Notes on A Difficulty in Evolution, read at a Meeting 
of the Cotteswold Club, March 20th, 1888. By 
J. Drew, M.B., Lond., F.G.8., &e. 
In drawing the attention of the Society to the subject of 
Evolution, and stating an objection to the whole theory, which, 
according to my reading, has never been advanced before; I 
hope the members will agree with me the difficulty should be 
fairly met, and either the force of it fully allowed, or entirely 
disproved by the logic of facts; for the argument is based on 
the conditions of the blood in the various classes of animals, 
and the apparent impossibility of evolution through the earliest 
mammalian remains found in the secondary rocks. 
The blood of animals is found to be of various colours, red 
in the higher, and white in the lower animals; it may be dark 
brown as in beetles; or yellow as in silk worms; but whatever 
the hue, it always consists of corpuscles floating in a liquor 
sanguinis, and constitutes that pabulum on which the new 
being must live, and develop that body, which is to fit it for the 
circle of its life, for “anima carnis in sanguine est.” 
Probably in all animals, as in man, the first blood cells 
formed are somewhat different to those which circulate in more 
advanced life ; but after a given time the corpuscles peculiar to 
each individual are perfected, and then do not undergo any 
further change during the healthy condition of the animal; 
and possibly the nature of this first formed blood may assist in 
fixing the class of the developing being. 
Blood cells are either round, or oval in shape, and vary 
greatly in size in the different classes of animals; in all mam- 
mals except the camel tribe they are circular disks, but in this 
tribe, and in all birds, reptiles, and fishes they are more or less 
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