226 



suggest to those of us who do beheve in it any substitute for 

 such work which can be guaranteed to go as far in developing 

 rigorous habits of thought ? 

 Cambridge, Massachusetts. 



Starch grains are made the subject of a recent paper by Pro- 

 fessor Henry Kraemer, of Philadelphia. Among the statements 

 of interest to high school pupils are the following : The starch 

 grain consists of two nearly related substances, the one a colloid, 

 which takes up aniline stains, and the other a crystalloid, which 

 becomes blue with iodine. The starch grain is made up of con- 

 centric layers, one series of which contains a large proportion of 

 crystalloids, while the other alternate layers are composed mostly 

 of colloids. While heating the starch grains in water rapidly 

 changes the structure of the grain, it is only upon the addition of 

 chemicals or ferments that denaturization is brought about. 



Dr. John W. Harshberger has recently found a slime mould 

 which had left its saprophytic habit, assuming a grass-killing one. 

 The slime mould, PJiysanim cinereuni Pers., formed over night 

 "patches of blackened grass," and in "a few days these black 

 patches, if disturbed with the foot or a stick, gave off little clouds 

 of dark brown spores. The original patches were small and few 

 in number, from 6 to 12 inches in diameter and of irregular shape. 

 The rains and damp weather of early August, 1905, aggravated 

 the injury to the lawn, for the patches spread over much larger 

 areas and covered portions of lawn 25 feet in diameter, of irregular 

 outline, with smaller patches scattered in the circumscribed space." 

 The disease affected only the leaves, for the above-mentioned 

 patches afterward regained their fresh, green color. 



The May Bulletin of the Torrey Botanical Club, contains an 

 article by Harry P. Brown on algal periodicity in certain ponds 

 and streams in Indiana which were studied throughout the year. 

 Among the conclusions reached the following are of general 

 interest : 



