and Laboratory Methods. 2093 



7. Orange G. — Ehrlich recommends a saturated watery solution of orange 

 G. as a stain for the acidophile granules of the blood. 



C. Double Staining with Add and Basic Stains. 



1. Aurentia and Methylen Blue. — Miiller stained dry blood preparations 

 that had been heated two hours at 115° to 120° C. with aurentia followed by 

 methylen blue. A drop of a concentrated alcoholic solution of aurentia is 

 placed on the preparation, spread, and allowed to evaporate. The preparation 

 is treated in the same way with a second and a third drop. It is then washed 

 in alcohol until no more stain dissolves out, and stained in a strong watery solu- 

 tion of methylen blue for from 5 to 10 minutes, or more, then washed in water, 

 dried in the air and mounted. Red corpuscles are stained yellow, nuclei of 

 nucleated red corpuscles green, nuclei of resting mono-nuclear leucocytes pure 

 blue. 



Bizzozero (1890) used aurentia and methylen blue for recognizing 

 hemoglobin in the early development of red corpuscles in birds. 



Castellino (1892) employed aurentia and methylen blue for the study of 

 the degeneration of the red corpnscles. 



2. Eosin and Haematoxylin. — Ehrlich's eosin and haematoxylin mixture is as 

 follows : 



Eosin (cryst.), - - - - - 0.5. 



Haematoxylin, - 2.0 



Absolute alcohol ----- 100.0 



Distilled water, ----- 100.0 



Glycerin, ------ lOO.O 



Glaciel acetic acid, - - - - ' 10.0 



Alum in excess. 



This mixture must ripen some weeks before use. 



Preparations should be fixed in absolute alcohol or by short heating, and 

 stained several hours. The staining solution should be very carefully washed 

 off. Haemoglobin and acidophile granules stain red, nuclei haematoxylin color. 

 Orange G may be substituted for eosin in this mixture. 



3. Eosin and " Methylanilingruen." — More and Stowell (1884) stained blood 

 preparations with eosin (1 : 50 water and 50 alcohol), dried, stained with 

 " methylanilingriin " (1 : 100 water), dried, and mounted. 



Massachusetts State Board of Health. ErneST L. Walker. 



LABORATORY OUTLINES. 



For the Elementary Study of Plant Structures and Functions from 

 the Standpoint of Evolution. 



XX. Hydrodictyon reticulatuni (L.) Lag. Water-net. Order, Hydrodictyales. 

 Family, Hydrodictyaceae. 



The water-net forms a large body, which is common in summer and autumn in 

 ponds and canals. It may often be collected in great quantities along the 



