of the volumes infused per kilogram of animal gives the true assay value of the preparation. The lethal dose of the digitalis powder, in milligrammes per kilogram of cat, is obtained by multiplying this number by 5. The number of lethal cat-doses contained in i gramme of digitalis powder is obtained by dividing 200 by the assay value.
"For the assay of digitalis tinctures, these are diluted 20 times with physiological salt solution.*> \ ._.-. --" "
"Other digitalis preparations^strcphanthus tinctures,f preparations of scilla/can be assayed on the cat by (a, corresponding method:;. (An exact description of the method, and details of the method of calculation, will shortly be published by Dr. C. de Lind van Wyngaarden).<^,_^ ^ .\L*JL e^U~v~>< ^^ ^ - ^ £<"- * "*",
"4. That no definite conclusions can be based on the clinical reports presented to the Conference, concerning the activity of the three digitalis powders which were distributed for comparison. It is necessary that these important observations should be continued on a very large number of cases, by different methods.
"5. That the methods of biological assay presented to the Conference, other than those above recommended for acceptance, should be the subject of further co-ordinated investigations."
Professor Kolle introduced the subject of the biological standardisation of salvarsan and its derivatives, with reference to the memorandum which he had presented to the Conference. The President anticipated that the Conference would be ready to accept the principle of the standardisation of salvarsan and its derivatives in relation to permanent standard preparations. It would be necessary to decide, among other points, what Institute, or Institutes, should be asked to prepare and preserve these standards. He proposed that this question, like the digitalis question, should be referred for detailed discussion to a sub-committee. This recommendation was accepted by the Conference, and the following Sub-Committee was appointed :
Professor Reid HUNT (Chairman],Professor DIXON,
KOLLE,,, HEYMANS Senr.
This Sub-Committee held two meetings, and at a later stage presented the following resolutions, which were unanimously adopted by the whole Conference :
'"The Conference recommends :
"i. That the internationally recognised biological standardisation of remedies of the arsenobenzene group should be made with a series of standard preparations, one for each of the compounds in question.
"«. That the following are the remedies which at present should be the subject of internationally recognised standardisation :
"(i) Dioxydiamino-arsenobenzene dihydrochloride (syn. salvarsan, arsphena-mine, arsenobenzol, etc.) ; and
"(2) its metallic derivatives (silver salvarsan) ; and "(3) Its sodium salt (sodium salvarsan) ;
"(4) Diozydiamino-arsenobenzene sulphoxylate of sodium (syn. neosalvarsan, neoarsphenamine, novarsenobenzol, etc.) ;
"(5) Neosilver salvarsan ;
"(6) Sulpharsphenamine (syn. sulfarsenol) ;
"m. That Professor Kolle of the Georg-Speyer Haus, Francfort on M., be requested to accept the responsibility for preparing, maintaining and distributing the standard preparations (i) to (5) on behalf of the Health Organisation of the League of Nations, and that Professor Voegtlin, of the Hygienic Laboratory, Washington, be invited similarly to be responsible for the standard preparation of (6).
"n>. That every batch of the remedies in question, before issue for therapeutic use in human patients, should be tested on normal animals for toxicity and on animals infected with a suitable strain of pathogenic trypanosomes (T. brucei, T. equiperdum, etc.) for the therapeutic potency.
'V That samples from every batch should be tested for toxicity on at least 10 mice or 5 rats, or on both, material from several separate ampules of each batch being separately tested, and that only such preparations should be passed for issue as exhibit, under identical conditions of experiment, a toxicity not greater than that of the corresponding standard sample.
"vi. That samples of each batch should be tested for therapeutic potency on mice or rats infected with a suitable strain of pathogenic trypanosomes (T. brucei, T. equiperdum, etc.) in accordance with the following principles :