Dept.] NATURAL SCIENCES Or PHILADELPHIA. 
13 
pigment cells identical with those of the pigmentary layer of the scale. The 
same plant occurred, though less abundantly, on all the discolorations above 
referred to. The plant resembled more closely the Torula cerevisia than any 
other. Like it, it was composed of cells with distinct nuclei, isolated, or dis- 
posed in rows, the terminal cells of any row being always of diminished size. 
But it diifered from the Torula in presenting a distinct greenish hue. 
He has been unable to find it figured in any of the books. 
Dr. J. H. Slack alluded to the fungous growth sometimes met with on the 
sides of fishes, and not unfrequently fatal to them. 
Dr. Leidy remarked that this had been ascertained to be the Aclilya 
prolifera; a mycelium, with processes terminating in capsules, which emit 
ciliated and contractile sporules. Weakness of the fish appears to predispose 
to the attack. It is often found on the gold-fish. 
Mr. Queen exhibited a series of beautiful micro-photographs, prepared by 
Mr. Rehn, presenting views of blood, spicula of sponge, Acarus scabiei, &c. 
Dr. J. C. Morris related the particulars of a case of extra-uterine pregnancy, 
which occurred in the practice of a friend of his, and which will be given to the 
profession in a short time through a medical journal. The foetus remained four 
years in a sac within the abdomen ; at the close of this time a fistulous connec- 
tion was established with the rectum, and the child (of eight months) was 
brought through the anus by the aid of narrow-blade d forceps. 
Dr. Morris also called the attention of the Department to the fact stated by 
Dutrochet, that the endosmotic current takes place with great rapidity from an 
acidulated fluid towards a neutral or slightly alkaline one. The amount of 
acidity exercises a marked influence upon the current ; and if it be considerable, 
destroys it altogether. We are more in a condition now to see the application 
of this fact in the economy of digestion, than when it was believed that all of 
the food, after being ehymified in the stomach, was sent to the intestines to be 
converted into chyle, prior to its absorption into the circulatory system. It 
may be readily conceived that the gastric mucous membrane secretes, especi- 
ally during digestion, a watery fluid containing a ]3rinciple capable of splitting, 
by a sort of fermentation, into lactic acid, such a process being rendered still 
more probable by the considerable amount of atmospheric air which finds its 
way to the stomach, mixed with the saliva and food. The presence of this 
acid will fully account for the occasional occurrence of free muriatic acid, as 
chloride of sodium is readily decomposed by it at an elevated temperature into 
lactate of soda and muriatic acid ; and the neutral phosphates may in the same 
way be rendered acid. This would then account readily for the occurrence of 
the free acid in the gastric juice ; while the free acid would again promote a 
rapid current into the blood-vessels of the fluid now charged to a greater or 
less extent with the nitrogenised elements of the food. 
An explanation is thus aflbrded also of the nausea and vomiting produced 
by an excess of free acid in the stomach, quantities of fluid being thus 
evacuated sometimes, which almost exceed credence. In this case the excess 
of SiOidi prevents the endosmose of the fluid into the blood-vessels, and causes it 
to accumulate, while the fresh exudations undergo the same change ; until, 
finally, the overburdened stomach disgorges its troublesome load. 
If we next consider the acid fluid of muscles as opposed to the alkaline 
capillary fluid we have a similar condition of things manifested ; and the con- 
centrated arterial blood becomes loaded with the water, carbonic acid, and 
other products of muscular disintegration, a counter-current meanwhile carry- 
ing albuminoid material to the fibrilla for their renovation. Here we may find 
the explanation of the increased nutrition of a muscle that is frequently exer- 
cised ; the very act of destruction of the tissue by its contraction, causing the 
endosmotic currents to flow with increased rapidity. 
There is some reason to believe, that all secretions are neutral or alkaline 
1858.1 
