and Laboratory Methods. 1537 



CYTOLOGY, EMBRYOLOGY, 



AND 



MICROSCOPICAL METHODS. 



Agnes M. Claypoi.e, Cornell University. 



Separates of papers and books on animal biology should be sent for review to 



Agnes M. Claypole, 125 N. Marengo avenue, 



Pasadena, Cal. 



CURRENT LITERATURE. 



Cloetta, M. Kann das Medicamentose Eisen The white mouse was used for the 

 nur im Duodenum resorbirt werden ? Arch. . ^. . ,^, ^ ^ • 1 



f.Exp. Path. u. Pharm. 64: 363-367. 1900. investigation. The form of iron used 



was a specially prepared iron nuclein. 



The animals were fed for two weeks on a food poor in iron ; then the alimentary 



canal is to be considered free from iron. For several days succeeding, the food 



was mixed with iron nuclein. The animals were killed with ether, the intestine 



hardened at once in absolute alcohol, and subsequently treated by Quincke's 



method (see Arch. f. Exp. Path, and Pharm. 37: 183). 



After staining with ammonium sulphide it was found necessary to let the 



tissue lie in glycerin before examination, since the granules became more distinct. 



An aqueous solution of safranin, which is not changed by alkalies, was used for 



a double stain. The dark green granules stood out markedly from the yellow 



red protoplasm. In applying the Berlin blue reaction it is necessary to put the 



section first into weak alcohol containing hydrogen dioxide, for 24 hours. The 



intestine hardened in absolute alcohol was cut into 1 cm. pieces. These were 



embedded in paraffin, and the whole canal thus cut serially. All preparations 



proved that the iron reaction extended far beyond the limits of the duodenum. 



E. J. c. 



Wilson, J. T. -^ A New System of Obtaining r^^^ method was suggested while using 



Directing Marks in Microscopical Sections °° ° 



for the Purpose of Reconstruction by Wax- the Born-Peter process, and is a modifi- 



plate Modeling. Zeit.f.wiss. Micros, u. f. ^^^^^^ ^f ^^is in the following way: 



Mikros. lechn. 17: 169-177, 1900. _ ° ■' 



Instead of depending entirely upon the 

 filling of ruled lines in a glass plate with pigment, darkly colored, perfectly 

 straight organic filaments are placed in the paraffin together with the tissue to 

 be embedded. The materials used were some of the long, slender root bundles 

 of the human cauda equina ; the intraspinal roots of the fifth sacral and coccygeal 

 nerves are very long and fine, but if more delicate strands are required they may 

 easily be separated from other nerve roots. The absence of branching and 

 uniform caliber, together with their delicacy, make these very favorable for the 

 purpose. Portions of such bundles of 10-12 centimeters in length are suspended 

 by a thread, and carry on a thread at the other end weight enough to keep the 

 strand perfectly straight after immersion in fluid, but not enough to stretch it. 

 These pieces are now hung in a vessel of 1 per cent, osmic acid to blacken the 

 myelin of the nerve fibers. Then they are carried in a like manner through the 

 alcohols and xylol, and infiltrated with paraffin in a test tube. These strands 



