574 PLUCKER OX THE ACTION OF THE MAGNET 



that this liquid is diamagnetic, which does not surprise us, con- 

 sidering that even the ferrocyanide of potassium proved to be 

 so : I found this equally confirmed, whether the blood of a re- 

 cently-killed frog, human blood or the beaten blood of an ox 

 was put into the watch-glass (44), and also when the corpuscles 

 were separated by filtration, dried, and suspended in the form 

 of a solid mass between the apices of the poles by means of a 

 silk-worm thread. Another point of interest was the observa- 

 tion of the corpuscles of the blood separately, as swimming in 

 the serum. 



50. To render the microscope applicable, which for this pur- 

 pose was essential, I at first used the halves of the keeper (B) ; 

 and instead of the conical points, screwed on two others, the lower 

 half of which was filed off', into them, so that, even when the 

 points ware approximated as much as possible, the glass upon 

 which the object was placed could be brought into almost abso- 

 lute contact with them, whence both the points and the object 

 could be simultaneously brought into the field of the microscope. 



In most cases, however, on account of the greater magnetic 

 tension and more ready adjustment, I preferred applying the two 

 parallelopipedal halves of the keeper (A) flat, and fixing them 

 at a distance of 3'5 millims. apart ; then placing a lamina of 

 mica or thin glass above two of the upper and opposite angles 

 of the two halves of the keeper, and so adjusting the microscope 

 that the mirror reflected the light to the object through the 

 space between the surfaces of the poles. 



51. In whatever manner the observation was made, indiffer- 

 ently whether the blood of the frog or of any other animal was 

 placed upon the glass or plate of mica, or whether it was used 

 in its pure state or mixed with water, a repulsion of the whole 

 mass of the liquid was always observed, as also a distinct repul- 

 sion of the corpuscles of the blood themselves. Hence the latter, 

 in which chemical analysis has proved the iron present to be 

 contained, appear more powerfully diamagnetic than the serum 

 in which they are originally suspended, and also more so than 

 the water in which they were placed. 



52. Milk, with its minute fatty globules, exhibited the same 

 reaction under the microscope as the blood. 



53. For the purpose of ascertaining by a direct experiment 

 whether very minute corpuscles contained in a liquid really ac- 

 quire independent movements by the action of a magnet, I placed 



