November 22, 1894] 



NATURE 



61 



body takes place at different stages. At first the twist is 

 almost exclusively confined to the fore part, but when this 

 amounts to about iSo degrees the rear part of the animal 

 turns. M. Marey is of the opinion that an inspection of 

 the figures altogether excludes the idea that the animal 

 uses the hands that let it go as a fulcrum by means of 

 which a movement of rotation is obtained. The first few 

 images in each of the two series show that at the begin- 

 ning of the fall the cat exhibits no tendency to turn 

 either one side or the other. 



As to the hypothesis that the resistance of the air 

 affords a means of turning, this also appears to be inad- 

 missible ; because, on account of the tumbling motion 

 of the animal, if this resistance had an appreciable 

 effect, it would produce a rotation in the opposite direc- 

 tion to that observed. 



M. Marey thinks that it is the inertia of its own mass 

 that the cat uses to right itself. The torsion couple 

 which produces the action of the muscles of the vertebra 

 acts at first on the forelegs, which have a very small 

 motion of inertia on account of the front feet being fore- 

 shortened and pressed against the neck. The hind legs, 

 however, being stretched out and almost perpendicular 

 to the axis of the body, possesses a moment of inertia 

 which opposes motion in the opposite direction to that 

 which the torsion couple tends to produce. In the second 

 phase of the action, the attitude of the feet is reversed, 

 and it is the inertia of the forepart that furnishes a 

 fulcrum for the rotation of the rear. 



BIOLOGY IN THE UNITED STATES— A 

 PROSPECT} 



'T^HIS volume is slightly larger than its predecessor 

 •'■ published in 1S91, and is an advance upon it in 

 the number and class of its illustrations. During the 

 interval of publication of the two volumes, much of the 

 work announced in the first one has appeared in full ; 

 and the present one shows that although, perhaps, 

 more might be made of the resources of the Wood's 

 Holl Laboratory and its rich surroundings by a better 

 appreciation on the part of the scientific public, there 

 is no falling off in either the energy or enthusiasm of its 

 founders and chief supporters. The ten lectures reported 

 in this volume are chiefly special ones, given by investi- 

 gators who undertake to review their chosen field of 

 labour, and to set forth the results of their own inquiry 

 — it being an avowed object to bring forward unsettled 

 problems of the day, and discuss them freely. The 

 lectures are published for the first time, with the exception 

 of that which is the most striking of the series and one 

 of the most remarkable contributions to recent biological 

 literature, viz. Prof. C. O. Whitman's thesis on " The 

 Inadequacy of the Cell-theory of Development,"originally 

 read before the Zoological Congress of the World's 

 Columbian Exposition, and already reprinted in the 

 Journal of Morphology. Prof. Whitman's work in this 

 department dates from his inaugural dissertation for the 

 degree of Doctor of Philosophy in the University of 

 Leipzig, dealing with the embryology of Clepsine, in 

 which he laid the foundation of his now famous telo- 

 blast theory. The researches which this essay has 

 provoked rank foremost in interest among all those 

 recently devoted to the study of the germinal blastemata. 

 No one has more assiduously followed up Prof. Whit- 

 man s suggestive lines than Prof. E. B. Wilson, whose 

 lecture on '• The Mosaic Theory of Development " ranks 

 first in order in the present volume. His recent work on 

 the cell-lineage of Nereis is second only to that of Whit- 

 man in interest and importance. His present treatise 



'* Biological Leclures delivered at the Marine Biological Laboratory of 

 Wood's Holl." Vol. li. (Boston: l'..nn and Co., 1894 ) 



NO. 1308. VOL. 51] 



is a review of the embryological work of the last decade 

 in its bearing upon the biogenetic law. Prof. Whitman 

 would seek the secret of organisation in ultimate elements 

 of living matter "for which idiosovics seems an appro- 

 priate name " ; Prof. Wilson, that of differentiation 

 during development in the interaction of the embryo-cells. 

 There next follows a lecture by Dr. E. G. Conklin, on 

 "The Fertilisation of the Ovum," apropos of the author's 

 researches into the development of the marine gas- 

 teropod Crcpidula plana. 



Lecture iii. is by Prof. Jacques Loeb, " On some 

 Facts and Principles of Physiological Morphology.'' 

 He first considers the question of "heteromor- 

 phosis" or substitution of organs, as illustrated (under 

 the maltreatment of Antennularia') by the develop- 

 ment of new roots and apices in relation to gravi- 

 tation, and by root formation at points of contact 

 with solid bodies, in Margeliss and other hydroids. He 

 shows that it is possible to obtain roots and polyps at 

 will over various and interchangeable areas, in direct 

 response to modified conditions of growth. There fol- 

 lows this a lecture by Prof. Ryder on " Dynamics 

 in Evolution," which is suggestive but imaginary. 

 New terms and statements of probabilities it does 

 contain, but new facts it does not. Its most interest- 

 ing portions are those relating to surface tension in 

 its probable bearings on protoplasmic activity ; but it 

 appears to us rather more sensational than sound. The 

 comparison of the behaviour of a contracted smoke-ring 

 to an amccba in motion is suggestive, perhaps in a sense 

 not intended by the author. Dr. Watasu follows with a 

 dissertation " On the Nature of Cell Organisation." 



Lecture vii. is a very welcome one, by Dr. Howard 

 .■\yers, on Bdellostoma Dombeyi, apropos of its author's 

 work upon the comparative morphology and physiology 

 of the vertebrate ear. He deals at some length with the 

 habits of the animal, and adduces additional evidence 

 for the belief in the primitive, as distinguished from the 

 alleged "by parasitism degenerate" nature of the 

 cyclostomi which has been so generally accepted. 

 He records the fact that the gills vary in number from 

 eleven to thirteen on either side, in individuals from 

 diflerent localities ; he regards this variation as in- 

 dicative of suppression, and the numerically highest 

 as the most primitive type, instituting comparisons 

 with the larval AmpJiioxus which appear to us 

 unsound. We welcome his conclusion that the numerical 

 variation of the gills has nothing to do with the forma- 

 tion of the ductors cesophago-cutaneus. He pro- 

 visionally argues that Bdellostoma is unique in the 

 fact that geographical distribution has had little or 

 no effect upon its anatomical structure ; and proposes to 

 recognise but a single genus and species of this form, in a 

 manner curiously mindful of his notorious attempt to 

 similarly unite Protopterus and Lepidosircn. Not even 

 allowing for the possibility that the hitherto ac- 

 cepted species of Bdellostomas may be distinct in their 

 habits as well as taxonomically, this proposal ap- 

 pears to us premature, and systematic ichthyo- 

 logists will certainly not acquiesce to it. In common 

 with most subsequent investigators, he finds himself 

 unable to confirm Beard's alleged discovery of calcified 

 teeth in these creatures. He regards Beard's '' bone ' as 

 " much hardened horn, produced by the methods used in 

 preparation.' This we cannot accept. The cells of 

 Beard s " calcified teeth," although uncalcified, are 

 mesoblastic, and the structure described by him as an 

 " enamel cap " (whatever it may be) certainly does appear 

 in individual sections. He finds that hermaphrodites 

 occur even among old individuals ; but while examples 

 possessed of ripe ova and spermatozoa may be forth- 

 coming, he finds them to be rare, and concludes 

 that preponderance of males is the ordinary con- 

 dition. His observations upon the olfactory organ 



