THE NATURE OF HUMAN TICK-FEVER 
35 
of egg laying was not observed. The length of. the tick before feeding was 
7mm.; after engorgement 11.50mm. The weight before feeding was 
.0270grms., after engorgement .2602grms., or an increase of about ten 
times her original weight. This was not a very marked increase, as com- 
pared with certain other species of female ticks, which are known to increase 
to about thirty times their original weight after engorgement. Batches of 
eggs were laid on the following dates — during the night : — 
June 29. — First batch of 17 eges. These were found in a little cluster at 
the bottom of the Petri dish. 
July 2. — Second batch of 51 eggs laid. These were protected for a few 
days beneath the body of the parent. 
July 10. — Third batch of 26 eggs laid. These were also protected by the 
parent for a few days. 
Development of the First Batch of Eggs. 
June 30. — First day — subcutaneous reticulation evident. Poles slightly 
cloudy. 
June 31. — Second to fourth day — no change. 
July 3. — Fifth day — subcutaneous reticulation more distinct. 
July 5. — Sixth day — form decidedly flattened. Legs and capitulum of larva 
showing faintly through the cuticle of the egg. 
July 6. — Seventh day — Form unchanged. Legs more evident. 
July 7. — Eighth day — " Arrow-shaped, patch of secretion " formed beneath 
the cuticle of the larva, near anal orifice. 
July 8. — Ninth day — egg shell split. Larva fully formed. 
July 14.— Tenth to fifteenth day — cuticle of both egg and larva increasing 
in opacity, finally forming a dull white disc. 
July 15. — Sixteenth day — nymphs hatching. Several examples were seen to 
escape from the larval exuviae anteriorly. 
Development of the Second Batch of Eggs. 
Although these were laid four days later than the first batch, some of 
the nymphs appeared simultaneously with those of the first batch — i.e., on 
July 15. 
Development of the Third Batch of Eggs. 
These were laid twelve days after the first batch, or eight days after the 
second batch, and the first nymph appeared on July 18, just three days 
later than the earliest appearance of the nymphs from the first batch. 
It should, however, be noted that the nymphs from all three batches 
were quite erratic in their appearance, as examples from each lot of eggs 
continued to emerge over a period of twelve days, the last appearing on 
July 27th. 
