SCIENCE. 



489 



that knowledge which enables us to sort the things known 

 according to their true relations. On this ground we 

 call Haller the father of physiology, because, regardless 

 of existing theories, he brought together into a system all 

 that was ihen known by observation or experiment as to 

 the processes of the living body. But in the " Elementa 

 Physiologiae " we have rather that out of which science 

 springs than science itself. Science can hardly be said 

 to begin until we have by experiment acquired such a 

 knowledge of the relation between events and their ante- 

 cedents, between processes and their products, that in 

 our own sphere we are able to forecast the operations of 

 nature, even when they lie beyond the reach of direct ob- 

 servation. I would accordingly claim for physiology a 

 place in the sisterhood of the sciences, not because so 

 large a number of new facts have been brought to light, 

 but because she has in her measure acquired that gift of 

 prevision which has been long enjoyed by the higher 

 branches of natural philosophy. In illustration of tnis I 

 have, endeavored to show you that every step of the 

 laborious investigations undertaken during the last thirty 

 years as to the process of nutrition, has been inspired by 

 the provisions of J. R. Mayer, and that what we have 

 learnt with so much labor by experiments on animals is 

 but the realization of conceptions which existed two 

 hundred years ago in the mind ot Descartes as to the 

 mechanism of the nervous system. If I wanted another 

 example I might find it in the provisions of Dr. Thomas 

 Young as to the mechanism of the circulation, which for 

 thirty years were utterly disregarded, until, at the epoch 

 to which I have so often adverted, they received their full 

 justification from the experimental investigations of 

 Ludwig. 



But perhaps it will occur to some one that if physiol- 

 ogy founds her claim to be regarded as a science on 

 her power of anticipating the results of her own experi- 

 ments, it is unnecessary to make experiments at all. Al- 

 though this objection has been frequently heard lately 

 from certain persons who call themselves philosophers, 

 it is not very likely to be made seriously here. The 

 answer is, that it is contrary to experience. Although we 

 work in the certainty that every experimental result will 

 come out in accordance with great principles (such as the 

 principle that every plant or animal is both, as regards 

 form and function, the outcome of its past and present 

 conditions, and that in every vital process the same rela- 

 tions obtain between expenditure and product as hold out- 

 side of the organism), these principles do little more for 

 us thar indicate the direction in which we are to proceed. 

 The history of science teaches us that a general principle 

 is like a ripe seed, which may remain useless and inactive 

 for an indefinite period, until the conditions favorable to 

 its germination come into existence. Thus the conditions 

 for which the theory of animal automatism of Descartes 

 had to wait two centuries, were (1) the acquirement of an 

 adequate knowledge of the structure of the animal organ- 

 ism, and (2) the development of the sciences of physics 

 and chemistry; for at no earlier moment were these 

 sciences competent to furnish either the knowledge or the 

 methods necessary for its experimental realization ; and 

 for a reason precisely similar Young's theory of the circu- 

 lation was disregarded for thirty years. 



I trust that the examples I have placed before you to- 

 day may have been sufficient to show that the investiga- 

 tors who are now working with such earnestness in all 

 parts of the world for the advance of physiology, have be- 

 fore them a definite and well-understood purpose, that 

 purpose being to acquire an exact knowledge of the 

 chemical and physical processes of animal life, and of the 

 self-acting machinery by which they are regulated for the 

 general good of the organism. The more singly and 

 straightforwardly we direct our efforts to these ends, the 

 sooner we shall attain to the still higher purpose — the ef- 

 fectual application of our knowledge for the increase of 

 human happiness. 



The Science of Physiology has already afforded her aid 

 to the Art of Medicine in furnishing her with a vast store 

 of knowledge obtained by the experimental investigation 

 of the action of remedies and of the causes of diseases. 

 These investigations are now being carried on in all parts 

 of the world with great diligence, so that we may confi- 

 dently anticipate that during the next generation the pro- 

 gress of pathology will be as rapid as that of physiology 

 has been in the past, and that as time goes on the practice 

 of medicine will gradually come more and more under the 

 influence of scientific knowledge. That this change is 

 already in progress we have abundant evidence. We need 

 make no effort to hasten the process, for we may be quite 

 sure that, as soon as science is competent to dictate, art 

 will be ready to obey. 



METEORIC DUST. 



By Prof. Schuster. 



A committee of the British Association was appointed 

 for the double purpose of examiningthe observations hith- 

 erto recorded on the subject of meteoric dust and of dis- 

 cussing the possibility of future more systematic investi- 

 gations. With regard to the first point we note that in a 

 paper presented to the Royal Astronomical Society in 

 1879, Mr. Ranyard has given what appears to be a pretty 

 complete account of the known observations as to the 

 presence of meteoric dust in the atmosphere. It appears 

 that in the year 1852 Prof. Andrews found native iron 

 in the basalt of the Giant's Causeway. Nordenskjdld 

 found particles of iron which in all probability had a 

 cosmic origin in the snows of Finland and in the ice- 

 fields of the Arctic regions. Dr. T. L. Phipson, and more 

 recently Tissandier, found similar particles deposited by 

 the winds on plates exposed in different localities. 

 Finally, Mr. John Murray discovered magnetic particles 

 raised from deposits at the bottom of the sea by H. M. 

 S. Challenger. These articles were examined by Prof. 

 Alexander Herschel, who agreed with Mr. Murray in 

 ascribing a cosmic origin to them. For fuller details 

 and all references we must refer to Mr. Ranyard's 

 paper. There cannot be any doubt that magnetic dust, 

 which in all probability derives it origin from meteors, 

 has often been observed, and the question arises, in what 

 way we can increase our knowledge on these points to an 

 appreciable extent. A further series of occasional ob- 

 servations would in all probability lead to no result 01 

 great value, unless they were carried on for a great length 

 of time in suitable places. Meteoric dust, we know, does 

 fall, and observations ought if possible to be directed 

 rather towards an approximate estimate of the quantity 

 which falls within a given time. Difficulties very likely 

 will be found in the determination of the locality in which 

 the observations should be conducted. The place ought 

 to be sheltered as much as possible against any ordinary 

 dust not of meteoric origin. The lonely spots best 

 fitted for these observations are generally accessible to 

 occasional experiments only, and do not lend themselves 

 easily to a regular series of observations. Nevertheless 

 experiments continued for a few months at some ele- 

 vated spot in the Alps might lead to valuable results. 

 The Committee would like to draw attention to an in- 

 strument which is well fitted for such observations. It 

 was devised by Dr. Pierre Miquel for the purpose of ex- 

 amining', not the meteoric particles, but organic and or- 

 ganized matters floating about in the air. A description, 

 with illustrations, will be found in the Annuaire de Mont- 

 sour is for 1879. Two forms of the instrument are 

 given. In the first form, which is only adapted to per- 

 manent places of observations, an aspirator draws a 

 quantity of air through a fine hole. The air impinges on 

 a plate coated with glycerine, which retains all solid mat- 

 ter. By means of this instrument we may determine the 

 quantity of solid particles within a given volume of air. 



