262 



SCIENCE- GOSSIP. 



form and dimensions, for there is no absolute 

 sexual difference, join by means of their stomata, 

 and the micronuclei divide several times, the 

 result being the presence of four nuclei at both 

 ends of each organism. An interchange of certain 

 of these then takes place, and fusion of them 

 results in the so-called rejuvenescence. The 

 advantage of this process is, that the species is 

 practically immortal, as is the case in many of 

 these lower organisms. (See fig. 2.) Paramoecium 

 may also reproduce by fission, or dividing into two, 

 and so on ; but the former method is the more 

 frequent. 



We will now study more in detail the " cilia " 

 and their movements. Each cilium is seen by 

 careful focussing to consist of two parts — (1) a 

 basal part, and (2) an apical whip-like prolonga- 

 tion. The greatest range of movement takes place 

 in this latter portion. There occurs a sudden 

 bending in one direction, and then one just as 

 rapid in the opposite direction, so that the cilium 

 is brought back to its initial position. The ex- 

 planation of this movement is based upon certain 

 assumptions. First of all. that side of the cilium 

 towards which the first movement takes place is 

 held to be thinner than the opposite side, and gets 

 gradually attenuated towards the apex. Let us 

 now suppose that some fluid is forced suddenly into 

 this cilium, which is necessarily hollow. It will 

 bend towards that side where there is least resist- 

 ance— i.e. towards the thinner side. If we now 

 replace our fluid by the endosarc of Paramoecium 

 we have practically the same result. Moreover, if 

 the fluid be suddenly withdrawn we have the 

 cilium rapidly straightened, and perhaps springing 

 back in the opposite direction. (See fig. 3.) 



We have seen that Paramoecium feeds, but we 

 have also a process of respiration going on, or 

 rather an internal respiration, oxygen entering 

 in solution through the ectosarc or through the 

 mouth, being used up in oxidising the substance 

 of both ectosarc and endosarc. The result of this 

 is the breaking down of the protoplasm into bodies 

 such as ammonia and carbon dioxide, as final pro- 

 ducts of katabolism, these being got rid of by the 

 agency of the contractile vacuole. 



We have, therefore, in this organism a striking- 

 exponent, on a small scale, of some of the funda- 

 mental life-factors, namely, absorption, respira- 

 tion, excretion, and, last of all, but not least, 

 reproduction. In other words, it presents us with 

 an illustration of what must, to a certain extent, go 

 on in every living cell, whether solitary or forming 

 a portion of some living tissue. Moreover, this 

 organism possesses a certain power of selection, a 

 fact which is of especial importance to the bio- 

 logist, as it explains many difficulties that have 

 arisen with respect to nutrition ; but this selection 

 is of a more or less instinctive variety, as is 

 evidenced by the fact that unsuitable materials are 

 rejected, suitable ones taken in, and this choice 



exhibited in a very marked manner. We see in 

 the vegetable kingdom a power of selection pos- 

 sessed by the root-hairs of plants, but this, 

 although perhaps of the same ultimate origin, is 

 only evidenced in a passive manner. In fact we 

 find in such organisms as Amoeba and Paramoe- 

 eium, indeed most Protozoa, the first signs of that 

 rather vague term " instinct," which we use so 

 frequently in speaking of animals on a higher scale 

 of evolution. 



The differentiation of the body of Paramoeoium 

 into ectosarc and endosarc opens up another ques- 

 tion of great biological interest, for here we get 

 the first indication of that great division into two 

 main layers, " epiblast " and " hypoblast," that we 

 find in higher animals. The former of these layers 

 is that which gives rise to the protective and 

 nervous systems, the latter remaining for the most 

 part absorptive in function. In the earlier stages 

 of development of all animals, and in some 

 Hydrozoa ( Hydra) for the whole of their exist- 

 ence, these layers are to be distinguished, but in 

 these cases are more differentiated than mere 

 ectosarc and endosarc, for we have the layers 

 comprised of a large number of cells, and there is 

 on this account a greater division of labour. 

 Nevertheless, the two cases are comparable in 

 their gross relations'. The ectosarc is certainly 

 protective, and the cilia may act on occasion as 

 tactile organs, the endosarc being chiefly concerned 

 in nutrition. 



We thus see that Paramoecium repeats on a 

 small scale most of those functions which in more 

 highly organised animals are divided between 

 various aggregates of cells, going to form organs. 

 It is only in this sense that we can speak of these 

 other animals as being on a higher scale of evolu- 

 tion, in that they are enabled by means of these 

 cell-aggregates to effect a division of labour. 

 Further, it is this absence of division of labour 

 which in the case of Paramoecium entitles us to 

 speak of it as a lower organism, for in ultimate 

 analysis of function it is as perfect as any other. 



University College, London, W.C. 



ETHNOLOC4Y OF the -Masai. — Mr. Sidney Hinde, 

 the well-known Eesident of the British East 

 African Protectorate, has just written a fascinating 

 work on "The Last of the Masai." When at the 

 height of their prestige, the Masai neither made 

 slaves nor took prisoners on their raiding expedi- 

 tions, nor did they marry or allow their women to 

 marry outside the sept. As they were in no sense 

 traders, they remained an isolated race. One 

 result of this was the survival of customs and 

 superstitions which elsewhere were surrendered 

 under the pressure of civilisation. Their rulers 

 are credited with the power of second sight, which 

 the people say they can evoke at will. They are 

 believed to transmit the gift to their heirs through 

 the agency of a cunningly kept secret. Mr. Hinde 

 refutes the prevailing view that the Masai are of 

 the same stock as the Zulus. — (Ilev.) J. M. Cobbett. 

 Albany Street, London, A 7 ". IT. 



