APPENDIX TO THE BIOGPxAPIIIC NOTICE OF PELTIER-SCIENTIFIC 



NOTICE. 



[TRANSLATED FOR THE SMITHSONIAN INSTITUTION, BY C. A. ALEXANDER.*] 



I. — MiCKOSCOPIC RESEAKCHES. 



We owe to Peltier observations on certain new microscopic animals. We 

 will cite among others his observations on a vorticella which, by its form, closely 

 approximates to that which i\Inller has called citrine, and, in its interior consti- 

 tution, resembles the vorticella or umbel of Roesel. We will also advert to his 

 observations on a new species of floscularia. We shall not, however, dwell on 

 this class of researches. Peltier, in fact, had never devoted himself to the use 

 of the microscope in order to discover new individuals ; microscopy was for him 

 but a means of study for arriving' at a more thorough knowledge of physiology. 



Effects of inanition on the infusoria. — Microscopic animals have, in general, 

 a very simple structure ; still they are often too complex to admit of an advan- 

 tageous study in them of the different phenomena of organized bodies. Peltier 

 conceived the ing»enious idea of employing inanition in order to rid these ani- 

 mals of ^ all superfluous matter, and to reduce them to their most simple expres- 

 sion. The following is the method which should be taken : t On a glass plate 

 let a circle of tin be glued, and in the centre of this circle place the drop of 

 water which is proposed to be examined ; on the tin circle spread a thin coat of 

 oil, with the exception of a section of a few millimetres.^ This arrangement 

 lias several advantages ; in the first place the thickness of the tin does not per- 

 mit the drop of water to extend itself by capillarit}'^ as far as the edges, and 

 entirely to flow away as ordinarily happens ; the liquid remains at rest at the 

 centre of the circle which circumscribes without touching it ; moreover, the circle 

 of oil delays evaporation. If we closed it entirely, there ensues, in 24 hours, 

 asphyxia of a great part of the animalcules ; while, by leaving a small space 

 without oil, the drop of water may be preserved from three to eight days, 

 according to the temperature and hygrometricity of the air. The animals thus 

 preserved in a drop of water will have soon exhausted all the nutritive matter 

 which it contained, and a succession of very remarkable effects produced by 

 inanition is progressively brought to view. 



In proportion as the drop of water becomes impoverished, most of the ani- 

 mals give more development and extension to their organs of contact ; fre- 

 quently new vesicles are developed on the sides of the corona of the vorticellse, 

 and avoimd tlie cephalic projections of the rostrated cyclida the protees become 

 transformed ; and the more as the drop of water has been longer kept. It 

 seems, in a word, that aliment no longer reaching the organism in sufficient 

 quantity, this organism forms a sort of hernia of all its parts in order thus 

 to reach it. At the same time that the appendages are developed, the body of 

 the animal is gradually reduced to its elements. Peltier witnessed, for instance, 

 in the vorticella al)0ve spoken of, the following phenomena : at the end of five 

 or six days of inanition, th-j agglomerations attached to the exterior mem- 

 brane of tlie animal diminish in number; when the vorticella is wholly cnfce- 



* Notice surla vie el les travaux scientifiques de J. C. A. Peltier, par sonjils. Paris, 1847. 



i Annrilcs dcs Sciences NntureUcs, February, 18:58. Vol. 9, p. H[). 



t The French measures used in this article correspond to the Eufjlisli as follows : the mil- 

 limetre =.0:5'.):>7 inch. ; milli<i^ram = .0154 graiu ; decimetre :^ 3.937 inches ; centimetre = 

 0.39371 inch. ; metre = 1.U93033 yard. 



