This sketch was made during a visit to the Boyd Collection. The Boyd Collection is composed of sections of human embryonic, placental and uterine tissue mounted on glass slides and is stored in The Centre for Trophoblast Research, Cambridge University.

But how I came to have access to the collection begins with a specific group of blood cells called natural killer or NK cells. Blood cells are not only found in the blood, for as major components of the immune system they also infiltrate other organs of the body. There are various subgroups of white blood cell. Apart from shape, and size, some white blood cells that perform specific functions can be further subdivided by markers on their outer cell surfaces. For example some blood cells have specialised roles such as remembering past infectious agents. The overall function of the system as a whole is to identify and support cells that should be present and to identify and set in motion the elimination of cells that should not be there.

Many types of white blood cells are found in the lining of the womb, technically called the endometrium.  At the time that an embryo implants and during early pregnancy a cell originally described as a large granular lymphocyte and now known as an endometrial natural killer or NK cell, is present in large numbers.  Current thinking is that endometrial NK cells help human embryos to successfully implant in their mothers womb but exactly how they do that is not certain and has become controversial.

This is the area in which I used to work and publish, I haven’t lost interest in the function of NK cells just because I am no longer in the lab. So every so often, thanks to the internet, I have a look at the results of the most recent research.

In 2015 I came across an impressive paper First Do No Harm that addressed many of the problems associated with NK cell analysis and assisted reproduction. I sent a card of congratulations to one of it’s authors, Ashley Moffett, who very kindly suggested that I might like to have a look at the Boyd Collection.

My visit was brilliantly arranged by Elizabeth Harrington. In October 2015 I met Graham Burton Director of the Centre for Trophoblast Research who introduced me to the work of Professor JD Boyd, in the form of a magnificent atlas of human embryo development and of course the slides. I spent a very happy day with the slides, a microscope, camera, paper and a pencil.

In these posts I hope to chart the course of this piece of work, and to use the process of writing to explore and clarify ideas.