250 
Drug Treatment of Redwater 
Table showing the time when the cows were treated after the parasites had first 
been found, the time which elapsed between the injection of the drug and 
the disappearance of the parasites, and the time when the parasites re¬ 
appeared after their first disappearance. 
Treated 
Cow No. 
Time in days 
when cow 
was treated after 
parasites appeared 
Time it took 
the parasites 
to disappear after 
drug was injected 
Time when 
parasites reappeared 
1 
1 day 
- 24 hours* 
Blood negative for 18 days. 
2 
2 days 
-45 „ 
„ „ „ 16 „ 
3 
1 day 
-24 „ 
>, ,, „ 6 ,, 
Very few parasites found later, 
none on some days. 
4 
Same day 
9 „ 
Blood negative for 5 days, 1 para¬ 
site found 6th day, none later. 
5 
2 days 
-45 „ 
Blood negative for 6 days when 
observation ceased. 
* The - signs before the numbers denote that the parasites may have disappeared 
some hours earlier than is recorded. 
Note .-—As will be seen by reference to p. 241 the parasites were found microscopically 
in the blood of the Control Cows during 4 to 6 days. The parasites reappeared after 2 days 
in one case, after 8 days in two cases, after 11 days in one case. 
Judging from the facts above recorded, it appears certain that some 
of these cows would have died but for the treatment they received. 
Note regarding degenerative changes in the parasites. 
The single parasites contained in infected corpuscles showed 
evidence of degeneration, as described in P. canis, in consequence of 
the treatment. When these single parasites were grouped according to 
their size into “ large ” and “ small ” we observed the following changes 
in their relative numbers as the result of treatment. (Examination of 
stained films from Cow 1): 
At 12.30 p.m., just before treatment there were 66 % large and 34 % small parasites. 
„ 2.45 p.m., after „ „ 35 % ,, 65 % „ 
„ 4.45 p.m., „ „ „ 36 % „ 64 °/ 0 „ 
After treatment, the large intracorpuscular parasites stained faintly 
in contrast to the small parasites, which stain intensely. At the same 
time a number of conjoined pairs of free pyriform parasites were 
observable which stained faintly, and single degenerated pyriforms 
could be occasionally encountered. 
