THE CULTIVATION OF LEISHMANIA INFANTUM AND 
LEPTOMONAS CTENOCEPHALI ON THE TRIPLE-N 
MEDIUM! | 
By LAMBERTO LEIVA 
Assistant Professor of Parasitology, College of Medicine and Surgery, 
University of the Philippines 
INTRODUCTION 
The successful cultivation of trypanosomes on the artificial 
medium of Novy and MacNeal(3) has led in the past to its trial 
for Leishmania. The present inquiry was intended to find out 
what minimal amounts of blood could be used provided the pro- 
portion of agar be altered from that used in the original formula; 
and to what extent different degrees of softness of the whole 
medium would influence the growth of these protozoans. 
MATERIAL AND PROCEDURE 
Strains of Leishmania infantum and Leptomonas ctenocephali, 
which were furnished me through the kindness of Prof. E. E. 
Tyzzer, of the department of comparative pathology, Harvard 
Medical School, were used in these experiments. It was thought 
best to study these two organisms; because, while they have pro- 
nounced morphological similarities, they exhibit distinct biolog- 
ical manifestations, as L. infantum is the etiologic agent of a 
. Severe disease, infantile kala-azar, and the other is apparently 
a harmless parasite in the gut of the common dog flea. 
Two culture media, one containing 2 per cent agar and the 
other 0.5 per cent agar, were used, to which different proportions 
of blood were added. The complete formule of the media are as 
follows: 
Two per cent agar culture medium. 
Agar-agar (grams) 20 
Sodium chloride (grams) 4 
Water (cc) 1,000 
One-half per cent agar culture medium. 
Agar-agar (grams) : 5 
Sodium chloride (grams) 4 
Water (cc) 1,000 
* Received July 1, 1921. From the laboratories of the College of Med- 
icine and Surgery, University of the Philippines, and the Harvard School 
of Tropical Medicine. 179 
