560 General Notes. [May, 
describes Ofisthoplus degener, a new genus and species of snake, 
with the maxillary edentulous, except at its posterior extremity, 
where it bears a very long sulcated tooth. The same naturalist, 
in conjunction with G. Doria, describes Zodtoca atlantica from the 
Canary isles. Dr. Bean notices in the Proceedings of the United 
States National Museum a collection of birds made by him in 
the summer of 1880 in Alaska and Siberia. L. Stejneger pub- 
lishes in the same Proceedings outlines of a monograph of the 
swans, and Mr. L. M. Turner describes some variations in Lago- 
pus mutus and its allies from the Arctic regions, especially the 
western coast of Arctic America. 
PHYSIOLOGY." 
PHYSIOLOGICAL AUTOMATICITY.— Automatic and spontaneous 
movement is one of the powers of undifferentiated protoplasm, 
but it has been generally supposed that among the higher classes 
of animals all automatic and spontaneous actions are brought 
about by impulses proceeding from certain nerve cells. Thus the 
contractions of the heart, which still proceed with a definite 
rhythm after the organ is removed from the body, are supposed 
to be excited by rhythmic discharges from the nerve cells, which 
are contained within the cardiac walls. Dr. Gaskell has lately 
shown, however, that when a slender strip of muscle, perfectly 
ganglion free, is cut from the apex of a tortoise’s heart and hung 
up in a moist chamber, after the lapse of some four hours the 
strip commences to contract rhythmically and may continue thus 
automatically active for some twenty to thirty hours. The initial 
period of quiescence which follows the suspension may b 
ened about one-half if the strip of muscle be stimulated at inter- 
vals by a very feeble electrical current. “ Every part of i 
muscular tissue of the tortoise heart possesses the property 0! 
spontaneous rhythmical contraction, and the difference 1n func- 
tion between the muscular tissue of one part and that of another 
cular tissue of the frog’s ventricle this rhythmical pu gp 
THE PRODUCTION OF THE SECOND HEART SOUND. si 
twenty-third volume of Pfliiger’s Archiv, Professor Si py the 
scribes experiments which show that the sound produced y 
sudden tension of a membrane, loosely stretched across ; 
end of a vertical tube filled with water, varies in pitch 1 
1 This department is edited by Professor HENRY SEWALL, 
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