438 THE ZOOLOGIST. 



fatal diseases, and may be the cause of ravaging epidemics." The 

 Sporozoa have even been suspected as a cause of that cruellest of 

 human maladies — cancer, and hence these parasites are indi- 

 vidually and collectively enemies to the human race, to be studied 

 and ever combated by biologists and pathologists ; thus the 

 importance of Prof* Minchin's treatise can scarcely be over- 

 estimated. The Infusoria by Prof. Hickson is the last contribu- 

 tion to the volume. We remember as a boy, in the early sixties, 

 turning over the pages of ' Pritchard's Infusoria,' without much 

 appreciable profit or enlightenment, save the charm and awe 

 which such publications impress on the juvenile mind. These 

 pages impress us with the different information that is now so 

 readily attainable, and inspire an optimism as to the advance of 

 biology by future generations. 



We hear much of evolution in these days ; it has almost 

 become a catch-word, and a text for a ready speaker, but how 

 few have really assimilated the idea, or understood the pro- 

 position ! A student of these volumes can fortunately find much 

 of the evidence on which the evolutionary doctrine rests, and thus 

 obtain a real grasp of the greatest of human conceptions. 



A Manual of Palcsarctic Birds. By H. E. Dresser, F.L.S., 

 F.Z.S., &c. Published by the Author at 3, Hanover 

 Square, W. 

 Dresser's ' Birds of Europe ' is a recognized classic in 

 ornithology, but it is necessarily a costly book, above the means 

 of many ; and, again, its bulky volumes constitute a library book, 

 quite unsuited for the travelling naturalist. We therefore wel- 

 come this Manual, which not only gives us the essence of the 

 larger work, but something more as well ; for Mr. Dresser has 

 now taken under his purview the birds of the whole Palsearctic 

 region, and in defining this region he has allowed himself con- 

 siderable latitude in drawing its southern boundary. Africa has 

 offered no difficulty, for the Sahara is all-sufficient there ; but 

 when we come to Asia authorities disagree. The author of this 

 Manual defines the southern limits of the region as running 

 northward of the Arabian Desert, including the tableland of 

 Persia, the highlands of Baluchistan, the whole of Afghanistan, 



