terris) and the mud of the Nile continued to produce monsters. 
Since that time the notion of spontaneous generation has r 
ceded gradually from view ; having been driven from 
hiding-place to another, by means of scientific and microscopic^ 
research* until in the present day it has been br° g 
nearly to the vanishing point as possible, throu^ ; t © a , cm 
of Pasteur and others. Those who still cling with pertinacity 
to this opinion wilt not deny that even if all they contend for 
(fruitlessly as I believe) were established as facts, these tacts 
could not interfere with the general proposition above advanced. 
40. In the next place it is obvious that since the commen - 
mentof the recorded history of animal life, as it has left its 
record in the ages of the past, the mould (or type ) m utoch 
creatures are formed has never been replaced. Very many, 
certainly not less than 40,000, species of more or - noble mid 
distinguished plants and animals have disappeared altogether 
from the earth, having been either exterminated by the hands 
of man, or having in other ways perished; whilst we can o 
point to a single new species as having been introduced, eithe 
in the course of nature, or as created by the ha “ d * of “ a ' 
“The whole lapse of geological time has as yet yielded not a 
single new ordinal type of vegetable structure. * 
41 This is strikingly contrasted with facts with wh 
chemical science has made us famihar. Numberless iiew bodies 
have rewarded the pains of the experimentalist, who has been 
able, under the guidance of the atomic theory, to foresee the 
possibility of the existence of such and such a substance, an 
to take the needful steps so to alter or modify the atomic 
structure as to produce the result desired. In many cases we 
may assert that these products of human skill have never before 
existed ; and yet they have their distinctive properties as fixed 
and unalterable as the law of gravitation itsel . 
42 For instance the chemist may take sulphur from the 
volcano, and oxygen from the air; he may separate iodine from 
the seaweed, and vegetable alkaloid, the product of processes of 
growth in certain plants growing at immense altitudes above 
the sea-level. He unites these for the first time ; and produces 
new substances, having most definite forms of crystallization, 
by which the Herapathite, + as it has sometimes been called, 
of one alkaloid can be readily distinguished from another. 
* “Persistent Types of Life,” Professor Huxley quoting Hooker’s Essay on 
Flora of Tasmania. See Lay Sermons, p. 203 and p. 216. 
f After my late lamented friend, Dr. Herapath. 
