250 
On the Structure and Development of 
puscles and an intermediate fibrillar substance. The exact relation 
of the fibres to the cells has never been thoroughly stated of all 
these tissues, but it seems proper to conclude from the fore- 
going statements that in each instance the plate-like cells are 
superimposed on the fibres and form in this way, often, a partially 
investing sheath. The envelope which is the investing substance 
of the plate-hke cells forms a bed upon the bundles to which they 
adhere very strongly. By their processes these envelopes anas- 
tomose with other adjacent bodies of like structures ; they do not 
always anastomose, however, or do not appear to, and may be quite 
free. In the cornea they often unite and often do not, but, in so 
doing, they extend their processes through the channels which are 
supposed to convey lymph from the corneal spaces. Klein's view 
that netted cells form the network in adenoid tissue is untrue in 
many cases, judging from the observations that were made, for it 
was found possible to brush ofi' many of the bodies, showing that 
they were on the tissue and not in it. These so-called cells were 
also seen by sufficiently high powers to be fibrillated, and therefore 
not " netted cells," but bundles of larger or smaller size. 
Elastic Tissue. — 1. There are no corpuscles that have been 
found in adult elastic tissue that can be positively shown to belong 
to it exclusively. In young tissue they certainly occur, according 
to excellent authorities, but they do not maintain their integrity 
long. Possibly higher powers than those in use may discover the 
bodies mentioned by Eecklinghausen and Thin, but at present they 
elude our observation. 
2. The fibres are cylindrical and branch dichotomously, and 
they exhibit an indifference to micro -chemical reagents that is not 
shared by others of the connective-substance group. They do not 
appear to be made up of fibrillae, but each elastic cord is the 
ultimate element. They have no necessary connection with the 
other connective substances, and that they are not always present 
may be shown by boiling adenoid tissue and tendon tissue in the 
solutions of caustic potash before mentioned, when it will be found 
that these substances will dissolve entirely, which would not be the 
case if elastic fibres were present, for they resist the action of 
boiling acids and alkalies, as we have seen. We have stated that 
in the intermuscular tissue of the frog's thigh, which is extremely 
rich in elastic networks, there are numerous large and flattened 
corpuscles, which rest, apparently, upon broad and flattened plates 
of a fibrillated character, and here it often appeared as if the flat- 
tened bodies were continuous with the firm branches of the net- 
work. In other cases the elastic fibres pass directly over the 
plate-like body. Whether, however, there is a connection between 
them as Adickes * claims, is difficult to determine. 
* ' Arcliiv. tier Heilkuude,' iv., 1872. 
