The Ultra-Violet Absorption Spectra of Blood Sera. 333 



distortion of the curve, for such would imply great modification of the 

 proteins or other constituents of the serum and point to very serious changes 

 in the condition of the patient. Although about 120 specimens of patho- 

 logical sera have been studied, it would be premature at this stage to do 

 more than make a few general remarks. 



The first observation is a general one and very significant, namely that it 

 is the section e which is most usually disturbed. It is, moreover, the part 

 which shows most variation in normal or so-called normal serum, and it is 

 also here that the most marked differences between human serum and horse 

 serum, and between either of these and egg albumin, are to be found. It 

 appears, therefore, that modification of this part of the absorption band 

 corresponds with some sensitive constituent which varies either in proportion 

 or in constitution in consequence of comparatively slight changes in the 

 condition of the subject. 



Some thirty specimens of blood have been examined in connection with 

 typhoid, and the results are very encouraging. The chief effect observed is 

 that the point of least absorption value between the sections e and £ is 

 shifted from 2540 to 2510, and at the same time raised slightly. 



This result has been arrived at in two ways : First, a series of three 

 specimens of blood was taken from each of six soldiers ; (a) normal, imme- 

 diately before inoculation against typhoid ; (b) 41 hours after the 6rst 

 inoculation ; (c) 20 hours after the second inoculation, 11 days later. The 

 serum was separated and examined in the usual way, and the above-named 

 effect was observed in five out of six cases. Blood from 11 cases of actual 

 or suspected typhoid was examined. In six instances the above effect 

 obtained fully ; in two, the displacement was to 2530 only ; in two, the 

 position was unchanged. In one, described as clinically* a typical case of 

 typhoid and as having failed three times to give the Widal reaction, the 

 movement was in the opposite direction, to 2550. 



In most cases there is a reduction in the amplitude of the curve between 

 the depression at 2540 and the head at 2800. 



Another modification observable in the inoculation cases is that the step- 

 like prominence at the bottom of section j is somewhat greater after 

 inoculation than before in five cases out of six. The sixth case is also 

 the exception with regard to the displacement modification mentioned 

 above. 



Scarlet fever has proved very interesting. It exhibits a more or less 

 strong disturbance in the protein band in about half of the 33 cases which 

 have been examined. The change is not constant either in quality or 

 quantity, but it is always in the central protein band ; usually section e is 



