THE ENVOY o1D 
and his imitators). His own speculations are not particularly 
prescient or original, and appear to have but little relation 
to modern conceptions. I regard Goiffon’s dissertation as 
historically negligible: in any case, it was without influence 
upon the course of bacteriology or protozoology. 
I cannot omit to mention, in the present connexion, an 
extraordinary effort in pseudo-microbiology published just 
after Leeuwenhoek’s death by a French quack doctor. This 
charlatan, who wrote under the initials ‘““ M.A.C.D.”, pretended 
to discover the “insects” responsible for all diseases, and to 
cure his patients by eradicating them by secret methods.’ 
He claimed to be following the system of an English physician 
who had learned of it in Persia: and he gave a comical 
description—accompanied by the crudest cuts—of no less than 
91 absurdly-named “little insects” which cause as many 
complaints. This imposture was exposed by Vallisneri,” in a 
posthumously published letter which is not generally known. 
I need make no further reference to it: I mention it only 
because certain learned authors have apparently taken this 
obvious bit of charlatanry for a serious contribution to 
microbiology or for genuine satire.’ It was certainly neither. 
There is no need, for present purposes, to trace in detail 
the history of our knowledge of Leeuwenhoek’s “little 
animals’? down to modern times. We are here concerned 
merely with the beginnings of protozoology and bacteriology : 
yet to see them as beginnings we must cast our eye also upon 
the later historical landmarks. As everyone knows, scant 
progress was made in the century following Leeuwenhoek’s 
death; though it is worth noting that the first scientific 
1 See M.A.C.D. (1726, 1727). I quote him (as is customary) under 
these initials, though his real name, according to Vallisneri (1733), was Boil. 
From the “ Privilége du Roy” at the end of his work, where the author 
is referred to as ‘le siewr A.C.D.’, it seems that the initial M. stands 
for Monsieur. Consequently, he ought properly to be catalogued as 
Pa ey ag 
“See Vallisneri (1733), Vol. III, p. 218. It is here explained how “Mr 
A. C. D.’ was able to impose upon his patients by showing them the 
“insects”? in their blood or urine through a trick microscope—which 
apparently exhibited the object mounted before it, but really showed 
protozoa out of an infusion. 
* Cf. Lesser (1738), Ehrenberg (1838), Bulloch (1930), ete. 
