1899J MICROSCOPICAL JOURNAL. 283 



taneous oxidation in light and air with changes of color; 

 and, according to my observations, its use is more con- 

 venient for the described zone- reactions than for experi- 

 ments in watch glasses or dishes, where greater surfaces 

 get into action. It is, moreover, obvious that this special 

 experience cannot interfere with the certainly desirable 

 use of the guaiaconic acid, as being the active constituent 

 of the resin, in the numerous other guaiacum-reactions. 

 I connot but feel convinced that the reactions with gua- 

 iacum resin have not, in all respects, met with the consid- 

 eration they deserve, neither in general nor in medical 

 and pharmaceutical chemistry, so I thought it advisable 

 to publish this little contribution to the question in this 

 convenient place. — Atnerican Journal Pharmacy. 



Strassburg (Germany) Pharm. Institute University. 



Method for Preparing Nucleated Blood in Bulk for Class 

 Demonstration. 



T. E. OERTEL. 



No book on microscopical technique which I have been 

 able to consult gives amethod for preparing blood in bulk. 

 For class demonstration it is obvious that by having on 

 hand ready prepared material the work will be greatly 

 facilitated and a uniformity of result assured which could 

 not be expected from the faulty manipulations of untrain- 

 ed students to whom blood is usually given for study 

 early in their histological course. 



It is much more convenient for the teacher to dispense 

 his preparation from a small vial than to be compelled to 

 make "smears" for a large class. ''Smears" are also of- 

 ten unsatisfactory by reason of agglutination or crena- 

 tion of the corpuscles, excess of serum and the formation 

 of fibrin and much care is required in their proper fixa- 

 tion, by the usual method of heat, in order that the re- 

 sult be not disastrous. 



