September 8, 1916] 



SCIENCE 



361 



Venereal Infections in Animals: G. A. Roberts. 



Observations, investigations and reports indi- 

 cate very wide-spread venereal infections in this 

 country and abroad among domestic animals, 

 horses, cattle, sheep, swine, etc. Such infections 

 have been known to exist in the human family for 

 a long time. 



Few people have recognized the extent and 

 manifold results of these infections. 



The most extensive investigations and the 

 greatest losses, direct and indirect, in animals have 

 been among dairy cattle and breeding herds. 



The specific organism responsible for the infec- 

 tions in cattle has all but universally been accepted 

 as the Bacillus abortus (Bang) . Many cases of in- 

 fection with the B. abortus are too mild to pro- 

 duce clinical symptoms. The results observed in 

 many such infections, however, are: abortions, in- 

 cluding premature births, still births and births of 

 weaklings; metritis (inflammation of the uterus) ; 

 and sterilities, temporary and permanent. 



Retained ' ' after-birth ' ' is quite common in 

 cattle when expulsion of the fetus occurs during 

 the latter half of pregnancy, owing to the peculiar 

 attachment between the fetal membrane and the 

 uterus at the time. 



Nymphomania is not uncommon in cows and 

 mares. 



The relation of this organism to certain udder 

 diseases and the granular venereal disease of cat- 

 tle, to some forms of calf scours and infant diar- 

 rheal troubles, has not been determined, but is 

 suspicious of a close relationship. 



Resistance and Immunity in Plants: F. A. Wolf. 

 This paper contains a brief summary of the 

 facts which have been correlated with resistance 

 and immunity in plants in attempts to explain the 

 underlying causes. Attention is called to several 

 investigations dealing with morphological differ- 

 ences between susceptible and immune varieties. 

 Consideration is also given to the influence of min- 

 eral nutrients in the soil upon resistance. The dis- 

 cussion also includes those causes which reside 

 within the protoplasm of the host plants such as 

 differences in acidity, tannin content, etc., of sus- 

 ceptible and immune varieties. It is believed that 

 too little attention has heretofore been given to 

 the inherent characters of the parasitic organism 

 which determine the virulence of the parasite. 



Some Methods of Making Lantern Slides: Z. P. 



Metcalp. 



The need of some form of projection in science 

 teaching and the general utility of lantern slides 

 was emphasized. Two methods of making lantern 



slides were discussed and examples of various 

 kinds of lantern slides were shown. 



Trees and Shrubs of Chapel Bill: H. R. Totten. 



There are seventy-two species of native trees 

 found in the Chapel Hill neighborhood. In this 

 number there are fourteen oaks: Quercus alba L., 

 Q. stellata Wang., Q. lyrata Walt., Q. Michauxii 

 Nutt., Q. prinus L., Q. ruba L., Q. palustris 

 Mueneh., Q. velutina Lam., Q. falcata Michx., Q. 

 pagodaefolia (Ell.) Ashe, Q. marilandica Mueneh., 

 Q. nigra L., Q. phellos L. A hybrid, probably be- 

 tween Q. phellos L. and Q. falcata Michx., is also 

 found. This is the only station for the Pin Oak 

 (Q. palustris) in North Carolina. There are seven 

 hickories: Bicoria ovata (Mill.) Britton, B. caro- 

 lina-septentrionalis Ashe, B. microcarpa (Nutt.) 

 Britton, E. glabra (Mill.) Britton, B. pallida Ashe, 

 B. alba (L.) Britton, and B. cordiformis (Wang.) 

 Britton. 



There are sixty native shrubs. A few of the 

 most interesting are: Nestronia umbellata Raf., 

 Bydrangea arborescens L., Euonymus atropur- 

 pureus Jacq., Ascyrum stans Michx., Rhododen- 

 dron catawbiense Michx., Fothergilla major Lodd., 

 Bobinia nanna (Ell.) Spach., Gaultheria procum- 

 bens L., Gaylussacia baccata var. glaucocarpa 

 (Robinson) Mackenzie, and Symplocos tinctoria 

 (L.) L'Her. 



On the Sexuality of the Filament of Spirogyra: 



Bert Cunningham. 



If zygotes occur in both filaments as the result 

 of scalariform conjugation, the filament is said to 

 be bisexual. This condition is called cross conju- 

 gation. All cases reported thus far have been 

 considered as abnormalities on account of their 

 rareness. The writer collected a species in cross 

 conjugation in April, 1915. It has been tenta- 

 tively identified as S. inflata. Professor G. S. 

 West verifies this classification. This shows that 

 bisexuality of the filament does occur in the genus. 

 Bisexuality is due to retarded reduction. In 

 scalariform conjugation reduction occurs in the 

 zygote with the loss of three nuclei, while in lat- 

 eral and cross conjugation, reduction takes place 

 in the filament and no nuclei are lost. The essen- 

 tial difference between lateral and cross conjuga- 

 tion is that the cells may continue to divide after 

 reduction in the latter, while they do not in the 

 former. In this respect the filament of Spirogyra 

 which cross conjugates is homologous with the 

 sporophyte of higher plants. 



The Diorites of the Chapel Bill Stock: John E. 

 Smith. 



