FORMATION OF LACUN^:. 151 



stellate, and at last the calcification of the intercellular 

 substance ensues ! " According to this view the cana- 

 liculi are the processes of the cell which "bore" 

 their way through the already calcified tissue, and in 

 some unexplained mysterious manner manage exactly 

 to meet the processes of adjacent cells, and become 

 continuous with them. Canaliculi, however, exist 

 long: before the formation of the calcified tissue is 

 complete. 



There are few points in minute anatomy upon 

 which such different views have been advanced as 

 the one under consideration, for observers differ not 

 only in the explanations and opinions they have put 

 forward, but there are irreconcilable difierences re- 

 garding their statements of fact. To assert that the 

 cells throw out processes is merely fanciful, for there 

 are no facts whatever to justify such a statement. 

 Although it has been repeatedly stated that the bone 

 " cell " with its canaHcular prolongations may be 

 actually detached from the matrix into which its 

 processes have bored their way, I have never been 

 able to obtain any specimens which appear to me to 

 justify such an inference, while I have utterly failed 

 in every attempt to prepare specimens which would 

 lead me to infer the existence of any grounds for such 

 a conclusion. 



With regard to Virchow's view, it may be remarked 

 that althougfh it is true that in certain cases in which 

 the bioplasm is more or less stellate, the so-called 

 processes project a very short distance from the mass, 

 they never, as far as can be ascertained, correspond in 

 number with the canaHculi which exist in the fully 

 formed bone, the latter being twice as numerous as 

 the processes in question. Almost any form of bio- 

 plasm may exhibit this stellate appearance, but it has 

 nothingf whatever to do with the formation of the 

 canaliculi in bone. That part of the canaliculus nearest 

 to the lacuna is the last that is formed, whereas if the 



