30 

 BIvOOD AND LYMPH. 



LABORATORY WORK FOR THE WEEK. 



References : 



Points for Quiz : 



Laboratory Report . 



Due : 



Go to the delivery desk with two clean slides for 45 and 46 now 

 in balsam ; place a small drop of the balsam on the slide, and cover. 



Obtain from the desk 48, spread on a cover-glass ; stain as 

 directed below and mount in balsam. 



To economize time, next prepare 42 and 43. 



Obtain 47 at your second period. 



HUMAN BLOOD. 



40. Fresh blood. Flame a needle and after it is cool, prick 

 the finger near the nail-bed (best) or the .side of the finger ; wind a 

 handkerchief around the base of the finger and press the finger with 

 the other hand ; a drop of blood will be obtained. Or, you may dis- 

 infect the needle of a haemospath and with it obtain the blood more 

 quickly and easily (§ 120). Touch a cover-glass to the large drop 

 so obtained and place it upon a slide, blood side down. The drop 

 of blood should be large enough to easily fill the space under a 

 cover-glass. Seal the preparation at once with castor oil. 



Study the corpuscles carefully, noting the form as determined 

 by observing the face, profile and oblique views ; the corpuscles can 

 be made to turn over by pressing gently on one edge of the cover- 

 glass. Observe that most of the corpuscles are arranged in rolls or 

 rouleaux. Here and there may be seen a leucocyte or white blood 

 corpuscle. 



41. Action of reagents. Obtain a large drop of blood as in 

 40 ; ascertain the effect upon fresh blood of four reagents as given 

 below. Since this will take some time and needs fresh blood it may 

 be necessary to prick the finger more than once. 



(a) Normal salt solution. Place upon a clean slide a small 

 drop of fresh blood and add to it a small drop of normal salt solu- 



