and Laboratory Methods, 



2133 



Wash off excess of stain. Dry between filter papers and mount in balsam as 

 usual. Intracellular clear bodies representing an early stage of the development 

 of the parasite are found in all forms of malarial fever. The clear space seen 

 in many red corpuscles due to the biconcave shape of the cell should not be mis- 

 taken for the malarial organism. In tertian fever a few hours after the chill the 

 ring appears. Pigment usually forms. The rosette and various other forms of 

 the parasite are well stained by these methods. 



The reader is referred to more complete works for further information and a 

 description of the various forms of the parasite. 



SIMPLE PATHOLOGICAL TECHNIQUE. 



Collecting, Fixing and Preserving the Specimen. In ordinary cases the observer 

 desires to make a mounted preparation of the tissue at once and in consequence 

 he is interested only in collecting, fixing, embedding and cutting. To insure 

 uniform and accurate results remove but a small portion of the tissue, not larger 





ES^- 





:^' -. 



Fig. XXIV. — Trichinae encysted in pork Stained with liaematoxylin and eosin. 

 Magnified 150 diameters. 73-hi. objective ; Zeiss projection ocular No. 4. 



than 10 mm. square and 5 mm. thick, a much smaller piece would be better. 

 Two or three pieces from different portions of the tissue (growth or tumor or 

 organ) maybe taken. Do not wash, but drop immediately into some good fixing 

 solution to kill and preserve the tissue elements as in their living condition. 

 There should be six or eight times as much fixing solution as tissue. Ordinary 

 alcohol may be used, but Carnoy's fluid will give much better results and is 

 more rapid in its action. 



It is prepared as follows : 



Absolute alcohol - - - - 60 c. c. 



Chloroform - - - - - 30 c. c. 



Glacial acetic acid - - - - 10 c. c. 

 The tissue should remain in this fluid for four hours. Pour off the Carnoy's 

 fluid and cover the specimens with absolute alcohol, which should remain half 

 an hour. This should be poured off and fresh absolute alcohol used for a second 

 half hour. This process washes out the Carnoy's fluid and finishes the harden- 

 ing of the specimen. It is now ready to embed. 

 Harvey Medical College. WiLLIAM H. Knap. 



