818 BIOLOGICAL TRAINING AND STUDIES. 



compound body. I think of the two it is better that the aquarium 

 should be horizontal rather than the microscope; and those who 

 think with me in this matter can nevertheless combine for them- 

 selves the advantages of the horizontal position of the instrument 

 with those of the horizontal position of the objects observed by 

 modifying the eyepiece in the way figured by Quekett (p. 381, 

 fig. 266). It would be a long task to enumerate fully all the 

 scientific lessons which may be gathered, first, and all the educa- 

 tional agencies, secondly, which may be set and kept in move- 

 ment by a person who possesses himself of this simple apparatus. 

 The mutual interdependence of the animal and vegetable kingdoms, 

 their solidarite as the French have called it, and as the Germans 

 have called it too, copying herein the French, is one of the first 

 lessons the observer has forced upon him ; the influence of 

 physical and chemical agencies upon the growth and development 

 of living beings he soon finds strikingly illustrated ; the mysterious 

 process of development itself is readily observable in the eggs of 

 the common water-snails and in those of freshwater fish, so that 

 the way in which the various organs and systems of organs are 

 chiselled out, built up, and finally packed together and stratified 

 can be taken note of in these yet transparent representatives of 

 these great sub-kingdoms which all the while are undisturbed and 

 at peace : and all these points of large interest are but a few of 

 many which these small means will enable any one to master for 

 himself in the concrete actuality, and thoroughly. The necessity 

 for carefulness and truthfulness in recording what is seen, the 

 necessity for keeping in such records what one observes quite dis- 

 tinct from what one infers, the necessity for patience and punctu- 

 ality, are lessons which, from having a moral factor as well as a 

 scientific one in their composition, I may specify as belonging 

 to the educational lessons which may be gathered from such a 

 course of study. 



I have been speaking of the microscope as an instrument of 

 education, and I wish before leaving the subject to utter one caution 

 as to its use when this particular object of education is in view. 

 If a subject is to act educationally, it must be understood 

 thoroughly; and if a subject is to be understood thoroughly, it 

 must form one segment or stretch in a continuous chain of known 

 facts. 'ApKriov airb tS>v yz^cop^/xcor, said one of the greatest of 



