NEW BOOKS, WITH SHORT NOTICES. 110 



It does not seem to Lave occurred to Dr. Bastian to ask himself 

 whether gold-beater's skin is, or is not, permeable to leucocytes. If 

 he had placed a piece under his microscope, he would have recognized 

 the structure of an animal membrane. A little inquiry would have 

 enabled him to discover that gold-beater's skin is made from the 

 intestine of the ox, and he would have discovered openings in it with 

 even a low power large enough for millions of blood cells to pass into 

 and out of a little bag made of such a material. The experiments of 

 Cohnheim must be well known to Dr. Bastian ; he cannot be ignorant 

 of the fact that white blood corpuscles will pass freely through the 

 walls of a fish's swim-bladder, when it is filled with a saline fluid and 

 buried under the integument of a living animal. This experiment has 

 been verified again and again, and is a favourite one with professors of 

 physiology to show their classes the manner in which leucocytes 

 wander through the living tissues. Does he then seriously ask us to 

 believe in this as evidence of spontaneous generation ? or is the illus- 

 tration merely intended to explain what he thinks occurs in other 

 fluids '? We can only believe it found a place in his writings without 

 a thought as to the nature of gold-beater's skin — on the authority of 

 M. Onimus. We may take it, however, as a fair specimen of the 

 carelessness which characterizes the book before us, and of the manner 

 in which every possible unsifted statement has been brought to bear 

 on the argument in favour of Dr. Bastian's opinions. It will occur 

 to the reader at once that the minute particles observed at first in the 

 fluid were the result of its degeneration, or were, perhaps, minute 

 particles of precipitated fibrine. It will be difficult, however, to con- 

 vince most men that they developed into leucocytes. 



The experiments on the origin of Bacteria are certainly the most 

 important part of the work, and it must probably be held as proven 

 that such particles originate in fluids in sealed tubes, even after the 

 most careful manipulation and exposure to a temperature usually 

 destructive to all life. Perhaps other low organisms originate like 

 Bacteria in such tubes. The argument that these organisms arise de 

 novo reduces itself to a very small compass. Either germs have 

 withstood a temperature of between 212° and 307° Fahr., or such 

 forms have arisen de novo. The author assumes, on, we think, very 

 insufficient evidence, the latter alternative. 



Without prejudice, we do not see why the other alternative is not 

 equally probable, especially when we remember that the cause of 

 death is chemical change in the organism. A form of living matter 

 capable of resisting such temperatures may, for all we know, exist in 

 the germs of the lowest living forms, and if so, the whole argument 

 falls to the ground. 



The second part of the work relates to the development of higher 

 from lower forms of life. The author asserts his belief in the evolu- 

 tion of Tardigrades and Eotifers from highly differentiated plants, as 

 Euglena, Vaucheria, &c. He says at page 540, vol. ii., " I have 

 already in my possession much convincing evidence, derived from 

 personal observation, that some water mites and acari, and also the 

 ciliated embryos of Naides may be produced by a direct transforma- 



