REFERENCES AND QUOTATIONS. 327 



scientific dress, dualism is here complete ; whereas, Physics and 

 Chemistry make their laws, applying to inorganic as well as to 

 organic nature, comprehensible in their form, purport, and effects. 

 KoUiker knows nothing of the constitution of his laws. The doctrine 

 of natural selection allows us to recognize the causes and effects of 

 heredity and adaptation, and establishes the phenomenal series un- 

 der the form of laws. But laws which are founded only on a plan 

 which is to be carried out prospectively and in subservience to this 

 dower of imperfect organisms, are ignored by natural science. 



" Ueberdie Herkunft unserer Thierwelt. Einezoo geographische 

 Skizze von L. Riitimeyer (Basel, 1867). We have made* copious 

 use in our text of this extremely instructive writing. 



" A. R. Wallace, Malay Archipelago. P. 10, &c. See also his 

 remarkable and comprehensive work on the Geographical Distri- 

 bution of Animals. 



" G. Koch, Die indo-australische Lepidopteren-Fauna in ihren 

 Zusamnenhang mit den drei Hauptfaunen der Erde. (i Ed., Ber- 

 lin, 1873.) 



'" Peschl, Neue Problepne der vergleichende Erdkunde, 1870. 



'" Unless we connect the Dinotherium with Mastodon and Ele- 

 phas. Between the pliocene Mastodon Borsoni and the Elephas 

 primigenius, twenty species are interposed, among which are our 

 still living species, the Indian and African elephants. The limits of 

 the two genera are hereby entirely obliterated. According to other 

 statements, the Elephas primigenius (the mammoth) falls into at 

 least four geographical varieties, which join on to the American 

 species. A dwarf species ot elephant is found in the caves of 

 Malta, which in dentition attaches itself to the African species. 



'* Joh. Schmidt, The Relationships of the Indo-Germanic Lan- 

 guages. 1872. 



" Various antagonists of the doctrine of descent have vented 

 their moral dismay in the most poignant expressions, precluding 

 any scientific discussion, on finding that the pedigree of the Verte- 

 brata, and therewith of man, is actually traced beyond the verte- 

 brated animals to so low a being as the Ascidians. It is otherwise 

 with the critics of Kowalewsky's and KupfFer's observations, who 

 acknowledge the facts, but think themselves obliged to differ in 



