592 KECORD OF CUERENT RESEARCHES RELATING TO 



when the salts are absent from it? To resolve this question the 

 author, instead of using thin slices, experimented on pieces 1-2 and 

 5 mm. in thickness, and 5 mm. in length and width. The access of 

 air beincf thus hindered, it was, obviously, possible to see whether the 

 already observed diiferences were altogether to be ascribed to the 

 greater difficulty of respiration in salt-solution ; and these observa- 

 tions led him to the conclusion that, when less air penetrates, the 

 diiFerence between cells in pure water and in salt-solution is less 

 distinctly marked. The next thing was to subject the slices of beet- 

 root to an air-pump, before commencing the investigation ; pieces 

 thus treated showed a remarkable result, inasmuch as the balance was 

 after fifteen days in favour of the pieces immersed in the salt- 

 solution. 



Other results confirm a conclusion which may be thus formulated ; 

 the cells of the red beet-root, when air has free access to them, are 

 injm-iously aftected by salt-solutions, while when the air is removed 

 or is only present in small quantities these solutions have a sustaining 

 effect. The former point is the only one which the author at present 

 attempts to explain, and this explanation is found in the fact that 

 saline solutions absorb less gas than pure water, and that the co- 

 efficient of absorption decreases in proportion as the solutions become 

 more concentrated. 



"Law of Association." * — M. Edmond Perrier considers that the 

 oft-repeated objections to the theory of evolution leave the funda- 

 mental principles of that doctrine untouched. Having gone over the 

 various organisms from lowest to highest, seeking out, not the 

 differences, but the points of similarity between them, he believes he 

 has ascertained that a simple and very general law presided over their 

 formation, that they were derived from one another by a constant 

 process, and that he has succeeded in adding a few arguments to the 

 theory of the genealogical relationship of species. 



This law M. Perrier terms the " law of association." The process 

 by which it has produced the majority of organisms is the " transfor- 

 mation of societies into individuals." 



Ever since it was shown that every living being was composed of 

 microscopic corpuscles more or less resembling one another — that 

 similar corpuscles capable of leading an independent existence consti- ~ 

 tuted of themselves the simplest organisms — it has been thought that 

 the most highly organized animals and plants were comparable to 

 vast associations of distinct individuals, each represented by one of 

 these living corpuscles or cells. In the same organism the life of 

 each cell is so independent of that of its neighbours, that it is possible 

 to destroy one set of cells without affecting the others. Despite the 

 common bond which unites them, these cells, sometimes very dis- 

 similar, retain their individuality and perform their different functions 

 for the wellbeing of the whole community, like the various members 

 of a populous town. 



By " association," however, is not meant that the individuals band 



* ' Revue Scientifique,' Dec. 1«79, p. .'iSR. Soo ' Pop. Sci. Rov.,' iv. (1 SSO) p. .SO. 



