98 
Dr. BealE; on Sarcolemma. 
of nuclei, and when the very fine nerve-fibres passing between 
these are destroyed^ or^ owing to the refractive power of the 
fluid in which the specimen is examined, are rendered com- 
pletely invisible, which is invariably the case in specimens 
immersed in fluids consisting principally of water — a defective 
method still pursued by Kiihne and others in Germany — the 
appearance is that of a little collection of nuclei upon or be- 
neath the surface of the sarcolemma. And as it often hap- 
pens that small dark-bordered fibres (the subdivisions of which 
are really distributed to muscular fibres at a long distance 
from the point of the specimen under observation) here lose 
their dark-bordered character, and in preparations mounted 
in aqueous fluids cannot be followed much beyond this point, 
the dark-bordered fibre often appears as if it ceased, and was 
connected with the collection of nuclei. 
When such collections of nuclei are protected from the 
immediate pressure of the thin glass by a layer of thin ele- 
mentary muscular fibres, they appear, in specimens immersed 
in aqueous fluids, to be beneath the surface of the sarco- 
lemma. This is one of the explanations of the appearances 
observed by Kiihne, Rouget, Engelmann, and others. Such 
collections of nuclei, supposed to be beneath the sarcolemma, 
have recently been described by Kiihne as nervenhilgel ; and, 
although twenty-four years ago such nuclei could not, by 
any possibility, have been seen by the microscopes then in 
use, or demonstrated by the modes of preparation then 
employed, these collections have been christened after 
Doyere, who traced bundles of nerve-fibres to the surface of 
the muscles of certain tardigrada;"^ and, as his means of 
investigation prevented him from being able to trace their 
further ramification, he naturally inferred that they termi- 
nated there. The eminences figured by Doyere are the 
points at which a bundle of nerve-fibres reaches the muscle, 
and the fibres commence their ultimate ramifications upon 
the surface. Kiihne's recently discovered Doyereschenhiigel 
* Doyere, as would be supposed (writing twenty-four years ago), says 
nothing about the relation of the nerve-fibres to the sarcolemma^ but describes 
them as spreading out over the surface of the muscle, sometimes extending 
over its entire length. The muscle represented by him in pi. xvii, fig. 4, 
seems to be perfectly continuous in structure with the nerve-fibre. It 
is quite impossible to say which is nerve and which muscle. Kiihne 
seems to support this idea of Doyere, that the contractile tissue of the 
muscle passes by continuity of structure into the nerve. After writing 
voluminous memoirs and arriving at novel conclusions, the Berlin anatomist 
at last discovers the truth by going back twenty-four years ! See " Memoire 
sur les Tardigrades * Ann. des Sciences naturelles,' Seconde Serie, t. xiv, 
1840. 
