234 HETEROGENETIC ORIGIN 



had been adequate to exclude all such Ciliates and any possible 

 germs to which they may have given rise. But if the filter could 

 thus exclude contamination by Chilodons, it ought to be similarly 

 potent in excluding Kolpodas or any bodies (nature unknown) 

 which may act as their germs. 



The individualised portions of the pellicle, of the actual size of 

 the Ciliate matrices ultimately produced (after their enclosure 

 within limiting membranes), represent the first appearance of these 

 bodies in properly filtered vegetal infusions. These primary 

 matrices show themselves, as I have said, mostly in from three 

 to eight days, and subsequently remain stationary in size. This 

 may be termed the direct origin of Ciliates from the pellicle, in 

 contrast to another mode, occurring later, now to be referred to, 

 which can perhaps be best spoken of as the amoeboid origin of 

 Ciliates in the pellicle. 



In this second mode of origin, the matrices, from minute 

 beginnings, progressively increase in size ; and when growth 

 ceases generally become enclosed in thick cysts, often having 

 a brown colour. These are rapidly formed and contrast notably 

 with the often scarcely visible, pellucid cysts of the primary 

 matrices. 



This amoeboid origin of the Ciliate matrices reveals itself also at 

 comparatively late periods — mostly from the tenth on to the twenty- 

 fifth day. They appear partly in the original pellicle, and partly 

 in the numerous zoogloeal, villous-like extensions therefrom into 

 the fluid below, such as are commonly found on the under surface 

 of old pellicles. Some of these extensions crowded with Ciliate 

 matrices are shown in Fig. 51, A (x 15). 



They begin as minute corpuscles, which I have traced down to 

 about 1/5000 inch in diameter, and gradually increase in size up to 

 that of small or medium- sized primary matrices ; though they 

 never, I think, quite equal the very large primary matrices that 

 may often be found taking origin directly from the substance of the 

 pellicle. I call this " an amosboid origin " in the pellicle because 

 these corpuscles, when they become larger than the tiniest specks, 

 are seen to resemble embryo amoebae in a resting stage. Their 

 substance is pellucid with a few small granules scattered through 

 it ; and there is no appearance of their being aggregates of Bacteria 

 such as we have invariably found to be the case with the primary 

 matrices. No nucleus is to be seen in their interior ; and they are 



