of Edinburgh, Session 1879-80. 
707 
rises by growth of the cartilaginous zone immediately above the 
primary cancellous spaces. 
2nd, The extension of the shaft occurs by opposition to its 
extremity, thus keeping up with the recession of the epiphysis. 
The extension of the shaft in length does not lift the head. 
The area of proliferation in which these changes occur at the end 
of the shaft lies in an angular groove at the point where the neck 
joins the epiphysis, called by Ranvier encoche d’ ossification. 
This author describes fibres in the outer part of the encoche, that 
is the periosteum, which stretched from the periosteum to the 
cartilaginous head in which they became lost. 
The existence of these is undoubted, and very general. 
Origin of the Osteoblasts . — These organisms, which have the 
function of resorping bone, occur in certain well-marked situations ; 
their origin is from the perivascular connective tissue, i.e., within a 
short distance of the line of ossification under the epiphysis, and 
extending over a considerable area, they diminish the number of 
spicules opening up the cancelli. Under the head of bones, the 
epiphysis of which have a greater sectional erea than the shaft, and 
in those positions where the head projects beyond the shaft exter- 
nally along the interior of the shaft wall. 
3. On the Wire Telephone and its Application to the Study 
of the Properties of strongly Magnetic Metals. By Pro- 
fessor Chrystal. 
Pour distinct sources of sound were noticed in the course of the 
experiments. 
1. The variation of the longitudinal tension of the wire, owing to 
variation in the heating, still appears to be the most likely explana- 
tion of the action of the wire telephone, when a very fine wire of 
ordinary metal is used. Experiments were tried with induction 
coils of various sizes, the violin and microphone being put into the 
primary circuit and the fine wire telephone into the secondary. It 
was found that the sound diminished as the spark-giving power of 
the coil increased. With Professor Tait’s large induction coil no 
sound at all could be obtained, when the secondary was closed 
through the most sensitive wire I possess. 
