14 
nection with, these fine muscular fibres present several points 
which will well repay attentive study. These masses of 
germinal matter are sometimes twice or three times the width 
of the fibre with which they are connected. In a paper pub- 
lished in Part XIV of my ‘Archives 5 I have adduced facts 
whirli render it probable that these nuclei or masses of 
germinal matter change their position in a very remarkable 
manner during life. 
The conclusions I have arrived at upon this point are as 
follows : 
The masses of germinal matter appear to move along the 
surface of the already formed muscular tissue, and as they 
move part of their substance becomes converted into muscle 
(PI. Ill, fig. 13). It is in this way that new muscle is formed 
and new muscular tissue is added to that already produced. 
The germinal matter itself does not diminish in size, because 
it absorbs as much pabulum as will compensate for what it 
loses of its own substance by conversion into tissue. In the 
young muscle the nucleus increases in size. 
From what I have observed, I think that these oval masses 
of germinal matter move in different directions, but always in 
a line with the fibrillated structure, so that in a muscle some 
will be moving upwards, some downwards ; and when the 
nuclei are arranged in rows or straight lines, the nuclei lying 
in adjacent lines will be moving in opposite directions. 
During the formation of a muscle these masses undergo divi- 
sion in two directions, longitudinally and transversely. The 
two masses which result from the division of one will pass in 
opposite directions. 
As is well known, the position of these nuclei with respect 
to the formed muscular tissue is very different in different 
cases. Sometimes they are in the very centre of the elemen- 
tary fibre, as in the constantly growing fibres of the heart, 
sometimes upon its surface only, sometimes distributed at 
very equal distances throughout its substance. Wherever 
these nuclei are situated, new muscular tissue may be pro- 
duced, and it is only in these situations that muscular tissue 
ever is produced ; so that by the position of the nuclei we 
learn the seat of formation of new muscle at different periods 
of life. 
The facts which I regard as favorable to the view above 
expressed concerning the movements of the masses of germinal 
matter of muscle, are derived from many sources, but I will 
refer to some observed in the case of the muscles of the 
papillae of the tongue. Here the muscular fibre is very thin 
and delicate, and very favorable for observation. The mass 
