Correspondence by Dr H.V. Mark—published in NZMJ 1910 May;8(34):44-5. To the Editor N.Z. Medical Journal. Sir,—About four years ago I wrote a letter on the subject of Cancer, containing a suggestion as to \"possible\" treatment, but, upon re-consideration, the notion seemed so crude and based on such slight evidence (and that entirely hypothetical) that I decided not to send it. I have followed as closely as I have been able the published results of those engaged in cancer research, and lately I concluded from some observations made by Drs. Bashford and Murray that the deductions I made a long time ago might have some justification. I am therefore sending this letter for what it is worth. It has been recorded by several observers how slight a modification of the economy of the animal experimented upon is sufficient to prevent the successful inoculation of cancer; that mouse cancer will not grow continuously in other animals, that a cancer graft from a tame mouse will not affect a wild one, an English graft will not affect a German one, etc, Drs. Bashford and Murray made the curious observation that a few drops of blood from a healthy mouse injected into another healthy mouse would make the inoculation of cancer grafts in mouse No. 2 impossible. Mr. Edmond Owen, in his Bradshaw lecture, says, \"If these results are confirmed by other observers, the next question will be, Why?\" These results have since been confirmed (September 25th, 1907). It was due to reading this indication of the very slight modification in the mouse's blood, affecting the susceptibility of the second mouse to cancer, that caused me to write this letter, conveying my previous impressions of the subject. On thinking the matter over, I could not call to mind any animal that with age does not become liable to cancer, but was impressed by the well-known fact that young animals, are practically exempt, and are insusceptible to inoculation, the inference being that the young are ill some subtle way \"protected.\" If this be so, then I think that it is to the young we must look for protection, which, by the way, seems only natural. The same species living under the same conditions are alone influenced. I therefore venture, with all humility, to suggest that the young of the same species susceptible to inoculation with cancer after a certain age may possibly be looked to, being themselves insusceptible, to provide the material for the protection of the older and incurable individuals. My proposal amounts to this:- That human blood from a young subject, if transfused, might (reasoning from analogy) be supposed to contain some substance, incompatible with cancer life, and likely to afford protection from the disease and possibly exert some curative influence, I have not heard of its having been tried or even suggested, and few fond parents would be willing to supply the\" needful\" in the interests of those not related to them, made especially as an experiment, even if based on a reasonable hope of success. But, obviously, no certain result is possible if no attempt be made, and perhaps frequently repeated. I certainly think an attempt on the lines indicated rational and justifiable, even if followed by failure; but—should it succeed! And it certainly has the merit of never having been tried. I cannot even suggest whether the young blood from a cancerous stock would be likely to exert more influence than blood free from such hereditary\" taint, if such exist. —I am, Sir, etc., etc., H. V. DREW, :F.R.C.S., Eng. Timaru, 10th January, 1910.

Correspondence by Dr H.V. Mark—published in NZMJ 1910 May;8(34):44-5. To the Editor N.Z. Medical Journal. Sir,—About four years ago I wrote a letter on the subject of Cancer, containing a suggestion as to \"possible\" treatment, but, upon re-consideration, the notion seemed so crude and based on such slight evidence (and that entirely hypothetical) that I decided not to send it. I have followed as closely as I have been able the published results of those engaged in cancer research, and lately I concluded from some observations made by Drs. Bashford and Murray that the deductions I made a long time ago might have some justification. I am therefore sending this letter for what it is worth. It has been recorded by several observers how slight a modification of the economy of the animal experimented upon is sufficient to prevent the successful inoculation of cancer; that mouse cancer will not grow continuously in other animals, that a cancer graft from a tame mouse will not affect a wild one, an English graft will not affect a German one, etc, Drs. Bashford and Murray made the curious observation that a few drops of blood from a healthy mouse injected into another healthy mouse would make the inoculation of cancer grafts in mouse No. 2 impossible. Mr. Edmond Owen, in his Bradshaw lecture, says, \"If these results are confirmed by other observers, the next question will be, Why?\" These results have since been confirmed (September 25th, 1907). It was due to reading this indication of the very slight modification in the mouse's blood, affecting the susceptibility of the second mouse to cancer, that caused me to write this letter, conveying my previous impressions of the subject. On thinking the matter over, I could not call to mind any animal that with age does not become liable to cancer, but was impressed by the well-known fact that young animals, are practically exempt, and are insusceptible to inoculation, the inference being that the young are ill some subtle way \"protected.\" If this be so, then I think that it is to the young we must look for protection, which, by the way, seems only natural. The same species living under the same conditions are alone influenced. I therefore venture, with all humility, to suggest that the young of the same species susceptible to inoculation with cancer after a certain age may possibly be looked to, being themselves insusceptible, to provide the material for the protection of the older and incurable individuals. My proposal amounts to this:- That human blood from a young subject, if transfused, might (reasoning from analogy) be supposed to contain some substance, incompatible with cancer life, and likely to afford protection from the disease and possibly exert some curative influence, I have not heard of its having been tried or even suggested, and few fond parents would be willing to supply the\" needful\" in the interests of those not related to them, made especially as an experiment, even if based on a reasonable hope of success. But, obviously, no certain result is possible if no attempt be made, and perhaps frequently repeated. I certainly think an attempt on the lines indicated rational and justifiable, even if followed by failure; but—should it succeed! And it certainly has the merit of never having been tried. I cannot even suggest whether the young blood from a cancerous stock would be likely to exert more influence than blood free from such hereditary\" taint, if such exist. —I am, Sir, etc., etc., H. V. DREW, :F.R.C.S., Eng. Timaru, 10th January, 1910.