Dr. Beale, on Sarcolemma, 
105 
Besides this elaborate network of nerve-fibres extending 
over the sarcolemma, there is an arrangement of the tracheae 
equally elaborate, forming, in fact, a network of extremely 
minute tubes, which, like the network of nerve-fibres, extends 
over every part of the sarcolemma. The mode in which the 
tracheae reach the sarcolemma and divide upon its surface, 
is well seen in some parts of fig. 1, and in fig. 7 many 
of the fine branches of the tracheae are visible. It will be 
seen in this specimen that anastomoses are very frequent, but 
the finest branches of the air-tubes are not to be seen by the 
aid of a magnifying power of two or three hundred diameters. 
By the use of a much higher power and properly prepared 
specimens branches far more minute than any represented in 
fig. 7 are brought into view. These are represented in 
figs. 3, 4, 5, 6, and 9. They anastomose freely with one 
another, forming a network of air-tubes, which is inti- 
mately adherent to the sarcolemma. The finest branches 
of the nerve- fibres and the finest branches of the tracheae 
are situated very close to one another. Bundles of fine 
nerve-fibres may often be seen ramifying with tracheae of 
considerable diameter, as they pass to be distributed on the 
sarcolemma. The relation of the finest nerve-fibres to the 
finest tracheae is shown in figs. 3 and 9. 
It may, perhaps, strike some as very strange that an ar- 
rangement so elaborate as that which is represented in my 
drawings has not been demonstrated by any previous observer ; 
but when it is considered how many delicate operations 
must be successfully carried out before it can be demon- 
strated — and even in properly prepared specimens, in which 
it is to be seen, how difficult it is to remove the most favor- 
able portions, immerse them in fresh fluid, and cover them 
with thin glass, without destroying the appearance alto- 
gether — it is not surprising that it should have been over- 
looked. Neither the finest tracheae nor the finest branches 
of the nerves described in this paper have been observed 
before. That the arrangement of the finest tracheae deli- 
neated in my drawings is exactly as it exists in nature can 
be demonstrated by any one who will examine the speci- 
mens. But not a vestige of such minute branches is to be 
seen in specimens prepared according to the usual methods. 
The fine nerve-fibres I have described, as would be sup- 
posed, are very readily disintegrated, so that it is only in 
fortunate specimens that the appearances delineated can be 
seen ; but, having seen these fine fibres in very many instances, 
I have no doubt that the description I have given of the 
distribution of the nerves and finest air-tubes to the muscles 
