30 1< NOTES AND MEMORANDA. 



In Other cases embryonal areas of the same nature were 

 formed, which went through similar processes of segmentation ; 

 although the units produced, instead of developing into 

 Monads, were seen to become transformed into brown vesi- 

 cular bodies, which subsequently germinated into Fungus- 

 filaments. Whilst affirming that he is now able to deter- 

 mine pretty surely the occurrence of either one of these phe- 

 nomena. Dr. Bastian says : 



" Experience has shown me that, if an infusion has been 

 heated for a time to 212° F., the pellicle which forms on its 

 surface very frequently never gives rise to an embryonal area. 

 If the infusion has been prepared at a temperature of 149° — 

 158° F., the embryonal areas which form will give origin to 

 Fungus-germs ; whilst in a similar infusion prepared at 120° 

 — 130° F., the embryonal areas, which seem at first to be in 

 all respects similar, break up into actively moving Monads." 



Dr. Bastian then proceeds to give an account of the origin 

 of Paramecia, laying stress upon the fact that, in order to 

 obtain such organisms, it is necessary to employ a filtered 

 infusion made with cold water. His observations on tliis 

 subject were, in the main, confirmatory of those of M. Pouchet. 

 Thousands of egg-like bodies, varying in size from -rro" to 

 ■g-|-o" were seen developing throughout the whole substance 

 of a thick pellicle. He says — " It seemed to me that the 

 differentiation took place after a manner essentially similar 

 to that by which an ordinary ' embryonal area' is formed. 

 The small embryos did not appear to represent the earlier 

 stages of large embryos ; and it seemed rather that spherical 

 masses of the pellicle of different sizes began to undergo 

 molecular changes, which terminated in the production of 

 Paramecia of a correspondingly different bulk. Just as in 

 the previously described embyonal areas masses of different 

 sizes began to exhibit signs of change, so also here spherical 

 portions of the pellicle, differing within the limits above men- 

 tioned, began to undergo other heterogenetic changes. This 

 was first indicated by an increased refractiveness of the area 

 (especially when seen a little beyond tbe focal distance) ; and 

 almost simultaneously a condensation of its outer layer seemed 

 to take place, whereby the outline became sharply and evenly 

 defined. At this stage an actual membrane is scarcely appre- 

 ciable, and the substance of the embryo (when examined at 

 the right focal distance) scarcely differs in appearance from 

 the granular pellicle of which it had previously formed part. 

 So far as it could be ascertained, the individual embryos did 

 not increase in size, although they went through the follow- 

 ing series of developmental changes. The contained matter 



