70 M. F. Plateau on the Aquatic Articulata. 



has worked, perhaps for centuries, perhaps for millions of 

 ages, to bring about some beneticent result, if we can but catch 

 a glimpse of the wheels, its divine character disappears." 



I agree with the writer that this first conclusion is prema- 

 ture and unworthy ; I will add, deplorable. Through what 

 faults or infirmities of dogmatism on the one hand and scepti- 

 cism on the other it came to be so thought, we need not here 

 consider. Let us hope, and I confidently expect, that it is not 

 to last — that the religious faith which survived without a 

 shock the notion of the fixity of the earth itself, may equally 

 outlast the notion of the absolute fixity of the species which 

 inhabit it — that, in the future even more than in the past, 

 faith in an order, which is the basis of science, will not (as it 

 cannot reasonably) be dissevered from faith in an Ordainer^ 

 which is the basis of relio-ion. 



YIII. — Physico-chemical Investigations upon the Aquatic 

 Articulata. By M. Felix Plateau. Part II.* 

 The first part of my investigations, of which an abstract was 

 published in this Journal in 1871 (vol. vii. p. 362), contained 

 the results of my experiments on the causes of the death of 

 the freshwater Articulata in sea-w^ater, and of the marine Ar- 

 ticulata in fresh water. 



In the present memoir I take up three other interesting 

 questions connected with the life of the aquatic Articulata — 

 questions of detail indeed, the solution of which could not 

 open any new vista in comparative physiology, but which, 

 carefully treated, have led me by numerous experiments to 

 curious and sometimes unexpected results. 



I. Experiments on the time during which the aquatic Articidata 

 can remain in the water without coming to the surface to hreathe. 



The swimming aquatic Articulata with aerial respiration 

 (Coleoptera in the perfect state and Hemiptera) come frequently 

 to the surface to renew their provision of air. If we pre- 

 vent them from performing this operation, what will be the 

 time during which they may with impunity be subjected to 

 submersion ? Is their resistance to asphyxia greater than that 

 of terrestrial insects? or only equal or inferior to it? 



The experiments were efiected as follows : at the bottom of 

 an open vase of the capacity of one litre, and full of ordinary 

 spring water aerated, a smaller vessel containing about 200 

 cubic centimetres is placed ; a piece of cotton net is stretched 



* Bulletin de I'Acad. Roy. de Belgique, 2« s^r. tome xxxiv. nos. 9 & 10, 

 1872. From an Abstract by the Author. 



