September 21, 1883.] 



SCIENCE. 



401 



wlio found theories on experiments, and then verify 

 the truth of their hypotlie:ses by renewed investiga- 

 tions. It is beyond question, that the labors of 

 Alendelejeff and Meyer are the point of departure 

 of a rational classitieation of matter, and that they 

 have been a fertile source of useful chemical dis- 

 coveries. 



Professor nermann Fol of the university of 

 Geneva described his studies on animal individuality. 

 In the lower animals, individuality is a dififerent 

 thing from what it is in the higher, such as tlie mam- 

 mifers. But this law of individuality among the 

 vertebrates is not without exception; and we all 

 know the wonder which is excited by the sight of 

 creatures with some member double, such as are 

 often exhibited at shows, or may be seen in mu- 

 setmis. 



For a long time we have tried to explain the origin 

 of these anomalies. Two theories have been pro- 

 posed, — that of the creation of two distinct beings, 

 and that of the partial division of one primitive 

 simple. Neither of these theories quite accounts 

 for the phenomena observed. The new and essential 

 fact which Mr. Fol presented comes under the general 

 law, that in these abnormal cases two heads always 

 appear in the egg at the commencement of its devel- 

 opment. The body forma immediately behind; and 

 these two trunks, coming together, are so perfectly 

 united that the two primitive heads are very near 

 each other at the outset. In the first place, then, 

 only the higher part of the body is duplicated in 

 these montrosities; yet these two parts may become 

 completely separated, resulting in twins, which so 

 closely resemble each other that even the parents 

 find difficulty in distinguishing them. 



Mr. Fol has investigated the cause' of the appear- 

 ance of two embryos in one egg, by a very neat 

 method. He asphyxiated the eggs of Echinus by 

 immersion in Seltzer water (containing pure carbonic 

 acid) ; and he ascertained that in this unhealthy con- 

 dition, maintained f(ir a moment, two germs at the 

 instant of passage into life could simultaneously 

 have birth. 



Our individuality is one of our most cherished 

 ideas. The great philosophers Descartes, Kant, etc., 

 <lid not investigate even the possibility of a multiple 

 individuality: it is interesting to observe the flexi- 

 bility of that idea under the disturbing influence of 

 special conditions of the origin of life. 



Jlr. Fol exhibited plates representing different 

 kinds of montrosities: two heads and one body, a 

 little body projecting from the eye of a child other- 

 wise relatively well formed, etc. 



Professor Herzen of Lausanne, in closing the 

 session, invited all the doctors present to observe 

 an exceedingly interesting case, — that of a man who 

 was on the point of dying from hunger, the results 

 of strangling, when M. de C^renville of Lausanne 

 began his experiments. This skilful surgeon ar- 

 ranged a stomachic fistula by which the man ate. 

 He was regularly supplied with food, recovered his 

 strength, and rapidly improved. Mr. Herzen took 

 care of this man at his laboratory, and studied the 



phenomena of digestion according to the process 

 wliii-h recalls the well-known Canadian case of M. 

 de Beaumont. 



The next morning the association met in sections 

 in different halls. Unfortunately the gift of omni- 

 presence was not given to man, and the members of 

 one section could with difficulty glean here and there 

 any knowledge of what was taking place in the 

 neighboring halls. Besides it would take a volume 

 to contain such a quantity of material, of which a 

 resum^ will appear in the September number of the 

 Archives dea sciences phyxiques et naturelles. 



The following account treats only of the subjects 

 t.-ikcn tip in the single section of physics. 



Professor Clausius of Berne was elected, by ac- 

 clamation, president; and Mr. Weber of Neuchitel, 

 secretary. Mr. F. A. Forel submitted a very in- 

 teresting paper on the variations of temperature 

 which the Swiss lakes undergo, from summer to 

 winter, and from morning to night. It seems that 

 in an average year the variatiot\s of temperature in 

 the year are scarcely noticeable at a greater depth 

 than 00 to 80 metres; above that, the surface of the 

 water is for these lakes between 4° and 5.4°, the 

 highest temperature corresponding to that of Lake 

 Geneva. The variations are fell at a mean depth of 

 ten metres. 



After a lively discussion of the manner in which 

 the currents of water influenced by these variations 

 of temperature are set in motion, Prof. Charles 

 Soret of the university of Geneva submitted the 

 results obtained with his new apparatus, the refrac- 

 tometer. This first set of experiments dealt especially 

 with the crystals of the alum-series whose radical is 

 an alkaline metal. This very clear communication 

 was especially remarkable for the skill with which 

 the young professor set forth his subject with a great 

 number of new facts in a comparatively short time. 

 He was followed by his father, Prof. L. Sorel, 

 who presented a paper for Mr. L. E. Sarasin, and 

 demonstrated by figures and curves the vahies of 

 the index of refraction of fluor spar, a crystal, which, 

 since the important works of Corini and L. Soret, 

 has taken so important a place in the construction 

 of the achromatic lenses of spectroscopes. This 

 paper was marked by extreme precision. 



Mr. L. Soret presented a communication to the 

 section of chemistry, belonging in great part to the 

 section of physics. He set forth how the absorption 

 bands seen in the spectra of solutions of albuminoid 

 substances could be used in ascertaining the chemical 

 nature of these solutions. These absorption bands 

 are found especially in the ultra-violet; and, thanks 

 to the fluorescent eye-piece invented by the speaker, 

 their presence renders an analysis very rapid and 

 simple. 



Professor Clausius of Bonn gave us a lesson in 

 mechanical electricity: he considered the problem of 

 the production of electric currents by mechanical 

 means. All the knowledge of this scholar, this en- 

 thusiastic and ingenious investigator, was necessary 

 to obtain the final solution of so complicated a prob- 

 lem. The paper was heartily applauded. 



