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in longitudinal sections. In th'ese last he saw only longitudinal 

 striations or grooves filled with ovoid nuclei, or in the form of 

 rods. In these grooves he says rectangular plates may be 

 met with like scales from the surface of hair, containing no 

 nuclei, and having the appearance of a fine line when they 

 are looked at sideways, and like a plate when seen in front. 

 The star-like forms which are seen upon the transverse sec- 

 tion would not (according to him) he produced by cells, but 

 could be marked out only by bundles of fibres cut across. 

 There would be true cells no more in the tendons than there 

 would be in connective tissue, but only nuclei or their deri- 

 vatives, the fibres of nuclei, annular fibres, and spiral fibres. 

 In a more recent work upon connective tissue (Henle's and 

 Pfeuffer's * Zeitschrift,' 1858), Henle maintains still the 

 same ideas upon the structure of this tissue. 



II. I intend to enter into rather minute details upon the 

 structure of the tendons, to show how far the analysis of an 

 apparently simple tissue requires precautions on the part of 

 the observer. It is necessary, in the first place, to choose 

 tendons so fine that the examination may be conducted with- 

 out requiring any section to be made. 



The tendons which in the tail of the small mammalia 

 terminate the spinal muscles will serve the purpose perfectly 

 well. 



The tail of a young rat, of a mouse, or, better still, of a 

 mole, being cut off" near to the base, filiform tendons may be 

 extracted of several centimetres in length by tearing off" the 

 end of the tail with the fingers. These tendons are placed 

 upon a plate of glass, and fastened at each end with sealing- 

 wax. After colouring with carmine, washing, the addition 

 of acetic acid, and slight pressure with the covering glass, a 

 preparation is obtained upon which may be observed parallel 

 stripes, red, and apparently without intermission, if the 

 examination be made with a magnifying power of 100 

 diameters. With a magnifier of 250 diameters, the red 

 stripes are observed to be cut by transverse or slightly oblique 

 lines, which divide them into segments of equal length. If 

 a rather strong pressure is then exercised upon the covering 

 glass with a needle or a scalpel, the little segments split 

 lengthwise, the two edges of the crack become separated, and 

 the cylinder is unrolled and reduced to a flat rectangular 

 cell. In the centre of this cell is found a flat nucleus, at 

 first rectangular, which soon, under the influence of acetic 

 acid, recovers itself, and takes a rounded form. The cell is 

 formed by a plate of protoplasm ; it is very evident that we 



