246 THE AMERICAN MONTHLY [Aug. 



in strong alcohol, after injecting it with the alcohol as 

 just described. Imbed in gum, stain with picro-carmine, 

 mount in glycerine. 



Nerves of imstriated uiiiscles. — The frog's bladder 

 should be used to show the nerve endings in unstriated 

 muscles. Distend the bladder (as already described) 

 with the boiled gold chloride and formic acid. Tie, 

 remove the bladder, and put it for 25 minutes in the gold 

 solution. Then open the bladder, wash, and reduce the 

 gold in darkness for 24 hours in the i formic acid. Ex- 

 tend with the inner surface upward, brush gently to 

 remove the epithelium, and mount in formic acid glycer- 

 ine. . . . 



THE LYMPH. 



The simplest way to collect the lymph is to take it 

 from the dorsal lymphatic sac of a frog by means of a 

 fine pointed pipette. Select a vigorous frog, fasten it by 

 the feet and carefully remove the skin of the back. With 

 a finger of the left hand press on the dorsal region to 

 force the lymph to a determined spot. By a quick 

 movement thrust in the point of the pipette which will 

 partly fill itself ; more may be sucked up. The frog may 

 be curarized, and the lymph taken from the dorsal sac. 

 By curarization the lymphatic sacs are filled by such a 

 quantity of lymph that the tongue hangs out of the 

 mouth. To obtain the lymph, prick the sac with a fine 

 pointed pipette. 



To prepare a drop of lymph. — ....Put a drop on a 

 slide. Expose for 5 minutes to osmic acid vapor, stain 

 with alum carmine, cover, mount in neutral glycerine 

 which is allowed to run under slowly to replace the alum 

 carmine. This preparation shows in a remarkable way 

 the varied forms of nuclei. If the action of the osmium 

 is prolonged, the fatty granules in the white corpuscles 

 will be blackened. 



Put a drop of lymph on a slide, cover, and allow the 



