. The American journal of anatomy. taneous branches of the fourth and fifth intercostal nerves supply overlappingareas, anastomoses between the nerve branches revealed by dissection are bundle of fibres constituting a nerve may cross over or through another nervewithout real anastomosis of the two trunks. Charles Russell Bardeen 237 A study of the development of the peripheral cutaneous nerves leadsto the belief that some sort of stimulus to growth is exerted upon thenerves by areas lacking innervation. In Fig. 5 numerous areas may beseen into which nerve branches proceed from sev
. The American journal of anatomy. taneous branches of the fourth and fifth intercostal nerves supply overlappingareas, anastomoses between the nerve branches revealed by dissection are bundle of fibres constituting a nerve may cross over or through another nervewithout real anastomosis of the two trunks. Charles Russell Bardeen 237 A study of the development of the peripheral cutaneous nerves leadsto the belief that some sort of stimulus to growth is exerted upon thenerves by areas lacking innervation. In Fig. 5 numerous areas may beseen into which nerve branches proceed from several directions. Kiihns interesting experiments on the regeneration of nerves in thedorsal cutaneous region of tlie frog have an important bearing oh themode of forward growth of nerves. When an area of the skin was de-prived of its nerve supply b\ cutting two or three main nerve-trunks dis-tributing branches to it, he found that from nerves in the neighboringregions new nerve-fibres extended into the deprived area. In this inner-. FiG. .5. A portion of the nerve-plexus formed by the lateral cutaneous branchesof the dorsal divisions of two thoracic nerves of a pig embryo 4 cm. long. Tr. Maintrunk of each nerve. 88 diam. vation new nerve-paths and peripheral plexuses not corresponding withthe old were often formed, or the growth of the new fibres showed noregular order. This last was especially true of nerve-fibres arising fromthe central ends of the cut nerves. During end)ryonic development nerve-fibres derived from very difl^er-ent sources and destined for a different ultimate distribution often takecommon paths for a part of their course. Good examples of this maybe seen in the distribution of the vaso-motor nerves and in the relationsentered into between the trigeminal nerve, the facial nerve and the cervi-cal nerves. Popowsky has called attention to the development of anas-tomoses between the fifth and seventh cranial nerves. A given cutaneous area with the nerves distribut
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