LAST LECTURE OF LOUIS AGASSIZ. 223 



very incomplete, while with reference to our domesticated 

 animals we are even more in the dark. Not that objection 

 is made to dissecting a dead animal, one which has died upon 

 the form, — the scruples do not go so for as that, — but there 

 is an objection to the examination of the living animal, first, 

 on the ground of the possible suffering, and secondly, on 

 another ground, touching everybody even more nearly per- 

 haps, namely, — the cost of the experiments. We may ex- 

 amine the embryos of rabbits repeatedly without draining our 

 pockets, but if we would study the early condition of the 

 germ in our more valuable animals, we meet at once with this 

 almost insuperable difficulty, that we must kill a large number 

 in order to have specimens enough to carry on such researches . 



The natural consequence is, that to this day, I do not know 

 one physiologist who has traced the growth of any of our 

 more valuable domesticated animals. The highest and the 

 most costly of which we know anything, is the dog. Even 

 the sheep has not been investigated, nor 'the goat, nor the 

 pig. Of the cow and the horse we know almost nothing, ex- 

 cept by inference, although we understand in a measure their 

 organs, and the functions performed by them, some dis- 

 sections having been made to elucidace that part of the sub- 

 ject. 



It must be understood, therefore, that whatever I say of 

 the growth of these animals is inferential, — based upon the 

 development of other animals more within the reach of in- 

 vestigation, to the embryology of which our knowledge of 

 comparative structure enables us to give a wider application. 

 I am the more anxious that you should appreciate this diffi- 

 culty, because we shall never fill the blanks in our informa- 

 tion till the opportunities so much needed are given to future 

 students. It is not even enough to know the difficult}^, and 

 be ready to meet the expense of further investigation ; you 

 must also prepare the observer. You would hardly believe 

 me when I say, that there are very few naturalists in the 

 United States competent to make such an investigation ; and 

 yet this is literally true. I will add that of those able to do 

 the work, not one is placed in a position under which he could 

 undertake it. Those who are capable of such researches are 

 so overworked, so overloaded with duties, so cramped for a 



