A great many studies of the sympathetic nervous system of the fowl have been done. Tiedemann in 1810 exhibited his work on the sympathetic system under the title "Systems da la circulation du sang". He described in detail the anterior cervical ganglion^pointing out the existence of the cervical cord in the vertebral canal and indicating the carotid plexus. Emmert (1810 & 1811)\ gave a similar description of the cervical sympathetic in some birds of prey. In addition he pointed out the cardiac nerve arising from the first thoracic ganglion. Weber (1817) studied the sympathetic system of mammals, birds, amphibia and fishes. He tried to establish the relations which exist between different groups of vertebrates as well as to confirm the vagal and sympathetic systems in Vertebrates and Invertebrates. Then came Carus (1828), Sedillot (1829), Bischoff (1832), Swan (l835), Andrieu (1837), Bazin (1839), Longet (1841), Bemberg (1842), Ritzel (1843), Sappey(1847), Remak (1847), Bonsdoff (1852), Rouget (1856), Budge (1851/52), Samuel (1860), Acconci (1880), Vignal (1881), Brenner (1883) and Onodi (1884). Some of them studied the cerebro-spinal nerves in connection with the sympathetic, such as Carus, Bischoff, Swan, Bazin, Bonsdorff and Onodi. Some studied the innervation of certain organs, such as Sedillot (the action of the vagus on the digestive tube, larynx and the heart), Andrieu (the action of the vagus on the lung, voice, heart and digestive tube), Longet (the nerve of the voice), Bemberg & Ritzel (the nerves of the heart and of the tongue), Remak (the intestinal nerve), Rouget (the action of the sympathetic nerve on the eye), Vignal (the innervation of the heart), Acconci & Brenner (inferior laryngeal nerve). Rochas (1885-1887) published five papers about the sympathetic nerves of the head, describing the "tempero-lacrimal" nerve, the "plexus of Weber", the "carotid nerve", the connections between certain ganglia and the segmentai cranial nerves. He also indicated the existence of the ciliary plexus. Magnien (1885) also did good work on the dissection of the head. He indicated the existence of the Vidian nerve and the chorda tympani and the absence of the lesser Superficial petrosal nerve. Laffont (1885) did not agree with the demonstrations of the Vidian nerve and the chorda tympani given by Magnien. Marage (l887) studied the thoracic and abdominal sympathetic nerves in a great number of birds and showed the variations in different groups dissected by him. Thebault (1898) gave useful statements of the sympathetic and parasympathetic nerves in sparrows, crows and climbers. Szantroch (1927) called attention in studying the intestinal nerve of chick in both anatomy and development. Ssinellnikow (1928) studied the cardiac nerves with the staining method of Worobiew and published two papers. Both his descriptions and illustrations are useful. It is from the above mentioned references that a general idea of the sympathetic and parasympathetic nervous systems of fowls and some detailed description of certain organs has been done. There is however no systematic study with a detailed description of the entire sympathetic and parasympathetic systems of the domestic fowl. It has been the endeavor of this work to accomplish this task. Perhaps many of the problems which have been encountered could have been more easily solved and confirmed if some experimental work could have been carried out. Unhappily time is the controlling factor but it is hoped that some time in the future much of this work will be done.