50 



Scientific Proceedings (103). 



for a period of years in order to bring about any harmful result. 

 Danger from a lack of this dietary factor need not be apprehended 

 if the diet is otherwise complete. 



The development of rickets has been attributed by Mellanby, 

 as a result of experiments on dogs, to a lack of fat-soluble vitamine, 

 and Hopkins and Chick have termed this vitamine the "anti- 

 rachitic factor." It was found, however, that infants fed on this 

 " fat-soluble vitamine minimal diet" did not develop the well- 

 established signs of rickets — beading of the ribs, enlargement of 

 the epiphyses, weakness of the muscles, etc. We cannot believe, 

 therefore, that rickets is brought about by a deficiency of this 

 principle; all the more so, as this disorder developed in infants 

 receiving large quantities of milk containing ample fat-soluble 

 vitamine. It may be added that neither cream nor the leafy 

 vegetables, both of which are rich in this principle, were found to 

 be comparable to cod liver oil as growth stimulants. 



29 (1489) 



A method for the determination of calcium, magnesium, potas- 

 sium, sodium, chlorides and "acid-soluble" sulfur and 

 phosphorus in one sample (25 c.c.) of blood. 



By Isidor Greenwald and Joseph Gross. 



[From the Harriman Research Laboratory, The Roosevelt Hospital, 



New York.] 



The blood is laked with eight volumes of water and the protein 

 is then precipitated by the addition of one volume of 1 :i nitric 

 acid. In a portion of the filtrate chlorides are determined gravi- 

 metrically by precipitation with silver nitrate and filtering on a 

 Gooch crucible. The excess of silver in the filtrate is removed 

 with hydrochloric acid and the resultant filtrate and the remainder 

 of the blood filtrate are combined and treated with copper nitrate 

 and perchloric acid, evaporated to dryness and then to blackness. 1 

 The residue is treated with concentrated hydrochloric acid, again 

 evaporated to dryness and then dissolved in dilute hydrochloric 



1 Redness must be avoided, or potassium will be lost. This is a modification of 

 Benedict's method (Journal of Biological Chemistry, 6, 363, 1909). 



