BARD WICKE'S SCIENCE- GOSSIP. 



S3 



festation of the changes in the protoplasm or of the 

 movements that are seen to take place within the 

 organism. In some Amceba this organ appears to be 

 absent. 



The nucleus is not always easily seen in the Amceba, 

 in some specimens none is discoverable, but when 

 present it is seen to differ but slightly if at all in the 

 refractive power of the general protoplasmic sub- 

 stance. It is provided with a delicate membrane 

 and internally is composed of a network, called 

 intranuclear and somewhat similar to that of the 

 general protoplasm. The nucleus (with few exceptions) 

 is present in every cell, and plays an important part 

 in the process of reproduction. It divides previously 

 to the cell in simple asexual reproduction, and in the 

 sexual method fusion of the two nuclei takes place. 



This short account of the morphology of the 

 Amceba leads us to consider, briefly, what is known 

 of the physiology of this interesting organism. 



The problem of how to introduce into its interior 

 the food on which it subsists is answered by the 

 Amceba readily and simply. At any part of its 

 surface the food may enter ; the protoplasm flows 

 round it, slowly engulfs it, and thus produces a food 

 vacuole directly in contact with the protoplasmic 

 substance. The digestion apparently without the aid 

 of gastric juice, without, as far as we know, any 

 special ferment for converting insoluble into soluble 

 substances, is hard to understand. And we reach a 

 very difficult problem in physiology when we try to 

 solve how the matter is absorbed and converted into 

 living material. In our own bodies the gastric juice 

 and other ferment-containing substances are required 

 to bring food directly in contact with the protoplasm 

 of the cells of which we are built up ; but here we 

 have food directly in contact with endosavc, dead 

 protoplasm in contact with living ; and yet, though we 

 have reached the most primitive form of assimilation 

 in the animal kingdom, we are at a loss.to explain how 

 it takes place. I have previously mentioned the con- 

 tractile space and its supposed function, and the 

 movements of protoplasm visible in the endosarc as 

 well as the formation of pseudopodia by which 

 locomotion is effected. 



■\Ye mnst consider the whole substance of the 

 Amceba capable of performing the various functions 

 of life ; and this teaches us an important lesson, that 

 in spite of the absence of differentiation, nevertheless 

 the cell is enabled to perform its various functions, 

 and this we shall see later is not the case among the 

 Infusoria. 



The eminently contractile nature of the protoplasm 

 and its response to electrical, thermal and mechanical 

 stimuli give us, perhaps, the first indication of a 

 nervous and muscular system. The apparently pur- 

 poseful movements of the Amceba, and still more of 

 the higher Infusoria, their behaviour when they meet 

 an obstacle or food, makes us almost fancy that they 

 have at least the sense of touch and the will to act 



on that sensation. This may only be, however, the re- 

 action of the protoplasm to a stimulus, non-intelligent, 

 the result of a law due to the complex nature of the 

 substance. Protoplasm is so complex, indeed, that 

 in spite of the great advance of chemistry within 

 recent years, we are unable to form an estimate 

 of its composition. We know that the chief elements 

 that compose it are carbon, hydrogen, nitrogen, 

 oxygen, and a little sulphur and phosphorus, besides 

 traces of other substances, and we have to remain 

 satisfied with that. How these are built up, it is 

 impossible to ascertain accurately, perhaps because 

 of their complex arrangement into several groups and 

 sub-groups loosely connected, and certainly because of 

 the great practical difficulty of examining chemically 

 a living material. 



This protoplasm is constantly being broken down 

 and as constantly renewed. It resembles the cloud 

 which clings to the mountain-top, remaining the same 

 in form, but the individual particles that compose it 

 ever changing. 



The study of the protean animalcule is the study of 



protoplasm ; and now with this introduction we will 



turn our attention to some members of the large class 



Infusoria. 



( To be continued.) 



HUMOURS OF FOSSIL-HUNTING. 



MANY of my readers, geological and otherwise, 

 have doubtless in the course of their ex- 

 perience been frequently diverted by ideas, both 

 curious and amusing, prevalent in regard to their 

 particular fields of research, among those with whom 

 they have come into contact as they sought for fossils, 

 plants, or other objects of natural history ; but this is 

 more particularly the case, I believe, with those who 

 like myself have " woo'd the gentle fossil from his 

 native rock." May I offer a selection of such as have 

 come under my own notice, in the hope that the 

 perusal may call up a smile to faces that are so 

 generally weighted by nature's many-sided problems. 



It seems hardly possible that in these enlightened 

 days the existence of the fossils in the rocks should 

 remain a mystery, yet in many benighted districts, 

 where I am compelled to suppose the foot of the 

 geologist has seldom trod, people may still be found 

 to whom the riddle is quite insoluble, and who 

 remain provokingly sceptical in spite of explanations, 

 which very often they themselves have called for. 

 Such an one it was who enquired of me if my 

 specimens were not more likely the result of the 

 Deluge, some of the "wicked fishes" in fact, that 

 perished by that catastrophe. 



A complete list of the names applied to fossils by 

 the workmen in pits and quarries would form of itself 

 an article of very considerable length : those given 

 below are a few culled from the many. The heart- 

 shaped Micraster is a "toad," a "snake's-heart," 



