19 
leading to air sacs in their interior. In conclusion, Mr. Johnson 
alluded to the monad, or unicellular microscopic animal, as the 
type of the first beginning of life in all animals from the lowest to 
the highest. These microscopic atoms, he well observed, are 
calculated to excite the wonder and admiration of those who 
investigate the subject, and sufficiently attest their divine origin. 
The Present asked to what pecularities of motion Mr. John- 
son had alluded as the distinguishing marks of animal and vege- 
table organisms. 
Mr. Jonnson said as far as his observations went, he thought 
that animals moved as if they had some purpose in view, avoiding 
obstacles, and that, on the other hand, vegetable organisms moved 
much slower, and with a trembling motion. 
Dr. Carpenter said: We have heard with considerable satis- 
~ faction the observations made by Mr. Johnson, and much admired 
the excellent drawings with which he has illustrated his paper, but 
I should like to ask a question or two regarding some of his 
remarks in the earlier part of it. I should wish to know upon 
what grounds he concludes that the actions which he has alluded to 
as taking place in the 4meba, and in some other of the lower 
forms of life in the class Protozoa, are respiratory actions. The 
same action it is which nourishes and which propagates the 
creature, if creature it is. I doubt the correctness of the defini- 
tion as being respiration, any more than it is circulation, or 
motion, or actual life. It may be true animal life. It is 
asserted by some eminent physiologists that the difference 
between the animal and vegetable is the production in the one 
ease of carbonic acid by the act of living, and in the other, 
the decomposition of carbonic acid, and the setting oxygen 
free; but this does not hold good in every case, for some 
-_ undoubted plants produce carbonic acid. It is well known also 
- that the important action of movement.is set up quite independ- 
; ently of respiration, for a simple alteration of density, such as 
occurs on different sides of a moist membrane, gives rise to a very 
f= active movement indeed, which is not respiration, and which is not 
_ hife. It is easily shown by placing liquids of different densities on 
_ different sides of a piece of bladder. I do not mean to insinuate 
_ for one moment that Mr. Johnson is not perfectly right in his idea 
_ that everything has proceeded from some germ which has de- 
_ veloped into the object. I quite agree to the idea that a preceding 
_ germ or ovum is necessary for the production of life, but I cannot 
_ agree for one moment with the suggestion, promulgated by some 
scientific men, that life may be produced by a certain combination 
of forces independent of life itself; yet, the theory propounded by 
