834 



SCIENCE. 



[Vol. II., No. 47. 



medullary sheath as the axis-cylinder. Correspond- 

 ing nerve-fibres are found, which preserve their indi- 

 viduality, notwithstanding the filaments they give 

 off from the axis-cylinder, which can be followed to 

 the gauglion-cells. The structures are supposed to 

 belong to the sensory system. In the motor system 

 the individuality of the process or of the fibre is 

 lost in the gray substance, completely breaking up 

 into filaments which enter into the formation of a 

 diffuse network. It would appear, then, that the 

 motor process breaks up into filaments, forming a net- 

 work, from which spring the other filaments, which 

 unite to form the motor axis-cylinder. The network 

 really receives filaments also from the sensory pro- 

 cess and fibres; so that it may be regarded as a fun- 

 damental nervous plexus, both sensory and motor, 

 by means of which each fibre communicates, not 

 with a single cell, but with large groups. The ten- 

 dency is towards extended, not restricted, communi- 

 cations; and there is no anatomical basis for the 

 assumption of the isolated transmission of peripheral 

 nervous impulses to hypothetical limited cellular in- 

 dividualities. This investigation, therefore, lends 

 no support to the theory of cerebral localization. 

 Deiter's process is characterized from its origin by 

 its greater homogeneousness, its hyaline aspect and 

 smooth surface, while the protoplasmatic processes 

 are granular. 



Golgi has also studied the histology of the cortex 

 cerebri, especially to compare the anterior with the 

 occipital convolutions. Meynert's plates, and divis- 

 ion of the cortex into five layers, he thinks, do not 

 agree with the reality. Golgi distinguishes three 

 forms of ganglion-cells, — pyramidal, fusiform, and 

 globular (or polygonal with roimded angles). He 

 distinguishes three layers of about equal thickness. 

 The superficial layer is formed almost exclusively by 

 rather small pyramidal cells; the middle layer has, 

 for the most part, larger pyramidal cells ; while in the 

 deep layer the fusiform cells prevail, and the globular 

 cells, which occur throughout the cortex, are here 

 most abundant. The largest pyramidal cells extend 

 through the whole thickness of the cortex. Such is 

 .the organization of the gyrus centralis anterior (fron- 

 "talis ascendens). The organization of the superior 

 occipital convolution is similar, except that the deep 

 layer contains the globular cells almost exclusively. 

 There are no anatomical features to indicate that the 

 anterior convolutions are motor, the occipital sensory, 

 as Hitzig and others have maintained. " The specific 

 functions of the different cerebral zones do not 

 depend on the organization of these zones them- 

 selves, but on the specific character of the peripheral 

 organs which are connected with the fibres entering 

 orleaving the zones in question.'' — (Arch. ital. biol. 

 iii. 285.) c. s. M. [578 



Buds. 



Development of the heart — Assaky maintains, 

 1°, that the heart arises in the chick as a double tube, 

 as may be seen before the differentiation of the third 

 protovertebra; 2°, the myocardium is constituted 

 from the first by a network of anastomosing cells; 

 the muscular fibres arise by endocellular generation ; 



3°, the muscle-cells are derived from amoeboid cells 

 [i.e., are mesenchymal]. — (Comptes rendux, xcvii. 

 183.) c. s. M. [579 



Plumages of the stone-chat. — Messrs. Butler, 

 Fielding, and Reid seem finally to have solved the 

 variations in plumage of this interesting bird. Ac- 

 cording to them, there are nine different stages easily 

 recognizable. We note with satisfaction that the 

 theory of hybridization seems to be done away with. 

 - {Ibis, 1883, 331.) J. A. J. [580 



The influence of quinine upon heat-dissipa- 

 tion and heat-production. — In a late article by 

 Wood and Keichert (Joxirn. of physiol., iii. 321), the 

 authors make the statement that quinine increases 

 both heat-production and heat-dissipation, though, 

 on the average, the percentage of increase of heat- 

 dissipation largely exceeds that of heat-production. 

 A desire to test the accuracy of these results has led 

 Amtz to make a similar series of experiments. To 

 measure the relative amount of heat-dissipation from 

 the skin, he made use of a porous wooden cap, lined 

 with felt, which could be applied to any part of the 

 body. The temperature within the space thus en- 

 closed was registered by a delicate thennometer. 

 Any increase in the loss of heat through the skin 

 would be shown, therefore, by the thermometer. 

 Experiments were made upon men and rabbits in a 

 normal healthy condition, the general results of 

 which show that no increase in heat-dissipation fol- 

 lows the injection of quinine. To explain the con- 

 tradiction existing between his own and Wood's 

 results, he supposes that the doses used by the latter 

 were too large for the animal (dog) experimented 

 upon ; and the increase in heat-dissipation was prob- 

 ably owing to the animal's struggles and attempts to 

 vomit. Two experiments that he made upon dogs, 

 using the same dose as that given by Wood, tend to 

 support this explanation. To determine the effect of 

 quinine upon heat-production, spirometric observa- 

 tions were made upon normal rabbits, and rabbits 

 suffering from septic fever, the amount of oxygen 

 absorbed being taken as an indication of the oxida- 

 tions going on in the body. In normal rabbits, qui- 

 nine was found to have no effect upon the amount of 

 oxygen consumed; while, in febrile animals, it caused 

 a diminution in the oxygen-consumption. The au- 

 thor's conclusion, with regard to the anti-pyretic 

 action of quinine, is, that it acts in the first place in- 

 directly by destroying the organisms n^hich give rise 

 to the fever, and, in the second place, directly dimin- 

 ishes the oxidations in the tissues of the body. — 

 (Pffuf/er'N «)-c/aii, xxxi. 531.) w. ii. n. |581. 



Action of carbon dioxide and oxygen upon 

 the mammalian heart. — The present paper by Klug 

 forms an extension of some previous work of the 

 same nature on the frog's heart. His experiments 

 were made upon dogs anaesthetized by means of mor- 

 phia, and made to breathe in an atmosphere contain- 

 ing different percentages of carbon dioxide or oxygen. 

 With regard to the action of carbon dioxide he finds, 

 in accordance with previous observers, that it acts as 



