210 R. G. WESTALL 
filtrate. DENT ef al.°® found that the rate of clearance of cystine in cystinuric patients 
was about the same as the rate of glomerular filtration. The renal clearances of lysine, 
arginine and ornithine are also raised®®, ©. It seems therefore that in this disease 
there is an error in the transport of these four amino acids through the lumen of the 
renal tubule. That these emino acids should be involved; and no others, may be 
because they have a certain similarity of chemical structure, for instance a similar 
spacing between the two amino groups. This was suggested by DENT AND RosE*®, 

Fig. 11. A paper chromatogram of the urine of a patient with phenylketonuria. 
Further evidence that these amino acids do, in fact, share the same transport mecha- 
nism has been obtained by RoBsoN AND RosE® and SMEENK®. They found that a 
considerably increased excretion of cystine and, indeed, of the other two amino 
acids, could be induced artificially in normal individuals by the infusion, by vein, of 
lysine and of arginine. 
Galactosaemia. It has been found that certain babies cannot tolerate milk. Infants 
with this defect, which has been found to be hereditary, appear normal at birth but 
References p. 217/219 
