8 
THOMPSON YATES LABORATORIES REPORT 
ADDENDUM 
An enormous literature has grown around the subject of serum diagnosis. The general tendency- 
is to confirm its utility. From my own experience I am inclined to think, contrary to the usual teaching, 
that greater accuracy is attained by diluting the serum to at least i in 30, and regarding the formation of 
quite small groups as indicating a positive result, rather than by diluting only i in 10 and requiring large 
groups, clearing of the field, and loss of motility. The latter sign especially I regard as inessential, 
provided agglutination is present. 
My opinion that severe cases might often give feeble results has been confirmed, not only for 
typhoid but also for other diseases, so that I feel inclined to regard the tentative explanation given in the 
text as correct. 
An important development of the work on agglutination has been its extension to red blood 
corpuscles, spermatozoa, &c. They can be agglutinated by the serum of different patients or animals 
(BoRDET, Landsteiner, Dungern, Shattock, &c.). There may be some future practical diagnostic value 
in these experiments. It is interesting to recall, in this connection, the physical experiment of Sir L. 
Brunton with matches or discs of cork floating in a slightly oily liquid. The addition of acid causes 
them all to separate ; making the solution alkaline causes .iggluti nation. 
March, 1900. 
BIBLIOGRAPHY 
1 AcHARD ET Bensaude. Compt. Rend., vol. 123, p. 503. 
2 Bordet. {a) Ann. de I'lnst. Past., p. 462. 1895. [b) Ibid., p. 193. 1896. 
3 Charrin et Roger. Compt. Rend., vol. 109, p. 710. 
4 Durham, {a) Proc. Roy. Soc, vol. 59, p. 224. {b) Journal of Pathology, vol. 4, p. 13. 
5 FoERSTER. Ztschr. f. Hygiene, vol. 24, p. 500 (gives several references). 
6 Gruber. [a) Mlinch. Med. Wochschr., p. 206. 1896. {b) Wiener Klin. Wochschr., 
p. 183. 1896. [c) Verb. d. Congresses f. Inn. Medic, p. 207. 1896. 
7 GRtfNBAUM. {a) Lancet, ii, pp. 806, 1559, 1745. 1896. [b) Ibid., i, p. 451. 1897. 
8 IssAEFF. Ann. de I'lnst. Pasteur, p. 260. 1893. 
9 Levy u. Bruns. Berl. Klin. Wochschr., p. 491. 1897. 
10 Metschnikoff. Ann. de I'lnst. Pasteur, p. 465. 1891. 
11 Pfeiffer, R. Ztschr. f. Hygiene, vol. 18, p. i. 
12 Salimbeni. Ann. de I'lnst. Pasteur, p. 277. 1897. 
13 Washbourn. Journ. of Pathology, vol. 3, p. 214. 
14 Widal, {a) Bull, de la Soc. Med., p. 561. 1896. {b) Ann. de I'lnst. Pasteur, p. 353. 
1897 (contains his collected papers and many references). 
15 Wright. («) Lancet, ii, p. 809. 1896. (^) Brit. Med. Journ., i, p. 256. 1897, 
