NERVE ENDINGS, STOMACH AND SMALL INTESTINE 557 
In the net-like terminal structures the component fibrils appar- 
ently anastomose to form a reticulum (fig. 2). The central re- 
gion of this reticulum sometimes takes on a slight stain suggesting 
the presence of some homogeneous substance on or in which the 
net lies. 
Not infrequently the strand of fibrils into which a main fiber 
divides continues for some distance without developing skeins or 
nets and interlaces with other fibrils to form a wide-meshed plexus 
running through the muscular tissue. From this plexus terminal 
skeins, and in some cases terminal networks, may be given off 
laterally. Loops from such an interlacement of fibrils have been 
traced into the serous coat, where they give rise to terminal 
nets. 
ENDINGS IN THE LONGITUDINAL MUSCLE OF THE SMALL 
INTESTINE OF THE DOG 
In the longitudinal muscle of the dog’s small intestine meth- 
ylene blue staining has revealed nerve terminals to which the 
name of end tufts may appropriately be given. Each occurs 
at the extremity of a fine, non-medullated, varicose fiber, which 
has been seen, in the limits of a single section, actually to emerge 
from the myenteric plexus (fig. 3). Such fibers are noticeably 
finer than certain others (such as the one marked ‘mf.’ in fig. 
3) which run parallel to the muscle cells, and have been traced 
to sumple motor endings on these cells. 
The structure of the end tufts themselves is difficult to make 
out satisfactorily even with the highest powers of the microscope. 
Under oil immersion they appear to consist of exceedingly deli- 
cate fibrils liberally besprinkled with minute varicosities (fig. 4). 
The exact relation of the ultimate fibrils to one another has not 
been positively determined, but the impression gained has been 
that they spread out into a brush- or tuft-like structure without 
uniting into a network. Except for the extreme delicacy of its 
fibrillar constituents the ending under consideration bears a 
general resemblance to the intermuscular end arborizations 
(‘Endbiiumschen’) described by Ploschko (’97) as terminating a 
rather large medullated nerve fiber in the wall of the trachea. 
