Greenhalgh, Martin, Coghlan, Hitter, Stohlmann, Coghill, Behrer, White and others, then constructed two-bladed instruments, of which number the Greenhalgh-Gusserow is generally used. This instrument consists of two Simpson's metrotomes. It carries two slender blades which are sunk in a groove, from which they emerge as the instrument is with drawn. In Martin's instrument the entire mechanism is exposed to view, and it is slightly curved on the flat. Stohlmann's metrotome is simpler, and Kehrer modelled his instrument after it. It consists, as does Cog hill's, of a long, slender pair of scissors cutting outwards, and controlled by a screw in the handle.
For these complicated instruments Sims substituted the scissors and the knife. He incised the lateral walls of the cervix with the scissors up to the vaginal insertion, and extended the incision by the knife above the internal os. Kfichenmeister's modification differs purely in the fact that the incisions are made from without inwards.
If we except discission by means of Simpson's hysterotomes, there are numerous objections to the other instruments, the chief of which is the fact that they are all very difficult to keep clean, in particular Green halgles. Discission by means of the knife and the scissors requires more skill, assistants, and time. The operation, however, is almost painless; the operator has full control of the procedure, and may make his incision as deep as he pleases, and in any direction he wishes. Only in case of the highest degrees of narrowing of the cervix may it be impossible to pass the knife by the internal os, and thou one of the slender knives of Peaslee, White, or Galabin may be used. • Aside from resort to discission to enable us in exceptional instances to insert a tent, and aside from it as a substitute for tents, stenosis or similar changes in the cervix at the external or the internal os are the most frequent indications for the operation. The most common site of narrowing is the external os. The changes at the internal are usually due to flexion or congestive phenomena in the mucous membrane, swell ing cicatrices, etc Narrowing of high degree, such as where a sound .07 of an inch thick will not pass, is very' exceptional. As to the slighter degrees of narrowing opinions vary greatly. Martin insists that the ex tremity of the ordinary uterine sound should pass; Peaslee gives us a pre cise scale of narrowing, and considers incision of the internal os indicated .
when a sound one-eighth in diameter will not pass, and of the external os at one-sixth inch and below. In about 400" discissions, I have been guided rather by the presence of catarrh, frequently in conjunction with sterility and dysmenorrhea. We often indeed see, in case of very narrow
os, no symptoms of stenosis, sterility, dysmenorrhea, or retention of se cretion, while, on the contrary, the latter is the case where the os is very large. It is apparent then that the indication for discission may be present even in case of large external os, because of the existence of a uterine or a cervical catarrh.
Stenosis itself far less frequently attracts attention than the functional disturbances caused by it, as, for instance, dysmenorrhea and sterility. Although it is irrational, in the presence of a subjective symptom and in the absence of anatomical cause, to seek for the indication of an opera tion, and even though it cannot be held as true that dysmenorrhceic women are very frequently sterile, still to-day it is not contrary to sound practice to perform discission in case of sterility and of dysmenorrhea even though no marked stenosis be present. The evidence that women who have borne children more readily conceive than those who have not leads us to the belief that it is right to resort to discission in case of sterility, even though an examination shows no abnormality in the geni tal system. Seeing that the operation at the external os is almost en tirely without risk, the indication is a just one, but as regards the internal os, the most frequent site of stenosis, it is not. Sufficient statistical data in regard to this 'point have not been given us. The 483 discissions practised by Haartmann, G. Braun, Martin, liehrer, and myself, up to 1878 were followed by good results in 148 (30.7 per cent.). These ob servations, however, are not precise enough in regard to whether the discission was performed for sterility alone, or partially on account of some abnormality. Tile opponents of discission oppose to it the ex tremely small size and the power of motion of the sperm cells, and further, the many recorded cases of conception in cases of exquisitely marked stenosis, flexion, unruptured hymen, and the like. Although we are far from warranted in the belief that the chief cause of sterility resides in abnormality of the vaginal portion of the cervix, yet it must be granted that the chances of the spermatozoa entering the uterus are greater where the orifices of the organ are larger. It must further be noted that certain states of the orifices are unfavorable for conception. Olshausen, Martin, and I, have noticed this fact in connection with rigid os, and it seems as though the opening power of the os were of greater importance than its absolute width, and the same is apparent from the researches of Hoffmann and Basch in animals.