LITERARY NOTICES. 



755 



ber of specimens of plants and animals, se- 

 lected by Mr. Calkins to represent the more 

 interesting groups of organic forms, are 

 printed in colors upon cards for convenience 

 of handling in the class-room. It needs not 

 to be said that these illustrations are beau- 

 tifully executed, and cannot fail to prove in 

 a high degree attractive to children. That 

 they have been executed with care and cor- 

 rectness, under the vigilant direction of Mr. 

 Calkins, there can be no doubt. As to 

 their utility in education, that will depend 

 entirely upon the teacher and the policy of 

 the school. If employed as guides to the 

 study of real objects, they cannot fail to be 

 helpful ; but, if subordinated to the usual 

 system of study, and accepted in place of 

 the things they represent, they will have 

 simply the value of excellent pictures, and 

 will add to the already immense mass of 

 hindrances and stumbling-blocks which the 

 schools interpose between the minds of 

 children and the objects of Nature. 



The Stone Age, Past and Present, by 

 E. B. Tylor ; and Theory of Nervous 

 Ether, by Dr. Richardson, F. R. S. 

 Boston : Estes & Lauriat. Price, 25 

 cents. 



This is No. 9 of "Half-Hour Recrea- 

 tions in Popular Science." The first paper 

 is a popular account of the stone age, or, as 

 the author puts it, " of that period in the 

 history of mankind during which stone was 

 habitually used as a material for weapons 

 and tools." This period he divides into two 

 parts, the first of which he calls the Un- 

 ground Stone Age, when the implements em- 

 ployed were merely chipped out, and used 

 in a comparatively rough and imperfect 

 shape. Such implements are found in 

 greatest abundance in the Drift or Quater- 

 nary Deposits, and in the early bone-caves, 

 and consist largely of chipped flints, appar- 

 ently designed for spear -heads, arrow- 

 heads, scrapers, knives, etc. The second 

 or later division of the period above re- 

 ferred to — the Ground Stone Age — is char- 

 acterized by the employment of ground and 

 often polished instruments of stone, much 

 more perfect than the chipped forms, and 

 therefore denoting a higher stage of human 

 progress. Stone implements are found in 

 nearly every part of the world, and, what- 



ever their source, show a remarkable uni- 

 formity of pattern. This latter feature the 

 author accounts for partly on the principle 

 that man does the same thing under the 

 same circumstances, and partly on the be- 

 lief that the art was derived by one race 

 from another. The evidences of the stone 

 age, brought to light in the countries hith- 

 erto explored, take up the remainder of 

 the paper. Any one wishing a general idea 

 of what is at present known on this inter- 

 esting subject, will be well repaid by a pe- 

 rusal of this essay. 



The theory of a nervous ether we will 

 give in the author's own words : " The idea 

 attempted to be conveyed by the theory 

 is, that between the molecules of the mat- 

 ter, solid or fluid, of which the nervous or- 

 ganism, and indeed of which all the organic 

 parts of the body are composed, there exists 

 a refined, subtile medium, vaporous or gase- 

 ous, which holds the molecules in a condi- 

 tion for motion upon each other, and for 

 arrangement and rearrangement of form ; 

 a medium by and through which all motion 

 is conveyed ; by and through which the one 

 organ or part of the body is held in com- 

 munion with the other parts, and by and 

 through which the outer living world com- 

 municates with the living man — a medium 

 which, being present, enables the phenom- 

 ena of life to be demonstrated, and which, 

 being universally absent, leaves the body 

 actually dead ; in such condition, i. e., that 

 it cannot, by any phenomenon of motion, 

 prove itself to be alive." The paper is de- 

 voted to an elucidation of this theory. 



Insects of the Garden : Their Habits, etc. 

 By A. S. Packard, Jr. Boston : Estes 

 & Lauriat. Price, 25 cents. 



This is the first part of a volume from 

 the pen of Prof. Packard, entitled "Half- 

 Hours with Insects," to be issued in twelve 

 parts, of about 36 pages each, by the above 

 house. Beginning with some general con- 

 siderations on the relations of living ob- 

 jects to one another, the ' author passes 

 thence to the subject of agriculture, and 

 the manner in which its interests are affect- 

 ed by the incursions of insects. Numerous 

 instances are given of their terrible de- 

 structiveness to crops, which, though appar- 

 ently insignificant when estimated, say, for 



