1222 Journal of Applied Microscopy 



ditions: (1) 6°-8° C, (2) 12°-18° C. (12°-15° C. in Rana), and 22°-25° C. 

 (20°-24° C. in Amblystoma). Measurements were made of tlie length, of the 

 total weight when freed of superficial water, and of the dry weight, and the results 

 were tabulated. It was found that the dry weight is practically unaffected by 

 temperature, and that, therefore, the acceleration of growth accompanying a rise 

 of temperature is almost entirely due to " the changed rate of imbibition of water." 

 The maximum percentage of water in tadpoles reared in high temperatures is 

 slightly greater than in those which have lived in lower temperatures. The 

 maximum total weight of the animals reared in low temperatures is greater than 

 that of those in higher temperature conditions. Animals kept for seven days in 

 a temperature of 12°-15° and then placed in a warm chamber show a greater 

 rate of increase of imbibition than those which have been in the high tempera- 

 ture from the beginning. r. p. 



Jennings, H. S. Demonstrations of the Reac- In a report of a recent meeting of the 

 N°l iz Un^^^"^^^^^^ Organisms. Science, Zoological Journal Club of the Univer- 

 sity of Michigan, the author gives an 

 account of a series of demonstrations by means of the projection apparatus, of 

 some of the more striking facts in the reactions of the unicellular organisms. 

 Among many matters demonstrated, the most important were : (1) The collec- 

 ting ("positive chemotaxis ") of Paramcecia about a bubble of CO 2 and in min- 

 eral acids. (2) The spontaneous collections of the organisms, due to CO 2 

 excreted by themselves. (3) Negative chemotaxis to salt solutions. (4) The 

 absence of orientation in chemotaxis. (5) The " motor reaction " of Oxytricha. 

 (6) The essential identity of "positive chemotaxis " and "negative chemotaxis." 

 In view of certain recent criticisms of the author's brilliant and fundamentally 

 important results, this record of demojistratioiis of the facts in the case is espe- 

 cially welcome. r. p. 



CURRENT BACTERIOLOGICAL LITERATURE. 



H. W. Conn. 



Separates of papers and books on bacteriology should be sent for review to 

 H. W. Conn, Wesleyan University, Middletown, Conn. 



Eckles. An Abnormal Fermentation of Bread. Several instances of a slimy fermenta- 

 Pmceedings of the Iowa Acad, of Sc. 7: ^^^^ ^f ^read appearing a day or two 



Juckenack, A. Beitragzur Kenntnis desfaden- after the baking have been recorded 

 ziehenden Brotes. Zeit. f. Analyt. Chemie. ^^^ studied in recent years. Eckles 

 Pp. 73-01, 1900. -' 



has found the trouble quite common in 



a number of localities. The sliminess appears only in bread that is kept warm 



for some hours after baking, and makes its appearance on the third or fourth 



day. The bread is disagreeable in odor, becoming quite musty and stale, and 



extremely slimy. Eckles finds a number of bacteria present in such bread, but 



concludes that the trouble is due to two species : B. mesentericus vulgatus and 



B. liodermos, both of which organisms are found capable of producing such a 



