184 • SUMMARY OF CURRENT RESEARCHES RELATING TO 



the spinal ganglion cells of the rabbit and the pigeon, and corroborates 

 his previous results. He suggests that trophocytes absorb substances 

 from the blood in the immediate vicinity of the spinal ganglion cells, 

 and store them in their cell-substance in the form of material which is 

 darkened by osmic acid. From the trophocytes the material may pass 

 into the intracellular processes of the trophospougia, and has to do with 

 the constitution of the tigroid substance. The canaliculi which some- 

 times take the place of the granular threads of the network are not 

 artefacts. They become more numerous after prolonged and energetic 

 stimulation. 



Structure of Adrenals of Amphibians.* — T. B. Magath cor- 

 roborates in Rana pipkns and R. cJamata the observation of Patzelt and 

 Kubik on R. esciilenia that there are two kinds of cells in the adrenal 

 glands. There is an epithelial portion composed of the common lipoid- 

 containing cells, and among them large granular acidophilous cells. 

 There is, secondly, a chromaffine portion. Acidophilous cells appear in 

 the adrenals all the year round, and Stilling's term " summer cells " is 

 inappropriate. In addition to those Anura and Urodela noted by 

 Patzelt and Kubik, there are no acidophilous cells in Spelerpes hilineatus, 

 Flethodim glutinosus, and Acris gryllus. The presence of acidophilous 

 cells in the adrenals of the three species of Rana named above may 

 indicate close relationship and similar metabolism. . 



Ampullae of Lorenzini in Dogfish.f — H. E. Metcalf has made an 

 experimental and histological study of the ampuUte of Lorenzini in 

 Acanthias vulgaris, and finds that they are primarily sense organs. They 

 have a secretory function in so far as it is necessary to keep up the 

 supply of mucus in the ampullae and their ducts. This need is small, as 

 there is little loss. The ampullte respond to the stimulus of pressure, 

 and if currents of water impinge on some of the ampulla? more forcibly 

 than on others, the fish may get some indication of the direction of 

 the source of the stimulus. The ampullse may also serve as depth- 

 indicators. The minute structure of the duct and ampulla is described. 



The number of ampulla varies from 1,200 to 1,900— about 500 

 dorsal, 900 ventral and anterior to the mouth, and 200 lateral and 

 posterior to the mouth. There are none posterior to the first gill-slit. 

 There is no addition to the number after birth. 



c. G-eneral. 



Transmission of Tropical Diseases. :J— J. W. W. Stephens discusses 

 the mode of transmission of some tropical diseases. Thus, malarial 

 parasites are spread by Anopheline mosquitoes. Attention is directed to 

 a recent case of malaria from Eomney Marsh, to Indian villages which 

 have no malaria though in the midst of intensely malarial districts, and 

 to the reservoir of malaria aff'orded by native children who do not seem 

 to be much the worse. Yellow fever, the organism of which is still 



* Trans. Amer. Micr. Soc, xxxiv. (1915) pp. 154-8 (2 figs'.). 



t Trans. Amer. Micr. Soc, xxxiv. (1915) pp. 131-46 (2 pis. and 4 figs.). 



X Proc. Trans. Liverpool Biol. Soc, xxix. (1915) pp. 3-19. 



