962 SUMMARY OF CURRENT RESEARCHES RELATING TO 



picro-sulpliuric mixture of Kleinenberg of one-third strength. The 

 latter, of course, destroys all calcareous structures ; but the soft parts 

 are preserved in a wonderful manner. If the diluted Kleinenberg's 

 mixture is used, let the zooids remain in it for one or two hours ; then 

 wash them thoroughly in 70 per cent, spirit, until all trace of acid is 

 removed ; then strain ; then again wash in 70 per cent, spiiit, transfer 

 them to 90 per cent, spirit for some hours, and lastly to absolute 

 alcohol ; transfer them from this to oil of cloves ; and finally, mount 

 in Canada balsam in the usual manner. If osmic acid be used, place 

 three or four of the living zooids in a watch-glass of sea-water, and 

 add a drop of the 1 per cent, solution. They should not remain even 

 in this weak solution for more than a minute, and should then be 

 thoroughly washed in a superabundance of 35 per cent, spii'it, to 

 prevent the deposit of crystals of salt consequent on the action of the 

 osmic acid ; then transfer the specimens to 70 per cent, spirit, and 

 proceed as in the other case." 



Mounting Class. — The Manchester Microscopical Society have 

 adopted the excellent idea of establishing a class for affording 

 beginners instruction in dissecting and mounting of objects, the work 

 being superintended and practically illustrated by several of the more 

 experienced members.* 



Mode of detecting Adulterations in Flour by the Microscope.t— 

 A. Cattaneo publishes two tables, with illustrative text, giving a 

 detailed account of the anatomical differences in meals and in wheat, 

 and of the adulterations of wheatmeal with the meal of rye, barley, 

 maize, rice, oat, and millet, the latter of which, however, rarely occur. 

 Besides other cereals, the flour is also adulterated with that of 

 leguminous plants, and others containing abundance of starch, as 

 the potato, horse-chestnut, Spanish chestnut, lupin, vetch, pea, lentil, 

 haricot, &c. A comparative description of the starch-grains of these 

 various substances is given. 



lleagent for small Quantities of Oxygen from Living Organisms. 1 

 — T. W. Engelmann claims to have discovered a reagent by which 

 the evolution of oxygen can be detected in any microscopic organism, 

 as, for example, a single chlorophyll-grain ; and, within certain limits, 

 even the amount of oxygen evolved be determined. The sensitiveness 

 of the reagent is so great that far less than the hundred-billionth 

 part of a milligram can be detected with certainty. It acts also so 

 quickly that sudden changes in the amount of oxygen given off are 

 indicated momentarily without loss of time. The reagent is any of 

 the ordinary bacteria of putrefaction, especially the smaller forms, 

 Bacterium termo. 



It is well known that these bacteria are, in their motile condition, 

 dependent to an extraordinary degi'ee on the presence of oxygen, 



* See Report of closing meeting for the first year, North. Microscopist, i. (1881) 

 p. 245. 



t Rend, R. 1st. Lomb. Sci. e Lett. xiv. See Bot. Centralbl. vii. (1881) 

 p. 173. 



t Bot. Ztg., xxxix. (1881) pp. 441-8. 



