1. The method described by Elford for the preparation of graded collodion membranes suitable for ultrafiltration was found to give excellent results, and his findings are fully confirmed. 2. A formula is given for the preparation of collodion from which satisfactory membranes of graded porosity can be prepared. 3. The technique and apparatus used in the preparation, and standardization of membr...

abstract objective development is a complex process, completed over a specific period of time, through the maturation of the nervous system. it is affected by genetic, ethnic, nutritional, social, and economic factors; one of the environmental factors affecting the acquisition of motor skills in infants is the use of baby walkers. since this device is very commonly used for infants in our count...

1. It is shown that collodion membranes which have received one treatment with a 1 per cent gelatin solution show for a long time (if not permanently) afterwards a different osmotic behavior from collodion membranes not treated with gelatin. This difference shows itself only towards solutions of those electrolytes which have a tendency to induce a negative electrification of the water particles...