342 
THE DISCOVERY OF THE COCCIDIA. 
By CLIFFORD DOBELL, F.R.S. 
; ) 
Students of tlie history of Protozoology are generally agreed that the earliest 
recorded observations on the Coccidia are those of Hake (1839). Biitschli 
(1882, p. 490) mentions his work, though he did not see it; and it has been 
cited by Leuckart (1879), Labbe (1896), and several other writers on the 
Sporozoa—including myself (1919)—as the first publication in which coccidia 
are recognizably described 1 . 
Dr Thomas Gordon Hake was a practising London physician. His book 
is now extremely rare, and has probably been seen by but few protozoologists. 
In this work he described the lesions caused by Eimeria stiedae in the rabbit’s 
liver, and gave an account, accompanied by admirable figures, of the un¬ 
segmented oocysts of this parasite. But Hake’s description—though it appears 
to be the first in which any stages of the coccidia themselves were described— 
is not the first account of coccidial lesions in the rabbit: for I find that in the 
previous year (1838) Robert Carswell—at that time Professor of Pathological 
Anatomy at University College, London—published a coloured picture of a 
rabbit’s liver showing the lesions caused by E. stiedae. It is to be found 2 in 
the section devoted to “Tubercle” (last section of the book), on Plate II 
(illustrating this section), Fig. 6; but the lesions shown in the bile-ducts— 
which are partly dissected out—are described in the accompanying letterpress 
as “a beautiful illustration of the seat of tuberculous matter in the liver of 
the rabbit.” The lesions are, however, to my mind clearly those of coccidiosis 
—not of tuberculosis. 
. In his interpretation of his own findings Hake was no happier than 
Carswell. For him the coccidial lesions were not tuberculous, but constituted 
a “carcinoma of the bile-ducts”; while the unripe oocysts which he found 
in them were described as being “a new form of the pus globule,” though 
they were also called more objectively “ovate corpuscles.” Nevertheless, in 
spite of his errors Hake probably deserves the credit of being the first to 
1 Diesing (1851, p. 16) has supposed that sporozoan parasites were seen by Redi in Crustacea: 
but Biitschli, Leger, and other authoritative writers on the Sporozoa, have rejected this supposi¬ 
tion; and after a careful study of the original work of Redi (1684) I consider their conclusions 
fully justified. At all events, I think there can be no doubt that the things which Redi found 
in crabs were certainly not coccidia—whatever else they may have been. 
2 In Carswell’s book the pages are not numbered, nor are the plates numbered consecutively. 
I trust, however, that the particulars given above will suffice to enable anybody to find the figure 
in question. The book itself is rare, and not readily accessible. Carswell is mentioned by some 
of the writers on the Coccidia, but usually without any exact reference to his work. 
