AGEICULTURAL BOTANY. 27 



Tho author claims that this hypothesis is open to mtieism, both on morpho- 

 lojiical and physiological grounds. 



The lens cells are present in many cases on leaves and other organs where 

 there is no question of their functioning in light perception. In experiments in 

 \A'hich the elimination of the lens function has been effected the results have 

 been so contradictory that no definite conclusions can be based on them. In 

 some special cases the lens cells did appear to bring about a concentration of 

 the light on the chlorophyll grains, and this would seem to indicate that they are 

 effective in promoting a greater illumination of the chlorophyll grains. With 

 the possible exception of these few cases, the author concludes there is no satis- 

 factory evidence to show that the lens-shaped cells can be regarded as special 

 adaptations, either for light perception or for the more efficient illumination of 

 the chlorophyll grains. 



The photodynamic effect of extracts from etiolated plants, W. Hausmann 

 and L. von Portheim (Biochcm. Zt-schr., 21 (UJOD), No. 1-2, pp. 5/-5S).— Ex- 

 periments were made with methyl-alcoholic extracts of etiolated seedlings of 

 wheat, oats, maize, barley, peas, and beans, and the extracts were found to have 

 a photodynamic effect even though the solutions were only slightly tinged with 

 yellow. The extracts were found to produce hemolysis of blood corpuscles in an 

 hour or less, dependent upon the source from which they were obtained, when 

 placed in the light, but they were without effect when kept in the darkness. 

 Attention is directed to the fluorescent effect possessed by the extracts. 



The influence of some nutrient solutions on the germination and develop- 

 ment of fungi, O. LuTz (.l///(. MiicoL. 7 iVJO'.)), Xo. 2, pp. .0/-/ J,?). —Experi- 

 ments are reported in which various fungi were sown in culture media in which 

 fungi had been previously grown. One lot of the media was sterilized, the other 

 not, and the fungi used in the experiments were Aspergillus niger, Botrytis 

 cincrca, Cladosporium herbarum, Fusarium solani, Mucor mucedo, Penicillium 

 glaucum, and Rhizopus nigricans. The effect of the media on germination and 

 development was noted. 



In some instances the growth was retarded and in others accelerated, the ex- 

 act reason for this behavior and the chemical nature of the materials left by the 

 growth of the fungi being undetermined. The action is apparently euzymic, the 

 substances secreted by the fungi readily passing through a filter. They are 

 destroyed or greatly modified by high temperatures, and an exposure of 20 

 minutes to direct light or to the violet rays of the spectrum destroyed them. 

 F. solani and A. niger sown in the medium which had formerly grown these 

 organisms wei-e stimulated in their vegetative growth. The metabolic products 

 given off by the fungi enumerated above were found to stimulate or retard not 

 only the same species grown in the medium, but other fungi as well. 



The effect of heat on diastatic ferments, J. Apsit and E. Gain (Compt. Rend. 

 8oc. Biol [Paris], 61 (1U09), No. 28. pp. S67-369) .—The effect of heat on the 

 diastase of wheat was investigated, grains being subjected to boiling water for 

 25 minutes and to the action of dry heat at 160° for 20 minutes. In both cases 

 the vitality of the seed was destroyed, but the diastatic functions were retained. 



It appears that the diastases resist the action of heat to a greater extent than 

 the germinative faculty. In the wheat grains the vitality of which had been 

 destroyed by heat there was still sufficient amylase present to bring about the 

 saccharification of starch. 



The relation between the rennet and proteolytic ferments of plants and 

 their function, C. Gerber {Compt. Rend. Hoc. Biol. [Paris], 67 {1909), No. 28, 

 pp. 332-334). — From a study of the active principle found in the papaya the 

 author is led to believe that there is a close relationship between vegetable 

 rennets and proteolytic enzyms of plants. Their wide distribution and action 

 leads him to suppose that they have a diastatic action assisting in the synthesis, 



