Notes and Memoranda. 227 



former takes place in a dead stomach, or by contact with putrid flesh for several 

 hour3. 



Causes of Coagulation of Elood. — Professor Joseph Lister observes, in 

 the Croonian Lecture, which details elaborate experiments, "that the coagulation 

 of the blood is in no degree connected with the evolution of ammonia any more than 

 with the influence of oxygen or of rest. The real cause of the coagulation of the 

 blood when shed from the body is the influence exerted upon it by ordinary 

 matter, the contact of which for a very brief period effects a change in the blood, 

 inducing a mutual reaction between its solid and fluid constituents, in which the 

 corpuscles impart to the liquor sanguinis a disposition to coagulate.— Proceedings 

 of the Royal Society. 



Atmoltsis. — Professor Graham gives this name to operations of dialysis 

 conducted with gases, the molecules of which pass through tubes of unglazed 

 earthenware, or plates of graphite, with unequal velocities, so that a separation, 

 more or less complete, of mixed gases, can be effected by this means. He says, 

 " the most remarkable effects of separation are produced by means of the tube 

 atmolyser. This is simply a narrow tube of unglazed earthenware, such as a 

 tobacco-pipe stem, two feet in length, which is placed within a shorter tube of 

 glass, and secured in its position by corks, so as to appear like a Liebig's con- 

 denser. The glass tube is placed in communication with an air-pump, and the 

 annular space between the two tubes maintained as nearly vacuous as possible. 

 Air, or any other mixed gas, is then allowed to flow in a stream along the clay 

 tube, and collerted as it issues. ... In the gas collected, the denser consti- 

 tuent is thus concentrated in an arithmetical ratio, while the volume of the gas is 

 reduced in a geometrical ratio. In one experiment the proportion of oxygen 

 in the air, after traversing the atmolyser, was increased to 24*5 per cent., or 167 

 upon 100 oxygen originally present." — Proceedings of the Royal Society, No. 56. 



Boss's New Compeessoeittm:. — Microscopists who have suffered the incon- 

 venience inseparable from ordinary forms given to a compressorium, will thank us 

 for calling their attention to an entirely new pattern devised by Mr. Ross. It con- 

 sists of a stout plate of brass about three inches long, having in its centre a pieceof 

 glass like the bottom of a live box. This piece of glass is set in a frame which 

 slides in and out, so that it can be removed for the convenience of preparing any 

 object upon it, under water if desirable. The upper moveable part, attached to a 

 screw motion, is admirable for simplicity and efficiency. At one end of the 

 brass plate, which forms the bed of the instrument, is an upright piece of brass, 

 accurately grooved so as to receive a vertical plate, to which a downward motion 

 is given by a single fine screw,, surrounded by a spiral spring, which elevates the 

 plate as soon as the screw pressure is removed, by turning the milled head the 

 reverse way. The vertical plate carries an arm precisely at right angles to its 

 own plane, and terminating in a square frame capable of receiving very thin or 

 somewhat thicker glass according to desire. This is the upper part of the com- 

 pressorium, and the exact amount of pressure required is completely under com- 

 mand by the motion of a single screw. The arm has likewise a horizontal motion, 

 so that the upper glass, plate can be turned completely off the lower one. Should 

 the thin upper glass be broken, it can be instantly replaced, as no cement is required. 

 It is merely needful to remove the fragments, and slip a fresh glass in. We do 

 not know any compressorium that is at once so accur ite and so easily used. If 

 required, a duplicate frame, carrying a thin bottom glass, can be obtained, and it 

 would be very easy to contrive a support, as in the pattern of M. Quatrefages, by 

 which either side of the object could be viewed. It, often happens that on account 

 of the trouble of an ordinary compressorium, a microscopist simply uses a slide 

 and a piece of covering glass, and finds when too late that an exact means of regu- 

 lating the pressure would have been desirable. With Mr. Ross's new pattern the 

 convenience is so great that it should always be employed if there is a chance of 

 the screw motion being advantageous. 



Eaethquakes at Ejiodes. — M. Jouanin, gerant of the French Vico-Con- 

 eulate, gives an account in Cosmos of the disturbances in that island since I860 ; 

 and he likewise mentions a severe shock which occurred on 12th October, 1856, 

 accompanied by vertical oscillations. In the year 186*0 earthquakes occurred 



