1880. ] The Critics of Evolution. 319 
backward into the cesophagus, The mouth cavity is then again 
opened and the same process repeated. To prevent the food being 
sucked back from the cesophagus, it is probable that some of the 
numerous fibres in the muscular sack near the origin of the for- 
mer can, by contraction, close its opening, but in any case as the 
trunk presents a free tube, and the cesophagus leads into the 
closed alimentary canal, it is evident that the former offers the 
easiest route for a supply to fill the mouth vacuum. 
In the muscular mouth sack, we have thus a pumping organ, 
of action too simple to be misunderstood. As for the so-called 
“sucking stomach,” its delicate membranous structure is cer- 
tainly not adapted for sucking functions, and it probably serves 
only,as a reservoir. It is usually found to contain nothing else 
than air, but Newport asserts that immediately after feeding food 
is also found in it. 
THE CRITICS OF EVOLUTION. 
BY J. S. LIPPINCOTT. 
PoS is a large class of minds even among those who esteem 
themselves educated, who have no acquaintance with science 
and another, perhaps equally large, who have no idea of what is 
meant by the scientific spirit. These all imagine, perhaps, that the 
world of things or phenomena around them, has ever been pretty 
much as it now appears to the superficial gaze, and that men have 
always known about as much about the earth, its origin, develop- 
ment and productions, as they now know. They appear to 
be unconscious of the fact that a century ago we knew almost 
nothing of the constitution of matter, and were holding the 
same crude and puerile ideas about nature that were held 
by the ancients 3000 years ago. They do not seem to be 
aware that but few conquests, from the domain of the un- 
known had been made in physical astronomy, and that almost 
all our knowledge of the composition of the earth and its 
myriads products, animal, vegetable and mineral, have not yet 
been reached. 
A century ago the simplest phenomena were inexplicable ; no 
