NoVKMBER 2.!, 188:). 1 



SCIENCE. 



693 



laid down with conlideiice from the examination of 

 two species. — {MUtheil. zoal. inst. iVien, v. heft 1.) 

 W. H. n. [398 



Crnstaceana. 



Trilobites from the Hamilton rocks of Penn- 

 sylvania. — Professor Angelo Heilprin lias found in a 

 small collection of inveitebrate fossils obtained from 

 the Hamilton rocks of the vicinity of Dingman's Ferry, 

 Pike county, Penn., a complete specimen and several 

 tail-pieces of Phacopsbufo, and several well-preserved 

 fragments of Homalonotus Dekayi. The determina- 

 tion of tlie.'^e species is of peculiar interest, inasmuch 

 as it had been asserted that no trace of trilobites 

 could be discovered in the rocks of this series. — 

 (Acad. nal. kc. Philad. ; meeting Oct. 30.) [399 



VERTEBRATES. 

 Origin of fat in cases of acute fat-formation. 

 — Tlie chief part of this paper by Lebedeff is taken 

 up with a discussion of the origin of the fat formed 

 or deposited in the liver in phosphorus-poisoning. 

 The author criticises at lensth the different theories 

 of the origin of fat, under both pliysiological and 

 pathological conditions. He does not admit the 

 generally accepted theory of Voit, that the fats of 

 the body form one of the products of tlie destruction 

 of proteids, and gives some calculations showing the 

 insufBciency of such an hypothesis to account for the 

 amount of fat found in the liver and other organs 

 after poisoning by phosphorus. His own view is, that, 

 under normal conditions, the animal fat is derived 

 directly from that taken into the body as food, while, 

 in pathological cases, — fatty infiltration of the liver, 

 for instance, — the fat originates from that already 

 stored up in the body. The change in the chemical 

 composition of the blood, produced by phosphorus, 

 causes the fat in the subcutaneous connective tissue 

 to pass into the blood, whence it cannot be removed 

 on account of the diminished supply of oxygen, 

 which is one of the results of phosphorus-poisoning, 

 and therefore accumulates in the liver. Lebedeff has 

 shown in a former paper, that when a dog is starved 

 until all fat has disappeared from its tissues, and is 

 then fed on foreign fats — linseed-oil, for example — 

 and some proteids, there is a large accumulation of 

 the strange fat in the body. Similar experiments 

 were again made, with the addition that the animal 

 was afterwards poisoned with phosphorus. Chemical 

 analysis of the fat of the liver in such cases showed 

 that it also, like the subcutaneous fat, contained a 

 large proportion of the foreign fat. This fat could 

 not have resulted from the destruction of proteids 

 of the body, but must have been derived from fat 

 already stored up in the body before poisoning, 

 especially the subcutaneous fat. Lebedeff also made 

 chemical analyses of the fats contained in the milk 

 of the cow, woman, and rabbit, and compared them 

 with the fats of other parts of the body. He finds 

 that the ' fat of milk has no analogue in the body,' 

 and consequently is not derived directly from these 

 fats. He does not believe, however, that this fat re- 

 sults from proteid metamorphosis. The increase in 



the fat of milk, that lakes place after feeding with 

 meats, is owing, he thinks, to the fact that the albumi- 

 nous material taken serves to emulsify the fats, and 

 thus insures an easier passage from the blood. He 

 comes to the conclusion that the fat of milk is di- 

 rectly influenced by the nature of the fat taken as 

 food, and gives the results of some experiments de- 

 monstrating this fact. With regard to the origin of 

 the milk-fat, his statements arc not very satisfactory. 

 It is derived directly, in the first place, from the fat 

 of the mammary glands, with which it agrees in 

 composition. This, in turn, is formed, he thinks, 

 from the fats taken as food, or, in the case of starva- 

 tion, from the fats stored up in the body. — [Pfliiger's 

 arcltiv, xxxi. 0. ) w. H. n. [400 



UammaU. 

 Vaso-dilators of the lo'wer limb. — In previous 

 papers. Dartre and Morat have shown that the view 

 which was generally held of the distribution of the 

 vaso-motor nerves — that the vaso-constrictors take 

 their course through the sympathetic, the vaso-dila- 

 tors through the cerebro-spinal nerves — is not true 

 for the cervical sympathetic. They succeeded in 

 demonstrating in it the presence of vaso-dilator 

 nerves for the cheek, lips, etc. In the present paper 

 they give the results of similar investigations upon 

 the lower segments of the sympathetic, and the vaso- 

 motors of the lower limbs. In order to estimate the 

 v<aso-motor effects, two methods were used. A ma- 

 nometer, or sphygmoscope, was connected with the 

 femoral artery below the origin of the profunda; 

 and, at the same time, the color-changes in the skin 

 of the toes were noticed. Young dogs with little or 

 no pigment on the feet were used. They first inves- 

 tigated the effect of stimulation of the peripheral end 

 of the divided sciatic. In all cases the manometer 

 showed a rise of arterial pressure, indicating that 

 vaso-constriction had taken place; but, together with 

 this general vaso-constriction of the blood-vessels, 

 it was found, in some cases, that the balls of the toes 

 were congested, showing local vaso-dilatation. If, 

 instead of the sciatic, the abdominal sympathetic 

 was divided at the level of the fourth lumbar gan- 

 glion, and the peripheral end stimulated, the same 

 result was reached. — a general constriction of the 

 arteries, together with a local dilatation of the skin 

 of the toes. The latter phenomenon, as in the first 

 experiment, was not constant. When the sympa- 

 thetic was stimulated still higher, just below the dia- 

 phragm, the manometer gave a rise of pressure; but 

 the dilatation of the vessels of the toes was more evi- 

 dent, and occurred in all cases. The interpretation 

 they give to their experiments is, that va'so-dilator 

 as well as vaso-constrictor fibies run in the sympa- 

 thetic to the lower limbs; the vaso-constrictors pre- 

 dominate: hence the general rise of blood-pressure 

 in the limb. The fact that the vaso-dilator effects 

 are always obtained when the lower part of the tho- 

 racic sympathetic is stimulated, while in stimulation 

 of the lumbar sympathetic and the sciatic this phe- 

 nomenon is very inconstant, means, they think, that 

 the vaso-dilators terminate, in part at least, in the 



