982 
For substances for which the size of the molecules in the vapour 
and the liquid phase is equal or about equal f is about 3, so that 
the value 4,221 indicates that for the violet phosphorus the average 
size of the molecules in the coexisting vapour and liquid phases is 
different. 
A discussion of the vapour tension line of the white phosphorus 
will be reserved for another paper. 
Anorg. Chem. Laboratory of the University. 
Amsterdam, Dec. 24, 1914. 
Anatomy. — “On the termination of the efferent nerves in plain 
muscle-cells, and its bearing on the sympathetic (accessory) 
innervation of the striated muscle-fibre. By Prof. J. Boek. 
(Communicated in the meeting of December 30, 1914). 
In recent years it has been demonstrated for a large number of 
different types of striated muscle-fibres of vertebrates, that the motor 
nerve-endings, which carry the nervous impulses towards the muscular 
libres, are hypolemmal in position, i.e. are not lying outside the 
sarcolemma of the muscle-fibres as maintained by most of the earlier 
observers, but pass through the sarcolemma, which becomes conti- 
nuous with the neurilemma, penetrate into the sarcoplasm of the 
muscle-fibre, which is considerably thickened as the site of formation 
of the end-organs, and it was further assumed, that here the neuro- 
fibrillar expansion of the motor nerve-ending is directly continuous 
with a reticulum in the sarcoplasm, the so-called ‘periterminal 
network” *). | 
At the same time it was shown, that beside the common motor 
nerve-ending there must be distinguished another afferent nerve- 
ending on the striated muscle-fibres of vertebrates, which may either 
be found imbedded in the same granular bed of sarcoplasm or “sole” 
of the motor endorgan of KiiHNE, or reaching the muscle-fibre inde- 
pendent of this, but always having a hypolemmal position in the 
muscle-fibre®). This “accessory” nerve-ending is always found at 
the end of a non-medullated nerve-fibre. As it could be shown, that 
these accessory nerve-endings did not degenerate after the cutting 
of the efferent muscle-nerve near the place of exit from the central 
nervous system, before the entering of the sympathetic nerve-fibres 
1) J. Boeke. Beiträge zur Kenntuiss der motorischen Nervenendigungen. I. II. 
Internat. Monatschr. f. Anatomie und Physiotogie Bd. 28. 1911. 
2) J. Boeke. Die doppelte (motorische und sympathetisch) efferente Innervation 
der quergestreiften Muskelfasern. Anat. Anzeiger. 44. Band. 1913, 
