6i4 THE POPULAR SCIENCE MONTHLY. 



plete series of illustrative specimens in all the departments of natural 

 history for educational museums. The writer had repeatedly seen and 

 admired collections of specimens from this establishment in colleges 

 and other institutions, but it was only recently that he was induced to 

 visit the former itself. It greatly exceeded his expectations, and sur- 

 prised him by its extent as well as delighted him from the excellence 

 and beauty of its collections. Many buildings were stored w4th ad- 

 mirably mounted and well-preserved vertebrates, snowy-white skele- 

 tons, a multitude of invertebrates, excellent models, fine collections of 

 minerals, and characteristic series of rocks and fossils. Even in the 

 great capitals of Europe nowhere did the writer see so great and excel- 

 lent a stock from which to furnish museums ; and it is in grateful 

 appreciation of the able and zealous services of Professor Ward, in 

 the interest of natural history, that the writer takes this opportunity 

 of recommending his establishment to those who desire to obtain col- 

 lections. In conclusion, to exemplify how much may be taught of 

 whole groups or orders from a few specimens, the writer presents the 

 following instance : He had in his possession a fragment of red coral, 

 the material so much used for ornament. Notwithstanding much ex- 

 planation, persons ordinarily appeared to him to be incredulous as to 

 its animal nature. In viewing Professor Ward's collections, he espied 

 among thousands of actual specimens a pair of beautiful models of the 

 red coral, one representing the object of natural size covered with the 

 soft flesh and exhibiting the tiny polyps ; the other representing a 

 magnified view, exhibiting a fragment of a stem with three polyps. 

 These were purchased for one dollar each, and are now placed together 

 with the natural coral fragment, and not only tell the whole story of 

 the animal at a glance, but tell that of the whole order to which it 

 belongs. Many such examples might be related, but one is enough. 



It is this careful attention of Professor Ward to the scientific and 

 educational import of his collections which has given his natural his- 

 tory establishment its high appreciation among the natui'alists and the 

 science teachers of our country. 



THE FOECE BEHIND NATUKE. 



By WILLIAM B. CAEPENTEE, M. D., F. E. S. 



SOME thirty years ago, I enjoyed opportunities of discussing with 

 John Stuart Mill (whose younger brother had been for twelve 

 months an inmate of my house) many questions of philosophy in 

 which we both felt the deepest interest. Among these was the Doc- 

 trine of Causation set forth in his recently published " System of 

 Logic" : "We may define the cause of a phenomenon to be the ante- 



