328 THE POPULAR SCIENCE MONTHLY. 



are of various and remarkable shapes, and are very interesting objects 

 when seen under the microscope. They are the representatives of the 

 calcareous plates which make up the hard shell of the sea-urchin. 



Unlike as are the crinoid, brittle-stars, star-fishes, sea-urchins, and 

 sea-cucumbers, in their form and general appearance, they are but 

 different expressions of one and the same fundamental idea. They are 

 all radiates, all possess calcareous plates though these are at their 

 minimum in the sea-cucumbers and are covered with spines, tuber- 

 cles, or a rough skin. They are all constructed according to a reigning 

 number, the principal parts being in fives, or some multiple of five. If 

 we imagine the sea-cucumber to be placed with its mouth downward 

 and the tentacles to be replaced with teeth, the long body to be 

 shortened upon itself so as to assume nearly the form of a hemisphere, 

 and the microscopic calcareous particles to be enlarged so that they 

 should touch one another, then we should have essentially the form 

 and structure of the sea-urchin. 



And if we imagine the sea-urchin with its segments spread out 

 into a star-like form, instead of being brought near together, each per- 

 forated segment taking half of the imperforate one, and at the same 

 time the spines to be reduced to tubercles and the plates to a net- 

 work, then we should have essentially the form of a starfish. 



Again, if the starfish had its body reduced to a well-defined disk, 

 and its arms starting out abruptly from this disk, we should have all the 

 most prominent features of the serpent-star. 



And if the serpent-star had its mouth placed upward, its arms mul- 

 tiplied by branching, and its ab-oral region elongated into a stem, we 

 should have the plant-like form of the crinoid. 



And so it is in all parts of the material world. Nature has but 

 comparatively few great types, but the forms included under these 

 types are almost endlessly varied. Unity in diversity is a great law 

 which prevails not only in the animal kingdom, but throughout the 

 whole realm of Nature. 







THE SCIENTIFIC STUDY OF HUMAN TESTIMONY. 



By GEORGE M. BEAED, M. D. 



III. 



OUTLINE of the Reconstructed Principles op Evidence 

 Even a qualified admission of the soundness of these views also 

 compels the admission that the reconstruction of the principles of evi- 

 dence is the crowning need of philosophy. 



Such reconstruction will not be made on the base of Pyrrhonism, or 

 the denial of the possibility of knowledge for knowledge is possible, 



