128 
Loa papionis n. sp. 
Table V. 
Differential leucocyte count in six baboons examined shortly before operation. 
200 cells counted. 
Findings at autopsy 
Polymorphs 
Lymphocytes 
Hyalines 
Eosinophiles 
Basophiles 
No. 
1. Marked Loa infection; no other 
parasites found 
80-5 
130 
60 
0-5 
00 
No. 
2. Loa , Agchylosioma, Physaloptera, 
Oxyurus and Trichocephalus 
54-0 
310 
120 
20 
10 
No. 
3. Slight Loa infection; many 
Physaloptera ... .... 
62-5 
24-5 
110 
1-5 
0-0 
No. 
4. Many Physaloptera and also a 
Taenia ... ... ... ... 
42-0 
35-5 
150 
7-5 
00 
No. 
5. Mesentery heavily infected with 
larval Porocephalus 
48-0 
37-5 
90 
50 
0-5 
No. 
6. No parasites found 
420 
40-8 
150 
2-0 
10 
C. A Comparison op Certain Biological Phenomena in the Development 
of Loa papionis and L. loa. 
A short account of Loa loa. This parasite has been known in equatorial 
Africa for hundreds of years. The adult worm is usually found under the skin, 
where its presence may give rise to localised and temporary oedemas—the 
so-called “Calabar swellings”; it is sometimes met with in the eye—more 
especially under the conjunctiva—and in these situations is also liable to 
cause local symptoms. After the death of the host it is usually met with under 
the skin, but has been occasionally discovered in the pericardial and peritoneal 
cavities; its presence in the cranial cavity has also been reported by Brune- 
tiere (1913) who suggests the possibility of its having been the exciting cause 
of an attack of hemiplegia. Infection in man is usually associated with a 
considerable degree of eosinophilia, 40 to 50 per cent, of eosinophiles being 
quite common. As a rule, the larvae are only found in the peripheral circulation 
during the daytime, but this diurnal periodicity may be lost under certain 
abnormal conditions. Three to four years are supposed to elapse between 
infection and the appearance of the larvae in the blood of the definitive host. 
The larvae have been shown by Leiper (1912) to undergo a further stage of 
development in the salivary glands of certain West African tabanid flies 
belonging to the genus Chrysops ; these flies bite exclusively during the daytime. 
The distribution of Loa papionis in P. cynocephalus. Adult L. papionis were 
found in ten out of fifty-five autopsies. Their favourite haunts were the 
subcutaneous tissues overlying the serratus magnus, the trapezius and the 
upper part of the latissimus dorsi muscles, together with the axillary folds 
and the region of the neck; I seldom noticed them in the inguinal or pubic 
regions or under the skin of the limbs, and never succeeded in finding them 
either in or near the eyes or in the serous cavities. However M. Bruck, who 
had previously performed several hundred autopsies on these animals with 
a view to excluding the presence of tuberculosis, etc., showed me the parasites 
he had found and gave me the filariae for identification. Six out of the seven 
