and Laboratory Methods. 1589 



Neisser and Wechsberg, Ueber das Staphylo- -pj^g authors have undertaken the study 



toxin. Zeit. f. Hyg. 3o: 299, 1901. / 



of the question whether the bacteria 

 going under the name of Staphylococcus produce toxic products. The pro- 

 duction of toxines by the well known pathogenic forms of Streptococcus has 

 previously been subject to much experimentation, but the Staphylococci have 

 been generally neglected. The author studies both of the common species of 

 this genus, the Staph, aurus and Staph, albus. His method is to cultivate the 

 organisms in proper media and then, after filtration, to test the filtrate for the 

 presence of toxic products. His conclusion is that both of these species produce 

 toxines, and the toxines produced are identical in both cases. There are two 

 such toxines, one of which produces a dissolution of red corpuscles, called 

 hcemolysin, and the other producing a dissolution of white corpuscles, and called 

 leukocidiii. All tests indicate that the toxic products produced by the two species 

 are identical, inasmuch as they always answer to the same tests. 



The author is further of the opinion that, so far as concerns the production 

 of these toxic products, all of the numerous varieties of Staphylococcus are 

 essentially the same. h. w. c. 



NOTES ON RECENT MINERALOGICAL 

 LITERATURE. 



Alfred J. Moses and Lea McI. Luquer. 



Books and reprints for review should be sent to Alfred J. Moses, Columbia University, 



New York. N. Y. 



Vernadsky W. Zur Theorie der Silicate. (Concluded from November ^ 



Zeit. f. Kryst., 34: 37-66, 1901. \ j j 



ALUMOSILICATES. 



Again we have the salts and " derivatives," the most important part being 

 that of the salts of the alumosilicic acids, for which the general formula is 

 m MO ^n AlgOg "/SiOg, but as experience shows, ?n=Ji, and when m=u^=\, 

 then p=\, 2, 4, 6, and rarely 8, 10, or 12; that is, only the following alumo- 

 silicates have been observed: MgAljSiOg, M2Al2Si20g, M2Al2Si40i2' 



M2Al2Si60i6, M2Al2Sig02o, M2Al2Siio024, M2Al2Sii2028. 



The first of these may be called the group with the chlorite nucleus, and all 

 the others the group with the mica nucleus, for the following reasons : 



(a) There is no known reaction by which alumosilicates with chlorite nucleus 

 can pass directly into alumosilicates with mica nucleus, or the converse. It can 

 only be accomplished by the introduction of " derivatives." 



(Jt) Alumosilicates, with mica nucleus readily pass from one division to 

 another. 



(<r) By weathering, the alumosilicates, with mica nucleus, yield clay ; those 

 with chlorite nucleus do not. 



(cl) Chrome silicates, with chlorite nucleus, are red or rose colored, but with 

 mica nucleus are green, indicating different structure. 



