460 
The K^lrloff-Bochf 
were present in the blood of all guinea-pigs—I never failed to find 
them in a guinea-pig if I continued the search for several days. I might 
mention here with regard to the differential counting of leucocytes 
from day to day that the results were quite variable, such variations 
being dependent upon the factors of food, the degree of heat and 
friction applied to the ear just before withdrawing the blood, the 
previous number of times the ear had been cut and how recently; but 
in general the proportion of polymorphonuclear forms to the mono¬ 
nuclear forms is about equal. The mononuclear cells containing 
Kurloff-bodies vary from day to day as much as from 1 to 20 per cent, 
of all the leucocytes. 
To see what effect, if any, might result from keeping guinea-pigs 
free of ecto-parasites I performed the following experiment. Four 
guinea-pigs were thoroughly combed and brushed. Two of them were 
etherized and bathed in ether, alcohol, and acetic acid solution so as to 
kill all lice and eggs and then naphthalin was dusted and rubbed into 
their coat. This treatment was found unnecessary and not so good as 
the daily use of pyrethrum powder blown in amongst the separated hairs 
by an insufflator and the removing of all nits on top of the head by 
rubbing with a solution of 10-20 per cent, acetic acid. The guinea-pigs 
were placed separately in tin buckets which each day were scalded, 
dried, and supplied with dry sterilized saw-dust for bedding. To pre¬ 
vent the guinea-pigs from becoming infested with lice the buckets 
containing the animals were suspended from the ceiling. After a few 
days of such treatment I examined each guinea-pig for ecto-parasites 
with negative results—but to ensure the complete extermination of any 
lice that might have been missed an assistant was detailed to carefully 
examine the pigs and treat them with the powder and fresh dusty 
bedding every morning for several months. It was found that the 
removal of all lice made no appreciable difference in the number of 
Kurloff-bodies present. Two of the females gave birth to young under 
these conditions, and, while the young did not contain the larger, more 
mature Kurloff-bodies, they were found to harbour the smallest form 
of Kurloff-body, i.e. the azurophilic granule. 
During the summer months these four guinea-pigs which were free 
from ecto-parasites were placed in a wet muddy hutch protected by fine 
wire screening and far removed from any source of infestatioti. Within 
a few days many of the mononuclear leucocytes contained from one to 
six azurophilic granules and within a week many of the mononuclear 
leucocytes contained the largest form of Kurloff-body, i.e. the sac, much 
