H 



beyond a certain time. Periodicity is unknown in lifeless matter, 

 any kind of which may, iinder certain conditions, be preserved 

 for ages. 



3. It has the power of reprodticing its like, certainly in two 

 ways, probably in more than two. 



4. It can digest and assimilate food unlike its own sub- 

 stance. Such processes as solution, chemical decomposition, and 

 crystallisation, afford us no parallel with assimilation. 



5. It is capable of feeling hungry. When the tiny speck of 

 living jelly comes into contact with a particle of food, the animal 

 proceeds to enclose the morsel by flowing round it. In its starved 

 condition the creature spreads its root-foot in every direction, until 

 at last it touches something it can feed upon. 



6. Perhaps as a sixth characteristic of the monera, we may 

 admit a tendency to assume a conditio7i of rest. What that is, in the 

 cycle of the creature's history, which inclines it to give up feeding 

 and motion, and to repose for a while before breaking iip into a 

 swarm of progeny, it is hard to say. It may be induced by 

 changes in the temperature of the medium in which it lives, but 

 this does not seem altogether probable. Perhaps this desire to rest 

 may be admissible as the manifestation of a low form of instinct. 



We now come to a creature, the Amceba, which is higher in 

 organization than the Moneron. The Amoeba, — 



7. Possesses a Nucleus. — In the ascending scale of life, it 

 is the first example of a complete cell with nucleus. 



8. Besides the nucleus, and quite unlike it, the microscope 

 detects within the body of the animal, a clear space which is 

 known as the vesicle or pidsating body. This may be observed 

 alternately to contract and expand. The pulsation is rhythmical 

 as in the heart of a mammal. 



The next creature in order of complexity is the Arcella. 

 It is essentially an Amoeba, but it is able, — 



9. To encase its body, doubtless for protection, with hard 

 particles, such as grains of sand. Tlius it forcibly reminds us of 

 the tubes, coated with small shells, inhabited by the larva of the 

 Caddis-fly. Surely this selection of suitable materials for the 

 purpose of constructing a covering, is worthy of the name of 

 instinct. 



