PROCEEDINGS OF SOCIETIES. 



59 



The thanks of the meeting were unanimously voted to Dr. Hoggan, 

 and a short discussion followed. A number of beautiful specimens, 

 both of hard and soft substances, cut by the machine, were exhibited, 

 and much interest was shown in them. 



A paper by Dr. Braithwaite, " On the Histology of Plants," being 

 the fifth of a series written for the club, was taken as read ; and it 

 was announced that the demonstration of it, by the exhibition of a 

 number of microscopical preparations of pith, bark, cuticle, &c., would 

 take place at the next conversational meeting, on the 12th of June. 



Announcements of meetings, excui'sions, &c., were made, and the 

 meeting concluded with the usual conversazione. 



Microscopical Section of the Academy of Natural Sciences 

 OF Philadelphia. 



January 5, 1874. — Director W. S. W. Euschenberger, M.D., in the 

 chair. — Mr. Holman's " siphon slide " for the microscope was exhibited 

 in operation by Dr. Joseph G. Richardson, who remarked that the 

 apparatus was composed essentially of a strip of plate glass, of the 

 ordinary length and width (namely, three inches long by one inch 

 wide), but double the usual thickness, in the upper surface of which 

 had been ground a shallow groove, elliptical in both its transverse and 



longitudinal section, and deeper toward one extremity. The excava- 

 tion was so arranged as to receive a small fish, tadpole, or triton, and 

 retain it without, on the one hand, injury from undue pressure, but 

 without, on the other, permitting any troublesome gymnastics beneath 

 the thin glass cover, which, when applied, formed the ceiling of the cell. 

 The great improvement of this slide consisted, however, in the imbed- 

 ding of a small metallic tube (communicating with each extremity of 

 the groove), in either end of the slide, and the adaptation to these two 

 tubes of pieces of slender caoutchouc pipe, about eighteen inches in 

 length, one of these being intended for the entrance and the other for 

 the exit of any fluid, cold or Jiot, which it might be desirable to employ. 



