3G SCHMIDT ON THE COMl'AUATIVE PHYSIOLOGY 



such importance in general physiology, of the evolution of oxygen 

 as t lie final result of an inverted vital-reaction (StoiTwechsel) or 

 respiratory process of these organisms. He had the kindness to 

 draw my attention to the phaenomenon itself, as also to the ex- 

 cellent material for minute examination, and pointed out to me 

 the locality and the very spot (in the Rodenberg saline spring) ; 

 the undertaking and happy issue of this investigation are owing 

 indeed to his friendly advice and assistance. I arrived at the 

 saline spring at three o'clock one afternoon in the end of Sep- 

 tember. A whitish mucous mass covered the bottom of the brine 

 reservoirs, between the layers of which bubbles of gas 1" to |' long 

 and 2'" to 2" broad were inclosed. Stirring with a stick caused 

 an enormous evolution of gas. A glowing chip of wood was set 

 in a flame three times in succession when inserted into an ale- 

 glass which had been filled a few seconds previously. Observation 

 made with a good Oberhauser's microscope upon the spot, showed 

 that no trace of Confervce or other forms than the Frustulia, 

 could be detected in the fresh mucous masses which were up- 

 permost, especially in those which were filled with this air loaded 

 with oxygen. 



The central, round, eye-like masses, which Ehrenberg pointed 

 out to be male seminal glands, as also the narrow ones lying on 

 the lateral walls of the siliceous carapace towards its apex, and 

 Avhich this philosopher considers as ovaries, wereyellowish-brown. 

 Microscopic reactions, as also the combustion-tube, appear to 

 confirm the correctness of this view ; these masses, as men- 

 tioned at p. 11, consist of fat. It was noticed at the same time, 

 that potash appeared to dissolve the other contents of the sili- 

 ceous carapace. The residue, after treatment with aether and : 

 dilute solution of potash, was considerable. It was proved (0*415 

 being heated to redness with soda-lime) iohe free from nitrogen', 

 the results of elementary analysis were 



0-6275 of the substance dried at 248° gave 0*527 carbonic acid ! 

 and 0-186 water. [ 



0-6275 left 0-316 ash (silica) in the small platinum vessel.' 

 Hence in 100 parts of the substance free from ash there was — 

 Carbon . 46-19 

 Hydrogen 6-63. 

 This result agrees perfectly with that obtained by Rochleder and 

 Heldt as a mean of seven determinations for the cellular mem- 

 brane of lichens : they found — 



