December 9, 1921] 



SCIENCE 



581 



sorbent cotton, the double purpose is served 

 of stimulation of the vessels, causing them 

 to dilate, and of plastering down the hair upon 

 the skin, making the veins and arteries more 

 visible. When the needle is withdrawn the 

 alcohol must be well wiped off before the 

 wound will close. Sometimes when an attempt 

 to enter the median artery is for any reason 

 unsuccessful, the blood will be seen to leave 

 the vessel entirely and remain so for a con- 

 siderable time, due to contraction of the ar- 

 terial wall which was probably pricked by the 

 needle. Vigorous rubbing, however, will bring 

 the normal circulation back. 



Shaving or sterilizing the ear is unneces- 

 sary when it is not desired to preserve the 

 blood for more than immediate use. Several 

 hundred injections and bleedings during the 

 past year or two have shown no ill effects 

 whatever. Eabbits apparently rival avian 

 forms in their resistance to infection. Nu- 

 merous subcutaneous and intraperitoneal in- 

 jections without shaving or sterilizing the body 

 surface have not shown a single infection. 



A very useful sort of cage, designed by Mr. 

 George H. Bisnop for use in this laboratory, 

 makes it simple for one to perform injections 

 and bleedings alone. A box about eleven 

 inches long, four and a half wide, and six and 

 a half deep (inside measurements), has a 

 stock at the front end, the upper half of which 

 operates in a slot, and which may be fastened 

 so as to allow an opening of any desired size, 

 through which the animal's head and neck pro- 

 trude. A hinged top prevents kicking up be- 

 hind. Eabbits take very quietly to this tem- 

 porary confinement once they are placed in- 

 side the box, and are not then able to jump 

 and misdirect the needle so easily as when one 

 is attempting to hold the animal. This cage 

 is here illustrated. 



George F. Forster 

 ZooLOGicAii Laboratory, 

 TJNrvERSiTT OP Wisconsin 



adsorption by soil colloids 

 (preliminary paper) 

 For some time we have been working on 

 the adsorption of soil colloids. We believed 



that this problem could best be solved by 

 preparing these soil colloids separately in the 

 purest possible condition, and then trying 

 each colloid with the nine following respec- 

 tive salts: potassium nitrate, potassium sulph- 

 ate, potassium acid phosphate, calcium nitrate, 

 calcium sulphate, calcium acid phosphate, 

 magnesium nitrate, magnesium sulphate, 

 magnesium acid phosphate. 



The individual salts have been tried on 

 silica, aluminium, and iron gels, and the 

 humus is now in the process of preparation. 

 We have worked on the adsorption of each 

 ion separately. A few results are given to 

 show the trend of the work. 



Cone. 



N/10 

 N/20 . 

 N/40 . 

 N/400 



ADSORPTION BY IRON GEL 



^ Mg. of Mg. Adsorbed Mg. of SOi Adsorbed 



■'°°<=- per Gram of Gel per Gram of Gel 



N 9.7 31.9 



N/5 8.0 30.7 



N/10 5.7 28.3 



N/20 4.3 23.2 



ADSORPTION OF ALUMINIUM GEL 



There was less than the equivalent amount 

 of calcium adsorbed at the various ooncentra- 

 tior«. 



ADSORPTION OP SILICA GEL AT VARIOUS Ph VALUES 



P Value ^^' °^ ^ Adsorbed 



ii per Gram of Gel 



3.888 — 0.68 



6.089 1.74 



7.692 6.56 



9.501 9.62 



We have also varied hydrogen ion concen- 

 tration and followed the adsorption curves 

 for the respective ions with the idea of show- 



