496 H. B. FANTHAM. 



site. Laveran's method gives the best results when successful, 

 though it is a little difficult to manipulate and somewhat un- 

 certain. Methyl alcohol fixes more sharply and rapidly than 

 ethyl (absolute) alcohol. 



Other blood-films and smears of organs were fixed with a 

 mixture of mercuric chloride (two parts) and absolute alcohol 

 (one part), or with osmic acid, and then stained with a dilute 

 acidulated solution of Delafield's heematoxylin followed by 

 eosin. The staining is slow, at least twenty-four hours being 

 necessary, but the fixation is superior to that obtained with 

 alcohol alone. 



I also used, on a few occasions, a slightly alkaline solution 

 of methylene blue, after fixation with absolute alcohol. Por- 

 tions of liver, kidney, and spleen were fixed in formalin, 

 embedded in paraffin and sectionised. Affixed to slides, sec- 

 tions of these organs were placed in a dilute aqueous solution 

 of Leishman's stain for about twelve hours (vide Christophers 

 [4] and Grraham Smith [14]), then treated with a dilute solu- 

 tion of acetic acid (1 volume of acid to 500 of water) for a 

 short time till pink, washed in distilled water, rapidly dried, 

 then immediately moistened with xylol and mounted in balsam. 

 Unfortunately, formalin is not a satisfactory fixative for these 

 tissues, causing shrinkage. 



Most of the observations hereafter recorded were made on 

 material stained by the Laveran-Plimmer or Leishman 

 methods. 



III. Occurrence of the Parasite in the White Rat. 



The parasites were rarely met with in the peripheral circu- 

 lation, judging from observations on blood-smears from the 

 tail of infected rats or from scrapings of the ulcers on the 

 ears. On an average about 1 per cent., or rather less, of 

 these erythrocytes were infected. 



In smears of the internal organs — as the liver, kidneys, 

 spleen, bone-marrow, lung, heart-muscle, and brain — the 



