Feb. 6, 1890] 



NATURE 



323 



possibility of such a transmission, Prof. Vines should 

 interpret that in my favour, not to my discredit ; it is not 

 the business of an investigator to set forth a proposition, 

 which on the existing evidence he is compelled to believe, 

 as an infallible dogma. Prof. Vines finds my " statements 

 of opinion so fluctuating that it is difficult to determine 

 what [my] position exactly is," but he could have easily 

 discovered my meaning, if, instead of promiscuously con- 

 trasting the eight essays and the eight years of their pro- 

 duction, he had merely brought the last of them to the bar 

 of judgment. This essay is especially concerned with 

 " the supposed transmission of mutilations," and at its 

 conclusion my verdict on the state of the problem of 

 the inheritance of acquired characters is thus summar- 

 ised : — " The true decision as to the Lamarckian prin- 

 ciple [lies in] the explanation of the observed phenomena 

 of transformation. . . . If, as I believe, these phenomena 

 can be explained without the Lamarckian principle, we 

 have no right to assume a form of transmission of which 

 we cannot prove the existence. Only if it could be 

 shown that we cannot now or ever dispense with the 

 principle, should we be justified in accepting it." The 

 distinguished botanist De Vries has proved that certain 

 constituents of the cell-body, e.g. the chromatophores 

 of Alga;, pass directly from the maternal ovum to the 

 daughter-organism, while the male germ-cell generally 

 contains no chromatophores. Here it appears possible 

 that a transmission of somatogenic variation has oc- 

 curred ; in these lower plants, the separation between 

 somatic and reproductive cells is slight, and the body 

 of the ovum does not require a complete chemical and 

 physical alteration to become the body of the somatic 

 cell of the daughter. But how does this affect the ques- 

 tion whether, for instance, a pianoforte player can trans- 

 mit to his progeny that strength of his finger-muscles 

 which he has acquired by practice ? How does this 

 result of practice arrive at the germ-cells.'' In that lies 

 the real problem which those have to solve who maintain 

 that somatogenic characters are transmissible. 



It is proved by the observations of Boveri, quoted 

 above, that among animals the body of the ovum con- 

 tributes nothing to inheritance. If the transmission of 

 acquired characters should take place, it would have to 

 be by means of the nuclear matter of the germ-cells — in 

 fact, by the germ-plasm, and that not in its patent, but 

 in its latent condition. 



To renounce the principle of Lamarck is certainly not 

 the way to facilitate the explanation of the phenomena ; 

 but we require, not a mere formal explanation of the 

 origin of species of the most comfortable nature, but the 

 real and rightful explanation. We must attempt, there- 

 fore, to elucidate the phenomena without the aid of this 

 principle, and I believe myself to have made a beginning 

 m this direction. A short time ago I tried this in one of 

 those cases where one would least expect to be able to 

 dispense with the principle of modification by use — 

 namely, in the question of artistic endowment.^ I pro- 

 posed to myself the question whether the musical sense 

 of mankind could be conceived of as arising without a 

 heightening of the original acoustic faculty by use. But 

 even here I came to the conclusion that, not only do we 

 not need this principle, but that use has actually taken 

 no part in the development of the musical sense. 



A. Weismann. 



THE LIFE AND WORK OF G. A. HIRN. 



'T* HE three men who worked at the experimental deter- 

 -■- mination of the mechanical equivalent of heat and 

 at practical Thermodynamics have psssed away within 

 a few months of each other — Clausius, Joule, and now 

 Hirn. 



' "Gedanken uber Musik bei Thieren und bei Menschen," Deutsche 

 undschau, October 1889. 



They were much of the same age, and began their ex- 

 periments while young at almost the same time ; and 

 the practical agreement of the conclusions drawn from 

 their experimental results is our best guarantee of con- 

 fidence in the modem theory of Thermodynamics which 

 is built upon these results. 



Gustave Adolphe Hirn was born at Logelbach, in 

 Alsace, on August 21, 1815, and died on January 14 of 

 this year, a victim to the prevailing epidemic of influenza ; 

 but for this, we might have expected still further develop- 

 ments of his scientific theories, as he continued at work 

 on his favourite subjects to the last. 



Self-taught, so far as his scientific education was con- 

 cerned, he found himself, with his elder brother Ferdinand, 

 a manager of the works of Haussman, Jordan, and Co., 

 an establishment for the fabrication of indiennes., estab- 

 lished in 1772. Finding the machinery antiquated and 

 worn out, Hirn, in setting to work to makethebest of it, was 

 really better placed for theorizing and experimentalizing 

 than if he had charge of modern works in first-rate order. 

 The different parts of the works being at a distance 

 from each other, his brother Ferdinand brought out his 

 system of cable transmission of power ; and it was 

 Gustave who pointed out theoretically the advantage of a 

 thin light cable run at a high speed. 



Hirn also turned his attention to the important economic 

 question of the lubrication of machinery, and upset the 

 previous prejudice against the use of mineral oil for this 

 purpose. He also demonstrated experimentally that, while 

 the old laws of friction enunciated by Morin were suffi- 

 ciently accurate for the contact of one dry metal against 

 another, these laws are powerfully modified when the 

 surfaces are well lubricated, as with machinery. Now the 

 friction varies as the square root of the pressure, and as 

 the surface and the velocity ; so that the theory falls in 

 with that of the viscous flow of liquids. These laws have 

 received confirmation of recent years by the experiments 

 carried out under the auspices of the Institution of 

 Mechanical Engineers. 



But it is chiefly for his experiments on a large scale on 

 the steam-engines under his charge that Hirn is best 

 known, and from his varied methods of determining the 

 mechanical equivalent of heat by the friction of metals 

 on metal or water, and finally from observation of the 

 amount of heat consumed by the steam-engine, when 

 every source of gain or loss is carefully followed up. 



With this object he investigated experimentally the 

 separate effects of conduction, of jacketing, of initial 

 condensation in the cylinder, and of its prevention by 

 superheating. 



If we watch the performance of a modern marine triple- 

 expansion engine, we notice that the high-pressure 

 cylinder appears choked with water from initial condensa- 

 tion, while the intermediate and low-pressure cylinders 

 work comparatively dry. It was considered in the early 

 days of compound engines that this initial condensation 

 was a source of great loss, and superheating was intro- 

 duced to minimize it. But the superheated steam ruined 

 the packings, and dried up the lubricant, so that the 

 superheater was found practically to do more harm than 

 good. A characteristic story is told of John Elder, the 

 pioneer of compounding in modern marine engines, too 

 long to insert here, which bears on this point. 



Nowadays this initial condensation is looked upon as 

 inevitable, and as not really so uneconomical as the 

 books make out, when attendant advantages are con- 

 sidered ; but to the theorist such as Hirn this condensa- 

 tion was something to be avoided at any cost, and he 

 worked hard to make its prevention feasible. 



Hirn was a man of varied reading, taste, and pursuits, 

 and he worked into his treatises on his favourite subject 

 of Thermodynamics a good deal of speculative meta- 

 physics, which make his books rather curious reading 

 sometimes to modern tastes, and we must go back to the 



