lS-i8.J 43 



discovering that the female was still in the act of parturition; a rennaining 

 young one was found in the vagina, within half an inch of the external surface. 

 It was moving, head downwards, among a reddish-brown mucous mass, such as 

 had been previously observed in the uterus of a female already referred to. 

 There was not even the rudiment of a placenta. If it had previously existed, it 

 must have been ruptured in the passage of the fcEtus, and escaped my most care- 

 ful search. I was however under an impression that I discovered the slight 

 rudiment of an umbilical cord. The nostrils were open ; the lung-^ were filled 

 with air ; and, on a subsequent experiment, they were observed to float on the 

 surface of water. On dissecting the uterus it was found flaccid and nearly 

 empty, a slight brown mucus on the sides only being visible. 



On the afternoon of the same day I had the remaining female destroyed. On 

 dissecting down to the uterus, I found it greatly distended — full of young, and, 

 as t then supposeil, near the period of production. There was a constant but 

 irregular motion in the various parts; and I felt confident that I would now be 

 furnished with the long sought for opportunity of making a thorough investigation 

 of the various particulars that required farther elucidation. I concluded, how- 

 ever, previously, to have a drawing made of the uterus as it presented itself in 

 this state; this consumed the remainder of the evening. As the weather was 

 warm I made a slight incision in the parts, and placed the whole in alcohol. On 

 the following morning, when, with a scientific friend, we entered on the exami- 

 nation, I was greatly disappointed and mortified, to find that the whole had been 

 so much dissolved by the alcohol that we could make no satisfactory examina- 

 tion. The young were lying in broken fragments in the midst of the unctuous 

 and now considerably diminished mass. I now can scarcely suppQse that the 

 motion I had observed for an hour while the drawing was in progress could have 

 been any other than a muscular contraction and dilation of the different parts of 

 the uterus itself, and not of the young, which were evidently not sufficiently 

 advanced to have occasioned it. 



I would here observe that where the outward integuments of animals are so 

 very tender as those of young opossums a few days previous to their birth, it is 

 advisable to dilute the alcohol to more than half its original strength, as I find 

 the young one that was fully formed, taken from the mother a few moments 

 before birth by the Caesarean operation referred to, has been preserved in good 

 order in alcohol thus diluted. 



In conclusion I will yet add a brief summary of the present state of our know- 

 ledge of the natural history of an animal, whose anatomical structure and peculiar 

 habits have led to the adoption of many vulgai errors, and produced several con- 

 tradictory theories among physiologists. We will thus be enabled to see what 

 important points still remain for farther investigation, and will at the same time 

 be gratified to observe that, although our progress in the investigation of a sin- 

 gularly perplexed subject has been very slow, yet there has been a gradual 

 advance in our knowledge, leading us to the conviction, that in a very few years 

 the history of the opossum will be as correctly and familiarly known to the 

 community at large as that of the hare or squirrel. 



1. The interesting group of the Marsupialia has recently been arranged by 

 Owen into five tribes and families, and sixteen genera : these include about 

 seventy known species, to which additions are continually making ; the Virginian 

 opossum being, however, the only species known in the United States. The 



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