178 KANSAS UNIVERSITY SCIENCE BULLETIN. 



5 mm. up to full term, and in any desired quantity. For this 

 purpose it is sometimes recommended that a room be secured 

 in or near the packing-house, where the pregnant uteri can 

 be taken for examination. Unless, however, very small em- 

 bryos are desired, this will not be found necessary. It is 

 better to obtain a table in the cleaning room as close as pos- 

 sible to where the uteri are removed. This permits the hand- 

 ling of the material with much greater dispatch, with sufficient 

 convenience for all practical purposes, and with little, if any, 

 greater amount of incidental unpleasantness. 



For equipment, the collector needs only a good supply of 

 containers, a small graduate, fixatives, and, unless he is de- 

 sirous of some special kind of material, one pair of small 

 scissors ; anything more is only in the way. For fixation, 

 Kleinenberg's picro-sulfuric mixture has been found quite 

 satisfactory for embryos up to 10 or 15 mm. long and Zenker's 

 fluid for all sizes. The larger ones, however, must have the 

 body cavity punctured to secure sufficient penetration of the 

 fixative. Where the size of the embryo does not preclude its 

 use, the former is the more satisfactory, both on account of 

 the simplicity of the after-treatment required, and on account 

 of the greater length of time material can be left in it. Later 

 stages, for the purpose of dissection, are best preserved in 

 Erlichi's mixture : 



Potassium dichromate 2^ gr. 



Cupric sulfate 1 gr. 



Water 100 cc. 



Containers of standard size should be used and the dry ma- 

 terials of the fixatives should be weighed out and carried in 

 vials with sufficient amounts in each to make one container 

 of fluid. It is more practicable, however, to carry the liquid 

 ingredients in bulk and measure them out as needed. The 

 mixing of the fixatives is thus very simple, since the only 

 other ingredient, water, is always, in a cleaning room, near 

 at hand. In case Zenker's fluid is used, enough Muller's 

 should be taken to give each embryo a preliminary bath to 

 fix the albuminates, which would otherwise impede the action 

 of the former fluid. 



The pregnant uteri can be distinguished by their greater 



