THE OSSEOUS SYSTEM. 319 



nizable only from their peculiar stellate cavities, — the so-termed hone- 

 corpuscles, or lacunce and canaliculi. 



"With the kno\Yledgc thus obtained of the formation of the lacunse in 

 rachitic bone, the endeavor to arrive at an insight into the same process 

 in normal bone, is no longer attended with as much difficulty as before, 

 when the inquirer was involved in a maze of hypotheses of the most 

 various kinds, and all without any certain foundation. The investigation 

 of the conditions attending the development of bone, both in man and 

 other animals, must nevertheless still be regarded as troublesome, and 

 frequently little worth the pains bestowed upon it. It is, perhaps, cer- 

 tainly manifest {yid. " Mik. Anat.," tab. iii. fig. 6), that the bone-cells, 

 a little beyond the limit of ossification, become thickened, and, still 

 presenting the remains of their cavity and the nucleus, beset with cal- 

 careous particles ; and although such incrusted cells may even be isolated, 

 yet the mode in which the changes are eftected further on, is not, beyond 

 a short distance, I must affirm, to be seen with anything like the dis- 

 tinctness that it is in rachitic bone, because, more internally, the newly- 

 formed medulla with its vessels, and the calcareous particles, render 

 almost everything indistinct; and it is not till we get to the homogeneous 

 and more transparent osseous tissue beyond, that distinct, but almost 

 perfectly-formed lacunas come into view. Nevertheless, from all that 

 we see, there cannot be the least doubt, but that the processes are 

 essentially the same as in rachitis, only, that in the healthy bone the 

 ossification of the thickened walls of the cartilage cells, presents two 

 stages, instead of only one, as in the former case, inasmuch as they first 

 appear granular from the deposition of the calcareous particles, and 

 afterwards homogeneous. Moreover, even in perfectly normal bone, in 

 the adult, I have met with places (some of which, independently of me, 

 have also been lately described by H. Meyer (1. c.) ), such as the sym- 

 physis pubis, the synchondroses of the vertebrae, and those of the ilium, 

 sacrum, and the points of insertion into the bones of certain tendons 

 containing cartilage-cells. In all of these situations, at the line of 

 junction between the cartilage or tendon and the bone, cartilage-cells of 

 the most characteristic aspect may be seen, lying free in the cartilaginous 

 matrix, and presenting the most various degrees of transformation into 

 bone-cells ; some, in particular, having thickened walls, and a more or 

 less copious deposit of calcareous particles ; while others are almost 

 perfectly-formed bone-cells, with pores and a more homogeneous wall 

 (Fig. 123); so that I am able to afi'ord a certain support to the state- 

 ment given above with respect to the mode of origin of the bone-cells, 

 by the conditions presented in normal tissues also. In the last-named 

 situations I have, likewise, very distinctly and very frequently noticed, 

 half- or wholly-ossified parent-cells, containing from two to twelve 

 secondary cells. 



