THE MICROSCOPE. 35 



judicious grouping of facts, the task becomes practicable even to 

 ordinary minds, and increasingly delightful as the hidden links in 

 the plan of " The Master Builder," which connect one form with 

 another, become gradually unfolded. Hence it is, that in all 

 modern works on natural history, so prominent a place is assigned 

 to the subject of classification. Authors in their preparation find 

 it requisite to carefully collate their facts ; taking first the simplest 

 and most rudimentary, they proceed thence to those whose 

 organisation becomes increasingly elaborate. 



I regret very much to find, even yet, so little appearance of 

 thought, on the part of many of our members, as to what they 

 shall put into our boxes, when the favoured opportunity comes for 

 so doing. It seems to me as if a glance were taken at the 

 Cabinet, and almost the first thing to meet the eye were put into 

 circulation. Or it may be that one of the last-mounted is con- 

 sidered, without any idea of connection with what may have gone 

 before, to sufiiciently meet the need of placing something in. 

 This would be natural at first. But could we not now aim at 

 something better ? There will always, with real workers, be 

 abundance of material to show, for the sake of its novelty. But 

 many of our slides can scarcely, without any approach to fairness, 

 come under such a heading ; though they may sometimes be 

 given m further elucidation of subjects already partially shown. 



In the list upon which these remarks are based,* it will be 

 seen that mineral or geological slides are placed first. Diatomacese, 

 as representing some of the humblest vegetable forms, and so largely 

 impregnated with mineral matter, follow. Next to these come, 

 cuticular appendages of higher plants, and starch as amongst 

 " Cell-contents." Then we have a Hydroid Zoophyte, and one of 

 the Molluscoid-Bryozoa ; which, with much external similarity of 

 form, yet possess, in rudimentary nervous system (with some at 

 any rate), an anal outlet, a decidedly higher type of organisation. 

 This juxta-position leads to reflection on the reason why forms 

 that seem so nearly related, require to be widely separated. As 

 examples of Insect-structures, appear the head of " Crane-fly " 

 and " Teeth of Blow-fly." Acari succeed these, and are followed, 

 lastly, by one of the dermal structures of a fish, with its remark- 

 able tooth-like structure ; which introduces us to the investigations, 

 into the true nature of teeth, with the surprising results obtained, 

 principally by Williamson and Huxley, of the essential identity of 

 dentinal and dorsal structures. 



* Names of Slides in the Box : — 



Elvanite. 



Crj'solite. 



Pinnularia viridis. 



Leaf of Vegetable Marrow. 



Starch, Cape-Coast Castle. 



Laomedea gelatinosa. 



Gemellaria loriculata. 



Head of Crane-fly. 



Teeth of Blow-fly. 



Gamasus from Humble-Bee. 



Mites. 



Spine and Scales of Dog-Fish. 



