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114 REPORT—1857. 
GENESIS. 
HETEROGENESIS. 
(Reproductive force acting through 
dissimilar cells, sperm-cells and 
HoMoGENESIS. 
(Reproductive force acting through 
similar cells.) 
A. 
1 
It is represented in— 
Plants by Phytoids. 
. Isophytoids. 
Buds. 
. Allophytoids. 
Bulbilli. 
Bulbs. 
Sporules, &c. 
. Animals by Zooids. 
- Isozooids. 
Gems, or buds. 
. Allozooids. 
Nurses (Steenstrup). 
Agamozooids (Huxley). 
Virgin Aphides (Owen). 
germ-cells.) 
It is represented in— 
A. Plants by 
. Gynophytoids. 
Female flowers. 
Pistillidia, &e. 
. Androphytoids. 
Male flowers. 
Antheridia, &c. 
3. Androgynophytoids. 
Hermaphrodite flowers. 
- In animals by— 
. Gynozooids. 
Females. 
. Androzooids. 
Males. 
. Androgynozooids. 
Hermaphrodites. 
Agamic eggs (Lubbock). 
Drone Bees (Siebold). 
On the Flow of the Lacteal Fluid in the Mesentery of the Mouse. 
By Josrru Lister, F.R.C.S.E. 
_ The objects of the experiments were twofold—Ist, to ascertain the character of 
the flow of the chyle under ordinary circumstances, which he believed had never yet 
been satisfactorily done; and 2ndly, to endeavour to throw some light upon the 
debated question, whether or not the lacteals were capable of absorbing solid matter 
in the form of granules visible to the human eye. In the first set of experiments, a 
mouse having been put under the influence of chloroform an hour or two after par- 
taking of a full meal of bread and milk, the abdomen was laid open by a longitudinal 
median incision, and a fold of intestine drawn out gently so that it might lie ona 
plate of glass under the microscope, the exposed part being occasionally moistened 
with water of the temperature of 100° F. Under these circumstances, the lacteals 
were very readily visible as beautiful transparent beaded cords; the beads corre- 
sponding to the situations of the valves, which were seen to be standing open, while 
chyle-corpuscles moved on through the tubes with perfectly equable flow; as a rule 
equal to about a quarter of that at which the blood moves through the capillaries. 
These observations were frequently repeated, and always with the same result. 
Hence it was clear that the lacteals, though known to be muscular, and richly pro- 
vided with valves, do not, in the mesentery at least, promote the flow of the chyle by 
contraction, rhythmical or otherwise; and that the source of the movement of the ~ 
fluid is some cause in constant and steady operation. It was further observed that 
the chyle-corpuscles were, many of them, already of full size, although at so short 
a distance from the scene of absorption, proving the rapidity with which those © 
corpuscles are elaborated. 
The other set of experiments were performed in the same way, except that some 
coloured material, generally indigo, was mixed with the bread and milk. The ani- 
mals took the mixture readily, and it passed freely along the intestines, but no indigo 
particles were ever seen in the chyle, although, had it been absorbed in the solid 
form, it would have been detected with the utmost facility within the lacteals. It 
might be supposed that the colouring matter had acted as a poison, and paralysed 
the function of absorption; but there was no appearance of this, the chyle flowing © 
just as rapidly as when the mice were fed with simple bread and milk. These facts, — 
though not perhaps absolutely conclusive, seemed to throw great doubt on the pos- | 
sibility of absorption of solid matter by the lacteals. 
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