286 



Milk Testing. 



[June, 



give. It should be borne in mind that the change is very considerable from 

 the wide outlook and open air life on the farm to the steady application of 

 hours of lectures and study. Here the rough but systematised notes of the 

 farming days can be developed into an encyclopagdic source of knowledge 

 which will be of lifelong value. 



Some readers of Mr. Pawson's book will realise from their own experience 

 that had they been armed with such information when first they took to 

 agriculture much time might have been saved and energy directed into more 

 fruitful channels. If such be the case, the agricultural student of to-day has 

 sui-ely a big pull over his predecessors. 



Milk Testing— (C. W. Walker-Tisdale. London : J. North, 3s. 6d. net.) 

 This handbook is prepared specially for practical people to whom quick and 

 reasonably accurate tests are of the greatest importance. It is a concise and 

 practical handbook on milk testing, and contains a number of illustrations and 

 test tables. 



An Introduction to Bacterial Diseases of Plants.— (Erwin F. 

 Smith, in charge of the Laboratory of Plant Pathology at Washington : 

 W. B. Saunders, New York. 50s. net.) Most of the knowledge we have of 

 the bacterial diseases of plants has come to us within the last generation. 

 This subject has received much more attention in America than elsewhere. 

 The bacterial origin of Fire-blight of Pear was the first to be discovered by 

 Professor Burrill, of the University of Illinois, about 40 years ago. Since 

 then progress has been slow, and at first doubt as to bacteria being the causal 

 organisms of disease was widely felt. 



The greater part of the work carried out in connection with bacterial 

 diseases of plants has been done by Professor Erwin F. Smith, the author of 

 the present work. It is primarily intended for the use of students working in 

 a laboratory under the guidance of a teacher, but it is full of help and interest 

 for all those who wish to have a more complete knowledge of reseaich 

 methods and experimental work in plant bacteriolog}'. 



The first part of the book gives a general review of bacterial diseases of 

 plants — their geographical distribution, the susceptibility of plants to these 

 diseases, the causes of their spread, and methods for their control. The 

 second part deals with methods of research, and from the simplicity of the 

 apparatus Professor E. F. Smith uses in his own research it is clear that 

 elaborate apparatus is not necessary for experimental work in bacterial 

 diseases of plants. The third part describes certain bacterial diseases well 

 known in America, namely : — Cucurbit Wilt, Black Rot of Crucifers, Stewart's 

 Disease of Maize, Brown Rot of Solanacea?, Bacterial Canker of Tomato, 

 Jones's Soft Rot of Carrot, &c., Bacterial Black Rot of the Potato, Bean 

 Blight, McCulloch's Cauliflower Spot, Angular Leaf Spot of Cotton, Mulberry 

 Blight, Fire-blight of Apple, Pear, Quince, &c., Olive Tubercle, and Crown 

 Gall. Part four contains notes on some additional bacterial diseases, and 

 discusses the question of stimuli — chemical and physical — underlying tumour- 

 formation in bacterial diseases of plants. The author argues that his 

 discoveries in connection with tumour-diseases caused by bacteria, particularly 

 Crown Gall, have a profound relationship to animal cancer ; the solution of 

 this latter problem he believes to be very near. A few pages at the end of 



