66 
MR. BOWMAN ON THE STRUCTURE AND USE OF 
its several constituent parts. The principal of these are well known, and it would 
have diverted attention too much to delineate others, especially as such peculiarities 
are of trifling moment. The accompanying illustrations I have endeavoured to 
execute with scrupulous fidelity after nature. The injected specimens from which 
several of them are taken, are, with numerous others, in my possession, and those 
that can be examined only in a recent state, may usually be prepared with facility. 
I shall now state the results of my injections of the kidney of Man and the higher 
animals by the arteries, veins, and ducts, in order to show their accordance with the 
view I have given of the nature of the Malpighian bodies, and of the vascular appa- 
ratus of the organ. This may be also desirable for purposes of comparison with the 
statements of other anatomists (which, to avoid prolixity, I have not referred to in 
detail) ; and it will, besides, give a full opportunity of testing the correctness of my 
statements, to those inquirers who may be disposed to do so*. 
By the Arteries, the Malpighian Tufts can he injected with great facility , and also, with 
less freedom, the Capillaries surrounding the uriniferous tubes. The Tubes also may 
be injected, by extravasation from the Malpighian tufts. 
The course of the injection to the tufts is direct and free. The arterial tree is of 
small capacity, and there is seldom so much blood in it after death as to impede the 
flow of the artificial fluid. My preparations show this tree injected in various degrees, 
by the double fluid (Plate IV. figs. 1 to 14). In some, the tufts are full, the afferent and 
the efferent vessels are both seen, as well as the communication of the latter with the 
plexus surrounding the tubes (figs. 2, 4, 5, 6). In others, the vessels of the tuft have 
given way under the pressure of the fluid, which has then escaped into the capsule 
and often into the tube also'|' (figs. 4, 9, 10, &c.). Sometimes the injection has 
passed freely and without extravasation through only a portion of the Malpighian 
tuft, leaving the rest filled with blood, which could not have happened to an un- 
branched coil of vessel, as this tuft is by some described^. In these, the afferent 
and the efferent vessels are both injected, but only a fragment of the tuft (fig. 2). 
Sometimes the injected fluid has burst out immediately on entering the first branches 
* It is worthy of notice, as showing both the difficulty of the subject and the uncertain state of our know- 
ledge up to the present time, that Berres, the distinguished Professor of Vienna, in his recently published work 
on microscopical anatomy, maintains the existence of a direct inosculation of the uriniferous tubes with the ca- 
pillary plexus surrounding them. After the description already given, I need hardly say, that this view seems 
to me, for many reasons, altogether untenable. 
f I have great pleasure in stating that my friend Mr. Tomes, three years ago, during his examination of 
numerous kidneys that he had injected, saw two or three examples of this escape of the injection along the 
tube ; of one of which he has preserved a rough outline. Not being able to see it again he gave up the search. 
I have no doubt that he communicated this fact to me in conversation at the time, though I cannot now recol- 
lect his doing so. The first drawing I made of the tube expanded over the tuft, I find dated February 17, 1841 ; 
about which time my interest in the subject was first excited. 
I Of course this never occurs in Birds, where the Malpighian vessel is a coiled ampulla. 
