INDUSTRIAL PROGRESS DURING THE YEAR 1875. cxlix 



livers and kidneys of dogs, killed for this purpose by femoral 

 bleeding. To eliminate sources of error, and especially en- 

 trance of air by the wound, he placed a ligature at the level 

 of the hilum of the liver and kidney to be experimented on, 

 the organs were removed, preserving their envelope of con- 

 nective tissue, and the ligature was used to suspend the or- 

 gans in the bath. Examination some days after showed that 

 the surface was hardened throughout, but the central parts 

 were full of bacteria ; the chromic acid at once arrested their 

 movement. Hence he concludes : 1. That MM. Bechamp 

 and Estor's demonstration of the production and evolution 

 of bacteria in organic tissues protected from air-germs is 

 quite exact. 2. That the effect produced by preservative 

 agents is the death of microzymes, or molecular elements 

 surviving in the organs. 



III. THE CHALLENGER AND TUSCAEORA SOUNDINGS. 



Dr. Wyville Thompson says, in his report in the Proceed- 

 ings of the Royal Society, No. 156, that in latitude 60 52' 

 south, longitude 80 20' east, also 53 55' south, and 108 35' 

 east, the sounding instrument came up filled with a very fine 

 cream-colored paste, which scarcely effervesced with acid, 

 and dried into a very light impalpable white powder; exam- 

 ined under the microscope, it was found to consist almost en- 

 tirely of the frustules of diatoms, many broken, and some 

 wonderfully perfect ; with these were rods of a singular 

 silicious organism, hollow, and, as subsequently obtained 

 floating by means of a tow net, a little to the north of the 

 Heard Islands, containing the characteristic endochrome of 

 the diatoms. The tow net was at this time filled with a 

 pale yellow gelatinous mass of diatom ooze, and Professor 

 Thompson, considering the bottom Diatomacese as dropped 

 from this belt of diatom ooze, as he terms it, and which was 

 found somewhat farther southward, attributes the difference 

 of position to the reflux of the Agulhas current. The exist- 

 ence of diatom ooze over vast surfaces of the Pacific is abun- 

 dantly proved from the soundings of the Tuscarora. Many 

 of these consist of diatoms only, and as they are not in the 

 semi-fossil condition of those obtained by the Challenger, but 

 still with endochrome within the frustules, and the ooze itself 

 of a yellowish-green tint, it is but fair to conclude that ex- 



