Jun E( i8 9 6. VERWORN'S GENERAL PHYSIOLOGY. 4°5 



various physiological and psychological theories, including an 

 excursus into metaphysics, he comes to the sane conclusion of 

 Johannes Miiller, that there is no special physiological method, but 

 that all methods are right if they lead towards the goal. The goal is 

 investigation of life ; and chemistry and physics, anatomy and 

 embryology, zoology and botany, mathematics and metaphysics, all 

 must be pressed into the service. 



The second chapter, 84 pages in length, treats of the living 

 material. Noting first that living material occurs discretely in indi- 

 vidual masses, Dr. Venvorn discusses the conception of individuality. 

 He dismisses, of course, the old view that indivisibility was the 

 criterion of an individual, and comes to the definition that an organic 

 individual is a single mass of living material, in a formation that is 

 capable of maintaining independent existence. He discusses the 

 various categories of individuality from cells to states, pointing out 

 that the higher individuals are composed of colonies of the next 

 lower grade, and distinguishing, although not with the felicity of 

 Professor Patrick Geddes (in the Encyclopaedia Britannica), between 

 morphological and physiological individuality. He discusses 

 Altmann's granular theory, but accepts the criticism that Altmann 

 included among " bioblasts " structures of quite different morpho- 

 logical and physiological value. He regards the cell as the vital 

 elementary organism, and proceeds to discuss its various forms and 

 its organs, such as the nucleus and the centrosome, which he takes to 

 be a specialised part of the nucleus, sometimes with an independent 

 existence. Then follows an account of the morphology of the cell, 

 and of the plastids, such as starch granules, that may be found in it, 

 and of the physical structure of protoplasm. In the latter connection 

 he follows Butschli (see Natural Science, vol. ii., p. 31) in the main. 

 Then comes a most careful account of the chemistry of protoplasm, 

 and an ingenious summary of the differences between organic and 

 inorganic matter, a comparison in which, however, we think he is 

 inclined to insist more upon the differences than upon the identities 

 between the two. His final summary, however, is sufficiently 

 mechanical to disturb the most ardent vitalist. " The process of 

 life," he says, " consists in the metabolism of albumens." 



The third chapter, extending to 130 pages, treats of elementary 

 vital phenomena. The first section of this deals with metabolism, 

 and the author gives a good account of the different food-materials 

 and methods of absorption found among plants and animals. He 

 makes the curious slip of stating that plants absorb their gaseous 

 food through the stomata ; it has been shown clearly by many 

 experiments that the main function of stomata is regulation of the 

 transpiration of aqueous vapour ; carbonic acid and oxygen are 

 absorbed through the general surface of the leaf. He then treats of 

 anabolism, dealing perhaps rather superficially with the stages 

 between food-material and proteid ; and of katabolism, where his 



