ZOOLOGY AND BOTANY, MIOKOSCOPY, ETC. 



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mankind is not grateful enough for their toil. Experimental researches, 

 like those which Mr. Crookes explained last night at the Eoyal Institution, 

 force the mind to consider matter in its ultimate and minutest forms as 

 analysed by the electric spark and the spectroscope, in atmospheres 

 millionths of our common air in tenuity ; and they are not less wonderful 

 than the contemplation of worlds thousands upon thousands of times larger 

 than our own. Our astronomers are engaged at present in photographing 

 the face of the midnight heavens, having discovered that the film which 

 they expose to the sky is far more sensitive to light than the keenest human 

 eye, and more than one observatory is thus registering distant and minute 

 stars previously unknown. The stellar universe has been by such means 

 perceived to be more crowded with life and glory than had been realized ; 

 and night after night the astronomer's camera in this silent way prints off 

 accurate pictures of seen and unseen immeasurably distant worlds. Mean- 

 while, coming from the realms of matter to the sphere of life, the micro- 

 scopists are quite as busy as the telescopists, and the results which they 

 achieve, although drawn from regions that escape us by minuteness, often 

 shed new rays of truth over those problems of living nature which bafifie 

 us by their vastness. The Eev. Dr. Dallinger, President of the Eoyal 

 Microscopical Society, delivered an address last week which well illustrates 

 this view, while it gives an example of the admirable and unceasing devotion 

 shown by our best scientific men. After dwelling on certain recent im- 

 provements in the construction of lenses, the President, on the occasion 

 referred to, proceeded to describe a series of experiments which he has con- 

 ducted for nearly ten patient and faithful years. Long ago Darwin ex- 

 pressed the opinion that if we would actually observe and demonstrate the 

 manner in which living creatures adapt themselves, by inward and outward 

 modifications, to changed circumstances, and so produce what are called new 

 species, it must be by watching the lowest and least visible organisms. To 

 euch a task Dr. Dallinger set himself. His project was to place and keep 

 under his lens several varieties of those minute monads which are inces- 

 santly multiplying by fissure or division, and which are nearly at the bottom 

 of animated nature. The generations of these creatures succeed each other 

 about every four minutes ; so that, in the course of an hour, we can view 

 the passage of fourteen or fifteen generations, which would answer to some- 

 thing like four hundred and fifty years of human history, while a day of 

 monadic existence would represent more than ten thousand of our years. 

 These monads live in water, and by connecting the drop that serves them 

 for a habitable and roomy ocean with the ingenious apparatus of Prof. 

 Schafer the temperature of this drop can be either kept constant or raised 

 very slowly and with absolutely steady precision. Here, therefore, were 

 the conditions requisite for gradually altering the climate in which these 

 monads throve ; and if it could be proved that such tiny infusoria could 

 indeed be slowly accustomed to changes greater than would be suffered by 

 animals removed from the Equator to the Pole, then bright and trustworthy 

 light would be cast on the modifications of life which we see arrived at on 

 the earth, and Darwin's great law would be largely removed from theory to 

 recorded fact. To carry out so very delicate an investigation, however, it 

 would have to be prolonged for months and even years, in order to imitate 

 the immense deliberation with which Nature herself accomplishes every 

 substantial change in her highest productions. Night and day, winter and 

 summer, the patient gaze must be kept fixed on those merest specks of 

 silvery life which had to be nursed into new conditions of existence. The 

 slightest accident to the apparatus might in one moment render the whole 

 experiment void, and leave the drop of water as lifeless as these islands 



