Februaby 27, 1914] 



SCIENCE 



327 



While on Mt. Constitution, Orcas Island, 

 Washington, about five o'clock in the evening 

 one summer, Mark Said and I were watching 

 the nighthawks in their tortuous flight. Un- 

 expectedly one of the nighthawks made its dip, 

 with the accompanying " woof," but a few 

 feet from Mr. Said. 



According to his description the bird threw 

 its wings far to the front at the end of his 

 downward glide, so that the uppermost quill 

 feathers were pointed exactly in the direction 

 of his glide. Going at such headlong speed, 

 these quill feathers when thrown edgewise to 

 the air vibrated strongly, causing the " woof." 



Prank A. Haetman 

 Seattle, Wash. 



SCIENTIFIC BOOKS 

 Vorlesungen iiber Landwirthschaftliche Bak- 



teriologie. By Dr. F. Lohnis, Professor an 



der Universitat Leipzig. Berlin, Verlag von 



Gebriider Borntraeger, W. 35 Schoneberger 



Ufer 12a. 1913. 



Agricultural bacteriology is gaining promi- 

 nence in scientific and practical circles. The 

 agriculturist realizes more and more that sci- 

 entific investigations are of help to him and 

 the demand on colleges for courses in agricul- 

 tural topics is constantly increasing. How- 

 ever, text-books are still scarce. The series of 

 lectures by Professor Lohnis is the outcome of 

 & course of lectures in connection with a gen- 

 eral course in agricultural bacteriology given 

 by him in the University of Leipzig. 



The ground is covered as thoroughly as mod- 

 ern knowledge permits. No one realizes more 

 fully than the author how much work is needed 

 to complete our really very meager knowledge 

 in many agricultural branches. The reader 

 must be impressed with the fact, frequently 

 stated, that research is necessary and that au- 

 thors do not agree in many instances. 



The book is divided into two parts — a gen- 

 eral part and a special part. The general part 

 consists of fourteen lectures. The first lecture 

 gives a general introduction to the significance 

 «nd the problems of agricultural bacteriology 

 .and includes a historical review and a list of 



some important books beai-ing on the subject. 

 The shape, development and classification of 

 microorganisms is covered in two lectures. 

 The size of bacteria is admirably illustrated 

 by diagrams showing the relation of the bac- 

 terial content of milk, butter and cheese to 

 definite quantities of these substances. Such 

 illustrations render the book exceptionally val- 

 uable, especially to students. Three lectures 

 are devoted to conditions of existence and 

 multiplication of microorganisms and two lec- 

 tures to methods of cultivation and combating 

 microorganisms. 



Under the general head of "Products of 

 Microorganisms " six lectures are united. The 

 production of pigment, light and heat are dis- 

 cussed. The circulation of nitrogen, carbon, 

 hydrogen and oxygen are given with consider- 

 able detail and illustrated in diagrammatic 

 fashion. These complicated subjects are dealt 

 with in masterly fashion, notwithstanding the 

 fact that some facts are still poorly under- 

 stood. Similarly, a lecture is given to the dis- 

 cussion of the decomposition and assimilation 

 by bacteria of phosphorus compounds and the 

 solution of carbonates and silicates. Mention 

 is also made in this lecture of sulphur and 

 iron bacteria. For the sake of completeness 

 one lecture deals with pathogenic functions 

 of microorganisms. It is hardly necessary to 

 state that this extensive subject is treated 

 briefly. However, the chief principles of viru- 

 lence, infection, immunity, vaccination, serum 

 therapy and chemo-therapy are ably dealt with. 



The second " special " part commences with 

 a lecture on the bacteriology of foods for 

 cattle. Here the author forcefully shows the 

 role played by microorganisms in the ripening 

 and decomposing of foods. Many gaps in our 

 knowledge are clearly pointed out. 



Two interesting lectures give the student 

 the most necessary knowledge of the milk 

 question. The attitude of the author in re- 

 gard to this important subject is of special in- 

 terest. There are at present in this fleld the 

 extreme views of those commercially interested 

 and the no less extreme views of some sani- 

 tarians. Professor Lohnis takes an interme- 

 diate position, recognizing the necessity of 



