440 PROCEEDINGS OF THE SOCIETY. 



(sagittal sections) the entire organs of the body, the nervous cord 

 could be well seen, as could also the gullet with its muscles. A 

 rough sketch was made on the slate to illustrate the chief points of 

 interest. 



Mr. Beck thought the remarks of Mr. Hartog were exceedingly- 

 interesting, for if they were ever really to understand these structures 

 it must be by means of sections. He was glad to have heard the very 

 practical remarks which had been made, and hoped they would be 

 the means of inducing others to practise tbe process, feeling sure 

 that such a study would elucidate many points which were now 

 involved in mystery. 



Mr. Stewart inquired whether in cutting the sections a microtome 

 was used, or whether they were cut by hand. It also occurred to him 

 that this process might be very useful in the preparation of sections 

 of many of the soft-bodied creatures such as the mites or the Arach- 

 nida, fur it was very difficult to make out many parts of their anatomy 

 by any process of dissection. 



Mr. Hartog, in rejily, said that in all cases where s-^ctions had to 

 be cut in series a microtome was necessarily used in order to secure 

 perfect regularity of thickness. Zeiss's microtome was the one he had 

 employed, using oil to moisten the razor. He agreed that the process 

 would be very liseful in the case of mites and spiders, but he thought 

 it well to remark that picric acid — so much in favour for some 

 purposes — should be avoided, as it penetrated too freely and caused 

 the soft tissues to shrink from the chitinous body-wall. 



Mr. Crisp called attention to two Microscopes which he had 

 brought for exhibition ; one of these, made in Dundee— which it had 

 been jiroposed to call the " Jumbo " Microscope — stood 4 feet high, 

 with a tube 4 inches in diameter, and weighed about 1^ cwt. It must 

 have been made about 50 years ago. The other (the " Midget ") 

 made by Mr. S. Holmes — shown by way of contrast — was completely 

 finished for use, its entire height being only 3 inches, and its weight 

 only a few ounces. Six of such Microscopes could be enclosed in 

 the eye-piece of the larger one. He also exhibited the " Acme " 

 Class Microscope (see p. 251), and Browning's Portable Microscope 

 (see p. 252). 



Mr. Beck examined the large instrument and made some remarks 

 as to the peculiarity of its construction. 



Dr. Loew's note as to the chemical difference between living and 

 dead protoplasm was read, and a photograph exhibited illustrating 

 his and Bokorny's statement as to the different reaction of dead and 

 living protoplasm on silver salts (see I. (1881) pp. 906-7). 



Mr. A. W. Bennett said that the photograph represented two fila- 

 ments of Spirofjyra nitida. One of these had been subjected in a 

 living condition to the silver reagent, and the reducing effect of the 

 living protoplasm had converted the cell-contents into a black opaque 

 mass. The other filament had been killed by a 1 per cent, solution 

 of citric acid before treatment with the silver solution. In this case 



