24G 



MANUAL OF HISTOLOGY. 



possessing no regular internal layers, is one which has been frequently 

 discussed^ but not yet conclusively answered. 



A method of isolating from the ground-mass by means of alkalies or 

 concentrated mineral acids, a something corresponding to these lacunae 

 and canaliculi, has been known for many years past. The structures so 

 laid bare have been looked upon by some as being a soft cellular net- 

 work, by others as made up of the lining layers just mentioned of the 

 system of canals. 



And not alone from fresh bone do we succeed in isolating the reticular 



mass in question, but also from that in which all the softer tissue must 



have been destroyed by maceration ; even in bony masses which have 



been made use of for turning, it may be 



/ separated, as Neumann has shown ; so that 



w^ * ^A^J^ ^ or our own P ar ^ we mus ^ Declare ourselves 



K*V on the side of those who maintain the exist- 



jf[ yfmjr-l> ence f an independent calcified wall. 



\ We have now taken a survey of the canali- 



sation of bony tissue, but have not yet become 

 acquainted with the cellular elements imbedded 

 in the lacunae. These " bone-cells," as they are 

 called, were for a long time overlooked, owing 

 to the practice so much in vogue amongst 

 former anatomists of examining principally 

 macerated osseous structures. But after some 

 earlier observers had given it as their opinion 

 that nuclei were to be seen here and there in 

 the lacunae, general attention was directed to 

 the cells of osseous tissue by Vircliow. 

 And, indeed, it is a matter of slight difficulty to obtain bodies re- 

 sembling cells from structures belonging to this class. For this purpose 

 we make use of fresh bone (fig. 239), which has been either simply 

 macerated in hydrochloric acid or subsequently boiled ; 

 or, better still, which has been boiled for a short time 

 in a solution of soda after having been previously treated 

 with the acid just mentioned. In the now soft and 

 almost liquid intercellular substance (6) we see struc- 

 tures similar in form to the figures of the pre-existing 

 lacunae, with shorter or longer processes, definite walls, 

 and each with an oval or elongated and more or less 

 sharply defined nucleus, and measuring on an average 

 0*0074 mm. The most striking objects are to be 

 obtained by cautiously squeezing and moving the 

 glasses between which the tissue is placed, when some of the cells may 

 be freed from the intercellular matter clinging to them (a-d). 



These " isolation products " were regarded by some as stellate cells with 

 remarkably resistent envelopes, in that the persistence of cell-body 

 invested with an ordinary membrane, or even completely naked, was out 

 of the question after boiling in caustic soda. 



But careful observation of fresh bone will lead to other conclusions. 

 Under cautious treatment, aided by carmine tinction, we may recognise in 

 the lacunae (fig. 240, a) small, membraneless, indistinctly oval cells (b), 

 with small projections, at times very short, which are directed towards 

 the openings of the canaliculi. They are possessed also of elongated 



Fig. 239. Figures resembling cells 

 from the diaphysis of the femur, 

 with nuclei at a and c ; 6, with a 

 portion of the softened inter- 

 cellular substance: d, another 

 whose nucleus has broken up 

 into granules. 



Fig. 240. Bone -cell 

 from the fresh 

 ethmoid bone of the 

 mouse ; tinged with 

 carmine. 



