ADDITIONS. 



P. 160, \ 260. For handling collodion sections the better quality of white tissue 

 paper sold by stationers has been found excellent. It is worth while to have it cut 

 into pieces about 60 X 50 mm. 



Pp. 171, 179, ' 292, 296, 311. For 

 a laboratory it has been found ad- 



NO. Sf 



c/f 



Jb Lit 



-10 fl 



tr 



2m 



& 



f 



DATE 



Oct 



*m 



vantageous and economical to furnish 

 the students with gummed labels for 

 their preparations. The form used is 

 shown in the accompanying figure. 

 Isabels of this kind can be bought in 

 five thousand lots for 35 to 40 cents 

 per thousand. 



Also for temporary storage, and for 

 sets of preparations to be issued to 

 students, inexpensive slide drawers fit- 

 ting the lockers have been prepared. 

 The accompanying figures indicate the 

 consturction. These in sizes which 

 will hold 50 slides (30 x43 cm.) cost 

 from $\2 to $15 per 100. 



& 



-a 



P. 175, § 258. Grades of Alcohol. It has been found by careful tests that quite 

 accurate percentages of alcohol may be obtained by mixing water and alcohol as 

 follows : Pour alcohol into a graduate until the volume of alcohol corresponds to 

 the desired percentage. Add water until the volume in cubic centimeters corres- 

 ponds to the original percentage of the alcohol used. For example, to get 67% 

 from 95$ alcohol, pour 67 c.c. of 95$ alcohol into a graduate, and add sufficient 

 water to bring the volume up to 95 c.c. For 50% alcohol from 75 #, put 50 c.c. 

 of 75% alcohol in a graduate, add sufficient water to make the volume 75 c.c. 

 From the change in volume it does not answer to mix given volumes of water and 

 alcohol in these cases. In the first case, if one mixed 75 c.c. of 95^ alcohol and 

 20 c.c. of water the resulting mixture won d be over 75 % ; but if sufficient water 

 is added to bring the volume back to the original percentage more than 20 c.c. of 

 water is added, that is enough more to compensate for the shrinkage, and the 

 result is approximately accurate. 



P. 175, \ 299. In case preparations are to be kept some time in alum water, 2% 

 of chloral hydrate should be added to prevent mold. 



P. 216, \ 360. For lettering diagrams, the so-called "easy sign markers" 

 have proved very satisfactory. 



