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THE POPULAR SCIENCE MONTHLY 



ten iron. The latter fact shows simply that 

 solid iron, when at a high temperature, ap- 

 proaching its melting-point, is less dense 

 and lighter than molten iron, which fact 

 again implies that molten iron must undergo 

 a rapid expansion in the moment of its so- 

 lidification. The extent of this expansion 

 is, however, less than that of the subse- 

 quent contraction in cooling, so that the 

 cold iron is again denser than the molten 

 iron." 



Growth of Plants within the Egg. 

 Prof. Panceri's observations and experi- 

 ments on the production, of eryptogamic 

 vegetation in eggs are interesting, from 

 their bearing on the question of spontaneous 

 generation. At Cairo, an ostrich-egg was 

 given him which was still fresh, the air- 

 space having not even been formed. He 

 soon, however, noticed the appearance of 

 dark blotches within the shell, and, having 

 broken it to ascertain the cause, he found 

 that they were produced by the growth of 

 minute fungi. The partisans of spontaneous 

 generation look on such cases as that as an 

 argument in their favor, supposing the shell 

 of an egg to be quite impermeable to germs 

 derived from without. Panceri, on the con- 

 trary, has found that the unbroken shell of 

 an egg is permeable to liquids, and that 

 these may introduce germs into the interior. 

 He has, in fact, actually inoculated uncon- 

 taminated eggs with a fungus obtained from 

 the interior of one in which it had made its 

 appearance in a way seemingly so myste- 

 rious, and which he had cultivated in egg 

 albumen. 



Bnxley on the Cell-Theory in Physiol- 

 ogy. In seconding a motion of thanks to 

 Prof. Redfern, President of the Biological 

 Section of the British Association, Mr. 

 Huxley said that the promulgation of the 

 cell-theory had as great an effect upon the 

 physiological world as the French Revo- 

 lution had on the world of politics. Re- 

 ferring to the doctrine promulgated by 

 Schwann and Schleiden, he said that un- 

 derneath that doctrine there lay the idea 

 which had been established by every further 

 observation, and which remained unassail- 

 able, viz., that the living body was not a 

 simple continuous whole, and its action was 



not the action of a unity, but that it was 

 made up of a multitude of parts, which lived 

 a (/wasi-independent life ; and that the body 

 of a man was made up of an enormous mul- 

 titude of small living particles, each of which, 

 though subordinated and kept together by 

 means referred to by Prof. Redfern, led a 

 ^wasi-independent life, as did the cells of 

 the organic elements of a plant. It was, in 

 fact, the application to animal-structure of 

 the idea which had been previously applied 

 to plant-structure. 



The Deep-Sea Bottom. In the " Prelim- 

 inary Notes " of the Challenger Expedition, 

 presented to the Royal Society of London 

 by Prof. Wyville Thomson, are to be found 

 some observations on the Globigerina and 

 on the sedimentary formations at the bot- 

 tom of the sea, which mark a substantial 

 advance in the science of these subjects. 

 The globigerina is a minute foraminifer, the 

 shells of which constitute the great bulk of 

 the chalk formation. An ocean sediment 

 known as the "globigerina-ooze" also con- 

 sists principally of these shells, and hence 

 it is to be regarded as a true chalk for- 

 mation. Hitherto Prof. Wyville Thomson 

 and Dr. Carpenter have supposed that the 

 globigerina is an inhabitant of the sea- 

 depths, while other English, as well as 

 American and German, naturalists have in- 

 sisted that it is a surface animal. In these 

 "Preliminary Notes," Prof. Thomson very 

 frankly admits the erroneousness of his own 

 view. In fact, the living globigerina is, he 

 says, very different in appearance from the 

 dead shells we find at the bottom of the sea. 

 In the living animal the shell is clear and 

 transparent, and each of the pores which 

 penetrate it is surrounded by a raised crest, 

 the crest round adjacent pores coalescing 

 with a roughly-hexagonal net-work, so that 

 the pores appear to be at the bottom of an 

 hexagonal pit. At each angle of this hexa- 

 gon the crest gives off a delicate, flexible, 

 calcareous spine, sometimes four or five 

 times the diameter of the shell in length. 

 These spines radiate symmetrically from 

 the direction of the centre of each chamber 

 of the shell, and the sheaves of long, trans- 

 parent needles crossing each other in differ- 

 ent directions have a very beautiful effect. 

 The nature of the deposit at the bottom 



