C.C. Twort to K. Pearson, 3rd March 1932.- External URL
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Sent From (Definite): C.C. TwortSent To (Definite): Karl PearsonDate: 3 Mar 1932
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Holder (Definite): University College London: Special Collections
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Sent fromC.C. Twort
3 Mar 1932
Description:
‘Dear Professor Karl Pearson,
Very many thanks for your letter. I am afraid, however, that you have not quite understood exactly what we have been doing with reference to colour of animal and cancer. You were kind enough to suggest our carrying out experiments along certain lines but, of my memory serve me correctly, I informed you at the time that we were not in a position to undertake elaborate colour experiments meanwhile. As a matter of fact we have recently commenced some experiments keeping record of colours whether a tumour developed or whether it did not, but these are not yet completed.
The paper we propose to publish and in which I should like to acknowledge your kind interest, embodies an analysis of selected experiments performed 3 or 4 years ago, These experiments we have attempted to do by making our calculations on a percentage basis so that we could correlate experiments with agents of different carcinogenic potencies and from our results there seems to emerge some curious facts. For instance, there is an indication that colours which are sensitive to oils are relatively resistant to tars and vice versa, so that in 40 oil experiments the piebald animals were, in every instance, not only later in developing tumours than their self-coloured companions, but the 8 piebald groups occupied the last 8, out of a possible 16, positions as regards sensitiveness. When we come to consider tar the opposite state of affairs existed although in this case in only 7 out of the 8 couples was the piebald more sensitive than its self-coloured companion. In two tar groups of 30 experiments and two oil groups of 40 and 50 experiments respectively deviation from the mean was less among the self-pigmented eye animals than among the piebald-albino eye group, the sign being, of course, reversed in the tars and oils in both groups.
From our analysis we are satisfied that there is a difference in the sensitiveness of animals, either according to the strength of the agent or according to the type of compound present, our experiments favouring the former hypothesis. We imagine that the explanation of this seeming paradox will be found in the domain of infection and immunity in general. We are now scrutinising our figures to find out the colour classes which give the maximum and minimum deviation respectively, the latter being presumably the class of choice for experiments entailing the estimation of relative carcinogenic potency.
We very much appreciate the suggestions you have made to us and for the interest you have taken in the matter and we should certainly like to submit to you records of our recent experiments when they are completed if you would be interested to examine them.
Yours sincerely,
C.C. Twort.’
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Sent toKarl Pearson
3 Mar 1932
Description:
‘Dear Professor Karl Pearson,
Very many thanks for your letter. I am afraid, however, that you have not quite understood exactly what we have been doing with reference to colour of animal and cancer. You were kind enough to suggest our carrying out experiments along certain lines but, of my memory serve me correctly, I informed you at the time that we were not in a position to undertake elaborate colour experiments meanwhile. As a matter of fact we have recently commenced some experiments keeping record of colours whether a tumour developed or whether it did not, but these are not yet completed.
The paper we propose to publish and in which I should like to acknowledge your kind interest, embodies an analysis of selected experiments performed 3 or 4 years ago, These experiments we have attempted to do by making our calculations on a percentage basis so that we could correlate experiments with agents of different carcinogenic potencies and from our results there seems to emerge some curious facts. For instance, there is an indication that colours which are sensitive to oils are relatively resistant to tars and vice versa, so that in 40 oil experiments the piebald animals were, in every instance, not only later in developing tumours than their self-coloured companions, but the 8 piebald groups occupied the last 8, out of a possible 16, positions as regards sensitiveness. When we come to consider tar the opposite state of affairs existed although in this case in only 7 out of the 8 couples was the piebald more sensitive than its self-coloured companion. In two tar groups of 30 experiments and two oil groups of 40 and 50 experiments respectively deviation from the mean was less among the self-pigmented eye animals than among the piebald-albino eye group, the sign being, of course, reversed in the tars and oils in both groups.
From our analysis we are satisfied that there is a difference in the sensitiveness of animals, either according to the strength of the agent or according to the type of compound present, our experiments favouring the former hypothesis. We imagine that the explanation of this seeming paradox will be found in the domain of infection and immunity in general. We are now scrutinising our figures to find out the colour classes which give the maximum and minimum deviation respectively, the latter being presumably the class of choice for experiments entailing the estimation of relative carcinogenic potency.
We very much appreciate the suggestions you have made to us and for the interest you have taken in the matter and we should certainly like to submit to you records of our recent experiments when they are completed if you would be interested to examine them.
Yours sincerely,
C.C. Twort.’
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