ESSAY-REVIEWS 95 



although it crystallises in the cubic system. Each unit cube of 

 the structure contains in the one case half a molecule of KC1 and 

 in the other case a whole molecule of NH,C1." There are other 

 cases also in which workers in allied fields must supply for 

 themselves the due co-ordination of the old and the new, a 

 monopoly of attention being, naturally, lavished upon the latter. 

 But this, perhaps, is inevitable in a subject with so many points 

 of contact with others. It is probable that the work both on its 

 systematic and theoretical side is only in its beginnings, and the 

 book will undoubtedly do much to stimulate the most profitable 

 of all scientific work, the correlation of the various branches of 

 knowledge. 



THE ORGANISM AS A THERMODYNAMIC MECHANISM, by 



Hugh Elliot : on 



1. Is the Organism a Thermodynamic Mechanism? Article by Dr. James 



Johnstone in Science Progress, April 1915. 



2. The Mechanistic Principle and the non-Mechanical, by Paul Carus. 



[Pp. 125.] (Chicago: The Open Court Publishing Company, 1913, 

 price 4s. net.) 



3. The Principle of Relativity, by Paul Carus. [Pp. 105.] (Chicago : 



The Open Court Publishing Company, 19 13, price 4s. net.) 



4. The Analysis of Sensations, by Dr. Ernst Mach. Translated from the 



First German Edition by C. M. Williams. [Pp. xiv + 380.] 

 (Chicago and London : The Open Court Publishing Company, 19 14, 

 price 6s. 6d. net.) 



5. The Mirror of Perception, by Leonard Hall, M.A. [Pp. 129.] 



(London: Love & Malcomson, 19 14.) 



An interesting feature, which constantly recurs in the history 

 of science, is the gradual progress of unpopular doctrines 

 against a solid body of hostile superstition and ignorance. 

 Science is unpopular, partly because it demands severe mental 

 concentration, and partly because its conclusions and principles 

 are often at variance with those which the public desire to 

 believe, and which, therefore, they intend to go on believing, 

 notwithstanding any evidence that may be presented to them 

 in a contrary sense. Among the doctrines which are thus 

 exposed to public animosity is the theory that an organism — 

 animal or plant — is a machine, all the processes of which are 

 controlled and determined by physical and chemical forces 



