1870.] Zoology. 437 



of the stroke in the movement of the wing. The movement of the 

 wing itself is recorded by an arrangement with an electric current, 

 wires being connected with a small instrument carried on the bird's 

 back. The impulse upwards or forwards is also recorded by means 

 of an elastic bag containing air, on the surface of which lies a piece 

 of lead : when a sudden movement occurs at right angles to the 

 plane of the lead plate, it compresses the air in the bag by its inertia, 

 and this movement is recorded by means of a tube, another bag and 

 a lever, as in the cardiograph. 



Peregrinations of Cells in the Living Body. — The study of living 

 tissues to which Cohnheim's views on inflammation (viz. that there is 

 no multiplication of the cells of connective tissue, but that pus cells 

 are extra vasated white blood corpuscles) have given rise, progresses 

 very rapidly in Germany under the hands of Yon Kecklinghausen 

 of Wurzburg, of Strieker of Yienna, of Eollet of Gratz, and their 

 pupils. It appears certain now that both white and red blood cor- 

 puscles do freely pass through the capillary walls in inflammation ; 

 but it is equally certain, from the admirable researches of Strieker, 

 that cells multiply in inflammation which are not white blood cells, 

 such as the stellate cells of the cornea, the corneal epithelium, the 

 connective-tissue cells of the tongue, and others which Strieker has 

 seen under his eyes commence and finish the act of division. Among 

 the most remarkable results recently obtained from this study of 

 living cells is the observation of Saviotti, that cells pass into the 

 capillaries and small veins as well as out of them. He has seen 

 this frequently occur with the pigment cells of the frog's web, 

 when inflammation was set up by dilute sulphuric acid, and the fact 

 was recently witnessed also in the laboratory of Professor Strieker, 

 of Yienna. The pigment-cells deliberately advance to the capillary 

 wall, and passing through it are carried along in the circulation. 

 These facts as to living cells are so remarkable that some have been 

 inclined to suppose there is optical illusion. They are, however, 

 now placed beyond doubt by repeated observation. Movements of 

 cells in the tissues may now be demonstrated in many parts as well 

 as the cornea, in the frog's egg of the second day, in the brain, in 

 the foetal liver, in the skin (migrated cells of Besiadecki) • and hence 

 Kolliker's supposition that all cells at one time or other can exhibit 

 active movement is likely to be established. Eecklinghausen has 

 kept an excised frog's cornea alive for six weeks by supplying it 

 with fresh serum and attending to cleanliness ; a wonderful proof 

 of independent vitality. 



Physiology in Trinity College, Cambridge. — Trinity has lately 

 proved her claim to stand alone and at the head of the colleges in 

 Cambridge by the establishment of a praelectorship in pure physiology, 

 to which that able teacher, Dr. Michael Foster, of University Col- 

 lege, London, and Fullerian Professor in the Koyal Institution, has 



