ZOOLOGY AND BOTANY, .MICROSCOPY, ETC. 611 



what dorsally to the central canal at a few parts of the median area of 

 the cord ; and (3) some isolated cells, which are described. 



Awanting in the fish, but present in man, are (1) the sympathetic 

 cell-groups ; (2) the so-called Clarke's pillar ; and (3) the other large 

 cells of the dorsal cornu of the grey substance. 



Muscles of Lamprey.* — P. Schiefferdecker has made an elaborate 

 study of the trunk-muscles of Petromyzon fluviatilis as regards the 

 structure of the fibres, the nuclear relations, and the sarcolemma. There 

 are various degrees of differentiation, at least three different kinds : the 

 " parietal " fibres of the trunk, the " central " fibres of the trunk, and the 

 muscles of the head. The " parietal " fibres of the trunk correspond 

 essentially to those of higher animals, diverging only in shape, most of 

 them being four-sided prisms. The " central " fibres are large muscle- 

 plates, very far from the usual type, and fenestrated. The " central " 

 fibres have a sarcolemma, but no perimysium ; the " parietal " fibres 

 have both. The latter are poor in sarcoplasm, the former very rich. 



The author enters into the subject in minute detail — his summary 

 alone occupying over six pages — and draws from his study a number of 

 conclusions as to muscle-fibres in general. One may regard a differ- 

 entiated cross-striped muscle-fibre of a Vertebrate as a syncytium of 

 muscle-cells, surrounded by a sarcolemma, which is of the nature of a 

 " cell-membrane." 



Survival of Isolated Leucocytes. f— J. Jolly has been able to keep 

 leucocytes from the frog's blood living and mobile in vitro for a year. 

 They were kept in sealed glass tubes at about zero until May, June, and 

 July, 1911, when the temperature rose to +5°. 



c. General. 



Action of Radium Radiations on Blood.} — Helen Chambers and 

 S. Russ have studied the action of radium radiations upon some of the 

 main constituents of normal blood. Red blood-corpuscles are hremolyzed 

 by the action of the a-rays, and oxy-hgemoglobin is converted into met- 

 hamioglobin. Leucocytes undergo marked degenerative changes when 

 subjected to a-rays. During the process of clotting, leucocytes appear 

 to move away from an a-radiated region. This movement has been 

 attributed to changes found to occur in the surface tension of blood 

 serum when radiated. The specific properties of opsonin and hemolytic 

 complement are lost when serum is exposed to a-rays. The progressive 

 changes caused by these rays indicate the separate identity of opsonin 

 and complement. The /3-rays and y-rays have yielded negative results in 

 analogous experiments. 



Sleeping and Waking.§ — Ch. Bouchard re-states his theory that a 

 narcotic substance produced during the activity of waking hours, and 

 experimentally demonstrable in the urine, leads to sleep. During sleep, 

 on the other hand, there is formed an excitatory ("convnlsivaiite") 



* Arch. Mikr. Anat., lxxviii. (1911) Festschrift Waldeyer, pp. 422-95 (2 pis. 

 and 3 figs.). t C.B. Soc. Zool., lxxi. (1911) pp. 147-S. 



X Proc. Roy. Soc, Series B, lxxxiv. pp. 121 36 (8 figs.). 

 § Comptes'liendus, clii. (1911) pp. 504-5. 



