320 botanical gazette. f December, 



at the cost of their contents. When they have multiplied to large num- 

 bers in the root hair they accumulate near the apex of the hair as a tu- 

 bular conglomerate of colonies which surround themselves with a thick 

 membrane. After a time of development this structure grows toward 

 the base of the root hair like a hypha-tube, and from this time on be- 

 haves like a true hyphal fungus. The tube has the thick, refractive mem- 

 brane on the outside, and is densely filled with bacteria inside. It pene- 

 trates to the interior of the rootlet and induces the abnormal develop- 

 ment of certain tissues, resulting in the formation of a tubercle. After 

 the tissues of the tubercle have differentiated part of the tubes are dissolved 

 and the bacteria set free, while part remain. The free bacteria multiply 

 freely and take on a somewhat different form (forked) when they con- 

 stitute the well-known " bacteroids." As to the role of the bacteria in the 

 life of the plant, the author agrees with Hellriegel, that they enable the 

 plant to obtain nitrogen, but whether this is taken in the form of com- 

 pounds or from the free nitrogen of the air, he is not prepared to say. 

 The remaining life history of the bacteria has also been worked out by 

 the author, but we can not go further into details. The summary is a 

 most interesting contribution to this important controversy. 



It is startling to compare a past in which botany was regarded as 

 a subject which might be tacked on anywhere, with its present condition, 

 in which there is scarcely a seat of learning in the three kingdoms which 

 is not turning out serious work. But it would be a mistake to 

 suppose that English modern botany has developed a character of its 

 own in which the indirect influence of Darwin's later work can be not 

 indistinctly traced. Darwin by his researches on insectivorous plants and 

 plant movements from a purely biological point of view, prepared the 

 way for this. Gardiner followed with a masterly demonstration of the 

 physical continuity of protoplasm in plant tissues. Mr. F. Darwin has 

 started what is virtually a new conception of the process of growth. On 

 the whole, English botanists have shown a marked disposition to see in 

 the study of protoplasm the real key to the interpretation of the phe- 

 nomena of plant life. The complete analogy between the processes of se- 

 cretion in animals and vegetables, established by Gardiner, and the essen- 

 tial part played by ferments in vegetable nutrition, illustrated by Green, 

 are examples of the results of this line of inquiry.— Nature. 



