219 



buds cilher directly or by branches. The oiilf^rowlh of 

 muscle reseuiblcs very much thai of nerves in lissue culture. 

 There is one capital difference, namely that the nerve out- 

 growth is entirely without nuclei, while the muscle fibre 

 contains many nuclei both in the protoplasmic buds and 

 in the connecting fibres. 



P r e m u s c 1 e was studied by C o n g d o n i*'^), H e a r t 

 muscle has been studied by Burrows -^) ^9), Congdon 



1«), Levi 328) 333) and O 1 i V O 427) 428). 



Smooth muscle, rather the ordinar}' mesenchyme, has 

 been studied by Lewis and Lewis ^ss) ]\,j i\ Lewis 

 3*3). The contraction of the smooth muscle cell was studied 

 by M. R. Lewis 357). 



The connective tissue cells from adults have 

 been beautifully described by M a x i m o w ^^o). 



The endothelium was investigated by Carrel and 

 Burrows 74) and W. H. Lewis 3go f). 



The cartilage was studied first by Carrel and 

 Burro w s "*) and later in pure permanent strains by 

 Fischer i^*). 



