Ki';\"ii:\\'s. 



HACTEKlOLOdV. 



Microbes iiiul Toxins. — By Dk. lillKNNli BLKNliT (of ihc 



Pasteur Institute, of Paris), with a preface by lil.lE Met- 



cilNiKoi-T. Translated from the I'-rench by Drs. C. Broquet 



and W. M. Scott. xvi + 316 pages. 7i-in. X5-in. 



(VV. Heinemann. Price, 5/- net.) 



The writing of a booklet on some technical subject which 

 shall be interesting and intelligible to the educated public 

 and also correct and which shall at the same time assume no 

 previous knowledge of this or kindred subjects, is a much 

 more difficult task than might at first sight appear, and few 

 who have the requisite knowledge have the necessary patience 

 to carry it through. 



The writer of the book before us is eminently (jualified for 

 the work he has undertaken, and has succeeded in making 

 every page of it both interesting and easily intelligible. A 

 short summary of its contents precedes each chapter so that 

 it is easy to find any details for which we are seeking. 

 InHammation, imumnity, antitoxins and vaccines and a host of 

 similar subjects are, of course, dealt with. But besides these, 

 reference is made to subjects of more general interest. The 

 bacteria of coal, the root nodules by which certain plants are 

 able to abstract the nitrogen from the air, and the lactic 

 bacteria which ferment milk are all described. It may be 

 news to some of us that our large intestine is " not only a 

 useless but an injurious organ," but the author assures us 

 that this is so and maintains his point well. By far the best 

 general account of the microbes of health and disease that 

 we have yet seen, is contained in the volume before us. 



S. H. 



BIOLOGY. 



The Origin of Life : being an account of experiments u-ith 



certain superheated saline solutions in hermetically 



scaled vessels. — By H. Charlton B.^stian. M.D.. F.R.S. 



76 pages. 10 plates. 10-in. X 6i-in. 



(Watts & Co. Price 3/6 net.) 



It is somewhat difficult to know just what to say about a 

 book like this, in which the fundamental axiom of biology, 

 " omne vivum ex vivo," is boldly challenged — moreover, a 

 book written, not by a dabbler, but by a trained man of 

 science, and a Fellow of the Royal Society to boot — and in 

 which the author sets out in detail the methods and results by 

 which he has proved, to his own satisfaction, at any rate, that 

 under certain conditions, living organisms arise from dead and 

 even inorganic matter by spontaneous generation. 



As the question of spontaneous generation, or abiogenesis, 

 is usually regarded nowadays as a matter of purely historical 

 interest, and as the author of this book has not dealt with the 

 earlier history of the question, it may be worth while to con- 

 sider this. Briefly, the doctrine of spontaneous generation was 

 held by the ancient naturalists from .Vristotle onwards, and 

 after being severely shaken by Kcdi in 1668, was revived by 

 Needham in 1748, still more severely shaken by Spallanzani, 

 Franz Schnltze, and Schwann between 1775 and 1837, revived 

 again by Pouchet in 1859, and finally (as most biologists hold) 

 disposed of altogether by Pasteur and Tyndall between 1860 

 and 1876. 



For at least two thousand years, from Aristotle (325 B.C.) 

 to Redi's time, it was firmly believed that rats and mice were 

 " begot of the mud of Nylus," dew gave rise to insects, worms 

 were generated in cheese and timber, beetles and wasps in 

 dung, and so on ; though from time to time there were those 

 who had their doubts about all this, like Sir Thomas Browne. 

 Until Kedi made his simple and crude experiments, 

 apparently no one h.id attempted to test the truth or otherwise 

 of spontaneous generation. Redi exposed meat in jars, some 



left open, others covered with parchment and others with fine 

 wire gauze. The meat in all the jars became spoiled, of 

 course, and flies, attracted by the smell, laid their eggs in that 

 left uncovered, a crop of maggots arising therefrom ; in the 

 case of the covered vessels the flics laid their eggs on the 

 gauze but no maggots appeared on the meat itself. Redi 

 concluded that all supposed cases of spontaneous generation 

 were due to the introduction of living germs from outside. 

 Huxley remarks of Redi's work, " the extreme simplicity of his 

 experiments, and the clearness of his arguments, gained for 

 his views and for their consequences almost universal 

 acceptance." 



So far as larger organisms were concerned, therefore, Redi 

 may be said to have settled the question of biogenesis versus 

 abiogenesis. Soon after Leeuwenhoek discovered the 

 existence of bacteria, in 1687, spontaneous generation was 

 again invoked — this time in order to account for the origin of 

 microscopic organisms. The first experimental test, 

 apparently, was made by Needham (1748), who extracted 

 meat-juice by boiling, enclosed it in vials which he corked 

 and sealed, then heated the sealed vials and set them aside; 

 in course of time the juice was found to swarm with bacteria, 

 and as Needham believed he had killed all living germs in the 

 juice by repeated heating, he concluded that the organisms 

 had arisen by spontaneous generation. Spallanzani. in 1775, 

 first made use of narrow-necked glass flasks in the experi- 

 mental study of the question, arguing that Xeedham"s methods 

 were careless and insufficient, and that it was better to use 

 vessels which could be hermetically scaled. Spallanzani 

 worked with scrupulous care and precision, placing vegetable 

 infusions and meat juice in his flasks, sealing the necks in a 

 flame, and immersing the flasks in boiling water for about an 

 hour in order to destroy any germs that might be already 

 present. His infusions remained unchanged, and he drew 

 the obvious conclusion that even microscopic organisms are 

 not spontaneously formed in nutrient fluids. Needham 

 objected to these results, maintaining that prolonged boiling 

 would destroy not merely germs but also the " vegetative 

 force " of the infusion itself ; but Spallanzani easily disf)Osed 

 of this objection in his later experiments by showing that 

 when the infusions were again exposed to the air, no matter 

 how severe or prolonged the boiling to which they had been 

 subjected, the organisms appeared. 



Now we come to what, until the appearance of Bastian's 

 books, was generally considered to be the final phase in this 

 controversy. The discovery of oxygen by Priestley in 1774 

 gave rise to doubts as to the conclusive nature of Spallanzani's 

 work — oxygen, it was argued, is necessary for active life, and 

 the boiling of the flasks might have driven out the oxygen. 

 Hence it became necessary to experiment under conditions in 

 which the nutrient fluids are made accessible to the 

 atmosphere. F'ranz Schultze in 1836. and Theodor Schwann 

 in the following year, devised apparatus in which air was 

 drawn through sulphuric acid, or heated strongly, on its way 

 into the nutrient fluid ; both of these experimenters took care 

 to have their flasks and fluids thoroughly sterilised, and their 

 experiments showed that the latter remained uncontaminated. 

 Once again, however, the question was opened up. by the 

 publication in 1859 of Pouchet's experiments: but Pasteur's 

 brilliant researches of 1860 and succeeding years proved that, 

 ingenious though Pouchet's experiments undoubtedly were, 

 they were marred by several sources of error — that is, he had 

 left several loopholes for the entry of germ-laden dust into 

 his fluids. Finally, in 1876 Tyndall made his classical and 

 crucial tests with " optically pure " air. and — at any rate for 

 the majority of biologists — the doctrine of spontaneous 

 generation was ejected from its last stronghold. 



As remarked by Locy (" Biology and its Makers," 1908), 

 the work of Pasteur and Tyndall "showed that under the 

 conditions of the experiments no spontaneous origin of life 

 takes place. But while we must regard the hypothesis of 

 spontaneous generation as thus having been disproved on an 



