!>D() Dearborn, A Laboratory -Course in Physiology Based on Daphnia etc. 



every laboratory of chemistry, if we except a few always-present 

 implements such as a watch, a millimeter rule, and small and simple 

 glass-ware. To those of us who know the considerable expense of 

 most of the apparatus that we use, this factor will appeal. At any 

 rate, it puts this course within range of any school no matter how 

 simple or indigent or isolated. 



In similar manner, the life-material required is always 

 obtainable with great ease and with little or no expense, 

 summer or winter, and throughout the world. As is well known, 

 these animals have an almost Earth- wide distribution and are easily 

 gathered from pools and streams. If this be not convenient, a few 

 cents for postage brings most of these animalcules within easy 

 reach of such few schools as for special reasons might not care to 

 maintain the simple jar-aquaria for breeding them. They come in 

 such countless numbers so readily, that whoever made a business 

 of supplying them could not conscientiously, one would hope, charge 

 for them more than the smallest public class could easily pay. 

 Ease of maintenance of the animalcules is an advantage close 

 to that just mentioned. Instead of ill-smelling animal-rooms expen- 

 sive to maintain, containing unhappy large animals often both hard 

 and expensive to properly feed, the animalcules are kept in more 

 or less attractive glass aquaria that need contain no more than a 

 few liters of water each for use of large classes. Many of these 

 little animals maintain themselves year after year, Daphnia, for 

 example, not ,,running out" as long as one uses just ordinary in- 

 telligence in imitating a simple environment somewhere near that 

 which is natural to it. The infusoria of course, Stentor, Para- 

 meciuin, etc., can be readily developed at any time in two weeks 

 from old leaves and hay and similar commonplace material, every- 

 where and always at hand. 



No one with a quirkless brain can nowadays fail to justify 

 vivisection by competent scientists, but many, none the less, men 

 as well as women and children, savants as well as fools, dislike 

 to do this work, especially for purposes of routine class-instruction. 

 This repugnance to blood-shedding and mutilation is obviously a 

 necessary human feeling worthy to be cultivated rather than blunted. 

 (In the vivisection polemics one sees too seldom perhaps due credit 

 given us animal-experimentalists for the performance of disagreeable 

 death and mutilation on animals whom we of all men best appre- 

 ciate at their marvellous value and perfection). Strangely enough 

 the size of the animal is a factor in the determination of the 

 strength of this feeling of repugnance to mutilation found in all 

 normal human beings, while another of its determinants is com- 

 plexity. Men of culture who would hesitate to kill a mouse or to 

 drown a puppy have no such feelings ordinarily in regard to ants 



