Januakt 21, 1921] 



SCIENCE 



75 



Dall gives a letter from E. McFarland, in ficial respiration apparatus, wliicli practically 



whicli the death, of Lockhart is mentioned. 

 EosE M. MacDonald, 



Librarian 

 U. S. Bureau of Fisheries, 

 Washington, D. C. 



I 



RESEARCHES IN HELMINTHOLOGY AND 

 PARASITOLOGY 



To THE Editor of Science : The Smith- 

 sonian Institution published in 1904, the col- 

 lected "Eesearches in Helminihology and 

 Parasitology" (1844-1891) by Joseph Leidy, 

 M.D., LL.D. The issue was gratis, and is 

 now out of print. 



The writer has been applied to by a number 

 of research laboratories in comparative pa- 

 thology for reprints — he would be glad to 

 know of any one to whom complimentary 

 copies were presented, who would be disposed 

 to donate any such, for use among those en- 

 gaged in similar lines of investigation. 



Joseph Leidy, Jr. 



1319 Locust St., Philadelphia 



SPECIAL ARTICLES 



A SIMPLE DEVICE FOR GIVING ANESTHETICS 



So often in giving anesthetics to an animal 

 through the trachea cannula the student 

 either covers the intake opening with several 

 layers of gauze, or plugs the opening with 

 absorbent cotton. To these he applies the 

 anesthetic. When these substances are moist- 

 ened, the air passages which exist between the 

 fibers in the dry condition are almost wholly 

 obliterated, and the animal is more likely to 

 become asphyxiated than anesthetized. To 

 prevent this almost imiversal failing I have 

 devised a simple trachea cannula, adapted to 

 both normal and artificial respiration and an 

 appliance for anesthetization, which slips over 

 the intake opening of the cannula. 



The cannula consists of a metal T-tube, 

 Fig. 1, C. In the long part a small tube ex- 

 tending the full length is soldered. At one 

 end, I, all of the opening into the larger por- 

 tion of this double-barreled tube is closed with 

 solder, thus leaving only the smaller tube 

 open, sm. This end is attached to the arti- 



closes it during normal respiration. The 

 other end, T, is inserted into the trachea. 

 The end views of these portions of the tube 

 are shown at the left and right of the figure. 





^ZM 



SIB 



Sm Shi 



FiQ. 1. A, anesthetic cone; B, circular base; C, 

 cannula; D and E, intalie and outlet tubes; G, 

 gauze; H, hole into intake tube; I, end for at- 

 tachment to artificial respiration apparatus; 0, 

 opening; S, wire screen; sm, small tube; T, 

 trachea end of cannula. 



The device for the administration of the 

 anesthetic is made from a small hemispherical 

 tea strainer (Fig. 1, A). The opening of the 

 strainer is soldered to a circular metal plate 

 (B) with a hole (H) in the center, and a 

 metal tube (E) soldered on the lower surface. 

 This tube is large enough to easily slip over 

 the side tube (D) of the cannula. One or 

 two layers of gauze (G) are spread over the 

 wire screens (S) of the strainer and fastened 

 by passing a string or rubber band around the 

 lower margin. The gauze, which can be read- 

 ily replaced, is thus held away from the intake 

 opening and permits of free passage of air 

 and the thorough vaporization and mixing of 

 the anesthetic with good air. In this manner 

 a few drops of the anesthetic at a time are 

 sufRcient to keep the animal in complete 



