ARTIFICIAL METHODS OF FEEDING 815 



more satisfactory and useful and the future will have to determine the 

 possibilities of subcutaneous feeding, although a certain amount can be 

 done in this way now. Any substance used must be capable of direct 

 assimilation, non-irritating and easy of sterilization. 



Protein. Protein has been used in many different forms, as egg 

 albumin, peptone, alkali albuminate and propeptones, but it was found that 

 all these forms of protein lead to severe local reactions abscess formation 

 and breaking down of the tissues. Experimen tally (k). it was found pos- 

 sible in dogs by small and repeated injections of skimmed milk peptonized 

 one and a half hours, to supply a certain amount of protein, the nitrogen- 

 ous balance showing a loss of only 0.8 to 0.5 gm. per day. These injections 

 were toxic and particularly so unless the dose was begun low and very 

 gradually increased, so that this form of protein is not practical and 

 should not be used. Ascitic fluid and blood serum, have also been used 

 with better result and a certain amount of protein can be supplied and 

 made use of without toxic symptoms, although large doses were found to 

 cause renal irritation. Blood serum contains practically 1 per cent 

 protein, and ascitic fluid 0.17 to 1 per cent, hence in order to supply 

 sufficient protein it would be necessary to give even on the basis of 

 Chittenden's low estimate of 0.12 gm. nitrogen per kilo daily, 840 to 

 4,200 c.c. of fluid for a man weighing 70 kg., depending on whether blood 

 serum or ascitic fluid was used, certainly too large an amount to' be readily 

 obtained or used on account of mechanical objections. At the same time, 

 it is possible to use from 300 to 400 c.c. daily probably without detriment 

 to the organism, although the urine should be watched for signs of renal 

 irritation. In dogs, even large amounts were used and apparently utilized, 

 although there was always a negative nitrogen balance in two- or three-day 

 periods of from 0.04 to 4.35 gm. nitrogen; in starvation the balance being 

 for two days, 3.83 gm. nitrogen daily (Z). 



When serum or ascitic fluid is aseptically drawn, it can be used safely ; 

 if there is any question it should be heated to 55 C., which makes it 

 opalescent, but does not coagulate it. 



Horse serum heated to 65 C. in amounts of 100 to 120 c.c. was used 

 by Salter(r?0> who noted that the urinary nitrogen was increased. This, 

 however, is not an homologous serum and could not be used for nutritional 

 purposes without first testing the patient for serum reaction, and is not 

 suitable for hypodermic feeding. 



Fats. Fat injections have been tried in various forms but too few 

 accurate metabolic estimations have been carried out to place the matter 

 on a firm footing. Von Leube used subcutaneous oil injections 20 to 30 

 gm. at a time two or three times daily, and concluded that the oil was 

 absorbed and metabolized as evidenced by lowered excretion of nitrogen 

 in the urine. Absorption is very slow, and care must be taken not to 

 inject the oil into a vein which of course would result in fat embolism. 



