NATURAL SCIENCES OF PHILADELPHIA. 7 



the parent, of all sizes neaily, to that of the latter itself. When the new frond 

 is separated, the parent is observed to appear truncate at the pole of separa- 

 tion with a cup-like concavity, surrounded by a thin hyaline margin, which is 

 sometimes slightly everted. After the establishment of the cup, a succession 

 of new fronds appear to be produced from it, and may be observed in diftcrent 

 fronds in all stages of growth. The new fronds are slightly pedicellate, and 

 the offspring of these appear to originate close to the pedicel. Size of the 

 full grown frond from ;j to i a line in depth and breadth, with the length 

 slight!}' greater. 



Outer epidermis composed of hexagonal cells in outline, with an abundance 

 of chlorophyl grains adherent to the interior surface. Cells of the margin of 

 the cup for two or three rows twice the breadth but not more than half the 

 depth of the others. Stomata remarkably few ; not more than from two to 

 four observed in a frond. Interior of the frond occupied with large spheroidal 

 cells, three lines the diameter of those of the epidermis. Air occupies many 

 of the interior cellular interspaces. Towards the point of attachment of the 

 new frond, the cells of the parent diminish in size and these contain some 

 brownish coloring matter. 



The tlowers and fruit of W. Columbiana, as observed in Gray's Manual, 

 have not been seen in the United States, but the fruiting plant, it is also stated, 

 has been recently discovered by Karston, in Venezuela. No flowers or fruit 

 were detected iu the Philadelphia plant. 



Dr. J. H. McQuillen performed some experiments on animals 

 with nitrous oxide before the Department, prior to which 



He remarked that every one present is no doubt aware that the recent in- 

 troduction of nitrous oxide as an anaesthetic in England, has been much 

 opposed by a number of prominent medical men there, particularly Drs. B. W. 

 Richardson and A. E. Sansom, both of whom have devoted years to the care- 

 ful study of anesthetics, and, on account of their observations, experiments 

 and contributions to the literature of aua;sthetics, have come to be regarded 

 " as of authority " in such matters ; and their combined opposition appears to 

 have had considerable eflect upon the medical profession, judging from the 

 comments in the medical journals, and the reports of proceedings of medical 

 societies opposing its use ; but the dental profession of England, aware of the 

 remarkable exemptiom from fatality which has attended the use of nitrous 

 oxide in America — frequently in tiie hands of most ignorant persons — have 

 determined to give the agent a fair trial. The result is not an uncertain one, and 

 Ijefore another year passes by nitrous oxide, in the hands of the progressive 

 members of the dental profession in Great Britain, will almost entirelj' super- 

 cede, as in this country, the use of ether and chloroform in the extraction of 

 teeth, and there is no reason why it should not be employed in the minor and 

 capital operations of general surgery. 



Dr. Richardson, in addition to his opposition to the use of nitrous oxide as 

 an agent that " had caused death in the human subject " (making this asser- 

 tion notwithstanding the fact that, in 100,000 cases or more in which it has 

 been employed in America, no fatal case can justly be attributed to it as the 

 direct cause), said at a meeting of the Medical Society of London, that '' on 

 animals it was so fatal that, with the utmost delicacy in its use, it was a critical 

 task thoroughl)/ to narcotize an animal with the gas without actually destroying life. 

 In some cases, also, animals died after recovering from the insensibility." 



In accounting for this fatalitj' in man and animals, nitrous oxide has been 

 denied the possession of aniesthetic properties, and the results obtained attri- 

 buted to asphyxia, due to " suspension of oxygenation," as in cases of death 

 from the inhalation of the fumes of charcoal or carbonic acid gas, rather than 

 impressions made upon the brain directly by the agent. It is somewhat singu- 

 lar to have such an explanation offered in connection with a substance which 

 sujiplies an excess of oxygen to the blood. It is not my intention, however, 

 this evening, to enter into the consideration of how nitrous oxide acts npon 



