantes in the ^Annual 

 Report ' for 1841. In the ' Comptes Rendus ' for 1844, 

 we now have the third and fourth protests against Mirbel 

 (I, pp. 597 and 899). He has not yielded. In 1844 



