143 
The investigation on the human subjects was carried out on 40 
post-mortem examinations at the Manchester Royal Infirmary by 
the kind permission of Professor LORRAIN SMITH. 
In the naming of the various animals I have had much help from 
Mr. J. R. Harpy of the Manchester Museum, to whom I would 
express my grateful thanks for his unfailing courtesy and assistance. 
Results. 
So far as can be ascertained by the foregoing research the follows 
ing conclusions are justified: 
(1) There is no tendency toward the prefixing of the hinder end of 
the brachial plexus in man as compared with other mammals 
generally (except the cercopithecidae). 
Modifications entailed by the erect posture are not found 
in the nerves but in the skeleton. 
(2) In the cercopithecidae, the second dorsal nerve as a rule con- 
tributes a large branch to the brachial plexus. 
(3) Great individual variation is found throughout the mammalian 
series in the communication given by the second dorsal nerve 
to the brachial plexus. 
This variation is evidenced in the following manner: 
1. Presence or absence of the communication. 
2. Size of the nerve. 
3. Relation to the sympathetic chain. 
(4) The communication may be composite in character and may 
consist of both spinal and sympathetic fibres. _ 
(5) The communication is of important physiological significance in 
the production of pressure symptoms on the lowest brachial 
trunk. 
References. 
(1) CunnineHam, Note on a connecting twig between the anterior divisions 
of the first and second dorsal nerves. Journ. Anat. Phys., Vol. XI, 1877, 
p- 539. 
(2) BırmineHam, The Nerve of Wrisserc., Journ. Anat. Phys., Vol. XXX, 
1896, p. 61. 
(3) Erzior Smiru, Rare Nerve and Muscle Anomalies, Journ. Anat. Phys., 
Vol. XXIX, 1895, p. 84. 
(4) Purves STEwART, Diagnosis of Nervous Diseases, Ist Edit. 1906. 
