ANATOMY 



wonderful series of events occurring during the 

 growth of any animal provided with a bony 

 skeleton. As the happenings are exceedingly 

 intricate and complex, it will only be possible to 

 notice some of the most interesting. 



The human thigh-bone first makes its appear- 

 ance in miniature, and modelled not in bony sub- 

 stance, but in cartilage. Cartilage is a tissue which, 

 in consistence like hard india-rubber, is very 

 elastic and flexible, and well serves the purpose of 

 a skeleton substance in the early stages of life. 

 Owing to its flexible skeleton, containing as it 

 does a large proportion of cartilage, an infant 

 often escapes severe injury in an accident which 

 plays havoc with the more rigid skeleton of an 

 adult. 



When cartilage is sliced and examined under 

 the microscope it is found to be an exceedingly 

 simple tissue innumerable small bodies, or cells, 

 occupying minute cavities in a homogeneous sub- 

 stance having a striking resemblance to ground 

 glass in appearance. It may be aptly compared to 

 almond toffee, supposing the toffee were replaced 

 by a resistant semi-translucent jelly ; the almonds 

 being the counterparts of the cells, the toffee the 

 substance in which the cells are embedded. One 

 of the remarkable features of cartilage is that it 

 is a bloodless tissue, containing no blood-vessels. 

 Being devoid of blood-vessels, the method by 



219 



