ZOOLOGY. 343 



is but one histological element, the endoplast, which does nothing but 

 grow and vegetatively repeat itself; the other element, the periplastic 

 substance, being the subject of all the chemical and morphological 

 metamorphoses in consequence of which specific tissues arise. The 

 differences between the two kingdoms are, mainly : 1. That in the 

 plant the endoplast grows, and, as the primordial utricle, attains a 

 large comparative size: while in the animal the endoplast remains 

 small, the principal bulk of its tissues being formed by the periplastic 

 substance ; and, 2. In the nature of the chemical changes which take 

 place in the periplastic substance in each case. This distinction, how- 

 ever, does not always hold good, the Ascidians furnishing examples of 

 animals whose periplastic substance contains cellulose. The plant, 

 then, is an animal confined in a wooden case, and nature, like Sycorax, 

 holds thousands of " delicate Ariels " imprisoned within every oak. 

 She is jealous of letting us know this, and, among the higher and more 

 conspicuous forms of plants, reveals it only by such obscure manifesta- 

 tions as the shrinking of the sensitive plant, the sudden clasp of the 

 dionoea, or still more slightly, by the phenomena of the cyclosis. But 

 among the immense variety of creatures which belong to the invisible 

 world, she allows more liberty to her dryads ; and the protococci, the 

 volvox, and indeed all the Alga?, are, during one period of their exist- 

 ence, as active as animals of a like grade in the scale. True, they are 

 doomed eventually to shut themselves up within their wooden cages 

 and remain quiescent, but in this respect they are no worse off than 

 the polype, or the oyster even. In conclusion, the lecturer stated his 

 opinion that the cell-theory of Schwann consisted of two portions of 

 very unequal value, the one anatomical, the other physiological. So 

 far as it was based upon an ultimate analysis of living beings and was 

 an exhaustive expression of their anatomy, so far will it take its place 

 among the great advances in science. But its value is purely anatomi- 

 cal, and the attempts which have been made by its author, and br- 

 others, to base upon it some explanation of the physiological phe- 

 nomena of living beings by the assumption of cell-force, metabolic- 

 force, &c. &c., cannot be said to be much more philosophical than the 

 old notions of " the actions of the vessels," of which physiologists have 

 lately aken so much pains to rid themselves. The living body has 

 often, and justly, been called " the house we live in;" suppose that 

 one, ignorant of the mode in which a house is built, were to pull it to 

 pieces, and find it to be composed of bricks and mortar, would it be 

 very philosophical on his part to suppose that the house was built by 

 brick-force? But this is just what has been done with the human 

 body. We have broken it up into " cells," and now we account for 

 its genesis by cell-force. 



PISCICULTURE. 



In the last number of the Annual of Scientific Discovery, an account 

 was given of the recent experiments in France for extending the pro- 

 duction of fish ; experiments so satisfactory in their results in their 



30* 



