1630 Journal of Applied Microscopy 



weeks reappear in practically normal completeness, apparently then being sub- 

 served by some nervous mechanism which under normal circumstances contrib- 

 uted very little to their performance. 



A final section is devoted to the " Pathology of the Sympathetic." The 

 plates illustrating the paper are excellently done. r. p. 



Ascbkinass, E., and Caspar!, W. Ueber den _,, ^ , . . . . 



Einfluss dissociirender Strahlen auf organ- The purpose of this mvestlgation was 

 isirte Substanzen, inbesondere liber die tO determine the physiological action 

 bakterienschadigende Wirkune der Bee- , ,. . . , , , 



querel-Strahlen. Arch. f. d. ges. Physiol. O^ radiations of short wave lengths, 

 86: 603-618,1901. including Rontgen, kathode, and Bec- 



querel rays. The first method used was the study of the amount of gaseous 

 metabolism in frog muscle in tubes exposed to Rontgen and Becquerel rays as 

 compared with that in muscle similarly treated but not exposed to the action of 

 the rays. The results from these experiments showed that these rays caused a 

 lowering of the vital activity of the muscle as indicated by the amount of the meta- 

 bolism. The experiments were not performed in sufficient number to be 

 absolutely conclusive, however, and attention was turned to the effect of Becquerel 

 rays on the growth of Micrococcus prodigiosus, cultures on nutrient agar. The 

 preparation of a typical experiment was as follows : the under surface of the 

 cover of a Petri dish was coated with agar and the center of this was inoculated 

 with M. prodigiosus. Directly below the point of inoculation on the bottom of the 

 Petri dish was placed the brass capsule containing the radio-active substance 

 (Ig. of barium-radium-bromide crj'^stals). The culture was exposed from one to 

 five hours to the action of the rays. It was found that the radiations of the sort 

 that are only slightly absorbed in their passage through any medium were without 

 effect on the growth of the bacteria cultures. Growth proceeded as well as in 

 the controls. On the other hand, the rays which are absorbed in high degree 

 caused a complete inhibition of the growth of the colonies. The experiments 

 were varied in such ways as to prove that the effect is due only to the action of 

 the Becquerel rays on the bacteria themselves. The authors hope to carry on 

 similar experiments with cultures of pathogenic bacteria with a view of possibly 

 finding some therapeutic value in the use of Becquerel rays. r. p. 



Viguier, C. Fecondation chimique ou parthe- Viguier finds that unfertilized eggs of 

 nogenese? Ann. Sci. natur. Zoo). Ser. the echinoderms Sphccrechifius granu- 

 ' ' ' ' J ■> ^ • /aris, Toxopneustes lividus and Arbacia 



pustulosa taken at Algiers will develop parthenogenetically in normal sea water, 

 or are, as he puts it, " naturally parthenogenetic." The MgCU solutions which 

 Loeb found to be effective in producing artificial parthenogenesis in the eggs of 

 starfish and sea urchins taken in this country, have, according to Viguier, a retard- 

 ing effect on the development of the eggs of the Algerian species, and may even 

 inhibit entirely the " natural parthenogenesis " which would under ordinary cir- 

 cumstances occur. The plutei from parthenogenetically developed eggs of 

 Arbacia are found to be different from those arising from normally fertilized eggs 

 in the lengths of the arms and the angles included between them. The author 

 very strongly condemns the use of the eggs of these species which will naturally 

 develop parthenogenetically, for the study of artificial parthenogenesis. R. p. 



