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DEPARTMEXr OF THE XAVAL SERVICE 



queutly, small particles of the emery as well as some from the hard tendon would 

 become inserted between the laminae and would colour the sections. In one section 

 of the disc of a rather large tendon, there were 32 dark-coloured laminae, 57 snow- 

 white ones and a large variable number of grey ones. In younger animals with 

 smaller tendons the laminae are fewer in number. It may be. as explained in the next 

 paragraph, that all three shades are in reality similar in structure, and that the 

 particles of emery and the dust_ of the teivion during the process of grinding cause 

 the apparent diiferences. 



The structure thus far referred to has been described under low powers of the 

 microscope. When higher powers are employed, as by the use of eye-piece 4 and 

 objective 6 of a Leitz microscope, the distinction between the dark and grey laminpp 

 tends to disappear. The fundamental structure then becomes like that of the finest lawn. 

 The whole tendon appears to be made iip of a network of delicate white fibres which 

 cross each other at right angles. This appearance is best seen in the thinnest portion;? 

 of a section. Where the sections are at all thick, the laminated structure is still 

 apparent, and the fine fibrils appear to combine and form bundles like those of 

 connective tissue in mammals. 







Fig. 8. Within the area A.B.C.D. ahnost all lamination has disappeared and the fine 

 delicate fibres form a networlv like the finest lawn. 



In animals recently killed, the tendons are soft and look as if they contained 

 cartilage, but when boiled and dried, as was the case in all those from which sections 

 were made for this paper, they become hard and so brittle that the thin edges easily 

 crack and break away from the rest of the disc. 



I am indebted to the Biological Board of Canada for laboratory privileges at 

 St. Andrews, New Brunswick, during the study of these sections. 



