132 



THE AMERICAN MONTHLY 



[Jnlj, 



to study the microscopy of the details 

 of a minute animal. It has to be put 

 into hardening and water-absorbing 

 solutions, then to be cut with micro- 

 tomes, perhaps frozen in the first in- 

 stance, then to be put into other so- 

 lutions to be cleared and to have its 

 fat got rid of, and then it has to be 

 colored once, twice, or thrice, and 

 possibly to have some color dis- 

 charged. Finally it has to be mount- 

 ed in a medium. It is necessarily 

 somewhat deterrent for a modest mi- 

 croscopist to read the excessively 

 pronounced opinions of manipula- 

 tors about the nature of the structure 

 they discover in such complicated 

 and altered organic matter, and to 

 find that very contradictory opinions 

 are published by different investiga- 

 tors about the nature of identical 

 structures which have been different- 

 ly prepared. It appears to many an 

 amateur, who happens to investigate 

 structures by disturbing their natural 

 condition as little as possible, that 

 he is, as it were, out of the field. He 

 may find it necessary, even in exam- 

 ining the simplest section, to pay es- 

 pecial care to the illumination and 

 centering, and to the application of 

 particular powers. He is, of course, 

 conscious of inferiority, when he 

 knows that somebody merely puts a 

 chemically treated specimen under 

 an objective without the least care 

 about optics, and finds out, or thinks 

 he finds out, the truth. But there are 

 numerous opportunities for original 

 research still to be met with in the 

 structure of many of the commonest 

 invertebrates and plants. The study 

 of rocks is in its infancy, and there 

 are many very interesting physical 

 questions yet to be determined, and 

 which can only be settled microscopi- 

 cally. Recondite manipulation is not 

 much required in any of these re- 

 searches, but rather a good knowl- 

 edge of how to use the microscope as 

 an instrument. 



If in any case there are obstacles 

 to original research, it is always in- 

 teresting to follow the work of some 



distinguished investigator. It is very 

 rarely that a subject is treated ex- 

 haustively, and the sedulous yet can- 

 did critic, may solve truths which his 

 predecessor had not approached. 



In concluding this address, I can- 

 not avoid a special mention of the re- 

 cent death of a man whose genius 

 and careful microscopical work, es- 

 tablished an era in histology, and in- 

 fluenced that study of embryology 

 which must ever be the starting-point 

 of philosophical zoology and botany. 

 Theodore Schwann elaborated the 

 " cell theory " forty-three years ago, 

 and in the main it holds good at the 

 present day. He lived to see its value 

 appreciated by every zoologist, and 

 to be able to follow the researches 

 with improved lenses, and recognize 

 the entities which have no cell-wall. 

 Schwann investigated most success- 

 fully the nervous system, and his 

 name will ever remain associated with 

 it. He died at a ripe old age, having 

 led an industrious, simple, and most 

 useful life, and having lived to see 

 himself the recipient, on the occasion 

 of his jubilee, of distinguished hon- 

 ors on the part of the scientific world. 



EDITORIAL. 



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Bulletin of the Museum of 

 Comparative Zoology. — In our 

 March number, we noticed the first 

 five parts of the ninth volume of this 

 valuable publication, and now the 

 sixth, seventh and eight parts are 

 before us. It is proposed to issue, 

 in the " Memoirs " of the Museum, a 

 " selection from embryological mono- 

 graphs," which will give to the stu- 

 dent a more or less complete icono- 

 graphy of the embryology of each 

 important group of the animal king- 



