Am.  Jour.  Pharm.  ) 
February,  1914.  j 
Colloids  and  Crystals. 
71 
T  Journal  of  Amer.  Med.  Assoc.,  September  13,  1913. 
8 "  Observations  on  the  Keeping  Properties  of  Digitalis  and  Some  of  Its  Prep- 
arations," Hatcher  and  Eggleston.  American  Journal  of  Pharmacy, 
1913,  page  203. 
9  Miller  and  Baker,  8th  International  Congress  of  Applied  Chemistry. 
10  Personal  Communication. 
11  Kraft,  Arch,  der  Pharm.,  1912. 
V£  Edmunds  and  Hale,  "  The  Physiological  Standardization  of  Digitalis." 
18  Houghton,  Journal  of  American  Medical  Association,  June  7-10,  1898. 
"Hale,  The  Physiological  Standardization  of  Drugs,  American  Journal  of 
Pharmacy,  191 1. 
16  United  States  Hygienic  Laboratory,  Bulletin  48. 
18 "  Laboratory  Guide  in  Experimental  Pharmacology,"  Geo.  Wahr,  publisher. 
17  Focke,  Arch.  d.  Pharm.,  1903,  241,  page  678. 
18  Hamilton,  "  The  Heart  Tonic  Unit,"  American  Journal  of  Pharmacy,  1912, 
page  97. 
19  Braun  and  Closson,  "  The  Chemical  Constitution  of  Crystalline  Strophan- 
thus,"  Jour,  of  Amer.  Pharm.  Assoc.,  1913. 
20  Reed  and  Vanderkled,  American  Journal  of  Pharmacy,  1908,  page  no. 
21  "  Standardization  of  Pharmaceutical  and  Biological  Products,"  Parke,  Davis 
and  Co. 
22  Hitchens.    Journal  of  Experimental  Medicine,  1905. 
23  Pittinger,  1912  Proceedings  American  Therapeutic  Society. 
34  Hatcher  and  Brodie,  American  Journal  of  Pharmacy,  1910,  page  362. 
25  Eckler,  American  Journal  of  Pharmacy,  October,  191 1. 
26  Hale,  Factors  Relating  to  the  Standardization  of  Digitalis ;  Proceedings  of 
American  Pharmaceutical  Association,  1909. 
27  Hatcher  and  Bailey,  Jour.  Amer.  Med.  Assoc.,  1907,  page  1021. 
28  Lyon  and  Quail,  Jour.  Amer.  Med.  Assoc.,  1910,  pages  455,  459,  508. 
19  Graeber,  Therapeutische  Monatshefte,  1913,  page  581. 
30  Pettey,  "  The  Therapeutic  Virtues  of  Sparetine  Sulphate."    Clinical  Medi- 
cine, Sept.,  1913. 
31  Lewis,  "  Clinical  Electrocardiography." 
52  Faught,  "  Blood-Pressure  from  Clinical  Standpoint,"  page  268. 
COLLOIDS  AND  CRYSTALS,  THE  TWO  WORLDS  OF 
MATTER* 
By  Robert  H.  Bradbury, 
Head  of  the  Department  of  Science  in  the  Southern  High  School,  Philadelphia. 
When  a  solid  is  brought  into  contact  with  a  liquid  the  result 
depends  upon  the  nature  of  both.    There  may  be  apparently  an  entire 
*  Presented  at  the  meeting  of  the  Section  of  Physics  and  Chemistry  held 
Thursday,  April  10,  1913,  and  reprinted  from  Jour.  Franklin  Institute,  Sep- 
tember, 191 3. 
