In particular, when PHA is inserted beneath the thin skin of a bird's wing, it causes a swelling a bit like a mosquito bite.
2
通过用压感卡尺测量肿包大小能够使Spottiswoode博士得以确定免疫反映的强度。
Measuring the swelling with pressure-sensitive callipers allowed Dr Spottiswoode to determine the strength of each bird's immune system.
3
但这也是要付出代价的:肿包越大,免疫反映对个体的压力就越大而且为了对抗病菌还会消耗更多的能量。
That response, however, comes at a price. The larger the swelling, the greater the immune stress on the bird and the more energy its immune system is consuming to fight off the effects of pathogens.