ON THE STRUCTURE OF HYALINE CARTILAGE. 13 



to be arranged in groups, the divisions between the groups 

 being -wider than those between the individual bands. It 

 has not been considered necessary to give a drawing of these 

 groups, which morj)hologically find their analogues in other 

 forms of connective tissue. 



In scaled preparations of cartilage there are sometimes 

 to be seen lying free on the surface of the section, or more 

 frequently free in the fluid near its edge, isolated flattened 

 cylindrical bands, of a like breadth to those described as 

 being arranged in parallel layers in the cartilage-substance, 

 but differing from them Avhen in situ in the following par- 

 ticulars : — They are puckered transversely, the puckerings 

 being formed by parallel transverse ridge-like discs separated 

 from each other by a hyaline substance. Frequently the 

 end of such an isolated band bulges over the end of the 

 cylinder as a flocculent coherent mass. I'ig. 19 is a copy 

 of a drawing made by Dr. Ewart from a preparation of the 

 head of a frog's. femur an hour after it had been sealed in 

 blood-serum, which was obtained by beheading the animal. 

 Such isolated bands can be seen in preparations of other 

 forms of connective tissue similarly treated, and more 

 abundantly if the tissue has been inflamed. When seen 

 isolated it is impossible to distinguish the form of tissue from 

 which they have been separated. The appearance of such an 

 isolated cylindrical body, whether from hyaline cartilage, 

 neurilemma, or an inflamed cornea, is identical. As in some 

 tissues this cylindrical band is farther resolvable into a num- 

 ber of exceedingly fine fibrillee, the author in his previous 

 histological papers, taking the fibrilla as the ultimate unit, 

 has applied the term jn^imary bundle to such a cylinder or 

 rod. 



Now follows the history of a remarkable preparation. 

 In December, 1874, a number of aqueous-humour prepara- 

 tions of transverse sections of the cartilage of the metacarpus 

 of the sheep were sealed. One of these, about which 

 nothing was noted, although it was presumably frequently 

 examined during the first fortnight, was laid aside in order 

 to observe any further changes that might folloAv. It was 

 not looked at again until July of this year, and Avhen then 

 examined it presented the following microscopic characters : 

 • — The substance of the cartilage, to jndge from its uneven 

 appearance, had apparently undergone some disintegration ; 

 the granular protoplasmic cells had become very small, and 

 lying free in the surrounding fluid were swarms of large, 

 irregularly and variously shaped, finely granular bodies, beset 

 with vacuoles which corresponded in shape and size with 



