24 SUMMARY OF CURRENT RESEARCHES RELATING TO 



regards the former, he is absokitely opposed to the view of Metchnikoff 

 regarding the role of phagocytes. There is a complete histolysis of the 

 tissues, with probable elimination in part and modification for nutrition 

 of the remainder by the liver and spleen. Regarding the intestine, 

 there are macroscopic modifications consisting in peristaltic contraction 

 producing a reduction of calibre and length of the small intestine, with 

 microscopic modifications. These last are essentially a desquamation of 

 the striated layer of cells of the larval epithelium, and the formation of 

 the adult epithelium at the expense of the basal cells, which during this 

 regeneration pass through a sort of syncytial stage. The phenomena 

 observable in the stomach consist simply in the throwing off of the 

 superficial layer of epithelium. 



Trapezium of Rabbit.*— N. Antoni and A. Bjork have found, with 

 the aid of the new neuro-fibrillar method of Cajal, that the neurites 

 ending in the cell nucleus of the trapezium and associated ganglion-cells 

 show in their mutual relations a different appearance according to age. 

 In the trapezium of new-born animals they find peculiar intra-cellular 

 formations, which show as black slightly branched threads, with a 

 tendency to form a network or short rigid rods. They conclude that 

 these structures are probably of a nervous nature. 



Regeneration of Nerves.f — F. "W. Mott, W. D. Halliburton, and 

 A. Edmunds describe several series of experiments with the nerves of 

 monkeys and cjits. They have obtained strong evidence in favour of the 

 Wallerian doctrine, that new nerve-fibres are growths from the central 

 ends of divided nerve-trunks. Regenerated fibres, after being again 

 severed from the central nervous system, always degenerate in a peri- 

 pheral direction only. The nerve-sheath has a phagocytic and nutri- 

 tive function ; at the central end of a severed nerve this nutritive 

 function is effective in providing actively for the lengthening of the 

 axis cylinders. At the peripheral end, unless the axons reach it, there 

 is no real new formation of nerve-fibres. If, however, the axons reach 

 the peripheral segment, the work of the neurilemmal cells has not been 

 useless, for they provide the supporting and nutritive elements necessary 

 for its continued and successful growth. All the facts made out by the 

 authors are readily explicable on the theory that the nerve-fibres are 

 growths from the central ends of divided nerves. 



Structure of Mammalian Lung.| — Franz Eilhard Schulze returns 

 to a subject which he discussed in 1871, when he described a tree-like 

 branched canal-system of ducts beset with alveoli, and ending in blind 

 saccular infundibula or air-sacs. He discusses the size of the alveoli 

 in various mammals, the number of alveoli, and the size of the entire 

 respiratory surface (about 30 square metres for man, 150 million alveoli ; 

 about 43 square metres for the dolphin, 437 million alveoli). He 

 describes the gaps in the partition wall of the alveoli, the capillary net- 

 work of the alveoli, and so on. 



* Anat. Anzeig., xxix. (1906) pp. 300-7 (13 figs.). 



t Proc. Roy. Soc, Series B, Ixxviii. No. B 525 (1906) pp. 259-83 (1 pi. and 5 figs.). 



X SB. k. Preuss. Akad. Berlin, 1906, pp. 225-43 (7 figs.). 



