1032 EXPERIMENT STATION RECORD. 



bus been noticed by many investigators, and tLe presence of tliis slime is con- 

 sidered a normal function of the organism. 



The author has studied a number of races of this organism from plants of 

 various kinds. lie has found that slime is formed by a majority of the races 

 upon solid media, and that, as a rule, for its formatio'.i the presence of sugar 

 and a source of nitrogen are required. Some races of organisms were found to 

 produce slime, while others did not. The most suitable sources of nitrogen 

 were asparagin and nitrates, and, as a rule, an optimum temperature or 22"^ C. 

 is to be preferred, although with a race obtained from the black locust the 

 optimum was 26° C. 



The experiments on the physiological activities of the various races of the 

 micro-organism showed that after their isolation from the root nodules they all 

 differed. With regard to the function of the micro-organism in the nodule 

 thex'e is said to be strong evidence that it is to produce slime which may be 

 closely related to the carbohydrates of the nucleoproteid molecule. The slime 

 in all likelihood is partially utilized in the formation of the nodules. There is 

 in this respect a true symbiosis so far as the nodules are concerned. The slime 

 may also be transported to other parts of the plant where it is utilized, but 

 there is no evidence to show that the albuminoids of the micro-organisms are 

 utilized by the growing plant, as the majority of them still retain their chro- 

 matin. The formation of slime was found proportional to the nitrogen supplied, 

 and there appeared to be no fixation of nitrogen in pure cultures. 



The inconsistencj' of the results hitherto obtained in the inoculation of legu- 

 minous crops with bacterial cultures is believed by the author to be due partly 

 at least to the fact that the slime-forming function of the micro-organism had 

 not been recognized and races incapable of slime formation had been used. 



The structure of RMzobiuni leguminosarum, R. G. Smith {Proc. Linn. Soc. 

 N. 8. Wales, 31 {1901), pt. 2, pp. 295-302, pis. 2). — In a previous publication 

 (E. S. R., 12, p. 314) the author concluded fi'om his studies of R. leg an tin os arum 

 that it was a form of yeast, but subsequent studies have led him to the con- 

 clusion that it is a compound micro-organism and consists of cocci, micrococci, 

 or diplococci, the chromatin of which may be swollen or condensed within a 

 tubular, straight, or branching rod or capsule. Since the Rhizobium cell is a 

 tubular capsule containing spherules it is easy to understand that by an 

 increase in the number of these spherules the cell may become misshapen, and 

 irregular forms, such as T, Y, and other shapes, be produced. 



The distribution of prussic acid in the vegetable kingdom, M. GRESHorr 

 (Rpt. Brit. Assoc. Adv. *S'c/.. 1906. pp. iJ8-i-'/.'/). — In a paper presented before 

 this association, an abstract of which has already been noted (E. S. R., 18, 

 p. 729), a list is given of species of plants in which hydrocyanic acid is known 

 to occur, and the synthesis and function of hydrocyanic acid are discussed. 



The author recognizes 2 forms under which hydrocyanic acid occurs in plants, 

 one in combination with acetone and the other with benzaldehyde. In the 

 Rosacene and many other plants the hydrocyanic acid is said to occur in the 

 latter form, and by many physiologists it is believed to have nothing to do with 

 the breaking down or biiilding up of proteids, but that this sul)stance is formed 

 by the plant from sugar and nitrates for its defense. On the other hand, those 

 who have studied the occurrence of hydrocyanic acid in Pangium ednle and 

 other tropical plants are inclined to agree with Treub that it is a stage in the 

 normal formation of proteids in jilnnts. 



The chemical aspects of cyanogenesis in plants, "W. Dunstan and T. A. 

 Henry (Rpt. Brit. Assoc. Adv. ScL, 1906, pp. lJf5-157). — It is said that while 

 in all plants in which cyanogenesis has been investigated some free hydro- 

 cyanic acid may exist, there is always present a cyanogenetic glucosid which is 



