8 



HARD WI CKE ' S S CIE NCE-GO SSI P. 



senting such unusual and interesting phenomena. 

 Such exceptional development does at first appear 

 to place the organisms exhibiting it outside the 

 vegetable boundary line, but a little reflection is 

 sufficient to show that the difference is only one of 

 degree. Every vegetable cell, animal also, originates 

 as a naked speck of protoplasm ; in phanerogams a 

 cellulose coat is developed so early that the amoeba 

 is imprisoned at once in a comparatively rigid shell 

 which prevents all individual motion. That this 

 early imprisonment of the protoplasm is the only 

 reason for the absence of movement is proved by 

 the fact that in certain instances similar movements 

 have been observed in flowering plants, as by Brown 

 in the " corpuscula " of the Cycadese, and more 

 recently by Mr. F. Darwin, who has observed the 

 emission of pseudopodia from glandular hairs near 

 the base of the leaf of the teasel. In the vascular 





Fig. 8. — Germinating spores of .y/Kw/ar/a fl/iJa ; a, i, Resting- 

 spores. 



cryptogams, motile protoplasm under the form of 

 antherozoids is common, whereas, in the thallophytes, 

 cells devoid of a cell-wall during some stage of their 

 existence, are yet more frequent. There are two 

 types of naked cells met with in the vegetable king- 

 dom, those concerned with reproduction, known as 

 antherozoids, swarm spores, etc., they never envelope 

 solid food, and locomotion is effected by means of 

 cilia or flagelliform appendages ; the second and less 

 common is the amceboid form, which always belongs 

 to the vegetative system, and moves by means of 

 temporary pseudopodia. The best authorities are by 

 no means agreed as to the specific individuality of 

 the protoplasmic bodies classed with the rhizopoda 

 and known as amcebje ; indeed, the bulk of evidence 

 seems to favour the view that they are transitory 

 stages in the development of higher organisms, 

 although at present all the kinds have not been 



correlated with the perfect and ultimate form. 

 Taking this view, we may regard an amoeba not as 

 an entity but as the universal starting-point of all 

 organisms, the identification of which, as a species, 

 can only be proved by its subsequent life-history, and 

 the most highly-specialised animal or plant is in 

 reality composed of a collection of imprisoned amoebae 

 in various stages of differentiation to serve special 

 purposes. In most orders of fungi, the mycelium 

 permeates the matrix for the purpose of absorbing 

 food and its comparative or total absence in the 

 present order accounts for the prolonged amoeboid 



Fig. g. — Amoeboid cells with crystals and capillitium ; -^a, T,b, 

 3C, The same cell at intervals of five minutes, showing 

 change of shape ; 4a, ifi, 4c, The same cell at intervals of 

 half-an-hour, just before breaking up into spores. 



stage, the plasmodium being nothing less than the 

 vegetative part of the plant, no food being absorbed 

 or assimilation taking place after the formation of 

 sporangia. 



During the autumn of 1879 a quantity of spores of 

 Spiimaria alba (Bull.), taken from a perfectly fresh 

 specimen, were placed along with damp moss in a 

 small porous vessel, which was sunk in wet sand 

 under a bell jar. On the third day some of the 

 spores had commenced to germinate, and at the 

 expiration of a week all had given origin to branched 

 threads, as shown in fig. 8. The threads, which 



