ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



17 



concluding from what has been seen in one class of vertebrates as to 

 their structure in another. He figures and re-describes the cells of 

 the spinal ganglia in the torpedo, frog, guinea-pig, and dog ; those of 

 the gasserian ganglion in the pike, frog, triton, and dog. Bipolar 

 cells were seen in fishes only, unipolar cells in batrachians and mam- 

 mals; reptiles and birds were not investigated. Arnold's spiral 

 fibre is an optic phenomenon due to folding of the sheath. There 

 is still no proof that the cells of the same ganglion are in any way 

 mutually connected, Apolar cells are more common than is supposed, 

 occurring less often in old or higher than in young or lower verte- 

 brates ; they are never isolated, but each rests in one sheath with a 

 unipolar cell. The " polar nucleus " of Courvoisior belongs not to 

 the proper ganglionic corpuscle, but to the same category as the other 

 (connective-tissue) nuclei of its sheath, whose endothelium Fraentzel * 

 has already described. 



Decompound Gastric Glands.t — Leydig has described the peculiar 

 aggregated gastric glands of the beaver and southern manatee. In the 

 latter, especially, they show an exquisite structure, figured by him in 

 his admirable ' Lehrbuch.' These " decompound " glands, so rare 

 among mammals, are known to be very common in birds. They pre- 

 sent various degrees of aggregation, and in this respect are most 

 highly modified in the Eheas, as already stated by Professor Owen. 



The huge gastric gland of the American Bhea is now adequately 

 described and figured by M. E. Eemouchamps. He resolves it into 

 primary, secondary, and tertiary utriculi, the arrangement of which 

 varies in different parts of the gland, and recalls the structure of 

 diverse glandular types among other vertebrates. The secondary 

 utriculi are further distinguished according to the presence, absence, 

 or incomplete development of a canal. The naked epithelial cells of 

 the primary (or ultimate) utriculi, forming a single layer, are all of 

 the same structure. Towards the proximal ends of these utricles, the 

 accumulation of their secretion, including debris of the cells, gives 

 rise to appearances the nature of which M. Eemouchamps discusses. 

 Finally, with the aid of diagrams, he explains and extends the classifi- 

 cation of the gastric glands of birds proposed by Bergmann in 1862 

 (' Eeichert und Du-Bois-Eeymond's Archiv '). 



Regeneration of Spinal Cord.| — Prof. M. Masius replies to 

 various criticisms of his previous researches, in conjunction with Van- 

 lair, on repair of the mutilated spinal cord in the frog. He has since 

 extended these investigations to dogs, and compares his results with 

 those of other workers, more particularly Eichhorst and Naunyn. 



Puppies between three and four months old had a segment of the 

 cord about four millimetres long completely removed in the region of 

 the fifth lumbar vertebra. In dogs thus treated the hinder limbs are 

 useful as before, but the sphincters lose their power, so that the 

 urine and fgeces cannot be retained, and the tail also is quite paralyzed. 

 Amendment of these symptoms began six weeks after the operation. 



* Virchow'g Arclaiv, xxxviii. p. 554. 



t Arch, de Biol., i. (1880) pp. 583-94 (1 pi.). J Ibid., pp. G96-717 (1 pi.). 



Ser. 2.— Vol. 1. C 



