Carbon Chemistry -with Vital Phenomena. 355 



uiucic acid, and represent its connexions by a diagram, and we 

 find a large number of very important correlations implicated, 

 thus: — 



Cellulose. 



Gums. 



Mucic acid. 



(Dichloro-muconic acid) (Pyromucic acid). 

 Adipic acid. Furfuraldehyde. 



Cork tissues. Fats. Lignin. Astringents. 



A quantification of these relationships, and a multiplication 

 of investigations according to such a priori correlations, could 

 not fail to establish important truths concerning the genetic 

 connexions of the carbon compounds. 



A further illustration of the want of correlation of chemical 

 with biological investigation is to be found in the prevalence 

 of empirical and statistical analyses of plant-substances in 

 agricultural work. To a certain extent it is evident that 

 statistical must prevail over molecular methods where the 

 complex substances and mixtures of substances which are 

 elaborated in the plant world are the subject of inquiry ; but we 

 contend that these may be ordered on a much more rational 

 basis than is at present adopted. 



The somewhat arbitrary choice of reagents, such as Schulze's 

 for the isolation of cellulose, of boiling dilute sulphuric acid 

 and alkali successively applied to plant-substances for the 

 determination of their so-called crude fibre, the dismissal of 

 whole groups of bodies as " extractive matters " or as " in- 

 crusting and intercellular substances," and the general absence 

 of the recognition of the genetic connexion of these substances 

 with those from which they are separated — in fine, the almost 

 exclusive choice of the indirect and statistical before direct 

 methods of observation, argues a certain misapplication of 

 time and capability, and sufficiently accounts for the indiffer- 

 ent, if not critical, attitude of the greater number of chemists 

 towards Biochemical science. We may cite the literature on 

 the subject of chlorophyll, the proteids, the carbohydrates, 

 including cellulose, the group of pectous substances, and, until 

 the recent work of 0' Sullivan and Brown and Heron, starch. A 

 more special illustration is to be found in the work of Meissner 

 and Shephard on the origin of hippuric acid in the urine of 

 Herbivora. In order to identify the parent substance — that 

 constituent of grasses which could yield the necessary benzoic 



