NOTICES OF BOOKS. 87 



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Beitrdge zur Biologie der PJlanzen, herausgegeben von Dr. Ferdinand 

 CoHN. Drittes Heft. (Contributions to Vegetable Biology, 

 edited by Dr. F. Cohn.) 



The third part, completing the first volume, of this work, which is 

 entirely ^devoted to vegetable biology, contains an interesting 

 series of articles by various contributors. The first is by 

 Dr. Schroeter, on the development of some of the Rust Fungi. The 

 cycle of the alternation of generations, or different stages in the de- 

 velopment, of Piiccinia graminis are very well known, although no 

 sexual organs have been observed. Dr. Schroeter's investigations 

 refer to the common Uredo found on Carex hirta, which he regards as 

 Puccinia Caricis, DC. A number of careful experiments have led him 

 to the belief that he has discovered in (Ecidium Urticce, Schum., a 

 fruiting form of Puccinia Caricis. A second set of observations relate 

 to a common form of Uromyces found on a variety of Grasses. The 

 JJredo of this Fungus has been described as Epitea Pace, Tul., and E. 

 BactyUdis, Otth. ; its teleutospores as Uromyces Dactylidis, Otth., 

 Capitularia graminis, Niessl., Uromyces graminum, Cooke, and Puc- 

 cinella graminis, Fckl. Dr. Schroeter designates this Fungus (in all 

 its states) as Uromyces Bactylidis, not having been able to detect any 

 differences between that growing on Poa and that on Bactylis and 

 other Grasses, either in the Epitea or in the Uromyces. He thinks there 

 is no doubt from his own observations that CEcidium Ranunculacearum, 

 at least as it appears on Ranunculus bulbosus and R. repens, belongs 

 to the cycle of the different stages of development of Uromyces 

 Bactylidis. Further, perhaps the forms found on R. aoris, polyan- 

 themos, auricomus, and lanuginosus should also be referred here. — Dr. 

 Just contributes the results of some investigations on the resistance to 

 evaporation offered by the epidermal tissues. Pared and unpared 

 Apples were used in the experiments. Without describing his mode 

 of procedure, the results may be briefly stated as follows, temperature 

 being the only agent taken into consideration. At relatively low tem- 

 peratures the evaporation from the unpared Apples was very slight. 

 Thus at 21° C. it only amounted to 3-322 grammes in ninety-six hours, 

 against 44*24 grammes per square decimeter during the same period 

 from the pared Apples. At a very high temperature, 97° C, the 

 evaporation from the pared and unpared Apples was within a quarter 

 of a gramme of being equal for the ninety-six hours ; the unpared 

 giving off 73*89 and the pared 73*67 grammes per square decimeter. The 

 greatest amount of evaporation from the pared surface was 46° C, at 

 which temperature it reached 85*86 grammes per square decimeter. 

 Above and below this point there was an almost uniform decrease in 

 evaporation. The greatest amount of evaporation from the unpared 

 sarface was 78*11 grammes per square decimeter at 83° C. The dura- 

 tion of all the experiments, and there were eleven pairs, was the same, 

 and the weights were taken every twenty-four hours.— The third 

 paper is by Dr. Schroeter, and is entitled " A test of some disinfect- 



