131a. =Small Sliding Microtome=, length of bed 21 cm, heavy knife-carrier, object clamp for specimen 25 mm diam., micrometer screw with disc graduated into 100 degrees, each division representing a motion of 0,005 mm. Price including knifeholder No. 139, without knife =24.--= [Illustration: Small Sliding Microtome No. 131a.] =Microtome knives.= (Made by W. Walb.) =A. Thoma's Model=, plano-concave, with handle adapted for clamping immediately to the knife carrier of the microtome, in box. [Illustration] 132. Length of cutting edge 36 cm =26.50= 133. " " " " 24 cm =13.25= 134. " " " " 16 cm =8.50= 135. " " " " 12 cm =5.50= =B. Jung's Model=--plano-concave--requires knife-holder No. 139--in box. [Illustration] 136. Length of cutting edge 24 cm =11.25= 137. " " " " 17 cm =6.--= 138. " " " " 12 cm =4.75= 139. =Knife-holder= designed for Jung's Microtome knife =4.--= 140. =Freezing apparatus= for Microtomes =8.--= [Illustration: Freezing apparatus No. 140.] =Hand Microtomes.= [Illustration: No. 141.] 141. This =Hand Microtome=, shown in the figure above, screws to the edge of the table. The specimen is held in a clamp which may be removed from the instrument, and which is raised by a micrometer screw to which a large disc is attached, the edge of which is milled and graduated, each degree of the graduation representing an elevation of the specimen of 1/100 mm. The knife is manipulated by hand and in cutting slides over two narrow glass plates which serve as a track for it. The length of this track is 7 cm =12.--= 142. =Cylinder Microtome.= The specimen is held by means of a clamp-screw in a hollow cylinder. This entire cylinder is raised within another cylinder which bears the cutting table by means of a screw with milled and graduated head. Each division of the graduation represents a motion of the inner cylinder of 1/100 mm. In cutting the edge of the knife is made to pass over the surface of the glass cutting table, the diameter of which is 7 cm =6.--= [Illustration: Cylinder Microtome.] 143. =Microscopic section-cutter=--razor form--of best quality, plano-concave, for microtomes No. 141 and 142 =1.25= =Miscellaneous Accessories.= [Illustration:Analizer. Polarizer. Polarizing Apparatus No. 144.] 144. =Polarizing Apparatus= for Food Analysis.