400 



SERIAL MICROSCOPIC SECTIONS 



[Ch. XI 



Or with such an organ as the hver, the skin, etc., the sections may- 

 be parallel with the surface {Surface Sections) or at right angles to 

 the surface {Vertical Sections). 



§ 650. Order of serial sections. — Some plan must be adopted in 

 arranging the series or only confusion will result. An excellent plan 

 is to arrange the short pieces of ribbons for a given shde as the words 

 on a page are arranged. That is, section No. i is at the upper left- 

 hand corner. The next row of sections begins where the first row 

 left off, etc. (fig. 237). 



As the paraffin stretches considerably one must cut the ribbons 

 into pieces considerably shorter than the cover-glass to be used. 



Pig 

 23 



Fig. 237. A Slide op Serial Sections Showing the Arrangement and Ordee 

 OP THE Sections; Also the Labeling as the Slide. 



Both the paraffin and collodion methods are adapted to the prepa- 

 ration of series. The paraffin ribbons are easier to manage and 

 easier to make than the serial sections in collodion. 



By arranging the collodion sections as they are cut on the knife 

 in collodion sectioning (§ 632), one can put them on the shde in per- 

 fect series by the tissue paper method (§ 633). 



If the sections are large, as in cutting serial sections of the central 

 nervous system, the series can be kept in order in a small dish by put- 

 ting a piece of tissue paper over each section and piUng them up. If 

 the vessel is small enough the papers and sections will not shift and 

 get out of order. Or one might put a single section in a Syracuse 

 watch glass or a Petri dish. Then in mounting the sections can be 

 taken in order. 



§ 651. Numbering the serial slides. — For temporary numbering 

 a fine pen with Higgins' or Weber's waterproof carbon ink serves 



